JPH04134347A - Pattern forming material - Google Patents

Abstract

PURPOSE:To enable microfabrication of a pattern by using a specified compound to be allowed to produce an acid by exposure to radiation. CONSTITUTION:the pattern forming composition to be used comprises an alkali- soluble polymer compound, a compound capable of restraining solubility of this polymer, a compound acting as a cross-linking agent, and the compound to be allowed to produce an acid by exposure to radiation represented by formula I in R1 is a univalent oxim residue; R3 is an n-valent oxim residue; R2 is an m-valent alkyl or aryl group; R4 is a univalent alkyl or aryl; and X is SO2 or CO, thus permitting sensitivity to radiation to be enhanced and a micropattern to be fabricated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resist used to form highly accurate fine patterns.

[Prior Art] Patterning for microfabrication of semiconductor elements and the like is performed by photolithography. In this case, a resist that is sensitive to actinic rays such as radiation is used. Conventionally, as such materials, materials that decompose when irradiated with radiation, or compounds that harden when irradiated with radiation have been used as resists.

However, these compounds undergo only a sequential reaction, and because they react with irradiated energy, their efficiency is extremely low. As a result, no significant improvement in sensitivity can be expected.

In recent years, in order to solve these problems, resists based on the idea of a chemical amplification mechanism have been studied.

This is a method that uses an acid generated by light irradiation as a catalyst to accelerate the reaction thermally rather than by light. With this method, extremely high sensitivity can be achieved because the amount of light irradiation is sufficient to generate a catalytic amount of acid.

On the other hand, the properties required of resist materials are becoming more sophisticated, and it is not possible to satisfy all the properties by simply forming a resist with a single polymer compound. Therefore, the idea of a multi-component resist that uses several materials in combination to share each characteristic has been proposed. As a resist that takes these two ideas into consideration, for example, Polymer Engine
ring 5science volume 26, 1101
A resist consisting of a novolac resin, a melamine resin, and an acid generator described in JP-A-1-10640, and a resist consisting of a novolac resin, an acetal compound, and an acid generator described in JP-A-1-10640 have been proposed. .

As the acid generator used in the above-mentioned resist composition, an onium salt-based compound is usually used from the viewpoint of reaction efficiency. However, with onium salts, the reaction starts efficiently with a small amount of light irradiation, but if excess light is irradiated even after ψ, side reactions may occur, and positive resists may become negative, or Negative resists have problems such as fogging in unexposed areas and a reduction in resolution.

[Problems to be Solved by the Invention] The present invention has been made to solve the problems of the prior art as described above. The object of the present invention is to provide a resist material in which only the exposed portion remains faithfully (in the case of a type resist) or in which only the exposed portion remains faithfully (in the case of a negative resist), resulting in a good pattern formation.

[Means for Solving the Problems] As a result of repeated research, the present inventors have found that (a) an alkali-soluble polymer compound, (b) a compound that can act as a solubility inhibitor for the alkali-soluble polymer compound, Alternatively, in a pattern forming material comprising a compound (c) that acts as a crosslinking group for the alkali-soluble polymeric compound moiety and a compound that generates an acid upon irradiation with radiation, (c) is -Noshiro (1
) % Formula %) (In the formula, R1 represents a monovalent oxime residue, R3 represents an n-valent oxime residue, R2 represents an m-valent alkyl group or aryl group, R4 represents a monovalent alkyl group, X represents an aryl group
indicates either SO2 or CO. ) has been found to be useful as a material for pattern formation.

[Function] That is, by irradiating the composition of the present invention with radiation, the compound (c) generates an acid in the exposed area, and this acid acts as a solubility inhibitor for the alkali-soluble polymer compound. It decomposes the compound containing the alkali-soluble polymer, or it acts on the compound that acts as a crosslinking group for the plucari-soluble polymer compound, causing only a crosslinking reaction with the alkali-soluble polymer compound. At this time, the compound (c) does not produce compounds other than acids that inhibit the above reaction.

[Example] The alkali-soluble polymer compound that can be used in the present invention needs to have a structure with excellent dry etching resistance, and materials that meet this purpose include, for example, phenol novolak resin, cresol novolak resin, and naphthol. Examples include phenol-formaldehyde resins such as novolac resins, polyvinylphenol resins, and copolymers of vinylphenol and acrylic or styrene monomers.

The average molecular weight of these is preferably about 2,000 to 50,000. When it is less than 2000, uniform coating properties cannot be obtained and dry etching resistance is also reduced. Also, 50
If it is more than 000, the solubility of the exposed area during development decreases, resulting in the occurrence of development residue.

Compounds that can serve as solubility inhibitors for the alkali-soluble polymer compound used in the present invention include acid ester compounds obtained by reacting polyvalent carboxylic acid halide or polyvalent sulfonic acid halide with alcohol or phenols; An alkoxycarbonate compound obtained by reacting a phenol with a dialkoxycarbonate anhydride is selected. Examples of acid chlorides include isophthalic acid dichloride, terephthalic acid dichloride, benzenetricarboxylic acid chloride, benzophenone dicarboxylic acid chloride, diphenyl ether dicarboxylic acid chloride, polyphenylmethane dicarboxylic acid chloride, naphthalene dicarboxylic acid chloride, benzene disulfonic acid chloride, and benzene. Examples include trisulfonic acid chloride, diphenyl ether disulfonic acid chloride, polyphenylmethane disulfonic acid chloride, hexamethylene dicarboxylic acid chloride, cyclohexyldicarboxylic acid chloride, butanetetracarboxylic acid dichloride, and the like.

Further, examples of the alcohol include t-butyl alcohol, t-amyl alcohol hexanol, and the like. Furthermore, phenols such as phenol, cresol, and anisole can be mentioned.

Examples of polyhydric phenols include bisphenol A, bisphenol F, bisphenol S, phenol novolac, cresol novolac, resorcinol, pyrogallol, etc., and as dialkoxycarbonate acid anhydride, di-monobutoxycarbonate Examples include acid anhydrides, di-t-amylcarbonate acid anhydrides, and the like.

Examples of the compound that acts as a crosslinking group for the alkali-soluble polymer compound include melamine resin, resol resin, and epoxy resin.

The compound represented by the general formula (I) used in the present invention can be synthesized by reacting a polyacid halide or a monoacid halide with a monooxime compound or a polyoxime compound. Examples of polyhydric acid halides can be selected from those listed above. Examples of monoacid halides include methanesulfonic acid chloride, ethanesulfonic acid chloride, trifluorosulfonic acid chloride, P-toluenesulfonic acid chloride, and trifluoroacetic acid chloride. Examples of oxime compounds include acetoxime, cyclohexanone oxime, acetophenone oxime, glyoxime, quinone oxime, and cyclohexane dioxime.

In the present invention, the three components described above are compound 9 of (a).
It is appropriate to select within the range of 0 to 40%, 10 to 60% of the compound (b), and 0.05 to 20% of the compound (c). When the amount of the compound (a) is 90% or more, the amount of the component (b) decreases, making patterning by exposure difficult.
When it is less than 40%, the content of alkali-soluble polymer compounds decreases, resulting in a decrease in dry etching resistance. In addition, if the component (c) is 0.05% or less,
A good pattern cannot be formed, and if it exceeds 20%, residue may occur during development or compatibility of the three components may not be obtained.

The composition of the present invention is prepared as a solution and used by coating it using a spin coater or the like, and any solvent can be used as long as it does not react with the three components mentioned above. For example, cellosolve acetate, dimethyl glyme, dimethyl glyme, cyclohexanone, cyclopentanone, methyl isobutyl ketone, isoamyl acetate, dioxane, etc. are common.

As a method of carrying out the present invention, a solution containing a pattern forming material is applied to a substrate such as a silicone wafer, heated to remove the solvent, and then irradiated with radiation through a mask having a predetermined pattern (electronic (In the case of lines, drawing is performed) Then, heating is performed at 60 to 150°C, and then development is performed. As the developer at this time, an aqueous solution of ammonia, triethylamine, dimethylethanol, tetramethylammonium hydroxide, sodium hydroxide, sodium carbonate, etc. can be used.

The pattern forming material of the present invention is composed of three components as described above, and an adhesion improver (for example, aminosilazane, aminoalkoxysilane, alkylalkoxysilane, Silane, metal chelate, etc.) and other compounds suitable for the purpose can be added as necessary.

The pattern forming material of the present invention can be used as a resist for microfabrication of semiconductor elements, printed wiring boards, etc. that require micropatterning.

The present invention will be described below with reference to specific examples, but the present invention is not limited thereto.

Example 1 0.1 mole of cyclohexanedioxime and 0.1 mole of pyridine.
2 moles of dried tetrahydrofuran and 100 moles of dried tetrahydrofuran were placed in a flask, and while stirring, 0.18 moles of methanesulfonic acid chloride was added at room temperature. After stirring for 4 hours, tetrahydrofuran was distilled off and the product was poured into water. The reaction product was extracted with ethyl ether, and the resulting crude product was collected by distillation to obtain the desired acid generator.

Dissolve 7 g of cresol novolak resin (Mn = 6000), 3 g of terephthalic acid t-butyl ester, and 0.5 g of the acid generator obtained above in 25 g of cyclohexanone,
A resist solution was prepared by filtration using a 0.2 micron filter.

This resist solution was applied onto a silicon wafer and
It was pre-cured in an oven for 10 minutes at °C. The wafer was cooled to room temperature and a 250 nm Dee film was applied through a mask.
PU■ light was irradiated. After irradiation, the film was heated on a hot plate at 110° C. for 2 minutes, returned to room temperature, and then developed by immersing it in a 2% aqueous solution of tetramethylammonium hydroxide for 2 minutes.

Through this series of operations, a good pattern with lines and spaces of 0.35 microns was obtained.

Examples 2 to 10 The compounds shown in Table 1 were synthesized in the same manner as in Example 1, and resist solutions were prepared in the same manner as in Example 1.

A pattern was formed by the same operation as in Example 1. As shown in Table 2, both have high sensitivity of 0.3
A good pattern with a shape of 5 microns was obtained.

[Effects of the Invention] The pattern forming material of the present invention has extremely high sensitivity to radiation and is a material useful for forming ultrafine patterns.

Claims (1)

[Scope of Claims] (a) an alkali-soluble polymer compound; (b) a compound that can act as a solubility inhibitor for the alkali-soluble polymer compound; or a cross-linking agent for the alkali-soluble polymer compound; In a pattern forming material consisting of a compound (c) that acts as a group and a compound that generates an acid upon irradiation with radiation, (c) has the general formula (
I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・
(I) (In the formula, R_1 represents a monovalent oxime residue, R_3 represents an n-valent oxime residue, R_2 represents an m-valent alkyl group or aryl group, and R_4 represents a monovalent alkyl group or aryl group. (wherein X represents either SO_2 or CO.) A pattern forming material characterized by being a compound represented by the following.