Browse Prior Art Database

Dicing Alignment Targets for Use with Pattern Recognition System

IP.com Disclosure Number: IPCOM000109430D
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 1 page(s) / 49K

Publishing Venue

IBM

Related People

Beatty, CT: AUTHOR

Abstract

After processing of semiconductor wafers is complete, the wafers are diced with a diamond-tipped saw into individual chips. In the past, large amounts of time were spent for unique patterns in the chip image to perform automatic alignment of the wafers. If an acceptable pattern could not be located, a manual alignment would be required.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 95% of the total text.

Dicing Alignment Targets for Use with Pattern Recognition System

      After processing of semiconductor wafers is complete, the
wafers are diced with a diamond-tipped saw into individual chips.  In
the past, large amounts of time were spent for unique patterns in the
chip image to perform automatic alignment of the wafers.  If an
acceptable pattern could not be located, a manual alignment would be
required.

      A pattern recognition system would be a useful means to provide
automatic alignment of the wafers.  However, most chip images are too
intricate for pattern recognition systems to identify due the high
density of the structures.  A pattern recognition system requires a
few bold and distinctive patterns which stand out uniquely.  While
large visual alignment targets exist in the kerf, these visual
targets are symmetrical, i.e., not unique, and are marginally useful
for a pattern recognition system.

      This article suggests the addition of new visual targets to the
kerf areas which will be useful for alignment for pattern recognition
system.  Adding simple nonelectrical or functional metal shapes to
the kerf area for the purposes of alignment of the dicing saw, will
require no additional space in the chip image because the shape is
added outside the chip image boundary.  The asymmetrical shape of the
target provides a unique alignment point, as compared to a standard
visual target.  The accompanying figure depicts two suitable targets
for pat...