Pulse laser induced removal of mold flash on integrated circuit packages

Abstract

A dry process to remove mold flash on integrated circuit packages (IC packages) by using pulse, short wavelength laser irradiation. The mold remnants on the surface or in holes of the lead frame can be removed by pulse laser irradiation, with the effect of thermal expansion of lead frame metals and momentum transferring from the laser beam to the mold remnants. Compared with conventional water jet or etching processes, the new technique has high productivity and does not degrade the reliability of the IC packages, due to the fact that there is no water or chemical solutions involved in the process.