Extreme ultraviolet lithography reflective mask
US6159643A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 1, 1999 |
| Grant date | Dec 12, 2000 |
| Priority date | — |
| Expiry date | Mar 1, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/24
- WIPO fieldMicro-structural and nano-technology
- WIPO sectorChemistry
Abstract
A reflective lithography mask (12) includes a pattern-producing portion (200) and a substrate (300) supporting the pattern-producing portion on its top surface. The pattern-producing portion has reflective regions and non-reflective regions corresponding to a desired circuit pattern. The substrate (300) comprises a top layer (306) having a top surface with an optical flatness in the range of at least a quarter-wavelength and a bottom layer (304) having a coefficient of thermal expansion less than about 1.0 ppm/.degree. C. The reflective mask (12) is used in a lithography method to delineate a latent image of a desired circuit pattern (preferably having design rules of 0.18 .mu.m and less) onto a wafer (14) by illuminating the mask (12) with radiation (preferably having a wavelength of 3 nm to 50 nm) so as to reflect radiation from the reflective regions of the mask onto the wafer (14).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.