Alignment apparatus
US6025688A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 9, 1996 |
| Grant date | Feb 15, 2000 |
| Priority date | — |
| Expiry date | Apr 9, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B2219/41212
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An apparatus for moving a stage, supported by a base, to a target position. The apparatus includes a motor for driving the stage in X and Y directions, a laser interferometer for measuring a current position of the stage in the X and Y directions and a controller for generating a control signal for controlling the motor to move the stage to the target position in the X and Y directions on the basis of the target position and for dynamically setting a transfer function associated with generation of the control signal in correspondence with the current measured position. The controller sets the transfer function so that a gain decreases as the stage moves toward a peripheral portion of the base.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.