JP2508389B2 - Laminated board and manufacturing method thereof - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated board suitable as a substrate for a printed wiring board on which surface mount components (SMD) are mounted, and a manufacturing method thereof.

2. Description of the Related Art As electronic / electrical devices are becoming denser, more highly integrated, and smaller, the components to be mounted on the printed wiring boards to be soldered and soldered from insertable discrete components to surface mount type components are also available.
SMD is increasing. As a substrate for printed wiring boards, a laminated board is used in which sheet-like base materials impregnated with a thermosetting resin are stacked and heat-pressed.However, as an SMD-compatible substrate, SMD solder is used after repeated cooling and heating cycles. It is desirable to use a laminated plate having a low elastic modulus that can prevent cracks from occurring at the connection portion.

 As means for reducing the elastic modulus of the laminated plate, (1) a flexibility-imparting agent is dispersed in a thermosetting resin.

(2) A flexibility-imparting agent is reacted with the thermosetting resin. Etc. are being considered.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the above-mentioned conventional technology, the elastic modulus of the laminated plate is reduced,
It is possible to reduce the internal stress when the laminate expands and contracts in the plane direction in the cooling / heating cycle, but the glass transition temperature of the resin that constitutes the laminate decreases, the rigidity during heating decreases, and the chemical resistance also increases. It gets worse. The deterioration of these characteristics becomes an obstacle when the laminated board is processed as a substrate of a printed wiring board.

The problem to be solved by the present invention is a laminated plate using a glass nonwoven fabric as a part or all as a base material impregnated with a resin, while achieving a low elastic modulus, a glass transition temperature, a rigidity during heating, It is to suppress the deterioration of chemical resistance.

Furthermore, it is also necessary to improve heat resistance and moisture resistance of the laminated plate.

Means for Solving the Problems In a laminated board according to the present invention, a thermosetting resin A impregnated in a glass nonwoven fabric is mixed with an inorganic filler coated with a thermosetting resin B having a tensile elastic modulus lower than that of the resin A. It is characterized by having done. The laminated plate may have a metal foil integrally attached to the surface thereof.

A feature of the laminated plate manufacturing method is that the varnish of the thermosetting resin A to be impregnated into the glass nonwoven fabric is coated with the thermosetting resin B having a lower tensile elastic modulus than the resin A, and the resin B is This is the point of incorporating a completely cured inorganic filler. Before the inorganic filler is coated with the resin B,
The surface is preferably treated with a silane coupling agent.

Action In the laminated board according to the present invention, the resin B having a lower tensile elastic modulus than the resin A acts to relax stress at the interface between the resin A and the inorganic filler, and the elastic modulus of the entire laminated board can be lowered.

Resin B was directly blended with Resin A and dispersed in Resin A,
In the so-called sea-island structure (resin A is the sea part and resin B is the island part) in a non-uniform binary system, the resins A and B have different free volume fractions and therefore different glass transition temperatures. However, the mechanical behavior is also a composite of two components. However, in a system in which a hard inorganic filler is dispersed in a resin such as the laminated plate according to the present invention, mechanical properties such as glass transition temperature are similar to those of the resin A which is a sea component. It is presumed that there is no decrease in rigidity during heating.

When the resin B coated with the inorganic filler is completely cured and then added to the varnish of the resin A, the resin B does not dissolve into the varnish and does not participate in the crosslinking reaction of the resin A. The original characteristics of the resin A are not impaired. Further, by completely curing, there is no deterioration due to moisture absorption and the storage stability of the resin B-coated inorganic filler is good.

Example Next, an example according to the present invention will be described.

The magnitude of the elastic modulus of the low-elasticity thermosetting resin B is determined by relative comparison with the elastic modulus of the thermosetting resin A.
Examples of the thermosetting resin B include tung oil-modified phenol resin, butyral-modified phenol resin, nitrile-modified phenol resin, vinylphenol-modified epoxy resin, nitrilephenol-modified epoxy resin and flexible epoxy resin.

The inorganic filler is aluminum hydroxide, talc, alumina, magnesia, silica or the like.

Example 1 As a resin B, a polyvinyl butyral modified phenolic resin was prepared, and this was mixed with methyl ethyl ketone / toluene =
It was dissolved in a solvent of 50/50 to prepare a solution having a resin content of 2% by weight.

While stirring the aluminum hydroxide with a mill, the above solution was added dropwise so that the resin content was 2% by weight with respect to the weight of the aluminum hydroxide. Then, it was dried at 130 ° C. for 1 hour to obtain an aluminum hydroxide whose surface was coated with a completely cured polyvinyl butyral-modified phenol resin.

Then, a resin varnish to be impregnated into a glass nonwoven fabric (50 g / m ² ) was prepared with the following composition.

(1) Brominated epoxy resin 100 parts by weight (2) Phenol novolac resin 20 parts by weight (3) Curing accelerator (2E4MZ) 0.1 parts by weight (4) Aluminum hydroxide 90 parts by weight (5) Acetone 40 parts by weight Glass non-woven fabric base The resin varnish was impregnated and dried into a material to prepare a prepreg I having a resin content of 88% by weight, while a similar resin varnish containing no aluminum hydroxide was impregnated into a woven glass cloth (205 / m ² ) and dried to obtain a resin. An amount of 40% by weight of prepreg II was prepared.

6 plies of prepreg I are piled up and prepregs on both sides
Two-layer copper clad laminate having a thickness of 1.6 mm was obtained by laminating 1 ply of II, placing 18 μm copper foil on the outermost surface, and subjecting it to heat and pressure molding.

Example 2 A double-sided copper-clad laminate was obtained in the same manner as in Example 1 except that the polyvinyl butyral-modified phenol resin content was 5% by weight with respect to the weight of aluminum hydroxide.

Example 3 Double-sided copper-clad laminate was carried out in the same manner as in Example 2 except that aluminum hydroxide was treated with aminosilane (3% by weight based on the weight of aluminum hydroxide) and then coated with polyvinyl butyral modified phenolic resin. I got a plate.

Example 4 A double-sided copper-clad laminate was obtained in the same manner as in Example 1 except that the polyvinyl butyral-modified phenol resin content was 10% by weight with respect to the weight of aluminum hydroxide.

Example 5 Instead of the polyvinyl butyral modified phenolic resin,
Flexible epoxy resin (glyceryl dimer acid)
A double-sided copper-clad laminate was obtained in the same manner as in Example 2 except that was used.

Example 6 Double-sided copper-clad as in Example 5 except that aluminum hydroxide was treated with epoxysilane (3% by weight based on the weight of aluminum hydroxide) and then coated with a flexible epoxy resin. A laminated board was obtained.

Conventional Example 1 A double-sided copper-clad laminate was obtained in the same manner as in Example 1 except that aluminum hydroxide was not coated with a polyvinyl butyral-modified phenol resin.

Conventional Example 2 In Conventional Example 1, a dimer acid-modified epoxy resin was used.
Part by weight was blended to participate in the curing reaction.

Comparative Example 1 Instead of coating the aluminum hydroxide with the polyvinyl butyral modified phenolic resin in Example 2, the same amount of polyvinyl butyral modified phenolic resin was added to the brominated epoxy resin as the matrix resin, and the average particle size was 20 μm.
A double-sided copper-clad laminate was obtained in the same manner except that the particles were dispersed in a sea-island structure at m (Max. 40 μm, Min. 5 μ).

Comparative Example 2 In Example 5, instead of coating the aluminum hydroxide with the flexible epoxy resin, the same amount of the flexible epoxy resin was used in the brominated epoxy resin as the matrix resin, and the average particle size was 20 μm (Max. 40 μm). , Min. 5 μ), and a double-sided copper-clad laminate was obtained in the same manner except that it was dispersed in a sea-island structure.

Table 1 shows the characteristics of the laminated board in each of the above examples and the solder connection reliability when the laminated board was processed into a printed wiring board and SMD was mounted.

EFFECTS OF THE INVENTION As described above, the laminated plate according to the present invention achieves a low elastic modulus and has high solder connection reliability as an SMD-compatible substrate, but does not have a decrease in glass transition temperature or rigidity during heating. Since it has good chemical resistance, there is no problem in terms of characteristics when it is processed into a printed wiring board.

Further, the resin B will be uniformly dispersed in the resin A along with the dispersion of the inorganic filler in the resin A, and the particle size of the dispersion can be controlled only by selecting the particle size of the inorganic filler. You can It is difficult to uniformly disperse the resin B into the resin A in a sea-island structure.

By treating the surface of the inorganic filler with the silane coupling agent before coating the inorganic filler with the resin B, the moisture resistance and heat resistance of the laminate can be further improved.

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Claims (4)

(57) [Claims] Claims: 1. A laminated plate in which base materials impregnated with a thermosetting resin are superposed and integrated, and a part or all of the superposed base materials are made of glass non-woven fabric. Resin A is added to the thermosetting resin A
A laminate comprising an inorganic filler coated with a thermosetting resin B having a lower tensile elastic modulus. 2. The laminated plate according to claim 1, wherein a metal foil is integrated on at least one surface. 3. A method for manufacturing a laminate, which comprises stacking base materials impregnated with a varnish of thermosetting resin and superimposing them by heat and pressure molding, wherein a glass nonwoven fabric is used for a part or all of the base materials to be stacked. In, the varnish of thermosetting resin A to be impregnated into the glass nonwoven fabric is mixed with the thermosetting resin B having a lower tensile elastic modulus than that of the resin A, and the inorganic filler in which the resin B is completely cured is blended. A method for manufacturing a laminated board, comprising: 4. The method for producing a laminated board according to claim 3, wherein the surface of the inorganic filler is treated with a silane coupling agent before coating the inorganic filler with the resin B.