Reflective optical element for EUV lithography
US8937709B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 22, 2011 |
| Grant date | Jan 20, 2015 |
| Priority date | — |
| Expiry date | Oct 17, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70958
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A stress-reduced reflective optical element for a working wavelength in the soft X-ray and extreme ultraviolet wavelength range includes a first multilayer system (4) of at least two alternating materials (41, 42) having different real parts of the refractive index at the working wavelength on a substrate (2), which exerts a layer stress on the substrate (2), and comprising a second multilayer system (6) of at least two alternating materials (61, 62) on a substrate (2), which exerts an opposed layer stress on the substrate (2) and is arranged between the first multilayer system (4) and the substrate (2), wherein a first (61) of the at least two materials of the second multilayer system (6) is interrupted by layers (62) having a thickness of up to 1 nm of the at least one further material of the second multilayer system (6) at such distances that the first material is present in an amorphous state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.