JPH051986A - Inspection method for dirt adhering to prepreg - Google Patents

Abstract

PURPOSE:To easily and accurately inspect dirt adhering to prepreg at the time of cutting. CONSTITUTION:An adhesive tape or adhesive sheet pasted to prepreg as an object for inspection is peeled, and the weight of dirt adhering to the tape or sheet is measured. Also, the area of dirt adhesion is measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting dust adhering to a prepreg.

[0002]

2. Description of the Related Art A copper clad laminate used as a substrate for a printed wiring board is manufactured by stacking a plurality of prepregs, laminating copper foil on one or both sides thereof, sandwiching them with a mirror plate, and heating and pressing. A multilayer copper-clad laminate is manufactured by prepregs on both sides of an inner layer printed wiring board, copper foils stacked on the outer sides of the prepreg, sandwiched by a mirror plate, and heated and pressed.

This prepreg is obtained by impregnating a long base material with a liquid thermosetting resin and then drying the resin to form a B-stage resin. Since the prepreg is cut into a predetermined size during use, dust (mainly resin powder or base material powder generated by cutting) is attached. If this dust is not removed, not only will the environment of the next laminating step be adversely affected, but also defects called dents will occur on the copper foil surface, causing defects in the product. In addition, it adheres to the end plate and requires a lot of trouble to remove it.

Therefore, after cutting the prepreg to a predetermined size, dust generated is brushed off or sucked with a vacuum cleaner. In the past, dust was removed uniformly without checking the dust adhesion state to the prepreg, so that wasteful work was performed or insufficient removal resulted in product defects. This is because there was no appropriate inspection method for dust adhesion.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for inspecting dust adhering to a prepreg easily and accurately.

[0006]

The present invention is characterized in that an adhesive tape or an adhesive sheet attached to a prepreg to be inspected is peeled off, and dust adhering to the adhesive tape or the adhesive sheet is inspected. ..

The adhesive tape or the adhesive sheet is cut into a predetermined size, and the weight is measured. Then, the prepreg is attached to a predetermined place on the surface or a cut surface, peeled off, and the weight thereof is measured again. From the measurement result, the per unit length or the attached weight is obtained. It is also possible to evaluate the dust adhesion area per unit area.

When the adhesive tape or the adhesive sheet is charged with static electricity, dust floating in the air is adsorbed, so that it is removed by using an electrostatic remover or the like. The force for pressing the pressure-sensitive adhesive tape or pressure-sensitive adhesive sheet is preferably kept as constant as possible, but is not particularly limited. The adhesive strength of the adhesive tape or the adhesive sheet is not particularly limited, but is preferably such that the resin of the prepreg base material is not peeled off. Further, since the amount of dust attached changes depending on the adhesive force, the adhesive force should be measured in advance using a reference plate or the like, and those having the same adhesive force should be used.

[0009]

[Example] A prepreg having a resin content of 52% was produced by using a varnish composed of an epoxy resin, a curing agent and a solvent on a glass woven fabric having a thickness of 0.1 mm and a basis weight of 100 g / m ² , and 400 mm x 40
Cut to 0 mm. Dust adhered after cutting was removed under different conditions. Then, cut the adhesive tape into 50 mm x 50 mm,
After removing static electricity from the adhesive tape with a static eliminator, weigh the weight with an electronic balance, and make 1 for each of the four cut sides of the prepreg.
The position was changed at 5 points per side, and the adhesive tape was applied with fingers. The weight of this adhesive tape was measured to determine the dust adhesion amount per 1 m of the cut portion. This evaluation was carried out for all cut prepregs, and those with and without dust were selected.
A copper foil having a thickness of 18 μm was stacked on both sides using eight dust-free prepregs, and the foil was sandwiched with a mirror plate and heated and pressed at 170 ° C. for 90 minutes to obtain a copper-clad laminate. As a result, no defective appearance due to dents or resin powder was found on the obtained copper-clad laminate.

Comparative Example A prepreg having a resin content of 52% was manufactured by using a glass woven fabric having a thickness of 0.1 mm and a basis weight of 100 g / m ² and a varnish consisting of an epoxy resin, a curing agent and a solvent, and 400%.
It was cut into mm × 400 mm. Dust attached after cutting was removed by a conventional method, and a copper clad laminate was manufactured under the same conditions as in Example 1 below. The resulting copper-clad laminate had a defective appearance rate of 15% due to dents or resin powder adhesion.

[0011]

According to the present invention, since the dust attached to the prepreg can be easily and accurately inspected, it is possible to accurately grasp the dust attachment state which differs depending on the material of the base material, the type of resin, the cutting conditions and the like. .. Therefore, since it is possible to determine an appropriate dust removal condition, it is possible to significantly reduce product dent defects and resin powder adhesion defects. Further, since the end plate is not dirty, the end plate can be easily cleaned.

Front page continuation (72) Inventor Yuichiro Otsuru 1500 Ogawa, Shimodate City, Ibaraki Prefecture Hitachi Chemical Co., Ltd. Shimodate Factory

Claims (1)

Claims: 1. Dust attached to a prepreg, characterized by peeling off an adhesive tape or an adhesive sheet attached to a prepreg to be inspected and inspecting the dust adhered to the adhesive tape or the adhesive sheet. Inspection method.