Also, if you happen to have access to a suitable oxygen RIE tool, that can be a much more aggressive clean of thick organics like SU-8 than a barrel asher. (Many DRIE tools have an O2 cycle available for the purpose of stripping the DRIE passivation layer and/or chamber cleaning.) But still beware of sputtering of the Cr by doing plasma cleans too often. On Mar 26, 2010, at 10:04, Andrew Irvine wrote: > Just to re-visit a wise warning from a recent poster, Piranha etch (at 110C or not) is seriously hazardous, and we need to be flagging up safety advice when suggesting stuff. > > I don't see a problem with using an oxygen asher, and if there is no problem (anyone?), do that instead, Mikas! > > Andy