Study of reliability and process ability for preset underfill sheet material as future standard flip chip packaging process

Process technology in flip chip assembly is an important factor in considering the package reliability, cost reduction and stability of mass production. A novel flip chip packaging technology using non-conductive underfill resin sheet was developed. This new technology is no-flux flip chip packaging technology which eliminates the flux applying and cleaning process in current liquid underfill resin with dispensing system. It has a lot of potential to make the packaging process simpler and reduce handling difficulty compared with liquid underfill dispensing process. Additionally, it makes moisture related reliability performance higher because this underfill resin sheet introduces an epoxy resin with phenol curing system. In this paper, we studied the process ability and reliability on two kinds of packaging processes with non-conductive underfill resin sheets. The higher stress reliability and productivity was shown with the proper underfill resin component and packaging process.