Thermoconductive composition, heat dissipating plate, heat dissipating substrate and circuit module using thermoconductive composition, and process for production of thermoconductive composition

A process for producing a thermally conductive composition, comprising:

• (A) preparing a mixture of a main agent containing a crystalline epoxy resin component which is not yet cured, a curing agent, and an inorganic filler;
• and
• (B) heating the mixture to not lower than the crystallization temperature of the crystalline epoxy resin component, and curing the main agent to form a cured thermosetting resin,
• wherein the content by percentage of the inorganic filler is 66% or more by volume and 90% or less by volume, and
• in the step (B), a main portion in which the inorganic filler is mainly contained is formed, and a surface layer portion made mainly of the crystalline epoxy resin component to be continuous to the main portion is formed on the main portion.