Variable numerical aperture large-field unit-magnification projection system
US6813098B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 2, 2003 |
| Grant date | Nov 2, 2004 |
| Priority date | — |
| Expiry date | Mar 27, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70225
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical system for projection photolithography is disclosed. The optical system is a modified Dyson system capable of imaging a large field over both a narrow and a broad spectral range. The optical system includes a positive lens group having a positive subgroup of elements that includes at least a plano-convex element and a negative subgroup that includes at least a negative meniscus element. The lens subgroups are separated by a small air space. The positive and negative subgroups constitute a main lens group arranged adjacent to but spaced apart from a concave mirror along the mirror axis. The system also includes a variable aperture stop so that the system has a variable NA. A projection photolithography system that employs the optical system is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.