Abstract: The present invention provides a method of manufacturing a vitreous silica crucible having a transparent layer by use of waste vitreous silica, and silica powder suitable for the manufacturing. According to the present invention, there is provided a method of manufacturing granulated silica powder comprising a process for pulverizing waste vitreous silica generated in the manufacturing process of a crucible to form silica fine powder having an average particle diameter of 100 ?m or less, and a process for granulating the silica fine powder to obtain granulated silica powder having an average particle diameter of 50 ?m or more under helium atmosphere.

Abstract: The purpose of the present invention is to provide a crucible which has high viscosity at high temperature, can be used for a long time, and can be manufactured at low cost, and a method of manufacturing the crucible. The present invention provides a composite crucible including a vitreous silica crucible body having a sidewall portion and a bottom portion, and a reinforcement layer provided on an outer surface side of an upper end portion of the vitreous silica crucible body, wherein the reinforcement layer is made of mullite material whose main component is alumina and silica.

Abstract: The present invention provides a vitreous silica crucible which can restrain deterioration of crystallinity of a silicon ingot in multi-pulling. Provided is a vitreous silica crucible for pulling a silicon single crystal, the crucible has a wall having, from an inner surface toward an outer surface of the crucible, a synthetic vitreous silica layer, a natural vitreous silica layer, an impurity-containing vitreous silica layer and a natural vitreous silica layer.

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 composite crucible 10 is characterized in the use of mullite (3Al2O3.2SiO2) as the basic material of the crucible. The composite crucible 10 has a crucible body 11 made of mullite material whose main component is alumina and silica, and a transparent vitreous silica layer 12 formed on the inner surface of the crucible body 11. The thickness of the transparent vitreous silica layer 12 is smaller than that of the crucible body 11. The crucible body 11 is formed by the slip casting method, and the transparent vitreous silica layer 12 is formed by the thermal spraying method.

Abstract: The present invention provides a method of evaluating silica powder which, enables precise prediction of easiness of crystallization of a vitreous silica crucible. According to the present invention, provided is a method of evaluating silica powder including a sample preparation process for preparing a vitrified sample by fusing silica powder at a fusing temperature of 1700 to 1900 deg. C., followed by cooling; a sample heat treatment process for retaining the sample for 30 minutes or more at a temperature of 1400 to 1750 deg. C., followed by cooling; and a sample evaluation process for evaluating a state of opacification of the sample after the sample heat treatment process.

Abstract: A vitreous silica crucible has high strength at high temperature, and allows easy taking-out from a susceptor after completion of pulling. The vitreous silica crucible includes a vitreous silica outer layer provided on the outer surface side of the crucible, a vitreous silica inner layer provided on the inner surface side of the crucible, and an vitreous silica intermediate layer provided between the vitreous silica outer layer and the vitreous silica inner layer. The vitreous silica outer layer has a mineralizer concentration of 100 ppm or more, and the vitreous silica intermediate layer and the vitreous silica inner layer has a mineralizer concentration of 50 ppm or less. The thickness of the vitreous silica outer layer is 0.5 mm to 2.0 mm on the bottom portion, and the thickness on the sidewall portion of the vitreous silica outer layer is larger than that on the bottom portion.

Abstract: Accurate temperature measurement during manufacturing a vitreous silica crucible is enabled. The present invention provides an apparatus for manufacturing a vitreous silica crucible including: a mold for forming a silica powder layer by supplying silica powder therein; an are discharge unit having carbon electrodes and a power supply unit and for heating and fusing the silica powder layer by arc discharge; and a temperature measurement unit for measuring temperature of a fused portion in the mold, wherein the temperature measurement unit is an radiation thermometer for measuring temperature by detecting radiation energy of a wavelength of 4.8 to 5.2 ?m.

Abstract: Provided is a vitreous silica crucible which can suppress inward sagging and buckling of the sidewall effectively even when time for pulling silicon ingots is extremely long. According to the present invention, provided is a vitreous silica crucible for pulling a silicon single crystal, wherein the crucible has a wall comprising, from an inner surface toward an outer surface of the crucible, a transparent vitreous silica layer having a bubble content rate of less than 0.5%, a bubble-containing vitreous silica layer having a bubble content rate of 1% or more and less than 50%, a semi-transparent vitreous silica layer having a bubble content rate of 0.5% or more and less than 1.0% and having an OH group concentration of 35 ppm or more and less than 300 ppm.

Abstract: The purpose of the present invention is to provide a crucible which has high viscosity at high temperature, and can be used for a long time, and can be manufactured at low cost, and a method of manufacturing the same. The composite crucible 10 is characterized in the use of mullite (3Al2O3.2SiO2) as the basic material of the crucible. The composite crucible 10 has the crucible body 11 made of mullite material whose main component is alumina and silica, and a transparent vitreous silica layer 12 formed on the inner surface of the crucible body 11. The thickness of the transparent vitreous silica layer 12 is smaller than that of the crucible body 11. The crucible body 11 can be formed by the slip casting method, and the transparent vitreous silica layer 12 can be formed by the thermal spraying method.

Abstract: Provided is a method of manufacturing a vitreous silica crucible for pulling a silicon single crystal which can suppress melt surface vibration of silicon melt filled therein and has a long lifetime. The crucible includes a peripheral wall portion, a curved portion and a bottom portion, and has a plurality of micro recesses on the specific region of the inner surface of the peripheral wall portion.

Abstract: Provided is a vitreous silica crucible which has a special region for suppressing vibration of melt surface during pulling of a silicon single crystal and at the same time, a marking capable of accurately monitoring a changed position of the melt surface when passing through the special region. The special region for preventing sloshing of silicon melt is provided on an inner wall of a straight body portion, and the marking is provided at least at an upper end and a lower end of the special region.

Abstract: The present invention provides a vitreous silica crucible which can suppress buckling and sidewall lowering of the crucible in multi-pulling. According to the present invention, provided is a vitreous silica crucible for pulling a silicon single crystal, comprising a mineralizer on an inner surface of the crucible, wherein the mineralizer contains at least one atoms selected from the group consisting of Ca, Sr, Ba, Ra, Ti, Zr, Cr, Mo, Fe, Co, Ni, Cu, and Ag, and the concentration of the mineralizer on the inner surface is 1.0×105 to 1.0×1017 atoms/cm2.

Abstract: There is provided a method of manufacturing a vitreous silica crucible having a suitably controlled inner surface property. The present invention provides a method of manufacturing a vitreous silica crucible by heating and fusing a silica powder layer in a rotating mold by arc discharge generated by carbon electrodes including: a preparation process for determining optimal fusing temperatures during heating and fusing the silica powder layer at plural points of different heights of the silica powder layer; a temperature measuring process for measuring actual temperatures during heating and fusing the silica powder layer at the plural points; a temperature controlling process for controlling the actual temperatures at the plural points so that the actual temperatures matches the optimal fusing temperatures at the respective points.

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 can suppress buckling and sidewall lowering of the crucible and the generation of cracks. According to the present invention, a vitreous silica crucible is provided for pulling a silicon single crystal having a wall, the wall including a non-doped inner surface layer made of natural vitreous silica or synthetic vitreous silica, a mineralizing element-maldistributed vitreous silica layer containing dispersed island regions each containing a mineralizing element, and wherein the vitreous silica of the island regions and the vitreous silica of a surrounding region of the island regions is a combination of mineralizing element-doped natural vitreous silica and non-doped synthetic vitreous silica, or a combination of mineralizing element-doped synthetic vitreous silica and non-doped natural vitreous silica, and the inner surface layer is made of vitreous silica of a different kind from that of the island region.

Abstract: The present invention provides a vitreous silica crucible which can suppress the sidewall lowering of the crucible under high temperature during pulling a silicon single crystal, and a method of manufacturing such a vitreous silica crucible. The vitreous silica crucible 10 includes an opaque vitreous silica layer 11 provided on the outer surface side of the crucible and containing numerous bubbles, and a transparent vitreous silica layer 12 provided on the inner surface side. The opaque vitreous silica layer 11 includes a first opaque vitreous silica portion 11a provided on the crucible upper portion, and a second opaque vitreous silica portion 11b provided on the crucible lower portion. The specific gravity of the second opaque vitreous silica portion 11b is 1.7 to 2.1, and the specific gravity of the first opaque vitreous silica portion 11a is 1.4 to 1.8, and smaller than that of the second opaque vitreous silica portion.

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: 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 is manufactured by rotational molding in such a manner that the three-dimensional shape thereof matches design data to a high degree. If the degree of matching between three-dimensional shapes of simulation data obtained based on initial property parameters and measurement data falls below a predetermined level, improved property parameters are set such that the degree of matching becomes higher than or equal to the predetermined level. If the degree of matching between three-dimensional shapes of simulation data obtained based on initial manufacturing conditions and the measurement data falls below a predetermined level, improved manufacturing conditions are set such that simulation data matching design data to a degree higher than or equal to the predetermined level is obtained. As a result, the degree of matching between the three-dimensional shapes of the design data and measurement data of the vitreous silica crucible can be enhanced to the predetermined level or higher.