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:
Apr. 14, 1998
Filed:
Sep. 30, 1996
Lloyd M Berken, Fremont, CA (US);
Frederik W Freerks, Cupertino, CA (US);
William H Jarvi, San Jose, CA (US);
Hatice Sahin, Cupertino, CA (US);
Applied Materials, Inc., Santa Clara, CA (US);
Abstract
A wafer positioning system determines the position of a wafer during processing by monitoring the position of the wafer transport robot as the robot transports the wafer by one or more position sensors. The wafer positioning system incorporates a transparent cover on the surface of the wafer handling chamber and two optical position sensors disposed on the surface of the transparent cover. The position sensors direct light through the wafer handling chamber to reflectors near the floor of the chamber which reflect the light back to the position sensors. A detector within the position sensor detects when the beam path from the position sensor to the reflector is uninterrupted. As wafers are transported through the chamber, the edge of the transported wafer interrupts the position sensor beam path causing the output of the position sensor to switch states. When the position sensor output switches, the position of the wafer transport robot is measured. At least two data points are measured to establish the wafer position. If the wafer is not at its nominal position, the position of the wafer transport robot is adjusted to compensate for the wafer misalignment.