Glass substrate for an electron device, photomask blank and photomask using the same
AssigneeHoya Corporation
InventorMASARU TANABE
Life of this patent
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Abstract
In a glass substrate for an electron device which is selected based upon a predetermined reference set value using a method for detecting a defect for the glass substrate in accordance with optical change of an inspecting light beam, the defect for the glass substrate has no dependency for a moving direction of the inspecting light beam.
Claims23
A glass substrate for an electron device which is selected based upon a predetermined reference set value using a method for detecting a defect for said glass substrate in accordance with optical change of an inspecting light beam, wherein:
- the defect for said glass substrate has no dependency for a moving direction of the inspecting light beam.
A glass substrate for an electron device which has a concave portion on a principal surface of said glass substrate, wherein:
- said concave portion is represent by a first length of a major axis direction and a second length of a minor axis direction perpendicular to the major axis direction in size,
- the second length on the principal surface specified when the concave portion is cut by a cross sectional plane perpendicular to the principal surface being 1 μm or less, and
- the principal surface being positioned at a side in which a pattern is formed.
A glass substrate for an electron device, wherein:
- a non-uniform portion, in which optical characteristic for a transmitted light beam is non-uniform, does not substantially exists inside said glass substrate.
Dependencies are inferred from the claim text.