Tim,

A "quick and dirty", non-destructive way as sugested by my test engineer is
to use a thin thermocouple (i.e. 2 x 0,2mm.) and esentially slide it under
the BGA.  This is not the most robust way because you will get some
temperature error (i.e. you are not measuring the solder joints themselves,
just the surrounding air under the chip.)

If you can afford to scarp a sample of product I would suggest going with
Jerry's approach which would be more robust for the accuracy of the
measurement.  Hope this has helped.

Doug Bennett
Sales Engineer
Heraeus Amersil, Inc.
Atlanta, Georgia USA
770-623-5630 ext 4225
[log in to unmask]





At 04:56 PM 1/26/98 -0500, you wrote:
>Where should I place my thermocouples to determine the best oven profile
>for assemblies having BGAs since their leads aren't reachable, and how
>should I attach them?
>
>Thanks
>
>Tim Stammely
>Manufacturing Services & Integration (MSI)
>
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