Plasma Etching for Failure Analysis of Integrated Circuit Packages

Abstract

Plastic integrated circuit packages with copper wire bonds are decapsulated by a Microwave Induced Plasma system. Improvements on microwave coupling of the system are achieved by frequency tuning and antenna modification. Plasmas with a mixture of O2 and CF4 showed a high etching rate around 2 mm3/min. The role of O2 and CF4 in etching molding compound is described. Plastic package with 38 um Cu bond wires and a 2 mm * 3.5 mm die inside is fully decapsulated in 20 minutes. Cu wires remain undamaged after decapsulation proving the efficiency of this method.