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US 12,111,578 B2Granted
Mirror for an illumination optical unit of a projection exposure apparatus comprising a spectral filter in the form of a grating structure and method for producing a spectral filter in the form of a grating structure on a mirror
AssigneeCarl Zeiss SMT GmbH
InventorsChristof Jalics, Fabian Schuster, Holger Kierey, Andreas Sandner, Tobias Meisch
Life of this patent
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Abstract
A mirror for an illumination optical unit of a projection exposure apparatus comprises a spectral filter in the form of a grating structure, wherein the grating structure has a maximum edge steepness in the range of 15° to 60°.
Claims24
A mirror, comprising:
- a reflection surface comprising a spectral filter which comprises a grating structure,
- wherein:
- the grating structure comprises a plurality of grating ridges;
- for each grating ridge, the grating ridges comprises a front side and sidewalls;
- for each of at least some pairs of adjacent grating ridges:
- a groove comprising a bottom is between the adjacent grating ridges;
- a depth of the groove is a distance between the bottom and the adjacent grating ridges;
- and
- the depth is configured to mask out infrared radiation;
- the grating structure has a maximum edge steepness in the range of 15° to 60°;
- and
- the mirror is selected from the group consisting of a condenser mirror and a collector mirror.
9 more elements
A method, comprising:
- structuring a structuring layer applied on a substrate of a mirror body;
- and
- structuring the substrate of the mirror body,
- wherein structuring the substrate of the mirror body comprises at least one member selected from the group consisting of:
- etching with an etching angle in the range of 0° to 60°;
- etching, wherein the structuring layer and the substrate of the mirror body have different etching rates;
- and
- etching, wherein the structuring layer is provided with a sidewall steepness in the range of 10° to 90° during the structuring;
- and
- applying a closed protective layer on the substrate,
- wherein:
- the grating structure comprises a plurality of grating ridges;
- for each grating ridge, the grating ridges comprises a front side and sidewalls;
- for each of at least some pairs of adjacent grating ridges:
- a groove comprising a bottom is between the adjacent grating ridges;
- a depth of the groove is a distance between the bottom and the adjacent grating ridges;
- and
- the depth of the groove is configured to mask out infrared radiation;
- and
- the grating structure has a maximum edge steepness in the range of 15° to 60°.
17 more elements
Dependencies are inferred from the claim text.