Method and apparatus for modifying a substrate surface of a photolithographic mask
AssigneesCarl Zeiss SMT GmbH, Carl Zeiss SMS GmbH
InventorsSergey Oshemkov, Ralph Klaesges, Markus Mengel
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Abstract
Disclosed is a method of modifying of a surface of a substrate of a photolithographic mask for extreme ultraviolet radiation comprising the step of focusing femtosecond light pulses of a laser system onto the substrate so that a plurality of color centers is generated inside the substrate, wherein the color centers are distributed to cause a modification of the substrate surface.
Claims17
1-82. (canceled)
A method of modifying a surface of a substrate of a photolithographic mask for extreme ultraviolet radiation, the method comprising the step of:
- focusing femtosecond light pulses of a laser system onto the substrate so that a plurality of color centers is generated inside the substrate, wherein the color centers are distributed to cause a modification of the substrate surface.
A method for correcting a substrate surface of a photolithographic mask for extreme ultraviolet radiation, comprising the steps of:
- a. analyzing the substrate surface;
- b. focusing light pulses of a laser system onto positions in the substrate where the substrate height is below a predetermined substrate height so that energy exceeding a threshold of optical breakdown is deposited at these positions;
- and
- c. focusing femtosecond light pulses of the laser system onto positions in the substrate where the substrate height exceeds the predetermined substrate height so that a plurality of color centers are generated at these positions.
An apparatus for modification of at least a portion of a substrate surface of a photolithographic mask for extreme ultraviolet radiation, comprising:
- a. at least one light source for generating light pulses of variable pulse duration, repetition rate and energy;
- b. at least one objective for focusing light pulses of a light beam;
- and
- c. at least one scanning unit for scanning the light beam across the substrate surface, wherein the pulse duration, the repetition rate, the energy and/or the focusing are selected such that color centers are generated in the portion of the substrate.
A minor for extreme ultraviolet radiation, comprising:
- a. at least one substrate having at least one multi-layer structure on a first side;
- and
- b. at least one transparent conductive coating on a second side of the substrate opposite to the first side.
A photolithographic mask for extreme ultraviolet radiation, comprising:
- a. at least one substrate having at least one multi-layer structure and at least one absorbing structure on a first side;
- and
- b. at least one transparent conductive coating on a second side of the substrate opposite to the first side.
An apparatus for modification of at least a portion of a substrate surface of a photolithographic mask for extreme ultraviolet radiation, comprising:
- a. means for generating light pulses of variable pulse duration, repetition rate and energy;
- b. means for directing and focusing light pulses of a light beam;
- c. means for scanning the light beam across the substrate surface, wherein the pulse duration, the repetition rate, the energy and the focusing are selected such that color centers are generated in the portion of the substrate.
Dependencies are inferred from the claim text.