Optical member, method of manufacturing the same, and projection exposure system
US7166163B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 27, 2004 |
| Grant date | Jan 23, 2007 |
| Priority date | — |
| Expiry date | Mar 18, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70958
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of manufacturing an optical member includes a crystal growing step and a carving step. The crystal growing step includes melting a mixture of fluoride powder and a scavenger at a melting temperature of a melting point for the fluoride and above, and then crystallizing the melted fluid and further cooling down an obtained fluoride crystal in a temperature range from 1000° C. to 900° C. by a temperature decreasing rate in a range from 0.1 to 5° C./hr. The carving step includes carving an optical member out of the fluoride crystal obtained in the crystal growing step such that the optical member is made of a fluoride crystal in which a maximum diameter dmax of scattering bodies existing internally and a quantity ns of the scattering bodies per 1 cm3 satisfy a condition represented by the following formula (1):0<dmax2×ns<6.5×10−4(cm−1). (1)
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.