Abstract: The present invention provides a method of manufacturing a vitreous silica crucible having a transparent layer by use of waste vitreous silica. According to the present invention, there is provided a method of manufacturing a vitreous silica crucible for manufacturing a monocrystalline or polycrystalline silicon ingot, including a process of vitrifying a silica powder sintered body having a crucible shape in the whole or part of the thickness direction by arc fusing the silica powder sintered body from the inner surface side, wherein the method further includes at least one means of (1) depressurizing the silica powder sintered body from the outer surface side during the arc fusing, and (2) forming a synthetic vitreous silica layer on the inner surface by spraying synthetic silica powder onto the inner surface of the silica powder sintered body during the arc fusing.

Abstract: A closure for silica glass crucible to be mounted on an opening portion of a silica glass crucible is provided with a peripheral edge mounting portion closely adhered to an inner peripheral end of the opening portion.

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: There is provided a silica crucible for pulling a silicon single crystal, comprising silica glass and having a two-layer structure of an outer layer and an inner layer, wherein the inner layer, in a sectional side view of the crucible, has a wavy inner surface shape having mountain parts and valley parts at least between a start position and an end position for the pulling of a silicon single crystal in a silicon melt surface, and when a distance from an upper opening end of the crucible to the start position for the pulling of the silicon single crystal is 100, only a crucible portion from the upper opening end to a position within a range of 40 to 100 is crystalline.

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: A crucible for pulling a silicon single crystal has a double structure comprising a silica crucible and a graphite crucible covering an outside of the silica crucible, wherein the silica crucible is provided at its opening end portion with an inward falling prevention means for imparting a radially outward force to a body portion of the silica crucible.

Abstract: A silica glass crucible for pulling up a silicon single crystal including an outer layer formed from a natural silica glass layer, and an inner layer formed from a synthetic silica glass layer, wherein the synthetic silica glass layer includes a first synthetic silica glass layer formed in a region within a certain range from the center of a crucible bottom section, and a second synthetic silica glass layer formed in a region which excludes the formation region of the first synthetic silica glass layer, and wherein the first synthetic silica glass layer has a thickness of 0.5 mm or more and 1.5 mm or less and a concentration of an OH group included in the first synthetic silica glass layer being 100 ppm or less.

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: 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: A high-purity vitreous silica crucible which has high strength and is used for pulling a large-diameter single-crystal silicon ingot, includes a double laminated structure constituted by an outer layer composed of amorphous silica glass with a bubble content of 1 to 10% and a purity of 99.99% or higher and an inner layer composed of amorphous silica glass with a bubble content of 0.6% or less and a purity of 99.99% or higher, and in the portion between the upper opening end of the high-purity vitreous silica crucible and the ingot-pulling start line of a silicon melt surface in the step of pulling a single-crystal silicon ingot, a portion corresponding to 40 to 100 volume % from the upper opening end of the crucible is in a crystalline structure free from the crystallization promoter.

Abstract: Method of manufacturing a fused silica crucible, including manufacturing a plurality of carbon electrodes for melting a vitreous silica object to be melted by arc discharge by rubbing the surface of a carbon electrode of the electrodes with a vitreous silica of the same type as the vitreous silica object to be melted, by at least one of: inserting a front end of the carbon electrode into a storage tank storing powdered vitreous silica, by at least one of rotating and reciprocating in an axial direction the storage tank and the carbon electrode relative to each other; rubbing the surface of the carbon electrode by ejecting powdered vitreous silica from a nozzle onto the surface of the electrode; rubbing the surface of the electrode with a vitreous silica grinder; and rubbing the surface of the electrode against a rotating surface of a portion of a fused vitreous silica crucible.

Abstract: In order to provide a vitreous silica crucible which does not employ a crystallization accelerator but is difficult to deform during its use even under high temperature, and is easily manufactured, there is provided a vitreous silica crucible for pulling single-crystal silicon wherein the outer surface layer is formed of a bubble-containing vitreous silica layer, the inner surface layer is formed of a vitreous silica layer whose bubbles are invisible to the naked eye, a surface of the outer surface layer includes an unmelted or half-melted silica layer (abbreviated as a half-melted silica layer), and the center line average roughness (Ra) of the half-melted silica layer is 50 to 200 ?m, also preferably, and the thickness of the half-melted silica layer is 0.5 to 2.0 mm.

Abstract: Provided are an apparatus and a method for manufacturing a vitreous silica crucible, which enable accurate measurement of a fume generation amount, prevention of deterioration of an inner surface property, and real-time control of a raw material melting state. Provided is an apparatus for manufacturing a vitreous silica crucible 50 by supplying silica powder into a mold 10 to form a silica powder layer 11, and heating and melting the silica powder layer 11 by arc discharge. The apparatus includes the mold 10 for defining an outer shape of a vitreous silica crucible, an arc discharge unit having a plurality of carbon electrodes 13 and a power-supply unit 40, and a fume-amount measurement unit 30 for detecting an amount of fumes 80 generated in the mold 10.

Abstract: The present invention provides a method of manufacturing a vitreous silica crucible including: a silica powder supplying process of supplying a material silica powder into a mold for molding a crucible, to form a silica powder layer, and an arc fusing process of arc fusing the silica powder layer by arc discharge generated by carbon electrodes, wherein the arc fusing process includes processes of measuring a temperature of the silica powder layer, and controlling a vitreous silica fused state based on a reference temperature which is a temperature at a local maximum point which appears first in the arc fusing process.

Abstract: Provided is a method for manufacturing a vitreous silica crucible and a manufacturing apparatus for the same, which can reduce the amount of bubbles and impurities of a crucible inner surface and enhance a crystallization yield of silicon single crystal. A method for manufacturing a vitreous silica crucible of the invention includes a silica powder supplying process of supplying silica powder in a rotating mold to form a silica powder layer; an arc fusing process of fusing the silica powder layer by arc discharge generated by carbon electrodes; and a fire polishing process of throwing an arc flame toward a target surface of the silica powder layer for surface removal, wherein, in the fire polishing process, the distances from the tips of the carbon electrodes to the target surface is set to be equal.

Abstract: Provided is a method of calculating a temperature distribution with higher accuracy than a conventional method, which calculates a temperature distribution of an inner surface of a silica powder molded body during manufacturing based on boundary conditions corrected in accordance with the actually measured temperature in consideration of plasma radiation by arc discharge and heat radiation of arc discharge.

Abstract: There are provided an apparatus and a method for manufacturing a vitreous silica crucible which can prevent the deterioration of the inner surface property in the manufacturing process of a vitreous silica crucible. The apparatus includes a mold defining an outer shape of a vitreous silica crucible, and an arc discharge unit having electrodes and a power-supply unit, wherein each of the electrodes includes a tip end directed to the mold, the other end opposite to the tip end, and a bent portion provided between the tip end and the other end.

Abstract: 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 comprising: a preparation process for determining optimal temperatures during heating and fusing the silica powder layer for one or more selected from the group consisting of the silica powder layer, fume generated during arc fusing, and arc flame generated in the arc discharge; a temperature measuring process for measuring actual temperatures during heating and fusing for one or more selected from the group where the optimal temperatures are determined; and a temperature controlling process for controlling the actual temperatures for one or more selected from the group where the actual temperatures are measured so that the actual temperatures match the optimal temperatures.

Abstract: A method for manufacturing a silicon single crystal is provided including producing a silicon melt in a chamber by melting a silicon raw material loaded into a silica glass crucible under a reduced pressure and high temperature, removing gas bubbles from within the silicon melt by rapidly changing at least the pressure or temperature within the chamber, and pulling up the silicon single crystal from the silicon melt after the gas bubbles are removed. When the pressure is rapidly changed, the pressure within the chamber is rapidly changed at a predetermined change ratio. In addition, when the temperature is rapidly changed, the temperature within the chamber is rapidly changed at a predetermined change ratio. In this way, Ar gas attached to an inner surface of the crucible and h is the cause of the generation of SiO gas is removed.

Abstract: Provided is a vitreous silica crucible for pulling silicon single crystals, which can melt a silicon raw material in a short time and improve production yield of silicon single crystals by temporal change of an opaque vitreous silica layer. The vitreous silica crucible includes an opaque vitreous silica layer(11) provided on an outer surface thereof and containing plural bubbles, and a transparent vitreous silica layer(12) provided on an inner surface and not containing bubbles substantially. The opaque vitreous silica layer(11) has a bubble diameter distribution in which the content of bubbles having a diameter of less than 40 ?m is 10% or more and less than 30%, the content of bubbles having a diameter of 40 ?m or more and less than 90 ?m is 40% or more and less than 80%, and the content of bubbles having a diameter equal to or more than 90 ?m is 10% or more and less than 30%.