A process of making a multilayer lead frame assembly for an integrated circuit structure containing a planar metal member capable of serving as both a ground plane and a heat sink which comprises:
- a) bonding a planar metal lead frame to one surface of an insulating tape having a first b-stage adhesive curable at a first temperature on said one surface of said insulating tape by;
- i) placing said lead frame in contact with said first b-stage adhesive on said one surface of said insulating tape;
- and
- ii) heating said lead frame and said insulating tape to said first temperature to cure said first b-stage adhesive to bond said lead frame and said insulating tape together by said curing of said first b-stage adhesive;
- and
- b) bonding a planar metal member capable of serving as both a ground plane and a heat sink to a opposite surface of said insulating layer having a second b-stage adhesive thereon curable at a second temperature different than said first temperature by:
- i) placing said metal member in contact with said second b-stage adhesive on said opposite surface of said insulating tape;
- and
- ii) heating said metal member and said insulating layer to said second temperature to cure said second b-stage adhesive to bond said metal member and insulating tape together by said curing of said second b-stage adhesive.