An IR Microscopy Technique for Failure Analysis of Suspected Metallization Corrosion

The unequivocal indentification of metallization corrosion on humidity related failures has been a considerable problem. While fuming acid decapsulations are normally a reliable means of decapsulation without an attack on aluminum metallization, some question concerning possible aluminum attack during such precedures can be inevitable. Dry mechanical decapsulations are definative but not 100% effective and limit further electrical analysis. They are destructive to bonding if any further analysis is to be attempted in the absence of metal corrosion. A technique employing an infrared microscope has been successfully used to locate metal corrosion prior to exposing the active face of the bar and maintaining pin integrity for further analysis.