JP2813033B2 - Positive photosensitive resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention is suitably used as a resist for ultrafine processing in the production of a novel positive photoresist composition, more specifically, in the manufacture of semiconductor devices such as ICs and LSIs. The present invention relates to a positive-type photosensitive resin composition capable of forming a resist pattern having high sensitivity, excellent image contrast, excellent cross-sectional shape of a pattern, and particularly excellent heat resistance.

Conventional technology Conventionally, in the process of manufacturing semiconductor devices such as ICs and LSIs, a mask in which a thin film of a photoresist composition is formed on a silicon wafer as fine processing by photoetching, and the pattern of the semiconductor device is drawn on it A method is employed in which a pattern is transferred by ultraviolet irradiation or the like and then developed, and the silicon wafer is etched using the resist pattern thus obtained as a protective film. As the photoresist composition used in this method, a quinone diamide group-containing compound, particularly an aromatic polyhydroxy compound, naphthoquinone-is added to an alkali-soluble novolak resin for forming a film.
It is known that a compound containing 1,2-diazidesulfonic acid ester as a photosensitive component is suitable.

By the way, as the above-mentioned aromatic polyhydroxy compound, in particular, from among gallic esters and polyhydroxybenzophenones having a large hydroxyl group content per unit molecule,
Usually, it is usually appropriately selected, and many naphthoquinone-1,2-diazidosulfonic acid esters have been proposed so far (for example, U.S. Pat.
No. 046,118, No. 3,106,465, No. 3,148,
No. 983, JP-B-37-18015, JP-B-62-2845
No. 7 publication).

However, a positive photoresist composition using these polyhydroxybenzophenones, naphthoquinone-1,2-diazidesulfonic acid ester, has a sensitivity and an image to respond to ultra-fine processing in the field of semiconductor device manufacturing in recent years. Contrast, cross-sectional shape and heat resistance do not always have sufficiently satisfactory characteristics.

On the other hand, instead of naphthoquinone-1,2-diazidesulfonic acid ester of polyhydroxybenzophenones, a specific tris (hydroxyphenyl) methane compound naphthoquinone-1,2-diazidosulfonic acid ester is used as a photosensitive component. By doing so, a positive photoresist composition having characteristics suitable for ultrafine processing has also been proposed (JP-A-1-189644). However, this positive photoresist composition also does not necessarily have sufficient practical improvement in terms of heat resistance of the resist pattern obtained therefrom, and when prepared as a coating solution,
There is a problem that photosensitive components are easily precipitated and storage stability is poor.

Problem to be Solved by the Invention Under such circumstances, the present invention has a sufficiently satisfactory sensitivity as a positive photoresist composition used for ultrafine processing in the manufacture of semiconductor devices, The object of the present invention is to provide a material having excellent image contrast and cross-sectional shape, particularly excellent heat resistance and excellent storage stability, and having extremely high practicality.

Means for Solving the Problems The present inventors have intensively studied to develop a positive photoresist composition having the above-mentioned excellent characteristics, and as a result, the alkali-soluble novolak-type resin has a photosensitive composition comprising a special compound. It has been found that the object can be achieved by blending tris (hydroxyphenyl) methane or a methyl-substituted product thereof with the component, and the present invention has been completed based on this finding.

That is, the present invention relates to an alkali-soluble novolak resin, and a general formula (In the formula, at least one of D ¹ , D ² and D ³ is a naphthoquinone-1,2-diazidosulfonyl group and the rest is a hydrogen atom, and l, m and n are 0 or 1 to 1. With respect to 100 parts by weight of a mixture having a weight ratio of 1: 1 to 6: 1 with at least one compound selected from the compounds represented by the following formula: wherein tris (hydroxyphenyl) methane or its methyl-substituted product is used. The present invention provides a positive photosensitive resin composition comprising 3.8 to 25 parts by weight of at least one selected from the group consisting of:

 Next, the configuration of the present invention will be described in detail.

In the composition of the present invention, it is necessary to use at least one compound represented by the above general formula (I) or (II) as a photosensitive component. When used as a photosensitive component of a positive photoresist composition, it has high sensitivity and high image contrast because it dissolves well in solvents commonly used when used, and has good compatibility with the alkali-soluble novolak resin as a film-forming substance. The composition has excellent cross-sectional shape, storage stability and heat resistance.

These compounds have, for example, the general formula (Wherein l, m and n have the same meanings as described above), a naphthoquinone-1,2-diazidosulfonyl halide is condensed with tris (hydroxyphenyl) methane represented by Can be produced by This condensation reaction is carried out in an inert solvent such as dioxane in the presence of a basic condensing agent such as triethanolamine, alkali carbonate or alkali hydrogen carbonate.

Examples of the starting compound represented by the general formula (III) include tris (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) -3-hydroxyphenylmethane, and bis (4-hydroxy-2-methylphenyl)
-3-hydroxyphenylmethane, bis (4-hydroxy-2-methylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3-hydroxyphenylmethane, bis (4-hydroxy -2,5-dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4
-Hydroxy-3,5-dimethylphenyl) -3-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-2,3,5-trimethyl Phenyl)-
2-hydroxyphenylmethane, bis (4-hydroxyphenyl) -4-hydroxy-3-methylphenylmethane, bis (4-hydroxy-2-methylphenyl) -4
-Hydroxy-3,5-dimethylphenylmethane and the like, and particularly preferred starting compounds for improving the heat resistance of the composition of the present invention include compounds of the general formula (In the formula, at least one of D ¹ , D ² and D ³ is a naphthoquinone-1,2-diazidosulfonyl group and the rest is a hydrogen atom, and l ′, m ′ and n ′ are 0 , 1 or 2), for example, bis (4-hydroxy-2)
-Methylphenyl) -3-hydroxyphenylmethane,
Bis (4-hydroxy-2-methylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-2,5
-Dimethylphenyl) -3-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl)
-4-hydroxyphenylmethane and bis (4-hydroxy-2,3,5-trimethylphenyl) -2-hydroxyphenylmethane.

Examples of the raw material compound represented by the general formula (IV) include tris (2-hydroxyphenyl) methane,
Bis (2-hydroxyphenyl) -3-hydroxyphenylmethane, bis (2-hydroxyphenyl) -4-hydroxyphenylmethane, bis (2-hydroxy-4-
Methylphenyl) -2-hydroxyphenylmethane, bis (2-hydroxy-4-methylphenyl) -4-hydroxyphenylmethane, bis (2-hydroxy-4,6-
Dimethylphenyl) -2-hydroxyphenylmethane,
Bis (2-hydroxy-4,6-dimethylphenyl) -4
-Hydroxyphenylmethane, bis (2-hydroxy-
3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (2-hydroxy-4,6-dimethylphenyl) -2-hydroxy-4-methylphenylmethane, bis (2-hydroxy-4-methylphenyl)- 2-hydroxy-3,4,5-trimethylphenylmethane, bis (2
-Hydroxy-3,5-dimethylphenyl) -4-hydroxy-2,3,5-trimethylphenylmethane and the like.

On the other hand, naphthoquinone-1,2-diazidosulfonyl halide to be reacted with these tris (hydroxyphenyl) methanes includes naphthoquinone-1,2-diazide-
4-sulfonyl chloride, naphthoquinone-1,2-diazide-5-sulfonyl chloride or the corresponding bromide are preferred.

The photosensitive component of the present invention may be one in which all three hydroxyl groups in the above tris (hydroxyphenyl) methane are esterified, or one in which one or two of them are esterified. . These photosensitive components may be used alone or in combination of two or more.

Further, if desired, other quinonediazide group-containing compounds, such as orthobenzoquinonediazide, orthonaphthoquinonediazide, orthoanthraquinonediazide or orthonaphthoquinonediazide, or a sulfonyl chloride such as orthonaphthoquinonediazide and a hydroxyl group or an amino group, as long as the object of the present invention is not impaired. Compounds such as phenol, p-methoxyphenol, dimethylphenol, hydroquinone, bisphenol A, naphthol, pyrocatechol, pyrogallol,
Polyhydroxybenzophenone, pyrogallol monomethyl ether, pyrogallol-1,3-dimethyl ether,
Gallic acid, a reaction product with esterified or etherified gallic acid, aniline, p-aminodiphenylamine, etc., leaving a part of the hydroxyl group can be used in combination.

Next, in the composition of the present invention, in order to further improve the sensitivity, it is necessary to use tris (hydroxyphenyl) methane or a methyl-substituted product thereof in combination. Examples of such a compound include tris (hydroxyphenyl) methanes represented by the general formula (III) or (IV), for example, tris (2-hydroxyphenyl) methane, tris (4-hydroxyphenyl) methane, bis (4 -Hydroxy-3,5-dimethylphenyl) -3-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -4-hydroxyphenylmethane, bis (2-
Hydroxy-4,6-dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxyphenyl) -3-hydroxyphenylmethane, Bis (2-hydroxyphenyl) -4-hydroxyphenylmethane, bis (2-hydroxy-3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (2-hydroxy-4,6-dimethylphenyl) -2-
Hydroxyphenylmethane, bis (2-hydroxy-4,
6-dimethylphenyl) -2-hydroxy-4-methylphenylmethane and the like. These compounds may be used alone or in combination of two or more.

By using these compounds in combination, it is possible to obtain a practical positive-type photosensitive resin composition which is highly sensitized, has high sensitivity, and has a small dimensional change of the pattern with respect to the exposure amount.

Next, in the composition of the present invention, an alkali-soluble novolak resin is used as a film-forming substance. There is no particular limitation on the alkali-soluble novolak resin, and in a conventional positive photoresist composition, an alkali-soluble novolak resin commonly used as a film-forming substance, for example, an aromatic hydroxy compound such as phenol, cresol or xylenol, and formaldehyde Such aldehydes that are condensed in the presence of an acidic catalyst can be used.

In the composition of the present invention, as the alkali-soluble novolak-type resin, the weight average molecular weight obtained by cutting the low molecular weight region is 2,000 to 20,000, preferably 5,000 to 15,000 to obtain a composition having excellent heat resistance. Is advantageous.

The mixing ratio of the alkali-soluble novolak type resin and the photosensitive component represented by the general formula (I) or (II) is selected within a range of 1: 1 to 6: 1 by weight. If the amount of the photosensitive component used is smaller than this, an image faithful to the pattern cannot be obtained, the transferability is reduced, and if the used amount of the photosensitive component is larger than this, the uniformity of the formed resist film is reduced. And the resolution also deteriorates.

The tris (hydroxyphenyl) methane is used in an amount of 3.8 to 25 parts by weight per 100 parts by weight of the total amount of the alkali-soluble novolak resin and the compound represented by the general formula (I) or (II). Can be If the amount is less than this, the sensitizing effect is not sufficiently exhibited, and if the amount is more than this, the sensitizing effect cannot be obtained even though the amount used is increased, and it is not economically preferable. The optimum use amount is appropriately selected according to the type of the compound represented by the general formula (I) or (II).

The composition of the present invention is preferably used in the form of a solution obtained by dissolving a mixture of the above-described alkali-soluble novolak resin and a photosensitive component and tris (hydroxyphenyl) methane or a methyl-substituted product thereof in a suitable solvent.

Examples of such solvents include acetone, methyl ethyl ketone, cyclohexanone, ketones such as methyl isoamyl ketone; ethylene glycol, ethylene glycol monoacetate, diethylene glycol or monomethyl ether of diethylene glycol monoacetate,
Polyhydric alcohols such as monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof; cyclic ethers such as dioxane; and esters such as ethyl lactate, methyl acetate, ethyl acetate and butyl acetate. Can be mentioned. These may be used alone or as a mixture of two or more.

In the composition of the present invention, if necessary, a known sensitizer can be used together as long as the desired physical properties are not impaired. Examples of such a sensitizer include mercaptooxazole, mercaptobenzoxazole, mercaptooxazoline, mercaptobenzothiazole, benzoxazolinone, benzothiazolone, mercaptobenzimidazole, urazole, thiouracil, mercaptopyrimidine, imidazolone, tris- (4- (Hydroxyphenyl) ethane, 1,3-bis- (4-hydroxyphenyl) propane, 2,3,4-trihydroxybenzophenone, trisphenol TC (trade name, manufactured by Mitsui Petrochemical Co., Ltd.), and derivatives thereof, and the like. Can be. These sensitizers may be used alone or in combination of two or more, and the compounding amount is advantageously selected at 20% by weight or less based on the alkali-soluble novolak type resin. Even if it is added in an amount of more than% by weight, no improvement in the sensitizing effect is recognized for the amount, which is not preferable in practice.

The composition of the present invention may further contain, if necessary, compatible additives, for example, an additional resin, a plasticizer, a stabilizer, or a developed image for improving the performance of a resist film. For example, a commonly used colorant such as a coloring agent may be added.

One example of a preferred method of using the composition of the present invention is as follows. First, an alkali-soluble novolak resin, a photosensitive component, and tris (hydroxyphenyl) methane or a methyl-substituted product thereof are provided on a support such as a silicon wafer. A solution dissolved in an appropriate solvent as described above is applied by a spinner or the like, dried to form a photosensitive layer, and then a light source that emits ultraviolet light, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, an arc lamp, a xenon lamp Exposure is performed through a required mask pattern by using a mask or the like, or irradiation is performed while scanning an electron beam. Then, apply this to a developer, for example, 1 to
When immersed in a weak alkaline aqueous solution such as a 10% by weight aqueous solution of tetramethylammonium hydroxide, the exposed portion is dissolved and removed, and an image faithful to the mask pattern can be obtained.

Effects of the Invention The positive photosensitive resin composition of the present invention comprises a specific tris (hydroxyphenyl) methane compound, naphthoquinone-1,2-diazidosulfonic acid ester and tris (hydroxyphenyl) methane or a methyl tris (hydroxyphenyl) methane compound as a photosensitive component. It contains a substituent, and has a high sensitivity and a high residual film ratio of an unexposed portion, so that it has excellent cross-sectional shape and storage stability of an image contrast pattern, and has extremely excellent heat resistance as compared with the conventional one. It has excellent features such as formation of a resist pattern and high storage stability, and is particularly suitably used as a resist for ultrafine processing in the manufacture of semiconductor devices such as ICs and LSIs.

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 of the photoresist composition were determined as follows.

(1) Sensitivity; The sample was applied on a silicon wafer using a spinner, dried on a hot plate at 110 ° C for 90 seconds, and the film thickness was 1.3 µm.
m was obtained. This film is reduced projection exposure equipment NSR
After exposure using 0.155G4D (manufactured by Nikon Corporation) at an interval of 0.1 second to 0.02 second, development with an aqueous solution of 2.38% by weight of tetramethylammonium hydroxide for 1 minute, washing with water for 30 seconds and drying, for patterning, The required minimum exposure time was measured in milliseconds (ms) as sensitivity.

(2) Residual film ratio: The film thickness of the unexposed portion before and after development in the above sensitivity measurement was measured, and the residual film ratio was determined from the difference.

(3) Cross-sectional shape: The cross-sectional shape of the resist pattern having a width of 0.5 μm is observed with a microscope.
Those having a tapered side surface were regarded as defective.

(4) Heat resistance; resist pattern formed on silicon wafer
The pattern was baked on a hot plate at a temperature of 110 ° C., 120 ° C., 130 ° C., 140 ° C., and 150 ° C. for 5 minutes, and the presence or absence of deformation of the pattern was evaluated as heat resistance according to the following criteria.

○: No deformation △: Some deformation on the side, but no deformation in contact with silicon wafer ×: Deformation in contact with silicon wafer (5) Storage stability; Preparation The coating solution of the positive photoresist composition was allowed to stand at room temperature, and three months later, the presence or absence of a precipitate in the coating solution was examined.

Example 1 m-cresol and p-cresol in a weight ratio of 40:60
Of cresol novolak resin obtained by condensing in a conventional manner using an oxalic acid catalyst, fractionating the cresol novolak resin, cutting the low molecular weight region to obtain a cresol having a weight average molecular weight of 11,000. A novolak resin was obtained.

Next, the cresol novolak resin thus obtained
100 parts by weight, 30 parts by weight of an esterification reaction product of 1 mol of bis (4-hydroxy-3,5-dimethylphenyl) -2-hydroxyphenylmethane and 3 mol of naphthoquinone-1,2-diazido-5-sulfonyl chloride And Tris (4-
After dissolving 15 parts by weight of (hydroxyphenyl) methane (equivalent to 11.5 parts by weight per 100 parts by weight of the mixture of the alkali-soluble novolak resin and the photosensitive component) in 350 g of ethyl lactate, use a membrane filter having a pore size of 0.2 μm. And filtered to prepare a photosensitive resin composition. The physical properties of this product are shown in Table 2.

Examples 2 to 9 With respect to 100 parts by weight of various novolak resins shown in Table 1, various tris (hydroxyphenyl) compounds shown in Table 1 were used.
Various positive photosensitive resin compositions were prepared by mixing the condensation product of methane with naphthoquinone-1,2-diazidosulfonyl chloride and tris (hydroxyphenyl) methane in the proportions shown in Table 1. Table 2 shows the physical properties of these compositions.

Comparative Examples 1 to 5 Same cresol novolak resin used in Example 1
The photosensitive components shown in Table 1 and the sensitizer used in some cases were mixed in the amounts (parts by weight) shown in Table 1 with respect to 100 parts by weight to prepare a positive photosensitive resin composition. Table 2 shows the physical properties of these compositions.

The abbreviations in Table 1 mean the following compounds, and the amounts of the photosensitive components and the sensitizers indicate parts by weight per 100 parts by weight of the novolak resin.

Trisphenol TC; α, α ', manufactured by Mitsui Petrochemical Co., Ltd.
Trade name of α ″ -tris (4-hydroxyphenyl) -1,3,5-triisopropylbenzene NQS [4]; naphthoquinone-1,2-diazide-4-sulfonyl chloride NQS [5]; naphthoquinone-1,2 -Diazide-5-sulfonyl chloride

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shinto Saito 1065-2 Kamigo, Ebina-shi, Kanagawa Koraku Heights 201 (56) References JP-A-1-189644 (JP, A) JP-A-3-158856 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G03F ^7/ 00-7/16

Claims (2)

(57) [Claims] (1) an alkali-soluble novolak type resin, (In the formula, at least one of D ¹ , D ² and D ³ is a naphthoquinone-1,2-diazidosulfonyl group and the rest is a hydrogen atom, and l, m and n are 0 or 1 to 1. With respect to 100 parts by weight of a mixture having a weight ratio of 1: 1 to 6: 1 with at least one compound selected from the compounds represented by the following formula: wherein tris (hydroxyphenyl) methane or its methyl-substituted product is used. A positive photosensitive resin composition comprising 3.8 to 25 parts by weight of at least one selected from the group consisting of: 2. The photosensitive component of the general formula (In the formula, D ¹ , D ² and D ³ have at least one of them being a naphthoquinone-1,2-diazidosulfonyl group, the rest being hydrogen atoms, and l ′, m ′ and n ′ are 0. The positive photosensitive resin composition according to claim 1, which is at least one selected from compounds represented by the following formulas: