JPH04183771A - Polyimide adhesive composition - Google Patents

Abstract

PURPOSE: To obtain a polyimide adhesive composition having a high adhesion strength capable of unnecessitating an adhesive between a copper foil and a polyimde substrate, by incorporating a bismaleimide modified with a polyamic acid and barbituric acid (derivative).

CONSTITUTION: The desired composition capable of strongly adhering to a copper foil comprises a bismaleimide modified with (A) a polyamic acid of a reaction product of preferably a diamine of formula I and a dianhydride of formula II [wherein R', R" are each an aromatic group, a (siloxane- containing) aliphatic group, an alicyclic group] and/or (B) preferably a barbituric acid (derivative) of formula III [wherein R₁, R₂ are each H, CH₃, C₂H₂, C₆H₅, CH(CH₃)₂, etc.].

COPYRIGHT: (C)1992,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to polyimide adhesive compositions, and more particularly to the use of high adhesion polyimide compositions as substrate materials that are directly adhered to copper foil.

These materials are used in flexible printed circuit boards and tape automated bonding.
(TAB). They are also applicable to polyimide thin film packaging technology.

[Background of the invention]

Polyimide's high temperature resistance and low dielectric constant have led to widespread use in the electronics industry, such as flexible printed circuit boards, self-adhesive tapes (TAB), and thin film packaging. However, polyimide has the disadvantage of lower adhesion to copper. Adhesive on top of it, usually to improve bond strength! Applied between jiil foil and polyimide film. Since the heat resistance of the adhesive used is weaker than that of the polyimide substrate, the resulting flexible printed circuit boards and automatic adhesive tapes (TAB) are of poor quality. Glue-free assembly greatly improves overall performance.

The use of modified polyimide to increase the adhesive strength between a polyimide base material and copper foil is described in JP-A-62-278687 and SAMPLE Journal July/August 1
No. 988, disclosed by the prior art. These known references disclosed that the adhesion of polyimide substrates is improved by including siloxane segments in the polyimide backbone polymer. However, the inclusion of siloxane greatly lowers the glass transition temperature of the polyimide and causes phase-separation. Therefore, homogeneous polyimide films cannot be produced.

JP-A-61-48318 and 62-14107
No. 7 discloses the incorporation of bismaleimide into polyimide materials to improve the heat resistance of the final product. However, these prior patents do not effectively increase adhesion between copper foil and polyimide substrates.

SUMMARY OF THE INVENTION Accordingly, the primary object of the present invention is to improve adhesive properties between copper foil and polyimide substrates when fabricating flexible printed circuit boards, self-adhesive tapes (TAB), and thin film packages. The objective is to provide a high adhesion and high temperature resistant polyimide that can eliminate the need for polyimide.

In accordance with the present invention, the high adhesion polyimide composition is the reaction product of a polyamic acid and a bismaleimide modified with barbic acid or a derivative thereof. In the modification of bismaleimide, the molar ratio of barbic acid to bismaleimide is 1/3 to 1/10, and the reaction temperature is 100 to 13
The polyamic acid used in the present invention is a reaction product of dianhydride and diamine according to any known method. Bismaleimide modified with barbituric acid was mixed with polyamic acid at room temperature to produce 10
A new mixture was formed with -15% solids content.

Thus, the solids percentage of modified bismaleimide reached 5-15 weight percent of total solids.

The polyamic acids suitably used in this invention were reaction products of dianhydrides and diamines. The dianhydride is - ship stock: (wherein Rrr is 4 consisting of at least 2 carbon atoms)
a substituted or unsubstituted aromatic group, aliphatic group, alicyclic group, directly or the following radical: alkylene, dioxyalkylene, arylene, -8O□-,
-O-, -CO-.

0 Y -P -, -C-, -NY-Co-X-CO-NY-,
-Co-NY-X-NY-CO-.

Y Y' -Co-0-X-0-CO-, -0-CO-X-XO-
0-1 and -CO-NY-NY-CO- (wherein X is a divalent alkylene radical, dioxyalkylene radical, or arylene radical, and Y and Y' are an alkyl radical, an aryl radical, or an alicyclic radical. radicals), or a heterocyclic group containing at least one atom N, O1 or S, or a different radical. ). Dianhydrides are carbonylated compounds capable of forming internal diimides, having two sets of carbonylate groups, thus whereas carbonylate groups belonging to a single set are separated by up to three carbon atoms. Thus, each group is bonded on one side to a carbon atom of a single tetravalent radical and on the other side to an oxygen atom.

In the present invention, tetrahydrofuran tetracarboxylic dianhydride, cyclopentane tetracarboxyl dianhydride, or bicyclo-[2,2.

2]-octene-(7)-2,3,5,6-titracarpoxy-2,3:5,6-dianhydride may be used. Aromatic dianhydrides are preferred. Examples of suitable aromatic dianhydrides are: pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3',4,4'-diphenyltetracarboxylic dianhydride 1.4,5.8-naphthalenetetracarboxylic dianhydride, 1.2.5.6-naphthalenetetracarboxylic dianhydride, bis(3,3-dicarboxyphenyl)sulfone dianhydride, and Bis(3,4-dicarboxyphenyl)ether dianhydride.

Diamines suitably used in the present invention have the following formula: 82N
-R'-N)15 In the formula, R' is an aromatic group, an aliphatic group,
selected from the group consisting of alicyclic groups and aliphatic groups including siloxanes. ). Examples of typical diamines are: ethylene diamine, propylene diamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, 2-ethylhexylene diamine, nonamethylene diamine, decamethylene diamine,
2゜11-diamino-dodecane, etc.; meta-phenylene diamine, para-phenylene diamine, 2,2'-naphthalene diamine, 4,4'-biphenylene diamine, methylene dianiline-(4,4'-diaminodiphenylmethane), ethylene diamine Aniline-(4,4'-diaminodiphenylethane), propylene dianiline-(4,4'
-diaminodiphenylpropane), bis-(para-
amino-cyclohexyl) N-phenylamine, bis-
(para-amino-cyclohexyl)N-metalamine,
hexafluoroisopropylidene-bis-(4-phenylamine), 4,4'-diamino-diphenylmethane,
4.4'-Diamino-diphenylethane, 4.4'-diamino-diphenylpropane, 4,4'-diamino-diphenylbutane, 2.6-diamitupyridine, bis-
(4-amino-phenyl)diethylsilane, bis-(4
-amino-phenyl)diphenylsilane, bis-(4-
Amino-phenyl)ethylphosphine oxyto, bis-
(4-amino-phenyl)phenylphosphine oxyto, bis-(4-amino-phenyl)-N-phenylamine, bis-(4-amino-phenyl)-N-methylamine, 3,3'-dimethyl-4 , 4'-diamino-biphenyl, 3,3'-dimethoxy-benzidine, 2,4-bis(0-amino-t-butyl)toluene, bis(var-amino-t-butyl-phenyl)ether, para-
Bis-(2-methyl-4-amino-phenyl)benzene, Barra-bis-(1,1-dimethyl-5-amino-pentyl)benzene, m-xylene diamine, P-xylene diamine, oxydianiline-(4 , 4'-diamino-diphenyl ether), ketodianiline, 4,4'-diamino-diphenyl sulfide, 3.3'-diamino-diphenyl sulfide, 4.4'-diamino-diphenyl sulfone, 3.3'-diamino-diphenyl sulfone,
Bis-(para-amino-cyclohexyl)methane, bis-(para-amino-cyclohexyl)ethane, bis-(
para-amino-cyclohexyl)propane, bis-(para-amino-cyclohexyl) sulfide, bis-(para-amino-cyclohexyl) sulfone, bis-(para-amino-cyclohexyl) ether, bis-(para-
Amino-cyclohexyl)diethylsilane, bis-(para-amino-cyclohexyl)diphenylsilane, bis-(para-amino-cyclohexyl)ethylphosphine oxyto, bis-(para-amino-cyclohexyl)phenylphosphine oxyto, 1゜2 -bis-(3-amino-propoxy)ethane, 2,2-dimethylpropylenediamine, 3-methoxy-hexamethylenediamine, 2
．． 5-Dimethylhebutamethohylene diamine, 5-methylnonamethylene diamine, 1,4-diamino-cyclohexane, 1,2-diamino-octadecane, 2,5-diamino-1,3,4-oxadiazole.

The bismaleimide used in the present invention corresponds to the following general formula: (wherein R is selected from the group consisting of aromatic groups, aliphatic groups, cycloaliphatic groups, and aliphatic groups including siloxanes) do. Examples of typical bismaleimides are: N,N'-ethylene-bis-maleimide, N,N'-
Butylene-bis-maleimide, N,N'-phenylene-bis-maleimide, N,N'-hexamethylene-bis-maleimide, N,N'-4,4'-diphenylmethane-bis-maleimide, N,N'-4,4'-diphenyl ether-bis-maleimide, N,N'-4,4'
-diphenylsulfone-bis-maleimide, N, N'
-4,4'-dicyclohexylmethane-bis-maleimide, N,N'-xylylene-bis-maleimide, N,N
'-diphenylcyclohexane-bis-maleimide, etc.

The barbic acid used has the following general formula: (wherein R1 and R2 are respectively -H, -C)13°C2)+2,
C6H5, CH(CH3)2, CHzCH(
CHi)z.

CH2CHZCH(CH:l)z, and -CH(C
H3) selected from the group consisting of CH2Cl1ZCH3.

) corresponds to

[Description of preferred embodiments]

Example 1 (A) Production of modified bismaleimide 8.66 g of N,N'-4,4'-diphenylmethane-
Bis-maleimide was dissolved in 20 g of butyrolactone. After addition of 1 g of barbituric acid, the resulting solution was reduced to 11
The mixture was stirred at 0°C for 1 hour.

(B) Production of polyamic acid 500jlj! In a 4-neck reactor, 17.45 g of 4
．． 4'-Diaminodiphenyl-ether (DDE) was added and dissolved in the mixture of 130d NMP and 30d xylene. 18.55 g under nitrogen atmosphere
(0,085 mol) of pyromellitic dianhydride (PMD
A) was added and reacted for 3 hours while stirring. Addition of a further 0.436 g (0.02 mol) of PMDA and reaction for 2 hours gave a polyamic acid solution with a solids content of 18.5%.

30 g of modified bismaleimide obtained in method (A) were dissolved in 1.88 g of polyamic acid formed in method (B) at room temperature. 8.9 g of NMP was added to the resulting solution to a solids content of 15%. The final product was applied electrophoretically to a degreased Cu plate and baked according to the described conditions as listed below to form a smooth-like film.

a. First, increase the temperature to 100℃ within 30 minutes,
Maintain at 0°C for 1 hour.

b. Second, increase the temperature from 100°C to 200°C within 1 hour.
Increase temperature to 200°C and maintain at 200°C for 1 hour.

C0 Thirdly, increase the temperature from 200°C to 300°C within 1 hour.
Increase temperature to 300°C and maintain at 300°C for 1 hour.

d. Fourth, increase the temperature from 300°C to 350°C for 30 minutes and maintain at 350°C for 30 minutes.

e. Finally, the temperature is cooled down to room temperature within 3 hours.

The Co foil used in this example includes two types. One type is TC
PI (trademark of Nippon Mining Co, Ltd.), others are Taiwan Copper Fo
Manufactured by il Co, Ltd. The adhesion of copper to the polyimide substrate formed in this example was measured using a peel tester and the results are listed in Table I. The physical properties of the final product obtained are similar to those of conventional polyimide substrates.

Example 2 (A) Preparation of modified bismaleimide 11.55 g of N,N'-4,4'-diphenylmethane-bis-maleimide were dissolved in 25 g of T-butyrolactone. After addition of 1 g of barbic acid, the resulting solution was heated at 120° C. for 1 hour while maintaining agitation.

(B) Preparation of polyamic acid Into a 500 d four-necked reactor, 13.8 g of 4,4'-diaminodiphenyl-ether (DDE) was added;
The solution was dissolved in a mixture of 30% NMP and 30% xylene. Under nitrogen atmosphere, 20.93 g (0,065
mol) of benzophenonetetracarboxylic dianhydride (B
TDA) was added and allowed to react for 3 hours while maintaining stirring. Additionally 1.288 g (0,004 mol) of BT
Addition of DA and reaction for 2 hours gave a polyamic acid solution with a solids content of 18.4%.

30 g of modified bismaleimide obtained by method (A),
It was dissolved at room temperature in 1.8 g of polyamic acid formed in method (B). 1g of NAP with a solid content of 15%
was added to the resulting solution so that

The final product was applied to degreased Co foil and betaed under the conditions described in Example 1 to form a smooth-like film. The peel strength of the final product of this example is also listed in Table 3.

Comparative Example 1 0.62 g of N,N'-4,4'-diphenyl-methane-bis-maleimide was dissolved in 10.5 g of NMP. After addition of 30 g of polyamic acid obtained according to method (B) of Example 1, the final product was applied to a degreased Cu foil,
Beta was carried out under the conditions described in Example 1.

The peel strength of the final product is listed in Table ■.

Comparative Example 2 The polyamic acid obtained by method (B) of Example 1 was applied directly to a degreased Cu foil and baked under the conditions described in Example 1. The peel strengths of examples are listed in Table ■.

Comparative Example 3 0.61 g of N,N'-4,4'-diphenyl-methane-bis-maleimide was dissolved in 10.3 g of NMP. After addition of 30 g of polyamic acid obtained according to method (B) of Example 2, the final product was applied to a degreased Cu foil and betaed under the conditions described in Example 1.

The peel strength of the final product is listed in Table I.

Comparative Example 4 The polyamic acid obtained by method (B) of Example 2 was applied directly to a degreased Cu foil and betaed under the conditions described in Example 1. The peel strengths of the examples are listed in Table I.

Table I TCPI 8 B, 26.54.56.74.5Ta
iwan Cu board 6 6.0 3.5 3.0 3.
43.2 Although the present invention has been described in detail, it will be understood by those skilled in the art that various modifications can be made without departing from the spirit of the invention and the scope of the claims.

Accordingly, the invention is not intended to be limited except as by the claims appended hereto.

Claims (1)

[Scope of Claims] 1. A polyimide adhesive composition that strongly adheres to copper foil, comprising: polyamic acid; and bismaleimide modified with one member of the group consisting of barbituric acid and its derivatives. 2. The above polyamic acid is (i) H_2N-R'-NH_2 (ii) ▲ There are numerical formulas, chemical formulas, tables, etc. ▼ (In the formula, R' and R'' are aromatic groups, aliphatic groups, alicyclic groups, 3. The polyimide adhesive composition according to claim 1, wherein the barbituric acid has the following formula: ▲ Numerical formula, chemical formula, There are tables, etc. ▼ (In the formula, R_1 and R_2 are -H, -CH_3, -
C_2H_2, -C_6H_5, -CH(CH_3)_
2, -CH_2CH(CH_3)_2, -CH_2CH
_2CH(CH_3)_2, and -CH(CH_3)
CH_2CH_2CH_3 is selected from the group consisting of CH_2CH_2CH_3. ) The polyimide adhesive composition according to claim 1, which corresponds to the following. 4. Bismaleimide has the following formula: ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R is an aromatic group, an aliphatic group, an alicyclic group, and 2. The polyimide adhesive composition of claim 1, which is selected from the group consisting of aliphatic groups including siloxanes. 5. The polyimide adhesive composition according to claim 1, wherein the molar ratio between the barbituric acid and the bismaleimide is 1/3 to 1/10. 6. The solids percentage of the modified bismaleimide is 5% of the total solids.
The polyimide adhesive composition of claim 1 in the range of -15 weight percent.