MEMS transducer device and fabrication process

摘要

A micro-electromechanical system (MEMS) device, for example a transducer or capacitive microphone, comprises a membrane or diaphragm layer 1, and a back-plate layer 7 formed over the membrane layer. The membrane layer comprises an outer portion 1b, an inner portion 1a, raised relative to the outer portion, and a sidewall 1c for connecting the inner portion and the outer portion. The sidewall is non-orthogonal, or sloping, relative to the outer portion. Other embodiments allow for a back-plate with sloping sidewalls, or for the membrane to be connected to the side-wall of the back-plate layer. There is also provided a fabrication method for the device involving depositing and shaping a sacrificial layer. This process could use various steps such as masks, etching, resist layers, curing and thermal treatment.