Dear All, I am trying to make a nanowire grating using a simple process. I am spinning a layer of photoresist on top of a ~50nm layer of silver or aluminium. The photoresist is then exposed and developed to have a sinusiodal profile, of between 200 and 300nm pitch, where the troughs of the profile expose the metal underneath. I then aim to etch the exposed areas of metal using typical chemistries such as H3PO4:HAc:HNO3:H2O to leave an array of parallel metallic wires of the same pitch. However, I seem to be having problems and never seem to be able to etch the exposed areas. I have looked into this on the web and came across a short presentation. The link is: ccms.ntu.edu.tw/~chihiwu/ch09%20rev3.ppt and on the slide discussing the disadvantages of wet etching they state: "Can’t pattern sub-3micro-m feature" I have worked out they are at the National Taiwan University, but I can not find the actual author's name or email address to enquire directly to them, so I thought I'd try to see if anyone else can confirm their statement. Can anyone tell me if this is correct and may be the reason why I cannot wet etch my 200-300nm profiles, and if so perhaps provide a reference I can look up and quote. Thank you very much for your time. Martyn Gadsdon