Browse Prior Art Database

Fail Safe Detection for Wafer Handling Using Reflected Light Beam

IP.com Disclosure Number: IPCOM000084776D
Original Publication Date: 1976-Jan-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Raacke, KH: AUTHOR

Abstract

In the operation of fluidic transportation means, especially for automated semiconductor production wherein wafers are either randomly or sequentially conveyed to and from processing units, it is believed necessary to have fail-safe arrangements at such locations in the system as intersections, buffers, turnaround means and processing by pass options.

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Fail Safe Detection for Wafer Handling Using Reflected Light Beam

In the operation of fluidic transportation means, especially for automated semiconductor production wherein wafers are either randomly or sequentially conveyed to and from processing units, it is believed necessary to have fail-safe arrangements at such locations in the system as intersections, buffers, turnaround means and processing by pass options.

This is accomplished through the coordinated use of stops or similar means, and air jets controlled by a light source and sensing means incorporated within the section being controlled.

Fig. 1 is a schemetic illustration of a light source 1 and a sensing means 2. Light is passed through the light pipe 3 or similar means in a dual-plenum arrangement shown by 4 and 5. The wafer 6 passing through an intersection or any other arrangement interrupts the light flow to the sensing means 2 and where vacuum stops, not shown, are utilized to stop a workpiece, the vacuum is terminated and air jets used to direct or center the wafer 6 in the desired configuration is activated.

The light interruption also maintains the area in an occupied or busy condition, whereby proper programming will prevent other wafers from entering the section and causing "pile ups". As the wafer 6 leaves the area and light continues to flow, the sensor 2 initiates the program to allow other wafers to enter the area as well as reactivating the vacuum stops to maintain the section in a hold...