Gareth,
thanks for your reply,
that is true I have not use any filters during exposure, I think a good
filter which cut off the UV light below 350 will help.

And thank you Eowin, thanks for your suggestion, but I want to make a PDMS
channels which may bond with a ITO glass substrate, and I use a silicon
waffer as a sub for SU-8 PR, the silicon waffer is opaque one and difficult
to observe under a microscope.
I think I should try a filter.


2008/10/29 eowin rohan 

> Hello Liang,
>
> I think Gareth is right, it looks like a lot of thickness (50um) and too
> much short development time, especially if you take into account the sieves
> dimensions (around 20um). It will be difficult develop the unsposed parts...
> or perhaps impossible at all: You have light scattering so it is possible
> that at any depth some photons are reaching the SU-8 under de sieve mask, so
> could be polymerised and so it will very difficult develop it.
>
> I really don´t understand exactly your channel-sieve sistem, especially the
> arc-sieve geometry, but looks like something like a block with "holes" with
> arc shape. You want the SU-8 just as a mould to get the chanel with "walls"
> with arc shape in PDMS. You can´t get holes from one side to other in su-8,
> so your walls in PDMS are not so high as you want, and cells flow away
> freely, isn´t it?Well, why not make the channel directly in SU-8? The only
> thing you will need is invert the mask, leaving the sives clear and the
> channel dark. I hope this idea works well for you.
>
> regards
>
> Eowin

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赵亮
南京大学化学化工学院
Liang Zhao
School of Chemistry and Chemical Engineering, Nanjing University