Flexible system for real-time plasma decapsulation of copper wire bonded IC packages

Abstract

Improvements of the Microwave Induced Plasma system especially designed for decapsulation of copper wire bonded integrated circuit (IC) packages are described. The system integrates a programmable XYZ-stage and a Charge-Coupled Device (CCD) camera allowing computer controlled process and real-time imaging on the details of the IC package during plasma etching. Parameters that affect the etching profile are investigated. Decapsulation of a plastic small outline package SO32 with 38 um copper wire bonds is conducted by three consecutive etching cycles using plasma beam scanning. The scan route and speed in relation to the plasma recipe and the package structure are discussed in detail. Causes of potential damage on the die and the wire bonds due to plasma etching are explained. Measures to improve the etching uniformity and to avoid potential overetching and oxidization damage are addressed.