Silicon to Steel, Rapid Bonding

A rapid bonding process for installing vacuum-sealed MEMS strain sensor modules to mechanical components is being developed. This innovative process will be developed to replace conventional adhesive-based approaches. In particular, the silicon to steel bond must achieve these stringent requirements: long life, resistance to chemicals, short bonding process time, and a wide range of storage temperatures. To ensure that the strain within a steel substrate will be accurately measured by the MEMS strain gauge, properties of the bond layer between silicon and steel are observed and determined. A uniaxial strain rig is used to measure the shear strength and modulus, creep, and hystersis of silicon-steel bonds within a temperature-controlled environment. A micro Newton strain gauge is used to characterize the shear modulus and strength of microfabricated bonds of various shapes and widths. An overview of MEMS style rapid bonding techniques, along with a discussion of bonding materials and methods, will be presented.