Abstract: A circuit package for housing semiconductor or other integrated circuit devices (“die”) includes a high-copper flange, one or more high-copper leads and a liquid crystal polymer frame molded to the flange and the leads. The flange includes a dovetail-shaped groove or other frame retention feature that mechanically interlocks with the molded frame. During molding, a portion of the frame forms a key that freezes in or around the frame retention feature. The leads include one or more lead retention features to mechanically interlock with the frame. During molding, a portion of the frame freezes in or adjacent these lead retention features. The frame includes compounds to prevent moisture infiltration and match its coefficient of thermal expansion (CTE) to the CTE of the leads and flange. The is frame is formulated to withstand die-attach temperatures. A lid is ultrasonically welded to the frame after a die is attached to the flange.

Abstract: A microcircuit package having a ductile layer between a copper flange and die attach. The ductile layer absorbs the stress between the flange and semiconductor device mounted on the flange, and can substantially reduce the stress applied to the semiconductor device. In addition, the package provides the combination of copper flange and polymeric dielectric with a TCE close to copper, which results in a low stress structure of improved reliability and conductivity.