Dear all,
I am trying to etch SiN membranes from the back side with ion milling .
The membranes are 100micron X 100micron made of 100nm LPCVD SiN on 500
micron Si wafer.
The membranes were fabricated using a standard KOH Si etching.
I noticed that the etch rate of the membranes (from the back side) is
almost 100 times smaller than the conventional etch rate of SiN with the
same conditions.
I would like to etch it faster. I suspect it is some kind of a charging
problem which is slowing the etching.
I tried to connect a ground electrode to both sides of the sample, but
this didn't help.
Has anybody experienced this problem or have an idea what to do?
Thanks,
Ronen