you should remove CR layer with CR MASK etchant. CR layer instantly oxidizes for several nanometer thick as soon as it exposed to the air. So, you should use CR Mask etchant. Good luck!! Sokwon Ho Yin Chanwrote: Hi all, Currently, I am etching PECVD oxide using standard RIE and Cr is the masking layer. However, I found that I cannot remove the Cr mask using Cr etch after going through the RIE process. I am wondering if there is anything happened on the Cr surface. I'd like to see if you could give me some suggestions on how to remove the top Cr layer. Thanks HY