Sheet form heat-dissipating member

A sheet form heat-dissipating member to be provided between a heat-generating electronic component and a heat-dissipating component, wherein

• the sheet form member is non-flowable at room temperature and becomes flowable due to heat generated from the heat-generating electronic component during operation of the heat-generating electronic component or due to heat actively applied during arrangement of the heat-generating electronic component, whereby an interface between the heat-generating electronic component and the heat-dissipating component is filled with the sheet form member with substantially no voids,
• the sheet form heat-dissipating member containing a heat-softening thermally conductive composition comprising:
• (A) 100 parts by mass of a silicone resin having a melting point of 40 to 110° C.;
• (B) 500 to 1,850 parts by mass of silver powder;
• and
• (C) 1.0 to 20 parts by mass of an organohydrogenpolysiloxane,
• the component (A) includes an R1SiO3/2 unit (wherein R1 is a group selected from alkyl groups having 1 to 10 carbon atoms and aryl groups having 6 to 10 carbon atoms) and an R22SiO2/2 unit (wherein R2 is a group selected from alkyl groups having 1 to 10 carbon atoms, alkenyl groups having 2 to 10 carbon atoms, and aryl groups having 6 to 10 carbon atoms),
• the silver powder as the component (B) has an average particle diameter of 0.5 to 10 μm, and the heat softening thermally conductive composition comprises 30 to 60 volt of the silver powder as the component (B), and
• the organohydrogenpolysiloxane as the component (C) includes an organohydrogenpolysiloxane having two or more hydrosilyl groups in one molecule.