JPH08179502A - Photosensitive resin composition - Google Patents

Abstract

PURPOSE: To obtain a photosensitive resin compsn. which has a high sensitivity and high resolution and deals with a KrF excimer laser by incorporating a resin contg. a specific phenol-dicyclopentadiene resin as an alkali-soluble resin component and a photoreaction component into this compsn. CONSTITUTION: This photosensitive resin compsn. contains 10 to 100wt.% phenol- dicyclopentadiene resin component expressed by the formula as the alkali-soluble resin and the photoreaction component into this compsn. In the formula, R<1> , R<2> respectively independently denote hydrogen atoms, 1 to 4C lower alkyl groups, phenyl groups, halogen atoms and hydroxyl groups which may be the same or different from each other; n denotes an integer from 0 to 20. More preferably, this photoreactive component normally suppresses the solubility of the alkali-soluble component and becomes a soluble component by losing the suppressing effect by photoirradiation. The alkali-soluble resin component contains further resins consisting of condensation products of phenols and aldehydes, polyhydroxystyrenes and styrene-maleic anhydride copolymers, etc.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel photosensitive resin composition and a pattern forming method using the same. More specifically, it has excellent sensitivity and high resolution,
The present invention relates to a photosensitive resin composition capable of fine processing and a pattern forming method using the same.

[0002]

2. Description of the Related Art Photosensitive resin compositions are used in various industrial fields, and are particularly important in the production of semiconductor devices such as ICs, LSIs and VLSIs. That is, a photosensitive resin composition is applied onto a substrate such as a silicon wafer, and the coating film of the photosensitive resin composition is irradiated with light through a mask pattern in which a pattern of a semiconductor device is drawn. A resist pattern can be drawn by utilizing the change in the solubility of the composition. There are various types of photosensitive resin compositions for such purposes. For example, as a positive resist, a novolak resin is often used as an alkali-soluble base resin, has an effect of suppressing the solubility of this base resin, and itself becomes an alkali-soluble type when irradiated with light. A photosensitive resin composition in which a compound containing a quinonediazide group is combined as a photoreactive component is often used. However, with the development of such industrial fields in recent years, the densification of semiconductor devices has rapidly increased, and inevitably, fine processing of resist patterns by lithography, that is, high sensitivity to a photosensitive resin composition,
Higher resolution is required.

In order to meet this demand, it is necessary to shorten the wavelength of the light source for exposure, and the g-line (43
6 nm), i-line (365 nm) to deep ultraviolet region, so-called excimer laser beam (ArF excimer; 193
nm, KrF excimer; 248 nm, XeCl; 308
nm). In particular, since the KrF excimer laser has a short wavelength, a large output, and stable oscillation, an exposure system using the same is drawing attention. However, the novolac type resin that has been widely used as an alkali-soluble base resin is
It has high absorption in the deep ultraviolet region and low transparency to these wavelengths. Therefore, the conventional novolac resist is not suitable for the exposure system corresponding to the excimer laser in terms of sensitivity and resolution.

[0004]

The object of the present invention is to find a highly transparent, alkali-soluble resin for excimer lasers, and by using it as a base resin, it is possible to expect high sensitivity and high resolution for excimer lasers, In particular, it is to provide a photosensitive resin composition that is compatible with a 248 nm KrF excimer laser.

[0005]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that certain phenolic resins have high transparency to excimer lasers, especially KrF excimer lasers. The resin is a known conventional method, that is, by combining with a photoreactive component, alkali solubility is suppressed in the normal state, and the photoreactive component in the exposed area is photo-modified to deactivate the suppression effect after exposure. However, the present invention has been found to be useful as a so-called positive photoresist in which photolithography becomes possible because it becomes alkali-soluble, and the present invention has been completed. That is, the present invention includes (A) a resin containing 10 to 100% by weight of a phenol-dicyclopentadiene resin represented by the general formula (1) (Chemical Formula 3) as an alkali-soluble resin component, and (B) light. The present invention relates to a photosensitive resin composition containing a reactive component.

[0006]

Embedded image (In the formula, R ¹ and R ² are each independently a hydrogen atom and a carbon number of 1
To 4 represent a lower alkyl group, a phenyl group, a halogen atom or a hydroxyl group, which may be different or the same, and n represents an integer of 0 to 20).

In the present invention, the phenol resin used as the base resin for photoresist is a phenol-dicyclopentadiene resin represented by the general formula (1) (hereinafter abbreviated as DPR resin). This resin has very low absorption near 248 nm, so
The transparency of the excimer laser is extremely high, and the hydroxyl group contributes greatly to the solubility of the alkali, which is in accordance with the gist of the present invention. This DPR resin is disclosed in JP-A-63-99224 and JP-A-04-1704.
23, JP-A-05-005022 and the like. That is, it is obtained by reacting an excess amount of a phenol compound with dicyclopentadiene in the presence of an acidic catalyst, and then distilling off an unreacted phenol compound.

Phenol compounds used in the reaction include phenol, o-cresol, m-cresol and p.
Monohydric phenols such as cresol, 2,4-xylenol, 2,6-xylenol, t-butylphenol, o-phenylphenol, p-phenylphenol,
Dihydric phenols such as resorcin, hydroquinone and catechol, 2-bromophenol, 4-bromophenol, 2-iodophenol, 4-iodophenol,
2-chlorophenol, 4-chlorophenol, 2,4
-Dibromophenol, 2,6-dibromophenol,
Examples thereof include halogenated phenols such as 2,4-diiodophenol and 2,6-diiodophenol. Among them, preferable phenol compounds include phenol, o-cresol, m-cresol and p-cresol, and these may be used alone or in combination of two or more kinds. The reaction molar ratio between the phenol compound and dicyclopentadiene is basically sufficient if the phenol compound is in a small excess amount or more, but the phenol / dicyclopentadiene (molar ratio) is 20 to 1.3, preferably 10 to 10.
The range is 1.5, more preferably 8 to 2. If the amount of phenol is small, the molecular weight will increase excessively during the reaction to cause gelation, and if it is too large, the amount of unreacted phenol compound will increase, and there will be a disadvantage in terms of volumetric efficiency of the reaction.

Although the catalyst used in the reaction is an acidic catalyst, such as an ethanol complex of boron trifluoride, a Lewis acid typified by aluminum chloride, an alkanesulfonic acid typified by methanesulfonic acid, or p-toluenesulfonic acid. Examples include organic sulfonic acids, super strong acids such as perfluoroalkane sulfonic acids typified by trifluoromethane sulfonic acid, ion exchange resins, etc., but problems such as the material of the reaction vessel and the pollution-free waste water, It is desirable to use methanesulfonic acid or trifluoromethanesulfonic acid when considering the cost. The usage is
In the case of methanesulfonic acid, 0.01 to 10 with respect to the raw material
% By weight, preferably in the range from 0.05 to 5% by weight, in the case of trifluoromethanesulphonic acid 0.000
It is in the range of 1 to 5% by weight, preferably 0.0005 to 1% by weight.

The reaction is classified into a first step in which dicyclopentadiene undergoes an addition reaction with a hydroxyl group of phenol to be etherified, and a second step in which the ether form a phenol resin by a rearrangement reaction. The reaction temperature is 20 to 20
The temperature is 0 ° C, preferably 40 to 160 ° C. After the completion of the reaction, the unreacted phenol compound can be distilled off by an arbitrary method to obtain a DPR resin, but it is desirable to introduce a washing step when the DPR resin is used for the purpose of the present invention. The washing method may be any method, for example, a method of using an alkali metal hydroxide to remove components that are insoluble in water as an alkali metal salt, aromatic hydrocarbons such as toluene and xylene, and methyl ethyl ketone. , Ketones such as methyl isobutyl ketone, amyl alcohol, isoamyl alcohol, heptanol,
Method of washing with water using an organic solvent such as higher alcohols such as 2-heptanol, octanol and isooctanol, method of washing with dilute hydrochloric acid using the above organic solvent, 1,2-dichloroethane, chloroform, methyl cellosolve, ethyl cellosolve, dimethyl There is a method of treating with an adsorbent such as silica gel, alumina and activated carbon using a solvent such as formamide and dimethylacetamide. It is desirable to reduce impurities such as gel components, acidic components, metal ions, etc. as much as possible by any one of these methods or a combination of these methods.

The DPR resin thus obtained is used alone or in combination with other alkali-soluble resins as the alkali-soluble component of the photosensitive resin composition. Other alkali-soluble components that can be used in combination include novolac, a novolac resin obtained by condensing aldehydes with phenols such as cresol novolac, polyhydroxystyrene and its hydride, styrene-maleic anhydride copolymer, polymethyl. Methacrylate etc. are mentioned. The use ratio is within the range in which the characteristics of the DPR resin are expressed, and specifically, the DPR resin is in the range of 10 to 100% by weight in the total alkali-soluble component, preferably,
The range is 25 to 100% by weight, and more preferably 50 to 100% by weight.

As the photoreactive component used together with the alkali-soluble component in the present invention, all known photoreactive compounds can be used, but in the normal state, the ability to suppress the alkali-solubility of the alkali-soluble resin is used. It is preferable to use a photoreactive compound that has a longevity and deactivates its ability upon irradiation with light. In the present invention, the normal state means that the photosensitive resin composition of the present invention containing an alkali-soluble resin and a photoreactive component is not exposed to a light source for exposure having a wavelength shorter than visible light, and further, It means a state in which the semiconductor device substrate is not exposed to the light source for exposure when it is applied on the substrate. The photoreactive component used in the present invention is, for example, 1,2
A naphthoquinone-2-diazide or a sulfonic acid ester thereof, or a compound represented by the general formula (2) (formula 4).

[0013]

[Chemical 4] (In the formula, R ³ represents an alkyl group or an alkoxy group having 1 to 6 carbon atoms, R ⁴ represents hydrogen or an alkyl group having 1 to 6 carbon atoms, and when R ³ and R ⁴ are both alkyl groups, R ⁵ may form a ring with each other, and R ⁵ is a polyfunctional aliphatic group that binds constituent components other than R ⁵ , and m represents an integer of 3 or more.)

More specifically, 1,2-naphthoquinone-
2-diazide, and its esters include 1,2-
Naphthoquinone-2-diazide-4 (5) -sulfonic acid chloride and phenol, p-methoxyphenol, dimethylphenol, hydroquinone, p-phenylphenol, α-naphthol, β-naphthol, 2,6-dihydroxynaphthalene, biphenol, Bisphenol A, polyhydroxybenzophenone, 1,3-dihydroxy-4,6-bis ((4-hydroxyphenyl-dimethyl) methyl) -benzene, 6,6'-dihydroxy-
3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane, a phenol aralkyl resin represented by the general formula (3) (formula 5), and a general formula (4) (formula 5) By reacting with a naphthol-aralkyl resin, a phenol-dicyclopentadiene resin represented by the general formula (5) (formula 5), a phenol resin represented by the general formula (6) (formula 5), polyhydroxystyrene, etc. It is preferable that the obtained esterified product has an esterification rate in the range of 5 to 100%.

[0015]

Embedded image (In the above formula, R ⁶ and R ⁷ each independently represent a hydrogen atom, a methyl group, a hydroxyl group, or a phenyl group, and they may be different or the same, and R ⁸ and R ⁹ are each independently Hydrogen atom, lower alkyl group having 1 to 4 carbon atoms, phenyl group,
A halogen atom and a hydroxyl group, which may be different or the same as each other, R ¹⁰ represents a hydrogen atom or a methyl group, and n represents an integer of 0 to 20)

The phenol aralkyl resin represented by the general formula (3) can be obtained as follows. That is, JP-B-47-15111 and JP-A-63-2381.
29, JP-A-6-100667, etc., and a phenol component corresponding to a phenol residue,
A compound obtained by reacting an aralkyl halide or an aralkyl alcohol derivative represented by the general formula (7) (Chemical Formula 6) with an excess of a phenol component in the presence of an acid catalyst to remove an unreacted phenol component. is there.
Similarly, the naphthol aralkyl resin represented by the general formula (4) is reacted with an excess amount of naphthol and an aralkyl halide or an aralkyl alcohol derivative in the presence of an acid catalyst, as shown in JP-A-6-184274. It is obtained by removing unreacted naphthol component.

[0017]

[Chemical 6] (In the formula, R is a halogen atom, a hydroxyl group, or a carbon number of 4
Represents the following lower alkyl group)

The phenolic resin represented by the general formula (6) is a resin generally well known as a novolak resin, which is obtained by reacting phenols and formaldehyde in the presence of an acid catalyst. Hydroxystyrene is also obtained by radically polymerizing hydroxystyrene. Further, as the compound represented by the general formula (2), specifically, the compound (8), the compound (9), the compound (10), the compound (11), the compound (1
2) and compounds represented by the compound (13) (Chemical formula 7). These compounds are disclosed in JP-A-3-711.
It is produced by the method described in No. 39.

[0019]

[Chemical 7]

In the normal state, these compounds suppress the alkali solubility by hydrogen bonding with the hydroxyl group of the alkali-soluble resin, and are photolyzed by irradiation with light to be modified into ketene and further resist. It is presumed that by reacting with moisture in the film or in the air to rapidly generate a carboxyl group, the polarity of the exposed portion is largely changed, and the solubility in the alkaline aqueous solution is rapidly and significantly increased. That is, by utilizing these properties, the present invention makes it possible to obtain a so-called positive resist pattern. In the present invention, the amount of the photoreactive component mixed with the alkali-soluble resin is 1 part by weight with respect to 100 parts by weight of the alkali-soluble resin.
To 100 parts by weight, preferably 5 to 90 parts by weight, more preferably 10 to 70 parts by weight.

The photosensitive resin composition of the present invention is dissolved in an organic solvent and is 1 to 50% by weight, preferably 5 to 35% by weight.
A uniform photosensitive resin layer can be formed by applying and drying a solution having a concentration range of 1 on the surface of the substrate. For example, an organic solvent solution of the photosensitive resin composition of the present invention is uniformly applied to an arbitrary substrate such as a silicon wafer by a spinner or the like, and this is applied at 50 to 130 ° C.
Preferably, the photosensitive resin composition layer may be formed by drying at 80 to 110 ° C. In order to draw a resist pattern on this coating film, it is irradiated with light through a positive type photomask pattern, and then 1 to 10 parts by weight of an alkali developing solution, for example, quaternary ammonium hydroxide such as tetramethylammonium hydroxide. % Aqueous solution, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution or the like 1-10% by weight aqueous solution of alkali metal hydroxide, or 1-10% by weight choline aqueous solution or other alkaline aqueous solution for development processing By doing so, an arbitrary resist pattern can be obtained.

As the organic solvent, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl isoamyl ketone and cyclohexanone, ethylene glycol, diethylene glycol, ethylene glycol monoacetate, diethylene glycol monoacetate,
Polypropylene glycol, dipropylene glycol, propylene glycol monoacetate, dipropylene glycol monoacetate, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monopropyl ether, dipropylene glycol monobutyl ether, etc. Dihydric alcohols and their derivatives, tetrahydrofuran, cyclic ethers such as dioxane, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, etc. Examples thereof include, but are not limited to, esters and the like and mixtures thereof. still,
In the present invention, a resist pattern is obtained by irradiating the coated surface with light. The exposure wavelength is from g-line (436 nm), i-line (365 nm) to deep ultraviolet region, particularly, so-called Excimer laser (Ar
F excimer; 193 nm, KrF excimer; 248n
m, XeCl; 308 nm).

The photosensitive resin composition of the present invention is particularly suitable for DP
Around 248 nm where the absorption of R resin is minimum, that is,
It is applicable to the KrF excimer laser, which has received a great deal of attention in recent years, and is expected to greatly contribute to the industrial field. Further, the photosensitive resin composition of the present invention is a photosensitive component that generates an acid upon irradiation with light, and in the normal state, suppresses the solubility of the alkali-soluble component, and by an acid generated by irradiation with light. A combination with a component that loses its suppression effect and becomes an alkali-soluble component, a so-called chemically amplified resist, or a combination with a component that becomes a cross-linking agent by light irradiation, so-called, can be used as a negative photoresist. is there.

[0024]

The present invention will be described in more detail with reference to Examples. However, the present invention is not limited to these examples. Synthesis Example 1 A glass reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser was charged with 470 g (5 mol) of phenol; and 0.03 g of trifluoromethanesulfonic acid; Dicyclopentadiene 1 at ℃
32 g (1 mol) was added dropwise over 1 hour while maintaining the same temperature. After continuing stirring at the same temperature for 1 hour, the temperature was raised and stirring was continued at 150 ° C. for 2 hours to complete the reaction. After unreacted phenol was distilled off under reduced pressure, it was dissolved in 800 g of 1,2-dichloroethane,
280 g of DPR resin was obtained by sludge using 200 g of silica gel at room temperature, adsorbing and purifying the catalyst and others, and removing dichloroethane. The composition (GPC area%) of this resin was as follows. n = 0: 47.2%, n = 1: 27.0%, n = 2: 1
4.6%, n ≧ 3: 10.9% The UV absorption spectrum of the obtained resin is shown in (FIG. 1). Based on (FIG. 1), the gram extinction coefficient εg at 248 nm was determined by the following equation, and was εg = 1.20. Gram extinction coefficient ε g = A / d · l A (Absorbance) = 0.13, l (cell length) = 1
cmd (concentration) = 0.1086 mg / ml (solvent: acetonitrile)

Synthesis Example 2 1,2-naphthoquinone-2-diazide-4-sulfonic acid chloride; 118.1 g (0.44 mol) was placed in a glass reaction vessel equipped with a stirrer, a thermometer and a reflux condenser.
24.6 g of tetrahydroxybenzophenone (0.1 m
Ol) is dissolved in 300 g of dimethylacetamide, and 30% of triethylamine; 42.4 g is added with stirring.
The mixture was added dropwise over a period of 2 minutes, and the mixture was further stirred for 2 hours, and then the precipitate was filtered off. Then, 250 g of a 1% hydrochloric acid aqueous solution was added dropwise to the obtained filtrate to precipitate a reaction product. This product was filtered off, thoroughly washed with ion-exchanged water, and dried. G
The purity by PC was 100%.

Example 1 As the alkali-soluble resin, the DPR resin produced in Synthesis Example 1; 12 g, as the photoreactive component, Synthesis Example 2
3.3 g of the tetranaphthoquinone diazide sulfonic acid ester produced in (3) was dissolved in ethyl cellosolve acetate, and a 35 wt% ethyl cellosolve acetate solution was prepared to obtain a positive resist solution. This resist solution was spin-coated on a silicon wafer at 2000 rpm and prebaked in an oven at 80 ° C. for 20 minutes to obtain a coating film having a film thickness of 1 μm. This coating is 5: 1
KrF excimer laser exposure was performed by a reduction projection exposure method using a photomask chart having a positive pattern. After exposure, it was developed with a 1% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute to obtain a positive resist pattern. The cross-sectional shape of this resist pattern,
It was observed with a microscope and it was confirmed that the side face was vertical and a good pattern was obtained.

Comparative Example 1 The alkali-soluble resin used in Example 1 was replaced with novolac resin [Mirex # 2000, manufactured by Mitsui Toatsu Chemicals, Inc.] 1.
The film thickness was 1 μm in the same manner as in Example 1 except that the film thickness was changed to 2 g.
m coating film was obtained. Further, the same exposure and development as in Example 1 were performed. When the cross section of the obtained resist pattern was observed with a microscope, a good pattern was not obtained because the novolak resin had strong absorption around 248 nm. The UV absorption spectrum of the novolac resin used is shown in (FIG. 2). Based on (Fig. 2), the Gram extinction coefficient εg at 248 nm is calculated by the above equation.
g = 4.63. A (Absorbance) = 0.25, l (cell length) = 1
cmd (concentration) = 0.054 mg / ml (solvent: acetonitrile)

Examples 2 to 22 In the same manner as in Synthesis Example 1, the phenol in Synthesis Example 1 was replaced with various substituted phenols shown below to obtain corresponding substituted phenol-dicyclopentadiene resins.
Using these various substituted phenol-dicyclopentadiene resins, in the same manner as in Example 1, various positive resist solutions were obtained. These various resist solutions were spin-coated on a silicon wafer at 2000 rpm, prebaked in an oven at 80 ° C. for 20 minutes,
Various coating films having a film thickness of 1 μm were obtained. Each of these coating films was subjected to KrF excimer laser exposure by a 5: 1 reduction projection exposure method using a photomask chart having a positive pattern. After exposure, it was developed with a 1% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute to obtain a positive resist pattern. The cross-sectional shape of each of these resist patterns was observed using a microscope, and it was confirmed that the side face was vertical and a good pattern was obtained. The phenol compounds used in each example are as follows. o-cresol, m-cresol, p-cresol, 2,4-xylenol, 2,6-xylenol, t
-Butylphenol, o-phenylphenol, p-phenylphenol, resorcin, hydroquinone, catechol, 2-bromophenol, 4-bromophenol, 2-iodophenol, 4-iodophenol, 2
-Chlorophenol, 4-chlorophenol, 2,4-
Dibromophenol, 2,6-dibromophenol,
2,4-diiodophenol and 2,6-diiodophenol.

Examples 23 to 40 In Example 1, instead of tetranaphthoquinonediazide sulfonic acid ester as the photoreactive component, 1,2-
Naphthoquinone-2-diazide, and, in Synthesis Example 2, instead of tetrahydroxybenzophenone, using various sulfonic acid esters of 1,2-naphthoquinone-2-diazide obtained by using the following various phenols, respectively, A positive resist pattern was obtained in the same manner as in Example 1. The cross-sectional shape of each resist pattern was observed using a microscope, and it was confirmed that the side face was vertical and a good resist pattern was obtained. The phenol compounds used for esterification in each example are as follows. Phenol, p-methoxyphenol, dimethylphenol, hydroquinone, p-phenylphenol, α-naphthol, β-naphthol, 2,6-dihydroxynaphthalene, biphenol, bisphenol A,
1,3-dihydroxy-4,6-bis ((4-hydroxyphenyl-dimethyl) methyl) -benzene, 6,6 ′
-Dihydroxy-3,3,3 ', 3'-tetramethyl-
1,1'-spirobiindane, phenol aralkyl resin [Mitsui Toatsu Chemicals, Inc., Milex XL-225-
L], p-xylylene dichloride 1 mol, β
-4 mol of naphthol was reacted and β-naphthol-aralkyl resin obtained by distilling off unreacted β-naphthol, phenol-dicyclopentadiene resin obtained in Synthesis Example 1, novolak resin [Mitsui Toatsu Chemical ( Co., Ltd., Millex # 2000], polyhydroxystyrene having a weight average molecular weight of 5000.

Examples 41 to 46 In Example 1, the above formula (8) was used as the photoreactive component.
When various compounds represented by (13) to (13) were used and treated in the same manner, good resist patterns were obtained in all cases.

Examples 47-54 Ten of the alkali-soluble resins in Example 1
It was confirmed that a good resist pattern could be obtained in any case by replacing the resin by weight% with the resin shown below and performing the same treatment. The resin used in each example is as follows. Novolac resin [Mitsui Toatsu Chemicals, Inc.
Millex # 2000], o-cresol novolac resin (weight average molecular weight 2000), m-cresol novolac resin (weight average molecular weight 2200), p-cresol novolac resin (weight average molecular weight 2000), polyhydroxystyrene having weight average molecular weight 5000, Hydrogenated polyhydroxystyrene [Maruzen Petrochemical, PHM-
C], styrene-maleic anhydride copolymer (weight average molecular weight 5500, styrene content 65 mol%), polymethylmethacrylate (weight average molecular weight 5000, esterification rate 60 mol%).

As described above, the present invention relates to a photosensitive resin composition for obtaining a positive resist pattern, which is characterized by using a DPR resin as an alkali-soluble resin as a constituent component thereof. Is.
This DPR resin has g-line (436 nm) and i-line (365) which are the exposure wavelengths conventionally used in the industrial field as shown in the UV absorption spectrum of (FIG. 1).
nm), and the excimer laser that has received a great deal of attention in recent years, because it corresponds to the processing precision of the ultrafine pattern required for the production of semiconductor devices with higher integration for the next generation, Since the absorption around the existing KrF excimer laser (248 nm) is very small, it is possible to sufficiently cope with the pattern forming system using the KrF excimer laser. It can be seen from the fact that a good pattern is observed in Example 1, which makes a great contribution to the industrial field.

On the other hand, the novolak resin, which is a typical skeleton as a conventional alkali-soluble resin, has a large absorption around 248 nm as can be seen from the UV absorption spectrum of FIG. It is difficult to support a pattern forming system compatible with a KrF excimer laser, and in Comparative Example 1, a good pattern was not actually formed. It is speculated that this is due to the absorption of KrF excimer laser in the novolac resin.
Further, by comparing the gram extinction coefficient obtained based on (FIG. 1) and (FIG. 2), it is found that the transparency at 248 nm of the DPR resin used in the present application is about four times that of the novolac resin.

[0034]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, in addition to the g-line and i-line wavelengths conventionally used for DPR resins,
It was made by discovering that the absorption around 48 nm is very small, and it is indispensable for manufacturing high density semiconductor devices such as LSI and VLSI, which is not difficult to predict that demand will expand rapidly in the future. It greatly contributes to the development of a KrF excimer laser-compatible system capable of forming a fine resist pattern with excellent accuracy in terms of sensitivity and resolution.

[Brief description of drawings]

FIG. 1 is a UV absorption spectrum of a DPR resin obtained in Synthesis Example 1.

FIG. 2 is a UV absorption spectrum of the novolac resin used in Comparative Example 1.

Claims (6)

[Claims] 1. The (A) alkali-soluble resin component,
A photosensitive resin composition comprising: a resin containing 10 to 100% by weight of a phenol-dicyclopentadiene resin represented by the general formula (1) (Chemical formula 1); and (B) a photoreactive component. Embedded image (In the formula, R ¹ and R ² are each independently a hydrogen atom and a carbon number of 1
To 4 represent a lower alkyl group, a phenyl group, a halogen atom or a hydroxyl group, which may be different or the same, and n represents an integer of 0 to 20). 2. The photosensitive resin according to claim 1, wherein the photoreactive component suppresses the solubility of the alkali-soluble component in the normal state and loses its suppressing effect by light irradiation to become a soluble component. Composition. 3. The alkali-soluble resin component is at least one selected from the group consisting of condensation products of phenols and aldehydes, polyhydroxystyrenes, and styrene-maleic anhydride copolymers. The photosensitive resin composition according to claim 1 or 2, containing the resin according to claim 1. 4. The photoreactive component is at least one selected from the group consisting of 1,2-naphthoquinone-2-diazides and sulfonic acid esters thereof. The photosensitive resin composition described. 5. The photoreactive component is represented by the general formula (2)
The photosensitive resin composition according to claim 1, which is a compound represented by: Embedded image (In the formula, R ³ represents an alkyl group or an alkoxy group having 1 to 6 carbon atoms, R ⁴ represents hydrogen or an alkyl group having 1 to 6 carbon atoms, and when both R ³ and R ⁴ are alkyl groups, R ⁵ may form a ring, and R ⁵ is a polyfunctional aliphatic group that bonds constituent components other than R ⁵ , and m represents an integer of 3 or more.) 6. The coating film of the photosensitive resin composition according to claim 1 is used for forming a pattern of a semiconductor device by irradiating the coating film of the photosensitive resin composition with light. A pattern forming method characterized by the above.