Deep Dive into Systemic Secondary EOS Damage caused by a Process-Related Issue

Electrical Overstress (EOS) is a widely known problem in the semiconductor industry. Oftentimes, EOS damage occurs on a systemic manner at a certain location of the die. In this paper, multi-channel data-acquisition devices were returned for analysis to solve repetitive EOS symptoms of failure. We present two (2) case studies of the customer-returned devices that show anomalous passivation layer resulting in secondary EOS damages at Metal 2. This leads to an in-depth analysis of the EOS phenomena that we traced back at the wafer-level where process and electrical root cause were determined.