Try evaporate CrAU or magnetron sputtered CrAu. With 48% HF -----Original Message----- From: mems-talk-bounces+shay=mizur.com@memsnet.org [mailto:mems-talk-bounces+shay=mizur.com@memsnet.org] On Behalf Of Xin Yan Sent: Monday, December 13, 2010 2:50 PM To: mems-talk@memsnet.org Subject: [mems-talk] Adhesion problem during 7740 glass wafer wet etching process Hi everyone, i want to etch the 7740 about 4 to 20 um deep. Using Cr with Photoresist 5214E as the mask, Cr layer was produced by DC sputtering about 200nm thick. The etchant is 1 HF : 2 HNO3 : 2 H2O to get high etch rate about 2um/min to the 7740. we met a problem that Cr can not stand in this solution even 2minutes. After about 2 min, Cr begin to peel off. In the 49%HF without HNO3, Cr cannot stand even 1minutes. what cause the Cr so unstable or it is supposed to be like this? or i need to change the etchant ? Thank you Yan Xin