Dear MEMS ;
           I'm searching a passivation material for Si KOH-etching.
           It takes a long time for Si etching and
           I must protect front side of wafer.
           Al layer is deposited on the Front side.
           Does anyone tell me the material and method of protection?

            Si etch thickness ; 450 micron
            Si etch solution ; KOH + IPA

           I'll wait for your quick response.


           Sincerely yours.