Stress Isolation Structures in MEMS Gyroscope Packages

This paper describes the impact of lead frame design to minimize mechanical and thermal stresses to a MEMS (micro-electromechanical systems) gyroscope in a plastic premold cavity package. Design ideas for incorporating stress-isolation structures by etching the die paddle in a lead frame were evaluated with finite element modeling (FEM) and experimental verifications. The results showed that the null drift due to external mechanical stress was significantly improved by more than one order of magnitude, and the temperature variation of the device output was also improved by 30%, both by mounting the device on the lead frame etched with stress-isolation structures.