System and method for finding the center of rotation of an R-theta stage
US6747746B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 2002 |
| Grant date | Jun 8, 2004 |
| Priority date | — |
| Expiry date | Aug 24, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/27
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical inspection system and method which uses a procedure for determining an offset between a field of view and a center or rotation of an R-theta stage, or polar coordinate stage. Determining this offset allows the precise location of a site being inspected on a wafer to be determined. The system and method take advantage of the fact that in a R-theta system there can be only two positions for the R-theta stage that will position a particular site under the lens of the imaging system of the optical inspection system. By moving the stage from a first position where a particular site is positioned in the field of view, to the second position where the particular site is positioned in the field of view, the offset can be determined.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.