JP2801179B2 - Positive photosensitive resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a novel positive photosensitive resin composition, and more particularly, to a high-sensitivity photosensitive resin composition suitable for use as a photoresist for ultrafine processing in the production of semiconductor devices such as ICs and LSIs. The present invention relates to a positive photosensitive resin composition which has excellent image contrast and cross-sectional shape of a pattern and can form a resist pattern having particularly excellent heat resistance.

[0002]

2. Description of the Related Art Conventionally, in a process of manufacturing a semiconductor device such as an IC or an LSI, a thin film of a photoresist composition is formed on a silicon wafer as fine processing by a photoetching method, and a pattern of the semiconductor device is drawn thereon. A method is employed in which the mask 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 quinonediazide group-containing compound, particularly naphthoquinone-1,2-diazidesulfonic acid ester of an aromatic polyhydroxy compound, is added to an alkali-soluble novolak resin for forming a film. It is known that those blended as components are suitable.

The aromatic polyhydroxy compound is usually appropriately selected from gallic esters and polyhydroxybenzophenones having a large hydroxyl group content per unit molecule. Many naphthoquinone-1,2-diazidosulfonic acid esters have been proposed (for example, US Pat. Nos. 3,046,118 and 3,10).
No. 6,465, 3,148,983, JP-B-37-18015, JP-B-62-28.
457).

However, positive photoresist compositions using these naphthoquinone-1,2-diazidosulfonic acid esters of polyhydroxybenzophenones are:
The sensitivity, image contrast, cross-sectional shape, and heat resistance for responding to ultra-fine processing in the semiconductor device manufacturing field in recent years do not necessarily have sufficiently satisfactory characteristics. On the other hand, instead of naphthoquinone-1,2-diazidosulfonic 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 has not always been practically sufficiently improved in terms of the heat resistance of the resist pattern obtained therefrom, and when prepared as a coating solution, the photosensitive component Tends to precipitate and storage stability is poor.

[0005]

SUMMARY OF THE INVENTION Under these circumstances, the present invention has a sufficiently satisfactory sensitivity as a photoresist for use in ultrafine processing in the manufacture of semiconductor devices, The object of the present invention is to provide a highly practical positive photosensitive resin composition having excellent contrast, cross-sectional shape, particularly good heat resistance, and excellent storage stability.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to develop a positive photosensitive resin composition having the above-mentioned excellent characteristics. It has been found that the object can be achieved by adding a photosensitive component consisting of the following, and the present invention has been completed based on this finding.

That is, the present invention relates to a method in which an alkali-soluble novolak resin has a general formula

Embedded image (Wherein ^one of R ¹ and R ² is a methyl group and the other is a hydrogen atom, at least one of D ¹ , D ² and D ³ is a naphthoquinone-1,2-diazidosulfonyl group and the rest is hydrogen) A positive photosensitive resin composition comprising at least one compound selected from compounds represented by the following formula:

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the composition of the present invention, it is necessary to use at least one compound represented by the above general formula (I) as a photosensitive component. It dissolves well in solvents commonly used when used as a solution, and has good compatibility with the alkali-soluble novolak-type resin of the film-forming substance, and when used as a photosensitive component of a positive photoresist composition, it has high sensitivity. A composition having excellent image contrast, cross-sectional shape, storage stability, and excellent heat resistance is provided. These compounds have, for example, the general formula

Embedded image (Wherein R ¹ and R ² have the same meanings as described above), and naphthoquinone-1,2-
It can be produced by subjecting a diazidosulfonyl halide to a condensation reaction and subjecting it to complete or partial esterification. 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.

The trihydroxy compound represented by the general formula (II) includes bis (4-hydroxy-3,5
-Dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane and the like. These trihydroxy compounds are effective as raw material compounds for improving the heat resistance of the composition of the present invention.

On the other hand, naphthoquinone-1,2-diazidosulfonyl halide to be reacted with the above trihydroxy compound 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 trihydroxy compound 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, for example, sulfonyl chlorides such as orthobenzoquinonediazide, orthonaphthoquinonediazide, orthoanthraquinonediazide or orthonaphthoquinonediazide, and hydroxyl group or amino group, as long as the object of the present invention is not impaired. Compounds having groups such as phenol, p-methoxyphenol, dimethylphenol, hydroquinone,
Bisphenol A, naphthol, pyrocatechol, pyrogallol, polyhydroxybenzophenone, pyrogallol monomethyl ether, pyrogallol-1,3-dimethylether, gallic acid, gallic acid esterified or etherified leaving some hydroxyl groups, aniline, p-amino Reaction products with diphenylamine and the like can be used in combination.

Next, in the composition of the present invention, an alkali-soluble novolak resin is used as a substance for forming a film. 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 resin,
The weight average molecular weight obtained by cutting the low molecular weight region is 2,000
The use of 20,000, preferably 5000 to 15000, is advantageous for obtaining a composition having excellent heat resistance.

The mixing ratio of the alkali-soluble novolak type resin and the photosensitive component is 1: 2 to 2 by weight.
0: 1, preferably in the range of 1: 1 to 6: 1. If the amount of the photosensitive component used is smaller than this, an image faithful to the pattern cannot be obtained, and the transferability also decreases,
Further, when the amount of the photosensitive component used is larger than this, the uniformity of the formed resist film is reduced, and the resolution is also deteriorated.

The composition of the present invention is preferably used in the form of a solution obtained by dissolving the above-mentioned alkali-soluble novolak resin and a photosensitive component in a suitable solvent. Examples of such solvents include ketones such as acetone, methyl ethyl ketone, cyclohexanone, and methyl isoamyl ketone; ethylene glycol, ethylene glycol monoacetate, diethylene glycol or diethylene glycol monoacetate, or monomethyl ether, monoethyl ether, monopropyl ether thereof. , Polyhydric alcohols such as 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. These may be used alone or as a mixture of two or more.

In the composition of the present invention, if necessary, known sensitizers can be used in combination as long as the desired physical properties are not impaired. Such sensitizers include, for example, 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. One of these sensitizers may be used alone, or two or more of them may be used in combination, and the compounding amount is advantageously selected at 20% by weight or less based on the alkali-soluble novolak 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 for practical use. The composition of the present invention may further comprise, if necessary, compatible additives, for example, an additional resin, a plasticizer, a stabilizer for improving the performance of the resist film, etc., or make the developed image more visible. And commonly used materials such as coloring agents can be added.

Regarding the preferred method of using the composition of the present invention,
For example, first, on a support such as a silicon wafer, a solution in which an alkali-soluble novolak resin and a photosensitive component are dissolved in a suitable solvent as described above is applied by a spinner or the like, and dried to form a photosensitive layer. Then, using 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, or the like, exposure is performed through a required mask pattern, or irradiation is performed while scanning an electron beam. I do. Next, when this is immersed in a developing solution, for example, a weakly alkaline aqueous solution such as a 1 to 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.

[0018]

Next, the present invention will be described in more detail by way of 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 and dried on a hot plate at 110 ° C. for 90 seconds to obtain a 1.3 μm-thick resist film. A reduction projection exposure apparatus NSR-1505G4D (manufactured by Nikon Corporation) is applied to this film.
After exposure at 0.1 to 0.02 second intervals using, developing with a 2.38 wt% aqueous solution of tetramethylammonium hydroxide for 1 minute, washing with water for 30 seconds and drying, required for patterning The minimum exposure time was measured in milliseconds (ms) as the 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 was observed with a microscope. (4) Heat resistance: The resist pattern formed on the silicon wafer is formed at 110 ° C., 120 ° C., 130 ° C., 140
It was baked on a hot plate for 5 minutes at each temperature of 150 ° C. and 150 ° C., and the presence or absence of deformation of the pattern was evaluated as heat resistance according to the following criteria. …: No deformation △: slight deformation on the side, but no deformation at the contact with the silicon wafer ×: deformation at the contact with the 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 m-Cresol and p-cresol in a weight ratio of 40: 6
0, mixed with formalin, and subjected to a fractionation treatment on a cresol novolak resin obtained by condensation using an oxalic acid catalyst in a conventional manner, cutting a low molecular weight region to obtain a weight average molecular weight of 11, 000 cresol novolak resin was obtained. Next, 100 parts by weight of the cresol novolak resin thus obtained, bis (4-hydroxy-
1 mol of 2,5-dimethylphenyl) -2-hydroxyphenylmethane and naphthoquinone-1,2-diazide-5-
Esterification reaction product 3 with 3 mol of sulfonyl chloride
0 parts by weight and 1,3-bis (4-hydroxyphenyl)
After dissolving 15 parts by weight of propane in 350 g of ethyl lactate, this was filtered using a membrane filter having a pore size of 0.2 μm to prepare a photosensitive resin composition. Table 2 shows the physical properties of this product.

Comparative Examples 1 to 5 The same cresol novolak resin 1 as used in Example 1
The photosensitive components and the sensitizers shown in Table 1 were blended in respective amounts (parts by weight) with respect to 00 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 are parts by weight per 100 parts by weight of the novolak resin. Trisphenol TC: α, α ', manufactured by Mitsui Petrochemical Co., Ltd.
α "-tris (4-hydroxyphenyl) -1,3,5
Trade name of N-triisopropylbenzene NQS [5]; naphthoquinone-1,2-diazide-5-
Sulfonyl chloride

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

The positive photosensitive resin composition of the present invention contains a specific trihydroxy compound, naphthoquinone-1,2-diazidosulfonic acid ester, as a photosensitive component, and has a high sensitivity. Because the residual film ratio of the exposed part is high,
It has excellent features such as excellent cross-sectional shape and storage stability of the image contrast pattern, and can form a resist pattern with extremely high heat resistance compared to conventional ones, and also has high storage stability. It is suitably used as a resist for ultrafine processing in the manufacture of semiconductor devices such as LSIs and LSIs.

──────────────────────────────────────────────────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/ 00-7/14

Claims (1)

(57) [Claims] 1. An alkali-soluble novolak resin having a general formula: (Wherein ^one of R ¹ and R ² is a methyl group and the other is a hydrogen atom, at least one of D ¹ , D ² and D ³ is a naphthoquinone-1,2-diazidosulfonyl group and the rest is hydrogen) A positive photosensitive resin composition comprising at least one compound selected from the group consisting of: