High temperature micro-glassblowing process demonstrated on fused quartz andULE TSG

摘要

We report, for the first time, a MEMS fabrication process for building atomically smooth, symmetric 3-D wineglass and spherical shell structures, using low internal loss materials, namely fused quartz andultra low expansion titania silicate glass (ULE TSG). The approach consists of three major steps: (1) adeep fused quartz cavity etch, (2) plasma activated bonding of fused quartz to fused quartz or TSG and(3) a high temperature (up to 1700?C) micro-glassblowing process. An in-house process capability of1800?C glassblowing with a rapid cooling rate of 500?C/min was developed. Feasibility of the processhas been demonstrated by fabrication of fused quartz and TSG micro-glassblown structures. Spheri-cal and inverted-wineglass shells with self-aligned stem structures were fabricated using this process.The approach may enable new classes of TSG and fused quartz MEMS devices with extremely low sur-face roughness (0.23 nm surface average), intrinsically low thermoelastic dissipation (QTED> 5E+10), andhighly symmetric structures (radial error < 500 ppm).