Characterization studies of non-stick on pad (NSOP) using AES, XPS and TOF-SIMS

In the wafer fabrication (fab) and assembly process, process underetch residue and material contamination on bondpads may cause NSOP (non-stick on pad) problem. In this paper, the root cause of 3 NSOP cases were discussed and identified by using Auger Electron Spectroscopy (AES), X-ray Photoelectron Spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) techniques. Our failure analysis results showed that the root causes were attributed to either wafer fabrication or assembly process such as Si underetch, Ni
₂
O
₃
contamination and tape (with PDMS) residue.