Daxiang:

Try having LPCVD nitride deposited from an outside group to insure proper
quality. As you noticed when too much Hydrogen or Oxygen is incorporated into
the film it change it dramatically. That is why using an HF acid test to make
sure your nitride is resistant will make sure it will hold up to KOH as well.
Bob Henderson

-----Original Message-----
From: D. Zhou 
Subject: Re: [mems-talk] Any metal as KOH masking layer?

Hi Bob,

Thanks for your message very much. I deposited a 250nm-thick Si3N4 as the
masking layer but it could not provide sufficient protection during the KOH
ething. This is partly becaust SiN deposited in our group is not pure Si3N4, but
contains a large amout of oxygen. The patterns are not well difined using this
SiN as the mask. So I am going to try some metals as the masking layer, say
Au/Cr or Au/Ti. Any suggestions? Thanks a lot.