Mr. Hiltman,

        Do you know who makes a reasoanbly price microscope temperature
        measurement system ? The machines we got quotes from cost
        about $150K which I think is way too much.

                                                -C. H. Mastrangelo
                                                -university of Michigan

On Sat, 14 Aug 1999, Kai Hiltmann wrote:

> Jaideep Mavoori wrote on 2 Aug 1999:
> > 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.
> >
>
> Hallo,
> I am sorry I missed to answer this posting sooner - I had intended to
> do so.
> We are using an Agema thermographic system with microscope
> lens and working in the far infrared range to characterize our
> devices. We have made good experiences with this system and have even
> been able to measure the temperature distribution on 20 micrometer
> thick membranes with an accuracy (not resolution) of 1 K. We have
> found, though, that the emittance of nearly every specimen is
> different since it depends on many factors. A further difficulty lies
> in the fact that silicon is partially transparent in the infrared so
> that radiation from background is measured, too. We therefore start
> measuring the emittance first which requires exact calibration. In
> the case I mentioned, this was only possible by using integrated
> thermoresistors on that membrane to define the very value of the
> calibration temperature.
> If anyone needs a measurement on a device, we would be glad to help
> out.
> Yours sincerely, Kai Hiltmann
> --
> mailto:Kai.Hiltmann@HSG-IMIT.de    http://www.HSG-IMIT.de
> K. Hiltmann; HSG-IMIT; Sensorics Section
> W.-Schickard-Str. 10; D-78052 Villingen-Schwenningen
> Phone ++49-7721-943-132; Fax ++49-7721-943-210
>
>