Hey all, this may sound a bit weird, but I have my reasons: I need to wet-etch (phosphoric acid as enchant) an aluminum wafer. I must use an inorganic mask for the purpose, but my favorite would be chromium: deposit a thin layer of chromium on my aluminum wafer, pattern it with ceric ammonium nitrate and then etch the aluminum with phosphoric acid. I need to etch some 100 um of aluminum. The big problem I have is, I don't know whether there will be some electrochemical effects that would prevent either of the etching processes. Let me know before I go and waste several hours in a futile attempt. By the way, happy and fruitful New Year - good health and successful experiments going forward! m