Reflective projection system comprising four spherical mirrors
US5410434A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 9, 1993 |
| Grant date | Apr 25, 1995 |
| Priority date | — |
| Expiry date | Sep 9, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B17/0657
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The reflective projection system has a relatively wide field of view that comprises two concave and two convex spherical mirrors, situated in certain non-light-blocking positions with respect to one another, for deriving, with negligible image aberrations, a projected magnified or demagnified image over at least one of a range of magnification or demagnification power values between 3 and infinity that may be zoomed over this range. Such a reflective projection system, utilizing a high-power excimer laser radiation source, may be employed for ablating the surface of a substrate, such as the surface of the coating of a coated wafer, with a demagnified image of an object pattern defined by a mask, the radiation intensity of the demagnified image being sufficiently high to effect this ablation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.