Hi, Bugnie, May I ask what type of the polymer is and the thickness? Typically, you can just try HF solution. Best regards, Fei -- Best regards, Yours sincerely Fei Wang ______________ Postdoctoral researcher, Dr MIC - Department of Micro and Nanotechnology Technical University of Denmark (DTU) Building 344, 1st floor, Room no. 130 DK-2800, Kgs. Lyngby Denmark Tel: +45 4525 6311 Fax: +45 4588 7762 Email: fei.wang@nanotech.dtu.dk http://www.nanotech.dtu.dk