Early screening method of chip-package interaction for multi-layer Cu/low-k structure using high load indentation test

Abstract

We have developed High Load Indentation (HiLI) test as a novel early screening method of Chip-Package Interaction (CPI) for multi-layer Cu/Low-k interconnects structure with bumps. In this study, by using HiLI test, we evaluated a lower fracture toughness SiCOH (Low-k), a thicker under bump metallization (UBM) and a plasma-damaged polyimide (PI) around these bumps, whose white bump failures relatively tend to occur compared to the standard structure. We found that both these in-situ load profiles and observations after the test corresponded with these white bump failures. In addition, we compared between a polished bump structure and an un-polished bump one by the test.