JPH06289612A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To obtain a photosensitive compsn. excellent in storage stability and having coating property by bringing a liquid photosensitive compsn. or a soln. of the resin component which constitutes the photosensitive compsn. into contact with an ion exchange resin and performing ion exchange treatment. CONSTITUTION:A liquid photosensitive compsn. or a soln. of the resin component which constitutes the photosensitive compsn. is brought into contact with an ion exchange resin for ion exchange treatment. The object photosensitive compsn. includes compds. generally called as a resist. As for the ion exchange resin, two kinds of resins, an anion exchange resin and a cation exchange resin, are usually used, and in this method, a cation exchange resin is mainly used to remove metal ions. The ion exchange resin is classified as a macroporous type, gel type, etc., according to kinds of base bodies, and any type of resin can be used. Further, both of a nonwater-base or a water-base resin can be used. The cation exchange resin to be used is a H<+> type as used in a conventional method.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a photosensitive composition,
More specifically, it relates to a photosensitive composition having high performance, good coatability, and excellent storage stability.

[0002]

2. Description of the Related Art Recently, as semiconductor devices have been highly integrated and operated at high speeds, there has been an increasing demand for miniaturization of the devices. In order to meet this requirement, the resist used for lithography is changing from a conventional cyclized polyisoprene-bisazide negative resist to a novolak resin-quinonediazide positive resist, and in response to the demand for forming a finer pattern. For this purpose, a chemically amplified resist using an excimer laser beam as an exposure source and an electron beam resist using an electron beam as an exposure source are used.

Further, as the structure of the semiconductor element becomes complicated, it becomes necessary to form a pattern on a substrate having a step. In this case, a multi-layer resist system is used. In this system, various resins are first applied as a flattening resist material to a semiconductor substrate, and a photosensitive resist layer is formed thereon.

To form a pattern on a semiconductor substrate using a resist, a resist solution is applied on the semiconductor substrate by a spinner or the like to form a resist layer having an appropriate film thickness, and then the remaining solvent is removed. Remove by prebaking. In the multi-layer resist system, first, a planarizing material (planarizing resist) is similarly formed on a semiconductor substrate, and then a resist layer is further formed thereon by the same method as described above.

The substrate on which the resist layer is formed is exposed by a mask pattern transfer method using light, X-rays, or the like, or a drawing method using beam irradiation of electrons, ions, or the like, depending on the type of each resist, and the desired pattern is obtained. A latent image with a pattern is formed. The formed latent image is processed with a developing solution to become a visible image. Using this visible image as a mask, the substrate such as silicon is etched and a desired pattern is transferred to the substrate.

The conventional cyclized polyisoprene-bisazide-based resist was mainly used for the etching of the substrate by wet etching with an aqueous solution of hydrofluoric acid.
Dry etching, which utilizes active species generated during plasma discharge, has been widely used. After etching, the unnecessary resist layer and the flattening resist layer on the substrate are peeled off. In this step, plasma is often used instead of the conventional wet method.

By the way, in general, a resist is a polymer (resin component), a photosensitizer, a dissolution inhibitor, a sensitizer, a storage stabilizer, a plasticizer, a cross-linking agent, a photoacid generator, a dye, and various surface active agents. It contains a component selected from various organic materials, and is usually used as a solution-like photosensitive composition uniformly dissolved in a solvent.

In response to the recent development of photolithography technology as described above, the required performances for resists are becoming more and more severe, and higher performance is required, as well as coating properties and storage properties. It is required to have excellent stability and to prevent the electrical characteristics of the semiconductor from being deteriorated by migration of impurities to the substrate.

For example, in terms of improving the performance of the resist, it is important that the exposure margin and the depth of focus are excellent, and that a fine and good pattern shape can be formed with a process margin. Further, the resist is required to have excellent coatability and to easily form a uniform and flat resist film.
Further, it is required that the photoresist is not deposited during storage of the resist.

The process of forming a pattern on a semiconductor substrate has recently been changed from a conventional wet process to
We are moving to a dry process that does not use solvents,
When processing such as dry etching of the resist layer or the flattening resist layer, peeling with plasma, etc., most of the trace amount of metal contained as impurities in these resists remains on the substrate, so use these substrates. The electrical characteristics of the semiconductor thus formed are significantly deteriorated. Therefore, there is a demand for a resist that does not deteriorate the electrical characteristics of semiconductors.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photosensitive composition which has high performance, good coatability and excellent storage stability. As a result of intensive studies to overcome the above-mentioned problems of the prior art, the inventors have contacted and treated a solution of a photosensitive composition in a solution or a resin as a raw material component thereof with an ion exchange resin, It was found that a photosensitive composition having improved exposure margin and depth of focus, good coatability, and excellent storage stability can be obtained. Further, since the photosensitive composition has a significantly reduced metal content, it does not deteriorate the electrical characteristics of the semiconductor. The present invention has been completed based on these findings.

[0012]

Thus, according to the present invention, a solution-like photosensitive composition or a solution of a resin component constituting the photosensitive composition is brought into contact with an ion exchange resin and subjected to an ion exchange treatment. A photosensitive composition is provided.

The present invention will be described in detail below. (Photosensitive composition) The photosensitive composition of the present invention is
It includes what is generally called a resist. As described above, the resist is, in addition to the polymer (resin component),
It contains components selected from various organic materials such as photosensitizers, dissolution inhibitors, sensitizers, storage stabilizers, plasticizers, crosslinkers, photoacid generators, dyes, various surface active agents, and is usually used as a solvent. It is used as a photosensitive composition in the form of a solution that is uniformly dissolved. Examples of the resist include a positive photoresist, a negative photoresist, an electron beam resist, an X-ray resist, a multi-layer resist and the like.

As the polymer (resin) used in the photosensitive composition, for example, novolac resin, polyvinylphenol resin, polymethylmethacrylate, polyisopropenylketone, poly (olefin sulfone), cyclized polyisoprene, chloromethylated polystyrene. Examples thereof include polystyrene-based polymers such as polymethyl isopropyl ketone, polyhexafluorobutyl methacrylate, polytrifluoroethyl-α-chloroacrylate, nitrocellulose, polysilane, and polyglycidyl methacrylate.

Examples of the photosensitizer include quinonediazide sulfonic acid ester. A quinonediazide sulfonic acid ester can be generally synthesized by an esterification reaction between a compound having an -OH group and a quinonediazidesulfonic acid compound.For example, a quinonediazidesulfonic acid compound is converted into a sulfonyl chloride with chlorosulfonic acid according to a conventional method. It can be obtained by a method of condensing this with a compound having an —OH group.

Specific examples of the photosensitizer include 1,2-benzoquinonediazide-4-sulfonic acid ester whose ester portion is 1,2-naphthoquinonediazide-4-sulfonic acid ester and 1,2-naphthoquinonediazide-5-sulfonic acid ester. Ester, 1,2-naphthoquinonediazide-6-sulfonic acid ester, 2,1-naphthoquinonediazide-4-
Sulfonic acid ester, 2,1-naphthoquinonediazide-
Examples thereof include compounds such as 5-sulfonic acid esters, 2,1-naphthoquinonediazide-6-sulfonic acid esters, and other sulfonic acid esters of quinonediazide derivatives.

The compound having an --OH group used for preparing the photosensitizer is not particularly limited, but examples thereof include cresol, xylenol, resorcin, catechol, hydroquinone, pyrogallol, phloroglucinol, phloroglucide, 2, 3,4-trihydroxybenzophenone, 2,4,4'-trihydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2,2' , 3,4,4'-Pentahydroxyhenzophenone, 2,2 ', 3,4,5'-Pentahydroxybenzophenone, 2,3,3', 4,5'-Pentahydroxybenzophenone, 2,3,3 ', 4, 4',
5'-hexahydroxybenzophenone, 2,3 ',
4,4'5 ', 6-hexahydroxybenzophenone,
Methyl gallate, ethyl gallate, propyl gallate,
2,2-bis (4-hydroxyphenyl) propane,
2,2-bis (2,4-dihydroxyphenyl) propane, 2,2-bis (2,4-dihydroxyphenyl),
2,2-bis (2,3,4-trihydroxyphenyl)
Examples thereof include propane, cresol novolac resin, resorcin-acetone resin, pyrogallol-acetone resin, polyvinylphenol resin, and vinylphenol copolymer. Other components include, for example, dyes,
Examples thereof include surfactants, storage stabilizers, sensitizers, anti-striation agents, plasticizers and the like.

(Organic solvent) The photosensitive composition is usually produced as a solution in which each component is uniformly dissolved in an organic solvent,
It is used. In the present invention, this solution-like photosensitive composition is subjected to ion exchange treatment. Alternatively, the solution of the resin component forming the photosensitive composition may be subjected to ion exchange treatment. When the resin solution is subjected to the ion exchange treatment, it is combined with other components such as a photosensitizer and a surfactant after the treatment to obtain a photosensitive composition.

As the organic solvent, various organic solvents which are generally used when preparing a resist solution can be used. Even if a trace amount of metal is contained in the organic solvent, it is removed when the purification method of the present invention is applied. Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone, cyclohexanone, cyclopentanone, and 2-heptanone; n-propyl alcohol, iso
Alcohols such as propyl alcohol, n-butyl alcohol and cyclohexanol; ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether and dioxane; alcohol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; propyl formate, Esters such as butyl formate, propyl acetate, butyl acetate, cyclopentyl acetate, methyl propionate, ethyl propionate, methyl acetate, ethyl acetate, methyl lactate, ethyl lactate, ethyl pyruvate; cellosolve acetate,
Cellosolve esters such as methyl cellosolve acetate, ethyl cellosolve acetate, propyl cellosolve acetate, butyl cellosolve acetate; ether esters such as methyl methoxypropionate and ethyl ethoxypropionate; propylene glycol, propylene glycol monomethyl ether, prolene glycol monomethyl ether Propylene glycols such as acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether; diethylene glycol such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether Halogenated hydrocarbons such as trichlorethylene; call such as toluene, aromatic hydrocarbons such as xylene; dimethylacetamide, dimethylformamide, such as a polar solvent such as N- methyl acetamide and the like. You may use these individually or in mixture of 2 or more types.

(Treatment with Ion Exchange Resin) There are two types of ion exchange resins, a cation exchange resin and an anion exchange resin. In order to remove metal ions, the cation exchange resin is mainly used. Ion exchange resins include macroporous type and gel type depending on the type of substrate.
Either type can be used. In addition, there are non-aqueous type and aqueous type, but both can be used. The cation exchange resin used is of the H ⁺ type according to the usual method.

The solution type photosensitive composition or the resin solution may be brought into contact with the ion exchange resin by either a flow system or a batch system. Liquid flow velocity (LHSV)
Is not particularly limited, but is preferably 1 to 100 hr.
A range of ^-1 is preferred. The object to be treated may be a solution-shaped photosensitive composition (resist solution) or a solution of a resin which is the main component of the resist. When the resin solution is used as the material to be treated, other necessary components may be added to the purified solution after the ion exchange treatment.

The amount of the ion exchange resin used may be any amount as long as it satisfies the ion exchange capacity calculated from the amount of ions to be removed in advance. When a cation exchange resin is used, it is preferable to perform the ion exchange treatment to the extent that the content of each metal ion in the object to be treated is 5 ppb or less, in order to improve the resist characteristics. After the treatment with the cation exchange resin, a post-treatment is not particularly necessary, but if it is desired to remove anions such as halogen ions in addition to the metal ions, the treatment may be performed with the anion exchange resin.

[0023]

The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to these examples. Parts and% are based on weight unless otherwise specified.

Example 1 A resin solution prepared by dissolving 30 parts of novolak resin in 100 parts of ethyl cellosolve acetate was passed through a packed column filled with a porous strongly acidic cation exchange resin converted into H ⁺ form. . The liquid hourly space velocity (LHSV) at this time was 10 hr ⁻¹ . Table 1 shows the metal contents before and after passing through the packed column. The metal content is
It was measured and analyzed by metal board flameless atomic absorption spectrometry.

[0025]

[Table 1]

A photosensitive composition was prepared by adding a photosensitizer and a surfactant to the resin solution thus treated. The characteristics of the obtained photosensitive composition and the photosensitive composition obtained by not treating the resin solution as described above were compared, and the former was more advantageous than the latter in terms of exposure margin and focal depth. And showed good performance, good coatability, no precipitation of the photosensitizer for at least one year at room temperature, and excellent storage stability.

Example 2 A resin solution prepared by dissolving 30 parts of novolac resin in 100 parts of ethyl lactate was passed through a packed column filled with a porous strong acid cation exchange resin converted into H ⁺ type. The liquid hourly space velocity (LHSV) at this time is 10
It was hr ^-1 . Table 2 shows the metal contents before and after passing through the packed column.

[0028]

[Table 2]

A photosensitive composition was prepared by adding a photosensitizer and a surfactant to the resin solution thus treated. The characteristics of the obtained photosensitive composition and the photosensitive composition obtained by not treating the resin solution as described above were compared, and the former was more advantageous than the latter in terms of exposure margin and focal depth. And showed good performance, good coatability, no precipitation of the photosensitizer for at least one year at room temperature, and excellent storage stability.

[Example 3] Polyvinylphenol resin 2
A resin solution prepared by dissolving 0 part in 100 parts of ethyl cellosolve acetate was passed through a packed column filled with a porous strong acid cation exchange resin converted into an H ⁺ form. The liquid hourly space velocity (LHSV) at this time was 10 hr ⁻¹ . Table 3 shows the metal contents before and after passing through the packed column.

[0031]

[Table 3]

A photosensitive composition was prepared by adding a photosensitizer, a surfactant and the like to the resin solution thus treated. The characteristics of the obtained photosensitive composition and the photosensitive composition obtained by not treating the resin solution as described above were compared, and the former was more advantageous than the latter in terms of exposure margin and focal depth. And showed good performance, good coatability, no precipitation of the photosensitizer for at least one year at room temperature, and excellent storage stability.

Example 4 An experiment was conducted in the same manner as in Example 3 except that 100 parts of ethyl cellosolve acetate of Example 3 was replaced with 100 parts of ethyl lactate. Table 4 shows the metal contents before and after passing through the packed column.

[0034]

[Table 4]

[Embodiment 5] A positive resist for g-line was changed to H
^The treatment was carried out through a packed column packed with a porous strongly acidic cation exchange resin converted into ⁺ type. The liquid hourly space velocity (LHSV) at this time was 15 hr ⁻¹ . Table 5 shows the metal contents before and after passing through the packed column.

[0036]

[Table 5]

The g-line positive resist thus treated has excellent characteristics such as an exposure margin and a depth of focus as compared with untreated g-line positive resist, and has good coatability. At room temperature, there was no precipitation of the photosensitizer for at least one year and the storage stability was excellent.

[Embodiment 6] A positive resist for i-line was changed to H
^The treatment was carried out through a packed column packed with a porous strongly acidic cation exchange resin converted into ⁺ type. The liquid hourly space velocity (LHSV) at this time was 10 hr ⁻¹ . Table 6 shows the metal contents before and after passing through the packed column.

[0039]

[Table 6]

The i-line positive resist thus treated has excellent characteristics such as an exposure margin and a depth of focus as compared with untreated i-line positive resist, and has good coatability. At room temperature, there was no precipitation of the photosensitizer for at least one year, and the storage stability was excellent.

[0041]

EFFECTS OF THE INVENTION According to the present invention, there is provided a photosensitive composition having high performance in terms of exposure margin and depth of focus, good coatability, and excellent storage stability. Further, the photosensitive composition of the present invention has a significantly reduced metal content, and therefore does not deteriorate the electrical characteristics of the semiconductor.

Claims (1)

[Claims] 1. A photosensitive composition comprising a solution-shaped photosensitive composition or a solution of a resin component constituting the photosensitive composition, which is brought into contact with an ion exchange resin and subjected to an ion exchange treatment.