Zoom illumination system for use in photolithography
US6307682A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 16, 2000 |
| Grant date | Oct 23, 2001 |
| Priority date | — |
| Expiry date | Feb 16, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70075
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The present invention provides an illumination system for varying the size of an illumination field incident to a scattering optical element. The illumination field is subsequently imaged to a reticle in a photolithographic process. The illumination system includes, in series along an optical axis of the illumination system, an optical source, a beam conditioner, a first optical integrator, a first or input collimating lens, a zoom array integrator (ZAI), a second or output collimating lens, the optical scattering element, a relay lens, and the reticle. The ZAI includes an assembly of fixed and moveable lens components arranged to vary the size of the illumination field throughout a zoom range of the ZAI while maintaining telecentric illumination at a substantially fixed numerical aperture. Illumination telecentricity and substantially fixed numerical apertures are maintained at both the scattering optical element and the reticle throughout the zoom range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.