Substrate for reticle and method of manufacturing the substrate, and mask blank and method of manufacturing the mask blank
AssigneeHoya Corporation
InventorHiroyuki Akagawa
Life of this patent
Estimating the term…
Abstract
In a reticle substrate is used for forming a reticle held on a stepper and has main surfaces opposing each other, side faces, and chamfered surfaces formed between main surfaces and side faces, a flatness-measuring area is defined as an area excluding a peripheral area of a width of 3 mm inwardly laid from a boundary between the main surface and the chamfered surfaces and has a flatness of 0.5 μm or less, and a maximum height from a reference plane falls between −1 and 0 μm at the boundary between the main surface and the chamfered surface
Claims16
A reticle substrate comprising a pair of main surfaces opposing each other, two pairs of side faces that are right to the main surfaces and that are opposed in pair to each other, and chamfered surfaces between the main surfaces and the side faces, wherein:
- a flatness is not greater than 0.5 μm on a flatness measurement area of each main surface, from which an area of 3 mm laid inwardly from a boundary between the main surface and the chamfered surface is excluded, while the boundary between the main surface and the chamfered surface has a maximum height between −1 and 0 μm from a reference surface.
A reticle substrate comprising a pair of main surfaces opposing each other, two pairs of side faces right to the main surfaces wherein the two side faces of each pair opposing each other, and chamfered surfaces between the main surfaces and the side faces, wherein:
- a flatness is not greater than 0.5 μm on a flatness measurement area of each main surface, from which an area of 3 mm laid inwardly from a boundary between the main surface and the chamfered surface is excluded, while the boundary between the flatness-measuring area and a flatness non-measuring area has a maximum height between −1 and 0 μm from a reference surface.
Dependencies are inferred from the claim text.