Hi all, I was wondering if anyone knows a good etchant for Aluminum Oxide. My process is as follows: 1- Deposit Aluminum Oxide on Silicon Wafers using sputtering or evaporation 2- Spin 1~1.3 u HRP-504 on Si+AlOx wafer( on top of AlOx layer) 3-UV expose and Develope to produce the desired patterns on the resist(HRP-504) 4-Etching ????? I don't know what etchant I can use to etch AlOx. It should be something that doesn't eat up Silicon or HRP 504. and only works on Aluminum Oxide. Thank you for your comments. Seyed