Browse Prior Art Database

Optical Alignment Method to Insure Accurate Sizing of Patterned Substrates

IP.com Disclosure Number: IPCOM000103102D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 47K

Publishing Venue

IBM

Related People

Fertile, FF: AUTHOR [+2]

Abstract

Disclosed is an optical method utilizing 4 (four) video cameras, 3 (three) screen splitters, a video memory and monitor to achieve a very accurate alignment of patterned substrates for sizing with respect to the substrate pattern.

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Optical Alignment Method to Insure Accurate Sizing of Patterned Substrates

      Disclosed is an optical method utilizing 4 (four) video
cameras, 3 (three) screen splitters, a video memory and monitor to
achieve a very accurate alignment of patterned substrates for sizing
with respect to the substrate pattern.

      This alignment system uses 4 video cameras which are focused on
4 pattern fiducials on the substrate (one in each quadrant).  By the
use of 3 screen splitters, all 4 fiducials can be displayed on the
monitor simultaneously for ease of operator viewing.  The system is
calibrated by placing an aligned substrate or glass master under the
cameras.  The output image is then stored in a video memory for
utilization later.

      To align a substrate, an operator places a substrate under the
4 cameras.  The output is then observed at the monitor which displays
both the stored image and the live substrate image simultaneously.
While viewing the monitor, the operator adjusts the position of the
substrate until the live image completely overlays the stored image.
Using switchable electronics, the operator can reverse light
polarities and adjust contrast to enhance the view.

      This system can also be utilized to compare differences between
identical parts utilizing electronics instead of eyes.  To do so, a
standard part is placed under the camera or cameras.  The image is
then stored into the video memory. The part to be compared is then
placed...