JP2971657B2 - X-ray exposure mask and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray exposure mask for selectively transmitting X-rays according to a pattern and a method of manufacturing the same.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view showing the structure of a conventional X-ray exposure mask. In FIG. 3 , (1) is a support frame of the X-ray mask, (2) is a membrane, and
(1) is usually made of silicon having a thickness of about 500 μm to 5 mm, and the membrane (2) is usually made of silicon carbide (S) having a thickness of about 2 μm.
iC) or silicon nitride (SiN). (1
3) is a coated oxide film made of SiO ₂ having a thickness of 0.05 to 0.15 μm, and (4) is 0.5 to 1.0 μm to be an X-ray absorber.
Of tungsten.

[0003] Next, a manufacturing method of a conventional X-ray exposure mask will be described with reference to manufacturing process diagrams of Figure 4. First, FIGS. 4 (a)
As shown in (1), a resist (electron beam resist: EB resist) (6) having an electron beam sensitivity of about 0.5 to 1.5 [mu] m is applied on tungsten to be the X-ray absorber (4). 4 those of the configuration shown in (a) is attached to an electron beam exposure apparatus, selectively exposed according to a desired pattern. Then, by attaching the developer, as shown in FIG. 4 (b), to form a pattern by EB resist. Next, attached to the reactive ion beam etching apparatus having a configuration shown in FIG. 4 (b), a gas mainly containing sulfur hexafluoride (SF _6), is processed by etching tungsten.

At the time of this tungsten etching, the coating oxide film (13) functions as a membrane protective film. Finally, by removing the EB resist in an oxygen plasma, X-rays exposure mask shown in FIG. 4 (c) is completed.

[0005]

In a conventional mask for X-ray exposure and its manufacturing process, SF ₆ gas is used when etching tungsten which is an X-ray absorber (4).
In this case, there is a problem that the etched tungsten pattern is undercut with respect to the resist shape serving as a mask, does not become a vertical pattern, and is not etched as desired.

An object of the present invention is to provide an X-ray exposure mask having a desired pattern in which a vertical undercut is not formed, and a method of manufacturing the same. I do.

[0007]

That is, an X-ray exposure mask according to the present invention is an X-ray exposure mask using tungsten as an X-ray absorber, which becomes a mask when processing tungsten on the upper surface of tungsten. having a chromium film or a titanium film, and having an indium oxide scan's serving as a base protective film during processing of tungsten on the lower surface of the tungsten.

Further, the method of manufacturing an X-ray exposure mask according to the present invention is characterized in that tungsten is processed by dry etching using a mixed gas of SF ₆ and CHF ₃ using a chromium film or a titanium film as a mask. .

[0009]

In the method of manufacturing an X-ray exposure mask according to the present invention, a mixed gas of SF ₆ and CHF ₃ is used as an etching gas for tungsten as an X-ray absorber. By mixing CHF ₃ with SF ₆ gas, a vertically etched shape of the X-ray absorber can be obtained.

[0010] However, the addition of CHF _3,
Since the mask cannot achieve a selectivity with resist, chrome
Alternatively , titanium is used as an etching mask. Further, also by adding a CHF _3, conventional for the bottom coating oxide film that was acting as a protective film (13) is not a membrane protective film, using the I TO (indium tin oxide) in place of this.

Hereinafter, the X-ray exposure mask of the present invention will be described in detail. In FIG. 1, (1) is an X-ray mask support frame, and (2) is a membrane.
The support frame (1) is made of silicon having a thickness of about 500 μm to 2 mm, and the membrane (2) is made of silicon carbide (Si) having a thickness of about 2 μm.
C) or silicon nitride (SiN).

[0012] (3) is a base protection film for protecting the membrane (2) when the etching of the X-ray absorber (4) is manufactured by depositing acid indium tin (ITO) by sputtering or the like. (5) is an etching mask having a thickness of 0.05 to 0.5.
A chromium (Cr) film or a titanium film (Ti) of about 1 μm, and an etchant made of the chromium film or the titanium film
Gumasuku X-ray absorber (5) as a mask for etching (4)
Is etched.

Next, a method of manufacturing the X-ray exposure mask will be described with reference to a manufacturing process diagram of FIG. As shown in FIG.
Supporting frame (1), underlying protective film (3) on membrane (2),
A resist (EB resist) (6) is applied on a substrate having an X-ray absorber (4) and an etching mask (5). A resist pattern is formed by electron beam exposure and development as shown in FIG. Using the prepared resist pattern as a mask, a flow rate ratio of chlorine-based gas such as Cl ₂ and O ₂ is 10: 1 to 1
1: 2, preferably 4: 1, gas pressure 200-500 mTor
By etching the chromium film of the etching mask (5) using the parallel plate type RIE with the plasma of r, FIG.
A structure having the structure of (c) is manufactured. Finally, using the patterned etching mask (5) as a mask, an X-ray absorber
By etching (4), the structure of FIG. 2D is completed. The etching condition of the X-ray absorber (4) is SF
Flow ratio of ₆ and CHF ₃ 1: 1 to 1: 20, preferably from 1: 9, it is possible to use a gas pressure 5～10MTorr.

Incidentally, tungsten is usually used as the X-ray absorber (4) of the X-ray exposure mask of the present invention. Also, X
The etching mask (4) for etching the line absorber (4)
Using a resist pattern formed by electron beam exposure as a mask, dry etching is performed by chromium etching using a mixed gas plasma of Cl ₂ and O _2.
Can be.

[0015]

EXAMPLE An SiC film having a thickness of 2 μm was formed as a membrane on a Si substrate having a thickness of 2 mm serving as a supporting frame, and a desired opening (2) was formed.
A product provided with 8 mm □) was obtained from HOYA Corporation. Indium tin oxide, tungsten and chromium were deposited on this product by a sputtering method. The sputtering apparatus used was a magnetron sputtering apparatus SPF730H manufactured by Nidec Anelva Co., Ltd. As a sputtering gas, argon was used at a pressure of 15 mTorr. The deposited film thickness is 0.05μ for indium tin oxide.
m, tungsten 0.65 μm, chromium 0.05 μm
Met. Next, as an EB resist, ZEP520 manufactured by Zeon Corporation was spin-coated with a thickness of 0.3 μm. The application condition was 5000 rpm, and after the application, the film was prebaked on a hot plate at 180 ° C. for 3 minutes. EB exposure is JEOL
Exposure was performed using JBX6AIII manufactured by K.K. at a dose of 35 μC / cm ² . The development was performed by tip development for 3 minutes using ZEP-RD manufactured by Zeon Corporation to obtain a resist pattern. The etching of chromium was performed using a Kokusai Electric parallel plate type dry etching apparatus. The flow rates of Cl ₂ and O ₂ gas were 40 SCCM and 160 SCCM, respectively, and the pressure was 200 mTorr.
Chromium was etched at r, RF power 0.37 W / cm ² . 80 to etch 0.05 μm chromium
Seconds needed. Tungsten was etched with SF ₆ and CHF ₃ gas flow rates of ₃ SCCM and 27 SCCM, respectively, a pressure of 7 mTorr, and an RF power of 0.37 W / cm ² . It took 300 seconds to etch 0.65 μm tungsten. It should be noted that indium tin oxide serving as a base protective film was not etched at all during the etching of tungsten. By this tungsten etching, a 0.35 μm tungsten line and space pattern could be formed with good rectangularity.

[0016]

As it is evident from the foregoing description, X-ray exposure mask and its manufacturing method of the present invention, using SF ₆ and CHF ₃ as the etching gas of the X-ray absorber, further etching mask chrome film or a titanium film As a result, it is possible to perform etching with good selectivity and obtain an effect of obtaining a rectangular X-ray absorber pattern.

Further, SiO _{2 is used} as a protective layer of the membrane.
By using the I TO instead, it can also protect the membrane using a gas containing CHF _3. In addition, when ITO is used, since this film has conductivity, there is also an effect that an X-ray absorber pattern can be inspected by an electron beam.

[Brief description of the drawings]

FIG. 1 is a sectional side view of an X-ray exposure mask according to an embodiment of the present invention.

FIG. 2 is a process diagram showing a method for manufacturing an X-ray exposure mask according to one embodiment of the present invention.

FIG. 3 is a cross-sectional side view of a conventional X-ray exposure mask.

FIG. 4 is a process chart showing a conventional method for manufacturing an X-ray exposure mask.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Support frame 2 Membrane 3 Protective film 4 X-ray absorber 5 Etching mask 6 Resist (electron beam photosensitive resist: EB resist) 13 Coated oxide film

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-77017 (JP, A) JP-A-3-257814 (JP, A) JP-A-63-9932 (JP, A) JP-A-62-1987 142323 (JP, A) JP-A-60-132323 (JP, A) JP-A-2-2618 (JP, A) JP-A-3-201529 (JP, A) JP-A-2-94520 (JP, A) JP-A-3-248530 (JP, A) JP-A-3-34311 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/027 G03F 1/16 G03F 7/20 503 G03F 7/20 521

Claims (3)

(57) [Claims] 1. An X-ray exposure mask using tungsten as an X-ray absorber, a chromium film or a titanium film serving as an etching mask when processing tungsten on an upper surface of tungsten, and processing tungsten on a lower surface of tungsten. X-ray exposure mask characterized by having an indium oxide scan's serving as a base protective film due to <br/>. 2. The method of manufacturing an X-ray exposure mask according to claim 1, wherein the tungsten is processed by dry etching using a mixed gas of SF ₆ and CHF ₃ using a chromium film or a titanium film as an etching mask. A method for manufacturing an X-ray exposure mask. 3. The X-ray according to claim 2, wherein the chromium film serving as an etching mask is formed by dry etching using a mixed gas plasma of Cl ₂ and O ₂ using a resist mask formed by electron beam exposure. A method for manufacturing an exposure mask.