JPH02230715A - Manufacture of x-ray mask - Google Patents

Abstract

PURPOSE:To obtain an X-ray mask having excellent accuracy in size by sticking a silicon substrate to a quartz substrate, forming a specified pattern on the silicon substrate by etching, embedding heavy metal films having a low X-ray transmitting coefficient into said pattern, and forming a quartz frame. CONSTITUTION:A silicon substrate 12 is stuck on a quartz substrate 11. The silicon substrate 12 is polished by combining a mechanical grinding and a chemical etching method. Thus a thin film of about 1-10mum is made to remain. Then, with a resist film 13 as a mask, anisotropic etching is performed, and grooves for forming an exposing pattern are formed in the silicon substrate 12. Then, heavy metal films 14 of gold, tungsten and the like whose X-ray transmittance is low are embedded in the grooves of the silicon substrate 12. Then, a mask 15 comprising silicon nitride is used, and the quartz substrate 11 other than its peripheral part which is to become a frame undergoes wet etching, and a quartz frame 16 is formed on the rear side of the quartz substrate.

Description

[Detailed Description of the Invention] [Summary] Regarding a method for manufacturing an X-ray mask used for X-ray exposure, we have developed an X-ray mask that can form an X-ray mask with good dimensional accuracy using conventional Noricon semiconductor technology. The purpose of the present invention is to provide a manufacturing method, which includes a step of bonding a silicon substrate to a quartz substrate, a step of etching the silicon substrate into a predetermined pattern, and a step of embedding a heavy metal film with a low X-ray transmission coefficient in the etched silicon substrate. and a step of removing a portion other than the periphery of the quartz substrate to form a quartz frame.

[Industrial application field]

The present invention relates to a method for manufacturing an X-ray mask used for X-ray exposure.

[Conventional technology]

2. Description of the Related Art In recent years, in semiconductor device manufacturing processes, as elements become smaller, conventional exposure methods using optical means are approaching their limits. For this reason, an X-ray exposure method is being considered in which a mask pattern is transferred to a resist on a wafer using X-rays. An example of the X-ray mask used for this X-ray exposure is the one disclosed in Japanese Patent Application Laid-Open No. 58-215023, and FIGS. 2(a) to 2(d) show such a conventional X-ray mask. FIG. 3 is a cross-sectional view showing the manufacturing process.

First, as shown in the figure (a), a quartz substrate 1 having a thickness of, for example, about 2 mm is prepared, and as shown in the figure (b), the surface of the quartz substrate 1 is coated with X-rays by chemical vapor deposition. A membrane film 2 made of silicon nitride or the like that transmits light is formed. Then, as shown in the figure (C), a heavy metal film 3 such as gold having an X-ray blocking ability is formed in a pattern on the Menplan film 2, and then, as shown in the figure (d), An X-ray mask is formed by etching the quartz substrate 1 from the back side to form a quartz frame 4.

[Problem to be solved by the invention]

In the production of conventional X-ray masks, advanced manufacturing technology is required to form the thin Memplan film 2 on the quartz substrate 1 and to form the heavy metal film pattern 3 on the Memplan film 2 with high precision. It is difficult to manufacture, and it is not possible to use conventionally established manufacturing techniques for silicon semiconductor integrated circuits suitable for microfabrication, so special processing techniques are required.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an X-ray mask manufacturing method that can form an X-ray mask with good dimensional accuracy using conventional silicon semiconductor integrated circuit manufacturing techniques.

[Failure to solve the problem]

The above-mentioned problems include a step of bonding a silicon substrate to a quartz substrate, a step of etching the silicon substrate into a predetermined pattern, a step of embedding a heavy metal film with a low X-ray transmission coefficient in the etched silicon substrate, and a step of embedding a heavy metal film with a low X-ray transmission coefficient on the quartz substrate. This is achieved by a method of manufacturing an X-ray mask, which is characterized in that it includes a step of removing a portion other than the peripheral portion of the mask and forming the mask into a quartz frame.

[Function] In the present invention, a silicon substrate is bonded to a quartz substrate, a predetermined pattern is etched on the silicon substrate,
Since a heavy metal film with a low X-ray transmission coefficient is embedded in this pattern and the quartz substrate is formed into a quartz frame, it becomes possible to use established microfabrication technology for manufacturing silicon semiconductor integrated circuits. Therefore, conventional semiconductor manufacturing equipment can be used, and an X-ray mask with high dimensional accuracy can be manufactured.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to an illustrated embodiment.

FIGS. 1(a) to 1(e) are cross-sectional views of the manufacturing process of an X-ray mask according to an embodiment of the present invention.

First, as shown in FIG. 5A, a silicon substrate 12 having a thickness of approximately 500 μm is bonded onto a quartz substrate 11 having a thickness of approximately 500 μm. This bonding can be done, for example, by applying heat treatment at a high temperature of about 1 (}00°C) while applying a high pressure of about several tons/cmz, or by using electrostatic force generated by pulses. A known method is used. In the method using high pressure and high temperature described above, the atoms on the contacting surfaces of the quartz substrate 11 and the silicon substrate 12 move and settle in mutually aligned positions due to pressure and heat. It is understood that it is pasted together by.

Next, as shown in FIG. 4B, the silicon substrate 12 is polished using a polishing technique that combines mechanical grinding and chemical etching, so that a thin film of about 1 to 10 μm remains.

Next, as shown in FIG. 2C, using the resist film 13 formed by electron beam exposure for pattern drawing as a mask, the silicon substrate 12 is coated with silicon tetrachloride (SiC), for example.
14) Perform anisotropic etching using gas. As a result, a groove for forming an exposure pattern is formed in the silicon substrate 12.

Next, as shown in the same figure (d), gold with low X-ray transmittance (
A heavy metal film 14 such as Au) or tungsten (1) is buried in the groove in which the pattern for exposure of the silicon substrate 12 is formed by a spatter method or the like, and then the silicon substrate 12 is
It is deposited thickly on the surface as shown by the two-dot chain line. after that,
The thickly deposited heavy metal film 14 is ground so that the surface of the silicon substrate 12 is exposed.

Next, as shown in FIG. 2(e), a mask 15 made of silicon nitride (SiN), for example,
Using the quartz substrate 11, except for the peripheral part that forms the frame,
The quartz frame 16 is removed by wet etching using a hydrofluoric acid (HF) solution or the like.

According to the above method for manufacturing an X-ray mask, a predetermined pattern is formed on the silicon substrate 11 bonded to the quartz substrate 11 by etching, a heavy metal film 14 with a low X-ray transmission coefficient is embedded in this pattern, and the quartz substrate 11 is It is formed in the frame 16, and such a manufacturing process can be carried out using established microfabrication technology in the manufacture of silicon semiconductor integrated circuits. Therefore, conventional silicon semiconductor manufacturing equipment can be used as is, and an X-ray mask with good dimensional accuracy can be manufactured using microfabrication technology.

Note that in the above embodiment, Au is used as the heavy metal film 14.
, W, etc., but any material with low X-ray transmittance, such as tantalum (Ta), may also be used.

(Effects of the Invention) As explained above, according to the present invention, a silicon substrate is bonded to a quartz substrate, a predetermined pattern is formed on the silicon substrate by etching, and a heavy metal film with a low X-ray transmission coefficient is embedded in this pattern. In order to form a quartz frame from a quartz substrate, it becomes possible to use established microfabrication technology for silicon semiconductor manufacturing. Therefore, it is possible to manufacture an X-ray mask with good dimensional accuracy using conventional semiconductor manufacturing equipment.

[Brief explanation of the drawing]

FIGS. 1(a) to (e) are cross-sectional views of the manufacturing process of an X-ray mask according to an embodiment of the present invention, and FIGS. 2(a) to (d) are cross-sectional views of the manufacturing process of a conventional X-ray mask. In the figure, 11 is a quartz substrate, 12 is a silicon substrate, 13 is a resist film, 14 is a heavy metal film, 15 is a mask, and 16 is a quartz frame. 4-1 is Ryou5-・Mask patent applicant Fujitsu Limited

Claims (1)

[Claims] A step of bonding a silicon substrate (12) to a quartz substrate (11), a step of etching the silicon substrate (12) into a predetermined pattern, and a step of exposing the etched silicon substrate (12) to X-rays. A process of embedding a heavy metal film (14) with a low permeability coefficient, and removing a portion other than the periphery of the quartz substrate (11) to form a quartz frame (16).
1. A method of manufacturing an X-ray mask, the method comprising: forming an X-ray mask.