Browse Prior Art Database

Optical Alignment System for Probe, Pad Registration

IP.com Disclosure Number: IPCOM000121714D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 68K

Publishing Venue

IBM

Related People

Morgado, EJ: AUTHOR [+4]

Abstract

This article describes the use of a commercial optics and vision system to accomplish substrate registration.

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

Optical Alignment System for Probe, Pad Registration

      This article describes the use of a commercial optics and
vision system to accomplish substrate registration.

      A two-point probe tester is a machine which is made to inspect
the quality of multilayer substrates.  It performs this task by
moving two probes to a subset of pads on the substrate and analyzing
the quality of the substrate by performing measurements aimed at
isolating specific defects within the product under test.  In order
for these measurements to produce reliable results, the probes must
be placed at the center of the pads at anytime with an accuracy of a
few microns.

      The task of computing the relative orientation of the substrate
with the stages which carry the probes is done by registering each
probe with two specific pads on each substrate and computing the
coordinate transformation matrix of the x, y stages to which the
probes are attached and the substrate.  A combination of a machine
vision system and optics system is disclosed herein which performs
the registration automatically.  The optics system provides clear,
high resolution images from the substrate and the probes to the
vision system.

      Referring to Fig. 1, the optics system includes a TV micro
probe placed carefully in front of a front surface mirror.  The
mirror is made by applying aluminum coating to the hypotenuse of a
right angle prism. This facilitates the handling and rotation of the
mirror. ...