JPH10319587A - Radiation sensitive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the radiation sensitive resin composition superior in focus allowance and sensitivity and resolution and useful as a positive resist for producing large scale integrated circuits. SOLUTION: This radiation sensitive resin composition contains an alkali- soluble phenol resin and a quinonediazido compound, and the alkali-soluble phenol resin is a condensation product of phenols composed essentially of p- cresol and aldehydes, and, when the alkali-soluble phenol resin is measured by the pyrolytic analysis of a gas chromatgraph using a capillary column provided in the inside with a silicone phase containing permethylated α- cyclodextrine at a pyrolytic temperature of 670 deg.C, a ratio of the peak area X of the p-cresol to the peak area Y of 2,4-dimethylphenol X/Y is >=2.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a radiation-sensitive resin composition containing an alkali-soluble resin. More specifically, integrated circuits sensitive to various types of radiation such as ultraviolet rays such as g-rays and i-rays, far ultraviolet rays such as KrF excimer lasers, X-rays such as synchrotron radiation, and charged particle beams such as electron beams, particularly ultraviolet rays and far ultraviolet rays. The present invention relates to a radiation-sensitive resin composition suitable as a resist for production.

[0002]

2. Description of the Related Art With the increase in the degree of integration of integrated circuits, positive resists having high resolution and capable of forming good patterns have been developed one after another. Generally, in order to improve the resolution of a positive resist, the aperture coefficient (N
There is a method of increasing A), but in this case, the depth of focus (focus tolerance) becomes narrow, and therefore, it is necessary to improve the resist material at the same time. For example, one solution is to convert the internal structure of an alkali-soluble phenol resin into a high-ortho structure, but in this case, the sensitivity is significantly reduced. Further, in order to improve the focus tolerance, for example, it is effective to increase the amount of the quinonediazide compound added, but in this case, the developability deteriorates. Therefore, new development of a positive resist having these resist characteristics at the same time is desired.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a radiation-sensitive resin composition which is particularly useful as a resist excellent in focus tolerance and excellent in sensitivity, resolution and the like. Other objects and advantages of the present invention will become apparent below.

[0004]

According to the present invention, the above objects and advantages of the present invention are attained in a radiation-sensitive resin composition containing an alkali-soluble phenol resin and a quinonediazide compound, wherein the alkali-soluble phenol resin is p-type. -Is a condensate of phenols and aldehydes containing cresol as an essential component, and the alkali-soluble phenol resin is a pyrolysis gas chromatograph using a capillary column having a silicone phase containing permethylated α-cyclodextrin on the inner surface. And thermal decomposition temperature 6
When measured at 70 ° C., there is a relationship of X / Y ≧ 2.0 between the peak area value X of p-cresol detected as a pyrolysis product and the peak area value Y of 2,4-dimethylphenol. It can be achieved by a radiation-sensitive resin composition characterized by the following. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be specifically described, but the purpose, configuration and effect of the present invention will be clear.

[0005] The capillary column specified in the present invention is:
Preferably, permethylated α-cyclodextrin is contained in a medium-polar silicone phase chemically bonded to the inner wall of the column. As the medium polar silicone phase, poly (diphenyl-dimethylsiloxane) is preferable, and the polymerization ratio of the copolymer of diphenylsiloxane and dimethylsiloxane is diphenylsiloxane / dimethylsiloxane = 20.
４０40/80６０60 (weight ratio).
Commercial products of such a medium-polar silicone phase include SPB-20 and SPB-35 manufactured by Spelco (USA). The content of permethylated α-cyclodestrin in the silicone phase is preferably 10 to 30% by weight. A particularly suitable commercially available capillary column includes α-DEX120 manufactured by Spelco (USA).

[0006] The two peaks of the pyrolysis gas chromatograph spectrum specified in the present invention are both derived from decomposition products generated by cleaving the methylene bond between phenol rings. The degradation product derived from p-cresol is p
-Cresol, 2,4-dimethylphenol and 2,
It is understood that there are three kinds of 4,6-trimethylphenol, and the distribution of the decomposed product shifts in a direction having no methyl group as the proportion of p-cresol introduced into the terminal in the resin increases. That is, it is suggested that the larger the value of X / Y is, the more p-cresol is present at the terminal, and it is interpreted that the oo'-bonding rate at the terminal of the resin increases accordingly. The oo 'bond ratio in the conventional alkali-soluble phenol resin is regarded as an important factor for controlling the interaction with a quinonediazide compound or an alkali developing solution, that is, the alkali solubility. It is done as a whole average. On the other hand, the present invention aims to express these interactions more effectively by distributing the oo 'bond in the resin to the terminal more, and particularly, X / Y ≧
When the value of 2.0 is satisfied, the above-described effects are exhibited irrespective of the production method of the alkali-soluble phenol resin. More preferred alkali-soluble phenolic resins satisfy the relationship of X / Y ≧ 2.4.

The phenols used for producing the alkali-soluble phenol resin (hereinafter referred to as "resin (A)") used in the present invention contain p-cresol as an essential component.
Other phenols other than p-cresol include m-
Cresol, m-ethylphenol, mn-propylphenol, m-isopropylphenol, mn-butylphenol, mt-butylphenol, 2,3-
Xylenol, 2,5-xylenol, 3,4-xylenol, 3,5-xylenol, 2,3,5-trimethylphenol, alkylphenols such as 3,4,5-trimethylphenol, m-methoxyphenol, m-ethoxy Phenol, mn-butoxyphenol, mt-
Examples thereof include alkoxyphenols such as butoxyphenol. These can be used alone or in combination of two or more. Particularly preferred combinations of phenols include m-cresol, 2,3-xylenol, 2,5-xylenol, 3,4-xylenol, 3,5-xylenol and 2,3,5-trimethylphenol. And a combination of at least one phenol selected from the group consisting of p-cresol. The amount of p-cresol used is preferably from 0.1 to 0.7 mol, particularly preferably from 0.1 to 0.5 mol, per mol of all phenols used in the production of the resin (A). is there.

Examples of the combination of phenols used in the production of the resin (A) include m-cresol / p-cresol = 90-50 / 10-50 (molar ratio), m-cresol / 2,3-xylenol / p -Cresol = 75-
35 / 25-5 / 50-20 (molar ratio), m-cresol / 2,5-xylenol / p-cresol = 75-3
5 / 25-5 / 50-20 (molar ratio), m-cresol / 3,4-xylenol / p-cresol = 75-40
/ 20-5 / 50-20 (molar ratio), m-cresol /
3,5-xylenol / p-cresol = 75-40 /
20-5 / 50-20 (molar ratio) or m-cresol / 2,3,5-trimethylphenol / p-cresol =
A combination of 75 to 40/20 to 5/50 to 20 (molar ratio) is particularly preferred.

The aldehydes to be condensed include
For example, formaldehyde, trioxane, paraformaldehyde, benzaldehyde, acetaldehyde, propylaldehyde, phenylacetaldehyde, α-phenylpropylaldehyde, β-phenylpropylaldehyde, o-hydroxybenzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, o-methylbenzaldehyde, Examples thereof include m-methylbenzaldehyde, p-methylbenzaldehyde, furfural, glyoxal, glutaraldehyde, terephthalaldehyde, and isophthalaldehyde. Among these, formaldehyde and o-hydroxybenzaldehyde can be particularly preferably used.

These aldehydes can be used alone or in combination of two or more. The amount of the aldehyde used is preferably 0.4 to 2 mol, more preferably 0.6 to 1.5 mol, per 1 mol of the phenol.
As the catalyst usually used for polycondensation of phenols and aldehydes, for example, hydrochloric acid, nitric acid, inorganic acids such as sulfuric acid,
Organic acids such as formic acid, oxalic acid, acetic acid, methanesulfonic acid and p-toluenesulfonic acid, organic bases such as pyridine, 2-methylpyridine, 4-methylpyridine and tetramethylammonium hydroxide, lithium hydroxide and sodium hydroxide And inorganic bases such as magnesium hydroxide, potassium hydroxide and calcium hydroxide. The use amount of these catalysts is usually 1 × 10 ^{−5 to} 1.0 mol per 1 mol of the total amount of phenols.

The temperature of the polycondensation can be appropriately adjusted according to the reactivity of the reaction raw materials.
Preferably it is 40-150 degreeC. Polycondensation can be carried out without adding a solvent, but water derived from a formalin source is used for the purpose of controlling the elementary reaction of polycondensation and controlling the molecular weight of the polycondensed novolak resin, the position of the methylene bond, and the like. Alternatively, another reaction solvent may be added in addition to the alcohol. Examples of the polycondensation reaction solvent include water, methanol, ethanol, propanol, butanol, propylene glycol monomethyl ether, tetrahydrofuran, dioxane, toluene, xylene, and n.
-Heptane, ethyl methyl ketone, methyl isobutyl ketone, n-hexane and the like. The reaction solvents can be used alone or in combination of two or more. The amount of the reaction solvent used is usually 20 to 1,
000 parts by weight.

As the polycondensation method, phenols, aldehydes, acidic catalysts and the like are charged at once, and phenols, aldehydes, acidic catalysts and the like are added as the reaction proceeds in the presence of the acidic catalyst. A method can be adopted. After the completion of the polycondensation reaction, in order to remove unreacted raw materials, acidic catalyst, reaction solvent, and the like present in the system, generally, the temperature of the reaction system is increased to 130 to 230 ° C., and under reduced pressure, for example, Volatile components are distilled off at 20 to 50 mmHg, and the obtained resin (A) is recovered.

The resin (A) of the present invention has a weight average molecular weight in terms of polystyrene (hereinafter, referred to as "Mw") of usually 3,000 to 20,000, particularly 4,000 to 15.0.
Desirably, it is in the range of 00. Mw is 20,000
If it exceeds 30, it tends to be difficult to apply the resist composition of the present invention uniformly to the wafer, and further, the developability and sensitivity tend to decrease, and if Mw is less than 3,000, the heat resistance tends to decrease. .

In order to obtain a resin (A) having a high Mw, for example, the resin (A) recovered after completion of the polycondensation is treated with propylene glycol monomethyl ether acetate,
-Methyl methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-methoxypropionate, ethyl ethoxypropionate, ethyl cellosolve acetate,
After dissolving in a good solvent such as dioxane, methanol, ethyl acetate, butyl acetate, methyl isobutyl ketone, water, n
A poor solvent such as hexane and n-heptane may be mixed, and then a resin solution layer to be separated may be separated to recover a high molecular weight resin (A).

As means for producing the resin (A) for satisfying X / Y ≧ 2.0, (1) the ratio of the phenols used is appropriately selected. (2) A phenol having higher reactivity than p-cresol is appropriately selected. (3) The catalyst to be used is appropriately selected. (4) Phenols other than p-cresol are reacted at the beginning of the reaction, and the reaction is carried out while gradually adding p-cresol. And the like, and these can be combined as necessary. By these means, a resin (A) containing a large amount of p-cresol bound to the terminal can be obtained, and X / Y ≧ 2.0 can be satisfied. As long as this relationship is maintained, the resin (A) can be used alone or in combination of two or more.

[0016] In dissolution promoter present invention, for the purpose of promoting the alkali solubility of the resin (A), the low molecular weight phenolic compound (hereinafter,
It is referred to as "dissolution promoter." ) Can be added. As the dissolution promoter, a phenol compound having 2 to 5 benzene rings is suitable, and for example, the following formulas (1-1) to (1)
-9).

[0017]

Embedded image

In the above formulas (1-1) to (1-9),
a, b and c are each a number from 0 to 3 (provided that
Exclude when both are 0. ), X, y and z are each a number from 0 to 3, and a + x ≦ 5, b + y ≦ 5
And c + z ≦ 5 (however, (1-3) and (1-4)
B + y ≦ 4. ).

The amount of such a dissolution accelerator is usually not more than 50 parts by weight per 100 parts by weight of the resin (A).

Quinonediazidesulfonic acid ester compound The quinonediazidesulfonic acid ester compound used in the present invention includes 1,2-benzoquinonediazide-4-sulfonic acid ester of polyhydroxy compound and 1,2-
Naphthoquinonediazide-4-sulfonic acid ester, 1,
Examples thereof include 2-naphthoquinonediazide-5-sulfonic acid ester and 1,2-naphthoquinonediazide-6-sulfonic acid ester. Among these, 1,2-naphthoquinonediazide-4-sulfonic acid ester, 1,2
-Naphthoquinonediazide-5-sulfonic acid ester is preferred.

The quinonediazidesulfonic acid ester compound can be obtained, for example, by reacting a polyhydroxy compound with quinonediazidosulfonyl chloride in the presence of a basic catalyst. Usually, the ratio (average esterification ratio) of quinonediazidesulfonic acid ester to all hydroxyl groups of the polyhydroxy compound is 20% or more and 100% or less, and preferably 40% or more and 95% or less. If the average esterification rate is too low, it is difficult to form a pattern, and if it is too high, sensitivity may be reduced.

Here, the polyhydroxy compound to be used is not particularly limited, but specific examples include a compound represented by the following formula.

[0023]

Embedded image

[0024] In the formula, X ₁ to X ₁₅ are the same or different from each other, respectively, a hydrogen atom, an alkyl group of C ₁ ~C _4, C ₁
A C ₄ to C ₄ alkoxy group, a C _{6 to} C ₁₀ aryl group or a hydroxyl group. However, in each combination of X _{1 to} X ₅ and X _{6 to} X ₁₀ , at least one is a hydroxyl group. Y ₁ is a hydrogen atom or a C ₁ -C ₄ alkyl group.

[0025]

Embedded image

In the formula, X _{16 to} X ₃₀ are the same as X _{1 to} X ₁₅ described above. However, X _{16 to} X ₂₀ , X _{21 to} X ₂₅ and X ₂₆ to
At least one in each combination of X ₃₀ is a hydroxyl group. Y _{2 to} Y ₄ are the same or different from each other, and are a hydrogen atom or a C _{1 to} C ₄ alkyl group.

[0027]

Embedded image

In the formula, X _{31 to} X ₄₄ are the same as X _{1 to} X ₁₅ described above. However, at least one of X _{31 to} X ₃₅ is a hydroxyl group. Y _{5 to} Y ₈ are the same or different from each other, and are a hydrogen atom or a C _{1 to} C ₄ alkyl group.

[0029]

Embedded image

In the formula, X _{45 to} X ₅₈ are the same as or different from each other, and represent a hydrogen atom, a halogen atom, a C ₁ -C ₄ alkyl group, a C ₁ -C ₄ alkoxy group, a C ₅ -C ₇ It is a cycloalkyl group or a hydroxyl group. However, in each combination of X _{45 to} X ₄₈ and X _{49 to} X ₅₃ , at least 1
One is a hydroxyl group. Y ₉ and Y ₁₀ are the same or different from each other, and are a hydrogen atom, a C ₁ -C ₄ alkyl group or a C ₅ -C ₇ cycloalkyl group.

[0031]

Embedded image

In the formula, X _{59 to} X ₈₀ are the same as X _{45 to} X ₅₈ described above. However, X _{59 to} X ₆₃ , X _{64 to} X ₆₇ , X _{72 to} X ₇₅
And at least one of each combination of X _{76 to} X ₈₀ is a hydroxyl group. Y _{11 to} Y ₁₈ are the same or different from each other, and are a hydrogen atom or a C _{1 to} C ₄ alkyl group.

In the composition of the present invention, the quinonediazide sulfonic acid ester compound is a resin (A) 100
It is preferable to use 5 to 60 parts by weight, particularly 10 to 50 parts by weight, per part by weight. The quinonediazidesulfonic acid ester compounds can be used alone or in combination of two or more. The total weight of the 1,2-quinonediazidosulfonyl residues in the composition of the present invention is preferably 5 to 50% by weight, more preferably 10 to 30% by weight, based on the total solid content of the composition. It is adjusted to be.

Various Compounding Agents The composition of the present invention may optionally contain additives such as surfactants. The surfactant is compounded for improving the coating property and the developing property of the composition.
Examples of such a surfactant include polyoxyethylene lauryl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyethylene glycol dilaurate, polyethylene glycol distearate, and Megafax F
171, F172, F173, F471, R-07, R
-08 (trade name, manufactured by Dainippon Ink Co., Ltd.), Florard FC
430, FC431 (trade name, manufactured by Sumitomo 3M Limited),
Asahi Guard AG710, Surflon S-382, SC
-101, SC-102, SC-103, SC-10
4, SC-105, SC-106 (trade name, manufactured by Asahi Glass Co., Ltd.), KP341 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, No. 95 (trade name, manufactured by Kyoeisha Yushi Kagaku Kogyo) NBX-7, NBX-8, NBX-15
(Trade name, manufactured by Neos Corporation).

The amount of these surfactants is preferably 2 parts by weight or less per 100 parts by weight of the solid content of the composition excluding various components. Further, in the composition of the present invention, in order to visualize the latent image of the radiation-irradiated portion of the resist, and to reduce the influence of halation upon irradiation, a dye or pigment can be added, and the adhesiveness is improved. For this purpose, an adhesion aid may be added. Further, if necessary, a storage stabilizer, an antifoaming agent and the like can be added.

Solvent The composition of the present invention comprises a solid content such as the resin (A) described above,
For example, it is prepared by dissolving in a solvent so as to have a solid concentration of 20 to 40% by weight and filtering through a filter having a pore size of about 0.2 μm. As the solvent used at this time, for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, propylene Glycol monopropyl ether acetate, toluene, xylene, methyl ethyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, cyclohexane, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate,
Ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, 3
-Ethyl methoxypropionate, ethyl acetate, butyl acetate, methyl pluvate, ethyl pyruvate and the like. Further, N-methylformamide, N, N
-Dimethylformamide, N-methylformanilide,
N-methylacetamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, benzylethylether, dihexylether, acetonylacetone, isophorone, caproic acid, caprylic acid, 1
Add a high boiling point solvent such as -octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, ethylene glycol monophenyl ether acetate, etc. Can also. These solvents are used alone or in combination of two or more.

The composition of the present invention prepared as a solution for forming a resist film is applied to a silicon wafer or a wafer coated with aluminum or the like, for example, by spin coating, casting coating, roll coating, or the like. Next, a resist film is formed by pre-baking the resist film, and the resist film is irradiated with radiation so as to form a desired resist pattern, and is developed with a developer to form a pattern. As the radiation used at this time, ultraviolet rays such as g-rays and i-rays are preferably used, and various radiations such as charged ultraviolet rays such as far ultraviolet rays such as excimer laser, X-rays such as synchrotron radiation, and electron beams are used. You can also. Further, the composition of the present invention forms a resist film, performs pre-baking and radiation irradiation, performs an operation of heating at 70 to 140 ° C. (hereinafter, referred to as “post-baking”), and then develops. Thereby, the effect of the present invention can be further improved.

As the developer used for the resist film, for example, sodium hydroxide, calcium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate,
Aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline, pyrrole, piperidine, The concentration of an alkaline compound such as 1,8-diazabicyclo (5.4.0) -7-undecene, 1,5-diazabicyclo- (4.3.0) -5-nonane is 1 to 10% by weight, for example. As described above, an alkaline aqueous solution dissolved in water is used. Also,
In the developer, a water-soluble organic solvent, for example, methanol,
Alcohols such as ethanol and a surfactant may be appropriately added and used. In addition, when using a developer composed of such an alkaline aqueous solution, generally,
After development, washing with water is preferred.

[0039]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited by these examples. The measurement of Mw, pyrolysis gas chromatographic analysis, and evaluation of the resist in the examples were performed by the following methods. Mw: Tosoh GPC column (G2,000H _XL 2
This, G3,000H _XL 1 present, using G4,000H _XL 1 present), flow rate 1.0 ml / min, eluent tetrahydrofuran, analytical conditions of column temperature 40 ° C., gel permeation chromatography of a monodisperse polystyrene as the standard It was measured by a graph method.

Pyrolysis chromatographic analysis: Curie point type pyrolyzer JHP-3S manufactured by Nippon Kagaku Kogyo Co., Ltd. was used as a pyrolyzer, with a pyrolysis temperature of 670 ° C., a thermal analysis time of 5 seconds, and a sample amount of 0.5 ± 0.5. The resin was thermally decomposed under the condition of 05 mg, and α-DEX120 manufactured by Spelco (USA) was used.
(Medium-polar silicone phase [SPB-35, poly (3) having an inner diameter of 0.25 mm, a length of 30 m, a film thickness of 0.25 μm, and permethylated α-cyclodextrin chemically bonded to the inner wall of the column.
5% diphenyl-65% dimethylsiloxane)]
Weight% capillary column) was used as the separation column, and the helium flow rate was 1.0 ml / min, and the column temperature was 130.
C. to 240.degree. C. (heated at 3.degree. C./min) (gas chromatograph: Hewlett-Packard Company, HP-58)
P-cresol and 2,4-dimethylphenol in the decomposition product of the resin were measured with a Model 90, detector: flame ion detector.

Sensitivity: Nikon NSR-1505i9
The exposure time was changed using a C reduction projection exposure machine (numerical aperture of lens: 0.57), exposure was performed using i-rays having a wavelength of 365 nm, and then a 2.38% by weight aqueous solution of tetramethylammonium hydroxide was used as a developer. Use, 6 at 25 ° C
After developing for 0 second, rinsing with water and drying, a positive resist pattern was formed on the wafer. At that time, 0.4μ
An exposure time (hereinafter, referred to as an “optimum exposure time”) for forming a line-and-space pattern (1L1S) of m in a one-to-one width was determined.

Resolution: The dimension of the smallest resist pattern developed when exposed at the optimum exposure time was measured. Focus tolerance: A line-and-space pattern (1L1S) having a line width of 0.35 μm is observed using a scanning electron microscope, and the pattern size to be resolved is within ± 10% of the mask design size, and The ratio of the thickness after development to the thickness of the film before development of the resist pattern (hereinafter, referred to as
It is called "residual film ratio". ) Is 90% or more, the focus tolerance was evaluated based on the fluctuation width of the focus. The larger the amplitude, the better the focus tolerance.

Synthesis Example 1 m-cresol 64.9 g (0.6 mol) 37% by weight formaldehyde aqueous solution 50.3 g (formaldehyde 0.62 mol) oxalic acid dihydrate in a flask equipped with a condenser, a stirrer and a thermometer After charging 1.62 g (0.01 mol) of the product, the flask was immersed in an oil bath, and polycondensation was carried out for 6 hours with stirring while refluxing the reaction solution. Then, the temperature of the oil bath was raised to 180 ° C. over 4 hours, and then the pressure in the flask was reduced to 30 to 50 mmHg.
Remove volatiles, cool the molten resin to room temperature,
An oligomer having Mw = 4,500 was obtained. Next, 43.4 g (0.4 mol) of p-cresol 20.3 g (0.25 mol of formaldehyde) 37% by weight aqueous formaldehyde solution 1.90 g (0.01 mol) of p-toluenesulfonic acid 142 g of propylene glycol monomethyl ether were added. The flask was immersed in an oil bath, and polycondensation was performed for 2 hours with stirring while refluxing the reaction solution. Next, the temperature of the oil bath was raised to 180 ° C. over 4 hours, and then the pressure in the flask was reduced to 30 to 50 mmHg to remove volatile components and cool the molten resin (A) to room temperature. And collected. To this resin, 1.1 times the weight of methanol and 0.75 times the amount of water were added, and the mixture was stirred and allowed to stand. Then 2
The lower layer separated into layers was taken out, concentrated and dried to recover the resin (A). This resin (Mw = 8,500) is referred to as a resin (A1). Table 1 shows the result of the pyrolysis gas chromatography analysis of the resin (A1).

Synthesis Example 2 m-cresol 54.1 g (0.5 mol) 2,3-xylenol 24.4 g (0.2 mol) 37% by weight formaldehyde aqueous solution 53.6 g (formaldehyde 0.66 mol) Potassium hydroxide The same operation as in Synthesis Example 1 was carried out except that the amount was changed to 1.12 g (0.02 mol), whereby an oligomer having Mw of 4,700 was obtained. Next, p-cresol 32.4 g (0.3 mol) 37% by weight aqueous formaldehyde solution 17.0 g (formaldehyde 0.21 mol) potassium hydroxide 11.2 g (0.2 mol) propylene glycol monomethyl ether 142 g The same operation as in Synthesis Example 1 was performed to obtain a resin. This resin (Mw = 8,200) is referred to as a resin (A2). Table 1 shows the results of the pyrolysis gas chromatography analysis of the resin (A2).

Synthesis Example 3 m-cresol 64.9 g (0.6 mol) 3,5-xylenol 12.2 g (0.1 mol) 37% by weight aqueous formaldehyde solution 52.7 g (formaldehyde 0.65 mol) potassium hydroxide The same operation as in Synthesis Example 1 was carried out except that the amount was changed to 1.12 g (0.02 mol), to obtain an oligomer having Mw of 4,500. Next, p-cresol 32.4 g (0.3 mol) 37 wt% formaldehyde aqueous solution 21.1 g (formaldehyde 0.26 mol) p-toluenesulfonic acid 5.70 g (0.03 mol) propylene glycol monomethyl ether 142 g Was performed in the same manner as in Synthesis Example 1 to obtain a resin. This resin (Mw = 8,400) is referred to as a resin (A3). Table 1 shows the results of the pyrolysis gas chromatography analysis of the resin (A3).

Synthesis Example 4 A flask equipped with a condenser, a stirrer and a thermometer was charged with 32.4 g (0.4 mol) of p-cresol 64.9 g (0.6 mol) of m-cresol 71.4 g of a 37% by weight aqueous solution of formaldehyde (Formaldehyde 0.88 mol) After charging 1.26 g (0.01 mol) of oxalic acid dihydrate, the flask was immersed in an oil bath, and polycondensation was carried out for 4 hours with stirring while refluxing the reaction solution. went. Next, the temperature of the oil bath was raised to 180 ° C. over 3 hours, and then the pressure in the flask was reduced to 30 to 50 mmHg.
Volatiles were removed and the molten resin was cooled to room temperature and collected. After dissolving this resin in ethyl acetate so that the resin component becomes 30% by weight, 1.2 times the amount of methanol and 0.9 times the amount of water of the solution were added, and the mixture was stirred and left to stand. Next, the lower layer separated into two layers is taken out and concentrated,
The resin (a) was recovered by drying. This resin (Mw = 8,
200) is referred to as a resin (a1). Table 1 shows the result of the pyrolysis gas chromatography analysis of the resin (a1).

[0047]

[Table 1]

Examples 1 to 3 and Comparative Example 1 Components shown in Table 2 containing the resins (A) and (a) synthesized in each synthesis example, a quinonediazide compound, and if necessary, a dissolution promoter and a solvent. After mixing at a uniform ratio to obtain a uniform solution, the solution was filtered through a membrane filter having a pore size of 0.2 μm to prepare a solution of the resist composition shown in Table 2 (parts are based on parts by weight).

[0049]

[Table 2]

Here, the quinonediazide compound used,
The dissolution promoter and the solvent are as shown in Table 3 below.

[0051]

[Table 3]

Dissolution promoter (C1) 1,1-bis (4-hydroxyphenyl) -1
-Phenylethane (C2) 1,1-bis (2,5-dimethyl-4-hydroxyphenyl) -2-hydroxyphenylmethane solvent (α) ethyl 2-hydroxypropionate (β) ethyl 3-ethoxypropionate (γ ) Methyl-n-amyl ketone

Next, a solution of each resist composition was applied on a silicon wafer using a spinner,
Preliminary baking was performed for 2 minutes on a hot plate maintained at 100 ° C. (Examples 1 and 2 and Comparative Example 1) or 100 ° C. (Example 3) to form a 1.1 μm-thick resist film.
After exposing this resist film through a mask pattern,
Post-exposure baking was performed for 1 minute on a hot plate maintained at 10 ° C. Next, development, washing and drying were performed to form a resist pattern. Based on the results of the obtained resist patterns, the results of each resist were performed. Table 4 shows the evaluation results.

[0054]

[Table 4]

As shown in Examples 1 to 3 in Table 4, the resist compositions of the present invention were particularly excellent in focus tolerance and also excellent in sensitivity and resolution.

[0056]

The radiation-sensitive resin composition of the present invention is particularly excellent in focus tolerance and sensitivity and resolution. Therefore, the radiation-sensitive resin composition of the present invention is extremely useful as a positive resist for producing a highly integrated circuit, which will be further integrated in the future.

Claims (1)

[Claims] 1. A radiation-sensitive resin composition containing an alkali-soluble phenol resin and a quinonediazide compound, wherein the alkali-soluble phenol resin is a condensate of a phenol and an aldehyde containing p-cresol as an essential component, and The alkali-soluble phenol resin is detected as a pyrolysis product when measured at a pyrolysis temperature of 670 ° C. by pyrolysis gas chromatography using a capillary column having a silicone phase containing permethylated α-cyclodextrin on the inner surface. -A radiation-sensitive resin composition, characterized in that there is a relationship of X / Y ≧ 2.0 between the peak area value X of cresol and the peak area value Y of 2,4-dimethylphenol.