The evolution of the organic insulated power module and technology of high thermal conductivity and high heat resistance of the key material, which is the Thermally Conductive Electrically Insulating Layer (TCIL), have been reported. TCIL is a polymer / ceramic composite material filled with thermally conductive filler of ceramics in thermosetting resin. Due to the evolution of TCIL and utilization of bonding function that is characteristic of thermosetting resin, the heat dissipation performances have been greatly improved and the downsizing and higher power density of organic insulated module were achieved. Innovations on high performance polymer materials are expected to further improve the performance of power modules in the future.