JPH05331443A - Filmy adhesive - Google Patents

Abstract

PURPOSE:To obtain a filmy adhesive, excellent in hot bonding strength, low stress properties, heat resistance and shelf life and useful in the electrical and electronic fields, etc., by drying a composition composed of a silicone-modified polyimide, an aromatic polyamine, etc., and a solvent. CONSTITUTION:The filmy adhesive is obtained by drying a composition composed of (A) a silicone-modified polyimide synthesized from an acid dianhydride such as 3,3', 4,4'-benzophenonetetracarboxylic dianhydride, an aromatic diamine such as a diamine of formula I and a silicone diamine such as diamine of formula II (R1 and R2 are 1-5C bivalent aliphatic or >=6C aromatic group; R3 and R4 are monovalent aliphatic or aromatic group; n is 1-13), (B) a tri- or a polyfunctional polyamine such as melamine or a tri- or a polycarboxylic acid and (C) a solvent such as N-methylpyrrolidone.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film adhesive which has an excellent adhesive force when heated.

[0002]

2. Description of the Related Art Various adhesives are used in the electronics field, and the required performance is becoming severer year by year. Adhesives are generally classified into paste type and film type. The characteristics of film type adhesives are 1)
Easy to handle 2) Accurate control of film thickness is possible,
It is characterized by 3) very little volatile components and 4) little voids. Examples of the material of the film adhesive include a thermosetting resin, a thermoplastic resin, and a combination system thereof. However, in the case of a thermosetting resin, there is a problem in storage stability, while in the case of a thermoplastic resin, it is in a normal state. There is a material having a high adhesive strength, but there is a defect that the adhesive strength is weak especially when heated. Further, adhesives used in the field of microelectronics are desired to have excellent reliability characteristics, and low stress characteristics are particularly important. But,
In the case of a film adhesive, almost no adhesive having excellent low stress property is known. Among them, thermoplastic silicone-modified polyimide is a material having characteristics of low stress, adhesiveness, and heat resistance. However, this material system has a defect that the adhesive strength at the time of heating is very weak, and there is room for improvement.

[0003]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention The inventors of the present invention have conducted a study to improve the heat resistance of a silicone-modified polyimide as a film adhesive, especially the adhesive strength under heat, and as a result, the silicone-modified polyimide has a polyfunctional polyamine or polyfunctional polyamine. It was found that the addition of the functional polycarboxylic acid significantly improved the adhesive strength under heat, and completed the present invention.

[0004]

Means for Solving the Problems That is, the present invention relates to a silicone-modified polyimide synthesized from an acid dianhydride, an aromatic diamine, and a silicone diamine, and a trifunctional or higher aromatic polyamine or a trifunctional or higher polycarboxylic acid. It is a film-like adhesive characterized by drying a composition comprising a solvent.

The silicone-modified polyimide used in the present invention is synthesized from acid dianhydride, aromatic diamine and silicone diamine. Regarding the acid dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid dianhydride 3,3 ′, 4, which gives a polymer having good adhesion,
4'-oxydiphthalic anhydride and the like are preferably used, but not limited thereto. Next, examples of aromatic diamines include 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4′-diaminodiphenyl sulfide, 2,2.
-Bis [4- (4-aminophenoxy) phenyl] propane, 4,4'-diaminobenzanilide, bis [4-
(3-Aminophenoxy) phenyl] sulfone, 2,
4-toluenediamine, bis [4- (4-aminophenoxy) phenyl] ether, 3,4′-diaminodiphenyl ether and the like can be mentioned, but 1,3-bis (3-aminophenoxy) represented by the following formula (1): Benzene is a raw material that is particularly excellent in heat resistance, adhesiveness and solubility of the polymer.

[0006]

[Chemical 3]

Next, as an example of the silicone diamine,
Diamines of the following formula (2) are known.

[0008]

[Chemical 4]

Here, R ₁ and R _{2 are a} divalent aliphatic group having 1 to 5 carbon atoms or an aromatic group having 6 or more carbon atoms, which may be the same as or different from each other. R ₃ and R _{4 are} monovalent aliphatic groups or aromatic groups, which may be the same or different from each other. n = 1 to 13. Here, the chain length unit number n is preferably 1 to 13. This is because when n exceeds 13, the adhesive force sharply decreases. When the carbon number of R ₁ and R ₂ exceeds 6, it becomes difficult to synthesize silicone diamine. The above-mentioned acid dianhydride, a polymer synthesized from a diamine, has an amine or an acid anhydride or a dicarboxylic acid at the end, and therefore, by adding a trifunctional or more aromatic polyamine or a trifunctional or more polycarboxylic acid to the polymer. When an appropriate temperature of 150 ° C. or higher is reached, an amine and a carboxylic acid form an amide bond as shown in the following formula to cause partial crosslinking between polymers. Therefore, compared to linear polymers, polymers are Liquidity decreases. Further, this reaction does not easily occur at room temperature, and therefore, the fluidity is excellent before the bonding, but the fluidity is decreased after the bonding, and thus the adhesive strength at the time of heating is increased. In order to accelerate these crosslinking reactions, a reaction accelerator may be added within a range that does not impair the preservability.

In the case of adding a trifunctional or more aromatic polyamine for effectively expressing these polymer crosslinks, a silicone-modified polyimide is used as a carboxylic acid terminal,
When a trifunctional or higher polycarboxylic acid is added, the silicone-modified polyimide is preferably amine-terminated.
For that purpose, during the polymer synthesis, the acid anhydride / amine equivalent ratio is set to 0.8 to 1.2, and either one is reacted in an excess state. If it exceeds this range, the molecular weight of the polymer is remarkably reduced, and the film becomes very brittle and not practical.

Examples of trifunctional or higher functional aromatic polyamines as cross-linking agents include melamine, 2,4,6-triaminopyridine, 3,3 ', 4,4'-biphenyltetraamine,
3,3 ', 4,4'-tetraaminobenzophenone and the like. Examples of difunctional or higher polybasic acids include ordinary tetracarboxylic acids of acid dianhydrides. The addition amount of these cross-linking agents is preferably such that the ratio of the equivalent amount to the functional group equivalent amount at the polymer terminal is 0.5 to 2.0. If it is less than 0.5, the effect of crosslinking will not be obtained, and if it exceeds 2.0, the heat resistance will be impaired.

The solvent used here is not particularly limited as long as it dissolves the polymer, but N-methylpyrrolidone, γ-butyrolactone, N, N'-dimethylformamide, diglyme, dioxane, tetrahydrofuran, cyclohexanone and mixtures thereof. Is mentioned.

Next, a method for producing a film adhesive can be easily prepared by casting a composition comprising a silicone-modified polyimide, a crosslinking agent and a solvent on a carrier and drying at a temperature of 100 ° C. or lower. At this time, various fillers may be added to the composition in order to exhibit electrical conductivity, thermal conductivity, abrasion resistance and the like.

The present invention will be specifically described below with reference to examples.

【Example】

Example 1 0.6 mol (175.4 g) of 1,3-bis (3-aminophenoxy) benzene was placed in a four-neck separable flask equipped with a thermometer, a stirrer, a raw material inlet, and a dry nitrogen gas inlet tube. ),
Silicone diamine of the following formula (3) 0.4 mol (336.
0 g)

[0016]

[Chemical 5]

After dissolving in 2000 g of N-methylpyrrolidone, 1.1 mol (341.2 g) of 3,3 ', 4,4'-oxydiphthalic anhydride was gradually added to this system under a nitrogen stream, and the mixture was heated to 20 ° C. While maintaining the system, the mixture is stirred for 5 hours to synthesize a polyamic acid. Next, 129.0 g of toluene was added to this system.
Is added, a Dean Starch reflux condenser is attached in place of the gas inlet tube, the mixture is heated in an oil bath, and the temperature in the system is maintained at 170 ° C. by azeotropic distillation of toluene / water to carry out imidization. The reaction was terminated 5 hours after the generation of water stopped. This polyimide varnish was added dropwise to 300 l of pure water while stirring to precipitate the resin, which was then filtered to recover the resin and dried at 80 ° C. for 24 hours. The FT-IR spectrum of this silicone-modified polyimide was measured to be 1650 cm ^-1
Absorption based on the amide bond before imidization appearing in
Absorption based on the imide ring appearing at 80 cm ^-1 showed that it was 100% imidized. Next, with respect to 85.3 g of the obtained polymer, 3,3 ', 4,4' was used as a crosslinking agent.
-0.01 mol (2.14 g) of tetraaminobiphenyl was added and dissolved in 350 g of cyclohexanone. This varnish is cast on a Teflon plate and heated at 150 ° C for 2 hours
It was dried at r to obtain a film having a thickness of 30 μm. This was cut into 2 mm square pieces, placed on a copper frame, and further a 2 mm square silicon chip was placed, and a load of 30 g was applied on a hot plate at 250 ° C. and held for 60 seconds for pressure bonding. At that time, the shear strength under heat, the storage property, and the wire bonding property when using a 3 × 4 mm patterned chip were evaluated. The evaluation results are shown in Table 1.

Example 2 1,3-bis (3-aminophenoxy) benzene 0.7
mol (204.6 g), the silicone diamine of Example 1
4 mol (336 g), 3,3 ', 4,4'-oxydiphthalic anhydride 1.0 mol (310.2 g) were charged, a polymer was synthesized in the same manner as in Example 1 below, and 100% imidized amino-terminated A silicone modified polyimide was synthesized.
With respect to 85.1 g of this polymer, 3,3 ', 4,4'-
Benzophenone tetracarboxylic acid 0.01mol (3.58
g) was added, and a varnish dissolved in 350 g of cyclohexanone was cast on a Teflon plate to produce a film adhesive, and the shear strength at the time of heating was measured in the same manner as in Example 1 to further improve the storage stability and wire bonding property. evaluated.
The evaluation results are shown in Table 1.

Example 3 1,3-bis (3-aminophenoxy) benzene 0.5
mol (146.2 g), 0.5 mol (420 g) of the silicone diamine of Example 1, and 1.1 mol (341.2 g) of 3,3 ', 4,4'-oxydiphthalic anhydride were charged, and Similarly, a dicarboxylic acid-terminated polymer was synthesized, and 90.7 g of this polymer was added to 3,3 ', 4,4.
0.01 mol of 4'-tetraaminobenzophenone (2.4
2 g), 360 g of silver powder, and 350 g of cyclohexanone were dissolved to prepare a varnish, and 100
A film adhesive having a thickness of μm was produced. This 12
5kgf / cut between alumina ceramic and aluminum plate metalized with gold and cut out to a size of mmφ
The pressure was applied at 180 ° C. for 1 hr with a pressure of cm ² . The hot strength was evaluated. The evaluation results are shown in Table 1.

Comparative Example 1 A film-like adhesive produced by synthesizing a polymer and adding no crosslinking agent was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

Comparative Example 2 A film-like adhesive produced by synthesizing a polymer and adding no crosslinking agent in the same manner as in Example 2 was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

Comparative Example 3 A polymer was synthesized in the same manner as in Example 3, a silver-containing film adhesive was produced in the same manner as in Example 3, and its hot strength was evaluated. The evaluation results are shown in Table 1.

[0023]

[Table 1]

[0024]

The film adhesive of the present invention has a low stress property,
Without impairing the characteristics of the silicone-modified polyimide having excellent adhesiveness, the adhesiveness by adding a cross-linking agent, particularly the strength at the time of heating is improved, and it can sufficiently withstand the heat treatment step after bonding, and It is also a material with excellent storability.

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[Procedure amendment]

[Submission date] July 29, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction content]

The silicone-modified polyimide used in the present invention is synthesized from acid dianhydride, aromatic diamine and silicone diamine. Regarding the acid dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid dianhydride 3,3 ′, 4, which gives a polymer having good adhesion,
4'-oxydiphthalic acid dianhydride and the like are preferably used, but not limited thereto. Next, examples of aromatic diamines include 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4′-diaminodiphenyl sulfide, 2,2.
-Bis [4- (4-aminophenoxy) phenyl] propane, 4,4'-diaminobenzanilide, bis [4-
(3-Aminophenoxy) phenyl] sulfone, 2,
4-toluenediamine, bis [4- (4-aminophenoxy) phenyl] ether, 3,4′-diaminodiphenyl ether and the like can be mentioned, but 1,3-bis (3-aminophenoxy) represented by the following formula (1): Benzene is a raw material that is particularly excellent in heat resistance, adhesiveness and solubility of the polymer.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

After dissolving in 2000 g of N-methylpyrrolidone, 1.1 mol (341.2 g) of 3,3 ', 4,4'-oxydiphthalic dianhydride was gradually added to this system under a nitrogen stream, and the mixture was heated to 20 ° C. While maintaining the system, the mixture is stirred for 5 hours to synthesize a polyamic acid. Next, toluene 129.0 was added to this system.
g is added, a Dean Starch reflux condenser is attached in place of the gas inlet tube, heating is performed in an oil bath, and imidization is performed while azeotropically distilling toluene / water while maintaining the temperature in the system at 170 ° C. The reaction was terminated 5 hours after the generation of water stopped. This polyimide varnish was added dropwise to 300 liters of pure water while stirring to precipitate the resin, and the resin was collected by filtration and dried at 80 ° C. for 24 hours. The FT-IR spectrum of this silicone-modified polyimide was measured to be 1650 cm.
Absorption based on amide bond before imidization appearing at ^-1 and 1
100% from absorption based on imide ring appearing at 780 cm ^-1
It was found to be imidized. Next, with respect to 85.3 g of the obtained polymer, 3,3 ′, 4, and
0.01 mol of 4'-tetraaminobiphenyl (2.14
g) was added and dissolved in 350 g of cyclohexanone.
Cast this varnish on a Teflon plate and heat it to 150 ℃.
And dried for 2 hours to obtain a film having a thickness of 30 μm.
This was cut into 2 mm square pieces, placed on a copper frame, and further a 2 mm square silicon chip was placed, and a load of 30 g was applied on a hot plate at 250 ° C. and held for 60 seconds for pressure bonding.
At that time, the shear strength under heat, the storage property, and the wire bonding property when using a 3 × 4 mm patterned chip were evaluated. The evaluation results are shown in Table 1.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

Example 2 1,3-bis (3-aminophenoxy) benzene 0.7
mol (204.6 g), the silicone diamine of Example 1
4 mol (336 g), 3,3 ', 4,4'-oxydiphthalic acid dianhydride 1.0 mol (310.2 g) were charged, a polymer was synthesized in the same manner as in Example 1 below, and 100% imidized amino terminal was introduced. The silicone-modified polyimide of was synthesized. With respect to 85.1 g of this polymer, 3,3 ′, 4,4
'-Benzophenonetetracarboxylic acid 0.01 mol (3.5
8 g) was added and the varnish dissolved in 350 g of cyclohexanone was cast on a Teflon plate to produce a film-like adhesive, and the shear strength at the time of heating was measured in the same manner as in Example 1 to further improve the storage stability and wire bonding property. evaluated.
The evaluation results are shown in Table 1.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0019

[Correction method] Change

[Correction content]

Example 3 1,3-bis (3-aminophenoxy) benzene 0.5
mol (146.2 g), silicone diamine 0.5 mol (420 g) of Example 1, 3,3 ', 4,4'-oxydiphthalic acid dianhydride 1.1 mol (341.2 g) were charged,
Then, a dicarboxylic acid-terminated polymer was synthesized in the same manner as in Example 1, and 90.7 g of this polymer was used to prepare 3,3 ', 4,4.
0.01 mol of 4'-tetraaminobenzophenone (2.4
2 g), 360 g of silver powder, and 350 g of cyclohexanone were dissolved to prepare a varnish, and 100
A film adhesive having a thickness of μm was produced. This 12
5kgf / cut between alumina ceramic and aluminum plate metalized with gold and cut out to a size of mmφ
The pressure was applied at 180 ° C. for 1 hr with a pressure of cm ² . The hot strength was evaluated. The evaluation results are shown in Table 1.

Claims (4)

[Claims] 1. A composition comprising a silicone-modified polyimide synthesized from an acid dianhydride, an aromatic diamine and a silicone diamine, and a trifunctional or higher aromatic polyamine or a trifunctional or higher polycarboxylic acid and a solvent is dried. A film-like adhesive characterized in that 2. The film adhesive according to claim 1, wherein the terminals of the silicone-modified polyimide are all amines, all dicarboxylic acids, or all dicarboxylic anhydrides. 3. The film adhesive according to claim 1, wherein the aromatic diamine has the following formula (1). [Chemical 1] 4. The film adhesive according to claim 1, wherein the silicone diamine has the following formula (2). [Chemical 2] (R ₁ , R ₂ : a divalent aliphatic group having 1 to 5 carbon atoms or an aromatic group having 6 or more carbon atoms, which may be the same or different from each other. R ₃ , R ₄ : It represents a monovalent aliphatic group or aromatic group, and may be the same or different from each other, n = 1 to 13).