Overview of 3‐D Shell Implementations

Motivated by the proven performance of macro‐scale Hemispherical Resonator Gyroscopes, there has been a growing interest in 3‐D micro‐electromechanical system micro‐shell resonators for use in timing and inertial sensing applications. This chapter reviews the recent advances in 3‐D shell micro‐technology. Starting with a brief history of macro‐scale shell resonator gyroscopes, it reports novel fabrication processes and architectures for implementation of whole‐angle gyroscopes at micro‐scale. Majority of the focus is directed toward development of a surface tension and pressure driven micro‐glassblowing paradigm, which is envisioned to serve as an enabling mechanism for wafer‐scale fabrication of 3‐D micro‐wineglass gyroscopes. Surface‐micro‐machined micro‐shells are almost exclusively fabricated by depositing a thin film onto a predefined mold with a sacrificial layer to create the resonator element. In order to achieve functional resonators based on micro‐shell structures, efficient methods for transduction are required.