Crystal manufacture method
AssigneeCanon Kabushiki Kaisha
InventorKentaro Doguchi
Life of this patent
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Abstract
A method for manufacturing fluoride crystal includes the steps of adding scavenger and a material to a crucible, melting the scavenger and material at a temperature higher than a melting point so that a ratio of a thickness of the fluoride crystal that has been melted to an inner diameter of the crucible may be 0.2 or higher, and gradually crystallizing and purifying the material.
Claims10
A method for manufacturing fluoride crystal comprising the steps of:
- adding scavenger and a material to a crucible;
- melting the scavenger and material at a temperature higher than a melting point so that a ratio of a thickness of the fluoride crystal that has been melted to an inner diameter of the crucible may be 0.2 or higher;
- and
- gradually crystallizing and purifying the material.
An optical element made of fluoride crystal, said fluoride crystal being manufactured by a method including the steps of adding scavenger and a material to a crucible, melting the scavenger and material at a temperature higher than a melting point so that a ratio of a thickness of the fluoride crystal that has been melted to an inner diameter of the crucible may be 0.2 or higher, and gradually crystallizing and purifying the material.
An exposure apparatus comprising an optical system including an optical element made of fluoride crystal, said fluoride crystal being manufactured by a method including the steps of adding scavenger and a material to a crucible, melting the scavenger and material at a temperature higher than a melting point so that a ratio of a thickness of the fluoride crystal that has been melted to an inner diameter of the crucible may be 0.2 or higher, and gradually crystallizing and purifying the material.
A device fabrication method comprising the steps of:
- exposing an object using an exposure apparatus;
- and
- performing a predetermined process for the exposed object, wherein said exposure apparatus comprises an optical system including an optical element made of fluoride crystal, said fluoride crystal being manufactured by a method including the steps of adding scavenger and a material to a crucible, melting the scavenger and material at a temperature higher than a melting point so that a ratio of a thickness of the fluoride crystal that has been melted to an inner diameter of the crucible may be 0.2 or higher, and gradually crystallizing and purifying the material.
Dependencies are inferred from the claim text.