Six-degree-of-freedom displacement measurement method for exposure region on silicon wafer stage
US9995569B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Mar 15, 2016 |
| Grant date | Jun 12, 2018 |
| Priority date | — |
| Expiry date | Mar 15, 2036 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/38
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A six-degree-of-freedom displacement measurement method for an exposure region on a wafer stage, the wafer stage comprises a coil array and a movable platform. A planar grating is fixed below a permanent magnet array of the movable platform. A reading head is fixed in a gap of the coil array. A measurement region is formed on the planar grating by an incident measurement light beam of the reading head. The reading head measures the six-degree-of-freedom displacement of the measurement region, so that the six-degree-of-freedom displacement of the exposure region is obtained through calculation. In the method, the six-degree-of-freedom displacement of the exposure region at any time is measured; the measurement complexity is reduced and the measurement precision is improved, and especially, the six-degree-of-freedom displacement of the exposure region can be precisely measured at any time even if the movable platform has high flexibility.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.