[mems-talk] Releasing of the nitride suspended structure

[erkin seker]

Deepak - You may need to do critical point drying (CPD) to prevent the 
stiction during drying after the release.   I also heard rinsing the 
released devices in isopropanol several times, and then submerging them 
in hexamethyl disilazane (HMDS) reduces the chance of stiction.  The 
latter is known as poor man's CPD..  You should be able to find 
references to both of the procedures above with a quick literature search..

Good luck.

erkin

deepak agrawal wrote:
> Hi all,
> I am trying to release the nitride suspended structure. In that 
> structure I
> have 1.2um thick sacrificial layer of Aluminum on a silicon substrate 
> over
> which 0.2um thin structural layer of silicon nitride deposited by PECVD
> process. At the top, combined layer of chrome and gold are using to 
> get the
> top electrode. The top electrode and nitride pattern are etched by wet 
> and
> RI etching respectively.
> For releasing, ortho phosphoric etchant is using to etch the Aluminum 
> from
> the active area. The sample is placed in the etchant at 60c 
> temperature for
> 17 minutes followed by 10 minutes in DI water and 10 minutes in oven at
> 120c. I am not getting the released structure. The full pattern is 
> sticking
> with the surface of silicon. Is there any change in the process that i 
> can
> do to get the released device.