JPH0940922A - Adhesive polyimide sheet and multilayered thin-film circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare an adhesive polyimide sheet which is excellent in flowability and heat resistance in bonding and fabrication. SOLUTION: This adhesive sheet is obtd. by forming an adhesive layer mainly comprising a bismaleimide, a polyimide, and a diamine on a polyimide film, subject to the conditions that the wt. ratio of the bismaleimide compounded to the polyimide compounded is 1-4 and that the amt. of the diamine compounded is 1-10wt.% of the total resin content.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyimide adhesive sheet and a thin film multilayer wiring board using the same as an interlayer insulating film.

[0002]

2. Description of the Related Art With the development of a highly information-oriented society, large-scale computers are required to have higher density mounting.

As one of the above high-density mounting methods, thin-film multilayer wiring boards have been actively researched and developed. As one of the methods for manufacturing this thin-film multilayer wiring board, a method of forming an interlayer insulating film of wiring with a polyimide adhesive sheet with an adhesive has been proposed (JP-A-4-206595).

Generally, the thin film wiring layer is provided on a so-called thick film substrate made of ceramics and a conductive paste with a high wiring density in order to improve a signal transmission speed.

In mounting a large-scale computer, many wiring layers and terminal pins need to be connected within one module substrate, and a solder connection layer must be set to form a module. Therefore, the highest heat resistance is required for the uppermost wiring layer that directly connects the arithmetic elements. Therefore, when the polyimide adhesive sheet is applied, the adhesive is also required to have heat resistance.

As an adhesive sheet, Japanese Patent Application Laid-Open No. 1-1478 is used.
95, JP-A-2-138788, JP-A-3-821.
No. 89 and the like describe the composition of the adhesive sheet material, the manufacturing method, and the manufacturing process of the laminated substrate, but none of them have sufficient heat resistance.

Further, if the heat resistance is increased by adjusting the components of the adhesive containing heat-resistant polyimide as a matrix material, the fluidity at the time of adhesive molding is lowered, and various kinds of components required for mounting on a large-scale computer are required. Good wiring step coverage cannot be obtained for all wiring shapes.

[0008]

In order to realize a high-density thin-film multilayer wiring board for a large-scale computer, it is more effective to share different signals in each thin-film wiring layer. The multilayer wiring board is designed with the same wiring rule. For this reason, the wiring shape of each layer in the thin film multilayer wiring board becomes various.

For example, in a connection layer in which thin film wiring is laminated on a thick film substrate, lands for connecting upper and lower wirings having a large area and a narrow space between the wirings are provided in consideration of tolerances in design and manufacturing processes. Is effective. In the signal wiring layer, it is necessary to make the wiring as dense as possible in order to improve the signal transmission speed, and in the power shielding layer, do not form wiring, but only the smallest via holes for upper and lower layer conduction. It is effective to provide. In order to satisfactorily cover such a wide variety of wiring shapes, the sheet adhesive needs to have high fluidity at the time of adhesive molding.

However, the main component of the conventional polyimide adhesive sheet is polyimide, and does not show liquid flow due to melting unlike general adhesives. That is, the wiring step coverage of the adhesive sheet depends on the shape of the wiring as well as the molding conditions such as temperature and pressure at the time of bonding.

Therefore, when the polyimide adhesive sheets are laminated under a constant adhesive molding condition, a layer in which the wiring steps are not filled well is formed. In particular, this problem becomes remarkable when the adhesive molding is performed at a low pressure in consideration of the load on the thick film substrate which is the lower layer substrate. When such a wiring coating failure (hereinafter referred to as a void) occurs, the insulation between wirings deteriorates, cracks occur during the processing of via holes for vertical conduction, and erosion by the plating solution when plating via holes. There is a problem that occurs. That is, when the fluidity of the adhesive is low, voids occur in the adhesive layer, which causes a serious problem in the manufacturing process and the reliability of the product.

Further, if the heat resistance is low, air bubbles or peeling will occur in the adhesive layer due to the soldering process when the arithmetic element is mounted, which causes a problem in the reliability of the substrate.

Since the wiring step coverage of the above-mentioned polyimide adhesive sheet also depends on the molding conditions, it may be possible to change the molding conditions depending on the wiring structure. However, in this case, it is necessary to set the conditions every time the wiring structure changes, and the manufacturing process It gets complicated.

Although it is conceivable to devise the wiring of each layer so that the voids do not occur, the degree of freedom in wiring design is lost.

Therefore, in order to realize a thin film multilayer wiring board using a polyimide adhesive sheet, an adhesive for the polyimide adhesive sheet having sufficient heat resistance and excellent fluidity is required.

Generally, a polymer having a low heat resistance has a large plastic deformation, and it is considered that such a material is used to improve the fluidity. However, polyimide is used as a material because the heat resistance of the adhesive is high. This is because the heat resistance is not sacrificed for improving the fluidity.

Further, as a means for improving the fluidity of the polyimide adhesive sheet, it is possible to increase the low molecular weight component of the adhesive resin, but if the low molecular weight component is simply increased,
As described in Japanese Patent Application Laid-Open No. 2-138788, the film becomes brittle during sheet formation, resulting in extremely low moldability. When the adhesive is composed of polyimide and bismaleimide, the limit of the addition amount of bismaleimide to polyimide is said to be 50% by weight.

An object of the present invention is to provide a polyimide adhesive sheet having excellent fluidity and heat resistance.

Another object of the present invention is to provide a thin film multilayer wiring board using the above polyimide adhesive sheet as an interlayer insulating film.

[0020]

The gist of the present invention to achieve the above object is as follows.

[1] A polyimide adhesive sheet in which an adhesive layer containing bismaleimide, polyimide and diamine as a main component is provided on a polyimide film, wherein the blending amount of the bismaleimide with respect to the polyimide is 1 to 1 by weight.
4 and the amount of diamine added to the total resin content is 1 to 1
A polyimide adhesive sheet, characterized in that it is 0% by weight.

[2] In a thin film multilayer wiring board in which a wiring layer is formed via an interlayer insulating layer, the interlayer insulating layer has an adhesive layer containing bismaleimide, polyimide and diamine as main components on a polyimide film. A thin film multilayer wiring board comprising a provided polyimide adhesive sheet, wherein the amount of the bismaleimide compounded with respect to the polyimide is 1 to 4 by weight, and the amount of diamine added is 1 to 10% by weight based on the total resin content.

The polyimide has the formula [1]

[0024]

Embedded image

(In the formula, R ¹ is phenyl, biphenyl and benzophenone, and R ² is phenyl, biphenyl, phenyl ether, aminophenoxyphenylmethane, aminophenoxyphenylpropane, aminophenoxyphenylhexafluoropropane and hexafluoromethylaminophenoxyphenyl. It is a polyimide having a repeating unit represented by hexafluoropropane.

As the above-mentioned polyimide, for example, pyromellitic dianhydride and diphenylamino ether are heated and dehydration-condensed in an organic solvent such as diaminoacetamide, dimethylacetamide, dimethylformamide and N-methyl-2-pyrrolidone. Obtained by

The tetracarboxylic dianhydride used in combination is, for example, 2,3,3 ', 4'-tetracarboxydiphenyl, 3,3', 4,4'-tetracarboxydiphenyl, 3,3 '. , 4,4'-Tetracarboxydiphenyl ether, 2,3,3 ', 4'-tetracarboxydiphenyl ether, 3,3', 4,4'-tetracarboxydibenzophenone, 2,3,6,7-tetracarboxynaphthalene 1,4,5,7-tetracarboxynaphthalene, 1,
2,5,6-tetracarboxynaphthalene, 3,3 ', 4,
4'-tetracarboxydiphenylmethane, 2,2-bis
(3,4-dicarboxyphenyl) propane, 3,3 ', 4,
4'-tetracarboxydisulfone, 3,4,9,10-tetracarboxyperylene, 2,2-bis [4- (3,4-
Dicarboxyphenoxy) phenyl] propane, 2,2-
Examples include bis [4- (3,4-dicarboxyphenoxy) phenyl] hexafluoropropane and butanetetracarboxylic acid.

The aromatic diamine is, for example,
p-phenylenediamine, m-phenylenediamine, o
-Phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 4,4 '
-Diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ketone, 4,4'-diaminodiphenylpropane and the like.

The bismaleimide has the formula [2]

[0030]

[Chemical 12]

(In the formula, R ³ represents biphenyl, phenyl ether and biphenyl, R ⁴ and R ⁵ represent hydrogen, lower alkyl having 3 or less carbon atoms and lower fluoroalkyl having 3 or less carbon atoms, and they are different from each other. Bismaleimide.

For example, N, N'-ethylenedimaleimide,
N, N'-hexamethylene bismaleimide, N, N'-dodecamethylene bismaleimide, N, N'-p-xylene bismaleimide, N, N'-m-xylene bismaleimide,
N, N'-1,3-bismethylenecyclohexane bismaleimide, N, N'-1,4-bismethylenecyclohexane bismaleimide, N, N'-2,4-tolylenecyclohexane bismaleimide, N, N'- 2,6-Tolylenecyclohexane bismaleimide, N, N'-3,3'-diphenylmethane bismaleimide, N, N'-4,4'-diphenylmethane bismaleimide, 3,3'-diphenylsulfone bismaleimide, 4, 4'-diphenylsulfone bismaleimide, N, N'-4,4'-diphenylsulfide bismaleimide, N, N'-p-benzophenone bismaleimide,
N, N'-diphenylethane bismaleimide, N, N'-diphenyl ether bismaleimide, N, N '-(methyleneditetrahydrophenyl) bismaleimide, N, N'-(3
-Ethyl) -4,4'-diphenylmethane bismaleimide, N, N '-(3,3'-dimethyl) -4,4'-diphenylmethane bismaleimide, N, N'-(3,3'-diethyl)-
4,4'-diphenylmethane bismaleimide, N, N'-tolidine bismaleimide, N, N'-isophorone bismaleimide, N, N'-p, p'-diphenyldimethylsilyl bismaleimide.

N, N'-benzophenone bismaleimide,
N, N'-diphenylpropane bismaleimide, N, N'-
Naphthalene bismaleimide, N, N'-m-phenylene bismaleimide, N, N'-4,4 '-(1,1-diphenylcyclohexane) bismaleimide, N, N'-3,5- (1,
2,4-triazole) bismaleimide, N, N'-pyridine-2,6-diyl bismaleimide, N, N'-5-methoxy-1,3-phenylene bismaleimide, 1,2-bis- (2- Maleimidoethoxy) ethane, 1,3-bis (3-
Maleimide propoxy) propane, N, N'-4,4'-diphenylmethane-bis-dimethylmaleimide, N, N'-
Hexamethylene-bis-dimethylmaleimide, N, N'-
4,4 '-(diphenylether) -bis-dimethylmaleimide, N, N'-4,4'-(diphenylsulfone) -bis-
Dimethyl maleimide.

2,2-bis- [4- (4-maleimidophenoxy) phenyl] propane, 2,2-bis- [3-methyl-4- (4-maleimidophenoxy) phenyl] propane, 2,2-bis -[3-chloro-4- (4-maleimidophenoxy) phenyl] propane, 2,2-bis- [3-
Bromo-4- (4-maleimidophenoxy) phenyl] propane, 2,2-bis- [3-ethyl-4- (4-maleimidophenoxy) phenyl] propane, 2,2-bis-
[3-Propyl-4- (4-maleimidophenoxy) phenyl] propane, 2,2-bis- [3-isopropyl-
4- (4-maleimidophenoxy) phenyl] propane,
2,2-Bis- [3-butyl-4- (4-maleimidophenoxy) phenyl] propane, 2,2-bis- [3-methoxy-4- (4-maleimidophenoxy) phenyl] propane.

2,2-bis- [4- (4-maleimidophenoxy) phenyl] ethane, 2,2-bis- [3-methyl-4- (4-maleimidophenoxy) phenyl] ethane,
2,2-bis- [3-chloro-4- (4-maleimidophenoxy) phenyl] ethane, 2,2-bis- [3-bromo-4- (4-maleimidophenoxy) phenyl] ethane,
2,2-bis- [4- (4-maleimidophenoxy) phenyl] methane, 2,2-bis- [3-methyl-4- (4-
Maleimidophenoxy) phenyl] methane, 2,2-bis- [3-chloro-4- (4-maleimidophenoxy) phenyl] methane, 2,2-bis- [3-bromo-4- (4-
Maleimidophenoxy) phenyl] methane, 2,2-bis- [4- (4-maleimidophenoxy) phenyl] -1,
1,1,3,3,3-hexafluoropropane, 2,2-bis- [3,5-dimethyl-4- (4-maleimidophenoxy) phenyl] -1,1,1,3,3,3- Hexafluoropropane and the like.

The diamine has the formula [3]

[0037]

Embedded image

(In the formula, R ⁶ is an aromatic derivative having 5 or less aromatic rings, an aliphatic derivative having 30 or less carbon atoms, R ⁷ and R ⁸ are hydrogen, a lower alkyl group having 3 or less carbon atoms, a lower fluoroalkyl group. , Which may be different from each other.)
It is a diamine represented by.

For example, 2,2-bis- [4- (aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis- [4- (aminophenoxy)
Phenyl] propane, 2,2-bis- [4- (aminophenoxy) phenyl] -1,1,1, -trifluoropropane, 2,2-bis- [4- (aminophenoxy) phenyl] -1,1 , 1, -Trifluoroethane, 2,2-bis-
[4- (aminophenoxy) phenyl] -1,1,1, -trifluoromethane, 2,2-bis- [4- (aminophenoxy) phenyl] methane, 2,2-bis- [4- (aminophenoxy) Phenyl] ethane, 2,2-bis- [4-
(Aminophenoxy) phenyl] butane, 2,2-bis-
[4- (aminophenoxy) phenyl] pentane, 2,2
-Bis- (aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 2,2-bis- (aminophenyl)
Propane, 2,2-bis- (aminophenyl) -1,1,1
-Trifluoropropane.

2,2-bis- (aminophenyl) -1,1,
1-trifluoroethane, 2,2-bis- (aminophenyl) -1,1,1-trifluoromethane, 2,2-bis-
(Aminophenyl) methane, 2,2-bis- (aminophenyl) ethane, 2,2-bis- (aminophenyl) butane,
2,2-bis- (aminophenyl) pentane, 2,2-bis- (aminotosyl) -1,1,1,3,3,3-hexafluoropropane, 2,2-bis- (aminotosyl) -1, 1, 1
-Trifluoropropane, 2,2-bis- (aminotosyl) propane, 2,2-bis- (aminotosyl) ethane,
2,2-bis- (aminotosyl) -1,1,1-trifluoroethane, 2,2-bis- (aminotosyl) methane, 2,2
-Bis- (aminotosyl) difluoroethane, 2,2-bis- (aminoxylyl) -1,1,1,3,3,3-hexafluoropropane, 2,2-bis- (aminoxylyl) -1,
1,1-trifluoropropane, 2,2-bis- (aminoxylyl) propane.

2,2-bis- (aminoxylyl) ethane,
2,2-bis- (aminoxylyl) -1,1,1-trifluoroethane, 2,2-bis- (aminoxylyl) methane,
2,2-bis- (aminoxylyl) difluoromethane, 2,
2-bis- (aminobenzyl) -1,1,1,3,3,3-hexafluoropropane, 2,2-bis- (aminobenzyl) -1,1,1-trifluoropropane, 2,2- Screw-
(Aminobenzyl) propane, 2,2-bis- (aminobenzyl) ethane, 2,2-bis- (aminobenzyl) -1,1,
1-trifluoroethane, 2,2-bis- (aminobenzyl) methane, 2,2-bis- (aminobenzyl) difluoromethane, 2,2-bis- (aminophenethyl) -1,1,1,
3,3,3-hexafluoropropane, 2,2-bis- (aminophenethyl) -1,1,1-trifluoropropane,
2,2-bis- (aminophenethyl) propane, 2,2-bis- (aminophenethyl) ethane, 2,2-bis- (aminophenethyl) methane, 2,2-bis- (aminophenethyl)
Difluoromethane.

2,2-bis- (aminobiphenyl) -1,
1,1,3,3,3-hexafluoropropane, 2,2-bis- (aminobiphenyl) -1,1,1-trifluoropropane, 2,2-bis- (aminobiphenyl) propane, 2,
2-bis- (aminobiphenyl) ethane, 2,2-bis-
(Aminobiphenyl) -1,1,1-trifluoroethane,
2,2-bis- (aminobiphenyl) methane, 2,2-bis- (aminobiphenyl) difluoromethane, 2,2-bis- (aminonaphthyl) -1,1,1,3,3,3-hexafluoro Propane, 2,2-bis- (aminonaphthyl) -1,
1,1-trifluoropropane, 2,2-bis- (aminonaphthyl) propane.

2,2-bis- (aminonaphthyl) ethane,
2,2-bis- (aminonaphthyl) -1,1,1-trifluoroethane, 2,2-bis- (aminonaphthyl) methane,
2,2-bis- (aminonaphthyl) difluoromethane, 2,
2-bis- (aminoanthryl) -1,1,1,3,3,3-
Hexafluoropropane, 2,2-bis- (aminoanthryl) -1,1,1-trifluoropropane, 2,2-bis- (aminoanthryl) propane, 2,2-bis- (aminoanthryl) Ethane, 2,2-bis- (aminoanthryl)
-1,1,1-trifluoroethane, 2,2-bis- (aminoanthryl) methane, 2,2-bis- (aminoanthryl) difluoromethane, bis- (10-aminodecyl)-
1,1,1,3,3,3-hexafluoropropane, bis-
(10-aminodecyl) -1,1,1-trifluoropropane.

Bis- (10-aminodecyl) 1,1,1-trifluoroethane, bis- (11-aminoundecyl)-
1,1,1,3,3,3-hexafluoropropane, bis-
(11-aminoundecyl) -1,1,1-trifluoropropane, bis- (11-aminoundecyl) 1,1,1-trifluoroethane, bis- (12-aminododecyl)-
1,1,1,3,3,3-hexafluoropropane, bis-
(12-aminododecyl) -1,1,1-trifluoropropane, bis- (12-aminododecyl) 1,1,1-trifluoroethane, bis- (13-aminotridecyl) -1,
1,1,3,3,3-hexafluoropropane, bis- (1
3-aminotridecyl) -1,1,1-trifluoropropane, bis- (13-aminotridecyl) 1,1,1-trifluoroethane, bis- (14-aminotetradecyl)-
1,1,1,3,3,3-hexafluoropropane, bis-
(14-Aminotetradecyl) -1,1,1-trifluoropropane, bis- (14-aminotetradecyl) 1,1,1
-Trifluoroethane.

Bis- (15-aminopentadecyl) -1,
1,1,3,3,3-hexafluoropropane, bis- (1
5-aminopentadecyl) -1,1,1-trifluoropropane, bis- (15-aminopentadecyl) 1,1,1-
Trifluoroethane, bis- (16-aminohexadecyl) -1,1,1,3,3,3-hexafluoropropane, bis- (16-aminohexadecyl) -1,1,1-trifluoropropane, Bis- (16-aminohexadecyl) 1,
1,1-trifluoroethane, bis- (17-aminoheptadecyl) -1,1,1,3,3,3-hexafluoropropane, bis- (17-aminoheptadecyl) -1,1,1- Trifluoropropane, bis- (17-aminoheptadecyl) 1,1,1-trifluoroethane, bis- (18-aminooctadecyl) -1,1,1,3,3,3-hexafluoropropane, bis- (18-aminooctadecyl) -1,1,
1-trifluoropropane, bis- (18-aminooctadecyl) 1,1,1-trifluoroethane, bis- (19
-Aminononadecyl) -1,1,1,3,3,3-hexafluoropropane, bis- (19-aminononadecyl) -1,
1,1-trifluoropropane, bis- (19-aminononadecyl) 1,1,1-trifluoroethane.

Bis- (20-aminoeicosyl) -1,1,
1,3,3,3-hexafluoropropane, bis- (20-
Aminoeicosyl) -1,1,1-trifluoropropane, bis- (20-aminoeicosyl) 1,1,1-trifluoroethane, bis- (21-aminoheneicosyl)-
1,1,1,3,3,3-hexafluoropropane, bis-
(21-Aminoheneicosyl) -1,1,1-trifluoropropane, bis- (21-aminoheneicosyl) 1,
1,1-trifluoroethane, bis- (22-aminodocosadyl) -1,1,1,3,3,3-hexafluoropropane, bis- (22-aminodocosadyl) -1,1,1- Trifluoropropane, bis- (22-aminodocosadyl)
1,1,1-trifluoroethane, bis- (23-aminotricosadyl) -1,1,1,3,3,3-hexafluoropropane, bis- (23-aminotricosadyl) -1, 1, 1
-Trifluoropropane.

Bis- (23-aminotricosadyl) 1,1,
1-trifluoroethane, bis- (24-aminotetracodyl) -1,1,1,3,3,3-hexafluoropropane, bis- (24-aminotetracodyl) -1,1,1-trifluoro Propane, bis- (24-aminotetracodyl) 1,1,1-trifluoroethane, bis- (30-aminotriacontyl) -1,1,1,3,3,3-hexafluoropropane, bis- (30-aminotriacontyl)-
Examples include 1,1,1-trifluoropropane and bis- (30-aminotriacontyl) 1,1,1-trifluoroethane.

In particular, by using the aromatic diamine, the heat resistance is high, and the compound having a fluorine chain in the molecule has an excellent effect that the dielectric constant is low.

The flowability of the adhesive can be improved by adding 1 to 10% by weight of the above diamine.
In particular, the addition of aromatic diamine was effective in improving the brittleness of the adhesive, and as a result, the compounding amount of maleimide could be increased to 4 by weight ratio with respect to the polyimide.

Addition of more than 10% by weight of the diamine is not preferable because the adhesive film becomes brittle and the tensile strength is lowered. If it is less than 1% by weight, the effect cannot be sufficiently exhibited.

According to the present invention, a polyimide adhesive having high fluidity can be obtained by combining the effect of adding the above diamine and the effect of increasing the low molecular weight component, and a polyimide adhesive sheet having the adhesive formed thereon can be obtained. By using it, it is possible to form a coating layer having various shapes on wirings of various shapes without forming voids even under low pressure molding conditions. Therefore, a thin film multilayer wiring board having high reliability can be realized by using it as an interlayer insulating layer.

[0052]

In the present invention, good wiring step coverage can be imparted to wirings of various shapes because heat resistance is impaired by adding a predetermined amount of diamine to the adhesive of polyimide and bismaleimide. This is because the fluidity can be improved without

[0053]

EXAMPLES The present invention will be described in detail with reference to examples.

Example 1 A polyimide was synthesized from pyromellitic dianhydride and 4,4′-diaminodiphenyl ether.

[0055]

Embedded image

A polyimide precursor represented by
Synthesized from 4,4'-benzophenone tetracarboxylic dianhydride and 4,4'-diaminodiphenyl ether

[0057]

Embedded image

The polyimide precursor represented by the formula (1) was mixed in a weight ratio of 1/1 (hereinafter referred to as PI-1) to prepare 1 of N, N-dimethylacetamide and N-methyl-2-pyrrolidone.
A polyimide varnish was prepared by dissolving 15% by weight in a mixed solvent of 1/1 (weight ratio).

To this polyimide varnish, 2,2-bis-
[4- (aminophenoxy) phenyl] -1,1,1,3,
3,3-Hexafluoropropane (Central Glass:
A diamine compound: AF6) was added in an amount of 5% by weight based on the total amount of the resin, and the mixture was stirred for about 1 hour by a Shinto machine.

Further, 2,2-bis- [4- (maleimidophenoxy) phenyl] -1,1, having the same weight as that of polyimide,
1,3,3,3-Hexafluoropropane (manufactured by Central Glass: Bismaleimide compound: MF6) was added, and the mixture was stirred for about 1 hour with a Shinto machine to obtain an adhesive varnish.

200 mm of a polyimide sheet (manufactured by Hitachi Chemical Co., Ltd .: MCF5000I) in which a copper foil having a thickness of 18 μm is attached to a polyimide film having a thickness of 12 μm by a bar coater using a small coater using this adhesive varnish.
It was applied to the corners. 100% of this adhesive varnish coating
C., 1 hour, and then 200.degree. C., 1 hour, and dried to form an adhesive layer having a film thickness of 10 .mu.m.

The content of diamine in this example is 2.5% by weight based on the total resin content of polyimide and bismaleimide. Hereinafter, the amount of diamine is similarly represented by the content (%) with respect to the total resin content.

[Example 2] PI-1 was used as the polyimide, MF6 was used as the bismaleimide, the compounding ratio of MF6 to PI-1 was 1.0 by weight, diamine AF6 was added by 1% by weight, and an adhesive varnish was prepared. It was prepared in the same manner as in Example 1 and an adhesive layer was formed on the copper foil-clad polyimide sheet.

[Example 3] PI-1 was used as the polyimide, MF6 was used as the bismaleimide, the compounding ratio of MF6 to PI-1 was 1.0 by weight, diamine AF6 was added at 5% by weight, and an adhesive varnish was prepared. It was prepared in the same manner as in Example 1 and an adhesive layer was formed on the copper foil-clad polyimide sheet.

Example 4 PI-1 was used as the polyimide and MF6 was used as the bismaleimide. The weight ratio of MF6 to PI-1 was 1.0, and diamine AF6 was 10%.
An adhesive varnish was prepared in the same manner as in Example 1 except that the adhesive layer was formed on the copper foil-clad polyimide sheet.

Comparative Example 1 PI-1 was used as the polyimide, MF6 was used as the bismaleimide, the compounding ratio of MF6 to PI-1 was 1.0, and the diamine AF6 was not added. An adhesive varnish was prepared in the same manner, and an adhesive layer was similarly formed on the copper foil-clad polyimide sheet.

The fluidity of the adhesive layer of the copper foil-clad polyimide sheet having the adhesive layer produced in the above Examples and Comparative Examples was measured by using a glass probe having a diameter of 2.5 mm and a load of 1 mm.
The result of comparison as the displacement rate of the adhesive by the penetration method under 0 g is shown in FIG.

The fluidity (displacement rate) increases with the addition of the diamine AF6. In the case of AF6, the addition amount is 2.
The improvement effect was highest at 5% by weight.

FIG. 1 also shows the starting temperature of displacement in this test. The starting temperature of displacement is diamine AF6.
The lower the flow starting temperature, the longer the time required for the adhesive to harden, which is advantageous in terms of the step coverage of the wiring.

Example 5 Using the polyimide adhesive sheets of Examples 1 to 4 and Comparative Example 1, a sample substrate was manufactured according to the manufacturing process of the thin film multilayer wiring board shown in FIG. However, the step coverage is the most severe under the low-pressure molding condition because it is a pattern having a wide wiring portion such as a land pattern and a wiring portion with a narrow gap between them. Therefore, the sample substrate was simulated.

A glass ceramic (manufactured by Kyocera) is used as the ceramic substrate 1, and the chromium conductor layer 2 (thickness 50 nm) and the copper conductor layer 3 (thickness) are formed by the sputtering method in consideration of the adhesion with the ceramic substrate 1. 5 μm) and a chromium conductor layer 2 ′ (thickness 50 nm) having a three-layer structure were formed [FIG. 2 (a)].

Lands of 250 μm square (gap of space 4 between lands: 50 μm) were formed on the conductor layer by photoetching method (FIG. 2B).

Next, the substrate on which the land was formed was washed with isopropyl alcohol, and then 0.3% by weight of an aminosilane coupling agent (KBE903, manufactured by Shin-Etsu Silicone).
After immersing in isopropyl alcohol solution for 5 minutes, 120 ℃,
It was dried for 1 hour. Next, a polyimide adhesive sheet 6 on which the carrier copper foil and the adhesive 5 are formed is adhered thereon,
280 ℃, 1.5MP in autoclave under vacuum suction
It was adhered and molded by pressing with a for 1 hour.

After forming the first insulating layer of the polyimide adhesive sheet 6 in this manner, the carrier copper foil was etched out with an aqueous solution of copper chloride, washed successively with pure water and isopropyl alcohol, and vacuum dried at 120 ° C. for 1 hour. [Fig. 2
(C)].

Next, aluminum was vacuum-deposited on the surface of the insulating layer formed of the polyimide adhesive sheet 6, a hole pattern was formed by photoetching, and a via hole 7 having a diameter of 30 μm was formed by dry etching using this as a mask. FIG. 2 (d)]. When processing the via hole 7, the chromium thin film at the bottom of the via hole is simultaneously dry-etched.

After processing the via hole, it is washed again with isopropyl alcohol, the copper exposed at the bottom of the via hole is washed with dilute sulfuric acid to remove the copper oxide film on the surface, and then the via stud 8 is formed by chemical copper plating. A sample substrate was obtained [Fig. 2
(E)].

A solder heat resistance test was carried out by immersing the sample substrate in a solder bath at 330 ° C. for 10 minutes, and the presence or absence of bubbles or peeling was observed. Table 1 shows the results of the film forming property, step coverage, hole formability, via plating property, and solder heat resistance test in each of the above steps.

[0078]

[Table 1]

The polyimide adhesive sheets other than Comparative Example 1 were free from voids, cracks around the via holes, peeling due to plating, and the like, and had good solder heat resistance.

[Example 6] PI-1 was used as the polyimide, MF6 was used as the bismaleimide, and the mixing ratio of MF6 to PI-1 was 1.5 by weight, and diamine AF6 was 2.5.
A polyimide adhesive sheet with a weight% added was prepared in the same manner as in Example 1.

[Example 7] PI-1 was used as the polyimide, MF6 was used as the bismaleimide, the mixing ratio of MF6 to PI-1 was 2.3 by weight, and diamine AF6 was 2.5.
A polyimide adhesive sheet with a weight% added was prepared in the same manner as in Example 1.

[Example 8] PI-1 was used as the polyimide, MF6 was used as the bismaleimide, the compounding ratio of MF6 to PI-1 was 4.0 by weight, and diamine AF6 was 2.5.
A polyimide adhesive sheet with a weight% added was prepared in the same manner as in Example 1.

The fluidity and displacement start temperature of the polyimide adhesive sheets of Examples 6 to 8 are shown in FIG.

The fluidity (displacement rate) is determined by the bismaleimide MF.
It is most excellent that the addition amount of 6 is 70% by weight (Example 7). The displacement start temperature increases with the amount of MF6 added, but is lower than that without diamine AF6.

Example 9 Using the polyimide adhesive sheets of Examples 6 to 8, a sample substrate was prepared and evaluated in the same manner as in Example 5 according to the manufacturing process of the thin film multilayer wiring board shown in FIG. Table 2 shows the evaluation results of the sample substrate.

[0086]

[Table 2]

The step coverage, hole workability, via plating property, and solder heat resistance all showed good results.

Further, using a glass substrate, a conductor layer was formed by a sputtering method to form wiring patterns and groove patterns of 15 μm pitch and 20 μm pitch at equal intervals, and a rectangular groove pattern having a width of 70 μm. The step coverage of the adhesive sheet was observed with an optical microscope. It was confirmed that good step coverage can be obtained even for the above wiring pattern.

Example 10 A polyimide having the following formula

[0090]

Embedded image

(Wherein X is an amine residue, a copolymer consisting of phenyl and biphenyl) and PI-2 having a repeating structure, and MF6 as the bismaleimide are used, and the mixing ratio thereof is 1/1 by weight. Diamine AF
A polyimide adhesive sheet containing 2.5% by weight of 6 was prepared in the same manner as in Example 1.

[Embodiment 11] A polyimide having the following formula

[0093]

Embedded image

PI-3 having a repeating structure shown in:
Using bismaleimide MF6, these compounding ratios are 1 by weight.
/ 1, and 2.5% by weight of diamine AF6 was added.

[Example 12] PI-as polyimide
1, and 2,2-bis (4-maleimidophenoxyphenyl) propane (BBMI) as the bismaleimide,
The mixing ratio of these was set to 1/1 by weight, and 2.5% by weight of diamine AF6 was added.

[Example 13] PI-as polyimide
1 and bismaleimide MF6 were used to make their compounding ratio 1/1 by weight, and 2.5% by weight of 2,2-bis (4-aminophenyl) methane (AM-1) was added as a diamine.

[Example 14] PI-as a polyimide
1 and bismaleimide MF6 were used to make the compounding ratio thereof 1/1 by weight, and 2.5% by weight of 2,2-bis (4-aminophenoxyphenyl) propane (AM-2) was added as a diamine.

Fluidity of Examples 10 to 14, and
Table 3 shows the evaluation results of the wiring step coverage and solder heat resistance of the sample substrate.

[0099]

[Table 3]

The fluidity of these polyimide adhesive sheets varies depending on the composition, but both show good results in terms of wiring step coverage and solder heat resistance.

[0101]

EFFECTS OF THE INVENTION The polyimide adhesive sheet obtained by the present invention has excellent fluidity at the time of adhesive molding and can cover the steps of the wiring in the voidless even under relatively low pressure molding conditions.

As a result, it is possible to provide a thin film multi-layer wiring board having a high wiring design margin and preventing damage due to cracks or the like in via holes in the manufacturing process, and having high insulation between wirings and high reliability.

Further, it is possible to provide a thin-film multilayer wiring board having a heat resistance sufficient to withstand soldering during assembly of elements.

[Brief description of drawings]

FIG. 1 is a graph showing a displacement rate and a displacement start temperature of polyimide adhesive sheets of Examples 1 to 4 of the present invention.

FIG. 2 is a schematic cross-sectional view of a manufacturing process of a thin film multilayer wiring board according to an example of the present invention.

FIG. 3 is a graph showing the displacement rate and the displacement start temperature of the polyimide adhesive sheets of Examples 6 to 8 of the present invention.

[Explanation of symbols]

1 ... Ceramics substrate, 2 ... Chrome conductor layer, 3 ... Copper conductor layer, 4 ... Land space, 5 ... Adhesive agent, 6 ... Polyimide adhesive sheet, 7 ... Via hole, 8 ... Via stud.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H05K 1/03 610 7511-4E H05K 1/03 610N 3/46 6921-4E 3/46 E 6921- 4ET (72) Inventor Yutaka Ito 7-1-1 Omika-cho, Hitachi City, Ibaraki Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Akio Takahashi 7-1-1 Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Hitachi Research Laboratory

Claims (10)

[Claims] 1. A polyimide adhesive sheet in which an adhesive layer containing bismaleimide, polyimide and diamine as a main component is provided on a polyimide film, and the compounding amount of bismaleimide with respect to polyimide is 1 to 4 by weight. A polyimide adhesive sheet, characterized in that the amount of diamine added to the total resin content is 1 to 10% by weight. 2. The polyimide has the formula [1] (In the formula, R ¹ is phenyl, biphenyl, benzophenone, R ² is phenyl, biphenyl, phenyl ether,
Aminophenoxyphenylmethane, aminophenoxyphenylpropane, aminophenoxyphenylhexafluoropropane, and hexafluoromethylaminophenoxyphenylhexafluoropropane are shown. The polyimide adhesive sheet according to claim 1, which is a polyimide having a repeating unit represented by the formula (1). 3. The bismaleimide is represented by the formula [2]: (In the formula, R ³ represents biphenyl, phenyl ether, biphenyl, R ⁴ and R ⁵ represent hydrogen, lower alkyl having 3 or less carbon atoms, lower fluoroalkyl having 3 or less carbon atoms, and these may be different from each other. The polyimide adhesive sheet according to claim 1, which is a bismaleimide represented by the formula (1). 4. The diamine has the formula [3]: (In the formula, R ⁶ is an aromatic derivative having 5 or less aromatic rings, an aliphatic derivative having 30 or less carbon atoms, R ⁷ and R ⁸ are hydrogen, a lower alkyl group having 3 or less carbon atoms, and a lower fluoroalkyl group,
These may be different from each other. The polyimide adhesive sheet according to claim 1, which is a diamine represented by the formula (1). 5. The adhesive has the formula [4]: A polyimide having a repeating unit represented by the formula [5] And a polyimide having a repeating unit represented by the formula: The polyimide adhesive sheet according to claim 1, which contains 4-aminophenoxyphenyl) hexafluoropropane in an amount of 1 to 10% by weight based on the total resin content of the adhesive. 6. A thin-film multilayer wiring board in which a wiring layer is formed via an interlayer insulating layer, wherein the interlayer insulating layer has an adhesive layer containing bismaleimide, polyimide and diamine as main components on a polyimide film. A thin film multilayer wiring board comprising a polyimide adhesive sheet, wherein the amount of the bismaleimide compounded with respect to the polyimide is 1 to 4 and the amount of the diamine added to the total resin is 1 to 10% by weight. . 7. The polyimide has the formula [1]: (In the formula, R ¹ is phenyl, biphenyl, benzophenone, R ² is phenyl, biphenyl, phenyl ether,
Aminophenoxyphenylmethane, aminophenoxyphenylpropane, aminophenoxyphenylhexafluoropropane, and hexafluoromethylaminophenoxyphenylhexafluoropropane are shown. 7. The thin film multilayer wiring board according to claim 6, which is a polyimide having a repeating unit represented by the formula (1). 8. The bismaleimide is represented by the formula [2]: (In the formula, R ³ represents biphenyl, phenyl ether, biphenyl, R ⁴ and R ⁵ represent hydrogen, lower alkyl having 3 or less carbon atoms, lower fluoroalkyl having 3 or less carbon atoms, and these may be different from each other. 7.) The thin-film multilayer wiring board according to claim 6, which is bismaleimide. 9. The diamine has the formula [3]: (In the formula, R ⁶ is an aromatic derivative having 5 or less aromatic rings, an aliphatic derivative having 30 or less carbon atoms, R ⁷ and R ⁸ are hydrogen, a lower alkyl group having 3 or less carbon atoms, and a lower fluoroalkyl group,
These may be different from each other. The thin film multilayer wiring board according to claim 6, which is a diamine represented by the formula (4). 10. The adhesive has the formula [4]: A polyimide having a repeating unit represented by the formula [5] And a polyimide having a repeating unit represented by 2,2-bis (4-maleimidophenoxyphenyl) hexafluoropropane in a weight ratio of 1 to 4 with respect to the polyimide, and 2,2-bis ( 7. The thin film multilayer wiring board according to claim 6, wherein 4-aminophenoxyphenyl) hexafluoropropane is contained in an amount of 1 to 10% by weight based on the total resin content of the adhesive.