Hello,

I want to protect my front side during KOH etching because there is
polysilicon on it. I designed a jig which seal the wafer with O-ring and
sandwiched the wafer in between two plastic pieces, fastened with six
screws. But my problem is that the forces on the screw is kind of difficult
to control and the wafers were broken several times in testing when the
wafers were etched thinner. Another way I tried is PDMS protection. I put
PDMS on the front side. The problem I met is that the PDMS will be detached
from the wafer after I put the wafer into hot KOH for 2 hours. Anyone has
any idea of KOH protection, please email me to help me out. Thanks a lot.

Li Wang