In-Situ Measurement of Stress in Thin Films using Micromachined Quartz Bulk Acoustic Wave Resonators

In this paper, application of micromachined AT-cut quartz crystal bulk acoustic wave resonator cantilevers have been explored for in-situ thin film stress sensing. A novel method to compensate for mass-based frequency shifts has also been explored. Force frequency effect has been utilized to sense the stresses in thin films. Response of the quartz cantilevers to applied stress was systematically characterized by sputter depositing Metglas
^®
magnetostrictive films on the resonator surface and the application of magnetic field. An in-situ measurement of stress during deposition of tungsten thin film has been shown.