Application of Auger Electron Spectroscopy and X-Ray Photoelectron Spectroscopy Analysis in Failure Analysis of Wafer Fabrication

Abstract

In this study, field emission AES and small-area XPS techniques were used to analyze surface composition and depth profiles on discolored bondpads to identify possible root causes for nonstick failure. In wafer fabrication, the discolored bondpad problem was found in the fab process with hot Al alloy metallization, which had resulted in nonstick failure during the assembly bonding process. Analytical results indicated that discolored bondpads with nonstick failure might be due to TiN residue introduced during the bondpad opening etching process. The possible root cause of TiN residue on bondpads was then confirmed to be arisen from ARC (TiN) layer underetched during the bondpad opening etching process. The solution to eliminate TiN residue on bondpads was taken to increase the etch time at the bondpad opening fab process.