JP2924401B2 - Composite prepreg - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite prepreg particularly suitable for bonding for manufacturing a multilayer printed wiring board.

[0002]

2. Description of the Related Art A prepreg for a laminated board is prepared by impregnating a resin-impregnable fiber base material such as glass cloth with a thermosetting resin varnish, and heating the impregnated resin to a semi-cured state to a B stage. Manufactured. Stack several prepregs,
Heat and press with a press to make a laminate, and also place metal foil such as copper foil on both sides or one side of the stacked prepreg,
It is heated and pressed by a press to form a metal-clad laminate.

[0003] Prepreg is used for bonding and integrating components in the production of multilayer printed wiring boards. In other words, two prepregs are arranged on both sides of the inner layer board on which the circuit is formed, and further, copper foil is arranged on both outer layers thereof, and heated and pressed by a press. I have. The reason why two prepregs are arranged between components is that one prepreg lacks a resin component in order to fill irregularities caused by forming a circuit on the surface of a component (for example, an inner circuit board). Because. As a pressing method, there are a pin laminating method in which a component and a prepreg are not shifted using a pin, and a mass laminating method in which a component and a prepreg are stacked and pressed without using a pin.

In order to improve the adhesiveness between the prepregs, the optimum condition is selected by changing the B-stage state of the resin in the drying step of forming the resin into the B-stage, or changing the heating and pressing conditions in press molding. I have to.
A method for evaluating the adhesiveness of the laminate is, for example, JIS C 64
81 and JIS C 6486. That is, the test piece is dipped in the molten solder at 260 ° C., taken out after a predetermined time, and examined for abnormalities such as bulging of the substrate and measling.

[0005]

Incidentally, in any case of a laminate, a metal-clad laminate or a multilayer printed wiring board, there is a material construction work for combining a plurality of prepregs. Heretofore, this material construction operation has simply been performed by sequentially stacking one prepreg. For example, in order to obtain an insulating layer having a thickness of 0.2 mm between components of a multilayer printed wiring board, two prepregs having a thickness of 0.1 mm are stacked, and
To obtain an insulating layer with a thickness of 0.3 mm, a thickness of 0.1 m
m prepregs, or a combination of a prepreg having a thickness of 0.1 mm and a prepreg having a thickness of 0.2 mm.

As described above, since a plurality of prepregs are used, the longer the number of layers, the longer the time and the lower the efficiency of material construction work. Also, when configuring the inner layer plate and the prepreg by the pin lamination method, not only it takes time to insert the prepreg into the pins, but also the edge of the prepreg,
Resin powder scatters from the pin holes. If the scattered resin powder adheres to the surface of the inner layer circuit, it causes a void, and if it adheres to the surface of the outer layer copper foil, it causes a surface defect such as punching.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and among the work of material construction of a laminated board, the efficiency of work involving a prepreg is improved, and the generation of dust such as resin powder. an object of the present invention is to provide a less complex prepreg.

[0008]

According to the present invention, a plurality of stacked prepregs are thermocompression-bonded at a plurality of positions on the peripheral edge to form a composite prepreg 4. In a prepreg for a multi-layer printed wiring board, a plurality of prepregs provided with pin holes 1 for pin lamination are overlapped with the positions of the pin holes 1 aligned, and thermocompression-bonded at a hole peripheral portion 2 of the pin holes 1 to form a composite. It is referred to as prepreg 4.

The center of the pin hole 1 is desirably within 20 mm from the cut end of the prepreg. This is because the range in which a circuit can be formed is wide, and the range in which a circuit can be formed is not narrowed when the resin in the periphery of the pin hole 1 is melted by heat. Although the diameter of the pin hole 1 is determined by the diameter of the pin used in the pin lamination method, generally, it is preferably about 4 to 9 mm from the diameter of the pin used. In a normal case, the resin is melted around this hole over a width of about 5 mm. The range to be melted may be such that it does not peel off during handling of the prepreg. Regarding the prepreg for the pin lamination method, it is desirable to melt the resin around all the pin holes to form a composite.

[0010] Regarding the prepreg for the laminated plate and the mass laminating method having no pin hole, four sides are shown in FIG.
As shown in (1), the resin is melt-pressed at one location on each side to composite the prepreg. The method of melting the resin by heat is not particularly limited. For example, as shown in FIG.
There is a method of pressing the hole periphery and the end from above with a heated mold. As for the degree of melting, it is preferable that the resin does not flow into the hole in the case where the thermosetting resin is not completely cured and has a hole such as a prepreg for a pin lamination method. At least the hole diameter is 1 depending on the molten resin.
mm.

It is preferable to keep the heat for melting the resin to such an extent that the resin is not completely cured. Depending on the type of resin, the temperature of the resin is 80
C. to 170.degree. C., preferably
100 ° C to 150 ° C. By setting the degree of melting of the resin to such a degree that the thermosetting resin is not completely cured, it is possible to form the resin after press forming without leaving a trace of heat melting around the hole. The number of prepregs to be integrated is not particularly limited, but is preferably 4 or less, because it is easy to integrate.

[0012]

[Function] Since the prepreg is pre-compositely integrated, a plurality of bonded prepregs can be formed at a time during the material construction work of the laminate, so that the work time can be reduced and work involving prepregs can be easily performed. become. In the prepreg used for the pin laminating method, the resin in the pin hole and the surrounding area is melted, and the resin powder is prevented from scattering around the pin hole.

[0013]

【Example】

Example 90 parts by weight of a brominated bisphenol A type epoxy resin (Yuika Shell Co., Ltd., Epicoat 5040B80)
Cresol novolak epoxy resin (Dow Chemical Co., ECN1273) 10 parts by weight, dicyandiamide 1.5 parts by weight, 2-ethyl 4-methylimidazole 0.05
Methyl ethyl ketone was added to parts by weight to obtain an epoxy resin varnish.

The varnish is placed in an impregnating tank and has a thickness of 0.15.
A glass cloth having a thickness of 1 mm was impregnated with epoxy varnish and heated to form a B-stage resin to prepare a prepreg. Pin holes 1 having a diameter of 8.0 mm were punched out from the prepreg at four locations by punching. The prepregs piled two sheets, covering the tip 3 of the heating iron at tetrafluoroethylene sheet, FIG. 1
As shown in (b) , a heated iron tip 3 heated to 110 ° C. was pressure-bonded to the hole and its surroundings 2 for 5 seconds to obtain a composite prepreg 4.

Using this composite prepreg, as shown in FIG. 2 , the composite prepreg 4 is sandwiched between two inner layers 6,6.
And a copper foil 5 on the outside through a composite prepreg 4
And press-formed at a temperature of 175 ° C. and a pressure of 4 MPa for 90 minutes to obtain a 6-layer plate. As a result, the time required for the combination of the constituent materials was 55 seconds, and the time required for the combination of the prepregs was 21 seconds. In addition, there was almost no scattering of the resin powder when combined. After pressing, the presence or absence of voids and blurring was examined, but neither voids nor blurring were found.

Comparative Example In addition to using two non-composite prepregs, the components and the prepregs were combined in the same manner as in the examples, and then press-molded in the same manner. As a result, the time required for the combination of the constituent materials was 76 seconds, and the time required for the combination of the prepregs was 42 seconds. In addition, the resin powder was considerably scattered particularly around the holes during the construction.

[0017]

According to the present invention, by integrally combining a plurality of prepregs, the construction work becomes easy and the construction time can be shortened. Further, scattering of the resin powder from the hole provided in the prepreg and the periphery thereof is reduced, so that voids and indentation defects caused by the resin powder can be reduced. The effect is great when the composite prepreg of the present invention is used when combining the constituent materials of the multilayer printed wiring board by the pin lamination method.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, wherein (a) is a perspective view of a composite prepreg for a laminated board, and (b) is a perspective view of a composite prepreg for a multilayer board.

FIG. 2 is a schematic view showing a material configuration of a six-layer plate for explaining an example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pin hole 2 Hole periphery 3 Heating iron tip 4 Composite prepreg 5 Copper foil 6 Inner plate

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ identification symbol FI H05K 3/46 H05K 3/46 G // B29K 105: 06 (58) Field surveyed (Int.Cl. ⁶ , DB name) B29B 7/00-17/02

Claims (2)

(57) [Claims] 1. A superimposed multiple prepregs, near edge
Composite prepreg formed by thermocompression bonding at multiple locations . 2. A composite prepreg formed by laminating a plurality of prepregs provided with holes for pin lamination with the positions of the holes aligned and thermocompression bonding the periphery of the holes.