{"schema_version":"1.0","canonical_url":"https://patentable.app/patents/US-9618387","patent":{"patent_number":"US-9618387","title":"Method for determining the phase angle and/or the thickness of a contamination layer at an optical element and EUV lithography apparatus","assignee":null,"inventors":[],"filing_date":"2015-07-24T00:00:00.000Z","publication_date":"2017-04-11T00:00:00.000Z","cpc_codes":["B82Y","G01N","G01N","G01N"],"num_claims":6,"abstract":"A method and associated EUV lithography apparatus for determining the phase angle at a free interface (17) of an optical element (13) provided with a multilayer coating (16) that reflects EUV radiation and/or for determining the thickness (d) of a contamination layer (26) formed on the multilayer coating (16). The multilayer coating (16) is irradiated with EUV radiation, a photocurrent (IP) generated during the irradiation is measured, and the phase angle at the free interface (17) and/or the thickness (d) of the contamination layer (26) is determined on the basis of a predefined relationship between the phase angle and/or the thickness (d) and the measured photocurrent (IP). The measured photocurrent (IP) is generated from the entire wavelength and angle-of-incidence distribution of the EUV radiation impinging on the multilayer coating (16)."},"analysis":{"summary":null,"layman_explanation":null,"technical_analysis":null,"business_analysis":null,"faqs":null,"topics":[],"tech_cluster":null},"seo":{"title":"Method for determining the phase angle and/or the thickness of a contamination layer at an optical element and EUV lithography apparatus","description":"A method and associated EUV lithography apparatus for determining the phase angle at a free interface (17) of an optical element (13) provided with a multilayer coating (16) that reflects EUV radiatio","keywords":[]},"attribution":{"source":"Patentable","source_url":"https://patentable.app","canonical_url":"https://patentable.app/patents/US-9618387","license":"CC-BY-4.0-like","license_terms":"AI-generated analysis on this page (summary, layman_explanation, technical_analysis, business_analysis, faqs) may be reused with attribution and a visible link back to the canonical URL above. Patent abstracts, claims, and bibliographic data are USPTO public domain.","required_link":"https://patentable.app/patents/US-9618387","citation_suggestion":"Patentable. \"Method for determining the phase angle and/or the thickness of a contamination layer at an optical element and EUV lithography apparatus\" (US-9618387). https://patentable.app/patents/US-9618387","copyright_holder":"Nomic Interactive Technology LLC"},"links":{"html":"https://patentable.app/patents/US-9618387","json":"https://patentable.app/api/llm-context/US-9618387","site":"https://patentable.app","llms_txt":"https://patentable.app/llms.txt"},"generated_at":"2026-06-06T06:22:11.737Z"}