JP3319826B2 - Positive photosensitive resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel positive photoresist composition, and more particularly, to a high-sensitivity image contrast suitable for use as a resist for ultrafine processing in the manufacture of semiconductor devices such as ICs and LSIs. The present invention relates to a positive photosensitive resin composition which is excellent in the cross-sectional shape of a pattern and can form a resist pattern having particularly excellent depth of focus characteristics and 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. In this method, an active ray such as ultraviolet rays is irradiated through a mask pattern, developed, and then 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:
Sensitivity, image contrast, cross-sectional shape,
The depth of focus characteristics and heat resistance do not always have sufficiently satisfactory characteristics. On the other hand, naphthoquinone-1,2-polyhydroxybenzophenones
By using a specific tris (hydroxyphenyl) methane compound naphthoquinone-1,2-diazidosulfonic acid ester as a photosensitive component instead of diazidosulfonic acid ester, it has positive characteristics suitable for ultrafine processing. Type photoresist compositions have also been proposed (Japanese Patent Laid-Open No.
189644). However, this positive photoresist composition has not always been practically sufficiently improved in terms of depth of focus characteristics and heat resistance of a resist pattern obtained therefrom, and was prepared as a coating solution. In this case, there is a problem that a photosensitive component is easily precipitated and storage stability is poor.

[0005]

SUMMARY OF 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 highly practical image having excellent image contrast and cross-sectional shape, particularly excellent depth of focus characteristics and heat resistance, and excellent storage stability.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to develop a positive photoresist composition having the above-mentioned excellent characteristics. As a result, the alkali-soluble novolak-type resin contains a special compound. It has been found that the purpose can be achieved by adding a photosensitive component, 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 Or general formula

Embedded image (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. 1 and m are integers of 1 to 3, n is 0
Or an integer of 1 to 3). A positive photosensitive resin composition comprising at least one compound selected from compounds represented by the formula:

Next, the configuration of the present invention will be described. In the composition of the present invention, at least one compound represented by the general formula (I) or (II) is used as a photosensitive component.
Although it is necessary to use seeds, these compounds dissolve well in a solvent commonly used when the composition is used as a solution, and have good compatibility with the alkali-soluble novolak-type resin of the film-forming substance. Yes, when used as a photosensitive component of a positive photoresist composition, it provides a composition that is highly sensitive, has excellent image contrast, cross-sectional shape, storage stability, and is also excellent in depth of focus characteristics and heat resistance.

[0009] As the compound represented by the general formula (I), for example the general formula

Embedded image Compounds represented by (D ^1, D ² and D ³ in the formula have the same meanings as defined above) or the general formula

Embedded image (D ¹ in the ^{formula, D 2, D 3, l} , m and n have the same meanings as defined above) can be mentioned compounds represented by, in particular the general formula

Embedded image (Wherein D ¹ , D ² and D ³ have the same meanings as described above).

On the other hand, as the compound represented by the general formula (II), for example, the compound represented by the general formula (VI)

Embedded image Compounds represented by (D ^1, D ² and D ³ in the formula have the same meanings as defined above) or the general formula

Embedded image (D ¹ in the ^{formula, D 2, D 3, l} , m and n have the same meanings as defined above) can be mentioned compounds represented by, in particular the general formula

Embedded image (Wherein D ¹ , D ² and D ³ have the same meanings as described above).

The compounds represented by the general formula (I) or (II), for example, each of the general formula

Embedded image Or general formula

Embedded image (L in the formula, m and n Tsu also as defined above) to the tris (hydroxyphenyl) methanes represented by, to a condensation reaction of naphthoquinone-1,2-diazide sulfonyl halide, fully esterified or partially It can be produced by 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.

[0012] Examples of the general formula starting compound represented by (IX), For example bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3-hydroxyphenyl methane, bis (5-cyclohexyl-4-hydroxy -2-methylphenyl) -4-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-
Methylphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2,3-dimethylphenyl) -3-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2,3-dimethylphenyl ) -4-Hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2,3-dimethylphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-3,6-dimethylphenyl)- 2-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-3,6-dimethylphenyl) -3-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-3,6-dimethylphenyl) -4- Hydroxyphenylmethane, bis (5-cyclo Sill-4-hydroxy -2,3,6
-Trimethylphenyl) -2-hydroxyphenylmethane , bis (3-cyclohexyl-4-hydroxy-2-
Etc. methylphenyl) -4-hydroxy-3,5-dimethylphenyl methane may be mentioned, in particular the sensitivity of the composition of the present invention, as the starting compound for improving the focal depth range properties and heat resistance, the general formula

Embedded image In those represented, for example, bis (5-cyclohexyl -
4-hydroxy-2-methylphenyl) -2-hydroxyphenyl methane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -4-hydroxyphenyl methane, etc. are preferable, bis Among these (5- Cyclohexyl-4-hydroxy-2-methylphenyl)
2-Hydroxyphenylmethane is most preferred.

Meanwhile, examples of the starting compound represented by the general formula (X), bis (5-cyclohexyl-2-hydroxy-4-methylphenyl) -2-hydroxyphenyl methane, bis (5-cyclohexyl-2 -Hydroxy-4-methylphenyl) -4-hydroxyphenylmethane, bis (5-cyclohexyl-2-hydroxy-
4,6-dimethylphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-2-hydroxy-
4,6-dimethylphenyl) -4-hydroxyphenylmethane, bis (5-cyclohexyl-2-hydroxy-
3,4-dimethylphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-2-hydroxy-
4-methylphenyl) -2-hydroxy-4-methylphenylmethane, bis (5-cyclohexyl-2-hydroxy-4-methylphenyl) -2-hydroxy-3,
4,5 trimethylphenyl methane, bis (5-cyclohexyl-2-hydroxy-3,4-dimethylphenyl) -4-hydroxy-2,3,5 etc. trimethylphenyl methane may be mentioned, in particular the present invention As a raw material compound for improving the sensitivity, depth of focus characteristics and heat resistance of the composition, a general formula

Embedded image In those represented, for example, bis (5-cyclohexyl -
2-hydroxy-4-methylphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-2-hydroxy-4-methylphenyl) -4-hydroxyphenylmethane and the like, especially , bis (5-cyclohexyl- 2-hydroxy-4-methylphenyl) -2-
Hydroxyphenylmethane is most preferred.

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

The photosensitive component of the present invention has the general formula (I)
All of the hydroxyl groups in the compound represented by X) or (X) may be esterified, or a part thereof may be esterified. Also, these photosensitive components are
They 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. Among these alkali-soluble novolak resins, a cresol novolak resin obtained from a mixed cresol of m-cresol and p-cresol is particularly suitable.

In the composition of the present invention, the alkali-soluble novolak type resin having a weight average molecular weight of 2000 to 20,000, preferably 5000 to 15000, obtained by cutting a low molecular weight region, is preferably used. It is advantageous to obtain

The compounding ratio of the alkali-soluble novolak type resin to the photosensitive component represented by formula (I) or (II) is 1: 2 to 20: 1 by weight, preferably 1: 1 to 6: It is selected within the range of 1. 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 composition of the present invention is preferably used in the form of a solution obtained by dissolving the alkali-soluble novolak resin and the photosensitive component in a suitable solvent.

Examples of such a solvent include acetone,
Ketones such as methyl ethyl ketone, cyclohexanone, and methyl isoamyl ketone; polyhydric alcohols such as ethylene glycol, ethylene glycol monoacetate, diethylene glycol or diethylene glycol monoacetate, such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether; Cyclic derivatives such as dioxane; and esters such as ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate. it can. 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 together 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, α, α ′, α ″ -tris (4-hydroxyphenyl) -1,3,5-triisopropylbenzene 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 preferably 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 20% by weight, no improvement in the sensitizing effect is recognized for the amount, which is not preferable in practical use.

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

About 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.

[0025]

The positive photosensitive resin composition of the present invention contains a specific tris (hydroxyphenyl) methane compound naphthoquinone-1,2-diazidesulfonic acid ester as a photosensitive component. High sensitivity, high residual film ratio of unexposed areas, excellent in cross-sectional shape and storage stability of image contrast pattern, and formation of resist pattern with extremely excellent depth of focus characteristics and heat resistance compared to conventional ones It has excellent characteristics such as high storage stability 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.

[0026]

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: A 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. Using a reduced projection exposure apparatus NSR-1505G4D (manufactured by Nikon Corporation) on this film,
After exposing at intervals of 0.1 second to 0.01 second, 2.38
When developed with a weight% aqueous solution of tetramethylammonium hydroxide at 23 ° C. for 1 minute, washed with water for 30 seconds and dried, the minimum exposure time required for patterning 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-described sensitivity measurement was measured, and the residual film ratio was determined from the ratio.

(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: The resist pattern formed on the silicon wafer
The pattern was baked on a hot plate at a temperature of 10 ° 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 at the contact with the silicon wafer,
×: Deformation observed at the contact portion with the silicon wafer

(5) Storage stability: The coating solution of the prepared 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.

(6) Depth of focus width: A line-and-space pattern of 0.5 μm is formed one-to-one using a reduction projection exposure apparatus NSR-1755i7B (manufactured by Nikon Corporation, NA = 0.54). The minimum exposure time required for the exposure) is taken as a reference exposure amount, and the focus is shifted up and down as appropriate at the exposure amount, and SEM (scanning electron microscope) of the resist pattern obtained by exposure and development is performed.
A photograph was observed. According to the SEM photograph, 0.5 μm
The maximum value (μm) of the defocus that can obtain the rectangular resist pattern is defined as the depth of focus, C is 0.4 to 0.7 μm, B is 0.8 to 1.1 μm, and A is 1.2 or more. Was evaluated.

Example 1 m-cresol and p-cresol were mixed 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, 1 mol of bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -2-hydroxyphenylmethane and naphthoquinone-1,2-diazide After dissolving 30 parts by weight of an esterification reaction product with 3 mol of -5-sulfonyl chloride in 350 parts by weight of ethyl lactate, this was filtered using a membrane filter having a pore size of 0.2 μm to obtain a positive photosensitive resin composition. Was prepared. Table 3 shows the characteristics.

Examples 2 to 6 With respect to 100 parts by weight of various novolak resins shown in Tables 1 and 2, various tris (hydroxyphenyl) methanes and naphthoquinone-1,2-diazide shown in Tables 1 and 2 were used. Various positive photosensitive resin compositions were prepared by blending the condensation products with the sulfonyl chloride at the ratios shown in Table 1. Table 3 shows the characteristics.

Comparative Examples 1 to 3 The same cresol novolak resin 1 as used in Example 1
A photosensitive component was prepared by mixing a photosensitive component as shown in Table 2 with respect to 00 parts by weight. Table 3 shows the characteristics.

[0037]

[Table 1]

[0038]

[Table 2]

(Note) The abbreviation symbols in the table mean the following compounds, and the amount of the photosensitive component used is indicated by parts by weight per 100 parts by weight of the novolak resin. NQS [4]; naphthoquinone-1,2-diazide-4-
Sulfonyl chloride NQS [5]; naphthoquinone-1,2-diazide-5-
Sulfonyl chloride

[0040]

[Table 3]

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nobuo Tokutake 150 Nakamaruko, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Tokyo Oka Kogyo Co., Ltd. (72) Inventor Hidekatsu Ohara 150 Nakamaruko, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Tokyo Oka Kogyo Incorporated (72) Inventor Toshimasa Nakayama 150 Nakamaruko, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Tokyo Ohka Kogyo Co., Ltd. (56) References JP-A-6-19130 (JP, A) JP-A-6-301203 (JP) , A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03F ^7/ 00-7/42

Claims (5)

(57) [Claims] 1. An alkali-soluble novolak resin having a general formula: Or (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. 1 and m are integers of 1 to 3 , n is 0
Or a positive photosensitive resin composition comprising at least one compound selected from the compounds represented by the following formulas: 2. A method according to claim 1, wherein the photosensitive component has 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 ; 1 and m are integers of 1 to 3, n is 0
Or 1 to 3 is an integer) at least one a is claim 1 positive photosensitive resin composition according selected from among compounds represented by. 3. The photosensitive component has a general formula: (D ^1, D ² and D ³ in the formula, at least one naphthoquinone-1,2-diazide sulfonyl groups therein, remainder Ri Oh a hydrogen atom, l and m is an integer of 1 to 3 , N is 0
Or 1 to 3 is an integer) at least one a is claim 1 positive photosensitive resin composition according selected from among compounds represented by. 4. The photosensitive component has a general formula: (D ^1, D ² and D ³ in the formula, at least one naphthoquinone-1,2-diazide sulfonyl groups therein, remainder Oh Ru hydrogen atom) selected from among compounds represented by The positive photosensitive resin composition according to claim 2, which is at least one kind. 5. The photosensitive component of the general formula: (D ^1, D ² and D ³ in the formula, at least one naphthoquinone-1,2-diazide sulfonyl groups therein, remainder Oh Ru hydrogen atom) selected from among compounds represented by The positive photosensitive resin composition according to claim 3, which is at least one kind.