Hello Lin, If it's just fused quartz, it should be etching WAY faster than it is. Something's coating it, or something's wrong with you HF. If you're trying to etch single-crystal quartz, a little heat will go a long way. Dr. Hiroshi Yoshi wrote a paper about etching single-crystal quartz about 6 years ago. If I remember correctly, he was using BOE heated in a boiling water bath. Be careful with this stuff. I inquired with my lab manager about doing this with concentrated HF, and he told me no way without a teflon coated reflux ($5000 at the time). Hope this helps, Jesse Fowler "Lin Yu"Sent by: mems-talk-bounces@memsnet.org 09/09/2006 15:11 To Subject [mems-talk] Wet etching of Quartz wafer Hello, I've been trying to etch quartz wafer using HF or BHF. But the ethcing rate was really slow, 1000A in 2 hours. Does anyone know a stable and repid way to etch quartz?