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: During fabrication of a vitreous silica crucible, contamination of the vitreous silica crucible due to wear particles and debris of components of an apparatus for manufacturing a vitreous silica crucible is reduced by preventing damage and wear of the components of the apparatus due to silica fume. The apparatus for manufacturing a vitreous silica crucible is divided into a lower section for accommodating a mold and a mold driving system and an upper section for accommodating an arc electrode driving system, wherein a sectioning member including one or more communication paths for allowing penetration of arc electrodes, thereby the air flow is controlled so as to reduce exchange between gas in the upper section and gas in the lower section.

Abstract: Provided is a method of manufacturing a vitreous silica crucible, including: an arc fusing process for fusing the silica powder molded body by using arc flames generated from the plurality of carbon electrodes, wherein the arc fusing process is performed in a state of disposing tips of at least a pair of carbon electrodes of the plurality of carbon electrodes closer to a target surface of the silica powder molded body than other carbon electrode tips, and setting distances from each of the tips of the closer carbon electrodes to the target surface, to be equal, and the arc fusing process is performed by heating and fusing the silica powder molded body while performing fire polishing, which partially removes an inner surface of the silica powder molded body by using arc flames generated by the closer carbon electrodes.

Abstract: A vitreous silica crucible manufacturing apparatus includes a plurality of carbon electrodes configured to heat and melt raw material powder by arc discharge, and a value of a ratio R2/R1 of a diameter R2 of a front end of each of the carbon electrodes to a diameter R1 of a base end is set in a range of 0.6 to 0.8. Each carbon electrode has a diameter reduction portion formed at a front end position and reduced in diameter from a diameter R3 of a base end side to the diameter R2 of the front end. When a length of the diameter reduction portion is L1, the diameter of the front end is R2, the diameter of the base end is R1, an angle between the axis lines of the carbon electrodes is ?1, and X=(R1?R2)/2, a value of L1?(X/tan(?1/2)) is set in a range of 50 to 150 mm.

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 vitreous silica 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 temperatures at measuring points provided on different heights of an inner surface of the silica powder layer while rotating the mold, and controlling the arc discharge to enable detection, at each measuring point, of a local maximum point which appears first in the arc fusing process.

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: 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: 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 arc 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: 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: The present invention provides a method of manufacturing a vitreous silica crucible including: a taking-out process of taking out the vitreous silica crucible from the mold, a honing process of removing the unfused silica powder layer on the outer surface of the vitreous silica crucible, and further comprising, after the taking-out process and before the honing process, a marking process of marking an identifier comprised of one or more groove line on the outer surface of the vitreous silica crucible, wherein the groove line after the honing process has a depth of 0.2 to 0.5 mm, and a width of 0.8 mm or more at the opening of the groove line.

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: 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 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 of manufacturing a vitreous silica crucible by a rotary mold method, which includes performing arc melting in a state in which electrodes are provided so as to be shifted from a mold central line, wherein, by this eccentric arc, the glass temperature difference during melting of a straight body portion, a curved portion and a bottom of the crucible is controlled to 300° C. or below and the thickness of a transparent layer of the straight body portion and the bottom is controlled to 70 to 120% of the thickness of a transparent layer of the curved portion.

Abstract: In order to provide method and apparatus for manufacturing a vitreous silica crucible with little mixing of foreign matter and stable arc during arc melting, the method and apparatus for manufacturing a vitreous silica crucible have a device which blows off air from the side of arc electrodes toward a melting space of a mold, and air discharge ports which discharge the air within the heating furnace, and perform forced supply of air into the melting space during melting to make the atmospheric pressure of the melting space higher than the surroundings, and preferably, form an air pressure difference of 100 Pa or more between the melting space and the surroundings, thereby performing melting.

Abstract: Provided is a vitreous silica crucible, which is resistant to deformation and corrosion even when heated at high temperature for a long time. There is provided a vitreous silica crucible of the present invention including a substantially cylindrical straight body portion, a curved bottom portion, and a corner portion smoothly connecting the straight body portion and the bottom portion, wherein a wall of the vitreous silica crucible includes, from an inner surface side, a transparent layer and a bubble-containing layer, and a ratio of a thickness of the bubble-containing layer with respect to a thickness of the transparent layer at an intermediate position between an upper end and a lower end of the straight body portion is 0.7 to 1.4.

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: 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: 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: Provided is an apparatus for manufacturing a vitreous silica crucible which has a structure which can reduce gaps between a partition wall and electrodes inserted into through-holes formed in the partition wall while enabling electrodes to move to adjust a heating temperature of arc discharge. A plate-shaped partition wall 15 is placed above the rotating mold 10. Electrodes 13 for heating and fusing are inserted into through-holes 16 penetrating in a thickness direction, and are directed toward the rotating mold 10. A rocking unit 40 is provided on an upper side of the partition wall 15 and rocks the electrodes 13 around virtual rocking axes P, and the virtual rocking axes P pass through the through-holes 16.