Influence of test speed on the bonding strength of glass frit bonded wafers

Abstract

Wafer bonding is a key technology in the manufacturing of micro electro mechanical systems (MEMS). It describes various techniques of joining two wafers with or without thin intermediate layers on industrial scale. Thereby, glass frit bonding is used in a wide range of applications, especially for the encapsulation of surface mechanical sensors like gyroscopes and acceleration sensors. The strength of the bonded interface directly affects the reliability of glass frit bonded MEMS devices. Therefore, it has to be detemined experimentally. The fracture toughness and the shear strength are suitable values to characterize the bonding strength. They enable the comparison of different bonding technologies and process parameters during bonding as well as an estimation of lifetime for the whole microsystem. Because of the requirements of quality control during the manufacturing of micro systems, a large number of MEMS devices and test structures have to be characterized. To optimize the yield and provide adequate and reliable material properties, the influence of the testing speed on the micro chevron measurement and the shear test has to be analyzed