JPH011296A - Manufacturing method for metal cored laminates - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing metal cored laminates suitable for through-hole circuit board applications.

Conventional technology With the recent need for high-density packaging in the field of electronic equipment,
As an insulating substrate printing layer for printed circuits.

Metal-core laminates are attracting attention from the viewpoints of heat dissipation, electromagnetic shielding, dimensional stability of insulating substrates, and heat resistance of mounted elements, and through-hole laminates using metal-core laminates are particularly popular for the purpose of high-density wiring. Demand for circuit boards is increasing.

A method for manufacturing a through-hole circuit board using a metal cored laminate is to first stack metal foil on both sides of a metal plate via a prepreg, and then heat and pressure laminate molding. Holes for circuit continuity were punched or drilled on both sides of the resulting laminate with a metal core, and the hole walls were coated with resin to ensure the insulation of the metal core of the hole walls. rear,
A common method is through hole plating.

Problems to be Solved by the Invention However, in the manufacturing method described above, the insulation of the through-hole portion is maintained by the resin film formed by coating, so there may be poor insulation between the through-hole and the metal core due to pinholes in the coating resin film, or There is a risk that the coating resin may peel off due to thermal shock, etc., and the reliability is lower than that of a general-purpose through-hole circuit board using an ordinary laminate as an insulating substrate.

An object of the present invention is to solve the above-mentioned problems and provide a metal-core laminated board suitable for circuit boards with excellent through-hole reliability.

Means for Solving the Problems The present invention has been made to achieve the above object, and will be explained below with reference to the drawings.

First, as shown in FIG. 1, a pre-cured thermosetting resin insulating plate 2 and a metal plate 1 are stacked (a).

The insulating plate 2, which was simultaneously punched in the same shape, is pushed into the punched hole 7 of the metal plate l formed by the punching process (b). Next, the metal plate l into which the insulating plate 2' is inserted
Layer metal foil 4 on both sides of (C) with prepreg 3 interposed therebetween.
, which are integrated by lamination molding under heat and pressure (d).

Function: As shown in FIG. 2, in the metal cored laminate 8, holes 5 for through holes are formed by drilling or punching in the portion into which the insulating plate 2' is inserted.

Conductivity is achieved by plating 6 on both sides of the wall for circuit continuity, or by filling the through holes 5 with a conductive substance. The wall surface of the through-hole hole 5 already has insulation properties without any special treatment, and the reliability of the through-hole is extremely high.

In addition, in the process of stacking the insulating plate 2 on the metal plate 1 and punching it, it is possible to use a prepreg obtained by impregnating and drying a thermosetting resin into a sheet-like base material instead of the insulating plate. , is not preferred for the following reasons.

That is, a prepreg whose resin is in a B-stage cured state has low strength and the resin itself is brittle. Furthermore, since the adhesion of the resin to the base material is small, the resin easily cracks and falls off from the base material when subjected to processes that apply external forces such as impact and bending, such as punching. Furthermore, when it comes to cutting the substrate by punching, the resin cannot adequately support the substrate, making it very difficult to cut the substrate.

On the other hand, in the case of a pre-cured insulating plate as in the present invention, the strength of the resin is sufficiently high, and the direction of shear cracks in the insulating plate that occur during punching is the direction of the maximum fresh force, making punching possible.

Embodiment The metal plate l used in the present invention is one that imparts heat shielding properties and electromagnetic shielding properties to a single circuit board, and therefore,
The material of the metal is not particularly limited, but generally aluminum, iron, etc. are used.

The pre-hardened insulating plate 2 that is pushed into the punched hole 7 of the metal plate 1 is a laminate plate that is easy to punch out, such as a paper-based phenolic resin laminate.

Epoxy resin-based Funposite laminate (OEM-1 to 4)
1. Although it is possible to use a synthetic fiber-based composite laminate (SB-1>, a glass cloth-based epoxy resin or polyimide resin laminate).

Since the insulating plate 2 is related to the through-hole reliability of the product, it is an epoxy composite laminate (OEM-t~
4) Synthetic fiber base material composite laminate (BE-1)
It is preferable to use a material with excellent dimensional stability in the thickness direction, such as a glass cloth base epoxy resin or a polyimide resin laminate. Furthermore, the thickness of the above-mentioned insulating plate 2 is the same as that of the metal plate 1.
Even if it is thicker or thinner than the metal plate, it will cause unevenness in the metal foil on the surface of the laminate during lamination molding in the subsequent process.

Further, the metal foil used in the present invention is copper.

It is a foil of nickel chrome, etc.

An embodiment of the present invention will be described.

Example 1 First, an aluminum plate (1st thickness) and a glass cloth-based epoxy resin laminate (1+a thickness) were formed using a heavy metal sheet, and at the same time, the glass cloth-based epoxy resin laminate was punched out in the same shape. I pushed it into hole 7. Next, copper foil (0.018 mm thick) was placed on both surfaces of the aluminum plate into which the laminate was inserted, through one sheet of prepreg (0.1 tab thick) obtained by impregnating and drying a glass cloth base material with epoxy resin. were stacked and laminated under heat and pressure to produce an aluminum cored laminate with a thickness of 1.2 mm.

Through holes were formed in the glass cloth base epoxy resin laminate portion of the above aluminum cored laminate to produce an aluminum cored through hole circuit board.

Comparative Example 1 Copper foil (0,018 m thick) was layered on both surfaces of an aluminum plate (1 m + thickness) through one glass cloth base epoxy resin prepreg (0,1 ym thick), and this was heated and pressed. An aluminum cored laminate having a thickness of 1.2 wx was produced by lamination molding.

Holes for through holes were drilled in the above aluminum cored laminate, and in order to insulate between the holes and the aluminum core, the hole walls were coated with epoxy resin and after the resin was cured, through hole plating was applied to the hole walls. , a circuit board with an aluminum core was fabricated.

Comparative Example 2 10 sheets of glass cloth base epoxy resin prepreg (0,1 lll 11 thickness) were stacked on an aluminum plate (1 mm thick), and punching holes were formed in the aluminum plate as in Example 1 by punching, and at the same time the glass cloth was An attempt was made to punch out the base epoxy resin prepreg into the same shape and push it into the punched hole in the aluminum plate. However, the cutting of the glass cloth in the prepreg was insufficient, causing significant breakage and destruction of the prepreg, and it was not possible to insert the prepreg into the punched hole of the aluminum plate.

Comparative Example 3 A general-purpose through-hole circuit board in which through-holes were formed in a double-sided copper foil-covered (copper foil thickness: 0.018 fl) glass cloth base epoxy resin laminate (1.2 rm thickness), and an ordinary laminate was used as an insulating substrate. was created.

Table 1 summarizes the results of performance tests conducted on the Examples and Comparative Examples.

1st Table: Treatment = 260°C silicone oil 5 seconds → 20°C Triclean 20 seconds cycle test.

*2 Processing: 260’C solder float.

IC mounting test using tR3 practical pattern, temperature rise limit 2
0'C0 a4 Shielding performance test in electromagnetic wave frequency band LOKHz-IGHz.

Effects of the Invention As described above, the present invention provides punched holes in the metal plate by stacking a pre-cured insulating plate and a metal plate, and forming an insulating hole in the punched hole in the same shape during the punching process. Since the metal foil is integrated with the metal plate through the prepreg, the circuit board with through holes formed in the insulating plate part of the metal core laminate has better heat resistance, heat dissipation, and electromagnetic shielding than ordinary metals. It has the same performance as a cored through-hole circuit board and at the same time has the effect of greatly improving through-hole conduction reliability, and its industrial value is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part showing the manufacturing process of the present invention, FIG. FIG. 2 is a plan view of a main part showing a state in which punched holes are formed in an aluminum plate, which is a metal plate, in an example. 1 is a metal plate, 2.2' is an insulating plate, 3 is a prepreg, and 4 is a metal foil.

Claims (2)

[Claims] 1. A step of stacking a thermosetting resin insulating plate on a metal plate and punching it, and pushing the insulating plate punched into the same shape into the punched hole of the metal plate, and both sides of the metal plate into which the insulating plate has been pushed. A method for manufacturing a laminate with a metal core, which is characterized by passing through a process of overlapping a metal foil with a prepreg interposed therebetween, and then laminating and forming the layers to integrate them. 2. 2. The method for manufacturing a metal cored laminate according to claim 1, wherein the thermosetting resin insulating plate is a laminate obtained by laminating and molding prepreg obtained by impregnating glass cloth with a thermosetting resin and drying it.