Thanks all for your replies. Based on different replies, I feel the that best solution is to use a solid chuck with sealing rings to protect one side. Does anyone any company which provides these type of chucks in US? Thanks _______________________________________________ Hosted by the MEMS and Nanotechnology Exchange, the country's leading provider of MEMS and Nanotechnology design and fabrication services. Visit us at http://www.mems-exchange.org Want to advertise to this community? See http://www.memsnet.org To unsubscribe: http://mail.mems-exchange.org/mailman/listinfo/mems-talk