About 85 +-2 deg. C is perfect. Though I use a slightly different recipe: 8 H2O: 7 HCl : 1 HNO3 by volume. Good luck, Mike >>> yungsik@amed.snu.ac.kr 02/17/03 06:21PM >>> Dear I'm trying to etch Pt layer on a glass wafer. I sputtered Ti and Pt 1000A and 3000A thick respectively on a 4" glass wafer. I patterned with AZ1512 first and then tried to etch the Pt layer with aqua regia( HCl:HNO3=3:1). But I couldn't identify any etching of the Pt. Do I need to heat the aqua regia to etch the Pt layer? If I do not raise the temperature, can't I etch the Pt? Then What is the proper temperature? I hope to get your reply soon... Thank you... Have a nice day~~!! Shin, Young Shik, Master Candidate Micro-BioMechanics Team, Advanced Machine Element Design Laboratory, School of Mechanical & Aerospace Engineering, Seoul National University yungsik@amed.snu.ac.kr youngshik@digital-bio.com _______________________________________________ MEMS-talk@memsnet.org mailing list: to unsubscribe or change your list options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk Hosted by the MEMS Exchange, providers of MEMS processing services. Visit us at http://www.memsnet.org/