An In-Situ Measurement Method for Thermally Induced Packaging Stress in Distributed RF MEMS Phase Shifters

In this paper, an in-situ measurement method for thermally induced packaging stress in the distributed RF MEMS phase shifters is presented. Base on the analytical relation among the actuation voltage, the stiffness coefficient of and the resident stress on the beams of the devices, the thermally induced packaging stress from the die-attaching process in the device can figure out by measuring the increased value of the actuation voltage for offsetting the deviation of the phase shift of the device after the packaging process. A case study is conducted to demonstrate the principle and procedure of the proposed measurement method. And the variation of the actuation voltage can also be used as a bias voltage to offset the deviation of the phase shift characteristic of the device due to the thermally induced packaging stress.