Marty,
The developer is a organic hydoxide do it slowly etchs many surfaces,
espcially silicon, Aluminum, oxide (slightly) GaAs and other stuff. this would
cause the surface to change.
Shay

Marty Patton wrote:

> I recently processed a wafer and mistakenly used the wrong mask at a
> certain step.  After removing the photoresist, I noticed that the areas
> which had been developed were hydrophillic and the areas which had been
> covered with resist were hydrophobic.  I don't know how long the effect
> lasts, but I dipped the wafer in water and dried it about 5 times and the
> effect remained.
> Conditions were AZ 351 developer and AZ positive resist on GaAs (with some
> epitaxial stuff on top).
>
> Marty
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