Microdot Epoxy Stamping Process Qualification for Substrate-Based Optocoupler BGA Packaging

Abstract

Optocoupler is a semiconductor device that allows signal to be transferred between circuits, while keeping the circuits electrically isolated from each other. The demand of surface mount Optocoupler packaging has progressed from a conventional Dual-in-line packaging (DIP) to Small outline packaging (SOP) to miniflat packaging (MFP) and to Ball Grid Array Packaging (BGA) for Optocoupler. This innovative design employs the use of premolded lead frame technology offering thinner and smaller package structure. The need to maintain a consistent interconnect dispense material at die attach is very critical to attain a reliable adhesion of the epoxy to the die and to the substrate. Stamping or pin transfer approach was qualified as a die attach dispense system. This paper outlines the overall characterization work in the die attach process to meet the packaging requirement of the substrate based Optocoupler in a BGA package.