JPH07319158A - Positive type resist composition - Google Patents

Abstract

PURPOSE:To obtain this resist compsn. excellent in balance of various properties such as sensitivity, resolution, gamma-value, heat resistance, profile and the depth of focus and free from residue on development by using a specified compd. of novolak type resin, using a methylol compd. CONSTITUTION:This resist compsn. contains a photosensitive agent and alkali- soluble novolak resin. The photosensitive agent is 1,2- naphthoquinonediazidosulfonic ester of novolak type resin obtd. by allowing a methylol compd. represented by formula I to react with phenol represented by formula II in the presence of an acid catalyst. The novolak type resin consists of >=50wt.% tetranuclear compd. represented by formula III, <=10wt.% low mol.wt. component having a lower mol.wt. than the tetranuclear compd. and <=40wt.% high mol.wt. component having a higher mol.wt. than the tetranuclear compd. In the formulae I-III, each of R1-R10 is alkoxy, alkyl, hydroxyl, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive resist composition suitable as a resist for producing highly integrated circuits which is sensitive to radiation such as ultraviolet rays and deep ultraviolet rays (including excimer lasers).

[0002]

2. Description of the Related Art As a resist for producing a highly integrated circuit, for example, JP-A-6-67418 discloses an alkali-soluble novolak resin and the following formula.

[0003]

[Chemical 8]

[Wherein R ¹ is the same or different and has 1 carbon atom
To C10 alkyl group, C1 to C7 alkoxy group, C1 to C7 acyl group, C6 to C10 aryl group, C2 to C6 alkenyl group, C6 to C10 aryloxy Represents a substituent selected from a group and an alkoxycarbonyl group having 2 to 10 carbon atoms, R ² and R ³ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or 6 to 6 carbon atoms.
Selected from an aryl group having 10 carbon atoms, an aralkyl group having 6 to 10 carbon atoms and a furyl group, m represents an integer of 0 to 3, and n
Represents an integer of 1 to 3 (provided that m + n ≦ 4)], the standard polystyrene-converted weight average molecular weight (Mw) by GPC is 4000 or less, and Mw and number average molecular weight (Mn Corresponding to a condensate of a phenolic resin and quinonediazide sulfonic acid having a ratio (Mw / Mn) of less than 2.5 and an area ratio of the mononuclear and dinuclear components to the total eluted components of less than 15%, A positive-type radiation-sensitive resin composition is described, which comprises a quinonediazide compound having an average condensation rate of quinonediazidesulfonyl groups with respect to hydroxyl groups of 75% or less. However, this composition was unsatisfactory from the viewpoint of resolution or γ value.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and has an excellent balance of various performances such as sensitivity, resolution, γ value, heat resistance, profile and depth of focus.
Moreover, a positive resist composition having no development residue (scum) is provided.

[0006]

The present invention is a positive resist composition containing a photosensitizer and an alkali-soluble novolac resin, wherein the photosensitizer is represented by the general formula (Ia) or (Ib).

[0007]

[Chemical 9]

(In the formula, R ₁ and R ₂ are each independently a chain alkoxy group having 6 or less carbon atoms, a chain or cyclic alkyl group having 6 or less carbon atoms, a hydrogen atom, a hydroxyl group, or 6 carbon atoms. R ₃ represents a phenyl group which may have one or more substituents selected from the group consisting of the following chain alkoxy groups and chain or cyclic alkyl groups having 6 or less carbon atoms, and R ₃
To R ₆ each independently represent a hydroxyl group, a hydrogen atom, a chain alkoxy group having 6 or less carbon atoms, or a chain or cyclic alkyl group having 6 or less carbon atoms, and m ₀ represents an integer of ₀ to 6. ) And a general formula (II)

[0009]

[Chemical 10]

(In the formula, R _{7 to} R ₁₀ each independently represent a hydroxyl group, a hydrogen atom, a chain alkoxy group having 6 or less carbon atoms, or a chain or cyclic alkyl group having 6 or less carbon atoms). Is a 1,2-naphthoquinonediazide sulfonic acid ester of a novolak type resin obtained by reacting the indicated phenols in the presence of an acid catalyst, and the novolak type resin is represented by the general formula (IIIa) or (IIIb).

[0011]

[Chemical 11]

[0012]

[Chemical 12]

(Wherein R _{1 to} R ₁₀ and m ₀ have the same meanings as described above), 50% by weight or more of the tetranuclear compound, a low molecular weight component having a smaller molecular weight than the tetranuclear compound. A positive resist composition comprising 10% by weight or less (including unreacted methylol compound and phenols) and 40% by weight or less of a high molecular weight component having a higher molecular weight than a tetranuclear compound. .

The novolak type resin obtained by reacting the methylol compound represented by the general formula (Ia) and the phenol represented by the general formula (II) is represented by the following formula:

[0015]

[Chemical 13]

(In the formula, R _{1 to} R ₁₀ have the above-mentioned meanings,
n ₀ represents an integer of 0 or more. ), The general formula (I
The novolac type resin obtained by reacting the methylol compound represented by b) and the phenol represented by the general formula (II) is represented by the following formula:

[0017]

[Chemical 14]

[Wherein R _{3 to} R ₁₀ and n ₀ have the above-mentioned meanings, and W is the following formula:

[0019]

[Chemical 15]

(In the formula, m ₀ represents the above-mentioned meaning). ] Is shown.

In the general formulas (Ia) and (Ib), R ₃
At least one of R ₆ to R ₆ is preferably a hydroxyl group, and at least one of the o- or p-positions of the hydroxyl group is a chain (linear or branched) alkyl group having 6 or less carbon atoms. Is more preferable. The methylol compound is preferably a compound represented by the general formula (Ia), and a particularly preferable methylol compound is, for example, the following formula (c).

[0022]

[Chemical 16]

And the like. Examples of the phenols represented by the general formula (II) include phenol, o-cresol, m-cresol, p-cresol, 2,5-xylenol, 2,3-xylenol, 2,4-xylenol, 3,4-. Xylenol, 3,5-xylenol,
2,6-xylenol, 2,3,5-trimethylphenol, 2,3,6-trimethylphenol, 2-t-butyl-5-methylphenol, 2-i-propyl-5-
Examples thereof include methylphenol, 2-cyclohexyl-5-methylphenol, resorcinol, 2-methylresorcinol, catechol and pyrogallol. Preferable phenols include, for example, phenol, cresol and xylenol, and particularly preferable phenols include phenol, m-cresol, p-cresol, 2,5-xylenol, 2,6-xylenol and 3,5-xylenol. At least one phenol selected from the group consisting of Examples of the acid catalyst include organic acids such as p-toluenesulfonic acid and inorganic acids (hydrochloric acid, sulfuric acid, etc.). A methylol compound represented by the general formula (Ia) or (Ib) and a general formula (I
The reaction of the phenols represented by I) is preferably carried out in the presence of an organic solvent such as a lower aliphatic alcohol (methanol, ethanol, etc.). The reaction temperature is preferably 10 to 60
C., and the amounts of the methylol compound, phenols and acid catalyst used, and the reaction time are appropriately set.

As the novolak type resin represented by the above formula, which contains the tetranuclear compound represented by the general formula (IIIa) or (IIIb), one containing 75% by weight or more of the tetranuclear compound is preferable. The content of the low molecular weight component having a smaller molecular weight than the tetranuclear compound in the resin is preferably 5% by weight.
Similarly, the content of the high molecular weight component having a higher molecular weight than that of the tetranuclear compound is preferably 25% by weight or less. The tetranuclear compound is preferably a compound represented by the general formula (IIIa), and more preferable tetranuclear compounds include, for example, the following formula (d)

[0025]

[Chemical 17]

Examples thereof include compounds represented by

The 1,2-naphthoquinone diazide sulfonic acid ester is a novolac type resin represented by the above formula,
It can be produced by reacting 2-naphthoquinonediazide-5- (or-4-) sulfonic acid chloride in the presence of, for example, an organic base (triethylamine, pyridine, etc.) and the like.

As the alkali-soluble novolac resin,
For example, o-cresol, m-cresol, p-cresol, 2,5-xylenol, 3,5-xylenol,
3,4-xylenol, 2,3,5-trimethylphenol, 2-i-propyl-5-methylphenol, 2-
One phenol compound selected from cyclohexyl-5-methylphenol, 2-t-butyl-5-methylphenol and the like, or a mixture of two or more kinds thereof, an aliphatic aldehyde (formaldehyde, acetaldehyde, glyoxal and the like) and an aromatic aldehyde ( Benzaldehyde, salicylaldehyde, etc.) and an organic acid (oxalic acid, acetic acid, p-toluenesulfonic acid, etc.), an inorganic acid (hydrochloric acid, sulfuric acid, phosphoric acid, etc.) A resin obtained by condensation in the presence of a catalyst selected from valent metal salts (zinc acetate, etc.) in the presence of a reaction solvent or without using a reaction solvent can be mentioned. Formaldehyde etc. are mentioned as a preferable aldehyde. The condensation reaction is usually performed at a temperature of 60 to 120 ° C. for about 2 to about 30 hours. From the viewpoint of scum, the alkali-soluble novolac resin obtained by condensation is preferably subjected to an operation such as fractionation so that the area of the component having a polystyrene equivalent molecular weight of 900 or less is unreacted phenol in the GPC pattern (using a uv254nm detector). It can be 25% or less (more preferably 20% or less) with respect to the total area excluding the area of the compound. Alkali-soluble novolak resins obtained by condensation are used for separation, for example, alcohols (methanol and ethanol, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), ethylene glycol ethers, ether esters (ethyl cellosolve acetate, etc.) and ethers. Dissolve in a good solvent such as compounds (tetrahydrofuran) and then pour the obtained solution into water to precipitate it, or mix the solution with a solvent such as pentane, hexane and heptane to separate the solution. Be seen. A positive resist composition in which an alkali-soluble compound having two or more phenolic hydroxyl groups and a molecular weight of less than 900 is further added to the photosensitizer and the separated alkali-soluble novolac resin is particularly preferable from the viewpoint of various performances. Preferred alkali-soluble compounds include, for example, Antigen W and general formula (IV)

[0029]

[Chemical 18]

(In the formula, R₁₁Is a hydrogen atom or a carbon number of 6 or less
Represents a chain alkyl group of₁₂~ R ₁₇Is a hydrogen atom or
Represents a chain or cyclic alkyl group having 6 or less carbon atoms,
p represents 0 or 1. ) A compound represented by

[0031]

[Chemical 19]

Examples thereof include compounds represented by: When the above alkali-soluble compound is added, a more preferable amount is 3 to 40% by weight based on the total solid content of the positive resist composition.
Is. The preferred amount of the photosensitizer used is 10 to 50% by weight based on the total solid content of the positive resist composition. The resist solution is prepared by mixing the above-mentioned solid content with a resist solvent which has an appropriate drying rate and gives a uniform and smooth coating film when the solvent evaporates. Examples of such a solvent include ethyl cellosolve acetate, propylene glycol monomethyl acetate, n-amyl acetate,
Examples thereof include ethyl lactate, 2-heptanone and γ-butyrolactone.

[0033]

The positive resist composition of the present invention has sensitivity,
Excellent balance of performance such as resolution, γ value, heat resistance, profile and depth of focus, and no scum.

[0034]

EXAMPLES Next, the present invention will be described more specifically with reference to examples. In the examples, “part” means “part by weight”.

Synthesis Example 1 Bisphenol C 69.1 g, caustic soda 25.9 g and water 476 g
130.8 g of 37% formalin was added dropwise to the mixture at room temperature over 2 hours. After completion of dropping, the mixture was stirred at the same temperature for 4 hours. Then, 46.7 g of glacial acetic acid was added and stirred for 30 minutes. Ethyl acetate 30
After adding 0 g, the obtained mixture was washed 6 times with ion-exchanged water, and the oil layer obtained after washing was concentrated with an evaporator to distill off ethyl acetate. 1 L of methanol was added to the obtained concentrated residue, and then concentrated by an evaporator until the total amount became 200 g to obtain a methanol solution of the methylol compound represented by the above formula (c).

Synthesis Example 2 303 g of 2,5-xylenol, p-toluenesulfonic acid 2
The methanol solution obtained in Synthesis Example 1 was added dropwise to a mixture of 3.6 g and 302 g of methanol at about 35 ° C. After the completion of dropping, the mixture was stirred at the same temperature for 10 hours. After adding 600 g of toluene, wash with water,
Then the oil layer was concentrated by an evaporator. After filtering the obtained residue, the filtrate was added dropwise to 1 kg of n-heptane while stirring. The precipitate is dissolved in toluene and n-heptane 60 is added.
It was added dropwise to 0 g with stirring. After filtering the precipitate, the product on the filter was washed with n-heptane and then dried to obtain 28.6 g of novolac type resin A. As a result of GPC analysis (using a uv254nm detector), the content of the tetranuclear compound represented by the formula (d) was 86.5%, the content of the high molecular weight component was 13.4%, and the content of the low molecular weight component was The amount was 0.1%.

Synthesis Example 3 268.6 g of o-cresol, 23.6 g of p-toluenesulfonic acid
A methanol solution obtained in the same manner as in Synthesis Example 1 was added dropwise to a mixture of and 302 g of methanol at about 35 ° C. After the dropping is completed,
The mixture was stirred at the same temperature for 10 hours. After adding 600 g of ethyl acetate and washing with water, 1 kg of toluene was added and the mixture was concentrated with an evaporator. The obtained residue was added dropwise to 1 Kg of n-heptane while stirring. The precipitate was dissolved in toluene, and thereafter, Synthesis Example 2
In the same manner as above, 81.48 g of novolak type resin B was obtained. As a result of the analysis, the content of the tetranuclear compound represented by the following formula (e) is
84.9%, the content of high molecular weight component is 15.0%,
The content of low molecular weight components was 0.1%.

[0038]

[Chemical 20]

Synthesis Example 4 To a mixture of 233.8 g of phenol, 23.6 g of p-toluenesulfonic acid and 302 g of methanol, a methanol solution obtained in the same manner as in Synthesis Example 1 was added dropwise at about 35 ° C. 50 ° C after dropping
The mixture was stirred for 10 hours and then 600 g of toluene was added. 70 ° C
After washing with water, the oil layer was concentrated. 1Kg of methanol in the concentrated residue
Was added and the mixture was concentrated, and the obtained residue was added dropwise to 1 Kg of water with stirring. The obtained precipitate was diluted with methanol and then added dropwise to 600 g of water while stirring. The obtained precipitate was washed with a mixed solution of water and methanol (3: 1) and then dried to obtain 78.5 g of novolac type resin C. As a result of the analysis, the content of the tetranuclear compound represented by the following formula (f) was 77.2.
%, The content of high molecular weight components was 22.7%, and the content of low molecular weight components was 0.1%.

[0040]

[Chemical 21]

Synthesis Example 5 In a mixture of 3 g of the novolak type resin A obtained in Synthesis Example 2, 3.4 g of 1,2-naphthoquinonediazide-5-sulfonic acid chloride and 32.2 g of dioxane, 1.5 g of triethylamine was added.
The solution was added dropwise at -30 ° C over 1 hour and then stirred at 30 ° C for 7 hours. Furthermore, 1 g of acetic acid was added, and the mixture was stirred at the same temperature for 1 hour. Then, the reaction mixture was filtered, and the obtained filtered product was washed with 5 g of dioxane. The filter washing solution was poured into 300 g of ion-exchanged water containing 1.9 g of acetic acid, and then stirred for 1 hour. The precipitate was filtered, and the product on the filter was washed in 300 g of ion-exchanged water while stirring. The crystals after filtration were dried at 40 ° C. to obtain a photosensitizer D.

Synthetic Example 6 1.2 g of triethylamine was added to a mixture of 2 g of the novolak type resin B obtained in Synthetic Example 3, 2.7 g of 1,2-naphthoquinonediazide-5-sulfonic acid chloride and 23.5 g of dioxane.
The solution was added dropwise at -30 ° C over 1 hour and then stirred at 30 ° C for 7 hours. Furthermore, 1 g of acetic acid was added, and the mixture was stirred at the same temperature for 1 hour. Then, the reaction mixture was filtered, and the obtained filtered product was washed with 5 g of dioxane. The filter washing solution was poured into 400 g of ion-exchanged water containing 1.4 g of acetic acid, and then stirred for 1 hour. The precipitate was filtered, and the product on the filter was washed in 300 g of ion-exchanged water while stirring. The crystals after filtration were dried at 40 ° C. to obtain a photosensitizer E. Synthetic Example 7 In a mixture of 9 g of the novolak type resin C obtained in Synthetic Example 4, 9.4 g of 1,2-naphthoquinonediazide-5-sulfonic acid chloride and 92.1 g of dioxane, 4.3 g of triethylamine was added.
The solution was added dropwise at -30 ° C over 1 hour and then stirred at 30 ° C for 7 hours. Further, 1.5 g of acetic acid was added, and the mixture was stirred at the same temperature for 1 hour. Then, the reaction mixture was filtered, and the obtained filtered product was washed with 9.4 g of dioxane. The filter washing solution was poured into 508 g of ion-exchanged water containing 5.1 g of acetic acid, and then stirred for 1 hour. The precipitate was filtered, and the filter cake was washed with 648 g of ion-exchanged water while stirring, and then a photosensitizer F was obtained in the same manner as in Synthesis Example 6.

Synthesis Example 8 m-cresol 148.5 g, p-cresol 121.5 g, methyl isobutyl ketone 252 g, 10% oxalic acid 37 g and 90% acetic acid 84.8.
129.5 g of 37% formalin was added dropwise to the mixture of g at 100 ° C. over 40 minutes. After the dropping was completed, the reaction was carried out at the same temperature for 15 hours.
After cooling, it was washed with water and then dehydrated to obtain a solution of novolac resin in methyl isobutyl ketone (resin content: 42.3%). GPC
The polystyrene-reduced weight average molecular weight was 4,300. 450 g of the above solution, 910 g of methyl isobutyl ketone and n
Stirring the mixture of 996 g of heptane at 60 ° C. for 30 minutes, then allowing it to stand,
Then, the layers were separated. After adding 380 g of 2-heptanone to the obtained lower layer, methyl isobutyl ketone and n-heptane were removed by an evaporator to obtain a 2-heptanone solution of novolak resin G. The polystyrene-converted weight average molecular weight by GPC is 9000, and the area of components with a molecular weight of 900 or less is m.
-For all areas except cresol and p-cresol
It was 17%.

Examples (Example Nos. 1 to 3) The novolak resin G obtained in Synthesis Example 8, the photosensitizer, and the additive H represented by the following formula had the composition shown in the following table and 50 parts of 2-heptanone.
After mixing so as to form parts, a resist solution was prepared by filtering with a filter having a pore size of 0.2 μm.

[0045]

[Chemical formula 22]

A silicon wafer washed by a conventional method was coated with the above resist solution to a thickness of 1.1 μm using a spinner and baked at 90 ° C. for 1 minute on a hot plate. Then 36
Reduction projection exposure tool with exposure wavelength of 5 nm (i-line) (Nikon N
SR1755i7A NA = 0.5) was used to change the exposure amount stepwise. Then, it was baked on a hot plate at 110 ° C. for 1 minute. Then, it was developed with an alkaline developer SOPD [Sumitomo Chemical Co., Ltd.] for 1 minute to obtain a positive pattern. The sensitivity was measured by the exposure amount at which the line and space pattern of 50 μm became 1: 1. The resolution was the effective sensitivity, and the dimensions of the line-and-space pattern that separated without film loss were observed with a scanning electron microscope. As for the profile and scum, the cross-sectional shape of the 0.45 μm line-and-space pattern in effective sensitivity was observed with a scanning electron microscope. Heat resistance is 124 ° C
Was heated on a hot plate for 5 minutes and the degree of sagging of the resist pattern was evaluated on a scale of 5 (5 is the best, 1 is the worst). Regarding the depth of focus, the width of the focus at which the 0.40 μm line-and-space pattern at the effective sensitivity is separated without film loss was observed with a scanning electron microscope.

[0047]

[Table 1]

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasunori Uetani 3-98 Kasugade, Konohana-ku, Osaka City, Osaka Prefecture Sumitomo Chemical Co., Ltd. (72) Inventor Yoshiyuki Takada Kasuga, Konohana-ku, Osaka City, Osaka Prefecture 3-3-198 Naka Sumitomo Chemical Co., Ltd. (72) Inventor Haruki Ozaki 3-1-198 Kasuga, Konohana-ku, Osaka City, Osaka Prefecture Sumitomo Chemical Co., Ltd.

Claims (7)

[Claims] 1. A positive resist composition containing a photosensitizer and an alkali-soluble novolac resin, wherein the photosensitizer is represented by the general formula (Ia) or (Ib): (In the formula, R ₁ and R ₂ are each independently a chain alkoxy group having 6 or less carbon atoms, a chain or cyclic alkyl group having 6 or less carbon atoms, a hydrogen atom, or a hydroxyl group, a chain having 6 or less carbon atoms. Represents a phenyl group optionally having one or more substituents selected from the group consisting of a linear alkoxy group and a chain or cyclic alkyl group having 6 or less carbon atoms, and R _{3 to} R ₆ are each independently A hydroxyl group, a hydrogen atom, a chain-like alkoxy group having 6 or less carbon atoms or a chain-like or cyclic alkyl group having 6 or less carbon atoms, and m ₀ represents an integer of ₀ to 6) and general Formula (II): (In the formula, R _{7 to} R ₁₀ are each independently a hydroxyl group, a hydrogen atom,
It represents a chain alkoxy group having 6 or less carbon atoms or a chain or cyclic alkyl group having 6 or less carbon atoms. ) Is a 1,2-naphthoquinonediazide sulfonic acid ester of a novolak type resin obtained by reacting a phenol represented by the formula (1) in the presence of an acid catalyst, and the novolak type resin is represented by the general formula (IIIa) or (IIIb). [Chemical 3] [Chemical 4] (In the formula, R _{1 to} R ₁₀ and m ₀ have the same meanings as described above.) 50% by weight or more of the tetranuclear compound represented by
Consist of less than 10% by weight of low molecular weight components (including unreacted methylol compounds and phenols) having a lower molecular weight than nucleoside compounds, and 40% by weight or less of high molecular weight components having a greater molecular weight than tetranuclear compounds A positive resist composition comprising: 2. An alkali-soluble novolak resin is a GP thereof.
The positive resist composition according to claim 1, wherein the area ratio in the range of 900 or less in terms of polystyrene equivalent molecular weight in the C pattern is 25% or less with respect to the total pattern area excluding the pattern area of the unreacted phenol compound. 3. The positive resist composition according to claim 1, further comprising an alkali-soluble compound having two or more phenolic hydroxyl groups and a molecular weight of less than 900. 4. A molecule having two or more phenolic hydroxyl groups.
An alkali-soluble compound having an amount of less than 900 is represented by the general formula (IV):(In the formula, R₁₁Is a hydrogen atom or a chain alkyl group having 6 or less carbon atoms
Represents a group, R₁₂~ R ₁₇Is a hydrogen atom or a carbon number of 6 or less
Represents a chain or cyclic alkyl group of p is 0 or 1
Represents 4. The compound according to claim 3, which is a compound represented by
Positive resist composition. 5. A methylol compound represented by the general formula (Ia) is represented by the following formula (c): The positive resist composition according to claim 1, which is a compound represented by 6. Phenols represented by the general formula (II) are phenol, m-cresol, p-cresol and 2,5.
The positive resist composition according to claim 1, which is at least one phenol selected from the group consisting of -xylenol, 2,6-xylenol and 3,5-xylenol. 7. A tetranuclear compound represented by the general formula (IIIa) is represented by the following formula (d): The positive resist composition according to claim 1, which is a compound represented by