Mark,

There is a device produced by EV Group (whom I represent) called an EVG40, which
is specifically designed to measure front to back overlay.

The system utilizes top and bottom microscopes with a calibrated optical axis to
perform the measurements.  The system features software that shows the top and
bottom alignment keys simultaneously via a splitfield display, and will
automatically perform the calculations necessary to determine top to bottom
overlay.

If you have any further questions, please contact me.  My contact information is
shown below.

Best Regards,

Chad Brubaker



EV Group-Technology, Tel: (602) 437 9492 x 119, Fax: (602) 437 9435
E-mail: [email protected],  Web: www.EVGroup.com,

 -----Original Message-----
From:   Mark van der Heijden [mailto:[email protected]]
Sent:   Wednesday, March 19, 2003 6:32 AM
To:     [email protected]
Subject:        [mems-talk] Overlay between front and back of wafer


Hi All,

Does anyone know of a method/device to measure which i can use to measure
the overlay between structures on the front and the back of a wafer.

Thanks,
Mark




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