JPH0250829A - Manufacture of electric laminated board - Google Patents

Abstract

PURPOSE:To enable a lamination having no recess and protrusion in its surface to be carried out by integrating a prepreg in overlaying on one surface of a metallic plate provided with penetrating hole, and lamination-forming the composition of the metallic plate and the prepreg after a specific resin is filled into the penetrating holes, and performing then a punching work at the part of the resin. CONSTITUTION:Since the resin 4 containing a filling agent is filled previously into penetrating holes in a state of prepreg 3a overlaid on one surface of a metallic plate 2, recess and protrusion can be prevented from being produced, which tends to occur in the case wherein resin is flown into the penetrating holes 1 from the prepregs 3a, 3b during the period of molding, furthermore, by making the difference of a heat expansion between the metallic plate 2 and the resin 4 containing a filling agent to be 20ppm/ deg.C or below, the occurrence of recess and protrusion is prevented at the part of the metallic plate 2 and the resin 4 through the difference of a heat expansion. After the metallic plate 2 and a circuit plate 12 are laminated alternatively, and a metallic foil 13 is laminated on the surface, through holes 5 are worked by punching through drilling work and punching work. Through holes 5 are formed in the part of the resin 4 filled into the penetrating holes 1 in a smaller diameter than that of the penetrating holes 1.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for manufacturing a multilayer electrical laminate using a metal plate as a substrate.

[Conventional technology]

In an electrical laminate using a metal plate 2 as a substrate, a perforated metal plate 2 is used to form through holes 5. That is, as shown in FIG. 2(a), a through hole 1° 1... larger than the diameter of the through hole 5 is provided at the location where the through hole 5 is to be formed in the metal plate 2, and the plurality of through holes are formed. The prepreg 3 is formed by stacking the metal plates 2, 2... with the prepreg 3 interposed therebetween and performing heating and pressure forming.
The resin impregnated in the prepreg 3 is cured and the metal plates 2, 2, . At this time, between each metal plate 2 is a circuit board 12 such as a single-sided printed wiring board, a double-sided printed wiring board, or a multilayer printed wiring board.
12... and a metal such as copper foil on the outermost layer?
113 is overlapped and molded, as shown in Figure 2 (b).
), connect the circuit board 12.12... to each metal plate 2.2.
... and laminated in between, and metal M13 is laminated on the outermost layer. Then, by drilling a through hole 5 as shown in FIG. 2(c) in the part of the resin 14 that has filled the through hole 1, a through hole is formed in which the resin 14 ensures insulation from the metal plate 2. - 5 can be formed. Thereafter, by etching the metal foil 13 to form a circuit and plating the through holes 5, the multilayer metal plate 2 is used as a base, and the circuit boards 1, 2, 12, etc. are formed. Inner layer circuit and metal foil 1
It is possible to finish a multilayer electrical laminate in which a multilayer circuit is formed with the outer layer circuit according to No. 3.

[Problem to be solved by the invention]

However, when manufacturing an electrical laminate by molding in the process shown in FIG. The resin in the part corresponding to through hole 1 is through hole 1.
As a result, as shown in FIG. 3, in the outermost layer of prepreg 3, a hollow is created at the part of the through hole 1 where the amount of resin is reduced. 15 is formed, and this dent 15 is also formed on the metal foil 13.
This will cause unevenness on the surface. Especially resin 14
Since there is a large difference in coefficient of thermal expansion between the metal plate 2 and the resin 14 in the through hole 2 during the cooling process after laminated molding, the depression 15 becomes larger.
Large irregularities will also occur. If the metal foil 6 has such irregularities, it becomes impossible to apply the etching lens accurately, which causes problems such as making it difficult to form a circuit. The present invention has been made in view of the above points, and it is an object of the present invention to provide a method for manufacturing an electrical laminate that can be laminated without causing unevenness on the surface.

[Means to solve the problem]

In order to solve the above problems, the method for manufacturing an electrical laminate according to the present invention is to close the opening on one side of the through hole 1 by overlapping and integrating the prepreg 3a on one side of the metal plate 2 provided with the through hole 1. , the difference in thermal expansion coefficient with metal plate 2 is 20 ppm/
After filling the through hole 1 with a filler-containing resin 4 of C or less, a plurality of composites 6 of this metal plate 1 and prepreg 3a are stacked with another prepreg 31 interposed therebetween, and this is heated and pressurized. It is characterized in that it is laminated and molded, and then a =4 through hole 5 is punched in the portion of the filler-containing resin 4 in the through hole 1.

[Effect 1] In order to fill the through hole 1 with filler-containing resin 4 in advance with the prepreg 3a stacked on one side of the metal plate 2, prepregs 3a and 3b are poured into the through hole 1 during molding. It is possible to prevent unevenness from occurring when resin is introduced, and furthermore, by setting the difference in thermal expansion coefficient between the metal plate 2 and the resin 4 containing the filler to 20 ppm/°C or less,
It is possible to prevent unevenness from occurring between the metal plate 2 and the resin 4 due to the difference in coefficient of thermal expansion. The present invention will be explained in detail below. The metal plate 2 is made of a copper plate, an aluminum plate, etc., and the portion where the through hole 5 is formed is shown in FIG.
As shown in , ), the through hole 1 is drilled. The through hole 1 is formed with a diameter larger than that of the through hole 5. After forming the through holes 1, it is preferable that the metal plate 2 is subjected to a surface treatment in order to improve its adhesion to the resin. As the surface treatment, blackening treatment or browning treatment using an oxidizing treatment liquid or the like, surface roughening treatment by electrolytic plating, etc. can be employed. Next, a prepreg 3a is stacked on one side (lower side) of this metal plate 2 and integrated as shown in FIG. 1(b). Integration is prepreg 3a on metal plate 2
This can be done by stacking them and then layering release paper or the like on top and bottom, and then heating and press-molding them in this state, or applying heat and thermo-compression bonding. The prepreg 3a is prepared by impregnating a base material such as glass cloth or paper with a thermosetting resin such as epoxy resin or polyimide and drying it. Since it only acts to close the opening at the bottom of 1, a thin material with a thickness of about 1. Next, the resin 4 mixed with a filler is poured into the through hole 1 of the metal plate 2 and filled as shown in FIG. 1(c).The resin 4 containing the filler is not particularly limited. However, it is preferable to use the same type of resin as the resin impregnated into the prepreg 3a, such as epoxy resin or polyimide.Furthermore, as the filler, Al2O3, Al2O3・H
20, A 1203・3H20, Talc, M I? OS
Spherical powders such as CaCO3, 5b203, Ab20s, E7y lath, D77' lath, T〃Glass R〃Glass Q
Examples include acicular powder obtained by finely cutting and grinding lath M&fiber such as glass, aramid fibers such as Kevlar (manufactured by DuPont), and Chiku/-La (manufactured by Ontaisha). In the present invention, the coefficient of thermal expansion of the filler-containing resin 4 (
In other words, the coefficient of thermal expansion of the filler-containing resin 4 is adjusted so that the difference in coefficient of thermal expansion (after the resin is cured) from that of the metal plate 2 is 20 ppm/'C or less. If the coefficient of thermal expansion is αh, αM 20 ppm/ ”C≦a6≦αM + 2
The type and amount of the filler added to the filler-containing resin 4 are adjusted and set so that it becomes 0 ppm/'C. In order to fill the through hole 1 with the filler-containing resin 4, the resin 4 containing the filler may be prepared in a liquid state such as varnish and poured, or may be prepared in a powder form and poured.
This can be done by forming the through hole 1 in advance and fitting it in a solid state. Then, the resin in the through hole 1 is cured by heating while depressurizing and degassing as necessary. Next, the metal plate 1 with the resin 4 filled in the through hole 1 as described above.
In manufacturing an electrical laminate using a composite body 6 formed by laminating a prepreg 3a and a prepreg 3a, the method shown in FIG.
), several sheets of composite 6 are stacked via prepreg 31), and prepreg 313 is placed on the outer surface of the outermost layer of composite 6.
A metal foil 13 such as copper foil is layered on top of the metal foil 13 via the metal foil 13. At this time, circuit boards 12, 12, . . . on which internal layer circuits such as a single-sided printed wiring board, a double-sided printed wiring board, and a multilayer printed wiring board are formed are set in each composite body 6 via the prepreg 3b. As with the prepreg 3a, this prepreg 3b is prepared by using glass cloth or paper as a base material, impregnating it with a thermosetting resin such as epoxy resin or polyimide, and drying it. As this resin, it is preferable to use the same kind of resin as the resin used for preparing the prepreg 3a. Further, there is no need to add a filler to the resin used to prepare this prepreg 3b. Then, by performing heat and pressure molding, the resin impregnated into the prepreg 3b is cured, and each composite body 6 and the circuit board 12 are laminated and bonded alternately, resulting in a layered structure similar to that shown in FIG. 2(b). An electrical laminate can be obtained in which metal plates 2 and circuit boards 10 are alternately laminated and metal foil 13 is laminated and bonded to the outermost layer. At this time, since the resin 4 is filled in the through holes 1 of the metal plate 2 in advance, the resin impregnated into the prepreg 3b is absorbed into the through holes 1.
Therefore, there is no fear that the outermost layer prepreg 3b will be dented in the portion corresponding to the through hole 1, and the metal ? There is no fear that unevenness will occur on the surface of 113. However, metal plate 2
Because the difference between the coefficient of thermal expansion of the resin 4 filled in the through hole 1 and the coefficient of thermal expansion of the filled resin 4 filled in the through hole 1 is as small as 20 ppm/''C, the metal plate 2 and the resin 4 contract during cooling after laminated molding. The difference in the degree of thermal expansion is small, and there is no fear that a dent will occur in the resin 40 portion of the through hole 1 due to a difference in thermal expansion coefficient. If the difference in coefficient is larger than 201) concave/'C, there is a risk that a depression will occur due to the difference in coefficient of thermal expansion. After laminating the metal foil 13 on the surface, a through-hole 5 is formed by drilling or punching.The through-hole 5 is formed by using the resin 4 filled in the through-hole 1 as shown in FIG. 2(c). The diameter of the through hole 5 is smaller than that of the through hole 1, and therefore, the resin 4 ensures electrical insulation between the inner periphery of the through hole 5 and the metal plate 2. , some of the through-holes 5 are formed to penetrate the metal plate 2 for grounding, etc. After processing the through-holes 5, the inner periphery of the through-holes 5 is plated with copper or the like. A multi-layered circuit is formed by forming hole plating or etching the metal foil 13 to form an outer layer circuit, so that the multilayer metal plate 2 is used as a base, and an inner layer circuit formed by the circuit board 12 and an outer layer circuit formed by the metal foil 13 are provided. It is finished as an electrical laminate.In this product, the resin 4 filled in the through hole 1 of the metal plate 2
contains a filler, so when the through hole 5 is processed, the filler is exposed on the inner circumferential surface of the through hole 5 and the inner circumferential surface of the through hole 5 becomes an uneven surface, resulting in an anchor effect of the uneven surface. This increases the adhesion of through-hole plating applied to the inner peripheral surface of through-hole 5. [Examples] Next, the present invention will be specifically explained using examples. 1.2, 1-3 Terminal functional imide resin (TMS20 manufactured by Sumima Kagaku Co., Ltd.) 20
0 parts by weight, liquid epoxy resin 149 parts by weight, bromination 7
Epoxy-modified polyimide was produced by mixing 136 parts by weight of Borac resin, 82 parts by weight of Lewis acid compound, and 20 parts by weight of unsaturated bismaleimide, heating at 90°C for 50 minutes, cooling to room temperature, and reacting with stirring for 30 minutes. A resin varnish was prepared. Next, a prepreg of 780 g/+n2 was prepared by dipping glass paper (EP-4075 manufactured by Nippon Vilene Co., Ltd., Nippon Vilene 5 g/m2) as a base material into this epoxy-modified polyimide resin varnish and then drying it. The conditions are that the melt viscosity of the resin in the prepreg at 130°C is 300-700 voids, and
The Glynis (resin flowability) under the conditions of 70°C and 20 kg/c++2.10 minutes was set to be 20 to 25%. On the other hand, as a metal plate 500+n+nX400m+nX0
Using a 05mm copper plate, make a through hole with a diameter of 1.5 mm.
The number of pieces was set at 8111111 pitch, 100 vertically by 60 horizontally. Then, overlap the above prepreg on the bottom surface of this metal plate and
The prepreg is pasted on the lower surface of the metal plate by heating it to 50°C, and in this state, a filler-containing resin prepared by blending E glass fine powder as a filler with the epoxy-modified polyimide resin varnish is poured and filled. did. E-glass fine powder has an average length of 35μ and an average diameter of 13
μ was used and mixed in the amounts shown in Table 1. Then, three composites of this metal plate and prepreg were used, and two double-sided printed wiring boards were formed by etching the copper foil of a double-sided copper-clad polyimide resin laminate to form a circuit. As shown in (d), the above prepregs are alternately stacked, and 35μ thick copper foils are stacked on top and bottom via the prepregs, and first, a pressurizing condition of 20kg/cm2 is maintained at 140°C for 20 minutes at 170°C. By heating at ℃ for 90 minutes and cooling for 20 minutes to perform lamination molding, a multilayer laminate was obtained in which metal plates and double-sided printed wiring boards were alternately laminated and copper foil was spread on the surface. After this, a through hole with a diameter of 0.9 mm was drilled in the multilayer laminate at the through hole part of the metal plate.
Next, copper plating was performed, and through-hole plating was applied to the inner periphery of the through-hole. The unevenness of the surface of the electrical laminate thus obtained was measured. The maximum values of unevenness are shown in Table 1. In addition, the coefficient of thermal expansion αR of the resin containing the filler (unit: ppm/'C=X10-'/
"C) is shown in Table 1. Furthermore, the coefficient of thermal expansion α of the copper metal plate
ゎ is 17 ppm/''C, and the difference between the coefficient of thermal expansion of the filled resin and the coefficient of thermal expansion of the metal plate is as shown in Examples 1 and 2 of Table 1. The difference between the coefficient of thermal expansion and the coefficient of thermal expansion of the filled resin is 20 p.
It is confirmed that by setting the temperature to pm/'C or less, the occurrence of unevenness becomes so small that it hardly becomes a problem.

【Effect of the invention】

As described above, in the present invention, prepreg is stacked and integrated on one side of a metal plate provided with a through hole to close one side of the through hole, and this through hole is filled with resin containing a filler. After that, we layered multiple composites of metal plates and prepregs with other prepregs interposed between them, and then layered them by heating and pressurizing them, so that we could mold them with resin filling the holes in the metal plates. The resin impregnated into the prepreg will not flow into the through holes, and the outermost layer of prepreg will be dented in the area corresponding to the through holes, causing unevenness on the surface. This is something that can be prevented. In addition, we used a resin with a thermal expansion coefficient of 20 ppm/'C or less to fill the through holes in the metal plate, so that the difference between the coefficient of thermal expansion of the metal plate and the through hole is 20 ppm/'C or less. The difference in the degree of shrinkage between the resin and the resin filled in the hole is small, and there is no fear that depressions will occur in the resin portion of the through hole and unevenness will occur due to the difference in coefficient of thermal expansion.

[Brief explanation of the drawing]

Figures 1 (a) to (d) are cross-sectional views showing each process of manufacturing an electric laminate, Figures 2 (a), (b), and (c) are cross-sectional views of a conventional example, and Figure 3 is a cross-sectional view of the conventional example. It is an enlarged view of part A in (b). 1 is a through hole, 2 is a metal plate, 3 a and 3 b are prepregs, 4 is a resin containing a filler, 5 is a through hole, and 6 is a composite.

Claims (1)

[Claims] (1) By stacking prepreg on one side of a metal plate with a through hole and integrating it, the opening on one side of the through hole is closed, and the filled resin has a coefficient of thermal expansion difference of 20 ppm/℃ or less with the metal plate. After filling the through holes, multiple sheets of this metal plate and prepreg composite are stacked with other prepregs interposed between them, and this is laminated by heating and pressurizing, and then the filled resin in the through holes is A method for producing an electrical laminate, characterized by punching through holes in some parts.