JPH08222508A - Pattern formation method of photosensitive composition - Google Patents

Abstract

PURPOSE: To provide a new pattern formation method in which a swelling and a side reaction are not generated, in which a development waste liquid is not generated and in which a batch treatment can be executed. CONSTITUTION: The pattern formation method of a photosensitive resin composition contains a process wherein a photosensitive composition whose molecular weight is increased substantially by an exposure or which generates a cross- linking reaction is coated on a substrate, a pattern is exposed, and an unexposed part is removed by using a supercritical fluid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for patterning a photosensitive composition which is sensitive to radiation such as near-ultraviolet light, far-ultraviolet light, excimer laser light, electron beam, X-ray and ion beam. In particular, the present invention is suitable for a photoresist for microfabrication because it has no notching due to swelling and scum caused by side reactions such as alkali.

The photoresist composition according to the present invention is applied to a substrate such as a semiconductor wafer, glass, ceramics or metal by spin coating method or roller coating method at 0.5.
It is applied to a thickness of ˜3 μm. After that, it is heated and dried, a circuit pattern or the like is baked with an ultraviolet ray or the like through an exposure mask, and is processed using a supercritical fluid, whereby an image can be formed on the substrate.

Further, the pattern can be processed on the substrate by etching using this image as a mask. Typical fields of application include semiconductor manufacturing processes such as ICs, circuit boards such as liquid crystal and thermal heads, and other photofabrication processes.

An image obtained by applying the above photoresist composition on an aluminum plate having a roughened surface, exposing it to a pattern and treating it with a supercritical fluid can also be used as a printing plate for printing. .

[0005]

2. Description of the Related Art Photosensitive compositions are classified into a positive type which dissolves and removes exposed areas and a negative type which dissolves and removes unexposed areas. The negative photosensitive composition represented by cyclized isoprene rubber has a reduced solubility in an organic solvent due to an increase in the molecular weight of the exposed portion or crosslinking, and as a result, only the unexposed portion is dissolved and removed to give a negative image. However, the rubber-based resist is developed by an organic solvent and has a problem that it has a large load on the environment and that it swells during development to cause pattern deformation after drying and deterioration of resolution. Similarly, a chemically amplified negative resist that uses an azide-based cross-linking agent, a negative resist that uses a photoacid generator and methylolmelamine together, or a negative resist that consists of a combination of a photoradical generator and a polymerizable group. Also, when notching due to swelling at the time of development or when an alkaline developing solution is used, scum caused by side reactions or the like becomes a problem, and improvement has been desired.

On the other hand, as a positive photoresist composition, an alkali-soluble resin and a naphthoquinonediazide compound as a photosensitive material are generally known. For example, "Novolak type phenolic resin / naphthoquinone diazide substituted compound" is USP 3,666,473 and USP 4,17.
3, 470 and the like. Also, the most typical composition is "cresol-formaldehyde novolac resin / trihydroxybenzophenone-1,
An example of "2-naphthoquinone sulfonate" is Thompson "Introduction toe microlithography" (LF Thompson "Introdu").
action to Microlithograph
y ”(ACS Publishing, No. 219, p112-12)
It is described in 1).

Further, deep such as KrF excimer laser
As UV lithography, a method of forming a pattern by changing the alkali solubility of the exposed area by pending an acid-decomposable group on an alkali-soluble resin and using a photo-acid generator in combination, an alkali-soluble resin, and inhibition of acid-decomposable dissolution A method of changing the alkali solubility of the exposed area to form a pattern by using an agent and a photo-acid generator in combination, an acid-decomposable dissolution inhibiting agent in which an acid-decomposable group is partially pendant to an alkali-soluble resin, and Various compositions have been proposed, such as a method of forming a pattern by changing the alkali solubility of an exposed area using a photo-acid generator. However, all of the above-mentioned photosensitive compositions are developed by an aqueous alkaline solution, so that side reactions due to alkali give rise to problems such as scum, and it is difficult to control developer concentration, temperature, time, etc. The current situation is that it cannot be done. Further, in the conventional development, single-wafer processing is generally used, and there is a problem in throughput.

[0008]

Therefore, the object of the present invention is to (1) obtain a smooth pattern without causing swelling and side reactions, (2) not generate developing waste liquid, and (3) enable batch processing. What is to be done is to show a new pattern forming method that enables the above three.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies with the above characteristics in mind, and as a result, by applying a process of treating a pattern-exposed photosensitive composition with a supercritical fluid, It has been found that the object is achieved, and the present invention has been completed based on this finding.

That is, the present invention includes the following eight inventions. Invention 1 A photosensitive composition that causes a substantial increase in molecular weight or a crosslinking reaction upon exposure is applied (1) to a substrate, (2) to perform pattern exposure, and (3) to unexpose by immersing in a supercritical fluid. A method of forming a pattern of a photosensitive composition, which comprises a process of removing a portion.

Invention 2 A photosensitive composition whose molecular weight is substantially reduced by exposure is applied to (1) a substrate, (2) pattern exposure is performed, and (3) the exposed portion is exposed by dipping in a supercritical fluid. A method of forming a pattern of a photosensitive composition, which comprises a removing process.

Invention 3 A method of (1) applying a photosensitive composition on a substrate such that the polarity of an exposed portion is substantially lowered by exposure, (2) performing pattern exposure, and (3) immersing in a supercritical fluid. A method of forming a pattern of a photosensitive composition, comprising the step of removing an exposed portion by means of

Invention 4 A photosensitive composition which makes the polarity of exposed areas substantially higher upon exposure is (1) coated on a substrate (2) subjected to pattern exposure (3) immersed in a supercritical fluid The method for forming a pattern of a photosensitive composition, comprising:

Invention 5 The supercritical fluid used in the above Inventions 1 to 4 is carbon dioxide, methane, ethylene, ethane, propane, butane, ammonia, methanol, ethanol, water, toluene, benzene, pentane, nitrous oxide, chlorotrifluoro. A method for forming a pattern of a photosensitive composition, which is selected from methane, trifluoromethane, chlorodifluoromethane, and hexane.

Invention 6 A method for forming a pattern of a photosensitive composition, wherein the supercritical fluid used in the above Inventions 1 to 4 is carbon dioxide, and the treatment temperature is 40 ° C. or higher and the pressure is 100 atm or higher.

Invention 7 A method for forming a pattern of a photosensitive composition according to any one of Inventions 1 to 6, wherein a solvent having a solubility parameter of 8.5 or more is added to the supercritical fluid as a dissolution promoting aid.

Invention 8 In the above Invention 7, a pattern of a photosensitive composition, characterized in that a solvent selected from methanol, ethanol, propanol, acetone, tetrahydrofuran, acetonitrile, 1,4-dioxane and the like is added as a dissolution accelerating aid. Forming method.

A supercritical fluid is a temperature above the critical point of gas-liquid,
A high-density fluid compressed by pressure. It is known that carbon dioxide enters a critical state at a critical temperature (Tc) of 31.1 ° C. and a critical pressure (Pc) of 73 atm. These supercritical fluids have both a gas property (high miscibility and diffusivity) and a liquid property (high solubility). It is said that the supercritical fluid of carbon dioxide has low polarity and is comparable to hexane, and its solubility is similar to this. However, this solubility changes with pressure.

This supercritical fluid has been applied to various separation and purification processes such as treatment of crude oil, desolvation from pharmaceuticals, decaffeination of coffee beans, extraction of extracts from hops. Also applicable to polymer compounds is, for example, Val Kruk.
onis "Processing of Polymer"
rs with Supercritical Flu
ids ”Polymer News Vol. 11
p. 7-16 (1985).

However, the above document does not disclose or suggest that an image in accordance with an exposure pattern can be obtained by applying a supercritical fluid to the photosensitive composition of the present application and developing the composition.

Further, it has been found that applying a supercritical fluid to the pattern forming process has the following advantages. (1) An inexpensive gas such as carbon dioxide can be used,
No waste liquid is generated. (2) The pattern was smooth without swelling, which was a problem in the negative system. (3) No side reaction, which has been a problem with alkaline developers, occurs and scum is not seen. (4) Batch processing is possible in the pressurized container, which is effective in improving throughput.

The supercritical fluid used in the present invention is carbon dioxide, methane, ethylene, ethane, propane, butane, ammonia, methanol, ethanol, water, toluene, benzene, pentane, nitrous oxide, chlorotrifluoromethane, trifluoro. It can be selected from methane, chlorodifluoromethane, hexane, but carbon dioxide is preferred.

When carbon dioxide is used as a supercritical fluid, the temperature during treatment is preferably 40 ° C. or higher and the pressure is 100 atm or higher, more preferably the temperature is 50 ° C. or higher and the pressure is 200 atm or higher. Is preferred.

If necessary, a solvent having a solubility parameter of 8.5 or more can be added as a dissolution aid.
Examples of these solvents include, but are not limited to, methanol, ethanol, propanol, acetone, tetrahydrofuran, acetonitrile, and 1,4-dioxane.

The photosensitive composition used in the present invention is not particularly limited as long as it has different solubilities in the exposed portion and the unexposed portion with respect to the supercritical fluid, and is not particularly limited. Examples of the photosensitive composition that increases or causes a crosslinking reaction include negative resist "SC100" manufactured by Fuji Hunt Electronics Technology Co., Ltd. Also, a chemically amplified negative resist using an azide-based cross-linking agent, a negative resist using a photo-acid generator in combination with methylolmelamine, and a combination of a photo-radical generator and a monomer or polymer having a polymerizable ethylene-based double bond. A negative resist, an electron beam cross-linking resist, an X-ray negative resist, and the like.

(2) As a photosensitive composition whose molecular weight is substantially reduced by exposure to light, a positive resist using polyphthalaldehyde or a combination of a binder having an acid decomposable group in the polymer main chain and a photoacid generator is used. And positive resists.

(3) Examples of the photosensitive composition in which the polarity of the exposed area is substantially lowered by exposure include a carboxylic acid-containing composition which causes photodecarboxylation.

(4) As a photosensitive composition which makes the exposed portion substantially higher in polarity upon exposure, a resist composition containing naphthoquinonediazide or the like, a resin containing t-butyl ester, t-butyloxycarbonyl, or an acetal. , A ketal, a silyl ether group and other acid-decomposable groups are pendant, and a two-component chemical amplification type resist composition and a resin for generating a polar group in the exposed area by using a photo-acid generator such as onium salt or disulfone in combination. Examples thereof include a three-component chemically amplified resist composition comprising an acid-decomposable dissolution inhibitor and a photo-acid generator, and a combination system thereof.

Examples of the present invention will be shown below, but the present invention is not limited thereto.

[0030]

【Example】

Example 1 A negative resist "SC100" manufactured by Fuji Hunt Electronics Technology Co., Ltd. was applied onto a silicon wafer using a spinner to obtain a resist film of 1 μm. This resist film was irradiated with broadband light through a mask to perform pattern exposure.

The wafer was placed in a stirring autoclave and the container was kept at 60 ° C. Introduce carbon dioxide into this container 4
It was kept at 00 atm. The extract was introduced into the separation container from the autoclave via the pressure reducing valve. During the extraction, the introduction of carbon dioxide was continued to maintain the pressure in the autoclave.

After the completion of the treatment, the wafer was taken out and the resist pattern was observed with a scanning electron microscope to evaluate the resist. As a result, notching and scum due to the swelling of the pattern were not observed, and a smooth shape was maintained.

Example 2 A silicon wafer subjected to pattern exposure in the same manner was placed in a stirring autoclave and the container was kept at 60 ° C. A wafer was treated in the same manner as in Example 1 by adding about 5% of methanol to the capacity of the autoclave.

After the completion of the treatment, the wafer was taken out and the resist pattern was observed with a scanning electron microscope to evaluate the resist. As a result, notching and scum due to the swelling of the pattern were not observed, and a smooth shape was maintained. Further, the sensitivity was improved by about 20% as compared with Example 1.

Example 3 When butane was used instead of carbon dioxide in Example 1 and the same treatment as in Example 1 was carried out, the same negative pattern could be obtained.

Comparative Example A silicon wafer which had been subjected to pattern exposure in the same manner as in Example 1 was developed using a developer "WNRD" manufactured by Fuji Hunt Electronics Technology Co., Ltd. and rinsed with butyl acetate. When the wafer after development was observed with a scanning electron microscope, notching due to swelling of the pattern was observed,
Furthermore, scum was generated between the fine patterns.

Claims (8)

[Claims] 1. A photosensitive composition, which causes a substantial increase in molecular weight or a crosslinking reaction upon exposure, is (1) coated on a substrate, (2) subjected to pattern exposure, and (3) unexposed using a supercritical fluid. A method of forming a pattern of a photosensitive composition, which comprises a process of removing a portion. 2. A process of (1) applying a photosensitive composition whose molecular weight is substantially reduced by exposure onto a substrate, (2) performing pattern exposure, and (3) removing an exposed portion using a supercritical fluid. A method for forming a pattern of a photosensitive composition, which comprises: 3. A photosensitive composition in which the polarity of an exposed portion is substantially lowered by exposure is applied (1) onto a substrate, (2) pattern exposure is performed, and (3) exposure is performed using a supercritical fluid. A method of forming a pattern of a photosensitive composition, which comprises a process of removing a portion. 4. A photosensitive composition in which the polarity of the exposed portion is substantially increased by exposure is applied to (1) a substrate, (2) pattern exposure is performed, and (3) using a supercritical fluid. A method of forming a pattern of a photosensitive composition, which comprises a process of removing an exposed portion. 5. The supercritical fluid used in claims 1 to 4 is carbon dioxide, methane, ethylene, ethane, propane,
It is characterized by being selected from butane, ammonia, methanol, ethanol, water, toluene, benzene, pentane, nitrous oxide, chlorotrifluoromethane, trifluoromethane, chlorodifluoromethane, and hexane. 6. The supercritical fluid used in any one of claims 1 to 4 is carbon dioxide, and the treatment temperature is 40 ° C. or higher and the pressure is 100 atm or higher. 7. The method according to any one of claims 1 to 6, wherein a solvent having a solubility parameter of 8.5 or more is added to the supercritical fluid as a dissolution promoting aid. 8. The method according to claim 7, wherein a solvent selected from methanol, ethanol, propanol, acetone, tetrahydrofuran, acetonitrile, 1,4-dioxane and the like is added as a dissolution promoting agent.