A method and structure for attaching a lead frame to a heat sink are provided. In one embodiment, a layer of thermally conductive, electrically insulating epoxy is formed on a heat sink and the epoxy layer is fully cured. A thermoplastic adhesive layer is formed on the epoxy layer, and the heat...http://www.google.de/patents/US5691567?utm_source=gb-gplus-sharePatent US5691567 - Structure for attaching a lead frame to a heat spreader/heat slug structure 
