Abstract: A mask blank glass substrate having a maximum value of a circularly averaged power spectral density of 1,000 nm4 or less at a spatial frequency of 0.1 ?m?1 or more and 20 ?m?1 or less, the maximum value being obtained by measuring a surface morphology of a region of 10 ?m×10 ?m with an atomic force microscope.

Abstract: A substrate for mask blanks having first and second main surfaces of 152 mm×152 mm square and a thickness of 6.35 mm, wherein: when a range of 132 mm×132 mm square centered on an intersection of diagonal lines is defined as a calculation region in each of the first and second main surfaces, on a substrate surface of the calculation region of at least one of the first and second main surfaces, flatness of the substrate surface of the calculation region based on a least square plane is 100 nm or less, and a difference (PV) between a highest value and a lowest value of a height of a calculation surface represented by a difference between shapes of the substrate surfaces before and after smoothing processing with a Gaussian filter (10 mm×10 mm) based on the least square plane is 20 nm or less.

Abstract: Proposed herein is a method for producing a substrate suitable for mask blanks for EUVL and the method being capable of suppressing a concave defect having a depth of less than 5 nm. The present invention provides a method for producing a substrate in which final polishing is performed by a polishing apparatus having an upper polishing plate equipped with a polishing pad, the method comprising the steps of placing a substrate stock in the polishing apparatus so that the main surface of the substrate stock face toward the upper polishing plate; rotating the upper polishing plate and polishing the substrate stock concomitantly with a polishing slurry on the main surface of the substrate stock; and raising the upper polishing plate which is kept being rotated to separate it from the main surface of the polished substrate stock.

Abstract: A mask blank glass substrate having a maximum value of a circularly averaged power spectral density of 1,000 nm4 or less at a spatial frequency of 0.1 ?m?1 or more and 20 ?m?1 or less, the maximum value being obtained by measuring a surface morphology of a region of 10 ?m×10 ?m with an atomic force microscope.

Abstract: A synthetic quartz glass cavity member (1) is bonded to a substrate (6) having an optical device (7) mounted thereon such that the device may be accommodated in the cavity member. The cavity member (1) has an inside surface consisting of a top surface (2a) opposed to the device (7) and a side surface (3a). The top surface (2a) is a mirror surface and the side surface (3a) is a rough surface.

Abstract: The window material for an optical element of the present invention is formed of synthetic quartz glass that is likely to be subjected to shape processing, can be manufactured at low cost, and has a flat plate shape. Even if the window material for an optical element has a flat plate shape, for example, in a window material of a UV-LED such as a UVC-LED sealed with a surface mount package (SMD PKG), light emitted from the optical element, in particular, light having a light distribution angle can be efficiently collected when passing through the window material, and light collection equal to that of a window material having a lens shape such as a conventional convex shape can be achieved. Furthermore, light distribution without irradiation unevenness such as Lambertian reflection can also be achieved.

Abstract: A large-size synthetic quartz glass substrate has a diagonal length of at least 1,000 mm. Provided that an effective range is defined on the substrate surface, and the effective range is partitioned into a plurality of evaluation regions such that the evaluation regions partly overlap each other, a flatness in each evaluation region is up to 3 ?m. From the quartz glass substrate having a high flatness and a minimal local gradient within the substrate surface, a large-size photomask is prepared.

Abstract: A mask blanks substrate having a flatness of a calculation surface of 100 nm or less when a calculation region passing through central portions of first and second main surfaces and extending in a horizontal direction is set, a first region surface is cut out, a second region surface is cut out by setting a reference plane and a rotation axis and rotating the substrate by 180°, least square planes are calculated, the first and second region surfaces are converted into height maps to positions on the least square planes, the height map of the to second region surface is set as a reverse height map by symmetrically moving the height map, and a map of a calculated height obtained by adding heights of the height map of the first region surface and the reverse height map of the second region surface is set as the calculation surface.

Abstract: A polishing composition including a colloidal silica containing colloidal silica particles, a pH adjusting agent, and a chelating agent provides a substrate that has a surface having a high flatness, low defects and a low surface roughness with low cost and high productivity, and a substrate having high surface quality suitable as a substrate for mask blanks such as a glass substrate containing SiO2 as a main component, particularly, as a substrate for mask blanks used in EUVL.

Abstract: A synthetic quartz glass cavity member (1) is bonded to a substrate (6) having an optical device (7) mounted thereon such that the device may be accommodated in the cavity member. The cavity member (1) has an inside surface consisting of a top surface (2a) opposed to the device (7) and a side surface (3a). The top surface (2a) is a mirror surface and the side surface (3a) is a rough surface.

Abstract: A synthetic quartz glass cavity member (1) is bonded to a substrate (6) having an optical device (7) mounted thereon such that the device may be accommodated in the cavity member. The cavity member (1) has an inside surface consisting of a top surface (2a) opposed to the device (7) and a side surface (3a). The top surface (2a) is a mirror surface and the side surface (3a) is a rough surface.

Abstract: A bonding and sealing material includes, as the essential ingredients, a solder powder, silver nanoparticles coated with a coating material and a solvent, and additionally includes at least one ingredient selected from the group consisting of selenium metal, oxide film inhibitors and oxide film removers. This bonding and sealing material can easily form under mild conditions a metallic adhesive layer having good hermetic sealability and UV resistance of the sort desired when sealing a short-wavelength light-emitting device such as a UV-LED, and can be stably used over a long period of time.

Abstract: A mask blank glass substrate having a maximum value of a circularly averaged power spectral density of 1,000 nm4 or less at a spatial frequency of 0.1 ?m?1 or more and 20 ?m?1 or less, the maximum value being obtained by measuring a surface morphology of a region of 10 ?m×10 ?m with an atomic force microscope.

Abstract: A lid for an optical element package, comprising: a window material provided in front of the light emitting direction of an optical element of a housing member, inside of which the optical element is housed; and a metal-based adhesive layer formed on a part at which the window material contacts the housing member, wherein with the lid for an optical element package, the metal-based adhesive layer is formed by an adhesive composition including metal nanoparticles, a solder powder, and a dispersion medium coated by a coating agent. It is possible to address deterioration and cracking due to light of short wavelengths, distortion or decay of the adhesive agent due to heat generation of the light emitting element, and the problem of long-term reliability accompanying these. Specifically, it is possible to provide the lid for an optical element package and the optical element package with excellent heat resistance, ultraviolet resistance, etc.

Abstract: A sealing composition which can be handled in a semi-cured state and can obtain a sintered body having excellent joining strength and sealing performance is provided. A sealing composition including a solder powder, coated silver particles including silver core particles and a coating agent arranged on a surface of the silver core particles, and a solvent is provided. Further, a sintering temperature (T2) of the coated silver particles and a boiling point (T3) of the solvent satisfy T2?T3.

Abstract: A synthetic quartz glass substrate with an antireflection film, including: a synthetic quartz glass substrate; and an antireflection film formed on a main surface of the synthetic quartz glass substrate, wherein a contact angle measured by a sessile drop method of JIS R 3257:1999 of the main surface of the synthetic quartz glass substrate is within 5 degrees, and the antireflection film includes a first layer containing Al2O3, a second layer containing HfO2, and a third layer containing MgF2 or SiO2 sequentially laminated on the main surface of the synthetic quartz glass substrate.

Abstract: A circular mold-forming substrate of 125-300 mm diameter having a surface on which a topological pattern is to be formed is provided wherein the thickness of the substrate has a variation of up to 2 ?m within a circle having a diameter of 125 mm.

Abstract: A large-size synthetic quartz glass substrate has a diagonal length of at least 1,000 mm. Provided that an effective range is defined on the substrate surface, and the effective range is partitioned into a plurality of evaluation regions such that the evaluation regions partly overlap each other, a flatness in each evaluation region is up to 3 ?m. From the quartz glass substrate having a high flatness and a minimal local gradient within the substrate surface, a large-size photomask is prepared.

Abstract: A synthetic quartz glass lid for use in optical device packages is prepared by furnishing a synthetic quartz glass lid precursor comprising a synthetic quartz glass substrate (1) and a metal or metal compound film (2), and forming a metal base adhesive layer (3) on the metal or metal compound film (2). The metal or metal compound film contains Ag, Bi, and at least one element selected from P, Sb, Sn and In.

Abstract: A rectangular glass substrate has a front surface, a back surface, four side surfaces, and eight chamfered surfaces, and a thickness of at least 6 mm. A first curved surface along the edge line between the front surface and the chamfered surface disposed adjacent thereto has an average gradient of up to 25% in a range from the front surface to a position of 50 ?m below the front surface when the substrate is rested horizontal with the front surface facing upward. A second curved surface along the edge line between at least one of four side surfaces and the chamfered surface disposed adjacent to the front surface has an average gradient of at least 30% in a range from the at least one side surface to a position of 50 ?m below the at least one side surface when the substrate is rested horizontal with the at least one side surface facing upward.