In today’s supply chains based on complex division of labor qualification plans must be executed at various levels of semifinished products. This study shows how a supporting process, assumed to be uncritical in terms of the qualification scope for a bare silicon die, is responsible for qualification fails. Although such failures are not relevant for the quality of the final product careful and thorough analysis is required to invalidate such failure modes.

This study investigated the origin of detrimental high ohmic behavior of contacts by means of analytical electron microscopy. The root cause for the high resistivity could be identified as delamination of the contact bottom in the nanometer range. Based on the results, we were able to establish a method to identify thin oxide layers using analytical methods without being able to spatially resolve them in a combined focused ion beam instrument and scanning electron microscope.