Patent ID: 11971656
Assignee: ASML NETHERLANDS B.V.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 20:
21. A membrane assembly comprising:
a hollow structure arranged to be located in a path of radiation such that the radiation can pass through the hollow structure; and
a membrane arranged to at least partially span the hollow structure and through which radiation is arranged to pass, the membrane comprising:
a membrane layer comprising silicon; and
a capping layer comprising at least one selected from: Ru, Zr, Mo, a silicon oxide, a zirconium oxide, an aluminum oxide, boron nitride, a ruthenium oxide, a ruthenium nitride, a zirconium nitride, a molybdenum oxide, a molybdenum nitride or a molybdenum silicide,
wherein 1) the membrane layer is configured to transmit at least 80% of incident EUV radiation, and the capping layer has a thickness of at least 1 nm and at most 10 nm, or 2) the material for the capping layer has a tensile stress of 300 MPa or lower, and the capping layer has a thickness of at least 1 nm and at most 10 nm.