JPS63234589A - Multilayer interconnection board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a multilayer wiring board, and more particularly to a multilayer wiring board that is free from curling and has excellent adhesion between a circuit and an insulating material.

[Prior Art] In recent years, there has been an increasing demand for electrical and electronic equipment to be smaller and lighter, and to streamline assembly work, and the wiring materials used therein are also becoming smaller and more dense.
Multilayer wiring materials are one of them.

Conventionally, multilayer wiring boards, such as printed circuit boards, are mainly of rigid type, and glass epoxy, glass polyimide, and the like are used.

However, these multilayer wiring boards are not flexible and
Moreover, as the number of layers increases, the thickness and weight of the substrate increases, which limits the scope of its use.

On the other hand, flexible wiring boards have excellent flexibility and are lightweight, and have greatly contributed to the miniaturization and thinning of electrical and electronic devices, but so far only single-layer or double-layer types are available. It has not been put into practical use, and creating even more layers is a major challenge.

By the way, various methods have been proposed as techniques for multilayering three or more layers in a flexible wiring board. For example, a method is proposed in which a circuit is formed on an insulator and then a B-stage polyimide film and a conductor are stacked (1984, 8). 2
7 Nikkei Electronics), after coating the circuit formed on the insulator with a heat-resistant resin such as polyimide,
A method of forming a circuit by vacuum plating method, electroplating method, etc.
Japanese Unexamined Patent Publication No. 61-212,096) and the like have been proposed.

[Problems to be solved by the invention] However, in any of the above methods, the coefficient of linear expansion of the insulating layer is larger than that of the conductor, resulting in curling, the need for a specific conductor, or the need for a conductor. It has not been put into practical use due to reasons such as insufficient adhesion.

On the other hand, even in integrated circuits, multiple wiring layers are sometimes provided on the circuit, but even in this case, the resin used for the interlayer insulating film has a large coefficient of linear expansion, which can cause disconnections in the aluminum wiring or other problems in the circuit. The child was admitted when the child was born.

Therefore, as a result of intensive research to solve the above-mentioned problems, the present inventor discovered that polyamide-imide resin having a specific structure has low thermal expansion and excellent adhesion to conductors. The invention has been completed.

Therefore, an object of the present invention is to provide a highly reliable multilayer wiring board that does not curl and uses a heat-resistant resin that has low thermal expansion and excellent adhesion to conductors.

[Means for Solving the Problems] That is, the present invention provides a multilayer wiring board having a plurality of insulating layers and a plurality of circuit layers, in which at least one of the insulating layers has any of the following general formulas (I>). a group represented by ), and Ar2 is 4
This is a multilayer wiring board containing a polyamide-imide resin having a structural unit represented by the following formula.

In the present invention, a polyamideimide resin represented by the above general formula (I>) is used as the low thermal expansion resin used for the insulating layer.

This polyamide-imide resin is shown by the following general formula, however,
(in the formula, R8 to R8 and n1 to n8 are the same as above) and an aromatic tetracarboxylic dianhydride are used as main raw materials and are obtained by reacting them.

The lower alkyl group and lower alkoxy group that can be introduced as a substituent into the diamine component preferably have less than 10 carbon atoms, and if they have 10 or more carbon atoms, it is difficult to achieve low thermal expansion.

As the diamine component, preferably 4,4'-diaminobenzanilide, 4,3'-diaminobenzanilide, 3
, 4°-diaminobenzanilide and substituted derivatives thereof. Substituents are methyl group, ethyl group, propyl group,
Preferred are methoxy group, ethoxy group, fluorine, chlorine, bromine and the like.

More preferably, the following general formula (where R9 to
R12 represents a lower alkyl group, a lower alkoxy group, halogen or hydrogen, at least one of which is a methoxy group), and more preferably,
2-methoxy-4,4°-diaminobenzanilide. Two or more such diamine compounds may be used simultaneously.

Aromatic tetracarboxylic dianhydride is (however, in the formula A
r2 is the same as above), pyromellitic dianhydride, 3.3', 4.4°-biphenyltetracarboxylic dianhydride, 3,3°, 4,4- Benzophenone tetracarboxylic dianhydride, 3.3°, 4,4
Mention may be made of °-diphenylsulfone tetracarboxylic dianhydride. Pyromellitic dianhydride is preferred for its low thermal expansion effect, but two or more types of tetracarboxylic dianhydride may be used for the purpose of improving physical properties or improving adhesiveness of the tube.

The polymerization reaction involves N-methyl-2-pyrrolidone (NMP>,
O to 200°C in a solvent such as N,N-dimethylformamide (DMF>, N,N-dimethylacetamide (DMAC), dimethylsulfoxide (DMSO), dimethylsulfolane sulfate, butyrolactone, cresol, halogenated phenol, diglyme, etc.) A polyamide-imide precursor solution is thereby obtained, but the reaction solvent is preferably DMA from the viewpoint of reactivity.
C, and the reaction temperature is preferably 0 to 10°C, since it becomes difficult to obtain the low thermal expansion resin used in the present invention when the imidization reaction progresses during the polymerization reaction.
is within the range of

In the present invention, the polyamide-imide precursor solution, which is the polyamic acid obtained in this way, is usually applied onto a circuit board and then dried and imidized. The imide structural unit is preferably 50 mol% or more, more preferably 60 mol%
It is good to have more than one source. If it is less than 50 mol %, the effect of lowering thermal expansion will be reduced and it may be difficult to obtain a multilayer wiring board with little curl.

As for other structural units, various diamines and tetracarboxylic acid compounds can be used to copolymerize or separately synthesized polyimide or its precursor, polyamideimide, etc. can be blended.

Specific examples include p-phenylenediamine, ■-
Phenyl diamine, 4,4゛-diaminodiphenyl ether, 4,4゛-diaminodiphenylmethane, 3.3
°-dimethyl-4,4゛-diaminodiphenylmethane,
2.2-his(4-(4-7minophenoxy)phenyl)propane, 1,2-bis(anilino)ethane, diaminodiphenylsulfone, diaminodiphenylsulfide, diaminobenzoate, 2,2-bis(anominophenyl)propane , 2.2-bis(aminophenyl)hexafluoropropane, 1.5-diaminonaphthalene,
Diaminotoluene, diaminobencytrifluoride,
1,4-bis(p-aminophenoxy)benzene, 4,
4°-bis(p-7minophenoxy)biphenyl, diaminoanthraquinone, 4.4″-bis(3-aminophenoxyphenyl)diphenylsulfone, 1,3-bis(
Anilino)hexafluoropropane, 1,4-bis(anilino)octafluorobutane, 1,5-bis(anilino)decafluoropentane, 1,7-bis(anilino)
Tetradecafluorohebutane, general formula (however, formula Nakaguchi 4 and R16 are divalent organic groups, R
13 and old 5 are monovalent organic groups, p and q are integers larger than 1) Diaminosiloxane, 2
,2-bis(4-(p-aminophenoxy)phenyl)
Hexafluorozolopane, 2,2-bis(4-(3-aminophenoxy)phenyl)hexafluoropropane,
2,2-bis(4-(2-aminophenoxy)phenyl)hexafluoropropane, 2,2-bis(4-(4-
Aminophenoxy)-3,5-dimethylphenyl)hexafluoropropane, 2,2-di's(4-(4-aminophenoxy)-3,5-ditrifluoromedylphenyl)hexafluoropropane, p- Bis(4-amino-
2-trifluoromethylphenoxy)benzene, 4,4
°-Bis(4-amino-2-trifluoromethylphenoxy)biphenyl, 4,4"-bis(4-amino-3-
trifluoromethylphenoxy)biphenyl, 4,4°
-bis(4-amino-2-trifluoromethylphenoxy)diphenylsulfone, 4°4°-bis(3-amino-5-trifluoromethylphenoxy)diphenylsulfone, 2,2-bis(4-(4-amino) -3-trifluoromethylphenoxy)phenyl)hexafluoropropane, benzidine, 3°3°, 5,5°-tetramethylbenzidine, octafluorobenzidine, 3,3°-methoxybenzidine, Kano tolidine, ...-tolidine, 2.2
', 5,5°, 6.6'-hexafluorotridine, 4
．． There are diamines such as 4''-diaminoterphenyl and 4.4°°°-diaminoquaterphenyl, and diisocyanates obtained by reacting these diamines with phosgene.

Examples of tetracarboxylic acids and their derivatives include the following. Here, it is exemplified as a tetracarboxylic acid, and of course, nistylated products, acid anhydrides, and acid chlorides thereof can also be used.

2, 3.3°, 4°-diphenyl ether tetracarboxylic acid, 2, 3.3′,4″-benzophenone tetracarboxylic acid, 2.

3, 6. 7-naphthalenetetracarboxylic acid, 1,4
, 5.7-naphthalenetetracarboxylic acid, 1,2,5.
6-naphthalenetetracarboxylic acid, 3.3'. 4,4°
-diphenylmethanetetracarboxylic acid, 2,2-bis(
3,4-dicarboxyphenyl)propane, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane, 3,4,9.10-tetracarboxyperylene, 2,2-bis(4-( 3.

4-dicarboxyphenoxy)phenyl)propane, 2
, 2-bis(4-(3,4-dicarboxyphenoxy)
]■)Hexafluoropropane, butanetetracarboxylic acid, cyclopentanetetracarboxylic acid, etc. Also included are trimellitic acid and its derivatives.

Furthermore, it is also possible to introduce a crosslinked structure or ladder structure by modifying with a compound having a reactive functional group.

For example, there are the following methods.

m general formula % formula % (wherein R17 is a 2+X-valent aromatic organic group,
Z is a group selected from NH2 group, C0NI-12 group, and 5O2NI-42 group and is ortho to the amine group, and X is 1 or 2. , a pyrrolone ring, an isoindoquinazolinedione ring, etc. are introduced.

(ii) Modify with an amine, diamine, dicarboxylic acid, tricarboxylic acid, or tetracarboxylic acid derivative having a polymerizable unsaturated bond to form a crosslinked structure upon curing.

As the unsaturated compound, maleic acid, nadic acid, tetrahydrophthalic acid, ethynylaniline, etc. can be used.

(iii) It is modified with an aromatic amine having a phenolic hydroxyl group or a carboxylic acid, and a network structure is formed using a crosslinking agent that can react with the hydroxyl group or carboxyl group.

The coefficient of linear expansion can be adjusted by modifying using each of the above components. That is, a polyamide-imide resin consisting only of the structure of General 15 (I>) is
Although it is possible to form an insulating layer having a linear expansion coefficient of 11 or less on It is possible to approximate the coefficient.

In order to obtain a multilayer wiring board with less curl according to the present invention, it is desirable to apply it on the circuit in the form of a polyamideimide precursor. Even if a normal polyamide-imide solution is applied, an insulating layer with low thermal expansion cannot be obtained. Any coating method can be used.

The solvent drying temperature and imidization temperature can be arbitrarily selected.

The solvent drying temperature is preferably 150°C or lower, more preferably 130°C or lower.

The maximum imidization temperature is usually 200°C or higher, preferably 300°C or higher.

On the other hand, the aforementioned polyamide-imide precursor solution is applied to a glass plate, a polished metal plate, etc. by any method, and after drying some or all of the solvent, it is peeled off to obtain a polyamic acid film, and this film is used on a circuit. It is also possible to form an insulating layer by pressing the film under normal pressure or reduced pressure and further heating to perform an imidization reaction. The solvent drying temperature and imidization temperature at this time can be arbitrarily selected. The solvent drying temperature is preferably 150°C or lower, more preferably 130°C or lower. The maximum heat treatment temperature for imidization is usually 200℃.
The temperature is preferably 300°C or higher.

Furthermore, in order to increase the adhesion force during pressure bonding, various solvents may be present at the interface and pressure bonded.

In the present invention, a circuit layer is roughly formed on the insulating layer formed in this way, and the conductor is copper,
Examples include aluminum, iron, gold and silver, palladium, nickel, chromium, molybdenum, and alloys thereof, with copper being preferred.

Any method can be used to attach the conductor onto the insulating layer. For example, in the case of copper, the following can be explained: ■ Copper is deposited on the insulating layer by vapor deposition, and then the copper layer is deposited by electrolysis. A method in which platinum metal such as palladium is chemically or physically deposited on the insulating layer to a thickness that can be used on a substrate, a copper layer is formed on top of it by electroless plating, and then electrolytically deposited. ■ A method of depositing copper on an insulating layer using a sputtering method, and then depositing the copper layer by electrolysis to a thickness that can be used for a substrate. ■ A method of softening or swelling the insulating layer to a rough surface. There are several methods, such as crimping the reinforcing bars.

Generally speaking, the circuit can be formed by any method, such as forming the conductor on one surface and etching it, or forming the conductor to match the shape of the circuit. Furthermore, it is also possible to form a circuit using conductive paste as a method of processing at low cost.

The multilayer wiring board of the present invention has a plurality of insulating layers and a plurality of circuit layers formed in this way, but it is essential that at least one of the insulating layers contains the above polyamide-imide resin. be. Although other insulating layers are optional, it is particularly preferable that the insulating layer, which is an intermediate layer, be made of this low thermal expansion resin from the viewpoint of preventing curling.

The multilayer wiring board of the present invention can be multilayered in this way. For example, if the multilayer technology of the present invention is applied to a commercially available polyimide film, a flexible type multilayer wiring board can be obtained. Furthermore, if the multilayer technology of the present invention is applied to, for example, a glass epoxy board, an unprecedented thin-layer rigid type multilayer wiring board can be obtained.

Further, there is no problem in performing arbitrary circuit processing such as through holes at each stage, and there is no problem in using it as a multilayer wiring layer on an integrated circuit.

Furthermore, in order to increase the adhesion between the insulating layer/circuit layer or between the insulating layer/insulating layer, mechanical treatment, such as siding, aluminum alcoholade, aluminum chelate, silane coupling agent, or alkali treatment with hydrazine, etc.
A chemical surface treatment or an electrical surface treatment such as a corona discharge treatment or a low-temperature plasma discharge treatment may be performed.

In the present invention, in order to lower the coefficient of linear expansion, increase the modulus of elasticity, control fluidity, or reduce costs, powders such as inorganic, organic, or metal powders, I#ft, etc. Pud strands or the like may be mixed into the insulating layer.

[Function] Since the multilayer wiring board of the present invention uses a low thermal expansion resin with excellent adhesion, the multilayer wiring board is curl-free and highly reliable.

[Example] The present invention will be specifically described below based on a synthesis example of a polyamideimide precursor, an example using the same, and a comparative example.

The method for forming the conductor is to form a copper layer with a repulsion of about 2,000A on the insulating layer by sputtering, and then deposit copper on top of it by electrolysis to form a 15μ thick copper layer. was etched into an arbitrary shape with a ferric chloride solution to form a circuit layer.

The method for measuring adhesion is to measure the copper layer of a sample with a width of 10 mm.
The adhesive was peeled off from the insulating layer at a speed of 50 mm/minute in the 80° direction, and a tensile test was performed to determine the adhesion.

= 20 - The coefficient of linear expansion was measured using a thermomechanical analyzer (TMA) using a sample that had undergone sufficient imidization reaction, and was heated to 250'C and then cooled at a rate of 10'C/min to 240°C. The average coefficient of linear expansion from 'C to 100'C was used.

After forming the insulating layer on the circuit board, the curl is 50mm
It was cut out to a size of 50 mm, and its radius of curvature was determined and used as a guide.

The abbreviations on each side are as follows.

PHDA: Pyromellitic dianhydride BPDA: 3.3°, 4,4°-biphenyltetracarboxylic dianhydride 8TDA: 3.3°, 4,4°-benzophenonetetracarboxylic dianhydride CDI: : 4 , 4'-diaminodiphenyl ether DDH: 4,4°~diaminodiphenylmethane Kano TLD
N: O-Tolidine = 21- To HoBA Ding: BAPA: To12 N -G=C0NH-
NHCOsha NH2DHAc Nidimethylacetamide NHP: N-Methyl Synthesis - Pyrrolidone Synthesis Example 1 Flow 200 d/min of nitrogen into a 300 d fourth flask equipped with a thermometer, calcium chloride tube, stirring rod, and nitrogen inlet. while 0.085 mol DAB8, 0.015
mol DDE and 170 d DHAc were added and stirred. DABA could not be dissolved. When this solution was cooled to below 10'C in a water cooling bath and 0.1 mole of PHDA was gradually added, DABA polymerized while gradually dissolving, forming a viscous polyamic acid (polyamideimide precursor). I got it.

Synthesis Example 2 0.075 mol of HoDABA and 170 d of DHAc were added to a 300 d four-loop flask equipped with a thermometer, calcium chloride tube, stirring rod, and nitrogen inlet while flowing nitrogen at 200 d/min. Stirred.

) 1oDABA could not all be dissolved. While cooling this solution in a water cooling bath to below 10'C,
When mole P)ID8 was gradually added,)IODAB
8 underwent a polymerization reaction while gradually dissolving to obtain a viscous solution.

Additionally 0.025 mol DDE and 0.025 mol B
TDA was further stirred using an IJ mouth to obtain a block type polyamic acid (polyamideimide precursor).

Synthesis Examples 3 to 5 In Synthesis Example 2, IDAB instead of MODAB^
A.

) 1oBATA and BAPA were used to produce polyamic acid.

Synthesis Example 6 0.1 mol of 4,3°-NoDABA and 0.1 mol of P
Polyamic acid was produced by reacting HDA in the same manner as in Synthesis Example 1.

Example 1 A circuit layer was formed on a commercially available polyimide film (Upilex S: registered trademark) with a thickness of 25μ, and the resin solution of Synthesis Example 1 was applied thereon, and dried in a hot air dryer at 90°C for 30 minutes. After drying, heat treatment was performed at 130°C for 10 minutes, 150°C for 10 minutes, 250'C for 3 minutes, and 300'C for 3 minutes to cause an imidization reaction and form an insulating layer with a thickness of 25μ. did. This substrate was flat with almost no curls observed.

Roughly, a 15μ thick copper layer was provided as a conductor on this insulating layer, this copper layer was etched to form a circuit layer, and a flexible multilayer wiring board having two circuit layers and two insulating layers was fabricated in the same manner. Obtained. The resulting flexible multilayer wiring board was examined for its curl radius, adhesion, and coefficient of thermal expansion. The results are shown in Table 1.

Examples 2 to 6 Flexible multilayer wiring boards were obtained in the same manner as in Example 1 using the resin solutions of Synthesis Examples 2 to 6.

= 24- Regarding the obtained flexible multilayer wiring boards of each example,
Its curl curvature radius, adhesion force, and thermal expansion coefficient were investigated.

The results are shown in Table 1.

Example 7 A circuit layer was formed on a commercially available polyimide film (Upilex S) with a thickness of 25 μm, the resin solution of Synthesis Example 2 was applied thereon, and an insulating layer was formed by heat treatment in the same manner as in Example 1. A copper layer was then formed on top of this and etched to form a circuit layer. Furthermore, an insulating layer was provided again using the same resin solution, and a circuit layer was formed thereon. This operation was repeated 10 times to produce a multilayer wiring board.

The multilayer wiring board thus obtained was free from curling and had high flexibility. In addition, when the linear expansion coefficient of this insulating layer was measured, it was 7 x 10-6 (
k-1>.

Comparative Example 1 Similarly to Synthesis Example 1, 0.1 mol of DDE and 0.1 mol of PHDA were reacted to obtain polyamic acid.

Using this resin solution, a flexible multilayer wiring board was obtained in the same manner as in Example 1. The resulting flexible multilayer wiring board was examined for its curl radius, adhesion, and coefficient of thermal expansion. The results are shown in Table 1.

Comparative Example 2 In the same manner as in Synthesis Example 1, 0.1 mol of DDE and 0.1 mol of BTDA were reacted to obtain a polyamic acid.

Using this resin solution, a flexible multilayer wiring board was obtained in the same manner as in Example 1. The resulting flexible multilayer wiring board was examined for its curl radius, adhesion, and coefficient of thermal expansion. The results are shown in Table 1.

Comparative Example 3 In the same manner as in Synthesis Example 1, 0.1 mol of o-TI-DN and 0.1 mol of BPDA were reacted in NMP170d to obtain a polyamic acid.

Using this resin solution, a flexible multilayer wiring board was obtained in the same manner as in Example 1. The resulting flexible multilayer wiring board was examined for its curl radius, adhesion, and coefficient of thermal expansion. The results are shown in Table 1.

Table 1 Example 8 After etching a 0.75 m thick glass polyimide copper clad plate to form a circuit, using the resin solution of Synthesis Example 2,
An insulating layer was provided thereon in the same manner as in Example 1. A copper layer was roughly formed and etched to form a circuit layer.

On top of this, an insulating layer was again applied using the same resin solution, and a circuit layer was again provided on top of the insulating layer. This operation was repeated 10 times to obtain a rigid type multilayer wiring board without warping.

This rigid multilayer wiring board was much thinner and lighter than conventional ones.

[Effects of the Invention] The multilayer wiring board of the present invention has less curling, excellent adhesion between layers, and is highly reliable.

Claims (4)

[Claims] (1) In a multilayer wiring board having multiple insulating layers and multiple circuit layers, at least one of the above insulating layers has the following general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [However, , in the formula, Ar1 is a group represented by any of the following general formulas ▲ Numerical formulas, chemical formulas, tables, etc. n1 to n8 are integers of 0 to 4), and Ar2 is a tetravalent aromatic residue. A multilayer wiring board featuring: (2) Polyamide-imide resin has a structure represented by the following general formula (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) (However, in the formula, R1 and R2 and n1 and n2 are the same as above) The multilayer wiring board according to claim 1, which is a polyamideimide resin having units. (3) Polyamide-imide resin has the following general formula (III) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (III) (However, in the formula, R9 to R12 represent a lower alkyl group, a lower alkoxy group, a halogen, or hydrogen; 2. The multilayer wiring board according to claim 1, which is a polyamide-imide resin having a structural unit represented by (at least one of which is a methoxy group). (4) The multilayer wiring according to claim 1, wherein the polyamide-imide resin is a polyamide-imide resin having a structural unit represented by the following general formula (IV) ▲ Numerical formula, chemical formula, table, etc. ▼ (IV) Board.