JPH0795506B2 - Method for manufacturing mask for X-ray exposure - Google Patents

Description

The present invention relates to an X-ray exposure mask, and particularly to an X-ray exposure mask suitable for easily and reproducibly forming an X-ray absorber pattern having a minute dimension of 1 μm or less. The present invention relates to a line exposure mask and a method for manufacturing the same.

[Conventional technology]

The accuracy of the absorber pattern that shields X-rays in X-ray exposure is a direct factor that determines the pattern transfer accuracy,
Its accuracy is extremely important. Especially the pattern size is 1
When the thickness is less than or equal to μm, it is necessary to accurately form the absorber pattern not only in a planar manner but in a three-dimensional manner. That is,
When a taper is generated on the side surface of the absorber pattern in a pattern of 1 μm or less, X-rays are transmitted through the taper portion and the pattern transfer accuracy is significantly degraded. Therefore, the side surface of the absorber pattern needs to be formed vertically.

For this purpose, a method for producing an absorber pattern using a plating method has been conventionally proposed. [GE Georgiou et
al, SPIE) 471, page 96 (1984)]. The outline will be described with reference to FIG. An electrode 6 for plating is laminated on the support film 1 which transmits X-rays, and a mask pattern 2 for plating is formed on the electrode 6. Next, Au plating is performed to deposit Au7 between the mask patterns (FIG. 7B). Then, the mask pattern 2 is removed (FIG. 7C), and the exposed portion of the plating electrode 6 is removed to obtain an absorber pattern 7 (FIG. 3D).

According to this method, the side surface of the absorber pattern 7 can be made vertical by forming the side surface of the plating mask pattern 2 vertically.

[Problems to be solved by the invention]

Thus, according to the conventional method using the plating method, it is possible to make the pattern side surface vertical. However, this method complicates the manufacturing process, and it is not easy to manufacture a fine pattern with good uniformity. That is, it is necessary to control the plating conditions in detail in order to electrodeposit Au on a fine region of 0.5 μm or less with good uniformity.
There is a problem with reproducibility. Further, the conventional method using the plating method complicates the process, and the manufactured X-ray mask becomes expensive.

An object of the present invention is to easily and reproducibly manufacture an absorber pattern having vertical side surfaces and a minute dimension.

[Means for solving problems]

Therefore, in the present invention, the absorber pattern is produced by the method shown in FIG. That is, after the resin pattern 2 having vertical side surfaces is formed (FIG. 7A), Au is applied to the entire surface of the mask.
3, 3'is attached ((b) of the same figure). Here, Au is deposited by vapor deposition or sputtering. Next, the resin film 4 is applied to the entire surface of the mask ((c) in the figure). At this time, the surface of the resin film 4 becomes substantially flat due to the fluidity of the resin solution. Then Ar
The Au 3 ′ on the resin film 4 and the resin pattern 2 is etched by ion etching using ions 5. At this time, Au3 between the resin patterns remains without being etched, and this Au pattern becomes the absorber pattern.

[Action]

Here, since Au is deposited by vapor deposition or sputtering, it is faithfully deposited on the base substrate. Therefore, no matter how small the resin pattern spacing is, Au is deposited in that region. As described above, according to the present invention, it is possible to easily manufacture a pattern of a fine dimension absorber having a size of 0.5 μm or less, which is difficult by the plating method. Further, the resin pattern used in the present invention is produced by electron beam drawing or a multi-layer resist method and has extremely high precision and the side surface of the pattern is vertical. Therefore, the absorber pattern obtained by the present invention has a vertical side surface and a high precision.

Further, in the present invention, a simple and reproducible process of vapor deposition, polymer resin coating and ion etching is used after the resin pattern is formed. The resin pattern 2 remaining after the ion etching is made of a light element and transmits X-rays. Therefore, it can be left as is and the process is simplified. As described above, according to the present invention, the absorber pattern can be produced by a simple and reproducible process.

〔Example〕

 Embodiment 1 An embodiment of the present invention will be described below with reference to FIG.

A BN film (film thickness 0.5 μm) is formed by the chemical vapor deposition method as the X-ray mask support film 1. Next, the polyimide film is the lower resin layer (film thickness 1.5 μm) and Ti is the intermediate layer (film thickness 0.1 μm).
Resin pattern 2 was obtained by a three-layer resist process using electron beam drawing with PMMA (polymethylmethacrylate) as the upper resist layer (film thickness 0.8 μm).

Then, by vacuum evaporation, Au / Mo3 and 3 '(film thickness 0.8 μm / 0.0
2 μm; Mo is vapor-deposited with an adhesive layer with the base), and further resin film 4
Then, a novolak resist (film thickness: 2 μm) was formed by coating baking. After that, Au 3'on the resin film 4 and the resin pattern is formed by ion milling using Ar ions 5.
Etching. Here, the end point of etching is the time when Au3 'on the resin pattern disappears, but the determination can be easily made visually. At this time, Au3 between the resin patterns remains without being etched, and this Au pattern 3 becomes an absorber pattern.

Example 2 Instead of the resin pattern of Example 1, a SiO ₂ pattern was used in this example. The production of this SiO ₂ pattern is as follows. A SiO ₂ film with a thickness of 1.5 μm is formed by chemical vapor deposition. Next, etching of SiO ₂ is performed using NPR (trade name of Hitachi Chemical Co., Ltd.) formed by electron beam drawing as a mask. Etching is performed by reactive ion etching (RIE) using CF ₄ type gas, and the obtained SiO ₂ pattern has vertical side surfaces.

In this example, Mo was used as the absorber instead of Au in the previous example. An electron beam vapor deposition apparatus was used for the deposition of the Mo film, and the film thickness was 1 μm. After depositing a Mo film on the SiO ₂ pattern, an absorber pattern 3 was obtained by the same method as in Example 1.

Thus, in this example, the SiO ₂ pattern was used instead of the resin pattern. This is because SiO ₂ is a light element and X-rays are easily transmitted, and SiO ₂ is a material that is easily etched and is suitable for microfabrication. Other materials that satisfy such conditions include SiN and Si. Mo was used as the absorber in this example. This is because Mo is a heavy element and has an excellent stopping power for X-rays, and etching by ion etching can be easily performed. Other materials that satisfy such conditions are P
There are t, W, Ta, Ag, Pd, Nb, Zn, Cm, Ni, Co, Fe or alloys thereof.

Example 3 In this example, TaOx formed by spin coating and baking was used as the absorber. As TaOx, an organic Ta compound solution (for example, Atron Ta: trade name of Nippon Soda Co., Ltd.) was applied, and then baked at 300 ° C. in the air to form an oxide. The film thickness was 1 μm.

The steps other than the TaOx film forming the absorber are the same as those in the first embodiment.

〔The invention's effect〕

According to the present invention, it is possible to manufacture an absorber pattern with high fidelity by using a highly accurate resin pattern or the like having a vertical pattern side surface. Therefore, the absorber pattern obtained is a pattern with a highly accurate pattern side surface. As described above, by using the absorber pattern according to the present invention, it is possible to form a minute dimension pattern of 0.5 μm or less in X-ray exposure.

[Brief description of drawings]

FIG. 1 is a process drawing showing an embodiment of the present invention, and FIG. 2 is a process drawing showing a conventional method. 1 ... Support film, 2 ... Resin pattern, 3, 3 '... X-ray absorber, 4 ... Polymer resin, 5 ... Ar ion, 6 ... Electrode for plating, 7 ... Au plating.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-55-16423 (JP, A) JP-A-57-170530 (JP, A) JP-A-58-61633 (JP, A)

Claims (1)

[Claims] 1. A step of forming a resin pattern on a support film in an X-ray exposure mask, a step of depositing Au on the entire surface of the mask by vapor deposition or sputtering, and a step of applying a resin film on the entire surface of the mask. A method for manufacturing an X-ray exposure mask, comprising the step of etching Au on the resin film and the resin pattern by ion etching using an inert gas.