Extensive study of methods to screen print an encapsulant on bare die for multichip modules (MCM) and chip-on-board (COB), TAB, and flip-chip applications has produced a "printing encapsulation system" (PES). The key to this system was in the development of a liquid epoxy resin with optimum properties for printing encapsulation. We have developed a printing encapsulation system (PES) that produces high reliability and high quality encapsulated components, free of voids and demonstrating optimal thin consistent encapsulated shapes for advanced COB applications. The PES utilizes an epoxy resin we created with viscosity and open lid storage properties appropriate for mass production. The thixotropic properties have been adjusted carefully to allow for consistent high volume results. The system yields a void free encapsulated device that a is resistant to thermal shock and moisture after short cure times. Full curing can be achieved in as short as 15 min, lending this material and process easily to in-line manufacturing. >
