JP2000277925A - Insulating resin adhesive for multilayer printed interconnection board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a fire resistance, etc., of an inter-layer insulating adhesive for multilayer interconnection board by comprising a sulfur containing amorphous thermo-plastic resin, weight-average molecular weight in specified range of sulfur containing epoxy resin, multifunctional epoxy resin of epoxy equivalent to a specific value or less, epoxy settling agent, and phosphorus containing compound agent. SOLUTION: An interlayer insulating adhesive for multilayer interconnection board comprises, as essential component, a phosphorus containing amorphous thermo-plastic resin containing polysulfone and polyethersulfone of weight- average molecular weight 103-105, phosphorus containing epoxy resin such as bisphenol type epoxy resin, novolak type epoxy resin, biphenyl type epoxy resin, dicyclopentadiene epoxy resin of weight-average molecular weight 103-105, as well as multifunctional epoxy resin of epoxy equivalent 500 or less, epoxy curing agent, and phosphorus containing compound agent which does not contain halogen. Thus, fire-resistance and heat characteristics are improve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interlayer insulating resin adhesive, and more particularly to an adhesive having excellent thermal characteristics, a constant thickness of an interlayer insulating layer, excellent flame retardancy and storage stability, and 100 ° C.
The present invention relates to an epoxy resin-based interlayer insulating adhesive which can be quickly cured at the above-mentioned high temperature.

[0002]

2. Description of the Related Art Conventionally, when a multilayer printed wiring board is manufactured, one or more prepreg sheets obtained by impregnating a glass cloth base material with an epoxy resin and semi-curing are laminated on an inner circuit board on which a circuit is formed. A process of laminating a copper foil thereon and integrally press-molding with a hot plate press is performed. In such a method, the cost is high due to the step of setting the glass cloth prepreg and the copper foil in the multilayer lamination and the cost of the glass cloth prepreg. Also, at the time of molding, the resin is flowed by heating and pressing to embed the inner layer circuit,
Further, since voids are expelled by the flow of the resin, it is difficult to keep the thickness of the insulating resin between circuit layers constant. in addition,
When a glass cloth is present between circuit layers, if the glass cloth is not sufficiently impregnated with the resin, the moisture absorption resistance and the migration resistance may be affected.

In recent years, in order to solve these problems, a technique of manufacturing a multilayer printed wiring board using existing press equipment without using a glass cloth as an insulating layer between circuit layers has been renewed. However, in the press method, when there is no base material such as glass cloth in the insulating layer, it has been difficult to reduce the thickness variation between circuit layers.

[0004]

In a multilayer printed wiring board using a build-up method, when a film-like interlayer insulating resin layer is used, there is no glass cloth base material, so that the thickness of the interlayer after press-molding varies greatly. Because it is easy, molding conditions must be strictly controlled, and molding is very difficult.

[0005] In such a process, when a coating resin on the roughened surface of the copper foil is formed in one layer and a resin having a high softening point is coated, the flow during molding is small and the flow amount for embedding irregularities of the inner layer circuit is small. It cannot be secured. If the resin layer is formed as a single layer by lowering the softening point of the resin and increasing the flow during molding, the unevenness of the inner layer circuit can be buried, but the flow amount is too large, and it is necessary to secure a constant insulating interlayer thickness. It becomes difficult. For that purpose, Japanese Patent Application 9-20
In the specification of US Pat. No. 3488, this problem has been solved by adopting a two-layer structure of a high flow layer and a low flow layer. However, this method involves many steps in manufacturing and has insufficient thermal characteristics, and cannot be used for CSP, MCM, flip-chip mounting, and the like. We are designing resin to control flow by increasing viscosity. Therefore, a minute difference in the degree of curing of the insulating resin before molding greatly affects moldability, and lacks storage stability at room temperature. In addition to the thermal characteristics, there is a growing demand for an insulating resin having excellent flame retardancy without using a halogen compound. .

[0006] The present invention has been studied to improve such problems, and has been completed. A multilayer printed wiring board having an insulating layer without glass cloth has excellent flame retardancy and thermal characteristics, and is stable in storage. It is an object of the present invention to provide a multilayer printed wiring board which is excellent in performance and has a small variation in the thickness of an interlayer insulating resin which is a problem.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an interlayer insulating adhesive for a multilayer printed wiring board, comprising the following components as essential components. (A) an amorphous thermoplastic resin containing a sulfur component having a weight average molecular weight of 10 ³ to 10 ⁵ , (b) an epoxy resin or a phenoxy resin containing a sulfur component having a weight average molecular weight of 10 ³ to 10 ⁵ , (c)
Polyfunctional epoxy resin having an epoxy equivalent of 500 or less (d) Epoxy curing agent, and (e) a halogen-free phosphorus-containing compound agent.

In the present invention, the (a) component-containing amorphous thermoplastic resin having a weight average molecular weight of 10 ³ to 10 ⁵ reduces the resin flow during press molding and maintains the thickness of the insulating layer. In addition to imparting flexibility to the composition and the composition, it is blended for the purpose of increasing the heat resistance of the insulating resin and reducing the heat history. The component (a) includes polysulfone and polyethersulfone, and the terminal of the sulfur-containing amorphous thermoplastic resin has a hydroxyl group, a carboxyl group,
Alternatively, if modified with an amino group, the reactivity with the epoxy resin is good, so that the phase separation between the sulfur-containing thermoplastic resin and the epoxy resin after thermal curing is suppressed, and the heat resistance of the cured product is improved. For this reason, the above-mentioned modified amorphous thermoplastic resin containing a sulfur component is desirable. The proportion of the high-molecular-weight sulfur-containing amorphous thermoplastic resin is preferably 20 to 70% by weight based on the whole resin. 20
If the amount is less than 10% by weight, the viscosity does not increase and the thickness cannot be maintained sufficiently. Therefore, it is not possible to secure the thickness of the insulating interlayer after pressing, and the smoothness of the outer layer circuit becomes poor, and the heat resistance becomes poor. Easy enough. On the other hand, if the content is more than 70% by weight, the adhesive composition is hard and lacks elasticity, so that it has poor followability and adhesion to the unevenness of the substrate during press molding, which may cause molding voids.

[0009] With only the component (a), the usual pressing conditions (2
(00 ° C. or lower), a fluidity that can be molded is not expected. For the purpose of adjusting the flow, an epoxy resin or a phenoxy resin containing a sulfur component having a weight average molecular weight of 10 ³ to 10 ⁵ (b) is blended. The component (b) is usually a bisphenol S type epoxy resin or a phenoxy resin, or a copolymer epoxy resin or a phenoxy resin of a bisphenol S type and a bisphenol type or a biphenyl type, and has a softening point of 70 to 140 ° C. preferable. In addition to the purpose of the flow adjustment, by having a sulfur component, the compatibility with the component (a) is improved, and the stability as a varnish, the uniformity of the cured product, and the thermal characteristics are maintained. Can be. The mixing ratio is 1 to the entire resin.
0 to 40% by weight. If the amount is less than 10% by weight, the flow during press molding is not sufficient, which tends to cause a decrease in adhesion and molding voids, while if it is more than 40% by weight, heat resistance tends to be insufficient.

[0010] The resin containing the high molecular weight sulfur component of the above components (a) and (b) alone lacks adhesiveness, has insufficient heat resistance at the time of solder mounting, and dissolves in a solvent to coat a copper foil. When varnished, the viscosity is high,
Poor coatability and workability during coating. In order to improve such a defect, an epoxy equivalent of 500 (c) is used.
The following polyfunctional epoxy resin is blended. This mixing ratio is 10 to 70% by weight of the whole resin. If the amount is less than 10% by weight, the above effects cannot be expected sufficiently, and if it exceeds 70% by weight, the effect of the high molecular weight sulfur component-containing thermoplastic resin becomes small. (C) As the epoxy resin of the component, bisphenol type epoxy resin, novolak type epoxy resin,
There are biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, alcohol type epoxy resin, alicyclic epoxy resin, aminophenol type epoxy resin, etc.
In order to impart flame retardancy, a brominated epoxy resin can be used, but in addition to this, a novolak type epoxy resin, a compound containing a hetero atom such as sulfur, nitrogen, etc. Can be made flame-retardant.

Next, the epoxy resin curing agent is not particularly limited, such as an amine compound, an imidazole compound, and an acid anhydride. However, the imidazole compound can sufficiently cure the epoxy resin even if the compounding amount is small. When using an epoxy resin that has become flame-retardant due to bromination, etc.
It is preferable because it can effectively exhibit flame retardancy.
It is particularly preferable that the imidazole compound is solid at room temperature having a melting point of 130 ° C. or higher, has low solubility in the epoxy resin, and rapidly reacts with the epoxy resin at a high temperature of 150 ° C. or higher. Specifically, 2-methylimidazole,
2-phenylimidazole, 2-phenyl-4-methylimidazole, bis (2-ethyl-4-methyl-imidazole), 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxy Examples include methyl imidazole and triazine addition type imidazole. These imidazoles are uniformly dispersed as fine powder in the epoxy resin varnish. Since the compatibility with the epoxy resin is small, the reaction does not proceed at room temperature to 100 ° C., so that the storage stability can be kept good. Then, when heated to 150 ° C. or more at the time of heat and pressure molding, it reacts with the epoxy resin to obtain a uniform cured product.

Other curing agents include phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride,
Acid anhydrides such as methylbutenyl anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic anhydride; Examples thereof include an amine complex of boron halide, dicyandiamide or a derivative thereof, and those obtained by epoxy adducting or microencapsulating these can also be used. In addition to the epoxy resin and the curing agent, a component that reacts with the epoxy resin or the curing agent can be blended. For example, epoxy reactive diluents (such as phenylglycidyl ether as a monofunctional type, resorcin diglycidyl ether and ethylene glycol glycidyl ether as a bifunctional type, and glycerol triglycidyl ether as a trifunctional type), resol type or novolac type phenol type Resins, isocyanate compounds and the like.

In the component (e), a phosphorus compound having at least one P—H bond in one molecule is compounded for improving the flame retardancy, and 9,10-dihydro-9-oxa is added. -10-phosphaphenanthrene-10
Oxide, 6-methyl-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide,
2,6,8-tritert-butyl-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10
Oxide, 6,8-dicyclohexyl-9,10-dihydro-9-oxa-10-phosphaphenanthrene-1
0-oxide, 6-phenyl-9,10-dihydro-9-
Examples thereof include, but are not limited to, oxa-10-phosphaphenanthrene-10 oxide, diethylphosphine oxide, diphenylphosphine oxide, and the like. 10-dihydro-9-oxa-10-
Preferred are phosphaphenanthrene-10 oxide, 6-phenyl-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10 oxide, diphenylphosphine oxide and the like.
O-dihydro-9-oxa-10-phosphaphenanthrene-10 oxide and diphenylphosphine oxide are preferred.

Compounds having at least two epoxy groups in the molecule include bisphenol A type epoxy, bisphenol F type epoxy, bisphenol S type epoxy, phenol novolak epoxy, cresol novolak epoxy, naphthalene type epoxy and biphenyl type epoxy aromatic. Examples include, but are not limited to, N-glycidyl compounds derived from amines and heterocyclic nitrogen bases, such as N, N-diglycidyl dianiline, triglycidyl isocyanurate, and the like. The mixing ratio of at least one P-
The content of the phosphorus compound having an H bond is preferably 0.1 to 10% by weight. When the content is 0.1% by weight or less, the effect of controlling the progress of curing is not obtained.

In addition to the above components, fused silica, crystalline silica, calcium carbonate, aluminum hydroxide, alumina, clay, barium sulfate, mica, talc, and the like are used for improving the coefficient of linear expansion, heat resistance, and flame resistance. Inorganic fillers such as white carbon and E glass fine powder may be blended in an amount of 40% by weight or less based on the resin content. If the content is more than 40% by weight, the viscosity of the interlayer insulating resin increases, and the embedding property between the inner layer circuits is reduced.

Further, a silane coupling agent such as epoxy silane or a titanate coupling agent for improving adhesion to a copper foil or an inner layer circuit board or improving moisture resistance, an antifoaming agent for preventing voids, Alternatively, a liquid or fine powder type flame retardant can be added. As the solvent, one that does not remain in the adhesive after the adhesive is applied to the copper foil and dried at 80 ° C. to 130 ° C. must be selected. For example, acetone, methyl ethyl ketone, toluene, xylene, n-hexane, methanol, ethanol, methyl cellosolve, ethyl cellosolve, methoxypropanol, cyclohexanone and the like are used.

The copper foil with an interlayer insulating adhesive is adhered by applying an adhesive varnish in which an adhesive component is dissolved in a predetermined solvent at a predetermined concentration to an anchor surface of the copper foil and then drying at 80 ° C. to 130 ° C. It is prepared so that the volatile component in the agent is 4.0% or less based on the resin. The volatile component is preferably from 3.0 to 1.5%. The thickness of the resin is preferably 100 μm or less, and if it exceeds 100 μm, the thickness will vary, making it impossible to secure a uniform insulating layer.

This copper foil with an interlayer insulating adhesive is laminated on an inner circuit board by a usual vacuum press or a laminator and cured, whereby a multilayer printed wiring board having an outer circuit can be easily formed.

[0019]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. First, a synthesis example of the organic phosphorus-containing compound as the component (c) will be described. Next, examples in which these organic phosphorus-containing compounds are blended to prepare an interlayer insulating adhesive for a multilayer printed wiring board will be described.

<Synthesis Example 1> 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10 was placed in a four-necked flask equipped with a thermometer, a stirrer, and a condenser.
100 parts of oxide (all amounts are parts by weight)
And 184.3 parts of cresol novolak epoxy resin, and reacted at 130 to 135 ° C. for 6 hours to obtain a product (a).
I got Elemental analysis revealed a phosphorus content of 5.1%.
The epoxy equivalent was 658.

<Synthesis Example 2> 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10 was placed in a four-necked flask equipped with a thermometer, a stirrer, and a condenser.
100 parts of oxide (HCA manufactured by Sanko Chemical Co., Ltd.) and phenol novolak epoxy resin (epoxy equivalent: 165;
152.8 parts of Nippon Kayaku Co., Ltd. (EPPN501H) was added, and reacted at 130 to 135 ° C. for 3 hours to produce a product (b).
I got Elemental analysis revealed a phosphorus content of 5.7%.
The epoxy equivalent was 636.

<Example 1> 50 parts of a hydroxyl-terminated polyether sulfone (weight average molecular weight: 24,000), bisphenol A type and bisphenol S type epoxy resin (weight average molecular weight: 34,000, bisphenol A:
Bisphenol S (molar ratio) = 8: 3) 30 parts, brominated phenol novolak type epoxy resin 15 parts (epoxy equivalent 285), bisphenol F type epoxy resin (epoxy equivalent 175) 10 parts, reaction obtained in Synthesis Example 1 The product (a) and 5 parts were stirred and dissolved in a mixed solvent of MEK and DMF, and 5 parts of 2-methylimidazole as a curing agent was added thereto.
An adhesive varnish was prepared by adding 0.2 parts by weight of a titanate coupling agent and 20 parts of calcium carbonate. This adhesive varnish was applied to an anchor surface of a copper foil having a thickness of 18 μm with a comma coater to obtain a copper foil with an adhesive having a total dried resin thickness of 80 μm.

Further, the thickness of the base material is 0.1 mm, and the thickness of the copper foil is 35 μm.
The glass-epoxy double-sided copper-clad laminate was subjected to pattern processing to obtain an inner circuit board. After the copper foil surface was blackened, the copper foil with the adhesive was set on both sides, and 1.6 mm between each laminate.
Insert a stainless steel mirror plate, put 15 sets in one stage,
Using a vacuum press, heating rate 3-10 ° C / min, pressure 10
~30Kg / cm ^2, the degree of vacuum -760~-730mmH
g under heat and pressure, and the temperature of
For more than a minute, a multilayer printed wiring board was manufactured.

Example 2 A multilayer printed wiring board was produced in the same manner as in Example 1 except that 15 parts by weight of bisphenol A novolak resin (having a hydroxyl equivalent of 120) was used as a curing agent.

Example 3 A multilayer printed wiring board was obtained in the same manner as in Example 1 except that the amount of the reaction product (a) obtained in Synthesis Example 1 was changed to 50 parts.

Example 4 Amorphous thermoplastic resin containing a sulfur component was prepared from polysulfone (weight average molecular weight: 26,000),
A multilayer printed wiring board was obtained in the same manner as in Example 1, except that the reactant (a) obtained in Synthesis Example 1 was changed to the reactant (b) obtained in Synthesis Example 2.

Comparative Example 1 Except for the bisphenol A-type and bisphenol S-type copolymerized epoxy resins, a hydroxyl-terminated polyether sulfone (weight average molecular weight 2400)
A multilayer printed wiring board was obtained in the same manner as in Example 1, except that 0) was changed to 80 parts.

Comparative Example 2 Example 1 was repeated except that the bisphenol A type and bisphenol S type copolymerized epoxy resins (average molecular weight: 34000) were changed to 80 parts, except for the polyether sulfone modified at the terminal hydroxyl group (weight average molecular weight: 24,000). In the same manner as in the above, a multilayer printed wiring board was obtained.

Comparative Example 3 A multilayer printed wiring board was obtained in the same manner as in Example 1 except that the reactant (a) obtained in Synthesis Example 1 was omitted.

With respect to the obtained multilayer printed wiring board, the glass transition temperature, the molding void, the variation in the thickness of the insulating layer, and the water absorption were measured, and the results are shown in Table 1.

[0031]

[Table 1]

(Measurement method) Inner layer circuit board test piece: line width (L) / line interval (S) = 1
20 μm / 180 μm fine wire circuit, clearance holes (1 mmφ and 3 mmφ), and 2 mm width 2 mm
There is a copper foil part with a line width of 3 mm between the slits. 1. Glass transition temperature: By the loss tangent of the dynamic viscoelasticity measurement. 2. Molded voids: The presence or absence of voids in the inter-circuit portion and the clearance hole portion was visually observed. The moldability was confirmed immediately after coating the resin on the copper foil and at 20 ° C / 60% R.
The test was performed twice after being left for 2 months under the H condition. 3. Variation in the thickness of the insulating layer on the inner layer circuit: Cross-section observation, the observation site is the line (circuit) part of the fine wire circuit and the insulating layer thickness of the copper foil part between the slits is measured at n = 5, and the average difference between each is insulated. The thickness was varied. 4. 4. Water absorption: according to JIS C6481 Flame retardancy: Shows the total flaming combustion time t1 + t2 according to JIS C6481.

[0033]

The interlayer insulating adhesive for multilayer printed wiring boards of the present invention has excellent flame retardancy and heat resistance and excellent storage stability despite having an insulating layer without glass cloth.
A multilayer printed wiring board with small variations in the thickness of the insulating resin between circuit layers can be easily manufactured.

Continued on the front page (72) Inventor Masataka Arai 2-5-8 Higashishinagawa, Shinagawa-ku, Tokyo F-term in Sumitomo Bakelite Co., Ltd. (reference) 4J004 AA02 AA11 AA13 AA17 AB05 CA08 CC02 FA05 4J040 EC001 EC002 EC061 EC062 EC071 EC072 EC161 EC162 EC172

Claims (6)

[Claims] 1. An interlayer insulating adhesive for a multilayer printed wiring board, comprising the following components as essential components. (A) an amorphous thermoplastic resin containing a sulfur component having a weight average molecular weight of 10 ³ to 10 ⁵ , (b) an epoxy resin or a phenoxy resin containing a sulfur component having a weight average molecular weight of 10 ³ to 10 ⁵ , (c)
A polyfunctional epoxy resin having an epoxy equivalent of 500 or less; (d) an epoxy curing agent; and (e) a phosphorus compound having at least one PH bond in one molecule and a compound having at least two epoxy groups in the molecule. Reactants. 2. The interlayer insulating adhesive according to claim 1, wherein the component (a) is polysulfone and / or polyethersulfone. 3. The multilayer print according to claim 1, wherein the component (b) is a bisphenol S type epoxy resin or phenoxy resin, or a copolymerized epoxy resin of bisphenol S type and bisphenol type or biphenyl type or phenoxy resin. Interlayer insulating adhesive for wiring boards. 4. The multilayer print according to claim 1, wherein the component (c) is at least one member selected from bisphenol type, novolak type, alicyclic and aminophenol type epoxy resins. Interlayer insulating adhesive for wiring boards. 5. A phosphor compound having at least one P—H bond in one molecule as the component (e) is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-
The interlayer insulating adhesive for a multilayer printed wiring board according to claim 1, which is 10-oxide. 6. A copper foil with an interlayer insulating adhesive for a multilayer printed wiring board, wherein the copper foil is coated with the interlayer insulating adhesive according to claim 1, 2, 3, 4, or 5.