I have seen wrinkling effects during vaccum deposition on top of
photoresist, which we suspect is mostly due to outgassing of the
solvents from the resist film that are being trapped under the
deposited film. This is particularly bad with uncured SU8. Some
resists with low solvent content might behave better. Baking the
resist film in a vacuum oven for several hours before the sputter
deposition might also help. I have also found that evaporated films
are less prone to this because they are somewhat porous and leaves
room for the outgassing.


On Wed, Apr 23, 2008 at 10:55 AM, Kim Anh Bui  wrote:
>
> Good evening,
>
> I have a problem when depositing the membrane TiW used for RF MEMS Switch..
> We use sputtering for the deposition and TiW is deposited over a thin film of
PMMA.
> After the deposition the photo resist is all cracked.
> I don't know if the temperature is too hot or the pressure we use is not
suitable.
>
> Can anybody give me some advice?
>
> Thank you.
>
> Kim-Anh BUI-THI