The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 09, 1999
Filed:
May. 07, 1996
John M Rush, Mountain View, CA (US);
J Randolph Andrews, Campbell, CA (US);
Richard Collins, San Jose, CA (US);
Conor Patrick O'Carroll, Sunnyvale, CA (US);
David Ou, Mountain View, CA (US);
Fortrend Engineering Corporation, Sunnyvale, CA (US);
Abstract
A wafer sorting system utilizing optical character recognition and optical 'gate sensors' to determine the orientation of the wafers for prealigning. It is envisioned that the machine will be installed in conjunction with a computer controller and multiple cassette stations. A first end of a transfer arm of a robot is equipped with an end effector to transfer individual wafers. The end effector of the transfer arm is extendable and retractable to select and remove the desired wafer from its cassette, and to transfer it to the prealigner or a target cassette in its proper orientation. The end effector includes a vacuum pickup and a sensor that enables detection of presence or absence of wafers in the cassette, and any misaligned wafers in the cassette. Further gate sensors are mounted on the prealigner to accomplish the orientation function prior to the wafer being placed on the prealigner chuck. Multiple perimeter points are used to determine the position of the center of the wafer. The optical character recognition capability of the system then allows the individual wafers to be identified and to be sorted as desired.