Vijay,
A good non-contact method to measure the temperature of a wafer is by a
pyrometer.  They do face the limitation of not working well at the lower
temperature range and assume that you know the emissivity of the substrate.

In your case, wafers with polished/non-polished and with thick oxide, would
have varying emissivities.  An equipment vendor I know of (I think most of
this technology is patented by the vendor), solves the problem by using a
highly reflective area on the back side of the wafer, in effect, creating an
approx ideal black body.  Of course, it is not perfectly ideal, and
non-idealities are compensated for by using a emissometer.

The following Omega's site might have additional info for you:
http://www.omega.com/pdf/temperature/Z/pdf/z067-069.pdf

Goodluck.
Jaideep


-----Original Message-----
From: vijay parihar [mailto:vpariha@ces.clemson.edu]
Sent: Monday, July 26, 1999 3:55 PM
To: MEMS@ISI.EDU
Subject: Non-contact temperature measurement of silicon wafer


Hi

I was wondering what might be the best method to do the non-contact
measurement of
silicon wafer temperature in the range of 50 degree C to 600 degree C on
the polished
side of the wafer as well as non-polished side of the wafer. Polished side
will be
coated with 100nm thick oxide.

Cheers,

vijay