Thanks a lot. I tried the recipe with CHF3:O2=10:1. It looks not very helpful. I see if Shipley PRX solution works for me. ----- Original Message ----- From: "Scott McWilliams"To: "General MEMS discussion" Sent: Wednesday, August 16, 2006 9:15 AM Subject: Re: [mems-talk] How to remove the PMMA etching residue. > Hi Xiaojing, are you using CF4 and CHF3 without oxygen mixed in? I have > had difficult to remove polymers form using both CF4 and CHF3 while > etching SiO2. Can you reduce the selectivity to the PMMA a little bit and > add some oxygen to the etch? I have also had some success using Shipley > PRX solution to remove the etch residue. PRX does etch SiO2 very slowly > but didn't matter on my application. >