3-d Micromachined Spherical Shell Resonators with Integrated Electromagnetic and Electrostatic Transducers

(a) Before glassblowing (b) After glassblowing Figure 2: Photographs of fabricated 3-D spherical shell resonators with integrated electrostatic transducers. This paper presents a new paradigm for design and fabrication of 3-D spherical shell resonators. The approach uses pressure and surface tension driven plastic deformation (glassblowing) on a wafer scale as a mechanism for creation of inherently smooth and symmetric 3-D resonant structures with integrated electrodes. Feasibility of the new approach was demonstrated by fabrication and characterization of Pyrex glass spherical shell resonators with millimeter scale diameter and average thickness of 10-20 μm. Integrated 3-D metal electrodes were used to actuate the two dynamically balanced 4-node wineglass modes. For 1 MHz glassblown resonators, the relative frequency mismatch Δf/f between the two degenerate wineglass modes was measured as 0.63 % without any trimming or tuning. The intrinsic manufacturing symmetry and high aspect ratio transducer architectures of the proposed technology may enable new classes of high performance 3-D MEMS for communications and navigation applications.