Hello everyone,

I am using an ICP etcher with chlorine chemistry  to etch into GaAs with
ZEP/ PMMA polymers as the etch mask. After the etch I am seeing a thin layer
of white film on top, which  seems to go away if you scrath it away with
hand or wash it with ethanol. However, the film within the small features
does not seem to go away.

Has anyone had such experiences before. If so, please do let me know what
the film is and how it can be removed.

Thanks
Deepak