Test Method for Contactless On-Wafer MEMS Characterization and Production Monitoring

Microelectromechanical systems (MEMS) are widely utilized in various devices ranging from consumer electronics and medical devices to modern industrial equipment. Their fabrication with the help of semiconductor technology leads to very low cost devices. However, the fabrication test systems need to be extended to cover the mechanical domain of MEMS devices. Therefore, this paper presents a new concept that is able to evaluate the stiffness of silicon membranes in MEMS microphones. Due to the use of electromagnetic waves in the millimeter-wave spectrum, an optical line of sight is not necessary. The test setup can be parallelized to improve the throughput, and it can gain important feedback information to tune operating parameters of the production process.