Wavefront-aberration-measuring device and exposure apparatus
US8351050B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 6, 2010 |
| Grant date | Jan 8, 2013 |
| Priority date | — |
| Expiry date | Apr 12, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J9/0215
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A wavefront-aberration-measuring device measures wavefront aberration of a to-be-tested optical system and includes a diffraction grating that splits light transmitted through the optical system, a detecting unit that detects interference fringes produced by beams of the split light, an arithmetic unit that calculates the wavefront aberration from the detected interference fringes, an image-side mask insertable into and retractable from an image plane of the optical system, and an illuminating unit that incoherently illuminates the image-side mask. The image-side mask has an aperture with a diameter larger than λ/2NA, where λ denotes a wavelength of the illuminating unit and NA denotes a numerical aperture of the to-be-tested optical system. The arithmetic unit calculates the wavefront aberration of the optical system from the interference fringes detected with the image-side mask being retracted from the image plane and the interference fringes detected with the image-side mask being in the image plane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.