SEMICONDUCTOR DEVICE

PURPOSE:To make it possible to maintain high reliability without decreasing adhesion between an element and a lead frame at a high temperature in a high humidity atmosphere, by bonding a semiconductor element to the taps of the lead frame through silicone rubber. CONSTITUTION:Silicone prepolymer is hardened and bonded. In order to harden the silicone prepolymer, the vinyl group at the end of siloxane prepolymer is heated in the presence of organic peroxide so as to yied radical and polymerized. Silicone rubber of this type does not include solvent, and by products are not yielded. Since adhesion is weak when it is used as a single material, however, 1-5wt.% of silicon monomer having a hydroxide group at the end, or silicone coupling agent, is added. When the hardness of the rubber is soft, poor appearance tends to occur. Therefore, it is necessary to use the rubber, whose hardness is 2JIS-A or higher. When the rubber is too hard, disconnection failure is liable to occur. Therefore, the upper limit is made to be 40JIS-A (both at 25 deg.C).