Extreme ultraviolet photolithography mask, with absorbent cavities
US7781128B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 23, 2006 |
| Grant date | Aug 24, 2010 |
| Priority date | — |
| Expiry date | Mar 23, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/24
- WIPO fieldMicro-structural and nano-technology
- WIPO sectorChemistry
Abstract
The invention relates to extreme ultraviolet photolithography masks operating in reflection. These masks comprise a lower mirror (22) covering a substrate (20), and absorbent zones formed on the lower mirror in an etched pattern that defines the pattern to be reproduced. According to the invention, the absorbent zones are formed by resonant Fabry-Pérot cavities exhibiting a strong absorption peak for the operating wavelength. The cavities are formed by the lower mirror (22), an upper mirror (24) and, between the mirrors, a transparent medium, the thickness of which is calculated so as to produce an absorption peak at the operating wavelength. The medium may be formed from silicon (27) or by a superposition of a thin silicon oxide layer (forming a buffer layer to facilitate etching) and a silicon layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.