JP2014081409A - Method for producing electronic device, method for producing display device, method for producing photomask, and photomask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for producing an electronic device, with which a mutual alignment error between different layers is reduced.SOLUTION: A method for producing an electronic device has: a first thin film pattern forming step to apply a first photolithography step to a substrate by using a first photomask; and a second thin film pattern forming step to apply a second photolithography step to the substrate by using a second photomask. In the method for producing the electronic device, the first photomask and the second photomask have a first transfer pattern including a translucent part, a light-shielding part, and a semi-translucent part, and the second photomask is a photomask identical to the first photomask, or the second photomask has a second transfer pattern which is formed by applying additional working to the first transfer pattern possessed by the first photomask.

Description

  The present invention relates to an electronic device manufacturing method using photolithography, and more particularly to a display device manufacturing method. Moreover, it is related with the photomask used for this, and its manufacturing method.

  Patent Document 1 describes a method for forming a pattern with high alignment accuracy in a manufacturing process of an electro-optical device or a semiconductor device. Patent Document 1 describes that the amount of misalignment of the center of the upper layer side alignment mark with respect to the center of the lower layer side alignment mark is measured, and a predetermined operation is repeated until the amount of misalignment is within an allowable value. Yes.

  Patent Document 2 describes a manufacturing method of a gray-tone mask (also referred to as “multi-tone photomask” in the present invention) capable of manufacturing a high-quality TFT (thin film transistor).

  Patent Document 3 describes a photomask pattern evaluation method and apparatus.

JP 2003-209041 A JP 2005-37933 A Japanese Patent No. 3136218

  Patent Document 1 relates to a method for manufacturing an electro-optical device and a method for manufacturing a semiconductor device, and more particularly, to a method for forming a pattern that can improve overlay accuracy as compared with a conventional method in a method for forming a laminated pattern. It is.

  For example, in the manufacturing process of electro-optical devices such as liquid crystal display devices and semiconductor devices such as LSI, various conductive films and insulating films are stacked to form elements such as transistors, diodes, capacitors, resistors, wirings, etc. (hereinafter, “ Electronic device). At this time, in order to obtain an electronic device having electrical characteristics as designed, for example, the mutual alignment accuracy of a plurality of layers constituting the electronic device is important. For example, in the case of a thin film transistor (hereinafter abbreviated as “TFT”) used in an active matrix type liquid crystal display device, a passivation (insulating layer) of each pattern of a plurality of layers constituting a TFT is used. If the formed contact hole is not accurately aligned with the connecting portion on the lower layer side, correct operation of the liquid crystal display device cannot be guaranteed. Such a situation is exactly the same in a semiconductor device such as an LSI.

  In these laminated structures, film formation and patterning are repeated as appropriate, and a process of patterning by applying a photolithography process to each of the laminated films using a photomask having a different transfer pattern is used. There are many. At this time, alignment at the time of individual patterning can be performed by referring to an alignment mark provided on the lower layer side during patterning on the upper layer side.

  However, even if the method disclosed in Patent Document 1 is useful for measuring and evaluating alignment errors, it cannot be said that this method alone can effectively reduce the alignment errors themselves.

  According to the inventor's investigation, there are a plurality of causes of alignment errors that occur in an electronic device having a laminated structure, and these are accumulated in a manufactured electronic device.

  Patent Document 2 discloses that a TFT manufactured using a photomask is produced by a photolithographic process that is performed a plurality of times in a graytone mask manufacturing process, that is, due to an overlay error of a drawing process that is required a plurality of times. A method is described for preventing malfunctions from occurring.

  Further, in Patent Document 3, in the photomask drawing process, when a pattern is drawn on a resist film, it does not necessarily match the pattern based on the design coordinate data. It is described that the quality of a mask pattern is evaluated from the viewpoint.

  That is, the positional deviation that appears as an alignment error of the electronic device is caused by the coordinate deviation of the transfer pattern that the photomask to be used already has, in addition to the accuracy of overlaying a plurality of layers mentioned in Patent Document 1. It will have an influence.

  By the way, when forming a multilayer structure of an electronic device, a different photomask is set in an exposure apparatus for each layer, alignment marks are read, and patterns are stacked. The inventors have found that the alignment error (EA) derived from the exposure apparatus used at this time is about ± 0.6 μm.

  However, the alignment error component that the photomask used itself has (as described with respect to Patent Document 3, the deviation component from the ideal coordinates that appears during one drawing is an error that is synthesized by overlaying by multiple drawing, The inventor's investigation revealed that the alignment error component EM) derived from the mask is generated at about ± 0.5 μm, which is almost the same level as the EA.

  It should be noted that it is more appropriate to evaluate the alignment error that occurs in an electronic device having a laminated structure by evaluating the relative deviation between layers rather than the absolute coordinate value of each layer. is there. That is, if layer 1 and layer 2 have the same amount of alignment error components in the same direction with respect to virtual ideal coordinates, the overlay accuracy does not deteriorate and the performance as an electronic device is improved. There is no major adverse effect. However, when there are alignment error components in different directions, the accumulation may cause an alignment error amount that may cause a malfunction of the device.

  Therefore, in the present invention, in consideration of the above, in particular, a method for reducing the alignment error component EM has been studied and achieved. That is, the present invention is an alignment error component of a photomask used in the manufacturing process of an electronic device, and a coordinate shift component that appears during one drawing is synthesized by superposition by a plurality of drawing. An object of the present invention is to obtain an electronic device manufacturing method capable of reducing the alignment error component EM.

  In order to solve the above problems, the present invention has the following configuration. The present invention provides an electronic device manufacturing method having the following configurations 1 to 8, a photomask manufacturing method having the following configurations 9 to 11, a photomask having the following configurations 12 to 14, and a display device having the following configuration 15. Is the method.

(Configuration 1)
According to a first aspect of the present invention, in the method for manufacturing an electronic device, the first photomask is formed on the first thin film or the first resist film formed on the first thin film in the step of forming the first thin film on the substrate. A first thin film pattern forming step of patterning the first thin film by performing a first photolithography process including a first exposure using a first and a second thin film pattern formed on the substrate on which the first thin film pattern is formed; By performing a second photolithography process including a step of forming two thin films and a second exposure using a second photomask on the second thin film or the second resist film formed on the second thin film. A second thin film pattern forming step of patterning the second thin film into a shape different from the first thin film pattern, wherein the first photomask and the second photomask are translucent portions The second photomask has a first transfer pattern including a light shielding portion and a semi-translucent portion, and the second photomask is the same photomask as the first photomask, or the second photomask Is a method for manufacturing an electronic device, which has a second transfer pattern formed by performing additional processing on the first transfer pattern of the first photomask.

(Configuration 2)
In Configuration 2 of the present invention, the second photomask is the same photomask as the first photomask, and the edges of the light shielding portion and the semi-transparent portion included in the first transfer pattern are as follows: 2. The method of manufacturing an electronic device according to Configuration 1, wherein the electronic device is defined by a single drawing process.

(Configuration 3)
According to the third aspect of the present invention, in the electronic device manufacturing method according to the first or second aspect, the first thin film pattern forming step and the second thin film pattern forming step apply different conditions. is there.

(Configuration 4)
According to Structure 4 of the present invention, any one of Structures 1 to 3, wherein the first thin film or the first resist film and the second thin film or the second resist film have different photosensitivities. 2. A method for manufacturing an electronic device according to item 1.

(Configuration 5)
Structure 5 of the present invention is characterized in that the first thin film or the first resist film is made of a positive photosensitive material, and the second thin film or the second resist film is made of a negative photosensitive material. It is a manufacturing method of the electronic device given in any 1 paragraph of composition 1-4.

(Configuration 6)
Configuration 6 of the present invention is characterized in that the first thin film or the first resist film is made of a negative photosensitive material, and the second thin film or the second resist film is a positive photosensitive material. It is a manufacturing method of the electronic device given in any 1 paragraph of composition 1-4.

(Configuration 7)
According to Structure 7 of the present invention, the second transfer pattern included in the second photomask is obtained by performing the additional process on the first transfer pattern included in the first photomask. The manufacturing of the electronic device according to any one of configurations 1 to 6, wherein the second transfer pattern is formed by removing a part of the first transfer pattern. Is the method.

(Configuration 8)
Configuration 8 of the present invention is characterized in that the first transfer pattern has a mark pattern having a line width that is not resolved by an exposure apparatus used when exposure is performed using the first photomask. 7. A method for manufacturing an electronic device according to item 7.

  This invention is the manufacturing method of the photomask characterized by the following structures 9-11.

(Configuration 9)
Configuration 9 of the present invention is an electronic device having a laminated structure in which a first thin film pattern obtained by patterning a first thin film and a second thin film pattern obtained by patterning a second thin film are laminated on the same substrate. A manufacturing method of a photomask for manufacturing,
The photomask has a transfer pattern that is formed on a transparent substrate and includes a light shielding portion, a semi-translucent portion, and a translucent portion,
A step of preparing a photomask blank in which a semi-transparent film and a light-shielding film are formed in this order on a transparent substrate;
A primary resist pattern for forming the light shielding portion and a provisional pattern that defines the semi-translucent portion by performing primary drawing on the primary resist film formed on the light shielding film. Forming a step;
A primary etching step of etching the light shielding film using the primary resist pattern as a mask;
Forming a secondary resist film on the entire surface including the formed light-shielding portion and the provisional pattern;
Forming a secondary resist pattern for forming the semi-translucent portion by performing secondary drawing on the secondary resist film;
A second etching step of etching the semi-translucent film using the temporary pattern and the second resist pattern as a mask;
And a third etching step of etching and removing the provisional pattern using the second resist pattern as a mask.

(Configuration 10)
Configuration 10 of the present invention is an electronic device having a laminated structure in which a first thin film pattern obtained by patterning a first thin film and a second thin film pattern obtained by patterning a second thin film are laminated on the same substrate. A manufacturing method of a photomask for manufacturing,
The photomask includes a first transfer pattern for forming the first thin film pattern on a transparent substrate,
A step of preparing a photomask blank in which a semi-transparent film and a light-shielding film are formed in this order on the transparent substrate;
A first transfer pattern forming step of patterning the semi-transparent film and the light-shielding film by performing a photolithography process to form the first transfer pattern; Is a shape for forming the first thin film pattern in the electronic device by exposure, and has a shape including a mark pattern having a line width that is not resolved by an exposure apparatus used in the exposure. In the electronic device, in order to form the second thin film pattern, a part of the first transfer pattern defined by the mark pattern can be removed by additional processing. This is a method for manufacturing a photomask.

(Configuration 11)
According to Structure 11 of the present invention, the photomask blank is formed by stacking the semi-transparent film and the light-shielding film having different etching characteristics on the transparent substrate in this order. Or a method for producing a photomask according to 10.

(Configuration 12)
Configuration 12 of the present invention manufactures an electronic device having a laminated structure in which a first thin film pattern obtained by patterning a first thin film and a second thin film pattern obtained by patterning a second thin film are laminated on the same substrate. A first transfer pattern for forming the first thin film pattern, wherein the formed semi-transparent film and the light-shielding film are respectively patterned on a transparent substrate. The first transfer pattern has a shape for forming the first thin film pattern of the electronic device by exposure, and has a line width mark pattern that is not resolved by an exposure apparatus used for the exposure. And is defined by the mark pattern to form a second transfer pattern for forming the second thin film pattern of the electronic device. The a portion of the first transfer pattern, characterized in that as it can be removed by additional processing, a photomask.

(Configuration 13)
According to Configuration 13 of the present invention, the second transfer pattern includes a translucent part surrounded by a semi-transparent part, a translucent part surrounded by a light-shielding part, a semi-transparent part surrounded by the light-shielding part, and a semi-transparent part. 13. The photomask according to Configuration 12, comprising any one of a light shielding portion surrounded by a light portion, a light shielding portion surrounded by a light transmission portion, and a semi-light transmission portion surrounded by the light transmission portion. .

(Configuration 14)
According to the fourteenth aspect of the present invention, the mark pattern includes a semi-light-transmitting portion or a light-transmitting portion having a width of 0.3 to 1.5 μm surrounding a part of the light-shielding portion of the first transfer pattern. The photomask according to Configuration 12 or 13.

(Configuration 15)
This invention is the manufacturing method of a display apparatus using the manufacturing method of the electronic device of any one of the structures 1-8 of the structure 15 of this invention.

  According to the manufacture of the electronic device of the present invention, a photomask used for a plurality of layers has the same photomask for a plurality of layers as it is or a transfer pattern is changed by additional processing. It is possible to improve the overlay accuracy by matching the individual misregistration tendencies. For this reason, for different layers, the conditions of the photolithography process are changed or the transfer pattern of the photomask is changed (additional processing). In the latter case, new processing is performed by additional processing. Does not generate alignment error components. In any case shown as an embodiment of the present invention, the edge of the transfer pattern to be transferred for each of the plurality of layers is defined by one drawing in the photomask manufacturing process. is there.

  According to the present invention, at least an alignment error component EM possessed by a photomask used in the manufacturing process of an electronic device, that is, an alignment in which a coordinate shift component that appears during one drawing is synthesized by overlay deviation due to a plurality of drawing. An electronic device manufacturing method that can reduce errors can be obtained.

It is a schematic diagram which shows the one aspect | mode of the photomask used for the process of manufacturing the electronic device of Example 1 of this invention. (A) is a schematic plan view, (b) is a schematic cross-sectional view, and (c) shows a transmitted light amount distribution on the alternate long and short dash line shown in (a) and a resolution threshold for a resist material used in the first thin film pattern forming step. It is a schematic diagram which shows a 1st thin film pattern formation process among the processes of manufacturing the electronic device of Example 1 of this invention. It is the same photomask as the photomask shown in FIG. 1, Comprising: It is a schematic diagram of the photomask used for the 2nd thin film pattern formation process of Example 1 of this invention. (A) is a schematic plan view, (b) is a schematic cross-sectional view, and (c) shows the transmitted light amount distribution on the alternate long and short dash line shown in (a) and the resolution threshold for the resist material used in the second thin film pattern forming step. It is a schematic diagram which shows a 2nd thin film pattern formation process among the processes of manufacturing the electronic device of Example 1 of this invention. It is a schematic diagram which shows the one aspect | mode of the photomask used for the process of manufacturing the electronic device of Example 2 of this invention. (A) is a schematic plan view, (b) is a schematic cross-sectional view, and (c) shows a transmitted light amount distribution on the alternate long and short dash line shown in (a) and a resolution threshold for a resist material used in the first thin film pattern forming step. It is a schematic diagram which shows a 1st thin film pattern formation process among the processes of manufacturing the electronic device of Example 2 of this invention. FIG. 6 is a schematic diagram of a photomask that is the same as the photomask shown in FIG. 5 and that is used in the second thin film pattern forming step of Example 2 of the present invention. (A) is a schematic plan view, (b) is a schematic cross-sectional view, and (c) shows the transmitted light amount distribution on the alternate long and short dash line shown in (a) and the resolution threshold for the resist material used in the second thin film pattern forming step. It is a schematic diagram which shows a 2nd thin film pattern formation process among the processes of manufacturing the electronic device of Example 2 of this invention. It is a schematic diagram which shows the one aspect | mode of the photomask used for the process of manufacturing the electronic device of Example 3 of this invention. (A) is a schematic plan view, (b) is a schematic cross-sectional view, and (c) shows a transmitted light amount distribution on the alternate long and short dash line shown in (a) and a resolution threshold for a resist material used in the first thin film pattern forming step. It is a schematic diagram which shows a 1st thin film pattern formation process among the processes of manufacturing the electronic device of Example 3 of this invention. FIG. 10 is a schematic view of a photomask obtained by additionally processing the photomask shown in FIG. 9 and used in the second thin film pattern forming step of Example 3 of the present invention. (A) is a schematic plan view, (b) is a schematic cross-sectional view, and (c) shows the transmitted light amount distribution on the alternate long and short dash line shown in (a) and the resolution threshold for the resist material used in the second thin film pattern forming step. It is a schematic diagram which shows a 2nd thin film pattern formation process among the processes of manufacturing the electronic device of Example 3 of this invention. It is a schematic diagram which shows the process of the additional process demonstrated as Example 4 for obtaining the photomask shown in FIG. It is a schematic diagram which shows the process of the additional process demonstrated as Example 5 for obtaining the photomask shown in FIG. It is a schematic diagram which shows the mask A photomask used for a 1st thin film pattern formation process among the processes which manufacture the electronic device of the comparative example 1 which is a prior art example. (A) is a schematic plan view, (b) is a schematic cross-sectional view, and (c) shows a transmitted light amount distribution on the alternate long and short dash line shown in (a) and a resolution threshold for a resist material used in the first thin film pattern forming step. It is a schematic diagram which shows a 1st thin film pattern formation process among the processes which manufacture the electronic device of the comparative example 1 which is a prior art example. It is a schematic diagram which shows the mask B of Mask B used for a 2nd thin film pattern formation process among the processes of manufacturing the electronic device of the comparative example 1 which is a prior art example. (A) is a schematic plan view, (b) is a schematic cross-sectional view, and (c) shows a transmitted light amount distribution on the alternate long and short dash line shown in (a) and a resolution threshold for a resist material used in the first thin film pattern forming step. It is a schematic diagram which shows a 2nd thin film pattern formation process among the processes which manufacture the electronic device of the comparative example 1 which is a prior art example. It is a schematic diagram which shows one Embodiment of the manufacturing method of the photomask for reducing the alignment error component EM which arises in a photomask manufacturing process. FIG. 20 is a schematic diagram showing one embodiment of a photomask manufacturing method for reducing alignment error components EM generated in the photomask manufacturing process following FIG. 19. FIG. 5 is a schematic diagram showing distances D1 and D2 used to determine misalignment between transfer patterns in individual steps in a photomask manufacturing method performed using two photolithography steps.

  In the present invention, in the manufacture of a multilayer structure included in an electronic device, the idea is that the alignment error can be reduced if a photomask that can be patterned with a photomask in which a plurality of layers are formed by the same drawing process can be realized. did. That is, even if a single photomask has an alignment error component measured when compared with the design data of the photomask, a plurality of layers included in the stacked structure of the electronic device are respectively the same. If the patterning is performed using the photomask having the alignment error component, the alignment error component EM is effectively not manifested in the electronic device as the final product. That is, it is not impossible to theoretically set the EM component to zero.

  For example, even if it is difficult to manufacture a plurality of photomasks having the same alignment error tendency, it is a single photomask, and a transfer pattern defined by the same drawing process is added (if necessary, If a transferable photomask is used and applied to multiple layers, the alignment error tendency of the transfer pattern is the same. Therefore, the alignment error component EM should be substantially zero. Can do.

  Therefore, in the method for manufacturing an electronic device of the present invention, a first photomask is used for the step of forming a first thin film on a substrate and the first thin film or the first resist film formed on the first thin film. A first thin film pattern forming step of patterning the first thin film by performing a first photolithography process including a first exposure, and a second thin film on the substrate on which the first thin film pattern is formed. And performing a second photolithography process including a second exposure using a second photomask on the second thin film or the second resist film formed on the second thin film, And a second thin film pattern forming step of patterning the second thin film into a shape different from the first thin film pattern. In the method for manufacturing an electronic device of the present invention, the first photomask and the second photomask have a first transfer pattern including a light transmitting portion, a light shielding portion, and a semi-light transmitting portion, and The second photomask is the same photomask as the first photomask, or the second photomask is formed by performing an additional process on the first transfer pattern of the first photomask. The second transfer pattern is provided.

  The second photomask used in the method for manufacturing an electronic device of the present invention is the same photomask as the first photomask, or the second photomask is for the first transfer that the first photomask has. It has a second transfer pattern formed by performing additional processing on the pattern. That is, the first photomask and the second photomask are obtained by forming a transfer pattern in the same transfer region on the same transparent substrate. The second transfer pattern can be defined by a drawing process for forming the first transfer pattern by a method described later. Therefore, the alignment error component EM caused by the photomask used in the electronic device manufacturing process can be reduced. Incidentally, the transfer area refers to an area where the transfer pattern in the area is to be transferred onto the transfer target by exposure.

  In a conventional method for manufacturing an electronic device, a plurality of photomasks having different transfer patterns are used for a plurality of layers included in the electronic device, or one photomask having a plurality of transfer patterns. (Multi-tone photomask) was used. In any case, each of the plurality of transfer patterns includes a coordinate shift that occurs at the time of drawing, and this is manifested as an alignment error due to mutual overlay. As this alignment error component EM, there is no means for reducing the occurrence of about ± 0.5 μm, so this and an alignment error of about ± 0.6 μm caused by the exposure machine (EA) are added, and the maximum is about 1 μm. I had no choice but to accept the alignment error. The alignment error caused by the exposure machine is a total error of the reading accuracy of the alignment mark at the stage of mounting the photomask on the exposure machine and the mechanical accuracy of the stage set of the mask substrate in accordance with the reading. Theoretically, according to the present invention, alignment errors other than alignment errors caused by the exposure apparatus can be substantially eliminated.

  Here, the photolithography process uses a resist pattern obtained by exposing a photosensitive material (photoresist) film to a predetermined pattern and developing it as a mask, a thin film on the lower side of the resist film, etc. This is a series of processes for etching and forming a pattern.

  When etching is performed in the manufacturing process of the electronic device of the present invention, both dry etching and wet etching can be applied. In consideration of the isotropy of etching and the manufacturing cost, it is more preferable to apply wet etching. Similarly, in the mask manufacturing, it is more preferable to apply wet etching. When dry etching is applied, it is necessary to consider in advance the amount of resist (photosensitive material) that is reduced by etching a thin film.

  The photomask of the present invention is a photomask provided with a transfer pattern including a light shielding portion, a semi-translucent portion, and a translucent portion. This can be manufactured using a photomask blank in which a semi-transparent film and a light-shielding film are formed in this order on a transparent substrate, as will be described later in the configuration.

  In addition, as will be described later in the examples, there is a case where a photosensitive material is used as one of the laminated structures of the target electronic device, and there is a case where a material having no photosensitivity is used. Exists. For example, when the first thin film is a photosensitive material, the first thin film itself may be patterned by a photolithography process to form a target layer. On the other hand, when the first thin film is a non-photosensitive material, in order to pattern the first thin film, a resist film (photoresist film) is formed on the surface of the first thin film, and this is patterned to form an etching mask. The first thin film may be etched. The same applies to the second thin film. In this sense, the above description is expressed as “the first thin film or the first resist film formed on the first thin film”. That is, it means “a first thin film (when it is a film having photosensitivity) or a first resist film formed on the first thin film (when the first thin film has no photosensitivity)”.

  In the method of manufacturing an electronic device according to the aspect of the invention, the second photomask is the same photomask as the first photomask, and the light-shielding portion and the semi-transparent portion included in the first transfer pattern. It is included that the edge is defined by one drawing process. That is, when forming the first transfer pattern, it is not necessary to superimpose a plurality of drawing processes, and therefore, there is no occurrence of overlay deviation of patterns formed by different drawing processes.

  In the electronic device manufacturing method of the present invention, it is preferable that different conditions are applied to the first thin film pattern forming step and the second thin film pattern forming step.

  “Different conditions” include differences in resist (photosensitive material) films, differences in resist processes, differences in exposure conditions, and the like.

  Differences between the resist (photosensitive material) film and the resist process include the type of resist material used in each of the first thin film pattern forming step and the second thin film pattern forming step, and the resist development conditions (the composition, concentration, and concentration of the developer). Development time, etc.). Therefore, even when the first photomask and the second photomask are the same photomask, a second thin film pattern different from the first thin film pattern is formed using the same photomask. be able to. In addition, even when a second transfer pattern (also referred to as “additionally processed second transfer pattern”) formed by performing additional processing on the first transfer pattern of the first photomask is used, the first thin film is used. A second thin film pattern different from the pattern can be formed.

  Alternatively, as the difference in the above-described resist (photosensitive material) film, the first thin film or the first resist film and the second thin film or the second resist film have different coating film thicknesses. Can do.

  The difference in exposure conditions includes a case where application conditions of the first exposure and the second exposure are different. For example, the irradiation light quantity can be made different by applying different irradiation intensities of light sources or different irradiation times, which are applied to the first exposure and the second exposure. For example, the irradiation light quantity of the first exposure can be made larger than that of the second exposure or vice versa.

  In the electronic device manufacturing method of the present invention, it is preferable that the first thin film or the first resist film and the second thin film or the second resist film have different photosensitivities.

  “Different photosensitivity” is one of the differences in resist materials. For example, it may be a difference between a negative type and a positive type, or a difference in sensitivity characteristic (a difference in characteristic curve of photosensitivity with respect to the amount of light). There may be a difference in developability with respect to the developer. Since the first thin film or the first resist film and the second thin film or the second resist film have different photosensitivity, even when the same photomask or the photomask of the second transfer pattern that has been additionally processed is used. A second thin film pattern different from the first thin film pattern can be formed.

  In the electronic device manufacturing method of the present invention, the first thin film or the first resist film is made of a positive photosensitive material, and the second thin film or the second resist film is a negative photosensitive material. Can do. The first thin film or the first resist film is made of a positive photosensitive material, and the second thin film or the second resist film is a negative photosensitive material. Even when a photomask having a pattern is used, a second thin film pattern different from the first thin film pattern can be reliably formed.

  In the electronic device manufacturing method of the present invention, the first thin film or the first resist film is made of a negative photosensitive material, and the second thin film or the second resist film is a positive photosensitive material. Can do. The first thin film or the first resist film is made of a positive photosensitive material, and the second thin film or the second resist film is a negative photosensitive material. Even when a photomask having a pattern is used, a second thin film pattern different from the first thin film pattern can be reliably formed.

  In the method for manufacturing an electronic device according to the aspect of the invention, the second transfer pattern included in the second photomask is obtained by performing the additional processing on the first transfer pattern included in the first photomask, In the additional processing, the second transfer pattern can be formed by removing a part of the first transfer pattern.

  The second transfer pattern has a pattern edge formed as the pattern edge when the first transfer pattern is formed at the stage of manufacturing the first photomask. That is, even when a new drawing process is performed in the additional process for forming the second transfer pattern, a new pattern edge of the second transfer pattern is not formed in the new drawing process. That is, the drawing process performed in the second transfer pattern forming process does not have a function of forming the pattern edge of the second transfer pattern. The second transfer pattern may be an additional process for removing an isolated portion of the first transfer pattern. Therefore, the second transfer pattern is actually composed only of the one defined by one drawing, and this is the same time as the first transfer pattern drawing. Does not exist. Therefore, it is possible to reduce the alignment error component EM caused by the alignment error of the photomask used in the electronic device manufacturing process.

  In the method of manufacturing an electronic device according to the aspect of the invention, it is preferable that the first transfer pattern has a mark pattern having a line width that is not resolved by an exposure apparatus used when exposure is performed using the first photomask.

  In the additional processing, when the second transfer pattern is formed by removing a part of the first transfer pattern, the mark pattern can be used. That is, the mark pattern has a light-transmitting part (transparent part on which a semi-transparent film on a transparent substrate is exposed) or a light-transmitting part (transparent) that is sandwiched between light-shielding parts and is not resolved by an exposure apparatus. A portion where the substrate is exposed). In the additional processing, a part of the first transfer pattern on one side of the mark pattern can be removed with the mark pattern as a boundary. As a result, since the second transfer pattern is originally included in the first transfer pattern, there is no mutual drawing position shift between them. Therefore, the alignment error component EM can be reduced in the manufacturing process of the electronic device.

  In the above case where the photomask is formed using a mask blank having a semi-transparent film and a light-shielding film in this order on a transparent substrate, the mark pattern is removed in the shape of the mark pattern. Thus, a semi-translucent portion formed can be obtained. In this case, the mark pattern can be formed as a translucent portion formed by removing both the laminated semi-transparent film and the light-shielding film into the shape of the mark pattern. Since it is desirable that the mark pattern is not resolved during exposure (does not reach the resist exposure threshold), the former is preferable.

  If the line width of the mark pattern is too large, there arises a disadvantage that the mark pattern is resolved during the first exposure. On the other hand, if it is too small, it becomes difficult to absorb an alignment error with the first transfer pattern already formed on the photomask in a drawing process (described later) required for additional processing. Considering this point, the line width of the mark pattern is preferably 0.3 μm to 1.5 μm, and more preferably 0.3 to 1.0 μm.

  Here, the exposure apparatus is an exposure apparatus known as an LCD exposure apparatus or a liquid crystal exposure apparatus. For example, the NA (numerical aperture) of the optical system is 0.08 to 0.1, and σ (coherency). 0.8 to 0.9, and the minimum width (resolution limit) of the resolvable pattern can be about 3 μm. As exposure light, those including i-line, h-line, and g-line can be used.

  When performing additional machining, the first thin film or the first resist film and the second thin film or the second resist film can all be a positive photosensitive material. Also, the first thin film or the first resist film and the second thin film or the second resist film can all be negative photosensitive materials.

  The types of the first thin film and the second thin film can be appropriately selected depending on the type of electronic device to be manufactured. For example, the first thin film and the second thin film can be an electrode layer and an insulating layer, respectively.

  The photomask manufactured by the photomask manufacturing method of the present invention includes a first thin film pattern formed by patterning a first thin film and a second thin film pattern formed by patterning a second thin film on the same substrate. 1 is a photomask for manufacturing an electronic device having a stacked structure. This photomask is a photomask provided with a transfer pattern including a light shielding portion, a semi-translucent portion, and a translucent portion.

The method for producing a photomask of the present invention comprises:
A step of preparing a photomask blank in which a semi-transparent film and a light-shielding film are formed in this order on a transparent substrate;
A primary resist pattern for forming the light shielding portion and a provisional pattern that defines the semi-translucent portion by performing primary drawing on the primary resist film formed on the light shielding film. Forming a step;
A primary etching step of etching the light shielding film using the primary resist pattern as a mask;
Forming a secondary resist film on the entire surface including the formed light-shielding portion and the provisional pattern;
Forming a secondary resist pattern for forming the semi-translucent portion by performing secondary drawing on the secondary resist film;
A second etching step of etching the semi-translucent film using the temporary pattern and the second resist pattern as a mask;
And a third etching step of etching and removing the provisional pattern using the second resist pattern as a mask.
With the photomask manufacturing method of the present invention, a photomask capable of forming the first thin film pattern and the second thin film pattern of a desired electronic device can be manufactured using the same photomask. Then, an alignment error component EM caused by the transfer pattern of the photomask can be substantially not generated between these thin film patterns.

  In the above, “the semi-transparent film and the light shielding film are laminated in this order” does not only prevent the other films from intervening as long as the functions and effects of the present invention are not hindered. For example, when the etching characteristics of the semi-transparent film and the light shielding film are similar (etching selectivity is not sufficient), an etching stopper film may be interposed therebetween.

  Note that the expression of the first resist film, the first resist pattern, etc. in the above is distinguished from the first resist film and the first resist pattern used in the description of the process of manufacturing the electronic device. It is used for explanation.

  The photomask manufactured by the photomask manufacturing method of the present invention includes a first thin film pattern formed by patterning a first thin film and a second thin film pattern formed by patterning a second thin film on the same substrate. 1 is a photomask for manufacturing an electronic device having a stacked structure. The photomask includes a first transfer pattern for forming the first thin film pattern on a transparent substrate. The method of manufacturing a photomask of the present invention includes a step of preparing a photomask blank in which a semi-transparent film and a light-shielding film are formed in this order on the transparent substrate, and the semi-transparent film and the light-shielding film, respectively. Patterning by performing a photolithography process to form the first transfer pattern, and a first transfer pattern forming process. Here, the first transfer pattern has a shape for forming the first thin film pattern in the electronic device by exposure, and the line width is not resolved by the exposure apparatus used for the exposure. The shape includes the mark pattern. In the photomask of the present invention, the shape is formed by removing a part of the first transfer pattern, which is defined by the mark pattern, in order to form the second thin film pattern in the electronic device. It is possible to do.

  According to the photomask manufacturing method of the present invention, the first transfer pattern has a shape including a predetermined mark pattern, and a part of the first transfer pattern defined by the mark pattern is removed by additional processing. A photomask that can be manufactured can be manufactured. By using the photomask in the electronic device manufacturing method including the above-described predetermined additional process, it is possible to obtain an electronic device manufacturing method that can reduce the alignment error component EM caused by the photomask.

  In the photomask manufacturing method according to each aspect of the present invention, the photomask blank is formed by laminating the semi-transparent film and the light-shielding film having different etching characteristics on the transparent substrate in this order. preferable. The photomask blank is formed by laminating the semi-transparent film and the light-shielding film having different etching characteristics on the transparent substrate in this order, and is defined by a mark pattern. Part of the pattern can be easily removed by additional machining.

  That the etching characteristics are different from each other means that the other has resistance in one etching environment. Specifically, the light-shielding film and the semi-transparent film are preferably materials that are resistant to each other's etchant (etching solution or etching gas).

In the photomask of each aspect of the present invention and the photomask that can be used in the method of manufacturing the electronic device of each aspect of the present invention, specific examples of the material of the translucent film include a Cr compound (Cr oxide, Nitride, carbide, oxynitride, oxynitride carbide, etc.), Si compound (SiO ₂ , SOG), metal silicide compound (TaSi, MoSi, WSi or their nitride, oxynitride, etc.), TiON, etc. Ti compounds can be used.

  The material of the light-shielding film is Cr or Cr compound (Cr oxide, nitride, carbide, oxynitride, oxynitride carbide, etc.), Ta, Mo, W, or a compound thereof (including the above metal silicide), etc. Can be used.

  Therefore, considering each etching selectivity, for example, when a Si compound, a metal silicide compound, or a Ti compound is used for the semi-transparent film, the light shielding film material is preferably a combination of Cr or a Cr compound. The reverse combination is also possible.

  The light-shielding film and the semi-transparent film are preferably laminated so as not to substantially transmit the exposure light (optical density OD is 3 or more). However, depending on the use of the photomask, a part of the exposure light is used. Can be transmitted (for example, transmittance ≦ 20%). In the present specification, the light shielding film does not necessarily require complete light shielding properties. It is preferable that the optical density is OD3 or higher by lamination with a light-transmitting film. More preferably, it is preferable that only the light-shielding film has an optical density OD of 3 or more. For example, when the representative wavelength of the exposure wavelength is g-line, the OD can be for the representative wavelength.

  As the semi-transparent film, one having an exposure light transmittance of 20 to 80%, more preferably 30 to 70% and a phase shift amount of 90 ° or less, more preferably 60 ° or less is preferably used. Here, the exposure light transmittance is the transmittance of the semi-transparent film when the transmittance of the transparent substrate is 100%, and can be relative to the representative wavelength of light used for exposure. The phase shift amount of the semi-transparent film is a mutual phase difference between light transmitted through the transparent substrate and light transmitted through the semi-transparent film. The phase shift amount “90 degrees or less” means that the phase difference is “(2n−1 / 2) π to (2n + 1/2) π (where n is an integer)” in radians. To do.

  The exposure light used for transfer preferably includes a wavelength region including i-line, h-line, and g-line. As a result, even if the area of the transfer object is large (for example, a square having a side of 300 mm or more), the exposure can be performed without reducing the production efficiency. The representative wavelength of the exposure light may be any of i-line, h-line, and g-line, but may be g-line, for example. Preferably, the transmittance and the phase shift amount are satisfied for all of the i-line, h-line, and g-line.

  As the etchant (etching solution or etching gas) used for each film material, a known material can be used. In the case of a film containing Cr or a Cr compound (for example, a Cr light-shielding film having an antireflection layer made of Cr compound on its surface), it contains ceric ammonium nitrate, which is known as an etchant for chromium. An etchant can be used. Note that dry etching using a chlorine-based gas may be applied.

  Further, for a film of MoSi or a compound thereof, an etching solution obtained by adding an oxidizing agent such as hydrogen peroxide, nitric acid, sulfuric acid to a fluorine compound such as hydrofluoric acid, hydrosilicofluoric acid, or ammonium hydrogen fluoride. Can be used. Alternatively, a fluorine-based etching gas may be used.

  When a pattern is formed using these film materials, it is preferable to use wet etching in the step of removing the pattern by etching. Furthermore, it is more preferable to use wet etching in all etching processes.

  Next, a photomask that can be used in the method for manufacturing an electronic device of the present invention will be described. The photomask of the present invention manufactures an electronic device having a laminated structure in which a first thin film pattern obtained by patterning a first thin film and a second thin film pattern obtained by patterning a second thin film are laminated on the same substrate. It is a photomask for doing this. The photomask of the present invention includes a first transfer pattern for forming the first thin film pattern, in which the formed semi-transparent film and light shielding film are patterned on a transparent substrate. Here, the first transfer pattern has a shape for forming the first thin film pattern of the electronic device by exposure, and has a line width that is not resolved by the exposure apparatus used for the exposure. It has a shape including a mark pattern. The photomask of the present invention is configured such that a part of the first transfer pattern defined by the mark pattern is used as a second transfer pattern for forming the second thin film pattern of the electronic device. It can be removed by additional machining. Since the photomask of the present invention can remove part of the first transfer pattern by additional processing, the method for manufacturing an electronic device of the present invention including additional processing of the first transfer pattern, It can be used suitably.

  The second transfer pattern includes a translucent portion surrounded by a semi-transparent portion, a translucent portion surrounded by a light-shielding portion, a semi-transparent portion surrounded by the light-shielding portion, and a light-shielding surrounded by the semi-transparent portion. It is preferable to have any one of a part, the light-shielding part enclosed by the translucent part, and the semi-transparent part enclosed by the translucent part. As a result of the removal of a part of the first transfer pattern, the second transfer pattern created by the additional process of the present invention is formed as described above.

  The mark pattern preferably includes a semi-light-transmitting portion or a light-transmitting portion having a width of 0.3 to 1.5 μm that surrounds a part of the light-shielding portion of the first transfer pattern, and has a thickness of 0.3 to 1.0 μm. It is preferable to consist of a translucent part or a translucent part having a width. If the line width of the mark pattern is too large, there arises a disadvantage that the mark pattern is resolved during the first exposure. On the other hand, if it is too small, it becomes difficult to absorb an alignment error with the first transfer pattern already formed on the photomask in a drawing process required for additional machining. When the line width of the mark pattern is the predetermined width as described above, inconveniences and difficulties can be avoided. In addition, it is more preferable that the mark pattern is composed of a semi-translucent portion sandwiched between light-shielding portions because it is difficult to resolve during the first exposure.

  The present invention is a method for manufacturing a display device using the method for manufacturing an electronic device of the present invention. The “display device” includes a liquid crystal display device (LCD), a plasma display (PDP), an organic EL display device, and the like. According to the method for manufacturing an electronic device of the present invention, an electronic device such as an element such as a transistor, a diode, a capacitor, or a resistor, or a wiring can be formed with high accuracy by stacking various conductive films and insulating films. These electronic devices are applied to semiconductors such as integrated circuits, liquid crystal display devices, organic EL display devices, plasma displays, and the like. Therefore, the method for manufacturing an electronic device of the present invention can be suitably used when manufacturing a display device having these electronic devices.

  In a display device (including a liquid crystal display device, a plasma display, and an organic EL display device), the pattern becomes finer, the fine pattern tends to be arranged densely in a small area, and the number of stacked layers tends to increase. It has become prominent. Under such circumstances, the industrial significance of the present invention is further increased.

<Example 1>
FIG. 1 shows one mode of a photomask that can be used in the method for manufacturing an electronic device according to the first embodiment of the present invention. FIG. 1A shows the first transfer pattern including the light transmitting portion 11, the semi-light transmitting portion 12, and the light shielding portion 13, which the photomask has, in a plan view. As shown in FIG.

  The photomask shown in FIG. 1 prepares a photomask blank in which a semi-transparent film 20 and a light-shielding film 30 are formed in this order on a transparent substrate 10, and each of the semi-transparent film 20 and the light-shielding film 30 is prepared. It is formed by patterning through a photolithography process. Therefore, the transparent substrate 10 is exposed in the light transmitting portion 11, the semi-transmissive portion 12 is formed with the semi-transmissive film pattern 21 on the transparent substrate 10, and the light shielding portion 13 is shielded from the semi-transmissive film pattern 21. The film pattern 31 is laminated.

  Note that the stacking order of the semi-transparent film 20 and the light shielding film 30 may be reversed. In that case, after the light shielding film 30 formed on the transparent substrate 10 is patterned, the semi-transparent film 20 is formed and patterned to manufacture the photomask of the present invention.

  The light shielding film 30 applied to the photomask of the present invention may include an antireflection layer having an antireflection function on the surface. The same applies to the following embodiments.

  Here, as the transparent substrate 10 constituting the photomask, a quartz glass substrate whose surface is polished is used. The size is not particularly limited, and is appropriately selected according to a substrate to be exposed using the mask (for example, a flat panel display substrate). For example, a rectangular substrate having a side of 300 mm or more is used.

  In the photomask used in Example 1, the light shielding film 30 is made of Cr, and a surface provided with an antireflection layer of Cr oxide is used, and the semi-transparent film 20 is made of material. Used MoSi. That is, the light-shielding film 30 and the semi-transparent film 20 have etching selectivity with each other, and the other has resistance to the etching agent (etching solution or etching gas) of one film. It is suitable for manufacturing the photomask of FIG. When the etching selectivity is not obtained, an etching stopper film can be provided between the two films.

  FIG. 1 (c) shows a transmitted light amount on the alternate long and short dash line shown in FIG. 1 (a) when the photomask of the present invention as shown in FIG. 1 (a) is set in an exposure machine and irradiated with exposure light. Show the distribution. The resist film on the transferred body is irradiated with a light amount according to this distribution. A horizontal broken line shown in FIG. 1C indicates a photosensitivity threshold of the resist material. The same applies to the following examples.

  Below, the process of manufacturing the electronic device of Example 1 using this photomask is demonstrated using FIGS. 1-4.

  FIG. 2 shows a first thin film pattern forming process performed on the transfer target. Here, in the TFT array used in the display device, a contact hole 90 that connects the pixel electrode layer and the source / drain layer is formed (see FIG. 4C). However, the present invention is not limited to this application, and can be applied to the contact hole 90 connecting the upper layer side and the lower layer side in a multilayer structure wiring.

  The contact hole 90 may have a diameter of about 1.5 to 5 μm, and here is formed with a diameter of 2.5 μm and an insulating layer (for example, a passivation layer) of the electronic device to be obtained. Is done. The source / drain layer has a substantially square connecting portion with a side of 7 μm and a wiring portion connected to the connecting portion, and the contact hole 90 is designed in the center of the connecting portion. In addition, when the dimension of a connection part is the range which has about one side of about 3-10 micrometers, the effect of this invention is remarkable.

  As shown in FIG. 2A, first, a first resist film 40a is formed on a first thin film 60 formed on a substrate 50 (hereinafter also referred to as “device substrate 50”). The first resist film 40a is a positive resist. Then, the first resist film 40a is exposed using the photomask shown in FIG. 1 to transfer the first transfer pattern. As an exposure apparatus used for exposure, an exposure apparatus for LCD was used, and a light source including an i-line to g-line wavelength range was used. Next, the first resist film 40a was developed (FIG. 2 (b-1) plan view, FIG. 2 (b-2) sectional view). Here, resist patterns 41a having different resist residual film values are obtained in a region corresponding to the semi-transparent portion 12 of the photomask and a region corresponding to the light shielding portion 13. Then, the first thin film 60 is etched using the resist pattern 41a as an etching mask (FIG. 2C). That is, the first thin film 60 is removed leaving only the portion where the resist remains, and the first thin film pattern 61 is formed. The first thin film pattern 61 has a shape including a connection portion of the electronic device to be obtained. The first resist pattern 41a is peeled and removed (FIG. 2 (d-1) plan view, (d-2) sectional view).

  Next, the second thin film 70 is formed on the entire surface of the device substrate 50 including the obtained first thin film pattern 61 (FIG. 4A-1 plan view, FIG. 4A-2 cross-sectional view). Here, a second thin film 70b made of a photosensitive (negative type) material is used as the second thin film 70.

  Then, the second thin film 70b is patterned to form a second thin film pattern 71b. That is, using FIG. 3 (same as the photomask of FIG. 1), the first transfer pattern is exposed to the second thin film 70b. The same exposure machine as described above can be used. Then, as shown in FIGS. 4B-1 and 4B-2, the amount of light is adjusted so that the second thin film 70b in the region corresponding to the light-shielding portion 13 of the photomask has a blank pattern. As a result, a second thin film pattern 71b (contact hole pattern) having a fine diameter (about 1.5 to 5 μm) is formed in the second thin film 70b.

  Although the case where the second thin film 70 is photosensitive (negative type) has been described above, in the case of the second thin film 70 made of a material having no photosensitivity, the second resist film is formed on the second thin film 70. After forming a (negative type) and patterning the second resist film, the second thin film pattern may be formed by etching the second thin film using the obtained resist pattern as a mask.

  As is clear from the above, the same photomask is used for the patterning of the first thin film 60 and the second thin film 70 in spite of the patterning for making the patterns different from each other. That is, two exposures are performed using the same transfer pattern, but the pattern of the contact portion and the hole pattern can be formed in different layers due to different conditions of the thin film formation process.

  Here, it is assumed that the first transfer pattern of the photomask has a drawing deviation component generated in the manufacturing process (specifically, the drawing process). That is, the first transfer pattern may not completely match the two-dimensional pattern developed on the ideal coordinates shown in the drawing data. However, even if there is a deviation component from the virtual ideal coordinate at an arbitrary coordinate on the first transfer pattern, in the first thin film pattern 61 and the second thin film pattern 71, both of these coordinates are in the same direction. Since only the same amount of deviation occurs, no overlay deviation occurs between them.

  The first transfer pattern is a mask having the light-shielding part 13, the semi-translucent part 12, and the translucent part 11. In the manufacturing process, the drawing needs to be performed twice. In these two drawing steps, it is desired to prevent the misalignment between the drawn patterns (specifically, the semi-transparent film pattern 21 and the light shielding film pattern 31). That is, it is desirable that the edges of the semi-transmissive portion 12 and the light shielding portion 13 are defined by one drawing process. A method for manufacturing such a photomask will be described later.

  As described above, it is possible to manufacture an electronic device with extremely high overlay accuracy between the first thin film pattern 61 and the second thin film pattern 71 (FIG. 4C).

<Example 2>
In the second embodiment, as in the first embodiment, the first thin film 60 and the second thin film 70 are patterned using the same photomask to form an electronic device similar to the first embodiment. However, the first transfer pattern shape of the photomask and the photosensitivity of the first resist and the second thin film 70 formed on the transfer target are different from those of the first embodiment.

  As the first transfer pattern of the photomask used here, the pattern shown in FIG. 5 is used (this is the same as the photomask of FIG. 7 described later). 5A is a plan view, FIG. 5B is a cross-sectional view, and FIG. 5C shows a transmitted light amount distribution of exposure light.

  The photomask shown in FIG. 7 is a photomask blank in which a semi-transparent film 20 and a light-shielding film 30 are formed in this order on a transparent substrate 10 in the same manner as the photomask of the first embodiment. 20 and the light shielding film 30 are each formed by patterning by a photolithography process. Therefore, the transparent substrate 10 is exposed in the light transmitting portion 11, the semi-transmissive portion 12 is formed with the semi-transmissive film pattern 21 on the transparent substrate 10, and the light shielding portion 13 is shielded from the semi-transmissive film pattern 21. The film pattern 31 is laminated.

  Note that the order in which the semi-transparent film 20 and the light-shielding film 30 are stacked may be reversed as in the first embodiment. The materials of the light shielding film 30 and the semi-transparent film 20 were the same as those in Example 1.

  The process of manufacturing the electronic device of Example 2 using this photomask will be described with reference to FIGS. The first thin film pattern 61 and the second thin film pattern 71 to be formed are the same as those in the first embodiment. In the process, the same parts as those in Example 1 may be omitted.

  FIG. 6 shows a first thin film pattern forming step performed on the transfer target.

  As shown in FIG. 6A, first, a first resist film 40 b is formed on the first thin film 60 formed on the device substrate 50. The first resist film 40b is a negative resist. Then, the first resist film 40b is exposed using a photomask shown in FIG. 5 to transfer the first transfer pattern. The exposure apparatus is the same as that in the first embodiment.

  Next, the resist was developed (FIG. 6 (b-1) plan view, FIG. 6 (b-2) sectional view). Here, the first resist pattern 41b having different resist residual film values is obtained in the region corresponding to the semi-transparent portion 12 and the region corresponding to the transparent portion 11 of the photomask. Then, the first thin film 60 is etched using the first resist pattern 41b as an etching mask (FIG. 6C). That is, the first thin film 60 is removed leaving only the portion where the resist remains, and the first thin film pattern 61 is formed. The first thin film pattern 61 has a shape including a connection portion of the electronic device to be obtained. The first resist pattern 41b is peeled and removed (FIG. 6 (d-1) plan view, FIG. 6 (d-2) sectional view).

  Next, the 2nd thin film 70 is formed in the whole surface of the device substrate 50 containing the obtained 1st thin film pattern 61 (FIG. 8 (a-1) top view, FIG. 8 (a-2) sectional drawing). Here, the second thin film 70 a made of a photosensitive (positive type) material is used as the second thin film 70.

  Then, the second thin film 70a is patterned to form a second thin film pattern 71a. That is, using FIG. 7 (same as the photomask of FIG. 5), the first transfer pattern is exposed to the second thin film 70a. The exposure machine used is the same as described above. Then, as shown in FIGS. 8B-1 and 8B-2, the second thin film 70a in the region corresponding to the light-shielding portion 13 of the photomask becomes a blank pattern.

  As in Example 1, when the second thin film 70 is a material having no photosensitivity, a second resist film (positive type) is formed on the second thin film. After the patterning, the second thin film may be formed by etching the second thin film using the obtained resist pattern as a mask.

  As is apparent from the above, even in the second embodiment, the first thin film 60 and the second thin film 70a are patterned to form patterns having different shapes, but the same photomask is used. . For this reason, it is possible to manufacture an electronic device in which the overlay accuracy of the first thin film pattern 61 and the second thin film pattern 71a is extremely high (FIG. 8C).

<Reference example>
Note that the photomask used in Examples 1 and 2 includes a light-shielding part 11, a semi-translucent part 12, and a transfer pattern including the translucent part 11 (FIGS. 1A and 5A). (See Fig.) So-called multi-tone photomask. In the process of manufacturing such a photomask, as mentioned above, the photolithography process is applied to the semi-transparent film and the light-shielding film formed on the substrate, respectively, to perform patterning. However, there is a risk that the photomask itself will have an alignment error component EM if a positional deviation occurs in the drawing process in these two photolithography.

  In this regard, the present inventor has found that a multi-tone photomask that does not cause misalignment in two photolithography processes can be manufactured by the following method.

Mask manufacturing method 1 without an alignment error is:
A method for producing a photomask having a transfer pattern provided on a transparent substrate by laminating a lower layer film pattern and an upper layer film pattern obtained by patterning a lower layer film and an upper layer film having different exposure light transmittances, respectively. And
A step of laminating the lower layer film and the upper layer film made of materials having etching selectivity on the transparent substrate, and preparing a photomask blank in which a first resist film is formed; and the first resist Forming a primary resist pattern for forming the upper layer film pattern and a provisional pattern that defines a region of the lower layer film pattern by performing primary drawing on the film; and
A first etching step of etching the upper layer film using the first resist pattern as a mask;
Forming a secondary resist film on the entire surface including the formed upper layer film pattern and the provisional pattern;
Forming a second resist pattern for forming the lower layer film pattern by performing second drawing on the second resist film;
Etching the lower layer film using the temporary pattern and the second resist pattern as a mask, a second etching step,
And a third etching step of etching and removing the provisional pattern using the second resist pattern as a mask.

  More specifically, the mask manufacturing method 1 having no alignment error can be used as a mask manufacturing method 2 having no alignment error as described below.

Mask manufacturing method 2 without alignment error is:
A method for producing a photomask comprising a transfer pattern including a light shielding part, a semi-translucent part, and a translucent part,
A step of laminating a semi-transparent film and a light-shielding film made of materials having etching selectivity on a transparent substrate, and further preparing a photomask blank in which a primary resist film is formed;
Forming a primary resist pattern for forming the light-shielding portion and a provisional pattern defining the semi-translucent portion by performing primary drawing on the primary resist film; A primary etching step of etching the light shielding film using the primary resist pattern as a mask;
Forming a secondary resist film on the entire surface including the formed light-shielding portion and the provisional pattern;
Forming a secondary resist pattern for forming the semi-translucent portion by performing secondary drawing on the secondary resist film;
A second etching step of etching the semi-translucent film using the temporary pattern and the second resist pattern as a mask;
And a third etching step of etching and removing the provisional pattern using the second resist pattern as a mask.

In the above two methods (mask manufacturing methods (1) and (2) with no alignment error), it is preferable to further perform the following.
(1) In the secondary resist pattern forming step, the secondary drawing is performed so that a part of the temporary pattern is exposed from an edge of the secondary resist pattern;
In the temporary pattern etching removal step, wet etching is performed on the temporary pattern partially exposed from the edge of the second resist pattern.
(2) The width of the temporary pattern is 2 μm or less.
(3) The transfer pattern is a hole pattern or a dot pattern.
(4) In the second resist pattern forming step, the second drawing is performed so that the edge on the light transmitting portion side of the temporary pattern is exposed with a width of 0.1 to 1.0 μm. It is characterized by.

  Embodiments of such a photomask manufacturing method will be described with reference to FIGS.

  The photomask transfer pattern formed here can be as shown in FIG. In order to evaluate whether or not an alignment error between the light-shielding portion and the semi-transparent portion (as a result of course, the translucent portion) included in the transfer pattern occurs, D1 and D2 shown in FIG. It can be determined using the dimensions. In the reference embodiment described below, FIG. 21A shows a transfer pattern having a semi-transparent portion surrounded by a translucent portion and a light-shielding portion surrounded by the semi-transparent portion. The method of manufacturing without producing is shown.

  19 and 20, a case where a semi-transparent portion is formed as a lower layer film pattern and a light shielding portion is formed as an upper layer film pattern will be described as an example. In FIGS. 19 and 20, a plan view is shown on the upper side, and a cross-sectional view is shown on the lower side. Furthermore, when the resist film is in the uppermost layer, it is schematically depicted so that the light shielding film hidden underneath can be seen through.

  First, as shown in FIGS. 19A to 19C and FIG. 20D, a primary photolithography process for patterning the light shielding film is performed.

  In FIG. 19, first, a photomask blank in which a semi-transparent film and a light-shielding film are laminated in this order on a transparent substrate, and a primary resist film (here made of a positive resist) is further formed thereon. Is prepared (see FIG. 19A). Here, it is assumed that the semi-transparent film and the light shielding film have etching selectivity. That is, the light-shielding film is resistant to the etchant of the semi-transparent film, and the semi-transparent film is resistant to the etchant of the light-shielding film. In addition, about a specific material, it can be set as the above-mentioned thing.

  Next, primary drawing is performed and developed to form a primary resist pattern. This primary resist pattern defines a region of the light shielding portion. Further, a portion for forming a temporary pattern made of a light-shielding film that defines the outer edge of the semi-translucent portion in the region to be the semi-translucent portion is also included in the primary resist pattern (FIG. 19B). reference).

  This temporary pattern is removed by etching in a later process. Preferably, it is preferably removed by wet etching which has an excellent effect of isotropic etching. Therefore, it is desirable that the width of the provisional pattern be a width that can be reliably removed without taking excessive time for the removal process. Specifically, the width is preferably 2 μm or less.

  Furthermore, this provisional pattern can absorb the amount of misalignment resulting from two drawing steps. Therefore, it is desirable to determine based on the size of the misalignment that can occur. Therefore, assuming that the maximum value of misalignment is ± 0.5 μm, the width of the temporary pattern is preferably 0.5 to 2 μm, more preferably 0.5 to 1.5 μm, and even more preferably 0.5 to 1.0 μm is preferred.

  Since the primary resist pattern includes the portion for forming the light shielding portion and the portion for forming the temporary pattern as described above, the drawing data for the primary drawing is determined based on this. .

  As described above, by appropriately determining the width of the provisional pattern according to the maximum value of the misalignment (for example, 2 μm or less), in the etching process (third etching process) for removing the provisional pattern, excessive time or Since no labor is required, efficient photomask manufacturing can be realized.

  Next, the light shielding film is etched using the first resist pattern as an etching mask (first etching). Here, the region of the light shielding part is defined, and further, the outer edge of the semi-translucent part to be patterned later is defined by the provisional pattern (see FIG. 19C). Subsequently, proceeding to FIG. 20, the primary resist pattern is peeled off. (See FIG. 20D) Thus, the first photolithography process for patterning the light shielding film is completed.

  Next, a resist film is applied again over the entire surface of the substrate (see FIG. 20E). Then, secondary drawing and development are performed to form a secondary resist pattern (see FIG. 20F). This secondary resist pattern exposes a portion that becomes a translucent portion.

  Since the second resist pattern is formed by a drawing process different from the drawing process when forming the first resist pattern, the second resist pattern is formed with a positional deviation of zero with respect to the position of the first resist pattern. It is virtually impossible to do. However, according to the present invention, the deviation from the design value can be made zero in the final transfer pattern to be formed in spite of this alignment variation.

  In other words, the second resist pattern exposes a region to be a translucent part and covers a region to be a semi-translucent part. A resist pattern having a size smaller by a predetermined margin dimension (for example, 0.1 to 1.0 μm, more preferably 0.2 to 0.8 μm) corresponding to the width of the provisional pattern is formed on the light transmitting portion side. That is, the edge of the resist pattern is moved backward to the semi-translucent portion side (left side in the section JJ in FIG. For this reason, the edge (or at least the side surface on the light transmitting portion side) of the provisional pattern is slightly exposed from the edge of the secondary resist pattern (see FIG. 20F).

  Therefore, drawing data taking this point into consideration is used in the second drawing. For example, the secondary resist pattern can be formed with a design in which the edge of the resist pattern is located at the center of the width of the provisional pattern.

  As described above, the edge on the light transmitting portion side of the temporary pattern is exposed with a predetermined width (for example, 0.1 to 1.0 μm), thereby ensuring misalignment between different photolithography processes. In addition to being able to absorb, it is possible to avoid excessive time and labor in the etching process (third etching process) for removing the temporary pattern.

  Since the edge on the light transmitting portion side of the provisional pattern is a portion that becomes an accurate outer edge of the semi-light transmitting portion defined in the first etching process, this portion is used as an etching mask together with the second resist pattern. Then, the semi-transparent film is etched (secondary etching) using an etchant of the semi-transparent film (see FIG. 20G). Here, since the temporary pattern is formed by the light shielding film, it does not disappear even if it contacts the etchant of the semi-transparent film.

  Next, the temporary pattern is removed using the etchant of the light-shielding film with the second resist pattern remaining (third etching process). Note that the already formed light-shielding portion is protected by the secondary resist pattern, so that it is not damaged when the provisional pattern is removed. Here, since it is effective to perform side etching from the side surface of the provisional pattern, it is preferable to use wet etching, which is superior in action of isotropic etching, not dry etching. Then, the provisional pattern is lost. At this time, the semi-transparent film is resistant to the etchant of the light-shielding film and thus does not disappear (see FIG. 20H). Finally, the secondary resist pattern is peeled off (see FIG. 20I).

  As described above, in the photomask obtained by the steps shown in FIGS. 19 and 20, the light shielding portion is arranged at the center of the semi-translucent portion as designed. That is, the edge of the light-shielding film pattern and the semi-transparent film pattern formed in different drawing processes shifts in the X direction and the Y direction, so that the conventional inconvenience does not occur and the position is as designed.

  Even if a relative positional deviation from the primary drawing occurs during the secondary drawing, a part of the provisional pattern is at least partially exposed from the edge of the secondary resist pattern. In other words, the dimensions of the temporary pattern are selected so that the side surface of the temporary pattern is exposed from the edge of the secondary resist pattern even when the relative positional deviation occurs. Therefore, the outer edge of the semi-translucent portion can be surely defined by the temporary pattern, so that the arrangement as designed formed by the first resist pattern can be realized. Further, the light-shielding portion is protected by the secondary resist pattern, and the temporary pattern can be removed by etching (third etching process) without affecting the semi-transparent portion due to the etching selectivity. No further photolithography process is required. In order to remove the temporary pattern, the photolithography process may be repeated once more.

  As described above, according to the present invention, in a photomask that requires a plurality of drawing operations, the alignment of each region provided in the transfer pattern is accurately performed, and furthermore, the transfer that can suppress the number of times the photolithography process is performed. The manufacturing method of a photomask provided with the pattern for use can be provided.

  In addition, a portion of the temporary pattern is formed so as to be exposed from the edge of the secondary resist pattern, and the entire temporary pattern is removed by the action of isotropic etching that wet etching has on the temporary pattern that is partially exposed. can do. Therefore, the number of executions of the photolithography process can be reliably suppressed.

In the present invention, the first transfer pattern of the multi-tone photomask described in Example 1 and Example 2 can be formed by the method described in the above reference example. In this case, the edges of the light shielding part and the semi-translucent part included in the first transfer pattern are both demarcated by the primary drawing. Thereby, alignment of each area | region with which the pattern for transcription | transfer is performed is performed correctly, Furthermore, the manufacturing method of a photomask provided with the pattern for transcription | transfer which can suppress the frequency | count of execution of a photolithography process can be provided.
<Example 3>
FIG. 9 is a photomask according to another aspect of the present invention, and shows an example of a photomask used in the process of manufacturing the electronic device of Example 3.

  This photomask is a first transfer pattern obtained by forming a semi-transparent film 20 on a transparent substrate 10 and further preparing a photomask blank on which a light shielding film 30 is formed, and patterning the light shielding film 30. Prepare. The film material is the same as in Example 1.

  This first transfer pattern is for forming the first thin film pattern 61, and forms the connection portion in the source / drain layer, while the second thin film pattern 61 is formed by performing additional processing after the first thin film pattern 61 is formed. It can be a second transfer pattern used for forming the thin film pattern 71.

  The first transfer pattern has a light shielding portion 13 and a semi-transparent portion 12. A slit-like semi-transparent portion 12 (mark pattern 80) having a fine width (here, 1 μm in width) is formed in the region of the light-shielding portion 13, and is surrounded by the slit-like semi-transparent portion 12. The light-shielding part 13 exists (FIG. 9 (a) top view, (b) sectional drawing). In this embodiment, the slit-like semi-transparent portion 12 has a shape corresponding to the outer periphery of the contact hole pattern of the electronic device to be obtained, and has a quadrangular shape that surrounds the contact hole pattern with a width of 1 μm. Yes.

  The mark pattern 80 is formed as a semi-translucent portion, but may be formed as a translucent portion. The former is more preferable because it is difficult to resolve.

  Below, the process of manufacturing the electronic device of Example 3 similar to Example 1 using this photomask is demonstrated using FIGS. However, the second embodiment is different from the first embodiment in that the photomask used in the first thin film pattern forming process is additionally processed and used in the second thin film pattern forming process.

  FIG. 10 shows a first thin film pattern forming step. As shown in FIG. 10A, first, a first resist film 40 a is formed on the first thin film 60 formed on the device substrate 50. The first resist film 40a is a positive resist. Then, the first resist film 40a is exposed using a photomask shown in FIG. 9 to transfer the first transfer pattern. Although the same exposure apparatus as that in Example 1 can be used, it is preferable to increase the amount of light irradiated to the photomask by extending the exposure time by a predetermined amount. Next, the resist was developed (FIG. 10 (b-1) plan view, FIG. 2 (b-2) sectional view).

  Here, since the irradiation light quantity is increased, the first resist film 40a in the region corresponding to the semi-transparent portion 12 of the photomask is sufficiently exposed and eluted by development. On the other hand, in the first resist film 40a in the region corresponding to the light shielding portion 13, a first resist pattern 41a in which a predetermined remaining film remained was formed. The semi-transparent portion 12 having a width of 1 μm has a line width less than the resolution limit of the exposure apparatus. Therefore, the first resist film 40a can hardly be reduced and is not substantially transferred.

  Then, the first thin film 60 is etched using the first resist pattern 41a as an etching mask (FIG. 10C). That is, the first thin film 60 is removed leaving only the portion where the resist remains, and the first thin film pattern 61 is formed. The first thin film pattern 61 has a shape including a connection portion of the electronic device to be obtained. The first resist pattern 41a is peeled and removed (FIG. 10 (d-1) plan view, (d-2) sectional view).

  Next, the second thin film 70 is formed on the entire surface of the device substrate 50 including the obtained first thin film pattern 61 (FIG. 12A-1 plan view, FIG. 12A-2 cross-sectional view). Here, the second thin film 70 a made of a photosensitive (positive type) material is used as the second thin film 70.

  Then, the second thin film 70a is patterned to form a second thin film pattern 71a. At this time, the photomask of FIG. 11 obtained by performing additional processing on the photomask of FIG. 9 is used. This additional processing removes the light-shielding portion 13 at a position surrounded by the semi-light-transmitting portion 12 formed in a slit shape with a fine width and converts it to the light-transmitting portion 11. That is, the light-shielding film 30 forming the light-shielding part 13 surrounded by the slit-like semi-transparent part 12 is removed by etching, and the semi-transparent film 20 exposed there is also removed by etching. And the transparent part 11 which the transparent substrate 10 exposed is formed. The translucent portion 11 has a shape and a size for forming a hole pattern in an electronic device. The details of the additional process will be described later.

  Through the above-described additional processing, the first transfer pattern of the photomask in FIG. 9 is converted into the second transfer pattern of the photomask in FIG. However, since the edge of the light-shielding portion 13 in the second transfer pattern is an edge existing in the first transfer pattern (including an edge adjacent to the semi-translucent portion 12 having a small width), the second transfer The edge of the pattern (especially the edge of the light shielding portion 13) of the pattern is not an edge newly formed in the process of conversion.

  When transferring the second transfer pattern to the second thin film 70a, the same exposure machine as described above can be used. Then, as shown in FIGS. 12B-1 and 12B-2, the amount of light is adjusted so that the second thin film 70a in the region corresponding to the light-transmitting portion 11 of the photomask has a blank pattern. Thereby, the second thin film pattern 71a (contact hole pattern) is formed.

  Although the case where the second thin film 70 is photosensitive (positive type) has been described above, in the case of the second thin film 70 made of a material having no photosensitivity, the second resist is formed on the second thin film 70. As in the first embodiment, a film (positive type) may be formed and a photolithography process may be performed.

  As is clear from the above, the patterning of the first thin film 60 and the second thin film 70 is patterning for making patterns having different shapes. Nevertheless, the transfer pattern on the photomask used for the patterning was transformed by additional processing, but was defined by only one photolithography process (ie, one writing process). This is a transfer pattern. For this reason, even if the first transfer pattern of the photomask includes a drawing deviation component generated in the manufacturing process (drawing process), in the first thin film pattern 61 and the second thin film pattern 71, Since the components are the same, alignment errors due to superposition do not occur.

  As a result, it is possible to manufacture an electronic device with extremely high overlay accuracy between the first thin film pattern 61 and the second thin film pattern 71 (FIG. 4C).

<Example 4>
The additional processing of the photomask performed in Example 3 will be described as Example 4.

  FIG. 13 ((a-1) plan view, (a-2) cross-sectional view) is a photomask having a first transfer pattern used in Example 3. FIG. After the first thin film pattern forming step, a light shielding film of a light shielding portion 13 (hereinafter also referred to as a removal pattern) surrounded by a mark pattern composed of a semi-transparent portion having a fine width, and a semi-transparent film on the lower layer side thereof Need to be removed. This step can be performed as follows.

  First, a resist is applied to the entire surface of the transparent substrate 10 including the first transfer pattern to form a resist film 45 for additional processing (FIG. 13 (b-1) plan view, (b-2) sectional view). Next, drawing is performed using a drawing machine, and development is performed, so that a removal pattern portion is exposed and an additional processing resist pattern 46 covering the other light shielding portion 13 is formed (FIG. 13C).

  At this time, as the drawing pattern, it is necessary to reliably cover the light shielding portion 13 of the portion other than the removal pattern. However, even if drawing is performed such that the edge position of the resist pattern 46 for additional processing coincides with the dimension of the light shielding portion 13 other than the removal pattern, on the same transparent substrate 10 on which the first transfer pattern has already been drawn, Since the drawing is newly performed, there is a risk that the edge positions are not exactly matched due to the mutual shift due to the overlay. If there is a shift in the edge position, the light shielding portion 13 other than the removal pattern (that is, the edge of the light shielding portion 13 in the second transfer pattern) is partially exposed from the additional processing resist pattern 46 and eluted during etching. There is a possibility that.

  Therefore, the drawing data is adjusted so that the edge position of the additional processing resist pattern 46 to be formed is within the region of the slit-shaped semi-translucent portion 12 having a fine width. Incidentally, since the coordinate deviation caused by the drawing machine is about 0.5 μm at the maximum, if the semi-transparent portion 12 having a fine width is 1 μm wide, the edge of the resist pattern 46 for additional processing is surely attached to its half. It can be positioned within the line width of the translucent part 12 (mark pattern 80). FIG. 13C shows a state where the additional processing resist pattern 46 has entered the inside of the semi-transparent portion 12 having a fine width by a distance d1.

  For this reason, as the drawing data, sizing is performed so that the edge of the resist pattern 46 for additional processing is expanded by 0.5 μm toward the removal pattern (adding an alignment margin of 0.5 μm). That is, in this portion, drawing is performed such that the size is shifted by 0.5 μm toward the fine width semi-translucent portion 12 from the design dimension of the second transfer pattern.

  Accordingly, the removal pattern is surely exposed from the additional processing resist pattern 46, while the light shielding portion 13 other than the removal pattern (the light shielding portion 13 of the second transfer pattern) is reliably covered with the additional processing resist pattern 46. .

  Note that the size of this sizing can be determined in consideration of the size of the coordinate deviation component of the drawing machine. However, if the maximum value of the coordinate deviation is ± X μm (for example, ± 5 μm), the sizing may be set to X μm (for example, 5 μm). However, this dimension leads to the width of the fine translucent portion 12 to be formed in the first transfer pattern being 2 × μm. If the width of the semi-translucent portion 12 is too large, the line width approaches the resolvable line width by the exposure machine. Therefore, it can be said here that X is preferably about 0.3 to 0.8 μm.

  Next, the removed pattern is removed by etching using the formed additional processing resist pattern 46 as an etching mask (FIG. 13D). Here, an etching agent for the light shielding film material (if the light shielding film material is mainly composed of Cr, an etching agent for Cr) is used.

  Thereafter, etching is performed to remove the exposed semi-transparent film 20 (FIG. 13E). For example, if the semi-transparent film 20 is mainly composed of MoSi, an etching agent for MoSi is used. At this time, it is preferable to remove the translucent film 20 by changing only the etching agent without removing the resist pattern 46 for additional processing used for etching the light shielding film 30.

  At this time, as shown in FIG. 13 (e), the edge of the resist pattern 46 for additional processing is increased by 0.5 μm after the above sizing, so that the translucent portion 11 in the second transfer pattern is semi-transmissive. There may be a risk that a part of the optical film 20 remains. However, if wet etching is applied to the etching of the semi-transparent portion 12, the semi-transparent film 20 is sufficiently etched by the side etching as shown in FIG. Furthermore, if over-etching is performed, the light shielding portion 13 for forming the contact hole pattern can be obtained more reliably. This suggests the possibility that the problem of the present invention, which attempts to reduce the alignment error of the electronic device to be obtained, may reach a higher level.

  That is, as verified in Examples 1 to 3, if the alignment error EM component caused by the photomask can theoretically be zero, an alignment error of the finally obtained electronic device cannot be considered conventionally. It can be compressed to a certain extent.

<Example 5>
Still another aspect of the additional processing of the photomask performed in Example 3 will be described as Example 5.

  FIG. 14 ((a-1) plan view, (a-2) cross-sectional view) is a photomask having a first transfer pattern used in Example 3. FIG. After the first thin film pattern forming step, the light-shielding film of the light-shielding portion 13 (hereinafter also referred to as “removal pattern”) surrounded by a mark pattern composed of a semi-transparent portion having a fine width and the semi-light-transmitting layer on the lower layer side thereof The film needs to be removed. This step can be performed as follows.

  First, as in Example 4, a resist is applied to the entire surface of the transparent substrate 10 including the first transfer pattern to form a resist film 45 for additional processing (FIG. 14B-1 plan view, FIG. -2) Cross-sectional view). Next, in the same manner as in Example 4, drawing is performed using a drawing machine, and development is performed, so that the removal pattern portion is exposed, and an additional processing resist pattern 46 that covers the other light shielding portion 13 is formed (see FIG. 14 (c)).

  Next, similarly to Example 4, the removal pattern is removed by etching using the formed additional processing resist pattern 46 as an etching mask (FIG. 14D). Here, an etching agent for the light shielding film material (if the light shielding film material is mainly composed of Cr, an etching agent for Cr) is used.

  Next, in the additional processing of the photomask of Example 5, the additional processing resist pattern 46 is peeled off (FIG. 14E). Thereafter, the semi-transparent film 20 is partially removed to form the translucent portion 11 in the second transfer pattern.

  Specifically, as shown in FIG. 14F, a new additional processing resist film 47 is formed on the entire surface of the photomask, and further, drawing is performed using a drawing machine. In this drawing data, sizing is performed such that the edge of the resist pattern 48 for additional processing recedes by 0.5 μm with respect to the edge position of the light-shielding portion 13 of the second transfer pattern (the alignment margin is 0.5 μm). (FIG. 14 (g)). As a result, as shown in FIG. 14G, the edge of the additional processing resist pattern 48 moves backward by d2 from the edge of the light shielding portion 13. If the semi-transparent film 20 is etched using the additional processing resist pattern 48 thus formed as a mask, the edge of the light shielding portion 13 already formed as the first transfer pattern functions as an etching mask. Therefore, only the semi-transparent film 20 on the lower layer side is removed, and the hole pattern in the second transfer pattern is accurately formed.

  That is, in Example 4 and Example 5, the alignment error component (EM) resulting from the superimposition of the photomask pattern due to this new drawing is increased despite the increase in the number of drawing steps due to the additional processing of the photomask. It shows a method that does not occur.

<Comparative Example 1>
A method for manufacturing an electronic device similar to that of the first embodiment by a conventional method will be described with reference to FIGS.

  FIG. 15A shows a pattern obtained by patterning the light shielding film 30 formed on the transparent substrate 10 by a known method, and includes a light shielding part 13 (first transfer pattern) including a connecting part. Let this binary mask be Mask A.

  Using this, a connection portion is first formed on the device substrate 50. That is, as shown in FIG. 16A-1, a first thin film 60 is formed on the device substrate 50, and a first resist film 40a (positive type) is further formed. Then, using Mask A, the first transfer pattern is exposed by an exposure machine. The exposure machine is the same as in the above embodiment. Then, as shown in FIGS. 16B-1 and 16B-2, the first resist film 40a is developed, and the first thin film 60 is etched using the obtained first resist pattern 41a as a mask (FIG. 16 (c)).

  When the first resist pattern 41a is peeled off, the first thin film pattern 61 having the connecting portion shown in FIGS. 16 (d-1) and (d-2) is completed.

  Next, the second thin film 70 a is formed on the entire surface of the device substrate 50 including the first thin film pattern 61. The second thin film 70a is composed of a second thin film 70a made of a positive photosensitive material (FIG. 18 (a-1) plan view, FIG. 18 (a-2) sectional view).

  Then, exposure is performed by an exposure device using a second mask (Mask B) shown in FIG. Mask B is a binary mask provided with a second transfer pattern for forming a hole pattern.

  When developed after exposure, a contact hole 90 is formed in the second thin film 70a (FIG. 18C).

  However, Mask A and Mask B are photomasks formed in different processes, respectively, and the tendency of coordinate deviations that occurred in the photolithography process (particularly the drawing process) performed in each manufacturing process is the same. Even if the drawing machine is used, it does not match completely. FIG. 18C shows a state in which a coordinate shift of Δx in the x direction and Δy in the y direction has occurred.

  For example, if an arbitrary coordinate on the first transfer pattern of Mask A is shifted to a position of + M μm with respect to a design coordinate and Mask B is shifted to a position of −M μm, an alignment error that occurs at the time of overlay is as follows. 2M μm. That is, in the electronic device manufactured by this method, it is inevitable that the EM component of the alignment error resulting from the superposition of the two patterns deteriorates the accuracy of the electronic device (FIG. 18C). .

DESCRIPTION OF SYMBOLS 10 Transparent substrate 11 Translucent part 12 Semi-transparent part 13 Light-shielding part 15 Alignment mark 20 Semi-transparent film 21 Semi-transparent film pattern 30 Light-shielding film 31 Light-shielding film pattern 40a 1st resist film (positive type)
40b First resist film (negative type)
41a First resist pattern (positive type)
41b First resist pattern (negative type)
45 Additional processing resist film 46 Additional processing resist pattern 47 Additional processing resist film 48 Additional processing resist pattern 50 Device substrate 60 First thin film 61 First thin film pattern 70 Second thin film 70a Second thin film (positive type)
70b Second thin film (negative type)
71 2nd thin film pattern 71a 2nd thin film pattern (positive type)
71b Second thin film pattern (negative type)
80 Mark pattern 90 Contact hole

Claims (15)

In a method for manufacturing an electronic device,
Forming a first thin film on the substrate;
The first thin film is patterned by subjecting the first thin film or the first resist film formed on the first thin film to a first photolithography process including a first exposure using a first photomask. A first thin film pattern forming step;
Forming a second thin film on the substrate on which the first thin film pattern is formed;
The second thin film or the second resist film formed on the second thin film is subjected to a second photolithography process including a second exposure using a second photomask, whereby the second thin film is converted into the first thin film. Patterning into a shape different from the one thin film pattern, a second thin film pattern forming step;
Have
The first photomask and the second photomask have a first transfer pattern including a light transmitting portion, a light shielding portion, and a semi-light transmitting portion, and
The second photomask is the same photomask as the first photomask, or the second photomask is formed by performing an additional process on the first transfer pattern of the first photomask. A method for manufacturing an electronic device, comprising the second transfer pattern.   The second photomask is the same photomask as the first photomask, and the light shielding part and the edge of the semi-translucent part included in the first transfer pattern are defined by one drawing process. The method of manufacturing an electronic device according to claim 1, wherein the electronic device is manufactured.   The method for manufacturing an electronic device according to claim 1, wherein different conditions are applied in the first thin film pattern forming step and the second thin film pattern forming step.   The electron according to claim 1, wherein the first thin film or the first resist film and the second thin film or the second resist film have different photosensitivities. Device manufacturing method.   The first thin film or the first resist film is made of a positive photosensitive material, and the second thin film or the second resist film is a negative photosensitive material. The manufacturing method of the electronic device of any one of these.   The first thin film or the first resist film is made of a negative photosensitive material, and the second thin film or the second resist film is a positive photosensitive material. The manufacturing method of the electronic device of any one of these.   The second transfer pattern of the second photomask is obtained by performing the additional processing on the first transfer pattern of the first photomask, and the additional processing is performed by using the first transfer pattern. The method for manufacturing an electronic device according to claim 1, wherein the second transfer pattern is formed by removing a part of the pattern.   8. The electronic device according to claim 7, wherein the first transfer pattern has a mark pattern having a line width that is not resolved by an exposure apparatus used when exposure is performed using the first photomask. 9. Manufacturing method. A photomask for manufacturing an electronic device having a laminated structure in which a first thin film pattern obtained by patterning a first thin film and a second thin film pattern obtained by patterning a second thin film are laminated on the same substrate. A manufacturing method of
The photomask has a transfer pattern that is formed on a transparent substrate and includes a light shielding portion, a semi-translucent portion, and a translucent portion,
A step of preparing a photomask blank in which a semi-transparent film and a light-shielding film are formed in this order on a transparent substrate;
A primary resist pattern for forming the light shielding portion and a provisional pattern that defines the semi-translucent portion by performing primary drawing on the primary resist film formed on the light shielding film. Forming a step;
A primary etching step of etching the light shielding film using the primary resist pattern as a mask;
Forming a secondary resist film on the entire surface including the formed light-shielding portion and the provisional pattern;
Forming a secondary resist pattern for forming the semi-translucent portion by performing secondary drawing on the secondary resist film;
A second etching step of etching the semi-translucent film using the temporary pattern and the second resist pattern as a mask;
And a third etching step of etching and removing the provisional pattern using the second resist pattern as a mask. A photomask for manufacturing an electronic device having a laminated structure in which a first thin film pattern obtained by patterning a first thin film and a second thin film pattern obtained by patterning a second thin film are laminated on the same substrate. A manufacturing method of
The photomask includes a first transfer pattern for forming the first thin film pattern on a transparent substrate,
A step of preparing a photomask blank in which a semi-transparent film and a light-shielding film are formed in this order on the transparent substrate;
Patterning the semi-translucent film and the light-shielding film by performing a photolithography process to form the first transfer pattern, and a first transfer pattern forming process,
The first transfer pattern has a shape for forming the first thin film pattern in the electronic device by exposure, and has a line width mark pattern that is not resolved by an exposure apparatus used in the exposure. Having a shape including
In the electronic device, in order to form the second thin film pattern, a part of the first transfer pattern defined by the mark pattern can be removed by an additional process in the electronic device. A method for producing a photomask, comprising:   The photomask blank according to claim 9 or 10, wherein the photomask blank is formed by laminating the semi-transparent film and the light-shielding film having different etching characteristics on the transparent substrate in this order. Mask manufacturing method. A photomask for manufacturing an electronic device having a laminated structure in which a first thin film pattern obtained by patterning a first thin film and a second thin film pattern obtained by patterning a second thin film are laminated on the same substrate. There,
A first transfer pattern for forming the first thin film pattern, in which the formed semi-transparent film and light shielding film are respectively patterned on a transparent substrate,
The first transfer pattern has a shape for forming the first thin film pattern of the electronic device by exposure, and a mark pattern having a line width that is not resolved by an exposure apparatus used for the exposure. Has a shape to include,
In order to obtain a second transfer pattern for forming the second thin film pattern of the electronic device, a part of the first transfer pattern defined by the mark pattern may be removed by an additional process. A photomask characterized in that it is possible.   The second transfer pattern includes a translucent portion surrounded by a semi-transparent portion, a translucent portion surrounded by a light-shielding portion, a semi-transparent portion surrounded by the light-shielding portion, and a light-shielding surrounded by the semi-transparent portion. The photomask according to claim 12, wherein the photomask includes any one of: a light-shielding portion surrounded by a light-transmitting portion, and a semi-light-transmitting portion surrounded by the light-transmitting portion.   The mark pattern is formed of a semi-light-transmitting part or a light-transmitting part having a width of 0.3 to 1.5 μm surrounding a part of the light-shielding part of the first transfer pattern. The photomask described in 1.   The manufacturing method of a display apparatus using the manufacturing method of the electronic device of any one of Claims 1-8.

Images