JPS63136622A - X-ray exposure mask - Google Patents

Abstract

PURPOSE:To prevent a mask from being deformed due to the stress of an X-ray absorbing pattern by setting the stress of a pattern protecting film buried with the pattern and the stress of the pattern to an equal values. CONSTITUTION:SiN films are formed by a CVD unit on both side surfaces of a mirror-polished Si wafer substrate 6, one side surface is formed with an X-ray transmissible thin film 2 and the other side surface is removed by etching with a photoresist pattern as a mask to form a protecting film 5. After an X-ray absorbing pattern material layer having a tensile stress made of a W film or a Ta film is formed on the film 2, a resist pattern is formed, for example, by a normal electron beam exposure method, and with it as a mask it is dry etched to form an X-ray absorbing pattern 3. Then, a polyimide pretreated film is formed by rotatably coating from the surface to which the pattern 3 is secured. A stress of a range for satisfying the unequality formula ¦(sigma1-sigma2)/sigma2 ¦ <=0.5 is provided on the X-ray transmissible thin film formed with the pattern, wherein the sigma1 is the stress (dyn/cm<2>) of the pattern protecting film, and the sigma2 is the stress (dyn/cm<2>) of the X-ray absorbing pattern. If it falls in the above range, it can substantially prevent the mask from being deformed due to the stress of the pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an X-ray exposure mask used in an X-ray exposure apparatus that transfers fine patterns with high precision.

[Conventional technology]

The X-ray exposure method is known as a technique that uses soft X-rays with a wavelength of 4 to 50 A as a radiation source and is capable of transferring submicron fine patterns.

An example of a conventional X-ray exposure mask is an X-ray exposure mask 1 consisting of an acidic pattern 3 and a protective film 7 used when partially removing an 8i Uni8 substrate.

[Problem that the invention seeks to solve]

It is generally known that mask distortion occurs due to the stress of an X-ray absorbing pattern, for example, H, Mulle
r, P, Ti5her, and W, Win
dbracke, “Influence of absorber stress on X-ray mask accuracy”
er 5tress on the precisio
nof X-ray masks ), (Jun
al of Vacuum and 8ci-ance
Technology, B4 (1),
Jan, /Feb, l 9 f35゜P, 230)
It is stated in

Therefore, in the past, the mask distortion due to the stress of the X@absorbing pattern was large, and the positional accuracy or long-width/teeth accuracy required for X-ray exposure masks for ultra-L8I devices was often not met. .

So, what are the problems that the present invention attempts to solve?

X that prevents mask distortion due to stress in the X-ray absorbing pattern
An object of the present invention is to provide a mask for line exposure.

[Means for solving problems]

As a result of research to solve the above problems, the inventor of the present invention found that an X-ray absorbing pattern is provided on one side of an X-ray transparent thin film, and a support frame is provided on the other side of the X-ray transparent thin film. In an X-ray exposure mask equipped with a We have discovered that it is possible to prevent a decrease in M degree, and based on this finding, we have developed an X-ray exposure mask that is provided with a radiation-absorbing pattern and that has a support frame on the other side of the X-ray transparent thin film. , a patterned protective film having a stress within a range that satisfies the following inequality is provided on the surface of the X-ray transparent thin film provided with the XR-absorbing pattern, and the absorbing pattern is embedded within the patterned protective film.
Mask for line exposure.

Note that σ1 is the stress of the pattern protective film (dyn/d)
@σ2 indicates the stress (dyn/J) of the X-ray absorbing pattern. ” is the gist.

In the present invention, within this range, mask distortion due to stress in the X@ absorbing pattern is substantially prevented.

Next, in the present invention, for example, CV
Separate sN4.19iN and 8iC were formed on one surface of the Su81 Unihachi substrate by the D method or the sputtering method.

Thickness 1 consisting of a single layer or a composite layer of BN, etc., or polyimide formed by a spin coating method and having tensile strength.
Thin films of ~6 μm can be applied.

Next, as the X-ray absorptive pattern, Au, W, Ta
.

After forming an X-ray absorbing pattern material layer with a thickness of 0.2 to 1.5 µm mainly composed of heavy metals such as Mo on an X-ray transparent thin film by vapor deposition, sputtering, or CVD, drying and etching are performed. Cr, Ni, etc. with a thickness of 50 to 200 AtD on an X-ray transparent thin film.
, Ti, etc. and Au with a thickness of 200 to 600 A are sequentially deposited or sputtered to form a plating base layer, and then the surface of this plating base layer is covered with a resist pattern with openings in the portion corresponding to the X-ray absorbing pattern. Then, the openings of the resist pattern were plated with Au.

After that, the resist pattern can be removed and a new one can be applied. Incidentally, after forming the XNA@absorbent pattern, unnecessary portions of the plating base layer can be easily removed by, for example, a sputtering method using irradiated gas.

Next, as a pattern protective film, a polymer film such as polyimide, polymethyl methacrylate (PMMA), etc. can be applied by a 1g1 transfer method.

In addition, in the present invention, CVD is applied on this patterned protective film.
An inorganic material layer having a thickness of 0.05 to 0.5 μm made of an inorganic material such as 8o02°Bi@N4 may be provided by a method or a sputtering method.

[For production]

Stress (σ2) in the pattern protective film with stress (σ1)
By embedding an X-ray absorbing pattern with
A balance is obtained between the stress of the radiation absorbing pattern and the stress of the pattern protective film, and mask distortion due to the stress of the X-ray absorbing pattern is substantially prevented.

〔Example〕

The above-mentioned present invention will be explained in more detail by giving examples below.

FIGS. 1(a) to (dl K) are schematic cross-sectional views showing the manufacturing process of one embodiment of the present invention.
1 is a sectional view of an X-ray exposure mask manufactured according to this example.

First, as shown in FIG. 1(a), a tensile stress of 0.8 x 10' to 2, OX 1, for example, is applied to both sides of the 84 unihachi substrate 6, which has been mirror-polished to a thickness of 0.3 to 4 mm, using a CVD apparatus.
A 2 amo siN film having a thickness of 0' dyn/cj is formed, and unnecessary parts are removed by etching using an X-ray transparent thin film 2 on the negative side and a photoresist pattern on the other side as a mask. A film 5 was formed.

As shown in Figure 1 (bl), the X-ray transparent thin film 2 is made of a KW film or a Ta film and has a tensile stress of I x 10.
' After forming a 1 μm thick X-ray absorptive pattern material layer with dyn/cIl by CVD method or sputtering method, a resist pattern is formed by, for example, ordinary electron beam exposure method, and then dry etching is performed using the resist pattern as a mask. , an X-ray absorbing pattern 3 was formed by ticking.

Furthermore, after forming a polyimide precursor film by spin coating on the side of the X-ray transparent thin film 2 on which the X-ray absorbing pattern 3 is fixed, heat treatment is performed successively at 90°C for 30 minutes and at 150°C for 30 minutes. By this, tensile stress 1x 10”d
FIG. 1(e) shows a state in which a polyimide film having a thickness of 3 .mu.m having yn/- is formed.

Here, the tensile stress of an X-ray absorptive pattern with a thickness of 1 μm is lX10"dyn/-, and a pattern within a thickness of 1 μm on the X-ray transparent thin film surface in an area where this X-ray absorbing pattern is not present. The tensile stress of the maintenance film is I x 10”
Since dYn/cd, two stress values are set so that the stresses in the thickness direction of the X-ray absorbing pattern are balanced.

Finally, as shown in FIG. 1(d), the portion of the 8i wafer substrate 6 that was not protected by the protective film 5 was etched away from the back surface to form a window and a supporting film 4 made of 8i.

During this etching, Teflon is used to protect the X-ray absorbing pattern and pattern protection film.

Using a jig consisting of an 0-ring, etc., use a 20 to 30 inch KOH aqueous solution or HF: HNO! :
By using an HF-based mixed solution of CH, C00H = 1:3:1, some parts of the 8i Uni8 board can be processed better.

Tick can be removed.

As described above, a part of the X-ray transparent thin film 2 has the X-ray absorbing pattern 3 and the support frame 4 on the other side, and the side of the X-ray transparent thin film on which the X-ray absorbing pattern is formed is An X@ exposure mask 1 as shown in FIG. 1(d) in which a pattern protection film 7 is formed and a CX-ray absorbing pattern is embedded.
was gotten.

When Xf1 exposure was performed using the mask of the above example, an image with high positional accuracy, long visibility, and high accuracy could be printed.

As another example, as shown in FIG.
tron Raonance (electron cyclotron resonance) type plasma CVD equipment to a thickness of 0.1μ
An X-ray beam is formed by forming an inorganic material layer 8 made of 84@N4 film or 8i02 film, and fixing a reinforcing frame 9 made of Vilex glass or the like to the supporting frame 4 via an Evokin adhesive layer 10, for example. There is an exposure mask 1.

〔Effect of the invention〕

As detailed above, the X#lA exposure mask according to the present invention prevents mask distortion caused by the stress of the X-ray absorptive pattern, so X-ray exposure with high positional accuracy, long beam, and long beam accuracy is possible. It is possible.

[Brief explanation of the drawing]

1(a) to d) are cross-sectional views showing the manufacturing process of an embodiment of the present invention, FIG. 2 is a cross-sectional view showing another embodiment of the present invention, and FIG. 3 is a conventional xii optical mask. FIG. 2 is a sectional view for explaining. 1......X-ray exposure mask 2...
...X-ray transparent thin film 3...X-ray absorptive pattern 4...
...Support frame 5...Substrate protective film
(a) 6......8i wafer substrate 7...Pattern protective film 8...Inorganic material layer 9...・Reinforcement frame
(b) 10...Adhesive layer (d) Figure 1

Claims (2)

[Claims] (1) In an X-ray exposure mask in which an X-ray absorbing pattern is provided on one side of an X-ray transparent thin film and a support frame is provided on the other side of the X-ray transparent thin film, An X-ray exposure mask characterized in that a patterned protective film having a stress within a range satisfying the following inequality is provided on a patterned X-ray transparent thin film surface, and an absorptive pattern is embedded within the patterned protective film. . Note |(σ_1-σ_2)/σ_2|≦0.5 However, σ_1 is the stress of the pattern protective film [dyn/cm^
2], σ_2 is the stress of the X-ray absorbing pattern [dyn/c
m^2]. (2) The X-ray exposure mask according to claim 1, characterized in that an inorganic material layer is formed on the patterned protective film.