JPH05295115A - Polyimide resin having low thermal expansion and production thereof - Google Patents

Abstract

PURPOSE:To produce the subject resin which in a varnish state has already been oriented to some degree by reacting a specific diamine with a specific acid dianhydride and partially imidizing the resulting polymer to a specific degree. CONSTITUTION:A diamine ingredient consisting mainly of one or more of the diamines represented by formulae I, II, and III (wherein X, Y, and Z each is H, CH3, or C2H5) is reacted, with heating, with an acid ingredient consisting mainly of one or more of the acid dianhydrides represented by formulae IV, V, and VI. The polyaddition product is imidized to a degree of imidization of 5-30%, thereby giving the objective resin. The imidization is conducted at 50-120 deg.C for 1-24hr using N-methyl-2-pyrrolidone, for example, as a solvent, usually under anhydrous conditions preferably in an inert gas atmosphere. The resin is reduced in thermal expansion. It can be easily synthesized from inexpensive raw materials, and the thermal expansion of the resin can be controlled by changing the degree of imidization without changing the monomer composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamic acid used in semiconductor devices, multilayer wiring boards, microelectronic devices, etc., which has excellent low thermal expansion and can be easily synthesized with inexpensive raw materials, and further has a raw material composition. The present invention relates to a low thermal expansion polyimide resin capable of controlling the thermal expansion property by changing the imidization ratio without changing the temperature and its manufacturing method.

[0002]

2. Description of the Related Art As semiconductor chips become finer and larger,
Polyimide resin coating is an essential technology for ensuring reliability. However, when the polyimide coating is carried out,
Since the thermal expansion coefficient of polyimide is different from that of the underlying inorganic material such as silicon and aluminum for wiring, and the metal such as copper, the thermal expansion coefficient is different from that of the heat treatment step, and the silicon wafer is warped, There was a problem in that reliability was lowered due to disconnection of the wiring metal. These are due to the large thermal expansion coefficient of the organic polymer regardless of the polyimide alone. Therefore, recently, those aiming at low thermal expansion have been announced. For example, JP-A-60-32827, 60-44338, 60-152786, 60-208358, 60-243120, 60-250031, 61-60725, 60-210629. Publication, 60-210894
No. 60-221426, 61-69833.
Japanese Patent Publication No. 64-33134, Japanese Patent Laid-Open No. 2-1539
No. 34, No. 2-251584, etc. are mentioned. Although these materials are provided with a low thermal expansion property by using a specific raw material, the raw material is extremely expensive and it is necessary to perform an alignment treatment in the curing step. However, in the latter case, a large thermal expansion coefficient has been a problem in a general use method such as electronic engineering in which stretching and orientation of coating and curing on a constant substrate hardly occur.

[0003]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention In Japanese Patent Application No. 3-308951 filed by the present applicant, the reaction temperature in the production of the polyamic acid composition was examined in detail. I found that is gradually progressing. On the other hand, it was found that at 120 ° C. or higher, hydrolysis takes precedence over ring closure and the molecular weight is significantly reduced. Therefore, the inventors have found a method of lowering the viscosity during the reaction by heating and stirring at 50 to 120 ° C. and at the same time causing a partial ring-closing imidization in parallel with the amidation reaction. INDUSTRIAL APPLICABILITY The present invention is to react a specific diamine with a specific acid dianhydride, further control partial imidization to 5 to 30%, and have a pseudo low-expansion polyimide resin in a varnish state and its production. It provides a method.

[0004]

That is, the present invention provides a diamine represented by the following formula (1):

[0005]

[Chemical 3] (X, Y and Z are selected from H, CH ₃ and C ₂ H ₅ and may be the same or different)

An acid dianhydride represented by the following formula (2)

[0007]

[Chemical 4]

A low thermal expansion polyimide resin containing at least one of the above compounds as a main component and having an imidization ratio after polyaddition reaction of 5 to 30% and an imidization reaction of 50 to 120.
This is a method for producing a low thermal expansion polyimide resin which is carried out at a temperature of 1 to 24 hours.

[0009]

The diamine of formula (1) used in the present invention has a structure in which 1 to 3 aromatic rings are linearly connected by a para bond and has an amino group at both terminals of α and ω positions, and X, Y and Z are H and C
It is selected from H ₃ and C ₂ H ₅ and may be the same or different. Further, one kind or a mixture of several kinds may be used. Furthermore, in order to balance with other characteristics such as adhesion,
It is also possible to use a small amount of other diamines together.

Other diamines to be used in combination are 1, 4
-Bis (3-aminopropyl) tetramethyldisiloxane, m-phenylene-diamine, 1-isopropyl-
2,4-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-diphenyl sulfide, 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, 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, 1,
12-diamino-octadecane, 2,17-diamino-
Eicosane, diaminosiloxane, 2,6-diamino-
4-carboxylic benzene, 3,3'-diamino-
Examples thereof include, but are not limited to, 4,4′-dicarboxylic benzidine and the like. In use, one kind or a mixture of two or more kinds may be used.

The acid dianhydride of the formula (2) used in the present invention is pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, and terphenyltetracarboxylic dianhydride, each having 1 to 3 aromatic rings. It has a rigid structure by being directly connected. The acid dianhydride may be one kind or a mixture of two or more kinds. Further, in order to balance other characteristics such as reactivity, other acid dianhydride may be used in a slight amount in combination.

Other acid dianhydrides used in combination include, for example, benzene-1,2,3,4-tetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 2,2 ', 3,3'-benzophenone tetracarboxylic dianhydride, 2,3,3', 4'-benzophenone tetracarboxylic dianhydride, naphthalene-2,
3,6,7-Tetracarboxylic acid dianhydride, naphthalene-
1,2,5,6-tetracarboxylic dianhydride, naphthalene-1,2,4,5-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride,
Naphthalene-1,2,6,7-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic acid 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 dianhydride, 2,7-
Dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 1,
4,5,8-tetrachloronaphthalene-2,3,6,7
-Tetracarboxylic acid 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, berylylene-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 dianhydride , Phenanthrene-1,2,7,8-tetracarboxylic dianhydride, phenanthrene-1,2,
6,7-Tetracarboxylic acid dianhydride, phenanthrene-
1,2,9,10-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, Examples thereof include, but are not limited to, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride and thiophene-2,3,4,5-tetracarboxylic dianhydride. In addition, when using one, two
It may be a mixture of more than one kind.

The solvent of the reaction system in the present invention is an organic polar solvent having a dipole moment whose functional group does not react with tetracarboxylic dianhydride or diamine. Besides being inert to the system and being a solvent for the product, the organic polar solvent must be a solvent for at least one of the reaction components, preferably both. Typical solvents of this type are N,
N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylformamide, N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, dimethylsulfoxide, hexamethylphosphoramide, N-methyl-2-pyrrolidone , Pyridine, dimethyl sulfone, tetramethyl sulfone, dimethyl tetramethylene sulfone, etc., and these solvents may be used alone or as a mixture. Other non-solvents such as benzene, benzonitrile, dioxane, butyrolactone, xylene, toluene, and cyclohexanone that can be used in combination as a solvent are a dispersion medium of the raw material, a reaction regulator, or volatilization of the solvent from the product. Used as a regulator and film smoothing agent.

The reaction is generally preferably carried out under anhydrous conditions. This is because the tetracarboxylic acid dianhydride may be ring-opened by water and may be inactivated to stop the reaction. Therefore, it is necessary to remove both the water content in the raw material and the water content in the solvent. Further, the reaction is preferably carried out in an inert gas atmosphere. This is to prevent oxidation of the diamine. Dry nitrogen gas is generally used as the inert gas.

The heat treatment temperature is preferably 50 to 120 ° C, more preferably 70 to 90 ° C. 50 ° C
In the following, the progress of imidization is very slow, which is not preferable. Further, at 120 ° C. or higher, hydrolysis takes precedence over ring closure, and the molecular weight remarkably decreases, which is not preferable. The imidation ratio after the heat treatment is preferably 5 to 30%. More preferably, 10 to 20% is suitable. If the imidization ratio is 5% or less, the desired low thermal expansion cannot be obtained, which is not preferable.
When the imidization ratio is 30% or more, the solubility in the solvent decreases,
It is not preferable because the storage stability is lowered. Further, as a method of partial imidization, in addition to thermal imidization, acid imidization or a basic catalyst is used, and there is also chemical imidization. However, this method is not preferable because the above-mentioned chemical reagents remain in the varnish and deteriorate various characteristics. Various methods for measuring the imidization ratio are known. Nuclear magnetic resonance spectroscopy (NMR
Method), Fourier transform infrared spectroscopy (FT-IR method), a method of directly quantifying water associated with imide ring closure, and a method of indirectly calculating from a neutralization titration value of carboxylic acid.

The reaction between the diamine and the tetracarboxylic acid dianhydride in the present invention is preferably carried out in an equimolar amount as much as possible, which also increases the degree of polymerization. If either one exceeds 5 mol%, the degree of polymerization is remarkably reduced, and a low molecular weight product having poor film-forming properties is obtained. Usually, it is preferable to use 1 to 3 mol% of an acid component in order to improve the film characteristics. The imidization heat reaction time is preferably 1 to 24 hours. More preferably, 2 to 5 hours are good. When the reaction time is 1 hour or less, it is difficult to control the conditions and it is difficult to obtain reproducibility. If it is 24 hours or more, the productivity is lowered, which is not preferable.

The polyimide resin produced by the method of the present invention contains various silane coupling agents,
Borane coupling agent, titanate coupling agent,
Aluminum-based coupling agents and other chelate-based adhesion / adhesion improving agents, various solvents, and flow agents may be added. In addition to these, usual acid curing agents, amine curing agents, polyamide curing agents and imidazole, 3 A small amount of a curing accelerator such as a primary amine may be added, and a flexibility imparting agent and a viscosity modifier such as rubber, polysulfide, polyester, and low molecular weight epoxy, talc, clay, mica, feldspar powder, quartz powder, oxidation Fillers such as magnesium, carbon black, colorants such as phthalocyanine blue, tetrabromophenylmethane, flame retardants such as tributyl phosphate, antimony trioxide, may be added a small amount of flame retardant aids such as barium metaborate, The addition of these opens up many applications.

[0018]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 108 g (1 mol) of paraphenylenediamine and 3,
294 g (1 mol) of 3 ′, 4,4′-biphenyltetracarboxylic dianhydride was reacted in N-methyl-2-pyrrolidone at 30 ° C. for 2 hours and then heated at 90 ° C. for 2 hours. The imidation ratio in the obtained polyamic acid was ¹ H-N
It was found to be 18% from MR. 500 this varnish
A 5-inch silicon wafer having a thickness of μm was coated with a spinner so as to have a thickness of 10 μm after curing. After the application, it was cured in an oven at 150 ° C. for 30 minutes and 350 ° C. for 30 minutes. When the amount of warpage of the cured wafer with polyimide was measured by using a surface roughness meter, it was as small as 1.5 μm and showed a good value. Further, when the polyimide film using 2% hydrofluoric acid was peeled from this wafer and the linear expansion coefficient was measured by TMA (thermo-mechanical analysis), it was found to be as low as 2.3 PPM.

Examples 2 to 8 According to the formulations and reaction conditions shown in Table 1, a reaction was carried out in the same manner as in Example 1 to obtain a polyamic acid, which was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1. The warp amount of the cured wafer and the linear expansion coefficient obtained from TMA both showed good values.

Comparative Example 1 The reaction was performed in the same manner as in Example 1 except that the amount of paraphenylenediamine in Example 1 was changed to 200 g (1 mol) of 4,4′-diaminodiphenyl ether, and the same evaluation as in Example 1 was performed. The imidation ratio of the obtained polyamic acid was 23.
%Met. However, the amount of warp of the cured wafer is 34 μm
It turned out to be big. Further, it was found that the linear expansion coefficient obtained from TMA was as high as 36 PPM and the practicality was low. The evaluation results are shown in Table 2.

Comparative Examples 2 to 5 Polyamic acids were obtained by reacting in the same manner as in Example 1 according to the formulation and reaction conditions in Table 2 and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2. Both the amount of warp and the coefficient of linear expansion of the cured wafer had problems in terms of practicality.
In Comparative Example 3, the viscosity was too high and the workability was poor. The amicidation rate of polyamic acid was outside the detection limit. In Comparative Example 4, as in Comparative Example 3, the viscosity was high and the workability was poor. In Comparative Example 5, the crystals were broken out during the reaction and became gel-like and could not be evaluated.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

EFFECTS OF THE INVENTION By selecting a specific diamine and a specific dianhydride, and further, in the synthesis of a polyamic acid, a heating partial ring closure imidization is performed, and the imidization rate is controlled to 5 to 30%, so that the varnish state is already obtained. We have found that a rigid structure occurs and a pseudo-orientation occurs. For this reason, it has become possible to easily form a polyimide film having a low thermal expansion coefficient in an industrially general-purpose use method in which orientation and stretching hardly occur such as coating and curing on a substrate such as a silicon wafer. Furthermore, it became possible to control the thermal expansion coefficient of the cured film by changing the imidization ratio depending on the heating reaction conditions. For this reason, polyimide films with different thermal expansion coefficients can be created with the same raw material, which was impossible in the past, and it is possible for the first time to match the thermal expansion coefficients of various underlying inorganic and metallic materials very easily. It became so.

Claims (2)

[Claims] 1. A diamine represented by the following formula (1): (X, Y and Z are selected from H, CH ₃ and C ₂ H ₅ and may be the same or different) The acid dianhydride represented by the following formula (2): A main component of each of which is one or more compounds, and the imidization ratio after the polyaddition reaction is 5 to 30%. 2. The imidization reaction is carried out at 50 to 120 ° C. for 1 to 24
The method for producing a low thermal expansion polyimide resin according to claim 1, which is carried out for a period of time.