JPH0598234A - Thermally contact-bondable filmy adhesive - Google Patents

Abstract

PURPOSE:To prepare the title adhesive excellent in heat resistance, workability in thermal contact bonding, adhesion to metals and ceramics, etc., by using a polyimidesiloxane prepd. by a specified preparation method. CONSTITUTION:An acid component comprising Amol of 4,4'-oxydiphthalic dianhydride, Bmol of an acid-anhydride-terminated silicone compd. of formula I (wherein R1 is a trivalent aliph. or arom. group; R2 and R3 are each a monovalent aliph. or arom.. group; and n is 1-100)(e.g. a compd. of formula II), and Cmol of other acid dianhydrides is reacted with Dmol of a diamine component in such molar ratios that (A+B)/(A+B+C+D) is 0.3-0.55 and (A+B+C)/D is 0.8-1.2 provided that 4,4'-oxydiphthalic dianhydride and/or the silicone compd. is an essential reactant. The resulting polyimidesiloxane having a degree of imidization of at least 80% is used for preparing the title adhesive.

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 excellent heat resistance and can be used by thermocompression bonding.

[0002]

2. Description of the Related Art Heretofore, some heat-resistant thermocompression-bondable film adhesives have been known. For example, Japanese Patent Laid-Open No. 1-2822
No. 83, polyamide-imide or polyamide hot-melt adhesive, JP-A-58-157190, JP-A No. 58-157190, a method of manufacturing a flexible printed circuit board using a polyimide adhesive, JP-A-62-235382 and JP-A-62-235383 describes a thermosetting polyimide film adhesive. However, polyamide-based and polyamide-imide-based resins have a drawback that the water absorption rate becomes large due to the hydrophilicity of the amide group, and there is a limit in using them as adhesives for electronic applications requiring reliability. .. The standard conditions for thermocompression bonding of film adhesives described in other publications are 275 ° C, 50kgf / cm ² and 30 minutes, which require electronic components sensitive to heat and pressure and mass productivity. It could not be said that it is necessarily advantageous as a film adhesive for other applications.

On the other hand, conventionally used epoxy type,
Phenolic and acrylic adhesives can be used at relatively low temperatures,
Although it has an advantage that it can be thermocompression-bonded at a low pressure, it needs to be cured to some extent because it is a thermosetting type. Although a thermoplastic resin is often used as a hot melt adhesive, it has a drawback of poor heat resistance.

[0004]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention The inventors of the present invention have earnestly studied to obtain a film adhesive which has excellent heat resistance and can be thermocompression-bonded at low temperature, low pressure and in a short time, and as a result, a specific structure was found. It has been found that the adhesive formed by film-forming the polyimide siloxane has the above-mentioned object and has completed the present invention. An object of the invention is to provide a film adhesive having both heat resistance and thermocompression bonding workability.

[0005]

The present invention is directed to A moles of 4,4'-oxydiphthalic acid dianhydride and B moles of an acid anhydride-terminated silicone compound represented by the formula (1).

[0006]

[Chemical 1]

And an acid component containing C moles of other acid dianhydride components and an amine component containing D moles of diamine components, 4,4 '.
-At least one of oxydiphthalic dianhydride and acid-terminated silicone compound is an essential component, and (A +
B) / (A + B + C + D) is 0.3 to 0.55, (A + B +
C) / D is reacted in the range of 0.8 to 1.2 and at least 80%
The above is a thermocompression-bondable film adhesive made of imidized polyimide siloxane.

The acid dianhydride used in the present invention is
4,4'-oxydiphthalic acid dianhydride (hereinafter abbreviated as ODPA) and an acid-terminated silicone compound. Examples of acid dianhydrides other than both are pyromellitic 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 dianhydride, naphthalene-1,2,5,6-tetracarboxylic dianhydride, Naphthalene
1,2,4,5-tetracarboxylic 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 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 dianhydride, 3,3 ', 4,4'-
Diphenyltetracarboxylic dianhydride, 2,2 ', 3,3'-diphenyltetracarboxylic dianhydride, 2,3,3', 4'-diphenyltetracarboxylic dianhydride, 3,3 ", 4 , 4 "-p-terphenyl tetracarboxylic dianhydride, 2,2", 3,3 "-p-terphenyl tetracarboxylic dianhydride, 2,3,3", 4 "-p-terphenyl 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 (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, bis (2,3-dicarboxy Phenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4 -Dicarboxyphenyl) eta Dianhydride, perylene-2,3,8,9-tetracarboxylic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, perylene-4,5,10,11-tetracarboxylic Acid dianhydride, perylene-5,6,11,12-tetracarboxylic dianhydride, phenanthrene-1,2,7,8-tetracarboxylic dianhydride, phenanthrene-1,2,6,7-tetra Carboxylic dianhydride, phenanthrene-1,2,9,10-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrazine-2,3,5,6 -Tetracarboxylic acid dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic acid dianhydride, thiophene-2,3,4,5-tetracarboxylic acid dianhydride and the like, but not limited to It is not something that will be done.

The acid anhydride terminated silicone compound used in the present invention is not particularly limited, and examples thereof include a phthalic anhydride terminated silicone compound and a nadic acid anhydride terminated silicone compound represented by the following formula.

[0010]

[Chemical 2]

The diamine component used in the present invention is not particularly limited, but specific examples thereof include 3,3'-dimethyl-4,4'-diaminobiphenyl and 4,6-dimethyl-m. -Phenylenediamine, 2,5-dimethyl-p-phenylenediamine, 2,4-diaminomesitylene, 4,4'-methylenedi-o-toluidine, 4,4'-methylenedi-2,6-xylidine, 4,4 ' -Methylene-2,6-diethylaniline, 2,4-toluenediamine, m-phenylene-diamine, p-phenylene-diamine, 4,4'-diamino-diphenylpropane, 3,3'-diamino-diphenylpropane, 4 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-butyl) Phenyl) 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,
1,3-bis (3-aminophenoxy) benzene and the like can be mentioned.

The reaction between the acid dianhydride and the diamine in the present invention can be carried out by a known method. Either the acid dianhydride component or the diamine component is dissolved or suspended in an organic solvent in advance, and the other component is gradually added in a powder or liquid state or in a state of being dissolved in the organic solvent. Since the reaction is exothermic, the temperature of the reaction system is preferably maintained near room temperature while cooling.

The molar ratio (A + B + C) / D of the acid dianhydride component and the diamine component is preferably in the vicinity of the equivalent, particularly in the range of 0.8 to 1.2. If either one becomes too large,
It is not preferable because the molecular weight does not increase and the heat resistance and mechanical properties deteriorate. After reacting at around room temperature to synthesize polyamic acid, imidization can be carried out by a known method such as heating or using an acetic anhydride / pyridine catalyst. The imidization ratio is preferably at least 80% or more. If the imidization ratio is lower than 80%, imidization progresses when the film is formed later and thermocompression bonding is performed, water is generated, and voids are caused, resulting in a decrease in adhesive strength, which is not preferable.

The value of (A + B) / (A + B + C + D) is
It is necessary to be 0.3 to 0.55, and if it is less than 0.3, the heat melting property will be reduced, and thermocompression bonding conditions of at least 300 ° C. or higher or 50 kgf / cm ² or higher are required, which is preferable in terms of mass productivity. Absent. If it is 0.3 or more, thermocompression bonding can be performed at a temperature of 250 ° C. or less and a pressure of 20 kgf / cm ² or less in a short time within 10 minutes, and good adhesive strength can be achieved.

In the present invention, it is necessary that at least one of ODPA and acid-terminated silicone compound is contained as an essential component. Due to the structural characteristics of ODPA and the acid-terminated silicone compound, at least one of them is contained in the polyimide so as to satisfy the above-mentioned molar ratio, so that it has excellent heat melting property.
It is possible to obtain a film-like adhesive having good adhesive strength and excellent balance with heat resistance.

The organic solvent used in the present invention is not particularly limited, but one solvent or a mixed solvent of two or more solvents may be used as long as it can be uniformly dissolved. 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, γ
-Butyrolactone, diglyme, tetrahydrofuran,
There are methylene chloride, dioxane, cyclohexanone, and the like, and a poor solvent can be used as a volatilization regulator, a film smoothing agent, etc. within a range in which it can be uniformly dissolved.

The method of using the thermocompression-bondable film-like adhesive of the present invention is not particularly limited, but usually a sufficiently imidized varnish is used as a base material having excellent releasability such as Teflon. After being applied, the solvent is volatilized by heat treatment to form a film, which is peeled from the substrate to obtain a single film. This is sandwiched between the adherends and then thermocompression bonded.
Alternatively, it may be applied on the adherend in advance and then subjected to heat treatment to sufficiently volatilize the solvent, and then thermocompression bonding is performed together with one of the adherends.

If desired, various additives can be added to the polyimide siloxane which is the base resin of the adhesive of the present invention. For example, surface smoothing agents when applied to substrates, leveling agents and various surfactants to enhance wettability, silane coupling agents, and various cross-linking agents to enhance heat resistance after thermocompression bonding of adhesives, etc. Is an additive.
These additives can be used in an amount that does not impair the properties of the film adhesive.

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0020]

【Example】

(Example 1) In a four-neck separable flask equipped with a thermometer, a stirrer, a raw material charging port, and a dry nitrogen gas inlet tube, 1,
3-bis (3-aminophenoxy) benzene (APB) 29.23
g (0.1 mol) to 300 g of N-methyl-2-pyrrolidone (NM
P) and dissolved in 4,4'-oxydiphthalic acid dianhydride (O
DPA) 15.51 g (0.05 mol) and acid-terminated silicone compound of the following formula 50.99 g (0.05 mol)

[0021]

[Chemical 3]

After being gradually added as a powder over 30 minutes, stirring was continued for 2 hours. Dry nitrogen gas was kept flowing all the time, and the system was kept at 20 ° C. for the whole reaction during the reaction by cooling with an ice bath before adding more acid anhydride.

Then, 60 g of xylene was added to this system,
Remove the dry nitrogen inlet tube and replace it with a Dean Starch reflux condenser, remove the ice bath and heat in an oil bath to raise the system temperature. Continue heating while removing water generated by imidization from the system by azeotropic distillation with toluene.
The reaction was terminated 5 hours after the imidization proceeded at 0 to 160 ° C. and no more water was generated. This polyimide varnish was added dropwise to 30 liters of methanol with stirring for 1 hour to precipitate the resin, and only solid content was collected by filtration, and then dried in a vacuum dryer under reduced pressure at 80 ° C for 5 hours. Let
FT-IR of the polyimide siloxane thus obtained
The spectrum was measured, was determined and the absorption based on imide before amide bond appearing at 1650 cm ^-1, the imidization ratio from absorption based on imide rings appearing at 1780 cm ^-1, found that it is 100% imidated It was

This polyimide siloxane was dissolved in diethylene glycol dimethyl ether (diglyme),
The concentration was adjusted to 20%. Using an applicator, cast this varnish on a surface-polished Teflon plate, and heat it in a dryer for 5 hours at 120 ° C to evaporate the solvent and peel it off from the Teflon substrate. It was created. From this film, we cut out a size of 3 mm × 3.5 mm square, and made a copper lead frame and 3 mm × 3.5 mm
It is sandwiched between square-sized silicon chips, and a load of 500 g is applied on a hot plate at 200 ° C (approximately 4.76 kgf / c).
m ² ), after thermocompression bonding for 10 seconds, it was cooled to room temperature and the shear strength was measured with a push-pull gauge.The silicon chip broke at a value of 10 kgf or more, and accurate shear strength could not be obtained, It was firmly bonded. Next, when the same adhesive sample was placed on a hot plate at 260 ° C. for 10 seconds and the shear strength was measured, a strength of 0.9 kgf was obtained. The mode of destruction was cohesive failure, and part of the film remained on both the lead frame and the chip. No void was observed in the film.

Example 2 ODP was used as an acid anhydride component.
A 9.31 g (0.03 mol), acid-terminated silicone compound of the following formula 31.68 g (0.03 mol)

[0026]

[Chemical 4]

12.89 g (0.04 mol) of 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride (BTDA) and 14.62 g (0.05 mol) of APB as a diamine component and 6.11 g of 2,4-diaminotoluene. (0.05 mol), 1,3-bis (3-aminopropyl) tetramethyldisiloxane (APDS) 2.4
A polyimidesiloxane was obtained in the same manner as in Example 1 except that 9 g (0.01 mol) was used, and the imidation ratio was measured and found to be 100%. This resin was dissolved in a 1: 1 mixed solvent of diglyme and butyl cellosolve acetate (BCA) to adjust the concentration to 25%.

Using this varnish, a 50 μm thick film of polyimide, Upilex S, manufactured by Ube Industries, Ltd., was subjected to the same heat treatment as in Example 1 to form a coating film having a thickness of 10 μm. A double-sided coated sample cut into a size of 3 mm × 3.5 mm square is sandwiched between a copper lead frame and a silicon chip, and placed on a hot plate at 250 ° C for 500
A load of g was applied for 10 seconds for bonding. When the shear strength was measured at room temperature, the silicon chip broke at 10 kgf or more. Next, when a similar adhesive sample was placed on a hot plate at 260 ° C. for 10 seconds and the shear strength was measured, it was 2.1 kgf. No void was observed on the surface of the adhesive film.

(Examples 3 to 5 and Comparative Examples 1 to 4) Except for the composition of polyimide siloxane and the imidization time, the same procedure as in Example 1 was carried out to obtain the results shown in Table 1.

[0030]

[Table 1]

As in Examples 1 and 2 and Examples 3 to 5 in Table 1, the ODPA and the acid-terminated silicone compound accounted for 0.3 to 0.55 in terms of the number of moles of the entire resin composition, and the acid anhydride and A film formed by using a polyimide having a diamine molar ratio in the range of 0.8 to 1.2 and an imidization ratio of 80% or more is a comparatively low temperature of 250 ° C. or less, and 10 kgf /
With a relatively low pressure of cm ² or less, strong adhesive strength can be obtained under thermocompression bonding conditions for a short time of 10 seconds.
Even at such a high temperature, the adhesive strength was 0.9 kgf or more.

On the other hand, as in Comparative Examples 1 and 3, ODPA,
When the molar ratio of the acid-terminated silicone compound to the total resin composition was less than 0.3, sufficient adhesive strength could not be obtained under the thermocompression bonding conditions of 250 ° C., 5 kgf / cm ² , and 10 seconds. When the imidization ratio is less than 80% as in Comparative Example 2, voids are generated on the film surface after thermocompression bonding, and thus sufficient adhesive strength cannot be obtained. As in Comparative Example 4, when the molar ratio of the acid dianhydride and the diamine as the raw material of the polyimidesiloxane is out of the range of 0.8 to 1.2, the molecular weight of the obtained resin is lowered and the mechanical strength is extremely lowered so that the adhesive film itself. However, sufficient adhesive strength could not be obtained. As described above, good results could not be obtained except under the conditions of the present invention.

[0033]

EFFECTS OF THE INVENTION The thermocompression-bondable film adhesive of the present invention has excellent adhesiveness to metals such as copper and silicon and ceramics, and is sufficient not only at room temperature but also at solder melting temperature such as 260 ° C. It has excellent adhesive strength and excellent heat resistance. Moreover, it is possible to obtain a heat-resistant film-like adhesive which is unprecedented and is advantageous in terms of mass productivity, which enables thermocompression bonding at low temperature, low pressure, and short time.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Suzuki 1-2-2 Uchisaiwaicho, Chiyoda-ku, Tokyo Sumitomo Bakelite Co., Ltd.

Claims (1)

[Claims] 1. An acid component containing A mol of 4,4′-oxydiphthalic acid dianhydride, B mol of an acid anhydride-terminated silicone compound represented by the formula (1), and C mol of another acid dianhydride component, and a diamine. Component D mol and at least one of 4,4′-oxydiphthalic dianhydride or acid-terminated silicone compound as an essential component, and (A + B) / (A + B + C +
A thermocompression-bondable film-like adhesive composed of polyimide siloxane in which D) is reacted in the range of 0.3 to 0.55 and (A + B + C) / D is in the range of 0.8 to 1.2, and at least 80% or more is imidized. [Chemical 1]