JPS5914638A - Mask for exposing x-ray and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain ultrafine X-ray exposure mask pattern from an X-ray absorber layer made of Ta by reactively sputter etching with CBrF3 gas with high molecular material or SiO2 as a mask. CONSTITUTION:Glass 2 is superposed on an Si substrate 1, and X-ray absorber 14 of Ta is deposited in a thickness of approx. 4,000Angstrom . A photoresist mask 15' is coated, and a layer 14' is formed by reactively sputter etching with CBrF3 gas. Subsequently, a mask is covered on the substrate 1, and an Si layer 1' is formed by etching. According to this structure, an X-ray exposure mask which has ultrafine size of submicron size and vertical side surface can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention can be used in manufacturing semiconductor integrated circuits.
Related to X-ray exposure masks and their manufacturing methods.

Conventionally, mask binding for X-ray exposure and light has been proposed having a structure obtained by the following manufacturing method.
1. That is, as shown in FIG. 1, a substrate 3 consisting of a wafer 1 made of, for example, Sl and a substrate body 2 made of, for example, glass having a property of transmitting X-rays is prepared in advance. On the substrate 3 (7) of the substrate body 2, an X-ray absorber layer 4 made of AL+ is formed (FIG. 1B).

Next, a metal H made of Ti, Ta, etc. is placed on the xm absorber W4.
5 (Figure 1C).

Next, that money 1! A photoresist layer 6 is formed on the WJ 5 (FIG. 1D), and then a desired pattern is formed from the photoresist layer 6 by an exposure process with a desired pattern on the photoresist layer 6, followed by a development process. (FIG. 1E).

Next, by etching the metal layer 5 using, for example, CI4 plasma using the photoresist layer 6' as a mask, a metal layer 5' having a desired pattern is formed from the metal layer 5 (the first Figure F).

Next, the photoresist layer 6' was removed from above the metal layer 5', and the X-ray absorber layer 4 was irradiated with ions using an inert gas such as Ar gas, using the metal layer 5' as a mask. , by ion etching treatment, XI @ absorption layer 4
From this, an X-ray absorber layer 4' having a desired pattern is formed (FIG. 1G).

Thereafter, by etching the wafer 1 of the substrate 3 using a mask, a wafer 11' is formed around the wafer 1 (FIG. 11), thus,
A desired X-ray exposure mask is obtained.

As described above, the conventionally proposed X-ray exposure masks and their manufacturing methods have been clarified.

In the case of the conventional X-ray exposure mask described above, the X-ray absorber layer 4' having the desired pattern is made of AU, so the X-ray absorber layer 4' does not absorb X-rays (especially soft X-rays). Absorbs well.

Therefore, the conventional X-ray exposure mask described above is useful as an X-ray exposure mask.

However, in the case of the above-mentioned conventional X-ray exposure mask manufacturing method for obtaining the above-mentioned conventional X-ray exposure mask,
The X-ray absorber layer 4' having a desired pattern is formed by ion etching the X-ray absorber layer 4 of 80 mm using the metal layer 5' having the desired pattern as a mask. During the ion etching process, the reason is that 80 adheres to the side surface of the metal layer 5', or the metal layer 5' is etched from the side surface, and the pattern of the metal layer 5' becomes smaller than the initial pattern. The X-ray absorber layer 4' is formed to have side surfaces inclined at about 75 degrees.

Therefore, in the case of the above-mentioned conventional X-ray exposure mask and its manufacturing method, the xIm absorber layer 4' having a desired pattern is
It has been extremely difficult to form a fine pattern on the order of submigration.

Therefore, in the case of the conventional xis+im optical mask and its manufacturing method, even if semiconductor integrated circuits are manufactured by applying them, it is extremely difficult to manufacture the semiconductor integrated circuits into fine patterns on the submicron order. It had drawbacks such as being difficult.

Therefore, the present invention provides a novel xsi
+ We aim to propose an exposure mask and its manufacturing method.

As a result of various experiments, the present inventors found that although the X-ray exposure mask apparently has the configuration described above in FIG. 1H, the X-ray absorber 114' having the desired pattern is AL+. Even if the X-ray exposure mask is made of Ta, the X-ray absorber li! As in the case where 4' is made of Au, it absorbs X-rays (particularly soft X-rays) well, and therefore the X-ray exposure mask in this case is similar to the conventional It has been confirmed that this material is useful as a mask for X-ray exposure in the same way as a mask.

In addition, as described above, apparently, X as described above in FIG.
It has the structure of a mask for radiation exposure, but instead of the X-ray absorber I4' having the desired pattern being made of AIJ,
In the case of an X-ray exposure mask made of Ta, the Ta constituting the X-ray absorber layer 4' in this case is Au.
Since the Xa exposure mask in this case is cheaper than the conventional X11 exposure mask described above in FIG.
We have now confirmed that it can be provided at a low price.

Further, in the configuration of the conventional X-ray exposure mask described above with reference to FIG. The configuration of the X-ray exposure mask described above in FIG. In the case of an X-ray exposure mask similar to the above, the layer made of a polymer material or SiO formed on the X-ray absorber layer 4' in this case is such that the X-ray absorber layer 4' absorbs X-rays. In this case, the X-ray exposure mask acts as an electron absorber layer that absorbs electrons such as Auger electrons and photoelectrons that are to be emitted to the outside from the X-ray absorber 14'. It exhibits a much higher mask contrast than the conventional X-ray exposure mask shown in FIG.
We have confirmed that this product is superior to line exposure masks.

Furthermore, in the structure of the conventional X-ray exposure mask described above in FIG. mask or the conventional X described above in FIG.
As described above, the X-ray absorber layer 4' having a desired pattern and the structure of the mask for radiation exposure is made of Ta, and in this case, on the X-ray absorber layer 4' made of Ta, , an X-ray exposure mask having the same configuration as the X-ray exposure mask described above in FIG. In the case of manufacturing the In this case, the layer made of a polymeric material or SiO as the mask described above will be smaller than the initial pattern, and the X-ray absorber layer 4' will be formed with an inclination. Therefore, the X-ray absorber layer 4' can be easily formed into a fine pattern on the submicron order without having the above-mentioned drawbacks of the manufacturing method of the conventional X-ray exposure mask. Therefore, when applied to the production of semiconductor integrated circuits, it is confirmed that the semiconductor integrated circuits can be easily produced with fine patterns on the submicron order. I came to the conclusion.

Therefore, the present inventors have proposed the invention described in the claims.

Next, accompanied by Figure 2, 'xI! A first embodiment of a mask for I exposure and an embodiment of its manufacturing method will be described in detail in the first embodiment of a method of manufacturing an x*n light mask according to the present invention.

As described above with reference to FIG. 1, a substrate 3 is prepared in advance, in which a substrate body 2 made of, for example, glass and having a property of transmitting X-rays is placed on a wafer 1 made of, for example, 3i. ), on the board body 2 of the board 3, there is an
The line absorber layer 14 was formed to a thickness of 8000 mm by vapor deposition, sputtering, ion plating, etc. (FIG. 2B).

Next, a photoresist layer is formed on the X-ray absorber layer 14 as an electron absorber layer 15 made of a polymer material by a spin code method (FIG. 2C). An electron absorber layer 15' having a desired pattern was formed from the electron absorber layer 15 by an exposure treatment having a desired pattern and a subsequent development treatment (second
Figure D).

Next, the electron absorber layer 15 for the X-ray absorber 1114
In a reactive sputter etching process using CBrF3 gas as a mask, an X-ray absorber made of Ta having a desired pattern is removed from the X-ray absorber layer 14 [114
' was formed (Fig. 2E).

Thereafter, in the same manner as described above with reference to FIG. 1, by etching the wafer 1 of the substrate 3 using a mask, a wafer 1' consisting of the wafer 1 and its surrounding portion is formed (FIG. 2F). In this way, the intended X-ray exposure mask was obtained.

Next, with reference to FIG. 3, a second embodiment of the Xta exposure mask according to the present invention and an embodiment of its manufacturing method will be described. Let me explain in detail.

A substrate 3 having a substrate body 2 disposed on a wafer 1, similar to that described above in FIG. 2, is prepared in advance. In the same manner as described above, an X-ray absorber layer 14 made of Ta' was formed (FIG. 3B).

Figure 3C).

Next, a photoresist layer 26 is formed on the electron absorber layer 25 (FIG. 3D).
A photoresist layer 26' having a desired pattern was formed from the resist layer 26 on the photo resist layer 1 by an exposure process having a desired pattern and a subsequent development process (FIG. 3E).

Next, the photoresist layer 2 is applied to the electron absorber layer 25.
An electron absorber layer 25' made of SiO having a desired pattern was formed from the electron absorber layer 25 by etching using the electron absorber layer 5' as a mask (FIG. 3F).

Next, the four resist layer 26' is applied to the electron absorber layer 25'.
Then, the X-ray absorber layer 14 is subjected to a reactive sputter etching process using C3rF gas using the electron absorber B25' as a mask.
4, an X-ray absorber layer 14' made of Ta and having a desired pattern was formed (FIG. 3G).

Thereafter, the wafer 1 of the substrate 3 is removed in the same manner as described above in FIG.
By etching processing using a mask, a woofer' consisting of the woofer and its surroundings was formed (FIG. 3H), thus obtaining the intended X-ray exposure mask.

Next, with reference to FIG. 4, a third embodiment of the XSa exposure mask according to the present invention and an embodiment of its manufacturing method will be described. Let me explain in detail.

Similar to that described above in Figure 2A, Uef? 1. Prepare in advance a substrate 3 with a substrate body 2 arranged thereon (FIG. 4A), and place an X-ray beam of Ta on the substrate body 2 of the substrate 3 in the same manner as described above in FIG. 2B. An absorber 1114 was formed (FIG. 4B).

Next, on the X-ray absorber layer 14, an inter-polymer layer having high resistance to the reactive sputter etching treatment described later is formed as an electron absorber layer 27 by various methods known per se. (Figure 4C).

Next, a photoresist layer 28 is formed on the electron absorber layer 27 (FIG. 4D), and then the photoresist layer 28 is subjected to an exposure process having a desired pattern, followed by a development process. From 28, a photoresist layer 28' having a desired pattern was formed (
Figure 4E).

Next, the photoresist layer 2 for the electron absorber layer 27 is
Using 8' as a mask, a metal evaporation process consisting of, for example, ■i is performed to form an electron absorber I! Photoresist layer 2 on 27
A gold m layer 29a is formed on the region where 8- is not formed (FIG. 4F). This metal layer 298 has a pattern that is inverted with respect to the pattern of the photoresist layer 28'. In this case, a metal layer 29b made of the same metal as the gold R layer 29a is formed on the photoresist layer 28'.

Next, the photoresist layer 28' and the gold Rm29b formed thereon are removed by dissolving the photoresist layer 28' from above the electron absorber layer 27, that is, by removing the photoresist layer 28' from above the electron absorber layer 27. was removed by (Fig. 4G).

Next, by etching the electron absorber layer 27 using the metal layer 29a as a mask, an electron absorber layer 27' made of a polymer material and having a desired pattern was formed from the electron absorber layer 27. (Figure 4H).

Next, the metal layer 29a is removed from above the electron absorber layer 27', and then the XS* absorber layer 14 is subjected to a reactive sputter etching process using C B rF3 gas using the electron absorber layer 27' as a mask. As a result, from the X-ray absorber layer 14, the X-ray absorber layer 1 made of Ta has a desired pattern.
4' was formed (Fig. 4 ■).

Thereafter, in the same manner as described above with reference to FIG. 2, the wafer 1 of the substrate 3 is etched using a mask to form a wafer 1' consisting of the entire wafer 1 and its surrounding portion. ), thus the desired X-ray exposure mask was obtained.

The embodiments of the X11A exposure mask and method for manufacturing the same according to the present invention have been clarified above.

According to the above-described X-ray exposure mask according to the present invention, the X-ray absorber layer 14'' having the desired pattern is made of Ta, so as described above, it is useful as well as the conventional X-ray exposure mask. It has the characteristics of being inexpensive as well as being inexpensive.

Further, according to the XIIQ exposure mask according to the present invention described above, the X-ray absorber layer 14-
is made of Ta, and the X-ray absorber layer 14 is made of Ta.
- the upper part is made of polymeric material (as shown in the embodiments of Figures 2F and 4J) or 5ift' (3
As shown in the embodiment of FIG. 11), an electron absorber layer is formed, so as mentioned above, it is superior to conventional X-ray exposure masks. It is.

Furthermore, as shown in FIG. 2F, FIG. 3H, and FIG. 4J, the X-ray absorber layer 1 of the X-ray exposure mask according to the present invention is shown in FIG.
4' thickness D (μm), MO-L line (wavelength 5.
When mask contrast was measured using the Si- line (wavelength 7.13 A) and the AI- line (wavelength 8.34 A), the results shown in Figure 5 A, B, and C, respectively, were obtained. Obtained. From this result, the mask contrast was set to 1
To obtain a value of 0, the thickness D of the X-ray absorber layer 14- should be 0.
It is clear that the thickness should be about 8 μm.

Further, according to the method for manufacturing an X-ray exposure mask according to the present invention described above, the X-ray absorber layer 14' having a desired pattern
with a layer made of polymer material or SiO as a mask, C
Since the X-ray absorber layer made of Ta is formed by reactive sputter etching using 'Br'F gas, the characteristic X-ray exposure mask described above can be
As mentioned above, there are people who can easily form an X-ray exposure mask without having the drawbacks of the above-mentioned conventional methods for manufacturing an X-ray exposure mask. It has characteristics.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a conventional X-ray exposure mask and its manufacturing method showing sequential steps in the conventional X-ray exposure mask manufacturing method. FIG. 2 shows a first embodiment of an X-ray exposure mask according to the present invention and a method for manufacturing the same, and shows a line diagram of sequential steps. FIG. FIG. 3 shows a second embodiment of the φ X-ray exposure mask according to the present invention and a method for manufacturing the same. FIG. FIG. 4 is a line cross-sectional view of sequential steps showing a third embodiment of the X-ray exposure mask and its manufacturing method according to the present invention. It is. FIGS. 5A, B, and C show the M-L line, Si-line, and It is a figure which shows the result of measuring the mask contrast using the line for AI-. 1.1'...Water 1 2......Board body 3...Board 14... - X-ray absorber layer 14' made of Ta...Ta having a desired pattern
X-ray absorber layer 15 made of......8 Electron absorber layer 15' made of a molecular material...... Made of a polymeric material having a desired pattern Electron absorption resting layer 25......Electron absorber layer 2 made of SiO 25'......5i having a desired pattern
Electron absorber layer 27 made of O1...... Electron absorber layer 27' made of polymer material...... Made of polymer material having a desired pattern Electronic absorber layer applicant Nippon Telegraph N! ! , Public Corporation 111 Figure 1 Figure 2 Figure 2 Figure 2 Cζl Figure 3 Figure S3 Figure C' Figure 4 Figure 1 to 5 Figure A D (am)

Claims (1)

[Claims] 1. An X-ray exposure mask comprising an X-ray absorber layer having a desired pattern formed on a substrate, wherein the X-ray absorber layer is T, An X-ray exposure mask characterized by a.・2. Having a desired pattern on the substrate. In the X-ray exposure mask formed with an X-ray absorber layer, an electron absorber layer is formed on the X-ray absorber layer, the X-ray absorber layer is made of Ta, An X-ray exposure mask characterized in that the electron absorber layer is made of a polymeric material or 5tO2. 3. A step of forming an X-ray absorber layer made of Ta on the substrate; a step of forming an electron absorber layer made of a polymeric material or 5tO2 having a desired pattern on the X-ray absorber layer; A reactive sputter etching process is performed on the X-ray absorber layer using CBrF3 gas using the electron absorber layer as a mask to form an xti+ absorber layer made of Ta having a desired pattern from the X-ray absorber layer. A method for manufacturing an X-ray exposure mask, comprising the steps of: