Optimization of Microwave Induced Plasma Etching Process for Decapsulation of Multi-Tier PCC Wire-Bonded Semiconductor Devices

Decapsulation of packaged integrated circuits is routinely conducted in failure analysis and reliability tests. In this work, we report on decapsulation of a complex packaged semiconductor device with multi-tier palladium-coated copper bond wires. Decapsulation process by oxygen-only Microwave Induced Plasma (MIP) was optimized with the goal to avoid corrosion of aluminium bond pads due to ultrasonic cleaning. In addition, we demonstrated a faster MIP process tailored specifically for exposure of large areas. In contrast to wet etching in acid, MIP ensures artifact-free decapsulation after which the wire bonds, bond pads and die were preserved in their original state, enabling further electrical tests and fault isolation to be performed on the devices. Two case studies are shown using MIP decapsulation and following fault isolation techniques to analyze Electrical Overstress (EOS) and metal bridging failures.