I imagine you could play with the baking parameters. Reducing the soft-bake
should retain more solvent and reducing the PEB should lessen the extent of
cross-linking. However, I am not sure what happens over longer periods of
time (i.e. will it always reach a similar state after natural solvent
evaporation and cross-linking).

Perhaps you could try storing your devices to minimise long term effects.
They could be immersed in a liquid to reduce further solvent out-gassing and
stored in a fridge to reduce further cross-linking.


On Thu, May 7, 2009 at 02:27, Wong Wai Chi  wrote:

> Hi, everybody,
>
> I used SU-8 as devices material. I used PMMA as sacrificial material and
> release by using acetone, i can get good material properties after release,
> however, it become brittle after one week. did anybody face the same
> problem? how to solve it?
>
> thank
> WaiChi