Hi Prakash,
I haven't tried SU-8 on thermal oxide specifically, but I'd suggest
trying a dose of strong oxygen plasma on the oxide surface before coating.

-Joe

Prakash Mukre wrote:
> Hi All,
>
> I am trying to deposit SU-8 over thermal oxide. SU-8 is part of the final
> device I am fabricating, so I want it to adhere to the substrate strongly.
> But with my current recipe SU-8 delaminates after development. Following
> are
> the some process specs I am following.
>
> SU-8 2100 Thickness: 200-250um
> Softbake: 15min @65C,  100min @95C.
> UV Dose: I have tried 400mJ/cm2 to 1000mJ/cm2
> Hard Bake: 5min @65C, 20min @ 95C.
> Development time: 10-20min.
>
> I have tried using primers like HMDS, P20. Also I have tried using Omicoat.
> What could be the possible reason for this? or SU-8 does not adhere to
> thermal oxide at all?