On the fly center-finding during substrate handling in a processing system
US6198976A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 4, 1998 |
| Grant date | Mar 6, 2001 |
| Priority date | — |
| Expiry date | Mar 4, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B2219/50151
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A substrate center-finding method and apparatus, for determining the center of a substrate being passed through a substrate handling chamber of a substrate processing system, includes any number of sensors arranged in any configuration and permits the substrate to pass through any trajectory that triggers the sensors. The locations of the sensors are calibrated by homing in on the sensors using a point, the reference point, near the tip of an arm assembly on a substrate handler. The substrate handler has an encoder for sensing the pivot angles of links in the arm assembly, whereby the coordinates of the reference point can be calculated from the angles and lengths of the links. When the substrate triggers a sensor, the location of the reference point is again calculated, and the coordinates of the trigger point on the edge of the substrate is determined relative to the reference point. A suitable number of trigger points on the edge of a circular substrate will define a circle, so the center of the circle can be calculated, and the location of the substrate can be adjusted to account for any offset from the reference point.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.