Demonstration of 1 Million <inline-formula> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula>-Factor on Microglassblown Wineglass Resonators With Out-of-Plane Electrostatic Transduction

Abstract

In this paper, we report Q-factor over 1 million on both n = 2 wineglass modes, and high-frequency symmetry ( f/ f ) of 132 ppm on wafer-level microglassblown 3-D fused silica wineglass resonators at a compact size of 7-mm diameter and center frequency of 105 kHz. In addition, we demonstrate for the first time, out-of-plane capacitive transduction on microelectromechanical systems wineglass resonators. High Q-factor is enabled by a high aspect ratio, self-aligned glassblown stem structure, careful surface treatment of the perimeter area, and low internal loss fused silica material. Electrostatic transduction is enabled by detecting the spatial deformation of the 3-D wineglass structure using a new out-of-plane electrode architecture. Out-of-plane electrode architecture enables the use of sacrificial layers to define the capacitive gaps and 10 μm capacitive gaps have been demonstrated on a 7-mm shell, resulting in over 9 pF of active capacitance within the device. Microglassblowing may enable batch-fabrication of high-performance fused silica wineglass gyroscopes at a significantly lower cost than their precision-machined macroscale counterparts.[ 2014-0251]Index Terms-Micro-glassblowing, 3-D MEMS, wineglass resonator, degenerate mode gyroscope, fused silica.

Chip-scale high Q-factor glassblown microspherical shells for magnetic sensing

“…At room temperature thermorefractive noise will likely be the dominating noise source 28 . Glassblown fused silica microbubbles have been previously demonstrated by other authors for acoustic resonance phenomenon 29 . It is likely that very high Q-factor fused silica WGM optical resonators are achievable using this process, owing to the lower optical absorption coefficient for fused silica compared to borofloat.…”

An Investigation of Processes for Glass Micromachining

“…The glass structure can be formed by using the glass reflow process; nevertheless, its process faces difficulty when the glass fills into small patterns [19,20]. The fabrication of glass capillaries based on a glass reflow into a small trench has been introduced in our previous work [25].…”

“…Several techniques of glass micromachining currently exist, including drilling [13], milling [13], laser [13], sandblasting [13], wet etching [14,15], dry etching [16,17,18], glass molding techniques [6,19,20,21,22], etc . The first three methods are usually used for quite large pattern sizes and face problems with small structures.…”

“…Due to the expansion of the trapped gas in the cavities, the glass is blown into three-dimensional spherical shells. High Q factor micro-glass-blown wineglass resonators have been presented [20]. Additionally, double-sided micro-lens array have been successfully demonstrated using glass blowing [21].…”

Micromachined high-Q fused silica bell resonator with complex profile curvature realized using 3D micro blowtorch molding

“…FS wineglass and birdbath resonators have been demonstrated using reflow molding techniques based on the expansion of trapped gas molecules [1] and controlled vacuum molding [2], respectively. In the first technique, the shell formation is driven solely by uniform gas pressure across the shell, so it has limited shape controllability; the second technique relies not only on the pressure gradient but also on the transient heat transfer between the hotter, reflowing shell and the colder mold.…”