JPS5870534A - Method of forming lift-off shadow mask - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a technology for manufacturing devices using optical manufacturing technology, and more specifically, the present invention relates to a technology for manufacturing devices using optical manufacturing technology, and more specifically, for forming masks used in such manufacturing technology. (
In the technical field of 2007, it is practiced to form a layer or a layer made of a predetermined material in a predetermined shape on a selected surface.

For example, after forming an integrated circuit on the surface of a semiconductor chip, it is necessary to make electrical contacts to numerous elements or regions of the circuit. Such contacts can be obtained by forming a contact material into a predetermined shape on the surface of the integrated circuit.

In this case, the contact material is separated from the surface by an insulating layer.

As another example, it may be desirable to form a predetermined shape in the form of a narrow notch in a layer of a passivating material, such as silicon oxide, in conjunction with the formation of a device on or in the substrate. There may be cases where Yet another example is to form a separate mask rather than a mask on the surface of the actual device and use it to expose and process the actual device. In each of these various applications, formation of a particular material or layer into a predetermined shape may be performed.

It is known to form films of a certain material into a certain shape by etching, lifting, or a combination of these techniques. In the lift method, a film material is partially deposited on a surface and partially deposited on a lifting material patterned on the surface. The lifting material is then removed along with the film material deposited thereon to form a desired pattern of film material on the surface.

Depositing the membrane material onto the lifting material and exposed portions of the surface.
When it is allowed to do so, the membrane material assumes a continuous shape. Therefore, when such lifting material is removed, the layer of membrane material must be destroyed. Destroying the film material in this manner not only causes problems in the precision of pattern formation, but also in its functional characteristics.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a method for forming a lift-off shadow mask that can form a film material into a predetermined shape with high precision.

A second feature of the present invention is to provide a method for forming a membrane material into a predetermined shape, the method comprising: forming a first material layer on a surface; forming a second material layer on the etchant, wherein when the first material and the second material are exposed to a common etchant, the first material has a greater etching rate than the second material; etching a portion of the second material and a portion of the first material below the second material using a common etchant to expose a portion of the surface; and the exposed portion of the surface and the second material layer. forming a film material layer over the remaining portion of the first material layer; and removing the remaining portion of the first material layer and removing the remaining portion of the first material layer.
This method is characterized by having each of the above-mentioned steps of removing both the substance and the film material.

Hereinafter, specific implementation of the present invention will be explained with reference to the attached drawings.
will be explained in detail. 11ji! ! l designates a substrate 1.0 of semiconductor material. A layer 12 of thermal oxide having an upper surface 13 is formed over the substrate 10 .

According to the method of the invention, a layer 14 of germanium dioxide is formed on surface 13, and then a layer 16 of silicon dioxide is formed on layer 14.

The germanium dioxide layer 14 and the silicon dioxide layer 16 are formed by CvD technology.

Germanium dioxide layer 14 is deposited in a conventional CvD reactor maintained at approximately 400°C. Approximately 4 nitrogen scum
A flow rate of 0 liters/min is introduced into the reaction vessel. Also, oxygen is introduced into the reaction vessel at a flow rate of about 1.5 liters/minute. Also, germane was introduced into the reaction vessel at a flow rate of about 15 CC/min, so the ratio of oxygen to germane was about 100:
It is 1. Therefore, the germanium dioxide layer 14 is
3 at a rate of about 20 OA/min to a thickness of about 750 OA.

Once germanium dioxide layer 14 has been deposited, silicon dioxide layer 16 is deposited by maintaining the reaction vessel at about 400 DEG C. and introducing nitrogen gas at a flow rate of about 40 liters per minute. 11I is introduced into the reaction vessel at a flow rate of approximately 1.5 liters/minute. Also, add silane to about 150C.
The oxygen to silane ratio is approximately 100:1. Accordingly, a silicon dioxide layer 16 is deposited over the germanium dioxide layer 14 to a thickness of about 250 OA at a rate of about 100 OA/min.

Using conventional photolithographic techniques, a patterned layer of photoresist is formed, as shown in FIG. As the photoresist material in this case, for example, a photoresist such as AZ can be used. The photoresist is formed in a continuous layer using standard photoresist coating equipment. The photoresist is then exposed and developed using known photoetching techniques, resulting in an image 1 of photoresist material as shown in FIG.
8 remains.

The exposed areas of the silicon dioxide layer 16 and underlying germanium dioxide layer 14 are then removed as shown in FIG. It exhibits an etch rate 5 to 10 times faster than undoped silicon dioxide.

Therefore, by masking the layer structure shown in Figure 2 with photoresist and then etching in a reaction vessel using a CFa-based plasma, an undercut shadow mask structure as shown in Figure 4 can be created. It is possible to form. In a preferred embodiment of the invention, silicon dioxide and germanium dioxide are combined with 4% CF410.
2 plasma at about 0.4 Torr and about 300 to 4
IPC barrel (Barrel) under the condition of 00 watts.
) Etching is performed in an etching device.

Next, the photoresist 18 is removed, but in this case,
Preferably, it is removed by "ashing" in an O2 plasma to expose the underlying silicon dioxide layer 16, as shown in FIG.

A film material 20 to be patterned is then deposited on the exposed surface of silicon dioxide polish 16 and on the exposed portions of surface 13 of thermal oxide layer 12 . 6th
As shown in the figure, in a preferred embodiment, the membrane material 2o
After depositing the silicon dioxide layer 16, a gap or pocket exists below the undercut portion of the silicon dioxide layer 16. The entire construction is then immersed in water. Germanium dioxide formed in the manner described above is completely water-soluble; -Germanium dioxide is water-insoluble;
The germanium dioxide layer is dissolved to remove the silicon dioxide carried thereon, thus leaving a patterned film material 20, as shown in FIG.

The method of the present invention described above has various unique effects. First, the rift-on off film, ie, the combined silicon dioxide and germanium dioxide film, can be deposited in large quantities using low pressure CVD techniques. Second, the materials used are "clean insulators", even at high lr! Even if used in 1, no contamination problem will occur. It is possible to use water as a lifting solvent in jI3, which makes the invention highly advantageous. Fourth, because germanium dioxide and silicon dioxide are compatible oxides, it is possible to form mixtures thereof to vary the degree of etch rate and degree of texture.

The specific configuration of the present invention has been explained in detail above, but
The present invention should not be limited to these specific examples,
Of course, various modifications can be made without departing from the technical scope of the present invention.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a semiconductor substrate with a thermal oxide layer formed on top, and Fig. 2 shows a state in which a germanium dioxide layer is formed on the thermal oxide layer and a silicon dioxide layer is formed on the germanium dioxide layer. 3 is a cross-sectional view showing a state in which the photoresist is patterned in the configuration shown in FIG. 2, and FIG. 5 is a cross-sectional view showing the state after etching the silicon layer and germanium dioxide (2), FIG. 5 is a cross-sectional view showing the state after removing the photoresist in the structure of FIG. A cross-sectional view showing the state after a film material is deposited and formed in the configuration of
FIG. 7 is a sectional view showing the structure of FIG. 6 after silicon dioxide and germanium dioxide are removed. (Explanation of symbols) 10: Semiconductor substrate 12: Thermal oxide layer 14: Germanium dioxide layer 16 2 Silicon dioxide layer 18: Photoresist 20: II Materials License Applicant Fairchilde Camera and Instrument Corporation Procedural Amendment 1981 November 4th Commissioner of the Japan Patent Office Kazuo Wakasugi 1. Indication of the case 1980-5-7 Patent original
No. 166788 No. 2, Title of the invention Lift-off shadow mask forming method 3, Person making the amendment Relationship with the case Patent applicant 4, Agent 5, Date of amendment order Initiator

Claims (1)

[Claims] 1. A method for forming a film material into a predetermined shape, comprising: (a) forming a first material layer on a surface; (b) forming a second material layer on the first material layer; and when the J11 material and the second material are exposed to a common etchant, the first material has a higher etching rate than the first and second second materials, and (C) a common etchant. etching a portion of the second material and an underlying portion of the first material using an etchant to expose a portion of the surface; (d) on the exposed portion of the surface; forming a discipline material layer on the remaining portion of the second material layer; (e) removing the remaining portion of the first material and removing both the second material and the film material present thereon; A method characterized by comprising each step. 2. The method according to item 1 above, wherein the first substance is germanium dioxide. 3. The method according to item 1 or 2 above, wherein the second substance is silicon dioxide. 4. The method according to item 2 or 3 above, characterized in that the etching is performed by plasma etching. 5. In the above item 4, the common etchant is C.
A method characterized by F4-based plasma. 6. In item 1 above, the first layer is a water-soluble substance, the second layer is a water-insoluble substance, and the etching step includes coating the layer of the water-insoluble substance with a photoresist; patterning the photoresist to expose a portion of the water-insoluble material, and using a common etchant to pattern the exposed portion of the layer of water-soluble material and the portion of the water-soluble material underlying the layer; plasma etching to expose a portion of the surface, and the removing step includes immersing the remaining portion of the water-soluble material layer in water to dissolve the remaining portion of the water-soluble material layer. A method comprising the step of: removing the residual portion of the water-insoluble substance and the membrane material present thereon. 7. The method according to item 18 above, wherein the water-soluble substance is germanium dioxide. 8. The method according to item 6 or 7 above, wherein the water-insoluble substance is silicon dioxide. 9. In any one of the above items 6 to 8,
A method characterized in that the plasma is a CF4-based plasma.