High Speed Fluorescent Inspection of Non-visible defects

Abstract

Abstract The semiconductor industry continues to drive down defectivity rates, especially as the liability to ship replacement parts for field failures is pushed back into the supply chain. As dimensions are driven down to finer pitch, there are a certain class of defects that are caused by organic residue. Inspection using white light for advanced packaging is well known. However, organic residue defects appear transparent to white light but can be the root cause of field reliability issues. Residue on top of a bump, as an example, could cause damage to the part when operating at high temperatures in the field. Up until now, such an inspection would have been performed either using a manual fluorescent microscope or not at all. A well understood capability gap in the industry, defects due to organic residue are present in copper pillar bump and wafer level chip scale packages – both fan-in and fan-out, as well as packages based on organic substrate. This paper presents data from high-speed fluorescent inspection that could address this problem in a unique way that was not possible up until now.