JPH06186744A - Photosensitive resin composition - Google Patents

Abstract

PURPOSE:To easily provide a coating film not causing repelling, free from pinholes and excellent in smoothness by using a photosensitive resin compsn. consisting of a specified polyamic ester and a specified lactic ester. CONSTITUTION:This photosensitive resin compsn. consists of a polyamic ester represented by formula I and a lactic ester represented by formula II. In the formula I, R1 is a tri- or tetravalent org. group, R<2> is a divalent org. group, R3 is -R5-[-O-C(=O)-C(-R5)=CH2]p, R4 is -R5-[-O-C(=O)-C-(-R6)=CH2]p, -CH3 or -C2H5, R5 is a di- to hexavalent org. group, R6 is H or -CH3, each of (l), (m) and (n) is 0 or 1, (p) is an integer of 1-5, x>0%, y<100%, 0<z<80% and x+y+z=100%.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention easily forms a coating film having excellent smoothness and pinholes by using an organic solvent when the coating film is formed on a support such as a silicon wafer by spin coating or the like. The present invention relates to a photosensitive resin composition that can be used.

[0002]

2. Description of the Related Art Conventionally, a polyimide having excellent heat resistance and excellent electrical insulation and mechanical strength has been used for a surface protective film and an interlayer insulating film of a semiconductor element. Recently, a technique for imparting photosensitivity to polyimide itself has been attracting attention in order to simplify the complicated process. For example, the following formula

[0003]

[Chemical 2]

There is known a polyimide precursor composition (for example, Japanese Examined Patent Publication No. 55-41422) in which a photosensitive group is provided with an ester group having a structure as shown in FIG. All of these are dissolved in a suitable organic solvent, applied in a varnish state, dried, and then irradiated with ultraviolet rays through a photomask,
A polyimide coating is formed by developing and rinsing to obtain a desired pattern and further heat treatment.

The use of a photosensitized polyimide not only has the effect of simplifying the pattern forming process, but it is also safe and excellent in pollution because it does not require the use of a highly toxic etching solution. It is expected that sexualization will become an even more important technology in the future. However, when such a conventional photosensitizing technique is applied, when a photosensitive polyimide resin composition having a photosensitive group introduced by an ester group is applied to a silicon wafer or the like applied to a semiconductor or the like, repelling and pinholes are likely to occur. It was a problem. For this reason,
Conventionally, it has been proposed to use a solvent as a mixed system or to add various surface smoothing agents.

[0006]

An object of the present invention is to specify a polyamic acid ester in which a mono- or polyfunctional photosensitive group and a lower alcohol are introduced in the form of an ester bond to the carboxyl group in the polyamic acid. Disclosed is a photosensitive resin composition in which cissing, pinholes, etc. do not occur when applied to a silicon wafer or the like by dissolving it in a certain amount in a lactate ester, and a coating film having excellent smoothness can be easily obtained. is there.

[0007]

The present invention is a photosensitive resin composition comprising a polyamic acid ester represented by the formula (1) and a lactic acid ester represented by the formula (2).

[0008]

[Chemical 3]

[0009] _{CH 3 -CH (OH) -COO-} R 7 (2) wherein _{R 7,: CH 3, C} 2 H 5, C 3 H 7 or C ₄ H ₉

[0010]

The polyamic acid ester represented by the formula (1) used in the present invention exhibits high reactivity, and the cured product has good heat resistance, mechanical properties and electrical properties.

In the formula (1), R ₁ is introduced from a compound having a trivalent or tetravalent organic group, and usually aromatic tetracarboxylic acid or its derivative and aromatic tricarboxylic acid or its derivative are mainly used. To be done. For example, trimellitic anhydride, pyromellitic dianhydride, benzene-1,2,3,4
-Tetracarboxylic acid dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic acid dianhydride, 2,2', 3,3'-benzophenone tetracarboxylic acid dianhydride, 2,3,3 ' , 4'-benzophenone tetracarboxylic dianhydride, naphthalene-2,3,6,7-tetracarboxylic dianhydride, naphthalene-1,2,5,6-tetracarboxylic dianhydride, naphthalene-1, 2,4,5-Tetracarboxylic acid dianhydride, naphthalene-1,4,5,8-tetracarboxylic acid dianhydride, naphthalene-1,2,6,7-tetracarboxylic acid dianhydride, 4,8 -Dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6, 7-hexahydronaphthalene-2,3,6,7-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,
4,5,8-Tetracarboxylic acid dianhydride, 2,7-Dichloronaphthalene-1,4,5,8-tetracarboxylic acid dianhydride, 2,3,6,7-Tetrachloronaphthalene-1,4 , 5,8-Tetracarboxylic acid dianhydride, 1,4,5,8-Tetrachloronaphthalene-2,3,6,7-tetracarboxylic acid dianhydride, 3,3 ', 4,4'-diphenyl Tetracarboxylic acid dianhydride, 2,2 ', 3,3'-diphenyltetracarboxylic acid dianhydride, 2,3,3', 4'-diphenyltetracarboxylic acid dianhydride, 3,3 ", 4, 4 "-p-terphenyltetracarboxylic dianhydride, 2,2", 3,3 "-p-terphenyltetracarboxylic dianhydride, 2,3,3", 4 "-p-terphenyltetra Carboxylic dianhydride, 2,2-bis (2,3-dicarboxyphenyl) -propane dianhydride, 2,2-bis (3,4-dicarboxyphenyl)-
Propane dianhydride, bis (2,3-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, Bis (3,4-dicarboxyphenyl) methane dianhydride, bis (2,3-dicarboxyphenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, perylene-2,3,8,9-tetracarboxylic dianhydride, Perylene-3,4,9,10-tetracarboxylic dianhydride, perylene
-4,5,10,11-tetracarboxylic dianhydride, perylene-5,6,
11,12-Tetracarboxylic acid dianhydride, phenanthrene-1,
2,7,8-Tetracarboxylic acid dianhydride, phenanthrene-1,
2,6,7-Tetracarboxylic acid dianhydride, phenanthrene-1,
2,9,10-Tetracarboxylic acid dianhydride, cyclopentane-1,
2,3,4-tetracarboxylic dianhydride, pyrazine-2,3,5,6-
Examples include, but are not limited to, tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, and the like. Not something. Further, in use, one kind or a mixture of two or more kinds may be used.

In the formula (1), R ₂ is a divalent organic group, and an aromatic diamine and / or its derivative is usually used for its introduction. For example, m-phenylene-diamine, 1-isopropyl-2,4-phenylene-diamine, p-phenylene-diamine, 4,4'-diamino-diphenylpropane, 3,3'-diamino-diphenylpropane, 4,4'- Diamino-diphenylethane, 3,3'-diamino-diphenylethane, 4,4'-diamino-diphenylmethane, 3,3'-diamino-diphenylmethane, 4,4'-diamino-diphenylsulfide, 3,3'-diamino- Diphenyl sulfide, 4,4'-diamino-diphenyl sulfone, 3,3'-diamino-diphenyl sulfone, 4,
4'-diamino-diphenyl ether, 3,3'-diamino-diphenyl ether, benzidine, 3,3'-diamino-biphenyl, 3,3'-dimethyl-4,4'-diamino-biphenyl, 3,3'-
Dimethoxy-benzidine, 4,4 "-diamino-p-terphenyl, 3,3" -diamino-p-terphenyl, bis (p-amino-cyclohexyl) methane, bis (p-β-amino-t-butylphenyl ) Ether, bis (p-β-methyl-δ-aminopentyl)
Benzene, p-bis (2-methyl-4-amino-pentyl) benzene, p-bis (1,1-dimethyl-5-amino-pentyl) benzene, 1,5-diamino-naphthalene, 2,6-diamino- Naphthalene, 2,4-bis (β-amino-t-butyl) toluene, 2,4-diamino-toluene, m-xylene-2,5-diamine, p-xylene
-2,5-diamine, m-xylylene-diamine, p-xylylene
-Diamine, 2,6-diamino-pyridine, 2,5-diamino-pyridine, 2,5-diamino-1,3,4-oxadiazole, 1,4-
Diamino-cyclohexane, piperazine, methylene-diamine, ethylene-diamine, propylene-diamine, 2,2-
Dimethyl-propylene-diamine, tetramethylene-diamine, pentamethylene-diamine, hexamethylene-diamine, 2,5-dimethyl-hexamethylene-diamine, 3-methoxy-hexamethylene-diamine, heptamethylene-diamine, 2,5- Dimethyl-heptamethylene-diamine, 3-methyl-heptamethylene-diamine, 4,4-dimethyl-heptamethylene-diamine, octamethylene-diamine, nonamethylene-diamine, 5-methyl-nonamethylene-diamine, 2,5
-Dimethyl-nonamethylene-diamine, decamethylene-diamine, 1,10-diamino-1,10-dimethyl-decane, 2,11-diamino-dodecane, 1,12-diamino-octadecane, 2,12-
Diamino-octadecane, 2,17-diamino-icosane,
Examples include diaminosiloxane, 2,6-diamino-4-carboxylic benzene, 3,3'-diamino-4,4'-dicarboxylic benzidine, and 1,3-bis (3-aminopropyl) tetramethyldisiloxane. However, the present invention is not limited to these. Also, when using, even one type is 2
It may be a mixture of more than one kind.

In the formula (1), R ₃ is a photosensitive group having 1 to 5 acrylic (methacrylic) groups, R ₄ is a photosensitive group having 1 to 5 acrylic (methacrylic) groups or a methyl group, It is an ethyl group. When the acryl (methacryl) group is 0 in R ₃ and R ₄ , a crosslinked structure cannot be obtained, which is not preferable. Further, 6 or more acryl (methacryl) groups are not preferable because not only they are industrially difficult to produce but also the compatibility is lowered because the molecular weight becomes large. As the compound for introducing R ₃ and R ₄ , for example, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol acrylate dimethacrylate, pentaerythritol diacrylate methacrylate, dipentaerythritol pentaacrylate, dipentaerythritol pentamethacrylate, Glycerol diacrylate, glycerol dimethacrylate, glycerol acrylate methacrylate, trimethylolpropane diacrylate, 1,3-diacryloylethyl
-5-hydroxyethyl isocyanurate, 1,3-dimethacrylate-5-hydroxyethyl isocyanurate, ethylene glycol modified pentaerythritol triacrylate, propylene glycol modified pentaerythritol triacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate , 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, glycidyl methacrylate, glycidyl acrylate, 2-hydroxypropyl methacrylate, 2-
Examples include, but are not limited to, hydroxypropyl acrylate, polyethylene glycol-modified methacrylate, polyethylene glycol-modified acrylate, polypropylene glycol-modified acrylate, polypropylene glycol-modified methacrylate, and the like. In using these, one kind or a mixture of two or more kinds may be used. The methyl group or ethyl group of R4 is usually derived from methanol, ethanol or the like.

[0014] polyamic acid ester represented by the formula (1) used in the present invention, the proportion of the structural unit R ₃ is introduced into the carboxyl group is x, a part in R _3, R ₄ is introduced into the remaining The ratio of the structural units is y, the ratio of the structural units in which the carboxyl group is substituted with R ₄ is z, and three types of structural units are mixed. 0 <x, y <1 respectively
00, 0 <z <80 and x + y + z = 100 are satisfied, and x, y, and z represent the percentage of each structural unit. When R ₄ is -CH ₃ or _-C 2 _{H 5} is, z is less practical photosensitive group amount less sensitivity is as low as 80 or more.

The polyamic acid ester (1) in the present invention is usually synthesized as follows. First, a compound having an alcohol group for introducing polyfunctional photosensitive groups R ₃ and R ₄ is dissolved in a solvent, and excess acid anhydride or its derivative is reacted with this. After that, the remaining carboxyl group and acid anhydride group can be reacted with diamine to synthesize.

The lactic acid ester represented by the formula (2) in the present invention dissolves a polyamic acid ester. The obtained photosensitive resin composition has excellent coatability, and when applied to a silicon wafer, repelling, pinholes and the like are extremely unlikely to occur, and is excellent in smoothness. Examples of the lactate ester include methyl lactate, ethyl lactate, n-propyl lactate, i-propyl lactate, n-butyl lactate, t-butyl lactate and sec-butyl lactate. You may use these individually or in mixture of 2 or more types. In order to further improve other characteristics,
There is no problem in using it together with other solvents. Other solvents used include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylformamide, N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, dimethylsulfoxide, hexamethylphosphine. Examples include, but are not limited to, amide, N-methyl-2-pyrrolidone, pyridine, dimethyl sulfone, tetramethyl sulfone, dimethyl tetramethylene sulfone, benzene, benzonitrile, dioxane, butyrolactone, xylene, toluene and cyclohexanone. is not.

The amount of lactic acid ester used is 50 to 100 parts by weight of the polyamic acid ester represented by the formula (1).
It is preferably 500 parts by weight, but is not particularly limited. If the amount of lactic acid ester is 50 parts by weight or less, a uniform solution cannot be obtained, or if it is used in combination with another solvent, a uniform solution is obtained, but the coatability is deteriorated, which is not preferable. When the amount is 500 parts by weight or more, a uniform solution can be obtained, but since the amount of the solvent is too much with respect to the resin solid content, the concentration becomes low, the apparent solution viscosity decreases, and the coating properties such as repellency decrease, which is preferable. Absent.

In the present invention, a sensitizer may be added to improve lithographic properties such as sensitivity and resolution. As a sensitizer

[0019]

[Chemical 4]

[0020]

[Chemical 5]

[0021]

[Chemical 6]

[0022]

[Chemical 7]

[0023]

[Chemical 8]

[0024]

[Chemical 9]

[0025]

[Chemical 10]

[0026]

[Chemical 11]

Examples thereof include, but are not limited to: In addition, one kind or a mixture of two or more kinds may be used. The amount of the photosensitizer added is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the polyamic acid ester. If it is 0.1 part by weight or less, the amount of addition is too small and it is difficult to obtain the effect of improving the sensitivity. If it is 10 parts by weight or more, the sensitizer in the system lowers the strength of the cured film, which is not preferable.

Further, as an initiator, N-phenylglycine, N-phenyldiethanolamine, 3,3 ', 4,4'-benzophenonetetracarboxylic acid, tetra-t-butyl peroxide, 5-phenyloxazoline, various oxime compounds , 1-phenyl-5-mercapto-to improve shelf life
(1H-tetrazole), 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, pentaerythritol tetrakis-
(Thioglycolate), thioglycolic acid, ammonium thioglycolate, butyl thioglycolate, octyl thioglycolate, methoxybutyl thioglycolate,
Trimethylolpropane tris- (thioglycolate),
Ethylene glycol dithioglycolate, β-mercaptopropionic acid, octyl β-mercaptopropionate, trimethylolpropane tris- (β-thiopropionate), pentaerythritol tetrakis- (β-thiopropionate), 1,4- Butanediol dithiopropionate, thiosalicylic acid, furfuryl mercaptan, benzyl mercaptan, α-mercaptopropionic acid, p-hydroxythiophenol, p-methylthiophenol, thiophenol and the like may be added.

To the photosensitive resin composition according to the present invention, an adhesion aid, an inhibitor, a leveling agent and other various fillers may be added.

In the method of using the photosensitive resin composition according to the present invention, first, the composition is applied to a suitable support such as a silicon wafer, a ceramic or an aluminum substrate. The coating method is spin coating using a spinner, spray coating using a spray coater, dipping, printing, roll coating, or the like. Next, after prebaking at a low temperature of 60 to 80 ° C. to dry the coating film, a desired pattern shape is irradiated with actinic rays. As the actinic rays, X rays, electron rays, ultraviolet rays, visible rays and the like can be used, but those having a wavelength of 200 to 500 nm are preferable.

Next, a relief pattern is obtained by dissolving and removing the unirradiated portion with a developing solution. As a developer, N-
Methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N
-Use dimethylformamide, etc., methanol, xylene, isopropyl alcohol, water, aqueous alkali solution, etc., alone or in combination. As a developing method, a method such as spraying, paddle, dipping, or ultrasonic wave can be used.

Next, the relief pattern formed by development is rinsed. As the rinse liquid, methanol, xylene, ethanol, isopropyl alcohol, butyl acetate, water or the like is used. Next, heat treatment is performed to form an imide ring, and a final pattern having high heat resistance is obtained.

The photosensitive resin composition according to the present invention is useful not only for semiconductor applications, but also as an interlayer insulating film of a multilayer circuit, a cover coat of a flexible copper clad board, a solder resist film, a liquid crystal alignment film and the like.

[0034]

The present invention will be described in detail with reference to the following examples. Example 1 65.5 g (0.30 mol) of pyromellitic dianhydride
3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride
225.5 g (0.70 mol) and 2-hydroxy-1,3
-Dimethacryloxypropane 456 g (2.00 mol)
After esterifying the carboxyl group with, a polyamic acid ester copolymer was obtained using 170.2 g (0.85 mol) of 4,4'-diaminodiphenyl ether as a condensing agent with dicyclohexylcarbodiimide. The dicyclohexylurea was filtered off and then reprecipitated in ethanol, the solid matter was filtered and dried under reduced pressure. To 100 parts by weight of this polyamic acid ester, 6 parts by weight of N-phenylglycine, 1 part by weight of 1-phenyl-5-mercapto- (1H-tetrazole), 1 part by weight of 2- (p-dimethylaminostyryl) benzothiazole, tetra 10 parts by weight of ethylene glycol dimethacrylate and 0.05 part by weight of methyl ether hydroquinone were dissolved in 200 parts by weight of ethyl lactate to obtain a photosensitive resin composition.

The obtained solution was coated on a 5-inch silicon wafer by a fully automatic coater (DSIPN-636 manufactured by Dainippon Screen Co., Ltd.) so that the coating film obtained had a thickness of 5 μm, and heated at 100 ° C. with a hot plate. And dried for 3 minutes. No pinholes or peeling were observed in the obtained coating film, and an average of 4.
It was found that at 83 μm, σ _n-1 was excellent at 0.008 μm.

Example 2 The amount of 2-hydroxy-1,3-dimethacryloxypropane in Example 1 was reduced to 228 g, and 32 g of methanol (1.00
A photosensitive resin composition was obtained by reacting in the same manner as in Example 1 except that (mol) was added, and evaluated in the same manner as in Example 1. No pinholes or peeling were observed, and the average film thickness was 4.
At 73 μm, σ _n-1 was as excellent as 0.010 μm.

Example 3 240 g of 2-hydroxyethylmethacrylate was added to 2-hydroxy-1,3-dimethacryloxypropane in Example 1.
A photosensitive resin composition was obtained by reacting in the same manner as in Example 1 except that the amount was changed to (2.00 mol), and evaluated in the same manner as in Example 1. No pinholes or peeling were observed, the film thickness was 5.11 μm on average, and σ _n-1 was 0.008 μm, which was excellent.

Example 4 N-phenylglycine, 1-phenyl-5-mercapto- (1H-tetrazole), 2- (P-dimethylaminostyryl) benzothiazole, tetraethylene glycol dimethacrylate and methyl ether in Example 1 A photosensitive resin composition excluding hydroquinone was obtained and evaluated in the same manner as in Example 1. No pinholes or peeling were observed, and the average film thickness was 4.
At 92 μm, σ _n-1 was as excellent as 0.006 μm.

Example 5 To the photosensitive resin composition obtained in Example 1, 3 parts by weight of trimethoxysilylpropyl methacrylate was further added,
The obtained photosensitive resin composition was evaluated in the same manner as in Example 1. No pinholes or peeling were observed, and the average film thickness was 4.
At 84 μm, σ _n-1 was as excellent as 0.010 μm.

Example 6 A photosensitive resin composition was obtained in the same manner as in Example 1 except that ethyl lactate in Example 1 was changed to methyl lactate, and evaluated in the same manner as in Example 1. No pinholes or peeling were observed, the film thickness was 4.62 μm on average and σ _n-1 was 0.006 μm.
And was excellent.

Example 7 A photosensitive resin composition was obtained in the same manner as in Example 1 except that the ethyl lactate in Example 1 was changed to t-butyl lactate, and evaluated in the same manner as in Example 1. No pinholes or peeling were observed, the film thickness was 5.23 μm on average and σ _n-1 was 0.018 μm.
m was excellent.

Example 8 A photosensitive resin composition was obtained in the same manner as in Example 1 except that 100 parts by weight of 200 parts by weight of ethyl lactate in Example 1 was changed to N-methyl-2-pyrrolidone. Evaluation was performed in the same manner as in Example 1. No pinholes or peeling were observed, the film thickness was 4.52 μm on average, and σ _n-1 was 0.010 μm, which was excellent.

Comparative Example 1 A photosensitive resin composition was obtained in the same manner as in Example 1 except that ethyl lactate in Example 1 was changed to N-methyl-2-pyrrolidone, and evaluated in the same manner as in Example 1. However, repelling occurred from the periphery of the wafer toward the center. The thickness of the obtained coating film was 4.48 μm and σ _n-1 was 0.65 μm, which was a large variation.

Comparative Example 2 A photosensitive resin composition was obtained in the same manner as in Example 1 except that the ethyl lactate in Example 1 was changed to ethyl acetate, and the same evaluation was performed. The coating film was not repelled, but pinholes were observed at several places. The film thickness was 4.54 μm, and σ _n-1 was 1.52 μm, which was a large variation.

Comparative Example 3 A photosensitive resin composition was obtained in the same manner as in Example 1 except that the ethyl lactate in Example 1 was changed to lactic acid, and the same evaluation was attempted. Although the coating film was not repelled, numerous pinholes were confirmed. The film thickness was 4.96 μm and σ _n-1 was 0.88 μm, which was a large variation.

[0046]

When the resin composition of the present invention is applied to a silicon wafer or the like, neither repellency nor pinhole phenomenon is observed, and the variation in film thickness within the surface of the silicon wafer can be made extremely small.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01L 21/027

Claims (1)

[Claims] 1. A photosensitive resin composition comprising a polyamic acid ester represented by the formula (1) and a lactic acid ester represented by the formula (2). [Chemical 1] _{CH 3 -CH (OH) -COO-} R 7 (2) wherein _{R 7,: CH 3, C} 2 H 5, C 3 H 7 or C ₄ H ₉