Personally I wouldn't keep it in the fridge if it's being used regularly as
you will have to wait for it to warm up. As well as condensation, if it's
still cold you may not get the desired thickness.

Additionally, I have used bottles of SU-8 stored for many years at room
temperature well beyond their expiry dates with no noticeable bad effects.
Keeping it clean and dark is probably more important.
We decant the SU-8 into a small, wide mouthed plastic bottles for daily use..
However, decanting tends to introduce bubbles which can ruin your film. We
need to let it settle for several hours for the bubbles to come out. I would
normally pour direct from the bottle but because we have a recessed spinner,
the size of the bottle prevents me getting close to the wafer surface and
leads to even more bubbles being introduced. The small bottles allow me to
get really close.

As for 2100 vrs 2075, you are probably right about film thickness accuracy
at low rpm. However, I'm beginning to suspect other factors have
a bigger influence (i.e. baking conditions and ventilation effects) so
perhaps you shouldn't worry too much about it.



2010/2/1 

> Hi,
>
> normally it is a good advice to keep resists in the fridge. But, DO NOT
> open
> cold bottles. Water will condense at the cold walls and you will
> contaminate
> your resist. Thus, wait until bottle is at ambient temperature before
> opening, then you have a more liquid SU-8 as well.