Li Wangwrote:Hello, I want to protect my front side during KOH etching because there is polysilicon on it. I designed a jig which seal the wafer with O-ring and sandwiched the wafer in between two plastic pieces, fastened with six screws. But my problem is that the forces on the screw is kind of difficult to control and the wafers were broken several times in testing when the wafers were etched thinner. Another way I tried is PDMS protection. I put PDMS on the front side. The problem I met is that the PDMS will be detached from the wafer after I put the wafer into hot KOH for 2 hours. Anyone has any idea of KOH protection, please email me to help me out. Thanks a lot. Li Wang _______________________________________________ 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/ hi there try using black wax. hope you 'll get ur problem solved. Sunil MEMS & Microsensors Group CEERI, Pilani India --------------------------------- ALL-NEW Yahoo! Messenger - sooooo many all-new ways to express yourself