Development of the green plastic encapsulation for high density wirebonded leaded packages

Abstract

The push in the electronics industry toward miniaturization and high density wirebonds is a major driving force in integrated circuit (IC) package design. One problem has been the use of conventional mold compounds to encapsulate the high density wirebonded packages, due to performance issues, such as wire sweep and coplanarity. Additionally, in order to match lead-free solutions in the near future, antimony- and halogen-free molding compound must be developed because antimony (Sb) and halogens in current flame retardant systems pose environmental hazardous. This article, discusses a “green” compound that eliminated these environmentally hazardous elements, resolving moldability and reliability issues for high density wirebonded packages. The reliability assessment was conducted at the maximum reflow peak temperature of 240 °C after moisture soaking at 60 °C/60%RH for 40 h, followed by temperature cycle tests. The study aimed for good package integrity, process, and performance to meet the requirements of high volume production and an acceptable moisture sensitivity (level 3) with a reflow temperature of 240 °C. The study indicates that moldability and reliability involved separate issues and offers a solution for high volume production and field application.