Abstract: Buckling of a vitreous silica crucible or fall of a sidewall into the crucible is effectively suppressed. Furthermore, dislocations in a silicon single crystal are suppressed to enhance the yield of the single crystal. The vitreous silica crucible is used to pull single-crystal silicon and includes the cylindrical sidewall having an upward-opening rim, a mortar-shaped bottom including a curve, and a round portion connecting the sidewall and the bottom. The round portion is provided in such a manner that the curvature of the inner surface thereof is gradually increased from the sidewall toward the bottom in a section passing through the rotation axis of the vitreous silica crucible.

Abstract: A vitreous silica crucible used to pull up silicon single crystal includes: a cylindrical straight body portion, a corner portion formed at a lower end of the straight body portion, and a bottom portion connected with the straight body portion via the corner portion, wherein the vitreous silica crucible further comprises: an opaque outer layer enclosing bubbles therein; and a transparent inner layer from which bubbles are removed, wherein the residual distortion's distribution obtained by measuring the silica glass's inner surface in a non-destructed state has an optical path difference which is 130 nm or less, which residual distortion's distribution is measured using a distortion-measuring apparatus which converts a linearly polarized light into circularly polarized light and then irradiates the crucible's wall.

Abstract: A destructive inspection method of a vitreous silica crucible for pulling a silicon single crystal evaluates a crack state of an inner surface of the vitreous silica crucible supported by a graphite susceptor when a load is instantaneously applied to at least one point on the inner surface via an automatic center punch while pushing the tip portion of the automatic center punch against the inner surface. The destructive inspection method can inspect the vitreous silica crucible under conditions as close to the actual conditions of use as possible.

Abstract: A vitreous silica crucible includes: a substantially cylindrical straight body portion having an opening on a top end and extending in a vertical direction; a curved bottom portion; and a corner portion connecting the straight body portion with the bottom portion and a curvature of which is greater than that of the bottom portion, wherein an inner surface of the crucible has a concavo-convex structure in which groove-shaped valleys are interposed between ridges, and an average interval of the ridges is 5-100 ?m.

Abstract: A vitreous silica crucible used to pull up silicon single crystal includes: a cylindrical straight body portion, a corner portion formed at a lower end of the straight body portion, and a bottom portion connected with the straight body portion via the corner portion, wherein the vitreous silica crucible further comprises: an opaque outer layer enclosing bubbles therein; and a transparent inner layer from which bubbles are removed, wherein the residual distortion's distribution obtained by measuring the silica glass's inner surface in a non-destructed state has an optical path difference which is 130 nm or less, which residual distortion's distribution is measured using a distortion-measuring apparatus which converts a linearly polarized light into circularly polarized light and then irradiates the crucible's wall.

Abstract: In an embodiment, a vitreous silica crucible 1 includes a cylindrical straight body portion 10a, a corner portion 10c formed at lower end of the straight body portion 10a, and a bottom portion 10b connected with the straight body portion 10a via the corner portion 10c. Moreover, the vitreous silica crucible 1 includes a bubble-containing opaque layer 11 constituting an outer layer, and a bubble-free transparent layer 12 constituting an inner layer. A boundary surface, between the opaque layer 11 and the transparent layer 12 in at least the straight body portion 10a, forms a periodic wave surface in a vertical direction. The vitreous silica crucible can suppress deformation under high temperature.

Abstract: A method for pulling silicon single crystal includes a process of placing a molded body between a susceptor's inner surface and a crucible's outer surface. The molded body is formed based on three-dimensional data of the inner surface shape of the susceptor which can hold the vitreous silica crucible and three-dimensional data of the crucible so as to make the susceptor's central axis and the crucible's central axis substantially aligned when it is placed between the susceptor's inner surface and the crucible's outer surface.

Abstract: In an embodiment, a distortion-measuring apparatus for measuring a distortion distribution of an entire vitreous silica crucible in a non-destructive way includes: a light source 11; a first polarizer 12 and a first quarter-wave plate 13 disposed between the light source 11 and an outer surface of a vitreous silica crucible wall; a camera 14 disposed inside of a vitreous silica crucible 1; a camera control mechanism 15 configured to control a photographing direction of the camera 14; a second polarizer 16 and a second quarter-wave plate 17 disposed between the camera 14 and an inner surface of the vitreous silica crucible wall. An optical axis of the second quarter-wave plate 17 inclines 90 degrees with respect to the first quarter-wave plate 13.

Abstract: The present invention provides a method for evaluating a vitreous silica crucible which can measure a three-dimensional shape of the inner surface of the crucible in a non-destructive manner.

Abstract: A method for measuring a three-dimensional shape of an inner surface of a vitreous silica crucible which enables the measurement of the three-dimensional shape of the inner surface of the crucible without contaminating the inner surface of the crucible, is provided. According to the present invention, a method for measuring a three-dimensional shape of a vitreous silica crucible, including a fogging step to form a fog onto an inner surface of the vitreous silica crucible, a three-dimensional shape measuring step to measure a three-dimensional shape of the inner surface, by measuring a reflected light from the inner surface irradiated with light, is provided.

Abstract: The present invention provides a vitreous silica crucible which can suppress buckling and sidewall lowering of the crucible without fear of mixing of impurities into silicon melt. According to the present invention, provided is a vitreous silica crucible for pulling a silicon single crystal, wherein a ratio I2/I1 is 0.67 to 1.17, where I1 and I2 are area intensities of the peaks at 492 cm?1 and 606 cm?1, respectively, in Raman spectrum of vitreous silica of the region having a thickness of 2 mm from an outer surface to an inner surface of a wall of the crucible.

Abstract: Spatial coordinates of multiple points on an inner surface of a vitreous silica crucible are measured prior to filling raw material in the vitreous silica crucible, and a three-dimensional shape of the inner surface of the vitreous silica crucible using a combination of polygons having vertex coordinates constituted by the respective measured points is specified (S11); a predictive value of an initial liquid surface level of the silicon melt in the vitreous silica crucible is preset (S12); a volume of the silicon melt satisfying the predictive value of the initial liquid surface level is obtained based on the three-dimensional shape of the inner surface of the vitreous silica crucible (S13); a weight of the silicon melt having the volume is obtained (S14); raw material having the weight is filled in the vitreous silica crucible (S15); a dipping control of the seed crystal is performed based on the predictive value of the initial liquid surface level (S17).

Abstract: A destructive inspection method of a vitreous silica crucible for pulling a silicon single crystal evaluates a crack state of an inner surface of the vitreous silica crucible supported by a graphite susceptor when a load is instantaneously applied to at least one point on the inner surface via an automatic center punch while pushing the tip portion of the automatic center punch against the inner surface. The destructive inspection method can inspect the vitreous silica crucible under conditions as close to the actual conditions of use as possible.

Abstract: Buckling of a vitreous silica crucible 12 or inward fall of a sidewall 15 is effectively suppressed. The vitreous silica crucible 12 includes the cylindrical sidewall 15 having an upward-opening rim, a mortar-shaped bottom 16 including a curve, and a round portion 17 connecting the sidewall 15 and the bottom 16. In the vitreous silica crucible 12 the per-unit area thermal resistance in the thickness direction of the sidewall 15 is higher than that of the round portion 17.

Abstract: The present invention provides a vitreous silica crucible which inhibits a deformation even when used under a high temperature condition for a long time, and a method for manufacturing the same. The vitreous silica crucible comprises: a substantially cylindrical straight body portion having an opening on the top end and extending in a vertical direction, a curved bottom portion, and a corner portion connecting the straight body portion with the bottom portion and a curvature of which is greater than that of the bottom portion, wherein, the vitreous silica crucible comprises a transparent layer on the inside and a bubble layer on the outside thereof, a compressive stress layer in which compressive stress remains in the inner surface side of the transparent layer, and a tensile stress layer in which tensile stress remains and is adjacent to the compressive stress layer at a gradual rate of change of stress.

Abstract: An apparatus for supporting setting of a manufacturing condition of a vitreous silica crucible includes: an improved property parameter setting unit configured to, if the degree of matching between three-dimensional shapes of simulation data obtained based on an initial property parameter and measurement data falls below a predetermined level, set an improved property parameter such that the degree of matching becomes higher than or equal to the predetermined level, and an improved manufacturing condition data setting unit configured to set a manufacturing condition such that simulation data matching the design data to a degree higher than or equal to a predetermined level is obtained. By using the apparatus, it is possible to manufacture a vitreous silica crucible by rotational molding in such a manner that the three-dimensional shape thereof matches the design data to a high degree.

Abstract: A stainless steel spring with excellent corrosion resistance and fatigue strength is provided by performing: a process of drawing a steel wire at a specific degree of drawing ?, the steel wire containing, in percentage by mass, C in an amount of 0.08% or lower, Si in an amount of 0.3% to 2.0%, Mn in an amount of 3.0% or lower, Ni in an amount of 8.0% to 10.5%, Cr in an amount of 16.0% to 22.0%, Mo in an amount of 0.5% to 3.0%, and N in an amount of 0.15% to 0.23%, with a remainder being made up of Fe and impurities; a process of obtaining a coiled steel wire; a process of heat treatment at from 500° C. to 600° C., and from 20 minutes to 40 minutes; a process of nitriding to form a nitride layer having a thickness of from 40 ?m to 60 ?m on a surface of the steel wire; a process of shot peening; and a process of heat treatment.

Abstract: A quality-evaluated vitreous silica crucible for pulling silicon single crystal is provided, wherein an inner surface of the vitreous silica crucible has regions where surface defects including brown rings are to be generated when pulling silicon single crystal. The regions are distinguished using an infrared absorption spectrum or a Raman shift of the regions, wherein a position of each region and/or a density of the regions are/is specified.

Abstract: A method of manufacturing of a vitreous silica crucible includes: fusing silica powder under a reduced pressure of ?50 kPa or more and less than ?95 kPa to form a transparent vitreous silica layer as an inner layer; fusing silica powder under a reduced pressure of 0 kPa or more and less than ?10 kPa to form a bubble-containing vitreous silica layer as an intermediate layer; and fusing silica powder under a reduced pressure of ?10 kPa or more and less than ?50 kPa to form a semi-transparent vitreous silica layer as an outer layer.

Abstract: A quality-evaluated vitreous silica crucible for pulling silicon single crystal is provided, wherein an inner surface of the vitreous silica crucible has regions where surface defects including brown rings are to be generated when pulling silicon single crystal. The regions are distinguished using an infrared absorption spectrum or a Raman shift of the regions, wherein a position of each region and/or a density of the regions are/is specified.