Reflective mask blank, reflective mask and methods of producing the mask blank and the mask
US7981573B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 7, 2008 |
| Grant date | Jul 19, 2011 |
| Priority date | — |
| Expiry date | Apr 6, 2029 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31616
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A reflective mask blank has a substrate (11) on which a reflective layer (12) for reflecting exposure light in a short-wavelength region including an extreme ultraviolet region and an absorber layer (16) for absorbing the exposure light are successively formed. The absorber layer (16) has an at least two-layer structure including as a lower layer an exposure light absorbing layer (14) formed by an absorber for the exposure light in the short-wavelength region including the extreme ultraviolet region and as an upper layer a low-reflectivity layer (15) formed by an absorber for inspection light used in inspection of a mask pattern. The upper layer is made of a material containing tantalum (Ta), boron (B), and nitrogen (N). The content of B is 5 at % to 30 at %. The ratio of Ta and N (Ta:N) falls within a range of 8:1 to 2:7. Alternatively, the reflective mask blank has a substrate on which a multilayer reflective film and an absorber layer are successively formed. In this case, the absorber layer is made of a material containing tantalum (Ta), boron (B), and nitrogen (N). The content of B is 5 at % to 25 at %. The ratio of Ta and N (Ta:N) falls within a range of 8:1 to 2:7.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.