We use KY jelly for this application also, as it can be "cleanly removed"!

We are etching through-holes in silicon wafers using 20% TMAH and a thermal
oxide etch mask.  The roughness on the backside of our wafers is causing
some problems with breakthrough of the oxide mask.  Does anyone know of a
material that we can paint, spin, or otherwise apply to the backside of our
wafers that will stand up to the TMAH and can also be cleanly removed?

Thanks,

Timothy A. Postlethwaite, Ph.D.
Chief Scientist
Constellation Technology Corporation
7887 Bryan Dairy Road, Suite 100
Largo, FL 33777
office: (727) 547-0600 x6177
fax: (727) 545-6043
tpost at
contech.com