Reliability test failure analysis using advance FA techniques on Cu wire bonded devices

Recent years many technical papers had discussed a lot on copper wire boned devices reliability by conducting various reliability tests [1, 2]. The most common failure analysis methods used are cross section, SEM and FIB to study the IMC growth and acid decapsulation to remove the mold compound to inspect die surface [1]. Usually wire pull and ball shear test were used to evaluate the wire and ball bond quality [3]. All above mentioned ways are destructive to the IC chips. This is quite risky when the samples quantity is not much and after reliability test only a few samples fail and then resulting in destroy the failed samples while couldn´t find the exact failure location. In this paper, through case study four types of advanced FA techniques were demonstrated and very minimum damage to the chips were proved, i.e. 3D X-ray, Magnetic current imaging, IR-Obirch (Infrared Optical beam induced resistance change) and Decapsulation using laser + MIP (Microwave Induced Plasma) etching. The first three FA techniques are absolutely not destructive to the chips, the decapsulation using laser + MIP plasma etching is a safe way to remove the mold compound of the IC package while preserve all bonded wires, bond pads and die surface.