Hi Gavin,

  Best results are obtained when you pour it directly from the bottle. But make
sure no air bubbles are introduced when you do so (it helps when the bottle
neck is wider).Pipettes dont help as SU-8 is very viscous and inevitably
introduces air bubbles in this method. For uniformity, we have found out
(through a lot of trials) that increasing the acceleration speed and quantity
of SU-8 helps (have to trade off with thichkness of SU-8 desired, though).

Amitha G
Louisiana Tech Univ


Dear all,

I am a novice on using SU-8. I've ordered MicroChem 2025 and tried to
spin-coat a 2" wafer. Since SU-8 is really thick and sticky, I applied it onto
the wafer surface before spinning with a small beaker instead of a pipette. I
also slowed down the accelerating ramp of the spinning chuck. But I've never
been able to get a uniform layer or smooth surface without streaks. I know the
problem might be in the bubbles generated when applying the SU-8, which is
kinda unavoidable. Anyone has a better idea on the *tool* (I mean beakers,
pipettes, etc) for applying SU-8? Or anyone know the secret of getting a
uniform layer?

I guess the answer could be somewhere in the archive. But I just need an
answer really quickly. Thanks very much.

Gavin


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