Browse Prior Art Database

High Speed Disk Scanner for Ion Implantation

IP.com Disclosure Number: IPCOM000086241D
Original Publication Date: 1976-Aug-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Balderes, D: AUTHOR [+3]

Abstract

U. S. Patent 3,778,626 discloses apparatus for mechanically scanning wafers during ion implantation, in which the contact is rotated and transversed with respect to the beam.

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High Speed Disk Scanner for Ion Implantation

U. S. Patent 3,778,626 discloses apparatus for mechanically scanning wafers during ion implantation, in which the contact is rotated and transversed with respect to the beam.

The present scan apparatus offers means for efficiently effecting high-speed mechanical scanning involving rotational and transverse motions. Using this mechanical scan system, high-uniform (within + or - 1-2%) implants are obtained by rapidly rotating (2000 RPM) semiconductor wafers attached to a disk, located in high vacuum, in the path of a stationary impinging ion beam.

To provide complete coverage of the wafer by the narrow beam, the target disk is simultaneously moved transversely at a controlled low velocity. The beam pattern on the target disk consists of a fine pitch overlapping spiral resulting in a uniform illumination of the wafer by the ion beam.

The high-speed scanner assembly consists of a target disk 1 containing appropriate clamping devices for semiconductor wafers 2 and a high-speed motor 3. The high-speed scanner assembly is mounted to a housing 4 guided on bearings 5 and capable of being driven in the vertical direction.

To compensate for the tangential velocity gradient resulting when a spinning wafer is transversed through a stationary beam 6, the transverse velocity "v" is varied inversely proportional to the effective radius "R" of the beam to the center of the axis of spin, i.e., v = k/R. This is accomplished via a continu...