Non-destructive In-line IMC Thickness Measurement Using Acoustic Metrology for 3D Stacking

Abstract

Abstract The constant demand for small-feature-size, high performance and dense I/O applications have necessitated the development of fine-pitch vertical interconnects for 3-D integration. Microbumps and through silicon vias enable the high-density vertical interconnects. As microbumps scale, intermetallic compound formation during thermocompression bonding and its impact on reliability is a concern. In this paper, we describe the application of picosecond acoustic metrology technology as a viable option for non-destructive characterization of the intermetallic compounds. The small spot size technology allows measurement on small bumps, with very good accuracy and repeatability.