Hi everyone,
I am currently trying to pattern PEGDA using photolithography for further cell patterning (as PEGDA has been used as a cell repellent material). I am able to do correct patterning, meaning the features are well transferred onto the PEGDA film but I have some issues during the development of the film (using DI water) as after removal of the non cross-linked PEGDA, I still have some polymer where it is not supposed to be (see attached picture)...
Also, as the film needs to be in contact with the shadow mask before UV exposure, I also have some issues with the "lift-off" after exposure, as the substrate sticks to the mask and thus leading to "holes" in the pattern when detaching it... I also tried to coat the mask with FDTS (hydrophobic silane) to make it non-adhesive but did not really worked...
Does anyone have some suggestion on how can I effectively develop the PEGDA films ? Any ideas would be really helpful ! Thanks in advance ! :)
Best regards,
David
For the sticking problem, try spin coating your mask with PVA. There is some possibility that you are seeing surface activation of you PEGDA. You may need to passivate your substrate. To test this, go through your process excluding the UV exposure and see if you are left with a residue on your substrate. This may also explain the mask sticking problem as well.
Hello,
I am actually facing the same problem as David. I would like to do hard contact or vacuum contact photolithography on PEGDA/DMPA on my ATO film and unfortunaletly the pegda stickes to the mask and I can not avoid it. Using soft contact or gap exposure is not suitable for me due to the 10um resolution that I require. Could anyone help how to avoid PEGDA sticking to the photomask?
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