Hi Daniel, Thanks for your reply. I found this procedure of bonding in one of the papers & hence applied it. Since I am using DI water for bonding so I dont think that minerals must be causing the white film. I have read that the white film basically indicates the unbonded area though I am not sure. I am still trying to eliminate the white film. ________________________________ From: Daniel LloydTo: "gau_s15@yahoo.com" Sent: Mon, July 18, 2011 10:19:53 AM Subject: RE: [mems-talk] Bonding of Silicon and glass substrate both coated with SU-8 Hi Gauri, I know its a while after your question but I haven't seen any replies. I've no experience with bonding but I'm not sure what the oxygen plasma treatment will achieve, except that it may possibly etch the top surface of the SU-8. I would then expect the white film left by the water to be any minerals left when the water is evaporated by the baking, which would explain why you don't see this with the DI water. This would also leave a thin layer of material to create your bond. As I said I haven't any experience with bonding so may be using my knowledge to go off on completely the wrong path. Good luck, Daniel.