Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Edge Inspection of Semiconductor Substrates

IP.com Disclosure Number: IPCOM000101938D
Original Publication Date: 1990-Sep-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 3 page(s) / 72K

Publishing Venue

IBM

Related People

Mathisen, ES: AUTHOR

Abstract

A technique is described whereby the edges of semiconductor substrates can be rapidly inspected. The concept is based on grid-coding techniques and incorporates unique optical Fourier filtering and compression for processing data.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 65% of the total text.

Edge Inspection of Semiconductor Substrates

       A technique is described whereby the edges of
semiconductor substrates can be rapidly inspected.  The concept is
based on grid-coding techniques and incorporates unique optical
Fourier filtering and compression for processing data.

      Frequently, semiconductor substrates, chips and similar devices
require inspections of potential damage caused by dicing operations
and handling.  The concept described herein provides a rapid
procedure for inspecting the edges and provides input for optical
data processing.

      Figs. 1 and 2 illustrate how substrate 10 is moved and oriented
within a test station so that light sources 11 and 12 can project
through gratings 13 and 14, through lens 15 and 16 to the edges of
substrate 10.  Four mirrors 17 (A, B, C and D) are positioned at
forty-five degree angles so as to direct four side views into two
closed circuit TV (CCTV) units 18 through beam splitters 19 and shown
in Fig. 3.

      CCTV units 18 are oriented at ninety degrees to each other
having horizontal scan lines parallel to the sides and contain
anamorphic optics, prisms or cylindrical lenses, which compress the
horizontal dimension (length of the sides) to fit the TV frame.  The
video signals are mixed in mixer unit 20, as shown in Fig. 4, or are
multiplexed to produce a composite picture 21 on liquid crystal TV
(LCTV) monitor 22.  The views of the sides are interlaced by the
fixed displacement of the t...