EUV collector mirror
AssigneesCarl Zeiss SMT GmbH, ASML Netherlands B.V.
InventorMarcus Van De Kerkhof
Life of this patent
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Abstract
An EUV collector mirror has a reflection surface (16) to reflect usable EUV light which impinges on the reflection surface (16) from a source region (17) to a subsequent EUV optics. The reflection surface (16) carries a pump light grating structure (19) configured to retroreflect pump light (22) which impinges upon the pump light grating structure (19) from the source region (17) back to the source region (17). The pump light (22) has a wavelength deviating from the wavelength of the usable EUV light. Such EUV collector mirror enables a high conversion efficiency between the energy of pump light of a laser discharged produced plasma (LDPP) EUV light source on the one hand and the resulting usable EUV energy on the other.
Claims12
Collector mirror configured for extreme ultraviolet (EUV) light, comprising:
- a reflection surface to reflect usable EUV light which impinges on the reflection surface from a source region to a subsequent EUV optics,
- wherein the reflection surface carries a pump light grating structure configured to retroreflect pump light which impinges upon the pump light grating structure from the source region back to the source region, the pump light having a wavelength (λPL) deviating from the wavelength of the usable EUV light, and
- wherein a pitch of the pump light grating structure varies over the reflection surface of the EUV collector mirror.
Dependencies are inferred from the claim text.