Revisiting Decapsulation Mechanisms and Backside Analysis in a Power Switch Device with Highly Cross-Linked Molding Compound
Revisiting Decapsulation Mechanisms and Backside Analysis in a Power Switch Device with Highly Cross-Linked Molding Compound
Wednesday, October 7, 2026: 9:20 PM
Summary:
Modern integrated circuits (ICs) increasingly incorporate advanced packaging materials and complex architectures that challenge conventional failure analysis (FA) techniques, particularly during decapsulation and sample preparation. This study addresses these challenges for a power switch device packaged with Sumitomo G712, a highly cross‑linked, acid‑resistant molding compound. Although G712 molding compound has been successfully decapsulated in previous work, the response observed in this device was significantly different. Under conventional mixed‑acid decapsulation conditions, the molding compound exhibited increased resistance to etching, resulting in incomplete material removal. This indicates that the effective etching behavior is influenced not only by the material itself but also by package architecture and device-specific conditions, which can limit acid interaction and accessibility. A systematic evaluation of decapsulation recipes identified insufficient chemical contact time as the primary limitation of automated processes. An optimized extended‑contact chemical approach was developed, enabling effective molding compound removal while maintaining wire integrity, as verified by wire pull testing (WPT). A separate controlled mechanical backside preparation method was also developed for the complex multi-material structure, including molding compound, copper heatsink, and ceramic layers. Electrical characterization before and after backside exposure showed no measurable degradation. Backside FA techniques including infrared (IR) imaging, thermography, laser emission microscopy (LEM), and optical beam–induced resistance change (OBIRCH) were successfully performed. These results demonstrate a practical methodology for enabling both topside bond integrity evaluation and backside failure analysis in complex power device architectures, where conventional decapsulation approaches are insufficient.
Modern integrated circuits (ICs) increasingly incorporate advanced packaging materials and complex architectures that challenge conventional failure analysis (FA) techniques, particularly during decapsulation and sample preparation. This study addresses these challenges for a power switch device packaged with Sumitomo G712, a highly cross‑linked, acid‑resistant molding compound. Although G712 molding compound has been successfully decapsulated in previous work, the response observed in this device was significantly different. Under conventional mixed‑acid decapsulation conditions, the molding compound exhibited increased resistance to etching, resulting in incomplete material removal. This indicates that the effective etching behavior is influenced not only by the material itself but also by package architecture and device-specific conditions, which can limit acid interaction and accessibility. A systematic evaluation of decapsulation recipes identified insufficient chemical contact time as the primary limitation of automated processes. An optimized extended‑contact chemical approach was developed, enabling effective molding compound removal while maintaining wire integrity, as verified by wire pull testing (WPT). A separate controlled mechanical backside preparation method was also developed for the complex multi-material structure, including molding compound, copper heatsink, and ceramic layers. Electrical characterization before and after backside exposure showed no measurable degradation. Backside FA techniques including infrared (IR) imaging, thermography, laser emission microscopy (LEM), and optical beam–induced resistance change (OBIRCH) were successfully performed. These results demonstrate a practical methodology for enabling both topside bond integrity evaluation and backside failure analysis in complex power device architectures, where conventional decapsulation approaches are insufficient.