JPH0682931B2 - Method for manufacturing electric laminate - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a multilayer electric laminate using a metal plate as a substrate.

[Prior art]

In an electric laminate using a metal plate as a substrate, a perforated metal plate is used as a substrate to form a through hole. That is, a through hole having a diameter larger than that of the through hole is provided at a position where the through hole is to be formed in the metal plate, and a plurality of metal plates are overlapped with each other via the prepreg to perform heat and pressure molding, thereby forming a prepreg. The impregnated resin is cured to laminate and bond the metal plates, and the resin impregnated in the prepreg is caused to flow into and fill each through hole of the metal plate to be cured. At this time, a circuit board on which circuits such as a single-sided printed wiring board, a double-sided printed wiring board, and a multilayer printed wiring board are stacked between the metal plates through a prepreg, and the multilayer circuit boards are laminated and bonded between the metal plates. Is done. Since the through hole is formed in the resin portion filled in the through hole of the metal plate, the resin in the through hole can form a through hole in which insulation with the metal plate is secured. is there. Further, the inner periphery of the through hole is plated to form a through hole plating layer. However, since the inner surface of the through hole formed by punching in the resin portion filled in the through hole of the metal plate is a resin surface, the adhesion to the through hole plating layer is poor, and therefore the through hole There is a problem that the through-hole plating layer may be peeled off from the resin surface on the inner periphery, and the reliability of the through-hole may be reduced. Therefore, by including a filler in the resin for preparing the prepreg, the filler is also mixed in the resin filled in the through holes of the metal plate, and the through hole is formed in this resin portion. The filler is exposed on the inner peripheral surface during the perforating process, and the inner peripheral surface of the through hole is roughened with the filler to improve the adhesion of the through hole plating layer. ing.

[Problems to be Solved by the Invention]

However, since the particle size of the filler particles varies, the moving speed of the filler varies according to the flow of resin during molding, and molding is performed in a state where the filler is not uniformly dispersed. Sometimes. And if the filler is not uniformly dispersed in this way, a portion with a large amount of the filler and a portion with a small amount of the filler occur, and since the amount of the resin is small in the portion with the large amount of the filler, when the heating stress is applied, Peeling is likely to occur at the interface with the resin, causing problems in the physical properties of the laminate. When this interface peeling occurs, the refractive index of that portion changes, which causes color unevenness. The present invention has been made in view of the above points, and an object of the present invention is to provide a method for producing an electric laminate without the risk of peeling between the filler and the resin and without causing color unevenness. Is.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the present invention prepares a prepreg 3 by impregnating a resin mixed with a filler and stacks a plurality of metal plates 2 provided with through holes 1 with the prepreg 3 interposed therebetween. The resin impregnated in the prepreg 3 is heated and pressure-molded to cure the resin so that each metal plate 2 is laminated and adhered, and the resin impregnated in the prepreg 3 is allowed to flow into each through hole 1 of the metal plate 2 to be cured, and the through hole is formed. In forming the through hole 5 in the resin 4 portion in 1 as a filler,
When the central particle size is less than 1μ, the maximum particle size is the central particle size plus 2μ or less, and when the central particle size is 1μ or more and less than 5μ, the maximum particle size is the central particle size plus 4μ or less If the diameter is 5μ or more and less than 10μ, the maximum particle size is the central particle size plus 7μ or less, and if the central particle size is 10μ or more, the maximum particle size is the central particle size plus 15μ or less. I did. The present invention will be described in detail below. Prepreg 3 is glass paper (glass non-woven fabric) or glass cloth (glass woven fabric)
It is prepared by impregnating a base material such as a thermosetting resin such as an epoxy resin and drying it, but the structure of glass paper is sparser than that of glass cloth,
Since the resin to be impregnated can be permeated and retained in a sufficient amount, it is preferable to prepare the prepreg 3 using glass paper as a base material. The resin with which the base material is impregnated contains an inorganic filler. As the filler, Al ₂ O ₃ , Al ₂ O ₃ · H ₂ O, Al ₂ O ₃ · 3H ₂ O, talc, Mg
Any material such as O, CaCO ₃ , Sb ₂ O ₃ , and Ab ₂ O ₅ can be used. The filler is formed as a powder or granular material in which the particle diameters vary, but in the present invention, the particle diameter is adjusted so that if the central particle diameter is less than 1 μ, the maximum particle diameter is the central particle diameter plus the central particle diameter. 2μ or less, the central particle size is 1μ or more 5
If it is less than μ, the maximum particle size is the central particle size plus 4μ or less. If the central particle size is 5μ or more and less than 10μ, the maximum particle size is the central particle size plus 7μ or less. If the diameter is 10μ or more, the maximum particle size will be the central particle size plus
Those of 15μ or less are used. Here, the central particle size means the median value (median) of the particle size distribution. Those that deviate from the distribution center of the particle size to the larger one have poor fluidity in the resin, so the range of particle size is set in this way, and the filler that follows the flow of the resin during molding is set. The flow rate can be made uniform, and the filler can be evenly distributed. The amount of the filler mixed is not particularly limited, but it is preferably set in the range of 30 to 150 PHR. In order to manufacture an electric laminate using the metal plate 2 as a substrate by using the prepreg 3 thus prepared by impregnating the resin containing the filler, the through holes 5 are first formed in the metal plate 2 such as a copper plate. The through hole 1 is formed by punching, drilling, or the like at a portion to be formed. The through hole 1 is formed with a diameter larger than that of the through hole 5. Then, as shown in FIG. 1A, several metal plates 2 are stacked with the prepreg 3 interposed therebetween, and metal foils 9 such as copper foil are further stacked on the top and bottom with the prepreg 3 interposed therebetween. At this time, a single-sided printed wiring board, a double-sided printed wiring board,
A circuit board 10 on which a circuit such as a multilayer printed wiring board is formed is stacked via a prepreg 3. Then, by heat-pressing this, the resin impregnated in the prepreg 3 is cured so that the metal plates 2 and the circuit board 10 are alternately laminated and adhered, and the metal foil 9 is laminated and adhered to the outermost layer. Each of the through holes 1 of the metal plate 2 is provided with a part of resin impregnated in
Then, the resin 4 is filled into the through hole 1 as shown in FIG. 1 (b). In this way, the metal plates 2 are laminated with the resin 4 filled in the through holes 1 of the metal plate 2 and the metal foils 9 are laminated on the upper and lower sides, respectively, and then drilled or punched. The through hole 5 is drilled as shown in FIG. The through hole 5 is formed with a diameter smaller than the diameter of the through hole 1 in the portion of the resin 4 filled in the through hole 1, and therefore the electrical insulation between the inner periphery of the through hole 5 and the metal plate 2 is achieved. Will be secured by the resin 4. Incidentally, in the above-mentioned embodiment, the through holes 5 are penetrated through a part of the metal plate 2 so as to be able to be grounded. After processing the through holes 5 as described above, through holes such as copper are plated on the inner circumference of the through holes 5 to form a through hole plating layer, and the metal foil 9 is etched to form a circuit. By doing things like
By using the metal plate 2 as a substrate, a multilayer inner layer circuit formed on the circuit board 10 and an outer layer circuit formed by processing the metal foil 9 are respectively provided to complete the electric laminated board. In the electric laminate thus formed, the resin is impregnated in the prepreg 3, and the filler is mixed in the resin. Therefore, the filler is also contained in the resin 4 filled in the through holes 1 of the metal plate 2. Therefore, when the through hole 5 is bored in the resin 4 portion, the filler is exposed at the inner periphery of the through hole 5 to form an uneven surface. Therefore, even if the inner peripheral surface of the through hole 5 is a resin surface, the adhesion of the through hole plating layer is enhanced by the anchor effect or the like.

【Example】

The present invention will be specifically described below with reference to examples. Examples 1-3, Comparative Examples 1-3 Terminal functional imide resin (TMS-20 manufactured by Sumitomo Chemical Co., Ltd.) 200 parts by weight, liquid epoxy resin 149 parts by weight, brominated novolac resin 136 parts by weight, Lewis acid compound 82 parts by weight. An epoxy-modified polyimide resin varnish was prepared by mixing 20 parts by weight of unsaturated bismaleimide, heating at 90 ° C. for 50 minutes, then cooling to room temperature and reacting for 30 minutes with stirring.
Al ₂ O ₃ · H ₂ O having the central particle size and re-large particle size shown in Table 1 is used as a filler in this epoxy-modified polyimide resin varnish.
The powder was blended at a blending amount of 50 PHR. Next, this epoxy resin-modified polyimide resin varnish was used as a substrate for glass paper (Japan Vilene EP-4075: 75 g /
780 g / m ² by dipping m ² ) and then drying
I made a prepreg. Here, the drying conditions were set so that the melt viscosity of the resin in the prepreg was 300 to 700 poise and the Glinis (resin flowability) was 20 to 25%. On the other hand, using a copper plate of 500 m × 400 mm × 0.5 mm as a metal plate,
Through holes with a diameter of 1.5 mm were provided in a number of 100 × 60 in width at a pitch of 1.8 mm. Then, three of these metal plates and two double-sided printed wiring boards formed by etching the copper foil of the double-sided copper-clad polyimide resin laminated plate to form a circuit are used as circuit boards, and these are shown in FIG. 1 (a). As shown in the above, the copper foils are alternately laminated through the prepreg and the copper foils are laminated on the upper and lower prepregs at 140 ° C while maintaining the pressure condition of 20 kg / cm ^2.
20 minutes at 170 ° C. and 90 minutes at 170 ° C. and cooling for 20 minutes to form a laminate, by which metal plates and circuit boards are alternately laminated to form a multilayer laminate with copper foil on the surface. Obtained. After that, a through hole having a diameter of 0.9 mm was drilled in the through hole portion of the metal plate in the multilayer laminated plate, and further copper plating was performed to perform through hole plating on the inner periphery of the through hole. With respect to the multilayer laminates obtained in Examples 1 to 3 and Comparative Examples 1 to 3, the presence or absence of color unevenness after heat treatment was measured. The results are shown in Table 1. As can be seen from the results in Table 1, color unevenness occurs in each of the examples in which the maximum particle size is set within the range specified by the present invention, and the interface between the resin and the filler due to heating stress. It is confirmed that peeling does not occur.

【The invention's effect】

As described above, in the present invention, as the filler to be mixed with the resin in order to enhance the adhesion of the through-hole plating layer,
When the central particle size is less than 1μ, the maximum particle size is the central particle size plus 2μ or less, and when the central particle size is 1μ or more and less than 5μ, the maximum particle size is the central particle size plus 4μ or less If the diameter is 5μ or more and less than 10μ, the maximum particle size is the central particle size plus 7μ or less, and if the central particle size is 10μ or more, the maximum particle size is the central particle size plus 15μ or less. As a result, there is no large variation in the fluidity of the filler according to the flow of resin during molding, the filler can be uniformly dispersed in the resin, and the interfacial separation between the filler and the resin due to uneven distribution of the filler. It is possible to prevent the occurrence of color irregularity by preventing the occurrence of

[Brief description of drawings]

1 (a), (b) and (c) are cross-sectional views showing respective steps of manufacturing an electric laminate. 1 is a through hole, 2 is a metal plate, 3 is a prepreg, 4 is resin in the through hole, and 5 is a through hole.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H05K 3/46 T 6921-4E

Claims (1)

[Claims] 1. A prepreg is prepared by impregnating a resin containing a filler, and a plurality of metal plates having through holes are stacked via the prepreg, and the prepreg is impregnated into the prepreg by heat-press molding. When the resin is cured and the metal plates are laminated and adhered, the resin impregnated in the prepreg is flowed into each through hole of the metal plate and cured to cure the through hole in the resin portion in the through hole. If the central particle size is less than 1μ, the maximum particle size is the central particle size plus 2μ or less, and if the central particle size is 1μ or more and less than 5μ, the maximum particle size is the central particle size plus 4μ or less. If the central particle size is 5μ or more and less than 10μ, the maximum particle size is the central particle size plus 7μ or less, and if the central particle size is 10μ or more, the maximum particle size is the central particle size plus 15μ or less. Special feature Method for producing electrical laminates to.