Hello everybody,

I need some inputs on gold etching. I have an SOI wafer with evaporated
Cr/Au (40nm/500nm). The wafer was patterned using AZ9260 (6 micron thick).
When I etched the exposed gold layer using pottassium iodide etchant (KI3)
for about 55 seconds, I noticed large exposed areas (circles of 250 microns
radius) are etched slower than the small narrow crevices (2-10 microns
width) on a wafer. I was expecting exactly opposite behavior in the etch lag
because, it should take a relatively more time for the etchant to reach the
narrow crevices. Can anyone explain me why I notice this behavior? Also I
would appreciate if anyone can suggest a suitable way to minimise the etch
lag between different features.

Thanks,
Prasanna