JP2581238B2 - Manufacturing method of metal-clad laminate - Google Patents

Description

The present invention relates to a method for producing a metal-clad laminate to which an electrical reliability test can be applied.

[Conventional technology]

With the recent increase in density and miniaturization of printed wiring boards or multilayer printing, metal clad laminates used need to have high electrical reliability with respect to insulation. As shown in FIG. 4, the method for confirming the electrical reliability is such that the upper and lower metal foils 1 of the laminated plate test piece are in contact with both poles 6 of the test apparatus 5, and the withstand voltage of the laminated prepreg layer 2 and Measure the insulation resistance. This method is regarded as important for confirming the electrical reliability of a printed wiring board or a multilayer printed wiring board before circuit processing.

[Problems to be solved by the invention]

In the production of a laminate, the size of the metal foil is increased by about 5 to 150 mm from the end of the prepreg because the resin flows out from the prepreg to the periphery in the heating and pressurizing step and soils the equipment. As a result, the resin does not flow to the outside, but places where the upper and lower metal foil edges come into contact with each other are generated, and in this state, the withstand voltage test cannot be performed. That is, a test is performed by cutting off the peripheral end portion after the heat and pressure molding as shown in FIG.
This method can be used if the thickness between the upper and lower metal foils is normal,
In particular, when the thickness is thin, as shown in FIG. 6, the chips 7 of the metal foil generated at the time of cutting remain on the cut surface and the current is applied, resulting in that the electrical reliability cannot be confirmed. This tendency becomes stronger as the resin-impregnated base material (prepreg) of the laminate is thinner,
Recently, metal-clad laminates having a thin base layer of 50 to 100 μm have appeared, and there is no method for confirming electrical reliability.

An object of the present invention is to provide a method for manufacturing a metal-clad laminate, to which an electrical reliability test can be applied even when having a thin resin-impregnated base material layer (prepreg).

[Means for solving the problem]

The present invention is a method for producing a metal-clad laminate in which a metal foil is superimposed on both surfaces of a prepreg and heated and pressed to form a metal plate and a metal plate having a four-sided end that is 5 to 150 mm longer than the prepreg on one surface of the prepreg. This is a method for producing a metal-clad laminate, in which a metal foil whose four sides are shorter by 5 to 50 mm than the prepreg on the opposite surface, and a releasable sheet and a mirror plate of the same size as the mirror plate are further stacked and heated and pressed. .

The present invention will be described with reference to FIG. On one side of the prepreg 2, a metal foil 1 whose four side edges are longer than the prepreg 2 and a mirror plate 4 of the same size are stacked, and on the other side, a metal foil 1 whose four side edges are shorter than the prepreg 2 and a release sheet 3 of the same size as the mirror plate. And the end plate 4 are stacked.

The thickness of the release sheet 3 is not particularly limited, but is preferably thinner than the prepreg 2. Its size is larger than the prepreg 2 from the end by about 5 to 150 mm.

The size of the end plate 4 is also the same as that of the release sheet. In the production of a laminated plate, the above-mentioned constituent materials and end plates are superimposed as shown in FIG. 1 and are heated and pressed between hot press plates.
The laminated plate obtained by removing the end plate and the release sheet is subjected to a withstand voltage test and an insulation resistance test as shown in FIG. After the test is completed, the terminal is cut as shown in FIG. 3 to obtain a product of an appropriate size.

[Action]

According to the production method of the present invention, the resin flowing out of the prepreg is located between the metal foil and the release sheet and does not flow out to the outside and does not pollute the production equipment.

In addition, in the state of the withstand voltage test shown in FIG. 2, since there is a resin layer between the upper and lower metal foils and the distance between the exposed portions at the ends of the upper and lower metal foils is long, no short circuit is caused. Can be tested.

〔Example〕

As the prepreg 2 shown in FIG. 1, a glass cloth impregnated with a thermosetting epoxy resin, dried, and cut to a thickness of 70 μm and 1000 mm square was used. End plate 4 is 10 on both sides
60 mm square, 1060 mm metal foil on the opposite side of the release sheet 3
960 mm square metal foil in contact with the release sheet,
The thickness of each metal foil was 35 μm. In the release sheet 3,
A 1060 mm square tetra film having a thickness of 20 μm was used.

As shown in FIG. 1, the above-mentioned materials were stacked and heated and pressed under a head plate to obtain 100 copper-clad laminates. The resulting laminate was subjected to a withstand voltage test at DC 500 V as shown in FIG.
99 out of 100 passed. One of the rejects was due to a metal piece mixed in the base material, and the effect of the present invention was 100%.

(Comparative example) Copper foil above and below the prepreg is 35μm1060m thick
m square. Without using a release sheet, the same prepreg was used as in the example, and the same processing as in the other examples was performed to obtain 100 copper-clad laminates.

The obtained laminate was subjected to a withstand voltage test in the same manner as in the example, and 100
It was recognized that all the sheets were in a conductive state between the ends of the upper and lower copper foils. As a result of examining the total number, it was found that there was only one sheet in which a metal piece was mixed into the base material and caused conduction.

〔The invention's effect〕

When the results of the example of the present invention and the comparative example are compared, the effect can be clearly recognized. According to the production method of the present invention, especially when the prepreg layer is thin, a withstand voltage test immediately after molding can be accurately performed. On the contrary, it is impossible to obtain accurate test results by the conventional method.

[Brief description of the drawings]

FIG. 1 is an explanatory view of the structure of the present invention, FIG. 2 is a state diagram of a withstand voltage test, FIG. 3 is a product drawing of the laminated plate of the present invention, FIG. 4 is a conventional withstand voltage test, and FIG. Sample drawing for withstand voltage test, 6th
The figure is a conventional test state diagram. DESCRIPTION OF SYMBOLS 1 ... Metal foil, 2 ... Pre-preg, 3 ... Releasable sheet, 4 ... End plate, 5 ... Test device, 6 ... Electrode, 7 ...
Chips of metal foil.

Claims (1)

(57) [Claims] (1) In the production of a metal-clad laminate in which a metal foil is laminated on both surfaces of a prepreg and heated and pressed, a metal foil and an end plate of the same size having a four-sided edge longer than that of the prepreg by 5 to 150 mm are formed on one surface of the prepreg. A metal-clad laminate characterized in that a metal foil having a four-sided end shorter than that of the prepreg by 5 to 50 mm on the opposite surface and a releasable sheet and a mirror plate of the same size as the mirror plate are further stacked and heated and pressed. Production method.