JP3434558B2 - Positive resist composition - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel positive resist composition, and more specifically, it is excellent in storage stability, coating property, and conformal property, which is preferably used in the production of electronic component materials, etc. The present invention relates to a positive resist composition which does not change and is excellent in safety.

[0002]

2. Description of the Related Art In the manufacture of electronic component materials such as semiconductor devices and liquid crystal display devices, a pattern transfer method by photolithography is used as a method for forming a pattern on a substrate. In this photolithography, a resist is applied on a substrate such as a silicon wafer using a spinner, dried, and then irradiated with an actinic ray through a mask and developed to transfer a mask pattern onto the substrate, followed by etching. Is. The resist used as the mask for this etching was initially of the negative type, but the negative type resist is currently used because of the problem of resolution limit due to expansion in the developing solution and mask damage in contact exposure. A positive resist having excellent image quality is often used.

By the way, in recent years, silicon wafers and glass substrates have become large in size, and when coating a resist on a substrate, it is desired that the coating film have excellent uniformity, and that a substrate having irregularities on the surface be used. When forming a coating film, the smaller the film thickness difference between the coating film formed on the concave portion and the coating film formed on the convex portion, the better the resist pattern formed. Therefore, it is required that the coating film has a small difference in film thickness, that is, one that has excellent conformality, and that the impact of chemicals on the environment and the human body is a major problem, and it does not adversely affect the environment and There is a strong demand for a resist that does not harm the above, and various studies have been conducted on the resist solvent.

Conventionally, ethylene glycol monoethyl ether acetate has been generally used as a solvent for positive photoresists. In recent years, however, these cellosolve-based solvents have been reported to have toxicity, and environmental concentration regulations have been strengthened. It is becoming impossible. In addition, ethylene glycol monoethyl ether acetate has a drawback that the solubility of the photosensitizer is insufficient. For this reason, cyclopentanone has been proposed as having improved solubility (Japanese Patent Laid-Open No. 59-155838). However, this compound has a drawback that it decomposes a photosensitizer composed of a quinonediazide group-containing compound and causes a change in sensitivity with time. Alkyl monooxymonocarboxylates have also been proposed (Japanese Patent Application Laid-Open No. 62-123444), but they have too high hygroscopicity to cause precipitation of a photosensitizer, resulting in poor storage stability, and coating property. , Conformality is not enough. Further, a combination of a cyclic ketone and an alcohol has been proposed (US Pat. No. 4,526,856), but also in this case, the photosensitizer is likely to be deposited and the storage stability is poor. In addition, propylene glycol monoalkyl ether acetate has been proposed (Japanese Patent Laid-Open No. 61-783).
No. 7), this also has a problem that the compatibility with the photosensitizer is insufficient, the storage stability is poor, and the sensitivity changes with time.

[0005]

Thus, conventional positive photoresist compositions, particularly those containing a high degree of esterification of naphthoquinone-1,2-diazide sulfonic acid ester of polyhydroxybenzophenone as a photosensitizer For photoresists, there is no solvent that is sufficiently satisfactory in terms of compatibility and storage stability, and there are various problems in terms of safety. The solvent has been long-awaited.

Under the circumstances described above, the present invention provides a positive resist composition which is excellent in storage stability, coating property, conformal property, does not change in sensitivity with time, and is excellent in safety. It was made for the purpose of providing.

[0007]

Means for Solving the Problems The present inventors have conducted earnest research on a solvent capable of achieving the above-mentioned object for a positive resist composition obtained by combining a photosensitive component comprising a quinonediazide group-containing compound with an alkali-soluble resin. As a result of stacking, when L (+) type alkyl α-oxypropionate is used as a solvent for photoresist, the solubility of the photosensitizer is higher than that of the conventional solvent and the precipitation of the photosensitizer does not occur, that is, storage stability is excellent. At the same time, it was found that a positive resist composition having excellent coating property and conformality, having no change in sensitivity with time, and having excellent safety was obtained, and based on this finding, the present invention was completed. .

That is, the present invention comprises (A) an alkali-soluble resin and (B) a quinonediazide group-containing compound.
(C) Positive resist composition prepared by dissolving L (+) type α-alkyl oxypropionate alone or in a mixed solvent with another organic solvent mainly containing L (+) type α-oxypropionate Is provided.

Examples of the alkali-soluble resin used as the component (A) in the composition of the present invention include novolac resins, acrylic resins, copolymers of styrene and acrylic acid, polymers of hydroxystyrene, polyvinylphenol, poly α. -Methyl vinylphenol and the like are mentioned, and among them, alkali-soluble novolac resin is particularly preferable. The alkali-soluble novolak resin is not particularly limited, and those conventionally used as film-forming substances in positive photoresist compositions, such as aromatic hydroxy compounds such as phenol, cresol, and xylenol, and aldehydes such as formaldehyde are used. Those condensed in the presence of an acidic catalyst are used. The alkali-soluble novolac resin has a weight average molecular weight of 2,000 to 20,000 with the low molecular weight region cut.
The range of 5000 to 15000 is preferable.

In the composition of the present invention, a quinonediazide group-containing compound is used as the photosensitive component of the component (B). As the compound, for example, a compound obtained by partially or completely amidating a sulfonic acid of a quinonediazide such as benzoquinonediazide, naphthoquinonediazide or anthraquinonediazide or a functional derivative thereof (such as sulfonic acid chloride) and a compound having an amino group, etc. Although a quinonediazide group-containing organic sulfonic acid ester compound is preferably used, an esterified product of the sulfonic acid and a polyhydroxy compound is preferably used. The ester compound may be a complete esterified product or a partial esterified product.

Examples of the quinonediazide group-containing organic sulfonic acid include naphthoquinone-1,2-diazide-5-sulfonic acid, naphthoquinone-1,2-diazide-4-sulfonic acid and naphthoquinone-1,2-diazide-6-sulfone. Examples thereof include naphthoquinone-1,2-diazide sulfonic acid such as acid, orthobenzoquinone diazide sulfonic acid, orthoanthraquinone diazide sulfonic acid.

The following compounds (a) to (f) are preferable as the polyhydroxy compound. (A) 2,3,4-trihydroxybenzophenone,
2,4,4'-trihydroxybenzophenone, 2,
4,6-trihydroxybenzophenone, 2,3,4
4'-tetrahydroxybenzophenone, 2,2 ',
4,4'-tetrahydroxybenzophenone, 2,
3 ', 4,4', 6-pentahydroxybenzophenone, 2,2 ', 3,4,4'-pentahydroxybenzophenone, 2,2', 3,4,5'-pentahydroxybenzophenone, 2,3 ' , 4,5,5'-Pentahydroxybenzophenone, 2,3,3 ', 4,4', 5 '
-Polyhydroxybenzophenones such as hexahydroxybenzophenone.

(B) 1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene and other general formula (I)

[Chemical 1] (R ^{1 to} R ⁶ in the formula are hydrogen atom, halogen atom, hydroxyl group,
An alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms, R ⁷ and R ⁸ are a hydrogen atom, a halogen atom or a carbon number 1
To 4 alkyl groups, R ^{9 to} R ¹¹ are hydrogen atoms or 1 carbon atoms.
Is an alkyl group of 4).

(C) Tris (4-hydroxyphenyl)
Methane, bis (4-hydroxy-3,5-dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3-hydroxyphenylmethane, bis (4-hydroxy-3,3 5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -4
-Hydroxyphenylmethane, bis (4-hydroxy-
2,5-dimethylphenyl) -3-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3 4-dihydroxyphenylmethane, bis (4-hydroxy-2,
5-dimethylphenyl) -3,4-dihydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -2,4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl)- Two
General formula (II) such as 4-dihydroxyphenylmethane and bis (4-hydroxyphenyl) -3-methoxy-4-hydroxyphenylmethane

[Chemical 2] (In the formula, R ¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ^{2 to} R ⁷ are hydrogen atoms, halogen atoms, and 1 to 4 carbon atoms.
An alkyl group or an alkoxy group having 1 to 4 carbon atoms, 1,
tris (hydroxyphenyl) methanes represented by m and n are integers of 1 to 3.

(D) bis (3-cyclohexyl-4-hydroxyphenyl) -3-hydroxyphenylmethane,
Bis (3-cyclohexyl-4-hydroxyphenyl)
-2-hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxyphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -2-hydroxyphenylmethane, bis (3 -Cyclohexyl-4-hydroxy-
6-methylphenyl) -3-hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxy-6-
Methylphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -3,4-dihydroxyphenylmethane, bis (3-cyclohexyl-6-hydroxyphenyl)-
3-hydroxyphenylmethane, bis (3-cyclohexyl-6-hydroxyphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl-6-hydroxyphenyl) -2-hydroxyphenylmethane, bis (3-cyclohexyl-6- Hydroxy-4-methylphenyl) -2-hydroxyphenylmethane, bis (3-
Cyclohexyl-6-hydroxy-4-methylphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl-6-hydroxy-4-methylphenyl)-
Bis (cyclohexylhydroxyphenyl) -hydroxyphenylmethanes such as 3,4-dihydroxyphenylmethane.

(E) 2- (2,3,4-trihydroxyphenyl) -2- (2 ', 3', 4'-trihydroxyphenyl) propane, 2- (2,4-dihydroxyphenyl) -2 -(2 ', 4'-dihydroxyphenyl) propane, 2- (4-hydroxyphenyl) -2- (4'
-Hydroxyphenyl) propane, bis (2,3,4-
[(Poly) hydroxyphenyl] alkanes such as trihydroxyphenyl) methane and bis (2,4-dihydroxyphenyl) methane.

(F) Phenol, p-methoxyphenol, dimethylphenol, hydroquinone, bisphenol A, naphthol, pyrocatechol, pyrogallol monomethyl ether, pyrogallol-1,3-dimethyl ether, gallic acid, partially esterified or partially etherified gallic acid Compounds with hydroxyl groups such as.

As the component (B), for the purpose of improving sensitivity, resolution, heat resistance, and depth of focus characteristics, in particular, the polyhydroxy compounds (a) to (f) and naphthoquinone-1,2- It is preferable to use an esterified product with diazidosulfonic acid in an appropriate combination according to the purpose.

In this case, particularly preferable polyhydroxy compound is 2,3,4-in the above-mentioned compound (a).
Trihydroxybenzophenone and 2,3,4,4′-tetrahydroxybenzophenone are among the compounds of the above (b), 1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis ( 4-hydroxyphenyl) ethyl] benzene is bis (4-hydroxy-3,5-dimethylphenyl) -in the compound of (c) above.
2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3,4-dihydroxyphenylmethane, bis ( 4-hydroxy-2,5-dimethylphenyl) -3,
4-dihydroxyphenylmethane and bis (4-hydroxyphenyl) -3-methoxy-4-hydroxyphenylmethane are bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -in the compound (d) above.
2-hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -3-hydroxyphenylmethane, bis (3-cyclohexyl-
4-hydroxy-6-methylphenyl) -4-hydroxyphenylmethane and bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -3,4-dihydroxyphenylmethane are among the compounds of (e) above. 2-
(2,3,4-trihydroxyphenyl) -2-
(2 ', 3', 4'-Trihydroxyphenyl) propane, 2- (2,4-dihydroxyphenyl) -2-
Examples include (2 ', 4'-dihydroxyphenyl) propane and bis (2,3,4-trihydroxyphenyl) methane.

The esterified product of the organic sulfonic acid containing a quinonediazide group in the component (B) is a polyhydroxy compound, particularly the polyhydroxybenzophenones, 1- [1- (4-hydroxyphenyl) isopropyl].
-4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene, the tris (hydroxyphenyl) methanes, the bis (cyclohexylhydroxyphenyl)
-Hydroxyphenylmethanes, the above [(poly) hydroxyphenyl] alkanes, and quinonediazide group-containing organic sulfonic acids, especially naphthoquinone-1,2-diazide-4-sulfonyl halide or naphthoquinone-1,2-
It can be produced by subjecting a diazido-5-sulfonyl halide to a condensation reaction to complete esterification or partial esterification. This condensation reaction is carried out in an organic solvent such as dioxane, N-methylpyrrolidone or dimethylacetamide in the presence of a basic condensing agent such as triethanolamine, alkali carbonate or alkali hydrogen carbonate.

The component (B) is a polyhydroxy compound, particularly 50% or more, preferably 60% or more, of naphthoquinone-based on the total moles of hydroxyl groups of the compounds (a) to (f). Ester products obtained by reacting 1,2-diazido-5-sulfonic acid chloride or naphthoquinone-1,2-diazide-4-sulfonic acid chloride (average esterification degree of 50% or more, preferably 60% or more) have particularly high resolution. It is preferable because it provides image quality.

In the composition of the present invention, the various quinonediazide group-containing compounds described above as the component (B) may be used alone or in combination of two or more kinds.

In the composition of the present invention, as the component (C), L (+) type α-oxypropionate is used alone, or L (+) type α-oxypropionate is mainly used. It is necessary to use a mixed solvent which is a combination of the above and other suitable organic solvents.

By the way, the alkyl α-oxypropionate has a chiral center to which a hydroxyl group, a hydrogen atom, a methyl group and an alkyl ester group are bonded, and the L (+) type and D
There is a (−) type optical isomer. Alkyl α-oxypropionate, which has been used as a solvent for photoresists, has been a racemic mixture in which the L (+) type and the D (−) type are mixed in the same amount. However, such a racemate is not sufficiently safe because it contains a D (-) form that is not metabolized in the animal body.

On the other hand, the L (+) type is metabolized in the body of animals and is also known as a natural component. Therefore, α consisting of the racemate that has been used so far
-L of the present invention in comparison to alkyl oxypropionate
(+) Type alkyl α-oxypropionate is highly safe. Moreover, the L (+) type alkyl α-oxypropionate is more excellent in solubility of the photosensitizer than the conventionally used resist solvent, and also when the positive resist solution using the same is stored, No precipitation occurs and storage stability is good. Further, with respect to the change in sensitivity with time, the rate of change in sensitivity is smaller and more stable than the conventionally used resist solvent.

The L (+) type α-oxypropionate used alone or as the main component in the component (C) includes L (+) type methyl α-oxypropionate and L (+) type α-oxy. Ethyl propionate, L
Examples thereof include propyl (+) type α-oxypropionate and butyl L (+) type α-oxypropionate, and among these, L (+) type ethyl α-oxypropionate is particularly preferable. In addition, these L (+) type α
The alkyl oxypropionates may be used alone or in combination of two or more.

When the above-mentioned mixed solvent is used as the component (C), the organic solvent used in combination with the L (+) type alkyl α-oxypropionate has the following properties such as solubility, storage stability and sensitivity with time. In addition, in order to further improve the coating property and the conformal property, (b) the temperature is 20 ° C.
An organic solvent having a viscosity of 1 centipoise or less is preferable.

The organic solvent having a viscosity of 1 centipoise or less at 20 ° C. of the component (b) is not particularly limited, and examples thereof include methyl acetate, ethyl acetate, propyl acetate,
Isopropyl acetate, butyl acetate, isobutyl acetate, methyl propionate, ethyl propionate, butyl propionate, acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, methyl isobutyl ketone, 2-heptanone, 4-heptanone, etc. Of these, butyl acetate is particularly preferable. These organic solvents may be used alone or in combination of two or more.

The organic solvent having a predetermined viscosity or less of the component (b) has a function of adjusting the viscosity of the positive resist solution,
It is possible to improve the uniformity and conformality of the coating film when applied on a substrate.

When the above-mentioned mixed solvent is used as the component (C), as an organic solvent used in combination with the L (+) type alkyl α-oxypropionate, in addition to the component (b), optionally ( C) A hydrocarbon-based organic solvent can be added. The hydrocarbon-based organic solvent of component (c) is preferably an aromatic hydrocarbon-based solvent such as xylene, which improves the uniformity and conformality of the coating film when coated on a substrate. You can

When the mixed organic solvent is used as the component (C) in the composition of the present invention, the content ratio of each solvent component is as follows in the two-component system of the component (a) and the component (b).
(A) Component 60 to 90% by weight and (B) Component 40 to 10
In the range of weight%, the (a) component, the (b) component, and the (c)
In the three-component system of components, (a) component 60 to 90% by weight,
It is preferable to select each of the component (b) in the range of 5 to 30% by weight and the component (c) in the range of 5 to 10% by weight because the desired effect can be obtained.

Component (A), (B) in the composition of the present invention
Regarding the blending ratio of the component and the component (C), it is preferable to select the blending amount of the component (B) in the range of 10 to 50% by weight, preferably 20 to 40% by weight based on the component (A). If the blending amount is too small, it is difficult to obtain an image faithful to the pattern and the transferability tends to be lowered, and if it is too large, the homogeneity of the resist film to be formed tends to be low and the resolution is low. The sensitivity tends to deteriorate.

The amount of the component (C) blended may be within a range that gives good coating properties and a coating film having a desired film thickness can be obtained. 5 for the total amount of
It is preferable to select in the range of 0 to 2000% by weight, preferably 100 to 1000% by weight. If the blending amount is too small, the viscosity becomes high and it becomes difficult to handle, and if it is too large, it takes time to adjust the coating amount and drying, and the workability tends to deteriorate.

The composition of the present invention may further contain compatible additives such as an additional resin, a plasticizer, a stabilizer for improving the performance of the resist film or a pattern obtained by development. A colorant for making it more visible, a sensitizer for further improving the sensitizing effect, and a commonly used one such as a contrast improving agent can be added and blended.

The composition of the present invention is mixed with the above-mentioned mixed organic solvent.
It is advantageous to dissolve the alkali-soluble resin, the quinonediazide group-containing compound, and the additional components to be blended, if necessary, in the required amounts and use them in the form of a solution.

About the preferred method of using the composition of the present invention 1
For example, first, on a substrate such as a silicon wafer,
A solution obtained by dissolving the alkali-soluble resin and the quinonediazide group-containing compound in the above-mentioned L (+) type alkyl α-oxypropionate or a mixed organic solvent thereof is applied with a spinner, a roll coater, etc., and dried to be exposed. Form a layer and then expose it through a required mask pattern using a light source that emits ultraviolet light, such as a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, an arc lamp, a xenon lamp, or a reduction projection exposure device. The irradiation is performed with an excimer laser or X-rays through a mask pattern, or while scanning with an electron beam. Next, when this is immersed in a developing solution, for example, an alkaline aqueous solution such as a 1-10 wt% tetramethylammonium hydroxide aqueous solution, the portion solubilized by exposure is selectively dissolved and removed, and an image faithful to the mask pattern is obtained. Can be obtained.

Such a pattern is not limited to semiconductor processing, but can be applied in the field of processing using lithography, such as LC.
The same excellent effect can be obtained for D, TAB, PCB, chemical milling, printing and the like. In particular, the composition of the present invention was not able to obtain a coating film excellent in uniformity with conventional organic solvents, and even when applied to a large substrate or a rectangular substrate, a highly uniform coating film can be easily obtained. It also has a practical effect of being excellent in conformality.

[0038]

EFFECT OF THE INVENTION The positive resist composition of the present invention contains, as a preparation solvent thereof, an L (+) type α-oxypropionate alone solvent or an L (+) type α-alkyl oxypropionate as a main component. By using a mixed solvent of an organic solvent, preferably an L (+) type α-oxypropionate, an organic solvent having a viscosity of 1 centipoise or less at a temperature of 20 ° C., and a hydrocarbon-based organic solvent optionally used, It is possible to form a coating film in which the solubility of the photosensitizer is high, the precipitation of the photosensitizer does not occur, that is, the storage stability is excellent, the coating property and the conformal property are excellent, and the sensitivity does not change with time. Moreover, since it is highly safe and does not adversely affect the environment or the human body, it is extremely effective in practice.

[0039]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

The physical properties in each example are obtained by the following methods. (1) Uniformity A positive resist composition coating solution is applied onto a 6-inch silicon wafer, TR8162-SR having a temperature and humidity control function.
(Manufactured by Tatsumo) was applied at 3000 rpm for 20 seconds and dried on a hot plate at 90 ° C. for 90 seconds to form a coating film. Film thickness measuring device (NANOSPEC / AFT MODEL21 manufactured by Nanometrics Co., Ltd.)
0), the film thickness at 50 points on the silicon wafer on which the coating film is formed is measured, and the standard deviation σ
I asked for (Å). The smaller the standard deviation σ, the smaller the variation in the film thickness.

(2) Storage stability A coating solution of the prepared positive resist composition was 0.2 μm.
After filtering through a membrane filter of No. 4, stored in a brown bottle at 40 ° C., the number of precipitates in the solution was measured every month from the time of preparation using a particle counter KL-20 (manufactured by Lion Corporation), and the particle counter was used. Was NG (the number of precipitates was too large to be measured).

(3) Change in sensitivity with time The sensitivity after storage of the prepared positive resist composition in a brown bottle under low temperature conditions (5 to 10 ° C.) for 3 months was A.
On the other hand, the sensitivity change rate is represented by [| B−A | / A] × 100, where the sensitivity after storage of this resist composition in a brown bottle at 40 ° C. for 3 months is B, and the sensitivity change rate is 0. Those within 2% were evaluated as ⊚, those exceeding 2% and 5% or less were evaluated as ○, those exceeding 5% and 8% or less were evaluated as Δ, and those exceeding 8% were evaluated as ×. In addition, since A is the case where it was stored under a low temperature condition, it is almost the same as the sensitivity at the time of preparing this resist composition.

(4) The coating solution of the conformal positive resist composition was applied onto a 6-inch silicon wafer on which a silicon oxide film pattern having a film thickness of 0.5 μm was formed in a line and space having a width of 2.0 μm.
It was applied with a spinner with a temperature and humidity adjustment function (Tatsumo TR8162-SR) so that the dry film thickness on a flat surface without a silicon oxide film pattern would be 1.5 μm.
A coating film is formed on the entire surface of the wafer by drying,
The difference between the film thickness of the coating film formed on the line portion and the film thickness of the coating film formed on the space portion is shown by the measured value obtained by the cross-sectional photograph by SEM (scanning electron microscope).

(5) Solubility of Photosensitizer A photosensitizer is dissolved in a resist solvent to prepare a 5% by weight solution of the photosensitizer, which is dissolved by shaking at room temperature.
B that melts when heated to 70 to 80 ° C and is dissolved by ultrasonic vibration while heating to 70 to 80 ° C, and ultrasonic vibration that heats to 70 to 80 ° C What did not dissolve was evaluated as D.

Example 1 2,3,4,4'-tetrahydroxybenzophenone 1
Mole of naphthoquinone-1,2-diazide-5-sulfonyl chloride (3 moles), 2 g of a product of an esterification reaction and 8 g of cresol novolac resin were added to 40 g of L (+)-type α-oxypropionate (purity 99%). It melt | dissolved and prepared the coating liquid of the positive resist composition. The physical properties of this coating solution were examined, and the results are shown in Table 1.

Example 2 Instead of L (+) type ethyl α-oxypropionate, L
(+) Type ethyl α-oxypropionate (purity 99%)
A coating liquid of the positive resist composition was prepared in the same manner as in Example 1 except that a mixed solvent of 32 g and 8 g of butyl acetate was used. The physical properties of this coating solution were examined, and the results are shown in Table 1.

Example 3 A positive resist composition coating solution was prepared in the same manner as in Example 2 except that 4 g of butyl acetate and 4 g of xylene were used instead of butyl acetate. Check the physical properties of this coating solution,
The results are shown in Table 1.

Example 4 L (+) type L-α-oxypropionate was replaced with L
(+) Type ethyl α-oxypropionate (purity 99%)
A coating solution of a positive resist composition was prepared in the same manner as in Example 1 except that a mixed solvent of 32 g and 8 g of methyl 3-methoxypropionate was used. The physical properties of this coating solution were examined, and the results are shown in Table 1.

Comparative Example 1 L (+)-type ethyl α-oxypropionate was replaced by L
A coating liquid of a positive resist composition was prepared in the same manner as in Example 1 except that a racemic mixture containing the same amount of (+) type and D (-) type was used. The physical properties of this coating solution were examined, and the results are shown in Table 1.

Comparative Example 2 A positive resist composition coating solution was prepared in the same manner as in Example 1 except that propylene glycol monomethyl ether acetate was used instead of L (+) type ethyl α-oxypropionate. The physical properties of this coating solution were examined, and the results are shown in Table 1.

Comparative Example 3 A positive resist composition coating solution was prepared in the same manner as in Example 1 except that cyclopentanone was used instead of the L (+) type ethyl α-oxypropionate. The physical properties of this coating solution were examined, and the results are shown in Table 1.

Reference Example Solubility of the photosensitizer used in Example 1 in the solvents used in Examples 1 to 4 and Comparative Examples 1 to 3 was examined, and the results are shown in Table 1.

[0053]

[Table 1]

─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Nobuo Tokutake 150 Nakamaruko, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Tokyo Ohka Kogyo Co., Ltd. (72) Hidekatsu Ohara 150, Nakamaruko, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Tokyo Ohka Kogyo Incorporated (72) Inventor Toshinasa Nakayama 150 Nakamaruko, Nakahara-ku, Kawasaki, Kanagawa Tokyo Ohka Kogyo Co., Ltd. (56) Reference JP-A-5-273750 (JP, A) JP-A-2-222955 (JP , A) JP 4-173880 (JP, A) JP 6-214383 (JP, A) JP 7-140647 (JP, A) JP 62-123444 (JP, A) JP 62-96091 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03F ^7/ 00-7/42

Claims (5)

(57) [Claims] 1. An (A) alkali-soluble resin and a (B) quinonediazide group-containing compound are (C) L (+) type α-
Alkyl oxypropionate alone solvent or L (+)
A positive resist composition obtained by dissolving a type α-alkyl oxypropionate in a mixed solvent with another organic solvent. 2. An alkali-soluble resin (A) and a quinonediazide group-containing compound (B) are added to (C) (a) L (+).
Mainly type α-oxypropionate alkyl, (b)
A positive resist composition obtained by dissolving in a mixed solvent with an organic solvent having a viscosity of 1 centipoise or less at a temperature of 20 ° C. 3. An alkali-soluble resin (A) and a quinonediazide group-containing compound (B) are added to (C) (a) L (+).
Mainly type α-oxypropionate alkyl, (b)
A positive resist composition obtained by dissolving in a mixed solvent of an organic solvent having a viscosity of 1 centipoise or less at a temperature of 20 ° C. and (c) a hydrocarbon organic solvent. 4. The positive resist composition according to claim 1, wherein the alkyl group of the L (+) type α-oxypropionate is one having 1 to 4 carbon atoms. 5. The positive resist composition according to claim 1, wherein the alkyl group is an ethyl group.