ALX permanent polymer dielectrics for microelectronic packaging applications

In this paper we present the results of a study done to compare the new Asahi Glass ALX polymers with other microelectronic polymers in typical WLP structures. We present property data on ALX-211, including spin speed curves and resolution plots, planarization, thermal stability and stress data and adhesion as evaluated using polymer bump shear testing. We have examined the processing of ALX-211 and developed a standard process flow for these materials. We have used ALX-211 in a typical bump-on-polymer process flow, with eutectic Sn/Pb solder bumps, and compared its performance to that of BCB through solder bump shear testing.