Abstract: A glass plate structure includes: a glass plate having first and second major surfaces; an antireflection film; and a print portion. The first major surface includes: a curved surface region that is a region of an end portion of the glass plate, is curved convexly, and has a radius of curvature r that is 50% or more of a thickness t of the glass plate; and a flat surface region that is connected to the curved surface region. The antireflection film is a laminate in which a high refractive index layer and a low refractive index layer are laminated alternately. The number of layers of the antireflection film is 12 or smaller. A total thickness of the antireflection film in the flat surface region is 400 nm or smaller. A thickness of an outermost layer of the antireflection film in the flat surface region is 90 nm or larger.

Abstract: A machining apparatus for a curved plate includes a holder that holds a main surface of a curved plate having curved surfaces on both main surfaces; a machining device that machines an outer circumference of the curved plate held by the holder; a movable frame that retains the machining device; a driver that moves the movable frame to move a machining point of the curved plate held by the holder; a controller that controls the driver; and a guide that guides the movable frame along the outer circumference of the curved plate held by the holder.

Abstract: A machining apparatus for a curved plate includes a holder that holds a main surface of a curved plate having curved surfaces on both main surfaces; a machining device that machines an outer circumference of the curved plate held by the holder; a movable frame that retains the machining device; a driver that moves the movable frame to move a machining point of the curved plate held by the holder; a controller that controls the driver; and a guide that guides the movable frame along the outer circumference of the curved plate held by the holder.

Abstract: A glass sheet includes a main surface, a first end surface perpendicular to the main surface, and a chamfered surface provided adjacent to the main surface and between the main surface and the first end surface. In a cross section perpendicular to the main surface and the first end surface, a point at which an imaginary line of the first end surface and an imaginary line of the chamfered surface intersect is a first intersection point, and a point at which a straight line that passes through the first intersection point, is perpendicular to the imaginary line of the first end surface and is extended toward the chamfered surface intersects the chamfered surface is a second intersection point. A line segment connecting the first intersection point and the second intersection point has a length of 10 ?m or less.

Abstract: A glass sheet includes a first surface; a second surface facing the first surface; and at least one first edge surface disposed between the first surface and the second surface. A mean height We of a waviness profile element of the first edge surface and a mean length WSm of the waviness profile element satisfy Formula (1) below. W c ? 1 0.6 ? ? 2 ? ( n g - 1 ) · WSm 2 ( 1 ) where ng represents a refractive index of the glass sheet.

Abstract: A method for manufacturing a glass plate including a polishing step of polishing a curved surface of the glass plate using a polisher; wherein the polisher is a rotating brush including a rotating core and brush bristles provided on an external surface of the rotating core, an average diameter of the brush bristle being not more than 300 ?m, and wherein in the polishing step, a position of the rotating brush relative to the glass plate is reciprocated along an axial direction of the rotating brush at a reciprocating speed of not less than 1 mm/sec and a reciprocating amplitude of not less than 0.5 mm.

Abstract: The present invention relates to a glass member including a glass and a reflection sheet, in which the glass includes: a first surface; a second surface opposite to the first surface; at least one first end surface that is provided between the first surface and the second surface; and at least one second end surface that is provided between the first surface and the second surface and is different from the first end surface, the glass has an effective optical path length of 5 cm to 200 cm, the glass has an average internal transmittance of at least 80% in a visible light region over the effective optical path length, the second end surface has a surface roughness Ra of not higher than 0.8 ?m, and the reflection sheet is disposed on the second end surface, and relates to a glass for use in the glass member.

Abstract: A glass includes a first surface; a second surface that faces the first surface; at least one first end surface arranged between the first surface and the second surface; and at least one first chamfering surface connecting the first surface or the second surface with the first end surface. A surface roughness Ra of the first chamfering surface is 0.4 ?m or less.

Abstract: A glass member includes a glass plate, on a first surface of which a functional layer is formed. A Martens hardness measured from a side of the functional layer of the glass member is 1100 N/mm2 or more. The functional layer includes silica. A cut level difference R?c obtained from a roughness curve for a surface of the functional layer is 2% or more. The cut level difference R?c is obtained by subtracting a load length ratio for a cut level of 10%, Rmr(10), from the load length ratio for the cut level of 50%, Rmr(50). The load length ratio for the cut level c is obtained by formula Rmr ? ( c ) = 1 L ? ? i = 1 n ? ? M ? ( c ) i × 100 where M(c)i is a cut length of an i-th cut portion. By cutting the roughness curve at the cut level c within a region having a length L, n cut portions are obtained.

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 ?m or less.

Abstract: The present invention is to provide a method for smoothing the optical surface having a concave defect of an optical component for EUVL. The present invention relates to a method for smoothing the optical surface of an optical component for EUVL, comprising irradiating, with an excimer laser having a wavelength of 250 nm or less with a fluence of 0.5 to 2.0 J/cm2, the optical surface having a concave defect of an optical component for EUV lithography (EUVL), the optical component being made of a TiO2-containing silica glass material comprising SiO2 as a main component.

Abstract: The present invention is to provide a processing method for manufacturing a highly flat and highly smooth glass substrate with good productivity. A highly flat and highly smooth glass substrate is obtained with good productivity by processing of a glass substrate, which comprises a step of measuring the surface shape of the glass substrate prior to processing, a step of processing the surface of the substrate by changing a processing condition for each site (first processing step), and a step of finish-polishing the surface of the glass substrate that has been subjected to the first processing step (second processing step).

Abstract: An object of the present invention is to provide a polishing method for diminishing concave defects of a glass substrate used in a reflective mask for EUVL and the like. The invention relates to a method of polishing a glass substrate which comprises polishing a major surface of the glass substrate while feeding a polishing slurry between the glass substrate and a pad surface of a polishing pad, wherein the polishing load of the polishing pad is from 1 to 60 g/cm2. The pad surface of the polishing pact is preferably dressing-processed.

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 ?m or less.

Abstract: The present invention relates to a glass substrate for a magnetic recording medium, which is a disk-shaped glass substrate for a magnetic recording medium having a circular hole at the center thereof, in which the glass substrate for a magnetic recording medium has an inner peripheral side surface, an outer peripheral side surface and both main surfaces, and the both main surfaces have parallelism of 3.2 ?m or less in at least a recording and reproducing region thereof.

Abstract: The present invention relates to a process for producing a glass substrate, the process including: a lapping step of grinding a main surface of a glass substrate; and a main-surface polishing step of polishing the main surface of the glass substrate after the lapping step, in which the lapping step includes: a primary lapping step of grinding the main surface of the glass substrate with a free abrasive or a fixed abrasive; a secondary lapping step of grinding the main surface of the glass substrate with a fixed abrasive having a smaller particle size than the free abrasive or the fixed abrasive used in the primary lapping step; and a cleaning step of cleaning the main surface of the glass substrate by at least one selected from the group consisting of ultrasonic cleaning, scrub cleaning and acid cleaning, after the primary lapping step but before the secondary lapping step.

Abstract: Spots generated on a glass substrate after a polishing step are reduced. The present invention relates to a method for polishing a glass substrate including injecting a silica abrasive and a high-boiling solvent in a final glass substrate polishing step. The high-boiling solvent is preferably a solvent having a molecular weight of 300 or lower and a boiling point of 150° C. or higher. As Examples of the high-boiling solvent having a molecular weight of 300 or lower and a boiling point of 150° C. or higher includes ethylene glycol, propylene glycol and glycerine.

Abstract: The present invention aims at providing a glass substrate required to have a surface polished with extremely high accuracy as in glass substrates for reflective masks for use in EUVL; and a polishing method for producing the glass substrate. The present invention provides a glass substrate for mask blank, which is a glass substrate comprising SiO2 as a main component and having a polished main surface, wherein concave defects and convex defects on the main surface have a depth of 2 nm or smaller and a height of 2 nm or smaller, respectively, and have a half-value width of 60 nm or smaller, so that the concave defects and/or the convex defects do not cause phase defects when the glass substrate is used to produce a mask for exposure and the mask is used. Also disclosed are a polishing method for producing the glass substrate, and a mask blank and a mask for exposure using the glass substrate.

Abstract: There is provided a process for smoothing a substrate surface having a concave defect, such as a pit or a scratch. A process for smoothing a surface of a glass substrate for a reflective mask blank used in EUV lithography, comprising disposing a thin film on a glass substrate; detecting a concave defect existing on the glass substrate; and locally heating or locally anodizing a portion of the thin film just above the detected concave defect to perform a chemical reaction accompanied by a volume increase in a material forming the thin film.

Abstract: The present invention is to provide a method for smoothing the optical surface having a concave defect of an optical component for EUVL. The present invention relates to a method for smoothing the optical surface of an optical component for EUVL, comprising irradiating, with an excimer laser having a wavelength of 250 nm or less with a fluence of 0.5 to 2.0 J/cm2, the optical surface having a concave defect of an optical component for EUV lithography (EUVL), the optical component being made of a TiO2-containing silica glass material comprising SiO2 as a main component.