I am trying to develop a PDMS microfluidic device with soft lithography with a smaller features of using HMDS coating before photoresist coating. The smallest features in my device are 40 um2 squares. Now the problem is i am using HMDS 2ml on silicon wafer with 3000-5000 rpm for 30 sec and baking for 1-3 min at 100-150 'C. but the smallest features are lifting off.
Plz suggest something if anyone faced such thing before.
I know that there is room in optimizing baking and spinning timings which i am doing right now.
Let me know if there are other ways to get over it.
Hi Shahab Ud Din Khalil ,
It seems your surface is very smooth, high levels of humidity in the room or other factors. Can you please tell what is the surface on which you are coating HMDS and then PDMS?
If it is polished Silicon or metal surface, you can try multiple things.
Let me know how it goes.
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