Equipment and method for monitoring an immersion lithography device
US7714992B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 2006 |
| Grant date | May 11, 2010 |
| Priority date | — |
| Expiry date | Jun 1, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70341
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention concerns an equipment for monitoring an immersion lithography device provided with a main light source and a projection optics for printing images on a wafer. The propagating medium extending from the projection optics to the wafer consists of a liquid (3). The equipment comprises: a chamber (51) for receiving at least part of said liquid (3), a diffraction grating (50) immersed in the chamber; a secondary light source (271) for emitting a secondary incident beam (20) towards the grating so as to obtain a diffracted beam; angle measuring members (57) capable of measuring at least one diffraction angle corresponding to a maximum intensity of an order of diffraction of the beam diffracted by the grating (500), and computing means (505) for calculating an estimate of a physical quantity concerning the refractive index of the liquid.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.