Semiconductor device having a cured silicone coating with non uniformly dispersed filler

摘要

A semiconductor device in which the surface of the semiconductor element is coated with a cured silicone in which there is dispersed filler having an average particle diameter of 0.01 to 500 micrometers and a specific gravity of 0.01 to 0.95 characterized in that the concentration of said filler is higher in the layer of said cured material remote from the element than in the layer of said cured material adjoining the element. The method for fabricating such a device comprises coating the surface of a semiconductor element with a curable silicone composition in which there is dispersed a filler having an average particle diameter of 0.01 to 500 micrometers and a specific gravity of 0.01 to 0.95 and thereafter curing said composition after the elapse of sufficient time for the filler in the layer of the composition adjoining the element to migrate into the layer of said composition remote from the element.