LOW MECHANICAL STRESS LEADFRAME
Original Publication Date: 1985-Oct-01
Included in the Prior Art Database: 2001-Oct-16
Transfer molding of thermosetting epoxy compounds is a commonly used method to encapsulate integrated circuit devices which have been attached and connected to a dual-in-line multiple lead metal frame, thereby pro- viding mechanical protection and electrical insulation among separate components within the packages unit. Dur- ing the high temperature molding process, chemical curing of the epoxy compound and thermal contraction differences between the molded plastic body and the metal leadframe result in residual compressive stresses within the metal structure which are greater than the critical load required to cause buckling in the delicate leadframe members, An improved leadframe is described which substantially provides control of the residual metal stresses for dimensional stability of the critical structural members.