Fine Pitch Probing and Wirebonding and Reliability of Aluminum Capped Copper Bond Pads

摘要

The requirement for improved electrical performance and reduced silicon area has driven Copper to replace Aluminum interconnec- tion as silicon technology is scaled beyond 0.25 μm. The front-end change, in turn, pushes wirebond pad pitch from above 100μm to 80μm-66μ range. This creates challenges for back-end to probe and wirebond at fine pitch geometry onto a readily oxidized Copper surface. After several re-metallization structures and types of metallurgy were evaluated, capping Copper bond pads with Aluminum was selected as the primary approach for probing and wirebonding Copper devices.