| 摘要 |
PROBLEM TO BE SOLVED: To provide a prepreg for producing an insulation layer adaptable to the mounting of a large-current/heat-generating part, and suitable for a print wiring board requiring heat radiation. SOLUTION: The prepreg 3 for hot pressure forming is obtained by allowing a sheet-shaped fiber base material 2 to hold a thermosetting resin containing an inorganic filler 1, and bringing the resultant product into a semicured state. The prepreg has many through holes 4 scattered so as to have≥300μm distance between centers of the through holes, and the inorganic filler consists of scale-shaped filler or consists essentially of the scale-shaped filler. Preferably, the through holes 4 scattered in the prepreg 3 have 100-500μm hole diameters, and scattered so that the distance between the centers of the through holes may be≤1,100μm. More preferably, the inorganic filler 1 is a scale-shaped boron nitride having≥50 W/m×K heat conductivity, and is contained so as to occupy 10-60 vol.% in the volume of the total of the solid component of the thermosetting resin and the inorganic filler 1. COPYRIGHT: (C)2007,JPO&INPIT
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