Process flow improvement on a bulk micromachined gyroscope

An introduction of a bulk micromachined frame gyroscope and the efforts made to lower the footing effect during deep reactive ion etching (DRIE) is featured. The gyroscope is driven into oscillation electrostatically and senses rate signal by the varying overlapped area of the electrodes, which eliminates the nonlinear behaviour of sensing the varying gap. Damping factors for the driving and sensing modes are low due to the slide-film damping, resulting in high quality factors in the atmosphere. A large proofmass can be made by DRIE, which also ensures a large pull-in voltage. The footing effect during fabrication has been greatly reduced by the improved process flow, which also increases the proof mass by 50%. Thus device quality and yield rate are both improved. Functional results of an improved prototype are given.