JP2001251059A - Insulating material for multilayer printed wiring board and multilayer printed wiring board using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide insulating material for a multilayer printed wiring board wherein clear, uniform and fine anchors can be formed and insulating resin having spreadability is main component. SOLUTION: In the insulating material, hardened substance fine powder wherein thermosetting resin which can be roughened to acid or oxidizing agent and silica filler are uniformly dispersed and then hardened is dispersed in matrix which is hard to dissolve in the acid or oxidizing agent. It is preferable that polyether sulfone is used as the matrix.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating material for a multilayer printed wiring board having excellent electroless plating properties and coating properties, and more particularly to an electroless plating material having excellent adhesion between a substrate and an electroless plating film. The present invention relates to a multilayer printed wiring board having a fine pattern suitable for plating and an insulating material for an interposer for a semiconductor package.

[0002]

2. Description of the Related Art In recent years, with the progress in the electronics field, electronic devices have been reduced in size and speed, and therefore, even in packages for directly mounting ICs and LSIs, high density and high reliability by fine patterns have been required. Desired.

Conventionally, in a package on which an LSI or the like is mounted, electrical reliability is insufficient due to a crack or the like at a junction boundary due to a difference in thermal expansion coefficient between the LSI and an interposer (mounting substrate). There was a problem.

Therefore, attempts have been made to reduce the thermal expansion coefficient of the interposer by adding a silica filler to the interposer, thereby reducing the difference in linear expansion coefficient between the mounted object and the mounted object. In addition, cracks also occur in the interposer itself due to a severe durability test, and improving the toughness of an insulating material used for a mounting substrate has also been a problem.

In recent years, a technique has been developed to improve the insulating epoxy resin by imparting toughness to the resin by using a mixed system of a thermoplastic resin such as polyether sulfone and epoxy as a resin component (Keizo Yamanaka). and Takashi
Inoue, Polymer, vol. 30, p. 662 (1989)).

[0006] The polyethersulfone-modified epoxy resin obtained by mixing two types of resins has improved toughness as compared with the epoxy-only resin. The reason for this is that the structures are in a state of being connected to each other and dispersed regularly, and form a so-called co-continuous structure of epoxy resin and polyether sulfone.

In recent years, such a resin substrate has been used not only as a high-density printed wiring board but also as a substrate for mounting a semiconductor bare chip since it is lightweight and inexpensive. Is becoming more and more advanced. For this reason, if the unevenness of the surface anchor for obtaining the adhesion strength is increased, the uniformity and reliability of the thin wire conductor circuit are impaired, and there has been a problem that the thinning and the adhesion strength cannot be achieved at the same time.

On the other hand, in order to apply these insulating materials having improved toughness to a multilayer printed wiring board, when a polyether sulfone, an epoxy resin and a silica filler are mixed and cured simultaneously as the thermoplastic matrix, Is preferentially incorporated into the epoxy-rich phase and hardly incorporated into the polyethersulfone-rich phase. That is, the phase separation structure when the silica filler is added becomes extremely distorted compared to the phase separation structure composed of only the polyether sulfone and the epoxy resin.

Therefore, when the cured resin is roughened with an oxidizing agent, the roughened surface of the resin has large uneven spots because the dispersibility of the silica filler which is easily roughened by the oxidizing agent is not uniform. become. That is, not only unevenness occurs in the adhesion strength between the substrate and the electroless plating film, but also the roughened surface is too rough to form a conductor layer required for high-density mounting with a fine line.

[0010]

According to the present invention, since the dispersibility of the silica filler is uniform, the formation of a roughened surface of the resin is improved, the adhesion strength between the substrate and the electroless plating film is excellent, and An object of the present invention is to provide an insulating material for a multilayer printed wiring board, which can form a conductor layer required for high-density mounting on a fine line, and a multilayer printed wiring board using the same.

[0011]

Means for Solving the Problems The inventors of the present invention have made intensive studies to overcome the above-mentioned problems, and as a result, claim 1 shows that a thermosetting resin and a silica filler which can be roughened with respect to an acid or an oxidizing agent are used. An insulating material for a multilayer printed wiring board, characterized in that a finely divided cured product powder that is uniformly dispersed and cured in advance is dispersed in a thermoplastic resin matrix having a property of being hardly soluble in an acid or an oxidizing agent. is there. In a preferred embodiment, the thermosetting resin comprises at least a polyfunctional epoxy compound and a curing agent.
3. The insulating material for a multilayer printed wiring board according to item 1. A third aspect of the present invention is the printed wiring board insulating material according to the first or second aspect, wherein polyether sulfone is used for the thermoplastic resin matrix. According to a fourth aspect of the present invention, the cured product fine powder is mixed at a ratio of 55 to 85% by weight based on the total solid content of the insulating material.
4. The multilayer printed wiring board insulating material according to any one of 1. to 3. It is preferable that the ratio of silica constituting the fine powder of the cured product is 5 to 5.
5. The insulating material for a multilayer printed wiring board according to claim 1, wherein the content is 40% by weight. A sixth aspect of the present invention is the insulating material for a multilayer printed wiring board according to any one of the first to fifth aspects, wherein the average particle size of the fine powder of the cured product is 0.5 μm to 6 μm. A seventh aspect of the present invention is a multilayer printed wiring board using the insulating material according to any one of the first to sixth aspects.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The multilayer printed wiring board of the present invention has a silica filler previously dispersed in an epoxy resin which is a thermosetting resin, and by preparing a heat-resistant resin fine powder obtained by curing to a desired particle size, for enhancing toughness. It is intended to obtain an excellent insulating material for a multilayer printed wiring board which can form a uniform film with a polyether sulfone which is a thermoplastic resin matrix and can form a fine surface roughened state by an oxidizing agent. .

The thermosetting resin described in the present invention includes various resins such as a urethane resin and a polyimide resin. However, it is relatively inexpensive and has excellent insulating properties and plating properties. A cured product of an epoxy resin composed of an agent is particularly desirable.

The polyfunctional epoxy compounds described in the present invention include, for example, phenol novolak type epoxy resin, cresol novolak type epoxy resin, DPP novolak type epoxy resin, biphenyl type epoxy resin, cyclopentadienyl type epoxy resin, biphenyl novolak type epoxy resin , Trishydroxyphenylmethane type epoxy resin, tetraphenylolethane type epoxy resin, dicyclopentadienephenol type epoxy resin, naphthalene type epoxy resin, tris (glycidylphenyl) methane, tetraglycidyldiaminodiphenylmethane, triglycidylparaaminophenol, triglycidyl Various polyfunctional such as metaaminophenol, tetraglycidyl metaxylylenediamine, tetraglycidylbisaminomethylcyclohexane Glycidylamine type epoxy compounds, 2,2 ', 4,4'-tetraglydoxybiphenyl and the like, and polyfunctional alicyclic epoxy compounds such as phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A type Epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, biphenyl epoxy resin, biphenyl novolak epoxy resin, trishydroxyphenylmethane epoxy resin, tetraphenylolethane epoxy resin, dicyclopentadiene phenol epoxy resin, etc. And hydrogenated compounds of epoxy compounds containing an aromatic ring, alicyclic epoxy resins, and various derivatives of cyclohexene oxide. These can be used alone or in combination.

As the curing agent described in the present invention, those known as general epoxy curing agents can be used. For example, amine curing agents, phenolic resin curing agents, cresol resin curing agents, imidazole curing agents,
Examples include various amine-based curing agents and various carboxyl compounds such as carboxylic acids and carboxylic anhydrides, and are not particularly limited.

As the silica filler described in the present invention, various kinds of silica such as various synthetic silicas synthesized by a wet method, a dry method, crushed silica obtained by crushing silica, and fused silica once melted can be used. In particular, when high-density wiring is required, it is particularly desirable that the silica has a particle diameter of 5 μm or less.

The thermoplastic resin described in the present invention includes polyester, polyether, polyphenylene ether, polyimide, polyamide, polyimideamide, polysulfone,
Various heat-resistant resins such as polyaramid,
Glass transition point, mechanical properties, which are indicators of heat resistance of resin,
Polyethersulfone is particularly desirable in various points such as insulation and solubility in a solvent.

The proportion of the cured product fine powder and the thermoplastic resin matrix described in the present invention is particularly preferably such that the cured product fine powder is mixed in the range of 55 to 85% by weight based on the total solid content of the insulating material. desirable. The reason for this is that if the content is less than 55% by weight, the components which are not roughened by the oxidizing agent increase, so that sufficient plating strength of the conductor pattern cannot be obtained. On the other hand, when the content is 85% by weight or more, the toughness effect improved by the addition of the thermoplastic resin is poor, and problems such as substrate cracks occur.

The proportion of the silica filler contained in the fine powder of the cured product described in the present invention is desirably 5 to 40% by weight. The reason for this is that if the proportion of the silica filler is 5% by weight or less, it is difficult to obtain a sufficient roughening effect in the surface roughening step using an oxidizing agent or the like because the resin is rich in epoxy resin.
If the content is 40% by weight or more, the fine particles of the cured product become brittle, which causes a problem in reliability.

The average particle size of the fine powder of the cured product described in the present invention is preferably in the range of about 0.5 to 6 μm. The reason for this is that if the thickness is 0.5 μm or less, the anchoring effect of the roughened surface after the surface roughening step is poor, and the plating strength may be reduced. The roughened surface is too rough, which causes a problem in thinning the conductor pattern.

As a method for obtaining the fine powder of the cured product described in the present invention, a silica filler is sufficiently dispersed in a mixed solution in which a suitable solvent, a polyfunctional epoxy compound and a curing agent are dissolved, and the mixture is cured. To obtain a desired particle size. In addition, there is a method in which a poor solvent in which a polyfunctional epoxy and a curing agent are not dissolved, and a method in which a mixture of these is cured with vigorous stirring, and then the solvent is removed and dried.

The insulating resin composition may further contain an epoxy group curing accelerator, a thermal polymerization inhibitor, a plasticizer, a leveling agent, a defoaming agent, an ultraviolet absorber, a flame retardant, etc., if necessary. It is possible to add an additive or a coloring pigment.

Next, a method for manufacturing a multilayer printed wiring board using the insulating material of the present invention will be specifically described.

The present invention starts by forming the above-mentioned insulating layer on a substrate on which a conductor circuit is formed.

As the substrate used in the present invention, for example, a plastic substrate, a ceramic substrate, a metal substrate, a film substrate and the like can be used. Specifically, a glass epoxy substrate, a bismaleimide-triazine substrate, an aramid fiber non-woven substrate , Liquid crystal polymer substrate, aluminum substrate,
An iron substrate, a polyimide substrate, or the like can be used.

As a method of forming the resin insulating layer on the substrate on which the conductor circuit is formed, for example, a roller coating method, a dip coating method, a spray coating method, a spinner coating method, a curtain coating method, a slot coating method, and the like are used. Coating method, a method of applying by various means such as screen printing method, or the mixed solution was processed into a film,
A method of attaching a resin film can be applied.
Further, the preferred thickness of the resin insulating layer in the present invention is:
Usually, it is about 20 to 10000 μm, but it is possible to increase the thickness more particularly when high insulating properties are required.

After applying the insulating material to the substrate on which the conductive circuit is formed, the substrate is dried and thermally cured to obtain
A resin insulating layer is formed.

The multilayer printed wiring board is manufactured by forming a conductive circuit by subjecting the surface of the resin insulating layer to a surface roughening treatment using an acid or an oxidizing agent, and then performing electroless plating and electrolytic plating. You. As a method of the electroless plating, for example, it is preferable to use at least one of electroless copper plating, electroless nickel plating, electroless gold plating, electroless silver plating, and electroless tin plating. In addition to the above-mentioned electroless plating, different types of electroless or electrolytic plating can be further performed, or solder can be coated.

Further, if necessary, the insulating material of the present invention can be applied to a copper foil in a semi-cured state in advance and used as a copper-clad laminate.

It is to be noted that a conductive circuit can be formed using the insulating resin composition of the present invention by various methods conventionally used for printed wiring boards.
A method of etching a circuit after performing electroless and electrolytic plating on a substrate, a method of directly forming a circuit when performing electroless plating, and the like can be applied. By forming an insulating layer using the resin composition of the present invention, a multilayer printed wiring board having an electroless plated film formed with high reliability can be provided easily and at low cost.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment for manufacturing a multilayer printed wiring board using the insulating material of the present invention will be described below.

Example 1 First, a heat-resistant epoxy resin (T
MH / Sumitomo Chemical Co., Ltd. product name) 97.2 parts by weight, silica filler 51.8 parts by weight, phenolic resin (Nippon Kayaku Co., Ltd.) 47.9
The parts by weight were added to the γ-butyrolactone solvent and mixed for 1 hour with a paint shaker. Next, a heat curing treatment was performed at 180 ° C. for 2 hours using a drying oven to obtain a cured product. The cured product is coarsely pulverized, and then finely pulverized using a supersonic jet pulverizer while being frozen with liquid nitrogen, and further classified using an air classifier, to obtain an epoxy resin fine powder having an average particle size of about 2 μm. I got

196.9 parts by weight of this fine powder, 62.2 parts by weight of polyether sulfone (manufactured by Sumitomo Chemical Co., Ltd.), curing catalyst 2E
9.7 parts by weight of 4MZ (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to a γ-butyrolactone solvent, and the mixture was stirred and defoamed to obtain a coating liquid for an insulating material.

Next, this insulating material coating solution is applied to a blackened glass-epoxy substrate with a spin coater to a thickness of about 50 μm, and then dried at 180 ° C. using a drying oven.
Heat curing treatment was performed for 2 hours to form a resin insulating layer. The substrate on which the resin insulating layer was formed was subjected to copper plating with a thickness of about 18 μm in a normal copper plating step of a printed circuit board, to obtain a printed wiring board. The adhesion strength was examined by a 90-degree peel test of a 1 cm wide pattern based on JIS-C6481. Further, a resin insulating layer film sample having a thickness of 50 μm was prepared by the same resin insulating layer forming method, and the glass transition point Tg was measured by a dynamic viscoelasticity measuring apparatus DMA. In order to observe the conductor circuit shape of the fine wire pattern, the plating conductor layer was set to L / S = 20/20.
The pattern was patterned to μm, and the edge shape of the pattern was observed with an optical microscope. Further, a counter electrode pattern having a diameter of about 10 mm is provided on each of the core layer and the built-up layer.
An insulation reliability test was performed using a CT tester under the conditions of 121 ° C., 85%, and 20 V. The results are shown in Table 1.

[0035]

[Table 1]

Example 2 First, an epoxy resin (E5050 /
Yuka Shell Co., Ltd.) 114.7 parts by weight, silica filler
51.8 parts by weight and 30.4 parts by weight of a phenol resin (manufactured by Nippon Kayaku Co., Ltd.) were added to a γ-butyrolactone solvent, mixed for 1 hour with a paint shaker, and then dried in a drying oven for 18 hours.
Heat curing treatment was performed at 0 ° C for 2 hours to obtain a cured product. While coarsely pulverizing this cured product, and then freezing with liquid nitrogen,
Fine pulverization was performed using a supersonic jet pulverizer, and further classification was performed using an air classifier to obtain an epoxy resin fine powder.

196.9 parts by weight of this fine powder, 62.2 parts by weight of polyether sulfone (manufactured by Sumitomo Chemical Co., Ltd.), curing catalyst 2E
11.5 parts by weight of 4MZ (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to a γ-butyrolactone solvent, and the mixture was stirred and defoamed to obtain an insulating material coating liquid.

Next, in Example 1, an insulating material coating liquid was used.
A printed wiring board was obtained in the same manner as described above.

Example 3 First, a heat-resistant epoxy resin (E
97.1 parts by weight of OCN103S / Nippon Kayaku Co., Ltd., 51.8 parts by weight of silica filler, 48.1 phenolic resin (Nippon Kayaku)
Add parts by weight to γ-butyrolactone, mix for 1 hour with a paint shaker, and then use a drying oven for 18 hours.
Heat curing treatment was performed at 0 ° C for 2 hours to obtain a cured product. While coarsely pulverizing this cured product, and then freezing with liquid nitrogen,
Fine pulverization was performed using a supersonic jet pulverizer, and further classification was performed using an air classifier to obtain an epoxy resin fine powder.

197 parts by weight of this fine powder, 62.2 parts by weight of polyether sulfone (manufactured by Sumitomo Chemical Co., Ltd.) and 9.7 parts by weight of catalyst 2E4MZ (manufactured by Tokyo Chemical Industry Co., Ltd.) were added to γ-butyrolactone, followed by stirring and defoaming. Then, an insulating material was obtained.

Next, a printed wiring board was obtained in the same manner as in Example 1 using an insulating material.

Comparative Example 1 A heat-resistant epoxy resin (E5050 /
114.7 parts by weight, 62.2 parts by weight of polyether sulfone (manufactured by Sumitomo Chemical Co., Ltd.), 51.8 parts by weight of silica filler, 30.4 parts by weight of phenol resin (manufactured by Nippon Kayaku Co., Ltd.), catalyst 2E4MZ (Tokyo Chemical 11.5 parts by weight of γ-
After mixing for 1 hour with a paint shaker in addition to butyrolactone, the mixture was heat-cured at 180 ° C. for 2 hours using a drying oven to obtain a cured product.

Next, a printed wiring board was obtained in the same manner as in Example 1 using an insulating material.

The roughened surface of the insulating material obtained in Examples 1 to 3 was uniform, but the roughened surface of the insulating material obtained in Comparative Example 1 had roughened spots.

Table 1 shows the results of measuring the peel strength indicating the adhesive strength between the insulating layer and the conductive layer in the insulating materials obtained in Examples 1 to 3 and Comparative Example 1.

Although the compositions of Example 1 and Comparative Example 1 are the same, it can be seen that the peel strength of Example 1 is superior to that of Comparative Example 1. From this, it can be said that, by uniformly dispersing the silica filler, a clear anchor was easily formed, and an insulating material having excellent adhesive strength between the insulating layer and the conductive layer could be obtained.

The inventors of the present invention have conducted studies by changing the mixing method of silica filler, epoxy and polyethersulfone. As a result, in order to uniformly disperse the silica filler in the insulating material, the silica filler was uniformly dispersed in the epoxy beforehand. It has been found that it is preferable to disperse the cured fine powder in polyethersulfone and cure it.

That is, by dispersing a fine powder in which a silica filler is uniformly dispersed in an epoxy in advance in a polyethersulfone, it is possible to prevent the silica filler from entering a polyethersulfone-rich phase and easily entering an epoxy phase. It has been found that the silica filler is uniformly dispersed throughout the insulating material.

[0049]

As described above, the present invention solves the above-mentioned problems of the conventional multilayer printed wiring board, and has a high heat resistance and a highly reliable multilayer such as copper wire adhesion. The present invention can provide an insulating resin composition for a multilayer printed wiring board, which can easily and inexpensively produce a printed wiring board without imposing a great burden on the environment.

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Claims (7)

[Claims] 1. A fine powder of a cured product obtained by uniformly dispersing and curing a thermosetting resin and a silica filler which can be roughened with respect to an acid or an oxidizing agent beforehand becomes hardly soluble in an acid or an oxidizing agent. An insulating material for a multilayer printed wiring board, wherein the insulating material is dispersed in a thermoplastic resin matrix having characteristics. 2. The thermosetting resin according to claim 1, wherein said thermosetting resin comprises at least a polyfunctional epoxy compound and a curing agent.
4. The insulating material for a multilayer printed wiring board according to the above. 3. The thermoplastic resin matrix according to claim 1, wherein polyether sulfone is used.
2. The printed wiring board insulating material according to 1. 4. The multilayer printed wiring according to claim 1, wherein said hardened material fine powder is mixed at a ratio of 55% by weight to 85% by weight based on the total solid content of the insulating material. Board insulation material. 5. The insulating material for a multilayer printed wiring board according to claim 1, wherein the proportion of silica constituting the fine powder of the cured product is 5 to 40% by weight. 6. The fine powder of the cured product has an average particle size of 0.5 μm or less.
The insulating material for a multilayer printed wiring board according to claim 1, wherein the thickness is 6 μm. 7. A multilayer printed wiring board using the insulating material according to any one of claims 1 to 6.