JP3529177B2 - Photosensitive resin composition - Google Patents

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 relates to a photosensitive resin composition having excellent sensitivity and high resolution and 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 ICs, LSIs, VLSIs, etc.
It is particularly important in manufacturing semiconductor devices. 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 solubility. 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, when novolac resin is used as the base resin, heat resistance becomes a problem. Usually, the following steps are performed to form a pattern. That is, the photosensitive resin composition is applied onto the substrate, prebaked,
The seven steps are light irradiation through a photomask, development, post-baking, dry etching, and stripping. Among these steps, during the post bake of
A temperature of about 130-160 ° C is applied. At this time, when a novolac resin is used as the base resin, the heat resistance is inferior and the pattern is deformed, which is not suitable for obtaining a high-resolution pattern. With the development of such industrial fields in recent years, the density of semiconductor devices is rapidly increasing, and inevitably, fine processing of resist patterns by lithography, that is, higher sensitivity and higher resolution for photosensitive resin compositions are required. However, due to the intrinsic heat resistance of the novolac resin, the present situation does not meet the above demand.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to find a resin excellent in heat resistance, which is an alternative to novolac resin, and to use it as a base resin to obtain i-line (365 mm), g
It is to provide a photosensitive resin composition that can be applied to a line (436 mm) and can be expected to have high sensitivity and high resolution.

[0005]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that certain polythioethers have excellent heat resistance, and by combining this with a photosensitive component, high sensitivity can be obtained. The inventors have found that a high-resolution photosensitive resin composition can be obtained, and completed the present invention.
That is, the present invention requires a polythioether represented by the following general formula (1) (Chemical Formula 3) as an alkali-soluble component in a photosensitive resin composition containing an alkali-soluble component and a photosensitive component. The present invention relates to a photosensitive resin composition containing 1 to 100% as a component, and a method for producing a semiconductor device in which the composition is applied onto a substrate to form a coating film and patterned by light irradiation.

[0006]

[Chemical 3] (In the formula, A represents a phenol or / and a naphthol residue, and n represents an integer of 0 to 100)

The photosensitive resin composition of the present invention contains an alkali-soluble component, a photosensitive component and a solvent, and if necessary, additives such as a sensitizer and an antihalation agent may be added. It is possible. The polythioether represented by the general formula (1) used as the alkali-soluble component of the present invention is a compound in which a phenol or / and a naphthol is bound with a sulfur atom. These compounds are described in USP 3743680, Tetrahedron Vol 25 p.4593 ~ 4597.
(1969). That is, it is obtained by reacting an excess amount of phenols and / or naphthols with sulfur or sulfur chloride in the presence or absence of an alkali catalyst and distilling off unreacted phenols and / or naphthols. To be Examples of phenols used in the reaction include phenol, o-cresol, m-cresol, p-cresol, 2,4-xylenol, 2,6-xylenol, t-butylphenol, o-phenylphenol,
Monohydric phenols such as p-phenylphenol, dihydric phenols such as resorcinol, hydroquinone and catechol, 2-bromophenol, 4-bromophenol, 2-iodophenol, 4-iodophenol, 2
-Chlorophenol, 4-chlorophenol, 2,4-
Dibromophenol, 2,6-bromophenol, 2,
Examples thereof include halogenated phenols such as 4-diiodophenol and 2,6-diiodophenol, and phenylphenols such as o-phenylphenol, m-phenylphenol and p-phenylphenol. Among them, preferable phenols include phenol, o-cresol, m-cresol and p-cresol.

As naphthols, 1-naphthol,
2-naphthol, 5-methyl-1-naphthol, 5-methyl-2-naphthol, 6-ethyl-1-naphthol,
Alkylated naphthols such as 6-ethyl-2-naphthol, halogenated naphthols such as 4-chloro-1-naphthol, 4-chloro-2-naphthol, 4-fluoro-1-naphthol and 4-iodo-2-naphthol, 2,6-
Examples thereof include divalent naphthols such as dihydroxynaphthalene, 1,5-dihydroxynaphthalene, and 1,8-dihydroxynaphthalene. Preferred are 1-naphthol and 2-naphthol.

If the weight average molecular weight of the resin is too small, the solubility in the developing solution is too large to form a pattern, and if it is too large, the solvent solubility is poor.
There is a tendency that it becomes impossible to apply it on the substrate, the solubility in the developing solution becomes small, and an insoluble portion is generated during development, so that a suitable pattern cannot be formed. Therefore, the weight average molecular weight is 500 to 10,
000, preferably 700 to 5,000, and more preferably 1,000 to 3,000. The average molecular weight can be arbitrarily changed by controlling the molar ratio of the phenol and / or naphthols to the sulfur atom or the sulfur chloride. 0.5
˜1.5, preferably 0.55 to 1.0, and more preferably 0.6 to 0.9. In the reaction, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is used, and the amount used is 0.0 / mol in the hydroxide / S molar ratio.
It is 1 to 1.0. The reaction temperature is 100 to 200 ° C., preferably 150 to 180 ° C., and the reaction time is
1 to 30 hours. After completion of the reaction, unreacted phenols and / or naphthols can be distilled off by any method to obtain polythioethers.

When used for the purpose of the present invention, it is important to reduce the content of ionic metal in polythioethers as much as possible. Therefore, a purification step after the reaction is necessary to obtain the polythioethers of the present invention. The method may be any method as long as it can remove the ionic metal, for example, the resin, aromatic hydrocarbons such as toluene, xylene, ketones such as methyl ethyl ketone, methyl isobutyl ketone, amyl alcohol, isoamyl Alcohol, heptanol, 2-heptanol,
Examples include a method of dissolving in alcohols such as octanol and isooctanol, washing with diluted hydrochloric acid, and then washing with water and neutralizing. The polythiophenol (naphthol) thus obtained is used alone or in combination with other alkali-soluble resins as the alkali-soluble component of the photosensitive resin composition of the present invention. Examples of the alkali-soluble component that can be used in combination include so-called novolac resins, phenols and / or naphthols obtained by condensing phenols and / or naphthols such as novolak, cresol novolak, and naphthol novolak with aldehydes and the general formula (2 ) (Chemical Formula 4) obtained by condensation with a xylylene derivative, a so-called xyloc resin, a polymer resin of dicyclopentadiene with phenols or / and naphthols, polyhydroxystyrene and its hydride, styrene-anhydrous Examples include maleic acid copolymers and polymethylmethacrylate.

[0011]

[Chemical 4] (In the formula, X is a hydroxyl group, a halogen atom or a carbon number of 1 to 4
Represents an alkoxy group of

It is a general method to use the resin mixed with the resin of the present invention, and the resin and the resin of the present invention are represented by aldehydes and / or general formula (2)). It can also be used by co-condensing with a xylylene derivative. The ratio is within the range in which the characteristics of the polythioethers of the present invention are represented, and specifically, the polythioethers are contained in an amount of 1 to 100% by weight, preferably 5 to 100% by weight in the total alkali-soluble components. It is a range.

In the present invention, as a photosensitive component which has an ability to suppress the alkali solubility of an alkali-soluble resin used together with an alkali-soluble component and deactivates the ability by light irradiation, known compounds having the above-mentioned ability are used. Can all be used. Specific examples include 1,2-naphthoquinone-2-diazide and its ester, and more specifically, 1,2-naphthoquinone-2-diazide and further its ester,
1,2-naphthoquinone-2-diazide-4 (5) -sulfonic acid chloride and phenol, p-methoxyphenol, dimethylphenol, hydroquinone, p-phenylphenol, α-naphthol, β-naphthol,
2,6-Cihydroxynaphthalene, biphenol, bisphenol A, polyhydroxybenzophenone, 1,3
-Dihydroxy-4,6-bis [(4-hydroxyphenyl-dimethyl) methyl] -benzene, 6,6'-dihydroxy-3,3,3 ', 3'-tetramethyl-biindane, etc. be able to.

Before irradiation with light, these compounds are
It suppresses its alkali solubility by hydrogen-bonding with the hydroxyl group of the alkali-soluble resin, photodecomposes it by irradiating it with light and modifies it to ketene, and further reacts with water in the resist film or air to rapidly dissolve the carboxyl group. It is presumed that the generation of the cation causes a large change in the polarity of the exposed portion, and the solubility in the alkaline aqueous solution is rapidly and significantly increased. In the present invention, it is possible to obtain a so-called positive resist pattern by utilizing these things. In the present invention, the blending amount of this photosensitive component with respect to the alkali-soluble resin is in the range of 1 to 100 parts by weight, preferably 5 to 90 parts by weight, and more preferably 1 to 100 parts by weight of the alkali-soluble resin.
It is in the range of 0 to 70 parts by weight.

The photosensitive resin composition of the present invention is usually dissolved in an organic solvent to be 1 to 50% by weight, preferably 5 to 3%.
A uniform photosensitive resin layer can be formed by applying a 5% solution on the surface of the substrate and drying. For example, an organic solvent solution of the photosensitive resin composition of the present invention is evenly applied onto an arbitrary substrate such as a silicon wafer by a spinner or the like, and this is applied at 50 ° C to 130 ° C.
C., preferably at 80 to 110.degree. C., to form a photosensitive resin composition layer. In order to draw a resist pattern on this coating film, it is irradiated with light through a positive type photomask pattern, and then, an alkali developer, for example, a tetramethylammonium hydroxide aqueous solution having a concentration of 1 to 10% by weight is used. Grade ammonium hydroxide aqueous solution, 1-10 wt% concentration sodium hydroxide aqueous solution,
An arbitrary resist pattern can be obtained by development using an alkali metal hydroxide aqueous solution such as potassium hydroxide aqueous solution or an alkaline aqueous solution such as 1 to 10 wt% choline aqueous solution.

As the organic solvent used at this time, acetone, methyl ethyl ketone, methyl isobutyl ketone,
Ketones such as methyl isoamyl ketone, cyclohexanone, etc., ethylene glycol, diethylene glycol, ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol, dipropylene glycol, propylene glycol monoacetate, dipropylene glycol monoacetate, dipropylene glycol monoacetate monomethyl ether,
Dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monopropyl ether,
Polyhydric alcohols such as dipropylene glycol monobutyl ether and its derivatives, tetrahydrofuran, cyclic ethers such as dioxane, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methoxypropion Examples thereof include esters such as methyl acidate and ethyl ethoxypropionate, and mixtures thereof, but are not limited thereto. In the present invention, a resist pattern is obtained by irradiating the coated surface with light, and the exposure wavelength is preferably g-line (436 mm) or i-line (365 mm). Further, the photosensitive resin composition of the present invention can be used as a so-called negative photoresist by combining with a component which becomes a crosslinking agent when irradiated with light.

[0017]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Synthesis Example 1 225.9 g (2.4 mol) of phenol, 96.2 g (3 mol) of sulfur, and 12.6 sodium hydroxide were placed in a glass reaction container equipped with a stirrer, a thermometer, and a reflux condenser.
g (0.315 mol) was charged, while stirring,
The temperature was raised to 160 ° C. over 2 hours. Since hydrogen sulfide was generated, the generated gas was trapped with an alcal aqueous solution.
After reacting for 6 hours at the same temperature, unreacted phenol was distilled off under reduced pressure. Then, the obtained resin was treated with 2-heptanol 15
It was dissolved in 00 g and washed twice with 1500 g of a 1% hydrochloric acid aqueous solution, and then washed with pure water until it became neutral. 2-Heptanol was distilled off under reduced pressure to obtain 220 g of polythioether represented by the general formula (1) (average n = 5.5). The GPC chart of this resin is shown in (FIG. 1). The OH value of this resin was 125 g / eq.

Synthesis Example 2 118.1 g (0.44 mol) of 1,2-naphthoquinone-2-diazide-4-sulfonic acid chloride and tetrahydroxy were placed in a glass reaction vessel equipped with a stirrer, a thermometer and a reflux condenser. Benzophenone 24.6g (0.1mo
l) was dissolved in 300 g of dimethylacetamide, 42.4 g of triethylamine was added dropwise over 30 minutes with stirring, and the mixture was further stirred for 2 hours, and then the precipitate was filtered off. Then, to the obtained filtrate, 25% 1% aqueous hydrochloric acid solution is added.
0 g was added dropwise to precipitate a reaction product. This product was separated by filtration, washed thoroughly with ion-exchanged water, and dried. GPC
The purity was 100%.

Example 1 As an alkali-soluble resin, 12 g of excellent polythioether in Synthesis Example 1 and, as a photosensitive component, 3.3 g of tetranaphthoquinonediazide sulfonic acid ester obtained in Synthesis Example 2 were mixed with ethyl acetate at a concentration of 35% by weight. A positive resist solution was obtained by preparing a cellosolve acetate solution. This resist solution was spin-coated on a silicon wafer and prebaked in an oven at 80 ° C. for 2 minutes.
The film thickness was 1 μm. This coating film was exposed by i-line using a photomask chart having a positive pattern. After exposure, post bake at 140 ° C for 5 minutes,
It was developed with a 2.3 wt% tetramethylammonium hydroxide aqueous solution for 1 minute to obtain a positive resist pattern. The cross-sectional shape of this resist pattern was observed using a microscope, and it was confirmed that the side surface was vertical and a good pattern was obtained.

Comparative Example 2 The alkali-soluble resin used in Example 1 was replaced with a novolak resin [Mirex # 2000] manufactured by Mitsui Toatsu Chemicals, Inc. 1
A positive type pattern was obtained in the same manner as in Example 1 except that 2 g was used. When the cross section of the resist pattern was observed with a microscope, the side face was slightly inclined, and a good pattern was not obtained.

Examples 2 to 10 A positive type toner was prepared in the same manner as in Example 1 except that the alkali-soluble resin and the photosensitive component in Example 1 were replaced with the compounds shown in Table 1 (Tables 1 and 2). Got the pattern. In addition, φ and B in the table represent the following groups (Formula 5). When the cross section of the resist pattern was observed with a microscope, all the side surfaces were vertical, and a good pattern was obtained. The alkali-soluble resin was synthesized in the same manner as in Synthesis Example 1 using the corresponding phenols and / or naphthols instead of the phenol in Synthesis Example 1. Further, as the photosensitive component, instead of the tetrahydroxybenzophenone of Synthesis Example 2, a corresponding phenol was used,
It was synthesized in the same manner as in Synthesis Example 2.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Chemical 5] Cresol novolac: m-cresol / p-cresol =
7/3, cresol / formalin = 1 / 0.8, a novolak resin having a weight average molecular weight of 9800, Zyloc: manufactured by Mitsui Toatsu Chemicals, Inc., XL-225-3
L

As described above, the photosensitive resin composition containing the polythioether of the present invention is suitable for forming a high-resolution positive pattern, and a conventional novolak resin is used as a base resin. As compared with the photosensitive resin composition described above, a fine pattern having excellent processing accuracy can be obtained. This is in line with the manufacturing of semiconductor devices with higher integration, which is required in such industrial fields, and makes a great contribution to such industrial fields.

[0026]

INDUSTRIAL APPLICABILITY The photosensitive resin composition of the present invention is suitable for obtaining a fine pattern with excellent processing accuracy, and contributes to the production of higher density semiconductor devices.

[Brief description of drawings]

FIG. 1 is a GPC of the polythioether obtained in Synthesis Example 1.
It is a chart.

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-2-251962 (JP, A) JP-A-55-164825 (JP, A) JP-A-51-128342 (JP, A) JP-B-47- 31092 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 75/00-75/08 G03F ⁷ /00-7/42 C08L 81/02 CA (STN) REGISTRY (STN)

Claims (3)

(57) [Claims] 1. A photosensitive resin composition containing an alkali-soluble component and a photosensitive component, wherein a polythioether represented by the following general formula (1) (Chemical formula 1) is an essential component as the alkali-soluble component. 1 to 100% as a photosensitive resin composition. [Chemical 1] (In the formula, A represents a phenol or / and a naphthol residue, and n represents an integer of 0 to 100) 2. The alkali-soluble component is a condensate of phenols or / and naphthols and aldehydes, a phenol or / and naphthols and a xylylene derivative represented by the following general formula (2) A condensate of (In the formula, X is a hydroxyl group, a halogen atom or a carbon number of 1 to 4
Represents an alkoxy group) and a phenol or /
The photosensitive resin composition according to claim 1, which contains at least one selected from the group consisting of a polymer of naphthols and dicyclopentadiene. 3. A method for manufacturing a semiconductor device, which comprises applying the photosensitive resin composition according to claim 1 or 2 onto a substrate to form a coating film, and forming a pattern by light irradiation.