JP2964733B2 - Pattern forming material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern forming material used for forming a high-precision fine pattern.

[0002]

2. Description of the Related Art In general, patterning for fine processing of a semiconductor device or the like is performed by a photoengraving method. In this case, a resist that is sensitive to actinic rays such as radiation is used. Conventionally, as such a material, a material that is decomposed by being irradiated with radiation or a compound that is cured by being irradiated with radiation has been used as the resist. . However, since these compounds undergo only a sequential reaction and react with the irradiation energy, their efficiencies are extremely low and a significant improvement in sensitivity cannot be expected.

In recent years, in order to solve such problems, a resist based on the idea of a chemical amplification mechanism has been studied.
This is a technique in which an acid generated by light irradiation is used as a catalyst to thermally promote the reaction other than light. In this method, the amount of light irradiation only needs to generate a catalytic amount of acid, so that extremely high sensitivity can be achieved.

On the other hand, the characteristics required for resist materials are as follows:
With the recent progress in pattern miniaturization, it has become increasingly sophisticated, and it is extremely difficult to satisfy all the characteristics only by forming a resist with a single polymer compound. Therefore, the idea of a multi-system resist using several materials in combination to share each characteristic has been proposed. As a resist considering these two ideas, for example, Polymer
Engineering Science Volume 26
1101, pp. (1986) novolak described in resin, melamine resin, made of acid generator resist or, JP
A resist composed of a novolak resin, an acetal compound, an acid generator and the like described in JP-A-1-106040 have been proposed.

[0005]

However, the former has a negative type photosensitivity, swells due to a developing solution and the like, and cannot improve the resolution. On the other hand, in the case of the latter, the above-mentioned swelling can be avoided because of the positive type. However, since the unexposed portion is dissolved to some extent, film thinning occurs during development, and there are problems such as a decrease in resolution and a decrease in pattern accuracy. The present invention has been made in order to solve the problems of the prior art as described above, and only high sensitivity to radiation and only exposed portions are faithfully dissolved in the developing solution, and further, the unexposed portions of the developing solution are removed. An object of the present invention is to provide a positive pattern forming material which does not cause the dissolution of the compound.

[0006]

Means for Solving the Problems A first invention of the present invention is:
A polymer compound (a) represented by the following chemical formula 2,

Embedded image A pattern forming material having a composition comprising a compound (b) that generates an acid or a base upon irradiation with radiation.

The second invention comprises a polymer compound (a) represented by the above formula (2), a compound (b) generating an acid or a base upon irradiation with radiation, and an alkali compound decomposed by the acid or the base. This is a pattern forming material having a composition comprising the compound (c) that becomes soluble.

The polymer compound (a) used in the present invention can be synthesized from a vinylphenol compound represented by the following formula (3) and an acrylic compound represented by the following formula (4).

Embedded image

Embedded image

These compounds can be synthesized by radical polymerization, ionic polymerization or the like. As for the composition of the copolymer, the vinylphenol compound (2) was mixed in the range of 0.6 to 0.9 mol and the acrylic compound (3) in the range of 0.4 to 0.1 mol, and the total was mixed. The reaction is preferably performed at a composition ratio of 1 mol. The above vinylphenol compound (2)
In the case of 6 moles or less [the amount of the acrylic compound (3) is 0.4 moles or more], the dry etching resistance when formed into a resist is inferior, and further, the adhesiveness to the substrate is reduced, and the resist is not developed. The flow of the minute pattern is likely to occur.

In particular, the presence of hydroxyl groups in the vinylphenol-based compound (2) is important because the presence of hydroxyl groups gives an effect of enhancing the adhesiveness to a substrate when used as a resist. In addition, the vinylphenol compound (2) was added to 0.1%.
In the case of 9 mol or more [the amount of the acrylic compound (3) is 0.1 mol or less], when a resist is used, a difference in dissolution between exposed and unexposed is not obtained, which causes a reduction in film thickness during development. .

The average molecular weight of the synthetic polymer is desirably about 2000 to 50,000 from a practical viewpoint. Molecular weight 2
When the molecular weight is less than 000, uniform coating properties cannot be obtained, and when the molecular weight is more than 50,000, the solubility of exposed portions during development is reduced, which may cause generation of development residues. In the acrylic compound (3), R ₄ in the formula may be anything as long as it is a tertiary alcohol residue and an allyl group.
Examples thereof include a butyl group, a t-amyl group, a t- (triethyl) methyl group, a 1-methyl-1-cyclohexyl group, and a 2-cyclohexene group.

Next, as the compound (b) which generates an acid upon irradiation with radiation used in the present invention, for example, triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluoroarsinate , Triphenylsulfonium hexafluorophosphate, triphenylsulfonium trifluorosulfonate,

4-thiophenoxydiphenylsulfonium tetrafluoroborate; 4-thiophenoxydiphenylsulfonium hexafluoroantimonate;
Thiophenoxydiphenylsulfonium hexafluoroarsinate, 4-thiophenoxydiphenylsulfonium hexafluorophosphate, 4-thiophenoxydiphenylsulfonium trifluorosulfonate,

4-tert-butylphenyldiphenylsulfonium tetrafluoroborate, 4-tert-butylphenyldiphenylsulfonium trifluorosulfonate, tris (4-methoxyphenyl) sulfonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, Diphenyl iodonium hexafluoroantimonate, diphenyl iodonium hexafluoroarsinate, diphenyl iodonium hexafluorophosphate, diphenyl iodonium trifluorosulfonate,

3,3'-dinitrodiphenyliodonium trifluorosulfonate, 4,4'-dimethyldiphenyliodonium tetrafluoroborate, 4,4 '
-Dimethyldiphenyliodonium hexafluoroantimonate, 4,4'-dimethyldiphenyliodonium trifluorosulfonate, 4,4'-ditert-butyldiphenyliodonium hexafluoroantimonate, 4,4'-ditert-butyl Onium salts such as diphenyliodonium hexafluorophosphate, 4,4'-ditert-butyldiphenyliodonium trifluorosulfonate,

2,4,6-tris (trichloromethyl)
Triazine, 2-allyl-4,6-bis (trichloromethyl) triazine, α, α, α-tribromomethyl-phenylsulfone, α, α, α, α ′, α ′, α′-hexachloroxylylene, , 2-Bis (3,5-dibromo-4-hydroxyphenyl) -1,1,1,3,3,3
-Hexafluoropropane, 1,1,1-tris (3,
Halogen-containing compounds such as 5-dibromo-4-hydroxyphenyl) ethane,

(2-nitrobenzyl tosylate, 2,6
-Dinitrobenzyl tosylate, 2,4-dinitrobenzyl tosylate, methyl sulfonic acid 2-nitrobenzyl ester, acetic acid 2-nitrobenzyl ester, p-nitrobenzyl-9,10-dimethoxyanthracene-2-
Sulfonates such as sulfonates can be mentioned.

The compound (b) which generates a base upon irradiation with radiation includes, for example, 1,1,1-triphenylmethanol, 1,1,1-tri (methoxyphenyl) methanol, 1,1 , 1-tri (methylphenyl)
Methanol, 1,1,1-tri (nitrophenyl) methanol, 1,1,1-triphenylcyanomethane, 1,
1,1-tri (methoxyphenyl) cyanomethane, 1,
1,1-tri (methylphenyl) cyanomethane,

2-nitrobenzyl N-cyclohexacarbamate, 2-nitrobenzyl N-phenylcarbamate, 2-nitrobenzyl N-alkylcarbamate,
2,6-dinitrobenzyl N-phenylcarbamate,
2,6-dinitrobenzyl N-alkyl carbamates,
And the like.

Next, the compound (c) which is decomposed by an acid or a base and becomes alkali-soluble in the present invention includes an ester compound represented by the following formula:

Embedded image Or a carbonate compound represented by the following formula:

Embedded image Alternatively, an oxime ester compound represented by the following formula 7 can be selected.

Embedded image

An oxime ester compound represented by the above formula (7)
The compound can be easily synthesized by reacting the acid chloride with the corresponding oxime compound . Examples of acid chlorides include, for example, 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,
Examples thereof include benzene trisulfonic acid chloride, diphenyl ether disulfonic acid chloride, polyphenylmethane disulfonic acid chloride, hexamethylene dicarboxylic acid chloride, cyclohexyl dicarboxylic acid chloride, and butanetetracarboxylic acid chloride.

The carbonate compound represented by the chemical formula 6 includes bisphenol A, bisphenol S, biphenol, catechol, phloroglicinol, pyrogallol ,
It can be easily synthesized by reacting tri 2phenoxymethane, and a tri-phenoxymethyl ethane such <br/> any phenolic compounds and di t- butyl dicarbonate.

Further, the oxime ester compound represented by Chemical formula 7 can be synthesized by reacting the above-mentioned acid chloride with oximes such as acetoxime, cyclohexane oxime, acetophenone oxime and benzophenone oxime.

In the first invention, 99.5 to 80% of the compound (a) and 0.05 to 5% of the compound (b) are included in the above-mentioned components.
It is appropriate to select within a range of 20%. When the content of the compound (b) is 0.05% or less, a good pattern cannot be formed, and when it exceeds 20%, a residue may be generated during development or compatibility may be obtained. Disappears.

Further, in the second invention, 90% to 40% of the compound (a) and 0.05% of the compound (b)
It is appropriate to select within the range of about 20% and the proportion of compound (c) 10 to 60%. When the amount of the compound (a) is 90% or more, the amount of the compound (c) is small, so that patterning by exposure becomes difficult. Invite. Compound (b) is 0.0
If it is less than 5%, a good pattern cannot be formed, and if it exceeds 20%, a residue will be generated during development or compatibility of the three components cannot be obtained.

The pattern forming material of the present invention is prepared as a solution, which is applied using a spin coater or the like, and the solvent used at that time is generally an exception if it does not react with the above three components. Can be used without. For example, cellosolve acetate, dimethyl glyme, dimethyl diglyme, cyclohexanone, cyclopentanone, methyl isobutyl ketone, isoamyl acetate,
Dioxane and the like are common.

In actual pattern formation, a solution containing the above-described pattern forming material of the present invention is applied to a substrate such as a silicone wafer, heated for solvent removal, and then a mask having a predetermined pattern is formed. (In case of electron beam, drawing), then 60-1
Heating is performed at 50 ° C., followed by development. As the developer, an aqueous solution of ammonia, triethylamine, dimethylethanol, tetramethylammonium hydroxide, sodium hydroxide, sodium carbonate, or the like can be used.

The pattern-forming material of the present invention is composed of two or three components as described above, and an adhesion improver (for example, aminosilazane) for improving the adhesion between the substrate and the material of the present invention. , Aminoalkoxysilanes, alkylalkoxysilanes, metal chelates, etc.) and other compounds as desired can be added. The pattern forming material of the present invention can be used as a resist for fine processing that requires fine patterning, such as a semiconductor element and a printed wiring board.

[0029]

According to the first aspect of the present invention, upon irradiation with radiation, an acid or a base is generated at the exposed portion, and the generated acid or base decomposes the alkyl ester group of the polymer compound (a) to form a carboxylic acid. As a result, the solubility of the exposed portion of the composition is greatly improved. On the other hand, in the unexposed portion, the polymer compound (a) has a portion of the alkali-soluble group of the polymer compound protected by an alkyl ester group.
Lower solubility than all degraded polymer compounds. Therefore, the solubility difference between the exposed part and the unexposed part can be greatly improved, and a high-resolution pattern can be formed.

Further, in the second invention, irradiation with radiation generates an acid or a base in the exposed portion,
The compound (c) which is decomposed by the acid or base and becomes alkali-soluble becomes alkali-soluble by the generated acid or base, and at the same time, the alkyl ester group of the polymer compound (a) is decomposed to generate a carboxylic acid. And the solubility of the exposed portion of the composition is greatly improved. on the other hand,
In the unexposed area, the polymer compound (a) has a higher concentration than the polymer compound in which all of the alkyl ester groups are decomposed because the presence of the compound (c) and a part of the alkali-soluble group are protected by the alkyl ester group. Extremely low solubility. Therefore, the solubility difference between the exposed part and the unexposed part can be greatly improved, and a high-resolution pattern can be formed.

[0031]

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

Example 1 Synthesis of polymer compound (a: PVMB-20) 24.2 g (0.2 mol) of p-vinylphenol, 89.6 g (0.8 mol) of t-butyl methacrylate, and azobisisobutyro 3.5 g of nitrile (AIBN) and 300 g of toluene
Dissolve in mL and stir uniformly under a stream of nitrogen. Then
The temperature was raised to 80 ° C., and a heating reaction was performed for 16 hours. After the reaction,
The reaction was poured into 2 L of methanol to give a white precipitate. After being sufficiently washed with methanol, it was dried under reduced pressure.
The infrared absorption spectrum measurement, the hydroxyl group of around 3350 cm ^-1, confirming the absorption of ester bond or the like in the vicinity of 1720 cm ^-1.

Preparation of resist solution 9.5 g of the polymer compound synthesized above and 0.5 g of diphenyliodonium tetrafluoroborate were dissolved in 30 g of cyclohexanone, and the solution was filtered using a 0.2-micron filter to obtain a resist solution. Was prepared. This resist solution was applied on a silicon wafer and precured in an oven at 80 ° C. for 10 minutes to obtain a 0.9 μm film. The wafer is cooled to room temperature and passed through a mask for 2 hours.
Irradiation with 50 nm Deep UV light was performed. After the irradiation, the substrate was heated on a hot plate at 110 ° C. for 2 minutes, returned to room temperature, and immersed in a 2% aqueous solution of tetramethylammonium hydroxide for 2 minutes to perform development. In this series of operations, 0.
Good patterns with a line and space of 35 microns were obtained.

Examples 2 to 9 By combining the compounds (a) and (b) shown in Table 1 below,
A resist solution was prepared in the same manner as in Example 1. And
By the same operation as in Example 1, a film of 1.0 to 0.85 μm was produced, and a similar pattern was formed.
When the pattern was evaluated, as shown in Table 2,
High sensitivity, that is, a good pattern having a shape of 0.35 to 0.4 micron was obtained.

[0035]

[Table 1]

[0036]

[Table 2]

Example 10 Synthesis of Ester Compound 1 mol of t-butyl alcohol and 0.2 mol of pyridine are mixed and stirred. Next, 0.1 mol of terephthalic acid chloride is added and the mixture is stirred for 4 hours. After completion of the reaction, the reaction product is poured into water to precipitate a reaction product. Recrystallization from ethanol gave the desired di-tert-butyl terephthalate.

Preparation of Resist Solution 7 g of the polymer compound synthesized in Example 1 above, 3 g of di-tert-butyl terephthalate, and 0.3 g of diphenyliodonium tetrafluoroborate were added to cyclohexanone 25.
g, and filtered using a 0.2 micron filter to prepare a resist solution.

This resist solution was applied on a silicon wafer and precured in an oven at 80 ° C. for 10 minutes to obtain a resist solution.
A 9 micron film was obtained. The wafer was cooled to room temperature and irradiated with 250 nm Deep UV light through a mask. After the irradiation, the substrate was heated on a hot plate at 110 ° C. for 2 minutes, returned to room temperature, and immersed in a 2% aqueous solution of tetramethylammonium hydroxide for 2 minutes to perform development. Through this series of operations, a good pattern having a 0.35 micron line and space was obtained.

Examples 11 to 25 A resist solution was prepared in the same manner as in Example 1 by combining the compounds (a), (b) and (c) shown in Table 3 below.
Then, a film having a thickness of 1.0 to 0.85 μm was produced by the same operation as in Example 1, and a similar pattern was formed.
When the pattern was evaluated in the same manner, as shown in Table 4, high sensitivity, that is, a good pattern having a shape of 0.2 to 0.4 micron was obtained.

[0041]

[Table 3]

[0042]

[Table 4]

[0043]

According to the pattern forming material of the present invention, an acid or a base is generated in any of the exposed portions during radiation exposure for forming the pattern. And, by the action of the acid or the base, as described in detail above, the solubility difference between the exposed part and the unexposed part can be greatly improved, and the effect that a high-resolution pattern can be formed is exhibited. Can be solved.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shoko Tanaka 8-1-1, Tsukaguchi Honcho, Amagasaki-shi, Hyogo Mitsubishi Electric Corporation Materials and Devices Laboratory (72) Inventor Hideo Horibe 8 Tsukaguchi-Honmachi, Amagasaki-shi, Hyogo Material 1-1, Mitsubishi Electric Corp. (72) Inventor Yuji Hizuka 8-1-1, Tsukaguchi-Honmachi, Amagasaki-shi, Hyogo Prefecture Material Device Laboratory, Mitsubishi Electric Corporation (56) References JP JP-A-3-206458 (JP, A) JP-A-2-181151 (JP, A) JP-A-2-309358 (JP, A) JP-A-3-31845 (JP, A) JP-A-4-88346 (JP) , A) JP-A-4-293053 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03F 7/00-7/42 H01L 21/027

Claims (2)

(57) [Claims] 1. A polymer compound (a) represented by the following formula (1): A compound (b) that generates an acid or a base upon irradiation with radiation, and a pattern-forming material. 2. A polymer compound (a) represented by the following chemical formula 1,
A pattern-forming material comprising: a compound (b) that generates an acid or a base upon irradiation with radiation; and a compound (c) that is decomposed by the acid or the base and becomes alkali-soluble.