Self-cleaning optic for extreme ultraviolet lithography
US6664554B2 · kind B2 · utility
19Cited by
8References
18Claims
0Family size
Assignee
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Key dates
| Filing date | Jan 3, 2001 |
| Grant date | Dec 16, 2003 |
| Priority date | — |
| Expiry date | Sep 13, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG21K2201/067
- WIPO fieldMicro-structural and nano-technology
- WIPO sectorChemistry
Abstract
A multilayer reflective optic or mirror for lithographic applications, and particularly extreme ultraviolet (EUV) lithography, having a surface or “capping” layer which in combination with incident radiation and gaseous molecular species such as O2, H2, H2O provides for continuous cleaning of carbon deposits from the optic surface. The metal capping layer is required to be oxidation resistant and capable of transmitting at least 90% of incident EUV radiation. Materials for the capping layer include Ru, Rh, Pd, Ir, Pt and Au and combinations thereof.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.