| 摘要 |
PROBLEM TO BE SOLVED: To provide a resin composition suitable for use as an insulating adhesive layer in a metal-base circuit substrate, excellent in heat conductivity, and having high voltage resistance and adhesiveness. SOLUTION: This resin composition contains an epoxy resin, a curing agent, a curing promotor and an alumina powder. The alumina powder is contained 86-95 wt.% of the solid content of the resin composition and has the maximum particle diameter of not greater than 120μm, and contains not less than 90 wt.% of crystalline spherical alumina of which particle diameter distribution is that, average particle diameter D<SB>50</SB>=35-50μm, and the content satisfying [volume average particle diameter (MV)]/[number average particle diameter (MN)]=1.2-2.0 is 30-50 wt.%, that satisfying D<SB>50</SB>=5-15μm and [MV]/[MN]=2.30-3.5 is 30-50 wt.%, and that satisfying D<SB>50</SB>=0.1-2μm is 10-30 wt.%, and Na ion in boiled water extract is not higher than 20 ppm per solid content of the resin composition and the iron content detected by ICP emission spectral analysis is not higher than 100 ppm. COPYRIGHT: (C)2007,JPO&INPIT
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