JPH0613293A - Manufacture of x-ray mask - Google Patents

Abstract

PURPOSE:To obtain a method capable of simply and surely etching back an X-ray mask in a process. CONSTITUTION:An X-ray mask 100 in a process is stacked on a soft packing 12 of a flat plane type wherein a hole is formed in the central part, in the manner in which the pattern forming side faces downward. A soft packing 12 similar to the soft packing 12 is stacked on the mask 100. Part members 13, 14 having holes are stacked on the packing 12. A recessed part formed by the soft packing 12 on the X-ray mask 100 and the part members 13, 14 having holes is filled with etching liquid 20 of silicon, thereby perfoming etching- back.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an X-ray mask used in X-ray lithography.

[0002]

2. Description of the Related Art FIG. 3 shows an outline of an X-ray mask. The X-ray mask has a structure in which a circuit pattern 3 of an X-ray absorber made of a heavy element is formed on a thin film substrate 2 made of a light element and having a thickness of several μm (hereinafter referred to as a membrane). These are usually formed on a silicon wafer 1, and this silicon wafer 1 is bonded to a support frame 4 made of glass or ceramics.

As a method for manufacturing an X-ray mask, various methods have been proposed which differ in the materials used, the order of processes, the method of patterning the absorber, and the like.

FIG. 4 shows a document (monthly Semiconduc
tor World 1991.5, pp107-11.
It is a schematic diagram of an X-ray mask manufacturing process described in 1). In the figure, 1 is a silicon wafer, 2 is a membrane, 3a is an X-ray absorber, 3 is an X-ray absorber pattern, 4 is a support ring, 5 is a resist pattern, and 6 is a silicon dioxide film which serves as an etching mask for the absorber. Is. The above steps are in the order of patterning-> back etching-> bonding. Since the patterning is completed before the back etching, it is necessary to protect the pattern during the back etching.

FIG. 5 shows a back-etching jig in a conventional X-ray mask process disclosed in Japanese Utility Model Laid-Open No. 63-89238. This example relates especially to the protection of pattern surfaces.

In the drawing, 21 is a wafer surface pressing member,
22 is a recess, 23 is a wafer backside pressing member, 24 is an O-ring, 25 is a screwed portion, 26 is a handle for handling,
100 is an X-ray mask (wafer) in process. The X-ray mask 100 is sandwiched between the two members 21 and 23, and the O-ring 24 is used for sealing. The method of supplying the liquid is not particularly described, but it is presumed that the whole is attached to the etching tank.

FIG. 6 is a diagram for explaining a back etching method and a back etching end point detecting method described in Japanese Patent Laid-Open No. 3-105920. In the figure, 30 is a container, 3
1 is grease, 32 is a glass stand, 33 is a thermocouple, 34 is a recorder, 35 is a heater, 20 is an etching solution, 100
Is an X-ray mask in process.

Next, the operation will be described. Glass stand 32
The X-ray mask 100 is placed on the above, and the cylindrical container 30 is placed via the grease 31. Etching solution 20 in the container
And back etch. During the etching, the thermocouple 33 monitors the pattern surface temperature of the X-ray mask, and the completion of etching is known from the decrease in temperature.

[0009]

The problems associated with the above two back-etch methods will be described. First, in the structure shown in FIG. 5, since the O-ring 24 is used for sealing, a large pressure is locally applied, which may cause the O-ring mold to remain after the etching is completed. Further, in the configuration shown in FIG. 5, if the seal is incomplete, the etching liquid causes X-ray mask 10 due to capillary force or the like.
There was a problem that it was easy to get around to the front side of 0. Again 2
Since the two holding members 21 and 23 are screwed, there is a problem that it takes a lot of time to set the X-ray mask.

As shown in FIG. 6, a glass stand 32 is provided.
Since the X-ray mask 100 is in direct contact with the X-ray mask 100, the surface of the X-ray mask is easily damaged, and the back surface of the X-ray mask is contaminated because the grease 31 seals.

The present invention has been made for the purpose of solving the above-mentioned problems, and provides an X-ray mask capable of reliably back-etching a patterned silicon wafer with a simple jig structure. The purpose is to obtain a manufacturing method.

[0012]

A method of manufacturing an X-ray mask according to the present invention comprises a flat soft packing having a hole formed in the center thereof, the X-ray mask being processed being superposed downward on the pattern forming side. By stacking a soft packing similar to the above-mentioned soft packing on it, further stacking a perforating member on it, and filling the silicon packing with the etching liquid of the soft packing and the perforating member on the X-ray mask. , Back etch is performed.

[0013]

In the X-ray mask manufacturing method of the present invention,
The time required for back etch preparation can be greatly reduced, and according to the sealing method of the present invention, even if the sealing is incomplete, there is no possibility that the etching solution will flow around to the surface on the opposite side, so the patterning is completed. Even when the X-ray mask is back-etched, the pattern is not destroyed and a high yield can be maintained.

[0014]

EXAMPLES Example 1. FIG. 1 is a view showing an embodiment of the present invention, in which 1 is a silicon wafer, 2 is a membrane, and 3 is an absorber pattern. Reference numeral 7 indicates a window portion opened on the opposite side of the absorber pattern of the silicon wafer. 11 is a stand,
Reference numeral 12 is a flat plate-like soft packing having a hole in the center, 13 is a chemical resistant weight, 14 is a weight, and 20 is an etching solution for back etching.

Next, FIG. 1 will be described. In this manufacturing process, back etching is performed on the silicon wafer on which the absorber pattern is already formed. To briefly describe the steps up to here, first, the membrane 2 is formed on the silicon wafer 1 by a chemical vapor deposition method (CVD method). Thereafter, tungsten is deposited as an X-ray absorber material on the one surface by sputtering. Then, the absorber pattern 3 is formed through the steps of EB resist coating, EB exposure, and absorber etching. At any point during the above process, the central portion of the backside membrane is removed into a predetermined shape and size. This is due to the dry etching of the membrane. Through the above steps, the X-ray mask 1 shown in FIG.
00 is formed.

Next, the back etching process will be described. First, perforated soft packing 1 made of chemical resistant material
Place 2 on the base 11. The packing hole was made slightly larger than the back etch area. Then, the X-ray mask 100 in the process is placed on top of it so that the absorber pattern side faces down. Further, a soft packing 12, which also has a hole, a chemical-resistant weight 13, and a weight 14 are stacked on top of this in that order. The weights 13 and 14 also have holes. After that, the etching liquid 20 for silicon etching, which is measured with a pipette or the like, is poured into the recess formed by the soft packing 12 and the weights 13 and 14. In this embodiment, 20 cc of a mixed aqueous solution containing hydrofluoric acid and nitric acid was poured as an etching solution.
Approximately 5 to 2 depending on the composition and concentration of the etching solution
The etching of silicon is completed in about 0 minutes. No leakage of the etching solution was observed during the etching, but if the seal was incomplete and leakage occurred, the soft packing was smaller than the silicon wafer as shown in FIG. It does not go around the surface.
After the etching is completed, the procedure is reversed to remove it.

Example 2. In the above-described embodiment, the X-ray mask 100 is back-etched at the stage when the patterning of the absorber is finished. However, the same back-etching as in the above-mentioned embodiment is performed before the film formation and patterning of the absorber. May be. FIG. 2 shows a state of back etching in such a case. The X-ray mask 100 is placed on the soft packing 12 with the absorber pattern film forming side facing downward, and back etching is similarly performed.

In each of the above embodiments, the weights 13 and 14 having holes are stacked on the soft packing 12, but instead of the weights 13 and 14, a perforating member is stacked to form a similar concave portion. The same effect can be obtained even if the soft packing 12 is brought into close contact with the X-ray mask 100 using a spring or the like.

[0019]

As described above, according to the present invention, the X-ray mask in the process is overlaid on the plate-shaped soft packing having a hole in the center so that the pattern forming side faces downward, and the soft packing is placed on the X-ray mask. Back-etching is performed by stacking the same soft packing as above, further stacking a perforating member on the soft packing, and filling a silicon etchant in the recess formed by the soft packing and the perforating member on the X-ray mask. X
Since the line mask is manufactured, the back etching process can be easily prepared in a short time. Further, since the sealing is performed on a wide surface, the surface pressure is low and the surface of the X-ray mask is not contaminated. Further, even if the seal is incomplete and the liquid leaks, the etching liquid does not flow around to the surface opposite to the back-etched surface, so that the pattern surface is not damaged.

[Brief description of drawings]

FIG. 1 is an explanatory view illustrating an X-ray mask manufacturing method according to a first embodiment of the present invention.

FIG. 2 is an explanatory view illustrating an X-ray mask manufacturing method according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing an outline of an X-ray mask.

FIG. 4 is a process drawing showing the outline of the manufacturing process of the X-ray mask.

FIG. 5 is an explanatory diagram illustrating a conventional method for manufacturing an X-ray mask.

FIG. 6 is an explanatory diagram illustrating another conventional method for manufacturing an X-ray mask.

[Explanation of symbols]

 1 Silicon Wafer 3 Absorber Pattern 12 Soft Packing 13 Weight 14 Weight 20 Etching Solution 100 X-ray Mask During Process

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Moto Hashimoto 8-1-1 Tsukaguchihonmachi, Amagasaki City Mitsubishi Electric Corporation Central Research Laboratory (72) Inventor Yasuji Matsui 8-1-1 Tsukaguchihonmachi, Amagasaki Mitsubishi Central Research Laboratory of Electric Co., Ltd.

Claims (1)

[Claims] 1. An X-ray mask in the process is overlaid downward on a plate-like soft packing having a hole in the center, and a soft packing similar to the above soft packing is overlaid thereon, and further A method of manufacturing an X-ray mask, characterized in that back-etching is performed by stacking a perforation member on the top and filling a recess formed by the soft packing and the perforation member on the X-ray mask with a silicon etching solution. .