Monitoring of wafer thinning induced in-die mechanical stress with embedded sensors for heterogeneous integration

The paper describes a new type of in-die monitor sensors for in-situ detection of changes in the level of mechanical stress experienced by silicon product die. Multiple sensors have been distributed across a 3x3 mm2 die manufactured with 12nm FinFET technology. The changes in mechanical stress were monitored with measurements at wafer-level, and after dicing and thinning, and chip packaging. The results showed that the stress change depends on wafer thinning, and after packaging has a nonuniform distribution across the chip. We propose to use this characterization solution for process optimization for heterogeneous integration and monitoring chip packaging through dicing, bonding, and molding.