There is very few polymers (if there are any) which would survive in TMAH even they are not being directly dissolved by it. Parylene is perfectly inert in TMAH but patterned parylene after after being exposed peels off completely (in a few seconds) as it is not the polymer but its interface with silicon which suffers. Regards Pavel __________________________________ Do you Yahoo!? The New Yahoo! Search - Faster. Easier. Bingo. http://search.yahoo.com