PEDESTAL ENCAPSULATION CURE FOR TAB ASSEMBLIES
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2002-Jan-02
A process for encapsulation cure overcomes problems encountered when TAB tin plated leadframes are heated. The encapsulation cure process is performed on TAB units after the die has been bonded to the tape (inner lead bonding-ILB); and consists of baking the parts in an oven for a specified time(s)/temper- ature(s). The primary problem is that the curing process consumes the free tin in a copper/tin intermetallic, which greatly reduces the solderability of the part for future outer lead bonding (OLB) by the customer. This problem cannot be addressed by the addition of tin before the curing process due to negative effects on the ILB process, and the potential for "whisker" formation.