Reflective optical imaging system
US6014252A · kind A · utility
46Cited by
7References
15Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Feb 20, 1998 |
| Grant date | Jan 11, 2000 |
| Priority date | — |
| Expiry date | Feb 20, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S359/90
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical system compatible with short wavelength (extreme ultraviolet) radiation comprising four reflective elements for projecting a mask image onto a substrate. The four optical elements are characterized in order from object to image as convex, concave, convex and concave mirrors. The optical system is particularly suited for step and scan lithography methods. The invention increases the slit dimensions associated with ringfield scanning optics, improves wafer throughput and allows higher semiconductor device density.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.