Lens system for X-ray projection lithography camera
US5353322A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 20, 1993 |
| Grant date | Oct 4, 1994 |
| Priority date | — |
| Expiry date | May 20, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70233
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Optimum solutions for three-mirror lenses for projection lithography cameras using X-ray radiation to image a mask on a wafer are represented as single points within regions of two-dimensional magnification space defined by the magnification of a convex mirror as one coordinate and the ratio of the magnifications of a pair of concave mirrors optically on opposite sides of the convex mirror as another coordinate. Lenses within region 30, 50, and preferably within region 40, 60, of such magnification space represent potential solutions that are optimizable by standard computer optical design programs and techniques to achieve extremely low distortion lenses having a resolution of about 0.1 micron or less. Two of these lens systems having large chief ray angles at the mask and chief rays inclined away from the optical axis of the lens system in a direction from the source toward the mask are described in more detail.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.