Browse Prior Art Database

Simplified Automated Wafer Orientor and Notch Finder

IP.com Disclosure Number: IPCOM000037361D
Original Publication Date: 1989-Dec-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 4 page(s) / 139K

Publishing Venue

IBM

Related People

Bancroft, CE: AUTHOR [+5]

Abstract

This article describes an orientor mechanism to rapidly center a wafer and then locate its notch.

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Simplified Automated Wafer Orientor and Notch Finder

This article describes an orientor mechanism to rapidly center a wafer and then locate its notch.

Typically, if a three-point algorithm were used with a current two-fiber-optic- sensor system, it would take many more mechanical motions to center a wafer in a measurement and inspection mechanism. The X stage would have to be moved to find the edge for one point. Then the theta stage would advance the wafer to the next point. This would have to be repeated for all three points. All these motions are time consuming, add to the wear on the system, and provide opportunities for failure. The simplified orientor mechanism disclosed herein is able to locate the edges at three points simultaneously with no motions. It also is able to handle many different wafer sizes.

(Image Omitted)

Fig. 1 is a top view of the mechanism of this disclosure. Figs. 2 and 3 are front and side views, respectively. In operation, when a wafer 2 is placed in the orientor mechanism it will be resting on top of three charge-coupled device (CCD) linear sensors 1. The part of each sensor that is covered by the wafer will produce a series of low level values. The part of the sensor that is not covered by the wafer will produce a series of high level values. Therefore, the edge of the wafer can be located by looking for the light to dark transition. The three sensors will determine three known points on the perimeter of the wafer. With three known p...