JP2005039082A - Mask blank, stencil mask, method for manufacturing the same, and method for exposing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive mask blank to be worked into a stencil mask for an exposing device using electrically charged particle lines for use with the surface flatness suitable for acquiring a stencil mask for an electronic ray which is simple in film thinning and stress adjustment, which is high in mechanical strength, and which is excellent in electronic ray irradiation tolerance, and matching the mask working process; and to provide a method for manufacturing the stencil mask and its exposing method as well as the mask blank and the stencil mask. <P>SOLUTION: This mask blank to be worked into a stencil mask for an exposing device using electrically charged particle lines for use is provided with a substrate and a mask base body supported by the substrate. The materials of the mask base body is constituted of a diamond thin film constituted of multi-crystal whose surface is provided with projection/recession and a flat layer on the diamond thin film. Thus, it is possible to provide the mask blank, the stencil mask using it and its manufacturing method and its exposing method. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exposure apparatus used, for example, in the manufacture of semiconductor devices and the like, and is used by processing into a transfer mask for an exposure apparatus using a charged particle beam such as an electron beam or an ion beam. The present invention relates to a blank and a stencil mask, a manufacturing method thereof, and an exposure method thereof.

  In recent years, miniaturization of semiconductor elements has been progressing rapidly. Various exposure techniques have been developed as manufacturing techniques for elements having such fine patterns. For example, there are exposure methods using electron beams such as partial exposure of electron beams and electron stepper exposure, exposure methods using ions, exposure methods using light in the vacuum ultraviolet region, exposure methods using light in the extreme ultraviolet region, etc. .

  Among these, as an exposure method using an electron beam, Patent Document 1 discloses a method of performing an equal magnification exposure using an electron beam. This method (LEEPL (Low energy electron-beam proximity projection lithography)) has an electron beam acceleration voltage that is 1/20 of that of an exposure method using an electron beam such as an electron beam division reduction transfer method. It is a kilovolt, that is, it has a feature of using a low energy electron beam.

  For example, in LEEPL, a stencil mask for forming a transmission port is used for pattern formation. A small gap of about 40 μm is maintained between the stencil mask and the wafer to be transferred, and the electron beam is exposed by proximity transfer that does not have the influence of the Coulomb effect. In the stencil mask used for the same magnification exposure, the processing accuracy of the mask pattern is important. In particular, the aspect ratio, which is the ratio between the mask film thickness and the mask pattern line width (electron beam transmission hole diameter), is a problem. The mask pattern is processed by dry etching, but the aspect ratio is usually about 10. Therefore, for example, in order to form a pattern with a line width of 100 nm, the thickness of the mask is limited to about 1 μm.

  Therefore, Patent Document 1 described above discloses that a stencil mask made of single crystal silicon has a thickness of 0.2 μm to 1.0 μm. However, this patent publication does not describe any method for manufacturing such a stencil mask made of single crystal silicon.

  Usually, when single crystal silicon is used as the material of the thin film constituting the stencil mask, a substrate is required to support the thin film and maintain the flatness of the mask. As this substrate, single crystal silicon is used from the viewpoint of processability and availability. As the mask blank, an SOI (Silicon On Insulator) substrate having a structure in which a silicon oxide film is sandwiched between two single crystal silicon substrates is used for performing fine processing of a thin film by etching. The mask pattern is produced by polishing one monocrystalline silicon substrate to a predetermined thickness and then patterning. At this time, the silicon oxide film that is an intermediate layer of the SOI substrate functions as an etching stopper when the mask pattern is processed.

However, with such a method, it is extremely difficult to polish the single crystal silicon substrate to the above-described thin film of 0.2 μm to 1.0 μm. In addition, with such a film thickness, there is a problem that in the stencil mask manufacturing process, the thin single crystal silicon substrate is cracked by the stress of the silicon oxide film.

  For this reason, a stress adjustment process is required for the single crystal silicon thin film formed on the silicon oxide film, but in such a case, a manufacturing process such as ion doping increases, which causes a problem that the tact time becomes long. .

  Further, when silicon is used as the mask material as described above, the material has a small hardness and Young's modulus, and thus there is a limit to the miniaturization and shape of the pattern.

When exposure is performed with a low energy electron beam having an acceleration voltage of about several kilovolts, electrons incident on the stencil mask are not transmitted but scattered or absorbed. Therefore, the mask material requires high electron beam irradiation resistance, particularly high thermal conductivity. However, silicon conventionally used as a mask material has a small thermal conductivity, and thus limits the miniaturization and shape of the pattern.
Japanese Patent No. 2951947

  The present invention is made under such circumstances, and is suitable for obtaining a stencil mask for an electron beam that is easy to thin and stress-adjust, has high mechanical strength, and is excellent in electron beam irradiation resistance. An object of the present invention is to provide a mask blank and a stencil mask having a surface flatness suitable for a mask processing process, a manufacturing method thereof, and an exposure method thereof.

  In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention is a mask blank used by processing into a stencil mask for an exposure apparatus using a charged particle beam. A mask blank comprising a thin film and a mask base composed of a flattened layer having a flat surface on the diamond thin film.

  According to the present invention as described above, since the material for the stencil mask is constituted by the diamond thin film having high hardness, Young's modulus and high thermal conductivity as the mask blanks, as a result, the mechanical strength is high and A stencil mask having high electron beam irradiation resistance can be obtained.

  Furthermore, since the planarization layer is formed on the diamond thin film, the unevenness caused by the polycrystalline crystal grains on the surface of the diamond thin film generated during film formation is compensated, and the surface of the mask blank is flattened. be able to. By flattening the surface in this way, it is possible to improve resist coating properties, etching accuracy, and reproducibility during patterning, and it becomes possible to manufacture a stencil mask with higher definition and higher accuracy. Further, the polishing process for the surface of the polycrystalline diamond thin film, which has been essential in the past, is no longer necessary, and the cost for manufacturing mask blanks and stencil masks can be greatly reduced.

  In addition, this planarization layer can be used as an etching mask when etching the diamond thin film at the same time when producing a stencil mask. Since the diamond thin film is made of carbon, it is processed by reactive etching using a gas mainly composed of oxygen. Usually, a two-layer resist is required to improve the etching selectivity. However, according to the present invention, since the planarizing layer can be used as an etching mask, an ordinary electron beam resist made of an organic substance can be used as a single layer during mask patterning.

  Furthermore, the invention according to claim 2 of the present invention is the mask blank according to claim 1, wherein the planarization layer has a thickness of 0.1 μm or more and 1 μm or less.

  A diamond thin film formed on a heterogeneous substrate such as a silicon substrate is not a single crystal but a polycrystal. Their particle size varies depending on the nucleation density (which can be controlled by the production conditions), but is usually several nm or more, many are 0.05 μm or more, and the surface irregularities are the same. As a result of the examination, it was found that the surface of the diamond thin film having such irregularities can be flattened by providing a flattening layer of 0.1 μm or more.

  In the invention according to claim 3 of the present invention, the planarization layer is made of any one or more of metal, silicon, oxides, nitrides and carbides thereof. The mask blanks according to 1 or 2.

  By using metal and silicon, which can be formed by sputtering or chemical vapor deposition, and has high oxygen plasma resistance, the mask surface can be flattened and the etching mask layer can be used for mask fabrication. Available for both. In addition, stress adjustment is indispensable for this flattening layer as well as the diamond thin film, but by using compounds such as metal, silicon oxide film, nitride film, carbide film, stress adjustment by composition control is possible, Higher stress controllability can be obtained.

  The invention according to claim 4 of the present invention is the mask blank according to any one of claims 1 to 3, wherein the diamond thin film has a thickness of 0.05 μm or more and 2 μm or less.

  Film thicknesses in this range were difficult to produce by single-crystal silicon deposition or polishing, but diamond thin films can be easily obtained with good controllability on the substrate by chemical vapor deposition. .

  Here, the invention according to claim 5 of the present invention is characterized in that the diamond thin film is doped with at least one selected from the group consisting of boron, sulfur, nitrogen or phosphorus as an impurity. Item 5. The mask blank according to any one of Items 1 to 4.

  By such impurity doping, the diamond thin film exhibits impurity conductivity and can be imparted with conductivity. That is, when processed and applied as a stencil mask, charge-up due to electron beam irradiation can be avoided.

  The invention according to claim 6 of the present invention is the mask blank according to any one of claims 1 to 5, wherein an etching stopper layer is interposed between the substrate and the diamond thin film. is there.

  When making a stencil mask, the substrate is etched into a predetermined shape from the back side, and the etching stopper layer is interposed in the process of penetrating to the diamond thin film that becomes the mask material, so that it is possible to perform etching with higher controllability and no residue. Become.

  The invention according to claim 7 of the present invention is the mask blank according to any one of claims 1 to 6, wherein the mask base has a transmission hole pattern through which a charged particle beam passes, and the surface is uneven. A stencil mask characterized by comprising a polycrystalline diamond thin film layer having a surface and a planarized layer having a flat surface on the diamond thin film layer.

  Here, in the case of a LEEPL stencil mask that uses a low-energy electron beam for exposure, a wafer to be exposed is placed on the planarization layer side due to physical restrictions in order to perform proximity exposure transfer. That is, since the exposure electron beam is incident from the diamond thin film layer side having high thermal conductivity, high electron beam irradiation resistance can be obtained without depending on the planarizing layer material.

  In this way, by flattening the surface, it is possible to avoid contact between the stencil mask and the wafer during handling of transfer by proximity exposure, and to avoid damage to the wafer even in the event of contact.

  Furthermore, the invention according to claim 8 of the present invention includes a step of forming a diamond thin film on a substrate by a chemical vapor deposition method using a source gas containing hydrocarbon, and a sputtering method on the diamond thin film. A mask blank according to any one of claims 1 to 6, further comprising a step of forming a planarizing layer by any one of chemical vapor deposition and ion plating. It is a manufacturing method.

  According to such an invention, it is possible to control the crystallinity and crystal grain size by controlling the chemical reaction by forming a diamond thin film as a mask material by chemical vapor deposition. The thickness and stress can be easily adjusted. Further, even when the planarizing layer is formed on the uneven surface by using a film forming method in which the energy of incident particles is large when forming the film, such as sputtering or chemical vapor deposition, the surface is flat. A membrane can be obtained.

  The invention according to claim 9 of the present invention includes a step of forming a diamond thin film on a substrate by a chemical vapor deposition method using a source gas containing hydrocarbon, a sputtering method, a chemical process on the diamond thin film. The method includes: a step of forming a planarization layer by any one of a vapor deposition method and an ion plating method; and a step of sequentially patterning the planarization layer and the diamond thin film. 7. A method for producing a stencil mask according to claim 7.

  As described above, according to the present invention, it is suitable for obtaining a stencil mask for an electron beam that is easy to be thinned and stress-adjusted and has high mechanical strength and excellent electron beam irradiation resistance, and It is possible to obtain a stencil mask having a surface flatness suitable for the mask processing process and a low cost.

  Furthermore, the resist coating property, etching accuracy, and reproducibility can be improved during patterning, and a stencil mask with higher definition and higher accuracy can be manufactured. Further, the polishing process for the surface of the polycrystalline diamond thin film, which has been essential in the past, is no longer necessary, and the production cost of the stencil mask can be greatly reduced.

  The invention according to claim 10 of the present invention is a charged particle beam exposure method comprising a step of irradiating the stencil mask according to claim 7 with a charged particle beam and shaping the charged particle beam into a transfer pattern shape.

  According to such an exposure method, it is possible to perform pattern exposure with high accuracy on a resist formed on a substrate for a semiconductor device, and as a result, a pattern for a semiconductor device can be manufactured with a high yield.

In the mask blank of the present invention, since the mask base material is composed of a diamond thin film, the thin film can be formed with high controllability by chemical vapor deposition, and the stress can be adjusted by controlling the film thickness and particle size. It can be done easily. In addition, since a flattening layer is provided on the mask base, polishing is not required and the cost can be reduced. In addition, a flat shape suitable for the mask processing process can be obtained, and it can also be used as an etching mask for a diamond thin film. Can do. In addition, according to the manufacturing method of the present invention, it is possible to easily obtain a mask blank having excellent charged particle beam irradiation characteristics with high accuracy without causing cracks and peeling due to stress.

  Therefore, the stencil mask manufactured using the mask blanks according to the present invention is excellent in charged particle beam irradiation characteristics, and can be easily obtained with high accuracy without causing cracks and peeling due to stress. Moreover, according to the manufacturing method of the present invention, it is possible to easily obtain a stencil mask having excellent charged particle beam irradiation characteristics with high accuracy without causing cracks and peeling due to stress.

  According to the exposure method of the present invention, it is possible to perform pattern exposure with high accuracy on a resist formed on a substrate for a semiconductor device, and as a result, a pattern for a semiconductor device can be manufactured with a high yield.

  Embodiments according to one embodiment of the present invention are described below with reference to the drawings.

  FIG. 1 is a side sectional view showing a mask blank according to one embodiment of the present invention.

  In FIG. 1, the mask blank is composed of a substrate 11, a diamond thin film 12 having a concavo-convex surface as a mask material on the substrate 11, and a planarizing layer 13 on the diamond thin film 12. .

  As the substrate, in addition to single crystal silicon, a quartz substrate or a ceramic substrate can be used.

  As the diamond thin film 12 serving as a mask material, a diamond thin film made of polycrystal or a diamond thin film made of nanocrystals having a smaller crystal grain size can be used.

  Here, the diamond thin film 12 may be doped with at least one of impurities such as boron, sulfur, nitrogen, and phosphorus.

  The film thickness of the diamond thin film 12 is desirably 0.05 μm or more and 2 μm or less. If the film thickness is too thin, the strength of the diamond thin film 12 may decrease when the current value is increased to increase the throughput, and if it is too thick, the mask pattern processing accuracy cannot be increased.

  The planarizing layer 13 desirably has a thickness of 0.1 μm or more and 1 μm or less. If the film thickness is thinner than this, sufficient surface flatness cannot be obtained.

  Further, the planarizing layer 13 is made of a thin film material that can be formed by a method having a high incident energy, such as sputtering, chemical vapor deposition, or ion plating, and that is highly resistant to etching by oxygen plasma. Can do.

Here, the material of the planarizing layer 13 is preferably one or more of metal, silicon, oxides, nitrides, and carbides thereof. The metal can be selected from refractory metals such as tungsten, molybdenum, tantalum and niobium, or chromium, titanium and their oxides, nitrides and carbides. Alternatively, it can be selected from silicon, silicon oxide, silicon nitride, and silicon carbide.

  FIG. 2 is a side sectional view showing another mask blank according to one embodiment of the present invention.

  In FIG. 2, the mask blank includes a substrate 21, an etching stopper layer 24 on the substrate 21, and a diamond thin film 22 made of polycrystal having an uneven surface as a mask material formed on the etching stopper layer 24. And a planarizing layer 23 on the diamond thin film 22.

  Here, the substrate 21, the diamond thin film 22, and the planarization layer 23 can each be composed of the same structure and materials as described above with reference to FIG. 1. The etching stopper layer 24 functions as a stopper layer when the substrate 21 is removed by etching when a stencil mask is manufactured. The material of the etching stopper layer 24 can be selected from materials that are resistant to the etchant used when the substrate 21 is etched.

  Here, when silicon is used as the substrate 21, generally reactive ion etching using an etching gas containing a fluorine compound as a main component is used for etching. In this case, silicon oxide can be used as the etching stopper layer 24.

  In the mask blank according to the present embodiment configured as described above, a thin diamond film is used as a mask material in place of a conventionally used single crystal silicon thin film, so that a thin film can be formed. In addition, the stress can be adjusted by controlling the particle size.

  In addition, since the diamond thin film used as a mask material exhibits material properties of high hardness and high thermal conductivity, when used as a mask, it has excellent electron beam irradiation resistance and forms a pattern with a desired aspect ratio with high accuracy. Is possible.

  Furthermore, since a flattening layer is provided on the diamond thin film, a step for polishing the diamond thin film is not required, and it also functions as an etching mask in the mask processing process. An organic electron beam resist can be used in a single layer without using a resist.

  Next, the manufacturing method of the mask blank of this invention demonstrated above is demonstrated with reference to Fig.3 (a), (b).

  FIG. 3 is a side cross-sectional view illustrating a manufacturing process of mask blanks according to one embodiment of the present invention.

  First, as shown in FIG. 3A, a diamond thin film 32 is formed on a substrate 31 by chemical vapor deposition. Here, as the chemical vapor deposition method, microwave plasma chemical vapor deposition or hot filament chemical vapor deposition can be used.

  Subsequently, as shown in FIG. 3B, a planarizing layer 33 is formed on the diamond thin film 32 by sputtering, chemical vapor deposition, or ion plating. Here, the planarizing layer 33 can be selected from metal, silicon, or oxides, nitrides, and carbides thereof. The compound can be formed by reactive film formation in which oxygen, nitrogen, or carbon is added with oxygen, nitrous oxide, nitrogen, ammonia, or a hydrocarbon gas.

  FIG. 4 is a side cross-sectional view illustrating a stencil mask according to an aspect of the present invention.

In FIG. 4, the stencil mask has a diamond thin film layer 42 made of polycrystal having a predetermined transmission hole pattern on the support base 41 in which the opening 45 is formed, and having irregularities on the surface, and the diamond thin film layer 42. The upper surface is composed of a flattened layer 43 having a flat surface. The mask base made of the diamond thin film layer 42 and the flattening layer 43 has a transmission port 46 formed therein.

  As the support base 41, a quartz substrate or a ceramic substrate can be used in addition to single crystal silicon.

  As the diamond thin film layer 42 constituting the mask matrix, a polycrystalline diamond thin film or a diamond thin film made of nanocrystals having a smaller crystal grain size can be used.

  The film thickness of the diamond thin film layer 42 is desirably 0.15 μm or more and 2 μm or less.

  The diamond thin film layer 42 may be doped with at least one selected from the group consisting of impurities such as boron, sulfur, nitrogen and phosphorus.

  It is desirable that the planarization layer 43 constituting the mask base has a thickness of 0.1 μm or more and 1 μm or less. If the film thickness is thinner than this, sufficient surface flatness cannot be obtained.

  The planarizing layer 43 is made of a thin film material that can be formed by a method with high incident energy, such as sputtering, chemical vapor deposition, or ion plating, and has high resistance to etching by oxygen plasma. Can do.

  Here, the material of the planarizing layer 43 is preferably one or more of metal, silicon, oxides, nitrides, and carbides thereof. The metal can be selected from refractory metals such as tungsten, molybdenum, tantalum and niobium, or chromium, titanium and their oxides, nitrides and carbides. Alternatively, it can be selected from silicon, silicon oxide, silicon nitride, and silicon carbide.

  FIG. 5 is a side cross-sectional view illustrating another stencil mask according to an aspect of the present invention.

  In FIG. 5, a stencil mask is formed on a support base 51 having an opening 55 formed thereon, an etching stopper layer 54 on the support base 51 of single crystal silicon, and a stencil mask material formed on the etching stopper layer 54. The diamond thin film layer 52 is made of a polycrystal having a concavo-convex surface and a planarizing layer 53 on the diamond thin film layer 52. A mask base made of the diamond thin film layer 52 and the flattening layer 53 has a transmission port 56 formed therein.

  Here, each of the support base 51, the diamond thin film layer 52, and the planarization layer 53 can be made of the same structure and material as described above with reference to FIG. The etching stopper layer 54 functions as a stopper layer when the support base 51 is removed by etching when a stencil mask is produced. The material of the etching stopper layer 54 can be selected from materials that are resistant to the etchant used when the support base 51 is etched.

  Here, when silicon is used as the support substrate 51, generally, reactive ion etching using an etching gas containing a fluorine compound as a main component is used for etching. In this case, silicon oxide can be used as the etching stopper layer 54.

  In the stencil mask according to the present embodiment configured as described above, a thin diamond film is used as a mask material instead of the conventionally used single crystal silicon thin film. In addition, the stress can be adjusted by controlling the particle size.

  In addition, the diamond thin film used as a stencil mask material exhibits material properties with high hardness and high thermal conductivity. Therefore, when used as a stencil mask, it has excellent electron beam irradiation resistance and forms a pattern with a desired aspect ratio with high accuracy. Is possible.

  Further, since the flattening layer 53 is provided on the diamond thin film, a step of polishing the diamond thin film is unnecessary, and the mask processing process also functions as an etching mask. An organic electron beam resist can be used as a single layer without using a layer resist.

  Next, the manufacturing process of the stencil mask of the present invention described above will be described with reference to FIGS.

  FIG. 6 is a cross-sectional side view illustrating a manufacturing process of a stencil mask according to one embodiment of the present invention.

  First, as shown in FIG. 6A, a diamond thin film 62 is formed on a substrate 61 by chemical vapor deposition. Here, as the chemical vapor deposition method, microwave plasma chemical vapor deposition or hot filament chemical vapor deposition can be used.

  Subsequently, as shown in FIG. 6B, a planarizing layer 63 is formed on the diamond thin film 62 by sputtering, chemical vapor deposition, or ion plating. Here, the material of the planarizing layer 63 can be selected from metal, silicon, or oxides, nitrides, and carbides thereof. The compound can be formed by reactive film formation in which oxygen, nitrogen, or carbon is added with oxygen, nitrous oxide, nitrogen, ammonia, or a hydrocarbon gas.

  Next, as shown in FIG. 6C, the support base 61 is formed by providing an opening 65 in the support base 61. In this step, dry etching, wet etching, ultrasonic processing, sandblasting, or the like can be suitably used.

  Thereafter, as shown in FIG. 6D, the planarization layer 63 and the diamond thin film 62 are patterned to form a mask base 67 having a predetermined transmission hole pattern 66. In the process of forming the transmission hole pattern, a step of forming a resist pattern on the planarization layer 63 is performed. Using the resist pattern as an etching mask, the planarization 63 is dry-etched to form the planarization layer 63 having a transmission port 66. And subsequently, after removing the resist pattern, using the planarizing layer 63 having the transmission port as an etching mask, the diamond thin film 62 is dry etched to form the diamond thin film layer 62 having the transmission port 66. It goes through in order. This completes the stencil mask.

  Here, examples of the dry etching apparatus include apparatuses using discharge methods such as RIE, magnetron RIE, ECR, ICP, microwave, helicon wave, and NLD. Note that any of the forming process of the support base 61 and the patterning process of the planarizing layer 63 and the diamond thin film 62 may be performed first.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
<Example 1>
With reference to FIGS. 3A and 3B, a mask blank manufacturing method according to an embodiment of the present invention will be described.

  As shown in FIG. 3A, a diamond thin film 32 was formed on a single crystal silicon substrate 31 having a thickness of 525 μm using a microwave plasma chemical vapor deposition apparatus. The microwave plasma chemical vapor deposition conditions are as shown in Table 1 below.

Subsequently, as shown in FIG. 3B, a chromium nitride thin film was formed as the planarizing layer 33 on the diamond thin film 32 by using a reactive sputtering method. The conditions for reactive sputtering are as shown in Table 2 below.

In the mask blanks manufactured as described above, the diamond thin film 32 serving as a mask material has a very thin film thickness of 500 nm and has low stress, so that peeling or cracking does not occur and conductivity is exhibited. Further, since the planarizing layer 33 is provided, the mask blank surface is flat and used as an etching mask, and is suitable for the mask processing process. Furthermore, the stencil mask produced using this mask blank has high pattern accuracy and excellent charged particle beam irradiation characteristics.

A manufacturing process of a stencil mask according to one embodiment of the present invention will be described with reference to FIGS.
<Example 2>
As shown in FIG. 6A, a diamond thin film 62 was formed on a single crystal silicon substrate 61 having a thickness of 525 μm using a microwave plasma chemical vapor deposition apparatus. The conditions of microwave plasma chemical vapor deposition are as shown in Table 3 below.

Subsequently, as shown in FIG. 6B, a chromium nitride thin film was formed as the planarizing layer 63 on the diamond thin film 62 by using a reactive sputtering method. The conditions for reactive sputtering are as shown in Table 4 below.

Next, a protective film (not shown) made of a silicon nitride film is formed on the entire surface by using a plasma CVD (Chemical Vapor Deposition) apparatus, and then on the opening 65 formation region of the single crystal silicon substrate 61 by dry etching. The protective film was removed.

  Next, as shown in FIG. 6 (c), the single crystal silicon substrate 61 is anisotropy along the plane orientation by storing it in an etching solution of an aqueous KOH solution heated to about 90 ° C. and using the protective film as a mask. Etching was performed to form an opening 65. Next, the protective film was removed by etching with hot phosphoric acid at about 170 ° C.

  Subsequently, an electron beam resist (not shown) is applied to a thickness of 0.5 μm on the planarizing layer 63 made of a chromium nitride thin film, and this is drawn using an electron beam drawing machine with an acceleration voltage of 20 kV, Thereafter, development was performed using a dedicated alkaline developer to form a resist pattern.

Next, using the resist pattern as a mask, using a plasma etching apparatus and using chlorine and oxygen as etching gases, the planarizing layer 63 made of a chromium nitride thin film is dry-etched to a depth reaching the diamond thin film 62 and transmitted. After the planarization layer 63 having a mouth was formed, the resist pattern was removed by ashing with oxygen plasma.

  Subsequently, the diamond thin film 62 was etched by ICP using the planarizing layer 63 made of chromium nitride as an etching mask and oxygen was used as an etching gas to form a diamond thin film layer 62 having a transmission port, thereby completing a stencil mask.

  In the stencil mask manufactured as described above, the thickness of the mask base 67 is as very thin as 500 nm and the stress is low, so that peeling and cracking do not occur and the resistance is low, so a separate metal film is provided. There is no need. Further, the obtained stencil mask has high pattern accuracy and excellent charged particle beam irradiation characteristics.

The side sectional view showing the mask blanks concerning one mode of the present invention. The side sectional view showing other examples of the mask blanks concerning one mode of the present invention. The sectional side view which shows the manufacturing process of the mask blank which concerns on 1 aspect of this invention. 1 is a side cross-sectional view illustrating a stencil mask according to one embodiment of the present invention. FIG. 6 is a side cross-sectional view illustrating another example of a stencil mask according to one embodiment of the present invention. The sectional side view which shows the manufacturing process of the stencil mask which concerns on 1 aspect of this invention.

Explanation of symbols

11, 21, 31 ... substrates 41, 51, 61 ... support bases 12, 22, 3242, 52, 62 ... diamond thin films 13, 23, 3343, 53, 63 ... planarization layers 24, 54 ... etching stopper layers 45, 55 , 65... Openings 46, 56, 66...
67 ... Mask body

Claims (10)

  In a mask blank used by processing into a stencil mask for an exposure apparatus using a charged particle beam, the substrate comprises a polycrystalline diamond thin film and a flattened layer having a flat surface on the diamond thin film. A mask blank characterized in that a mask base is supported.   The mask blank according to claim 1, wherein the planarizing layer has a thickness of 0.1 μm or more and 1 μm or less.   3. The mask blank according to claim 1, wherein the planarization layer is made of one or more of metal, silicon, oxides thereof, nitrides, and carbides thereof.   4. The mask blank according to claim 1, wherein the diamond thin film has a thickness of 0.05 μm or more and 2 μm or less. 5.   5. The mask blank according to claim 1, wherein the diamond thin film is doped with at least one selected from the group consisting of boron, sulfur, nitrogen, and phosphorus as impurities. .   The mask blank according to any one of claims 1 to 5, wherein an etching stopper layer is interposed between the substrate and the diamond thin film.   The mask blank according to any one of claims 1 to 6, wherein the mask base has a transmission hole pattern through which a charged particle beam passes, and a diamond thin film layer made of polycrystal having irregularities on the surface; A stencil mask comprising a planarized layer having a flat surface on the diamond thin film layer.   A process for forming a diamond thin film on a substrate by a chemical vapor deposition method using a source gas containing hydrocarbon, and a sputtering method, a chemical vapor deposition method, an ion plating method on the diamond thin film. The method for producing a mask blank according to claim 1, further comprising a step of forming a planarizing layer by any one of the methods.   A process of depositing a diamond thin film on a substrate by a chemical vapor deposition method using a source gas containing hydrocarbon, and any of a sputtering method, a chemical vapor deposition method and an ion plating method on the diamond thin film. 8. The method for manufacturing a stencil mask according to claim 7, further comprising: a step of forming a planarizing layer by the method, and a step of sequentially patterning the planarizing layer and the diamond thin film.   A charged particle beam exposure method comprising a step of irradiating the stencil mask according to claim 7 with a charged particle beam and forming the charged particle beam into a shape of a transfer pattern.