Hi, How do I strip off thin flim that remained after a PI that contained silicon and was etched by oxygen plasma? I used some kind PI that contained Si as sacrifical layer. When i released the microstrure in oxygen plasma, I found that a layer of thin film remained on the substrate that could not be etched by oxygen plasma. Is there any way to get rid of that thin film? or strip that layer of thin film off by some kind of solution? chengzhengxi