JP2003207894A - Photosensitive resin composition and positive pattern forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat resistant resin composition capable of forming a pattern with an aqueous alkali solution and having positive photosensitivity and to provide a heat resistant pattern forming method using the same. <P>SOLUTION: The photosensitive resin composition is characterized in that is comprises (A) a photosensitive polymer having a repeating unit of formula (1) (where R<SP>1</SP>and R<SP>2</SP>are each an aromatic group or an organic group comprising a plurality of aromatic rings bonded through a single bond or -O-, -CO-, -SO<SB>2</SB>-, -CH<SB>2</SB>- or -C(CF<SB>3</SB>)<SB>2</SB>-; R<SP>3</SP>is alkyl; and n is an integer of ≥1), (B) a photoacid generator which is converted to an acidic compound under an actinic ray and (C) a solvent. In the positive pattern forming method, a coating film of the composition is exposed, developed with an aqueous alkali solution and imidated. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyimide-based photosensitive resin composition used as an electric / electronic insulating material in the production of semiconductor devices and the like and a method for forming a positive pattern thereof. The object is an insulating protective film formed on the surface of a semiconductor element such as an IC or LSI, and is applied to those requiring processing of a fine pattern.

[0002]

2. Description of the Related Art Conventionally, as a heat-resistant polymer composition having photosensitivity, a tertiary amine compound having an acryl or methacryl group is introduced into a polyamic acid, which is a precursor of polyimide, by an ionic bond. There are a type (JP-A-54-145794) and a type (JP-A-49-115541) in which a compound having an acryl or methacryl group is introduced through an ester bond. All of them have a negative pattern forming ability and are used as a protective film for electronic materials such as semiconductors. However, the above-mentioned photosensitive resin must use an organic solvent having high polarity at the time of pattern formation, so that industrial waste,
It is not preferable in terms of environmental problems, and these resins are
It was impossible to form a fine pattern because of its high swelling property with respect to the organic solvent.

To address these problems, a positive type photosensitive resin has been proposed in which a diazonaphthoquinone compound is added as a photosensitizer to polybenzoxazole having heat resistance equivalent to that of a polyimide resin (JP-A-56-27140). This positive-type photosensitive resin has the advantage that it is possible to form a pattern in an alkaline aqueous solution and therefore does not require the use of an organic solvent. Furthermore, since this resin has a low swelling property in an alkaline aqueous solution, it is relatively A fine pattern can be obtained. However, this positive-type photosensitive resin has a drawback that the dimensional control of the pattern is poor in the pattern on a large wafer because the difference in solubility between the exposed portion and the unexposed portion is low.

However, with the rapid development of semiconductor technology in recent years, the required characteristics of the related materials, especially the pattern forming material, have become more severe. As a material for semiconductor protective film, while it has the same film characteristics as the polyimide resin that is already popular,
Further, a resolution comparable to that of a resist material is required, and in that sense, development of a positive photosensitive resin composition capable of high resolution is strongly awaited.

[0005]

The object of the present invention is to solve the above-mentioned conventional drawbacks, to enable pattern formation with an alkaline aqueous solution, and to provide a heat-resistant resin composition having positive photosensitivity, and The present invention provides a method for forming a heat resistant pattern using a photosensitive resin composition.

[0006]

DISCLOSURE OF THE INVENTION As a result of earnest studies to achieve the above object, the present inventor has found a novel positive photosensitive resin composition having a composition described below and a method for forming a positive pattern thereof. The present invention has been completed by finding that the above object can be achieved by adopting the method.

That is, the present invention is (A) a photosensitive polymer represented by the following general formula,

[Chemical 2] (In the formula, R ¹ is a tetravalent aromatic group, a tetravalent organic group in which a plurality of aromatic rings are single-bonded, or a plurality of aromatic rings are —O—, —CO—, —SO. ₂ -, - CH ₂ - or -
A tetravalent organic group bonded by C (CF ₃ ) ₂
² is a divalent aromatic group, a divalent organic group in which a plurality of aromatic rings are single-bonded, or a plurality of aromatic rings are —O—, —CO
_{-, - SO 2 -, -} CH 2 - or -C (CF _{3) 2}
A divalent aromatic group bonded by-, R ³ is an alkyl group, and n is an integer of 1 or more) (B) A photoacid generator that is converted into an acidic compound by actinic rays and (C ) A photosensitive resin composition comprising a solvent. A positive pattern forming method is characterized in that a coating film of this photosensitive resin composition is formed on a substrate, exposed to light, developed using an alkaline aqueous solution, and then imidized.

The present invention will be described in detail below.

The method for synthesizing the photosensitive polymer composition (A) used in the present invention is carried out by the following procedure.

(1) R ¹ shown in the general formula of the above chemical formula 2
A polycondensation reaction step of an acid dianhydride having a skeleton and a diamine compound having an R ² skeleton, (2) a reaction step of introducing an —OCH (CH ₃ ) OR ³ skeleton into the composition subjected to the polycondensation reaction, (3)
Preparation process of photo acid generator and resin solvent.

First, the synthesizing method will be described in the order of steps (1) to (3).

(1) Polycondensation reaction step of an acid dianhydride having an R ¹ skeleton and a diamine compound having an R ² skeleton in the formula (2): The acid component used as the R ¹ skeleton in the present invention is, for example, , Pyromellitic acid, 3,3 ', 4,4'-biphenyltetracarboxylic acid, 2,3,3', 4'-biphenyltetracarboxylic acid, 3,3 ', 4,4'-benzophenonetetracarboxylic acid, 4,4'-oxydiphthalic acid, 3,
3 ', 4,4'-diphenylsulfone tetracarboxylic acid, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane, 2,3,6,7-naphthalene tetracarboxylic acid, 1,2,5 , 6-naphthalene tetracarboxylic acid, 1,4,5,8-naphthalene tetracarboxylic acid, 1,2,3,4-cyclobutane tetracarboxylic acid,
1,2,3,4-butanetetracarboxylic acid, 1,2,
4,5-cyclopentane tetracarboxylic acid, 1,2,
4,5-cyclohexanetetracarboxylic acid, 3,3 ',
4,4'-bicyclohexyl tetracarboxylic acid, 2,
3,5-tricarboxycyclopentyl acetic acid, 3,4-
Examples thereof include dicarboxy-1,2,3,4-tetrahydronaphthalene-1-succinic acid and the anhydrides thereof, and these can be used alone or in combination.

R ² of the polymer composition (A) used in the present invention
Examples of the skeleton diamine component include m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,6-diaminotoluene, 3,5-diaminotoluene, 1- Methoxy-2,4-diaminobenzene, 1,4-diamino-
2-methoxy-5-methylbenzene, 1,3-diamino-4,6-dimethylbenzene, 3,5-diaminobenzoic acid, 2,5-diaminobenzoic acid, 1,2-diaminonaphthalene, 1,4-diamino Naphthalene, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-
Diaminonaphthalene, 1,8-diaminonaphthalene,
2,3-diaminonaphthalene, 2,6-diaminonaphthalene, 1,4-diamino-2-methylnaphthalene, 1,
5-diamino-2-methylnaphthalene, 1,3-diamino-2-phenylnaphthalene, 2,2-bis (4-aminophenyl) propane, 1,1-bis (4-aminophenyl) ethane, 4,4 ′ -Diaminodiphenylmethane,
3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3 ', 5,5'-tetramethyl-4,4'-
Diaminodiphenylmethane, 3,3'-dimethyl-5,
5'-diethyl-4,4'-diaminodiphenylmethane, 3,3 ', 5,5'-tetraethyl-4,4'-diaminodiphenylmethane, 4,4'-methylenebis (cyclohexylamine), 4,4'-methylenebis (3,
3-dimethyl-cyclohexylamine), 2,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone,
4,4'-diaminobenzanilide, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, bis (4-aminophenyl) diethylsilane, bis (4-
Aminophenyl) diphenylsilane, bis (4-aminophenyl) -N-methylamine, bis (4-aminophenyl) -N-phenylamine, 3,3′-diaminobenzophenone, 4,4′-diaminobenzophenone, 2,
6-diaminopyridine, 3,5-diaminopyridine,
4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3 '-Dihydroxy-4,4'-diaminobiphenyl, o-toluidine sulfone, 4,4 '
-Bis (4-aminophenoxy) biphenyl, 2,2-
Bis [4- (4-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-amino) Phenoxy)
Phenyl] sulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 9,10-bis (4-aminophenyl)
Anthracene, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis (3-aminophenyl) hexafluoropropane, 1,1-bis (4-aminophenyl) -1-phenyl-2,2,2-trifluoroethane, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, 2,2-bis (3
-Amino-4-methylphenyl) hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane and the like can be mentioned, and these can be used alone or in combination of two or more. it can. Further, these compounds are preferably used in an equimolar amount to the ester compound, but the purpose of use and the final viscosity,
It can be used in a range of 0.5 to 1.5 times mol in accordance with the molecular weight.

Examples of the polymerization solvent for the resin composition used in the present invention include aprotic polar solvents such as N-methylpyrrolidone, N, N'-dimethylacetamide, N, N'-dimethylformamide, cyclohexanone and cyclohexanone. Pentanone and the like are used, and these can be used alone or in combination of two or more.

R above¹Acid component with skeleton and R²Skeleton
For example, the polycondensation reaction of ¹Acid with a skeleton
Water and R²Diamine having a skeleton is used with the above reaction solvent.
Preferably at room temperature.

(2) --OCH to the composition subjected to polycondensation reaction
(CH ₃ ) OR ³ skeleton introduction reaction step, introduced into the above polycondensed composition with a hemiacetal ester bond to give —O
Examples of the compound forming the CH (CH ₃ ) OR ³ skeleton include alkyl vinyl ether compounds, such as ethyl vinyl ether, propyl vinyl ether, isopropyl vinyl ether, tert-butyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, tert-
Examples thereof include pentyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, dodecyl vinyl ether, hexadecyl vinyl ether, isooctyl vinyl ether and octadecyl vinyl ether, and these can be used alone or in combination of two or more.

The hemiacetal esterification reaction between the composition subjected to the polycondensation reaction and the alkyl vinyl ether compound is preferably carried out at 40 to 50 ° C. for 5 to 10 hours using the above reaction solvent.

(3) Step of preparing photoacid generator and resin solvent.

The photoacid generator (C) used in the present invention is a substance which produces a Lewis acid or a cation species by an actinic ray such as ultraviolet rays, and in recent years, it is a resist for forming a fine pattern of a semiconductor integrated circuit (commonly called a chemically amplified resist). Is often used in. Examples of the photoacid generator include the following chemical formulas 3 to 1
The compound shown in 1 is mentioned.

[0020]

[Chemical 3]

[Chemical 4]

[Chemical 5]

[Chemical 6]

[Chemical 7]

[Chemical 8]

[Chemical 9]

[Chemical 10]

[Chemical 11] Next, a method for forming a positive pattern with the photosensitive resin composition obtained by the present invention will be described.

Considering application to a semiconductor device, first, the resin composition is coated on a target wafer using a spin coater, and then the coating film is heat-treated at 90 to 130 ° C. 365 nm, 436n are transmitted through a mask having a pattern drawn on the obtained coating film.
Irradiate active ultraviolet rays such as m. By the catalytic reaction of the acid generated by this exposure, -OCH of the polymer side chain is
(CH ₃₎ in order to accelerate the deprotection reaction of the OR ³ skeletal sites, coating is performed a heat treatment of about 100 ° C. as above 90 to 130 ° C.. Next, this coating film is treated with an alkaline aqueous solution, for example, an inorganic alkaline aqueous solution such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate or ammonia, a primary amine such as ethylamine or n-propylamine, diethylamine or di-n-propyl. Use secondary amines such as amines, tertiary amines such as triethylamine and methyldimethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, and aqueous solutions of quaternary amines such as tetramethylammonium hydroxide and tetraethylammonium hydroxide. Then, only the actinic ray irradiation portion is dissolved and developed, and rinsed with pure water.
As a developing method, a method such as spraying, paddle, dipping, and ultrasonic wave can be considered. As a result, a desired positive pattern can be obtained on the target wafer.
Further, by heat-treating this coating film, this resin composition can be imidized to form a polyimide film having excellent film characteristics.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below based on Examples.

Example 1 First, a reaction flask equipped with a nitrogen introducing tube was placed in a 3,3 ',
4,4'-biphenyltetracarboxylic dianhydride 11
7.9 g, 4,4'-diaminodiphenyl ether 7
2.2 g, 1,3-bis (γ-aminopropyl) -1,
1,3,3-tetramethyldisiloxane 9.96 g and N-methyl-2-pyrrolidone 800.0 g are added,
The reaction was carried out at room temperature for 3 hours. After completion of the reaction, 80 g of ethyl vinyl ether was added and the reaction was carried out at 45 ° C for 5 hours. After the reaction was completed, the temperature was returned to room temperature.

Next, 10 parts by weight of N-hydroxynaphthalimide p-toluenesulfonate was dissolved in 100 parts by weight of the obtained polyimide precursor / N-methyl-2-pyrrolidone solution to obtain a photosensitive resin composition. .

A 6-inch silicon wafer was coated with this photosensitive resin composition using a spin coater, and 100
Film thickness 10 μm by drying on a bake plate at ℃
A coating film of A line / space pattern of 300 mj / c is formed on the surface of this coating film by using a mirror projection.
It was exposed with an exposure amount of m ² . Then 2.38% TMAH
Static puddle development was performed for 60 seconds in an aqueous solution of (tetramethylammonium hydride) and rinsed with pure water. When the obtained positive pattern was observed with an optical microscope,
It was found that the resolution was up to 3.0 μm line / space. Further, this relief pattern was sequentially subjected to heat treatment at 150 ° C. for 1 hour, 250 ° C. for 1 hour, and 350 ° C. for 1 hour to complete imidization of the coating film. This imide pattern is firmly adhered to the silicon wafer,
It did not peel off even in a normal tape peeling test.

Example 2 First, in a reaction flask equipped with a nitrogen introducing tube, 3,3 ',
4,4'-biphenyltetracarboxylic dianhydride 11
7.9 g, 4,4'-diaminodiphenyl ether 7
2.2 g, 1,3-bis (γ-aminopropyl) -1,
1,3,3-tetramethyldisiloxane 9.96 g and N-methyl-2-pyrrolidone 800.0 g are added,
The reaction was carried out at room temperature for 3 hours. After completion of the reaction, 110 g of isopropyl vinyl ether was added and the reaction was carried out at 45 ° C. for 5 hours. After the reaction was completed, the temperature was returned to room temperature.

Next, 10 parts by weight of N-hydroxynaphthalimide p-toluenesulfonate was dissolved in 100 parts by weight of the obtained polyimide precursor / N-methyl-2-pyrrolidone solution to obtain a photosensitive resin composition. .

This photosensitive resin composition was coated on a 6-inch silicon wafer using a spin coater,
Film thickness 10 μm by drying on a bake plate at ℃
A coating film of A line / space pattern of 300 mj / c is formed on the surface of this coating film by using a mirror projection.
It was exposed with an exposure amount of m ² . Then 2.38% TMAH
Static puddle development was performed for 60 seconds in an aqueous solution of (tetramethylammonium hydride) and rinsed with pure water. When the obtained positive pattern was observed with an optical microscope,
It was found that the resolution was up to 3.0 μm line / space. Further, this relief pattern was sequentially subjected to heat treatment at 150 ° C. for 1 hour, 250 ° C. for 1 hour, and 350 ° C. for 1 hour to complete imidization of the coating film. This imide pattern is firmly adhered to the silicon wafer,
It did not peel off even in a normal tape peeling test.

Example 3 First, 136.8 g of 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane, 55.5 g of 4,4'-diaminodiphenyl ether were placed in a reaction flask equipped with a nitrogen introducing tube. , 3-bis (γ-aminopropyl)
-1,1,3,3-tetramethyldisiloxane 7.66
g and 800.0 g of γ-butyrolactone were added, and the mixture was reacted at room temperature for 3 hours. After completion of the reaction, 85.0 g of isopropyl vinyl ether was added and the reaction was carried out at 45 ° C. for 5 hours. After the reaction was completed, the temperature was returned to room temperature.

Next, 10 parts by weight of N-hydroxynaphthalimide p-toluenesulfonate was dissolved in 100 parts by weight of the obtained polyimide precursor / γ-butyrolactone solution to obtain a photosensitive resin composition.

A 6-inch silicon wafer was coated with this photosensitive resin composition using a spin coater,
Film thickness 10 μm by drying on a bake plate at ℃
A coating film of A line / space pattern of 300 mj / c is formed on the surface of this coating film by using a mirror projection.
It was exposed with an exposure amount of m ² . Then 2.38% TMAH
Static puddle development was performed for 20 seconds in an aqueous solution of (tetramethylammonium hydride) and rinsed with pure water. When the obtained positive pattern was observed with an optical microscope,
It was found that the resolution was up to 3.0 μm line / space. Further, this relief pattern was sequentially subjected to heat treatment at 150 ° C. for 1 hour, 250 ° C. for 1 hour, and 350 ° C. for 1 hour to complete imidization of the coating film. This imide pattern is firmly adhered to the silicon wafer,
It did not peel off even in a normal tape peeling test.

Example 4 First, 136.8 g of 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane, 55.5 g of 4,4'-diaminodiphenyl ether were placed in a reaction flask equipped with a nitrogen introducing tube. , 3-bis (γ-aminopropyl)
-1,1,3,3-tetramethyldisiloxane 7.66
g and 800.0 g of γ-butyrolactone were added, and the mixture was reacted at room temperature for 3 hours. After completion of the reaction, 85.0 g of tert-butyl vinyl ether was added and the reaction was carried out at 45 ° C for 5 hours. After the reaction was completed, the temperature was returned to room temperature.

Next, 10 parts by weight of N-hydroxynaphthalimide p-toluenesulfonate was dissolved in 100 parts by weight of the obtained polyimide precursor / γ-butyrolactone solution to obtain a photosensitive resin composition.

A 6-inch silicon wafer was coated with this photosensitive resin composition using a spin coater, and 100
Film thickness 10 μm by drying on a bake plate at ℃
A coating film of A line / space pattern of 300 mj / c is formed on the surface of this coating film by using a mirror projection.
It was exposed with an exposure amount of m ² . Then 2.38% TMAH
Static puddle development was performed for 20 seconds in an aqueous solution of (tetramethylammonium hydride) and rinsed with pure water. When the obtained positive pattern was observed with an optical microscope,
It was found that the resolution was up to 3.0 μm line / space. Further, this relief pattern was sequentially subjected to heat treatment at 150 ° C. for 1 hour, 250 ° C. for 1 hour, and 350 ° C. for 1 hour to complete imidization of the coating film. This imide pattern is firmly adhered to the silicon wafer,
It did not peel off even in a normal tape peeling test.

[0035]

EFFECT OF THE INVENTION The photosensitive polymer composition of the present invention can be used as a moisture resistant protective film of a semiconductor device and can obtain a high resolution positive pattern,
Not only has it become possible to put the device into practical use, which has been difficult to develop in the past, but it is also possible to eliminate the organic solvent, which has been used enormously, because it is possible to form a pattern with an alkaline aqueous solution. . In addition, the photosensitive polymer resin composition of the present invention can achieve higher resolution and higher contrast than ever by using a novel photosensitive system.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H025 AA02 AA10 AA20 AB16 AC04                       AC08 AD03 BE00 BE10 BG00                       CB25 CB41 CC03 FA17 FA29                 2H096 AA25 BA11 EA05 GA08 HA01                 4J043 PA02 PC076 PC116 QB31                       QC16 RA08 RA23 SA06 SA32                       SA42 SA47 SA54 SA62 SA72                       SA82 SB01 SB02 TA14 TA22                       TA32 TB01 TB02 UA032                       UA041 UA042 UA052 UA121                       UA122 UA131 UA132 UA251                       UA261 UA262 UB011 UB061                       UB121 UB291 UB301 UB302                       UB311 VA021 VA022 VA041                       VA042 XA13 ZB22

Claims (2)

[Claims] 1. A photosensitive polymer having (A) the following repeating unit: (In the formula, R ¹ is a tetravalent aromatic group, a tetravalent organic group in which a plurality of aromatic rings are single-bonded, or a plurality of aromatic rings are —O—, —CO—, —SO. ₂ -, - CH ₂ - or -
A tetravalent organic group bonded by C (CF ₃ ) ₂
² is a divalent aromatic group, a divalent organic group in which a plurality of aromatic rings are single-bonded, or a plurality of aromatic rings are —O—, —CO
_{-, - SO 2 -, -} CH 2 - or -C (CF _{3) 2}
A divalent aromatic group bonded by-, R ³ is an alkyl group, and n is an integer of 1 or more) (B) A photoacid generator that is converted into an acidic compound by actinic rays and (C ) A photosensitive resin composition comprising a solvent. 2. A positive pattern formation comprising forming a coating film of the photosensitive resin composition according to claim 1 on a substrate, exposing it, developing it using an aqueous alkali solution, and then imidizing it. Method.