Digital Manufacturing of Fused Quartz Resonant MEMS with Enhanced Surface Quality

We present a fast and precise laser-based digital manufacturing process for glasses. The process is based on a 3-dimensional Femtosecond Laser-Induced Chemical Etching (FLICE) capable of building Micro-Electro-Mechanical Systems (MEMS) from a single piece of transparent dielectric material, such as glass. For the first time, we demonstrated manufacturing of devices with over 200 μm in thickness and over 15:1 Aspect Ratio (AR) using Fused Quartz (FQ) as the structural material. In the proposed process, Hydrofluoric acid (HF) erosion of FQ wafer surfaces was utilized to expose the openings of the laser-inscribed micro-trenches for the subsequence wet etching. It eliminated the laser surface damage (e.g., cracks, subsurface damage, material deformation, etc.) and material redeposition due to low fluence laser initiation caused by impurities on FQ wafer surfaces. To illustrate this new capability, we designed, manufactured, and demonstrated a micro Disk Resonator Gyroscope (DRG) with over 1 M in quality factor. Our results demonstrate a potential for the process to become an alternative to commonly used plasma etching techniques for machining MEMS from quartz, Pyrex, and other transparent materials.