Browse Prior Art Database

Sensing Registration Switch

IP.com Disclosure Number: IPCOM000078532D
Original Publication Date: 1973-Jan-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Buechele, JW: AUTHOR [+2]

Abstract

A wafer sensing registration system uses a pair of sensing locations and a single sensor.

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Sensing Registration Switch

A wafer sensing registration system uses a pair of sensing locations and a single sensor.

Wafer holder 1 (Fig. 1) has a pair of force fingers 2 and a centering pin 3. Sensing orifices 4 and 5 on each side of pin 3 are connected to a common source of air under pressure through channel 6. The three conditions of the device are shown in Figs. 2A, B and C. With no wafer present, the air escapes to the atmosphere (Fig. 2A). With wafer 7 improperly registered (Fig. 2B), air still escapes from one orifice 4 and the sensor 8 does not actuate and turn off the positioning device, not shown. With wafer 7 properly registered (Fig. 2C), orifices 4 and 5 are closed to the atmosphere and the air pressure through line 9 is sufficient to cause sensor 8 to turn off the positioning device.

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