| 摘要 |
PROBLEM TO BE SOLVED: To suppress warp significantly in producing a printed wiring board of cavity structure or multilayer structure by setting the glass transition point of an insulating board lower by a specified temperature than that of the insulat ing board when the thermosetting resin composing the insulating board is cured completely. SOLUTION: A sheet-like fibrous basic material is impregnated with a thermosetting resin and dried to form a prepreg layer which is then hot pressed to produce an insulating board. Glass transition point of the insulating board is set lower by 20 deg.C or more than that of the insulating board when a thermosetting resin composing the insulating board, e.g. epoxy resin, phenol resin, cyanate resin, polyimide resin or unsaturated resin, is cured completely. A metal foil or a printed wiring board is then pasted integrally to one side of the insulating board through an adhesive layer by hot press. According to the method, warp can be suppressed significantly at the time of producing a printed wiring board of cavity structure or multilayer structure. |
