You should explain if you heat the solution while etching. ---------- Initial Header ----------- >From : mems-talk-bounces@memsnet.org To : "Qiao Dayong" dyqiao@nwpu.edu.cn,"General MEMS discussion" mems- talk@memsnet.org Cc : Date : Tue, 26 Dec 2006 10:38:21 +0530 Subject : Re:[mems-talk] BHF precipitates ? > Dear Friend, > Are you filtering the NH4F and DI water solution or not? > We are filtering the solution and then mixing the resultant soln. with HF acc. > to our concen. requirement. We have not faced any problems. > Try it.