Low expansion glass substrate for reflection type mask and method for processing same
AssigneeAsahi Glass Company, Limited
InventorsKenji Okamura, Masabumi Ito, Hiroshi Kojima
Life of this patent
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Abstract
The present invention relates to a low expansion glass substrate which serves as a substrate of a reflective mask used in a lithography step of semiconductor production steps, wherein two side surfaces positioned to face each other among side surfaces formed along a periphery of the low expansion glass substrate, each have a flatness of 25 μm or less.
Claims20
A substrate for a reflective mask in a semiconductor production lithography, comprising:
- a low expansion glass substrate having a plurality of main surfaces and a plurality of side surfaces formed along a periphery of the main surfaces of the low expansion glass substrate, the plurality of side surfaces including two side surfaces positioned to face each other,
- wherein each of the two side surfaces has a flatness which is a difference in height of 25 μm or less.
A substrate for a reflective mask in a semiconductor production lithography, comprising:
- a low expansion glass substrate having a plurality of main surfaces and a plurality of side surfaces formed along a periphery of the main surfaces of the low expansion glass substrate, the plurality of side surfaces including two side surfaces positioned to face each other,
- wherein the low expansion glass substrate has a plurality of chamfered portions formed at corners between the two side surfaces and main surfaces of the low expansion glass substrate, and each of the chamfered portions has a flatness which is a difference in height of 25 μm or less.
A substrate for a reflective mask in a semiconductor production lithography, comprising:
- a low expansion glass substrate having a plurality of main surfaces and a plurality of side surfaces formed along a periphery of the main surfaces of the low expansion glass substrate, the plurality of side surfaces including two side surfaces positioned to face each other,
- wherein the low expansion glass substrate has a plurality of chamfered portions formed at corners between the two side surfaces and main surfaces of the low expansion glass substrate, and each of the two side surfaces and chamfered portions has a flatness which is a difference in height of 25 μm or less.
A method for processing a low expansion glass substrate for a reflective mask in a semiconductor production lithography, the method comprising:
- providing a low expansion glass substrate having a plurality of main surfaces and a plurality of side surfaces formed along a periphery of the main surfaces of the low expansion glass substrate, the plurality of side surfaces including two side surfaces positioned to face each other;
- measuring after pre-polishing a difference in height as a flatness of each of the two side surfaces;
- and
- setting processing conditions of the two side surfaces in site by site based on the flatness of each of the two side surfaces.
Dependencies are inferred from the claim text.