Packaging effects on Q factor of MEMS resonator

Abstract

Quality factor of resonators has been one of the most important parameters because it determines sensitivity of the device, espacially in the case of vacuum-packaged MEMS resonators. Typical energy loss mechanisms of vacuum-packaged MEMS resonator are supporting loss and TED. Those mechanisms can be affected by package structure because the package structure consists of acoustic wave path as well as thermal dissipation path. Through severe numerical simulations, temperature-dependency of Q factor including thermal deformation of its package were obtained, where TED was the limiting mechanism and it decreased with the temperature increase. Paste used to adhere MEMS die to the package has also significant effects on Q factor because it works as one of thermal resistors for TED mechanism. Therefore, it's required to optimize package structure, number and location of adhesive paste, and MEMS resonator itself in order to maximize Q factor.