JP2003007590A - Stencil mask, its manufacturing method and exposing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stencil mask exhibiting excellent electron beam irradiation characterstics in which a thin film can be deposited easily while controlling stress. SOLUTION: The stencil mask comprises a basic body and a parent material of mask supported by the basic body wherein the parent material of mask comprises a thin film principally comprising carbon and having a through hole pattern passing a charged particle beam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stencil mask used for exposing a charged particle beam such as an electron beam or an ion beam, a method for manufacturing the same, and an exposure method.

[0002]

2. Description of the Related Art In recent years, miniaturization of semiconductor devices has been rapidly progressing. Various exposure techniques have been developed as a manufacturing technique of an element having such a fine pattern. For example,
There are an electron beam exposure method such as electron beam partial batch exposure and electron beam stepper exposure, an ion exposure method, an exposure method using light in the vacuum ultraviolet region, and an exposure method using light in the extreme ultraviolet region.

Of these, as an exposure method using an electron beam, a method of performing equal-magnification exposure using an electron beam is disclosed in Japanese Patent No. 29.
It is proposed in Japanese Patent No. 51947. This method has a feature that the acceleration voltage of the electron beam is 1/20 as compared with the conventional exposure method using an electron beam.

In a stencil mask used for equal-magnification exposure, the processing accuracy of the mask pattern is important. In particular,
The aspect ratio, which is the ratio of the mask film thickness to the mask pattern line width (electron beam transmission hole diameter), becomes a problem. The mask pattern is processed by dry etching, but the aspect ratio is usually about 10. Therefore,
For example, in order to form a pattern having a line width of 100 nm, the film thickness of the mask is limited to about 1 μm.

Therefore, the above-mentioned Japanese Patent No. 2951947 discloses that a stencil mask made of single crystal silicon has a thickness of 0.2 μm to 1.0 μm. However, this patent publication does not describe any method for manufacturing such a stencil mask made of single crystal silicon.

Generally, when single crystal silicon is used as a material of a thin film forming a stencil mask, a substrate is required to support the thin film and maintain the flatness of the mask.
As this substrate, single crystal silicon is used in terms of workability and availability. Since the thin film is finely processed by etching, an SOI (Silico) structure having a structure in which a silicon oxide film is sandwiched between two single crystal silicon substrates is used.
n On Insulator) substrate, a mask pattern is produced by polishing one single crystal silicon substrate to a predetermined film thickness and then patterning. At this time, the silicon oxide film as the intermediate layer of the SOI substrate functions as an etching stopper when processing the mask pattern.

However, with such a method, it is extremely difficult to polish the single crystal silicon substrate to the above-mentioned thin film of 0.2 μm to 1.0 μm. Further, with such a film thickness, there is a problem that a stress is applied to the silicon oxide film in the manufacturing process of the stencil mask to cause cracks in the thinned single crystal silicon substrate.

Therefore, a stress adjusting step is required for the single crystal silicon thin film formed on the silicon oxide film. In such a case, however, there is a problem that the takt time becomes long because the manufacturing steps increase.

[0009]

SUMMARY OF THE INVENTION The present invention has been made under the above circumstances, provides a stencil mask which is easy to be thinned, is capable of controlling stress, and has excellent electron beam irradiation characteristics. The purpose is to do.

Another object of the invention is to provide a method of manufacturing such a stencil mask.

Still another object of the present invention is to provide a charged particle beam exposure method using such a stencil mask.

[0012]

In order to solve the above-mentioned problems, the present invention comprises a substrate and a mask matrix supported by the substrate, wherein the mask matrix is a through hole pattern through which a charged particle beam is transmitted. And a stencil mask comprising a thin film containing carbon as a main component.

According to the present invention as described above, since the mask base is made of the thin film containing carbon as the main component, it is possible to design and control the stress applied to the thin film containing carbon as the main component, and to reduce the resistance. Can be achieved.

The thin film containing carbon as a main component is formed by CVD.
Stencil mask with excellent charged particle beam irradiation characteristics because it can be easily formed into a film, has excellent workability, and can form a pattern with a desired aspect ratio with high accuracy, making it easy to design and control the process. Can be obtained.

In the stencil mask of the present invention, the thin film containing carbon as a main component preferably has a thickness of 0.1 μm or more and 5 μm or less. Film thicknesses within this range were difficult to form with single crystal silicon, but can be easily obtained on silicon oxide with good controllability by a CVD method or the like.

The surface of the thin film containing carbon as a main component is
It is preferably terminated with an electron donating group. By thus forming the electron donating group termination structure on the surface of the thin film, conductivity can be imparted to the surface of the thin film, and as a result, charge-up can be prevented.

Further, the carbon-based thin film can be a diamond thin film. Thus, by forming the mask base with the diamond thin film, it is possible to obtain a stencil mask having extremely excellent irradiation resistance.

In this case, if the diamond thin film is a non-single-crystal diamond thin film, it has an advantage that it can be formed on a wide range of substrates. Particularly, in the case of a polycrystalline diamond thin film, it is extremely excellent in resistance to charged particle irradiation. You can get a stencil mask.

Further, the non-single crystal diamond thin film can be a diamond-like carbon thin film. By using a diamond-like carbon thin film, it is possible to form a film on a wide range of substrates, and because it has excellent workability,
It is possible to obtain a highly accurate stencil mask. In particular,
When the diamond-like carbon thin film doped with impurities is used, it is possible to obtain a stencil mask having excellent resistance to irradiation with charged particles because it has conductivity.

The present invention comprises a step of forming a thin film containing carbon as a main component on a substrate by a plasma CVD method using a source gas containing methane, and a step of patterning the thin film containing carbon as a main component. A method for manufacturing a stencil mask provided is provided.

Further, according to the present invention, nitrogen, boron, sulfur and silicon are formed on a substrate by a plasma CVD method using a source gas containing at least one selected from the group consisting of methane, ammonia and hydrogen sulfide. Provided is a method for manufacturing a stencil mask, which comprises a step of forming a thin film containing carbon as a main component and including at least one selected from the group consisting of: and a step of patterning the thin film containing carbon as a main component.

According to these manufacturing methods, it is possible to easily obtain a stencil mask having excellent charged particle beam irradiation characteristics with high accuracy and without causing cracks or peeling due to stress.

In the above manufacturing method, the patterning of the thin film containing carbon as a main component can be performed by dry etching with an etching gas containing oxygen gas using a resist pattern containing silicon as a mask. Alternatively, it can be performed by dry etching with an etching gas containing oxygen gas, using as a mask a resist in which a compound containing silicon is introduced in a pattern on the surface.

These silicon-containing resist patterns have a high resistance to an etching gas containing oxygen gas. Therefore, the resist film thickness can be reduced and a pattern with a high aspect ratio can be formed. There is an effect that a fine pattern can be accurately formed on the thin film.

Further, the present invention provides a charged particle beam exposure method comprising a step of irradiating the above-mentioned stencil mask with a charged particle beam to shape the charged particle beam into a transfer pattern shape. According to such an exposure method, the resist formed on the sample substrate can be subjected to accurate pattern exposure, and as a result, a pattern such as a semiconductor can be manufactured with a high yield.

[0026]

DETAILED DESCRIPTION OF THE INVENTION A stencil mask according to one embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a stencil mask according to one embodiment of the present invention. In FIG. 1, a stencil mask 1 is formed by forming a mask matrix 3 made of a thin film containing carbon as a main component, which has a predetermined transparent hole pattern on a single crystal silicon wafer 2 having openings formed therein. Has been done.

For the supporting substrate, a semiconductor material such as gallium-arsenic or indium-phosphorus can be used in addition to single crystal silicon.

As the thin film forming the mask base 3, a diamond thin film or a diamond-like carbon thin film can be used. As the diamond thin film, a non-single crystal diamond thin film, particularly a polycrystalline diamond thin film is desirable. The diamond-like carbon thin film is preferably doped with impurities, for example, at least one selected from the group consisting of nitrogen, boron, sulfur and silicon.

The surface of the thin film containing carbon as a main component is
It is preferably terminated with an electron donating group. Examples of the electron donating group include an H group and an OR group (R is H or an alkyl group).

The thickness of the thin film containing carbon as the main component is 0.1
It is desirable that the thickness is not less than μm and not more than 5 μm. If the film thickness is too thin, the non-single-crystal silicon thin film 3 may melt if the current value is increased to increase the throughput, and if it is too thick, the mask pattern processing accuracy cannot be increased. .

In the stencil mask according to this embodiment configured as described above, a thin film containing carbon as a main component is used as the mask base instead of the conventionally used single crystal silicon thin film. Since it is excellent in electron beam irradiation such as irradiation resistance and conductivity and can form a thin film having a thin film thickness, it is possible to form a pattern having a desired aspect ratio with high accuracy.

Next, the manufacturing process of the stencil mask described above will be described with reference to FIGS.
First, as shown in FIG. 2, a thin film 12 containing carbon as a main component is formed on a single crystal silicon substrate 11 by a plasma CVD method or the like.

Next, as shown in FIG. 3, the thin film 12 containing carbon as a main component is patterned to form a mask matrix 13 having a predetermined through hole pattern. This through hole pattern forming process includes a step of forming a resist pattern on the thin film 12 containing carbon as a main component, a step of dry etching the thin film 12 containing carbon as a main component using the resist pattern as a mask, The process is sequentially performed through a process called a peeling process.

When the thin film 12 containing carbon as a main component is dry-etched, if the resist has insufficient etching resistance, an inorganic compound such as a silicon oxide film, a silicon nitride film or a silicon carbide film, chromium, Metals such as tungsten, tantalum, titanium, nickel, and aluminum, alloys containing these metals, or metal compounds of these metals or alloys with oxygen, nitrogen, carbon, or the like can be used as an etching mask. These etching masks can be formed by various thin film forming methods. For example, there are forming methods such as a sputtering method, a CVD method, and a vapor deposition method.

Dry etching can be performed using oxygen as an etching gas. It is also possible to add sulfur dioxide to oxygen. By adding sulfur dioxide to oxygen, the effect of reducing the edge roughness of the pattern can be obtained. The amount of sulfur dioxide added is preferably about 5 to 30%.

As a dry etching apparatus, R
Examples of the dry etching apparatus include discharge methods such as IE, magnetron RIE, ECR, ICP, microwave, helicon wave, and NLD.

After that, as shown in FIG. 4, an opening 14 is formed in the single crystal silicon substrate 11 to complete the stencil mask. In this step, dry etching, wet etching, ultrasonic processing, sand blast, etc. can be preferably used. Either the patterning process of the thin film 12 containing carbon as a main component or the process of forming the opening in the single crystal silicon substrate 11 may be performed first.

Next, another example of the stencil mask manufacturing process will be described with reference to FIGS. First, as shown in FIG. 5, on the single crystal silicon substrate 21,
A thin film 22 containing carbon as a main component by the plasma CVD method.
After forming, the opening 23 is formed in the single crystal silicon substrate 21.

Next, as shown in FIG. 6, a resist film 24 is formed on the thin film 22 containing carbon as a main component. In this case, as the resist, a silicon-containing resist 24 (FIG. 6) or a resist 31 (FIG. 9) in which a silicon compound is introduced into the surface in a pattern can be used.

Examples of the silicon-containing resist include an alkali-soluble silicone polymer containing a naphthoquinonediazide type photosensitive material. As such, there is FH-SP (trade name, manufactured by Fuji Film Arch Co., Ltd.).

The silicon-containing resist has a g-line (wavelength 43
6 nm) or i-line (wavelength 365 nm) to form a pattern, and then developed using TMAH which is a general-purpose developing solution for resist to obtain a resist pattern 25 as shown in FIG.

The resist in which the silicon compound is introduced in a pattern on the surface can be obtained by the following method. (1) Method of selectively silylating exposed areas (negative type) A resist containing poly (p-methoxystyrene) and an onium salt is irradiated with light in a pattern to generate an acid in the irradiated areas. Next, when it is brought into contact with a vapor containing silicon, cationic polymerization proceeds only in the exposed portion, and as shown in FIG. 9, it is composed of a portion 32 into which a silicon compound has been introduced and a portion 33 into which a silicon compound has not been introduced. A resist 31 having a silicon compound introduced in a pattern is obtained.

(2) Method for selectively silylating unexposed area (positive type) A resist containing azide and cyclized rubber is irradiated with light in a pattern to decompose the azide in the irradiated area. Next, SiCl
_When contacted with ₄ vapor, the azide in the unexposed portion forms a complex and traps SiCl ₄ , and as shown in FIG. 9, the portion 32 into which the silicon compound has been introduced and the portion into which the silicon compound has not been introduced. A resist 31 composed of 33 and having a silicon compound introduced in a pattern is obtained.

When the resist 31 formed by the above method and having a silicon compound introduced in a pattern is subjected to reactive ion etching, a portion not containing silicon is removed, and as shown in FIG. The pattern 25 is formed.

When the thin film 22 containing carbon as a main component is dry-etched and the resist has insufficient etching resistance, an inorganic compound such as a silicon oxide film, a silicon nitride film or a silicon carbide film, chromium, Metals such as tungsten, tantalum, titanium, nickel, and aluminum, alloys containing these metals, or metal compounds of these metals or alloys with oxygen, nitrogen, carbon, or the like can be used as an etching mask. These etching masks can be formed by various thin film forming methods. For example, there are forming methods such as a sputtering method, a CVD method, and a vapor deposition method.

Then, using the resist pattern 25 as a mask, the thin film 22 containing carbon as a main component is dry-etched to form a mask matrix 26 having a predetermined through-hole pattern as shown in FIG.

Dry etching can be performed using oxygen as an etching gas. It is also possible to add sulfur dioxide to oxygen. By adding sulfur dioxide to oxygen, the effect of reducing the edge roughness of the pattern can be obtained. The amount of sulfur dioxide added is preferably about 5 to 30%.

As a dry etching apparatus, R
Examples of the dry etching apparatus include discharge methods such as IE, magnetron RIE, ECR, ICP, microwave, helicon wave, and NLD.

Finally, the resist pattern 25 is peeled off to obtain a stencil mask as shown in FIG.

[0051]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described in detail below with reference to the drawings.

Example 1 With reference to FIGS. 5 to 8, a process of manufacturing a stencil mask according to an example of the present invention will be described. As shown in FIG. 5, on a single crystal silicon substrate 21 having a thickness of 525 μm,
The diamond-like carbon thin film 22 was formed using a parallel plate type plasma CVD apparatus.

The conditions of plasma CVD are as follows. Source gas: Methane (20 sccm) Dope gas: Nitrogen (1-50%) Or ammonia (1-50%) Reaction pressure: 0.03 Torr Vdc: 0-1500V Film thickness: 500 nm.

Then, the single crystal silicon substrate 11 is anisotropically etched along the plane orientation by being contained in an etching solution of a KOH aqueous solution heated to about 90 ° C. and using a predetermined protective film (not shown) as a mask. Then, the opening 23 was formed. Then, the protective film was removed by etching.

Next, as shown in FIG. 6, a silicon-containing resist 24 was applied on the diamond-like carbon thin film 22 to a thickness of 0.3 μm. FH-SP (trade name, manufactured by Fuji Film Arch Co., Ltd.) was used as the silicon-containing resist.

Thereafter, the silicon-containing resist 24 was exposed in a pattern by using g rays, and then a dedicated developer FHD-5 (trade name, manufactured by Fuji Film Arch Co., Ltd.) was used.
Was used to form a resist pattern 25.

Next, using the resist pattern 25 as a mask, a plasma etching apparatus is used, and oxygen is used as an etching gas to dry-etch the diamond-like carbon thin film 22, and as shown in FIG. Was formed.

Finally, the resist pattern 25 was peeled off using a phenol-based peeling solution to complete a stencil mask.

In the stencil mask manufactured as described above, since the mask base 26 has a very thin film thickness of 500 nm and has a low stress, no peeling or cracking occurs, and the resistance is low, so that a separate metal is used. There is no need to provide a membrane. Further, the obtained stencil mask had high pattern accuracy and was excellent in charged particle beam irradiation characteristics.

Example 2 In the process shown in FIG. 6 of Example 1, a resist 24 containing poly (p-methoxystyrene) and an onium salt was formed to a thickness of 0.3 μm. Then, the resist 24
Then, light was irradiated in a pattern form to generate an acid in the irradiated portion. Next, a silicon-containing vapor (DMSDEA (dimethylsilyldimethylamine) is brought into contact to cause cationic polymerization to proceed only in the exposed portion, and as shown in FIG. 9, the portion 32 into which the silicon compound has been introduced and the silicon compound have been introduced. A resist 31 in which a silicon compound was introduced in a pattern was formed, which was composed of a portion 33 which was not formed.

Then, when the resist 31 is subjected to reactive ion etching using oxygen as an etching gas,
The portion 33 into which the silicon compound is not introduced is selectively removed, and as shown in FIG.
Was formed.

After that, through the same steps as in Example 1, a stencil mask as shown in FIG. 1 was obtained.

Also in this example, the same effect as in Example 1 was obtained.

[0064]

As described above in detail, according to the present invention, since the mask base is made of the thin film containing carbon as a main component, it is possible to easily form a film by CVD or the like, and the processing process is performed. Can be easily designed and controlled, has excellent workability, can form a pattern having a desired aspect ratio with high accuracy, and can obtain a stencil mask having excellent charged particle beam irradiation characteristics.

Further, according to the manufacturing method of the present invention, a stencil mask excellent in charged particle beam irradiation characteristics can be obtained with high accuracy.
It can be easily obtained without causing cracks or peeling due to stress.

Further, according to the exposure method of the present invention, it is possible to perform pattern exposure with high precision on the resist formed on the sample substrate, and as a result, it is possible to manufacture a pattern such as a semiconductor with a high yield. .

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a stencil mask according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a manufacturing process of a stencil mask according to one embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a manufacturing process of a stencil mask according to one embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a manufacturing process of a stencil mask according to one embodiment of the present invention.

FIG. 5 is a cross-sectional view showing another example of a stencil mask manufacturing process according to one embodiment of the present invention.

FIG. 6 is a cross-sectional view showing another example of a stencil mask manufacturing process according to an aspect of the present invention.

FIG. 7 is a cross-sectional view showing another example of a stencil mask manufacturing process according to one embodiment of the present invention.

FIG. 8 is a cross-sectional view showing another example of a stencil mask manufacturing process according to an aspect of the present invention.

FIG. 9 is a cross-sectional view showing still another example of the stencil mask manufacturing process according to one embodiment of the present invention.

[Explanation of symbols]

1 ... Stencil mask 2,11,21 ... Single crystal silicon substrate 3, 13, 26 ... Mask mother 12, 22 ... Carbon-based thin film 14, 23 ... Aperture 24 ... Resist 25 ... Resist pattern

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akira Tamura             1-5-1 Taito, Taito-ku, Tokyo Toppan stamp             Imprint Co., Ltd. F-term (reference) 2H095 BA08 BC05 BC08                 4K030 AA01 AA10 AA13 BA28 BB03                       CA04 DA05 FA01 LA11                 5F056 AA22 FA05

Claims (15)

[Claims] 1. A base body and a mask base body supported by the base body, wherein the mask base body has a transparent hole pattern through which a charged particle beam is transmitted, and is composed of a thin film containing carbon as a main component. Characteristic stencil mask. 2. The carbon-based thin film has a thickness of 0.1 μm.
The stencil mask according to claim 1, having a thickness of not less than m and not more than 5 μm. 3. The stencil mask according to claim 1, wherein the surface of the thin film containing carbon as a main component is terminated with an electron donating group. 4. The stencil mask according to claim 1, wherein the carbon-based thin film is a diamond thin film. 5. The stencil mask according to claim 1, wherein the carbon-based thin film is a non-single crystal diamond thin film. 6. The stencil mask according to claim 5, wherein the non-single crystal diamond thin film is a polycrystalline diamond thin film. 7. The non-single crystal diamond thin film is a diamond-like carbon thin film.
Stencil mask described in. 8. The stencil mask according to claim 7, wherein the non-single-crystal diamond thin film is a diamond-like carbon thin film doped with impurities. 9. The stencil mask according to claim 8, wherein the impurity is at least one selected from the group consisting of nitrogen, boron, sulfur and silicon. 10. A step of forming a thin film containing carbon as a main component on a substrate by plasma CVD using a source gas containing methane, and a step of patterning the thin film containing carbon as a main component. Manufacturing method of stencil mask. 11. A material selected from the group consisting of nitrogen, boron, sulfur and silicon by plasma CVD using a source gas containing at least one selected from the group consisting of methane, ammonia and hydrogen sulfide on a substrate. A method of manufacturing a stencil mask, comprising: a step of forming a thin film containing carbon as a main component containing at least one selected from the above; and a step of patterning the thin film containing carbon as a main component. 12. The patterning of the thin film containing carbon as a main component is performed by dry etching with an etching gas containing oxygen gas using a resist pattern containing silicon as a mask. Alternatively, the method for manufacturing a stencil mask according to item 11. 13. The patterning of the thin film containing carbon as a main component is performed by dry etching with an etching gas containing oxygen gas using a resist having a compound containing silicon on the surface introduced in a pattern as a mask. The method for manufacturing a stencil mask according to claim 10 or 11, characterized in that. 14. The method of manufacturing a stencil mask according to claim 13, wherein the etching gas further contains sulfur dioxide. 15. A charged particle beam exposure method comprising a step of irradiating the stencil mask according to claim 1 with a charged particle beam to shape the charged particle beam into a shape of a transfer pattern.