Hi Mohana,
Not sure why you've filed this under RF design, because it's not really RF related. Anyway, there's an example of using SpectreMDL to do SNM measurements. See:
<MMSIMinstDir>/tools/spectre/examples/MDL_workshop
There's a pdf in there, and a gzipped tar file containing an example database. In the version I looked a, page 63 of the PDF talks about doing SNM
Regards,
Andrew.