Hi all,

i need to thermal evaporate a metallic mask on a polished silicon wafer.
The mask should withstand 40% KOH etch for 5 hours.
I tried 20/30 Cr/Au, but it seams that it is not working: after about 1
hour etch many pinholes are generated in the Cr/Au layer, KOH penetrates
such pinholes and etch silicon.

Any suggestion on how to improve the resistance of Cr/Au layer ?
Any alternative to Cr/Au ?

Thanks,
Andrea