Browse Prior Art Database

Positioner Vacuum Stop

IP.com Disclosure Number: IPCOM000084824D
Original Publication Date: 1976-Jan-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Anderson, WT: AUTHOR [+2]

Abstract

Described is an automatic shuttle valve which is used as a vacuum brake and stop, for positioning wafers on rising vacuum chucks and transports.

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Positioner Vacuum Stop

Described is an automatic shuttle valve which is used as a vacuum brake and stop, for positioning wafers on rising vacuum chucks and transports.

In a conventional system, two vacuum ports are used in an air track pavement to stop and hold the wafer. When Z (vertical) motions are required, a vacuum hole in the rising chuck is activated, which turns off the two braking ports in the pavement. During this transition, the wafer shifts or changes position, which is undesirable.

This scheme uses a sliding insert in the vacuum ports and the vacuum is left on continuously. As Z motion occurs, that is the vacuum chuck rises (Fig. 1), the vacuum causes the insert to follow the wafer (Fig. 2).

The insert is cross-drilled so that after rising a predetermined amount, the vacuum is broken by air leakage. The insert falls away by gravity (Fig. 3).

This assures precise location of the wafer over the vacuum ports until the wafer has become firmly seated on the rising chuck, yet introduces no stress on the wafer as the vacuum is broken.

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