Japan Super Quartz Corporation

Sumco Corporation

Minoru Kanda

Hiroshi Kishi

Takeshi Fujita

Toshiaki Sudo

Yoshiyuki Tsuji

Makiko Kodama

Masanori Fukui

Ken Kitahara

Masaki Morikawa

Takuma Yoshioka

Koichi Suzuki

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 crucibleis characterized in the use of mullite (3AlO.2SiO) as the basic material of the crucible. The composite cruciblehas the crucible bodymade of mullite material whose main component is alumina and silica, and a transparent vitreous silica layerformed on the inner surface of the crucible body. The thickness of the transparent vitreous silica layeris smaller than that of the crucible body. The crucible bodycan be formed by the slip casting method, and the transparent vitreous silica layercan be formed by the thermal spraying method.

Composite crucible, method of manufacturing the same, and method of manufacturing silicon crystal

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 crucibleincludes an opaque vitreous silica layerprovided on the outer surface side of the crucible and containing numerous bubbles, and a transparent vitreous silica layerprovided on the inner surface side. The opaque vitreous silica layerincludes a first opaque vitreous silica portionprovided on the crucible upper portion, and a second opaque vitreous silica portionprovided on the crucible lower portion. The specific gravity of the second opaque vitreous silica portionis 1.7 to 2.1, and the specific gravity of the first opaque vitreous silica portionis 1.4 to 1.8, and smaller than that of the second opaque vitreous silica portion. The particle size distribution of the material silica powder for the first opaque vitreous silica portionis wider than that of the second opaque vitreous silica portionand the material silica powder for the first opaque vitreous silica portionincludes more fine powder than that for the second opaque vitreous silica portion

Vitreous silica crucible for pulling silicon single crystal and method of manufacturing the same

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() provided on an outer surface thereof and containing plural bubbles, and a transparent vitreous silica layer() provided on an inner surface and not containing bubbles substantially. The opaque vitreous silica layer() has a bubble diameter distribution in which the content of bubbles having a diameter of less than 40 &#x3bc;m is 10% or more and less than 30%, the content of bubbles having a diameter of 40 &#x3bc;m or more and less than 90 &#x3bc;m is 40% or more and less than 80%, and the content of bubbles having a diameter equal to or more than 90 &#x3bc;m is 10% or more and less than 30%. Relatively small bubbles contained in the opaque vitreous silica layer() contribute to the thermal conductivity of a crucible at an initial pulling stage, and relatively large bubbles contained in the opaque vitreous silica layer are expanded through a long-term pulling process to thereby largely contribute to the warmth retaining property of the crucible at a later pulling stage.

Vitreous silica crucible for pulling silicon single crystal

To provide a treatment method having excellent purification effect, in which impurities having high ionicity in a silica powder can be removed in a short time, an apparatus thereof, and a purified silica powder. A purification method of a silica powder comprises making a silica powder into a fluid state; contacting a purified gas to the silica powder in the fluid state at high temperature; and thereby removing impurity components of the silica powder. In the method, the silica powder in the fluid state is positioned in a magnetic field region. Further, the silica powder is contacted with the purified gas, while applying voltage to the silica powder by an electric field generated by moving of the silica powder. Preferably, the silica powder in a fluid state is positioned in the magnetic region of 10 gausses or more, and contacted with the purification gas at a temperature of I000&#xb0; C. or more.

Method for purification of silica particles, purifier, and purified silica particles

A method of producing a quartz glass crucible by arc melting a quartz powder molded product loaded on the inner side of a mold while performing vacuum suction, includes initiating the melting of quartz powder from the rim edge of a quartz powder molded product, subsequently lowering the arc electrode or raising the mold to heat and melt the sections on the downside of the rim edge. The method is preferably carried out such that the inner surface of the crucible is sealed within a time corresponding to 10% of the total arc time starting from the initiation of arc melting, and the seal thickness is 3 mm or less. The quartz glass crucible thus produced is useful for the pulling up of silicon single crystals and has a uniform glass layer with fewer internal bubbles.

Method for producing quartz glass crucible

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.

Method and apparatus for manufacturing vitreous silica crucible

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&#xb0; 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.

A silica glass crucible causing fewer pinholes in silicon single crystals is provided by a method of preventing pinholes by performing the pulling up of a silicon single crystal while restraining the dissolution rate of the crucible inner surface to 20 &#x3bc;m/hr or less, using a silica glass crucible for the pulling up of silicon single crystals, wherein the area of crystalline silica formed by crystallization of amorphous silica is restricted to 10% or less of the crucible inner surface area, or the density of pits formed from open bubbles on the crucible inner surface is restricted to 0.01 to 0.2 counts/mm.

Silica glass crucible and method for pulling up silicon single crystal using the same

A vitreous silica crucible for pulling single-crystal silicon, which is formed of vitreous silica and has a bottomed cylindrical shape, wherein, in a liquid-level movement range in the inner surface of the crucible, ranging from a position corresponding to the liquid surface level of a silicon melt at the time of stating the pulling of single-crystal silicon to a position corresponding to the liquid surface level of a silicon melt at the time of finishing the pulling of single-crystal silicon, the concentration of an OH group included in the vitreous silica is higher in an erosion thickness portion of the inner surface of the crucible than that in the range lower than the liquid surface level which is positioned below the liquid-level movement range.

Vitreous silica crucible for pulling single-crystal silicon

The method of producing a vitreous silica crucible, comprises deposition step of depositing silica powder on an inner wall surface of a cylindrical rotation mold having a bottom while rotating the mold; and a fusion step to obtain a vitreous silica crucible by heating and fusing the silica powder deposited on the inner wall surface of the mold and thereby vitrifying the silica powder. In the deposition step, a density of the deposited silica powder layer on the inner wall surface of the mold is controlled within a predetermined range by controlling the electrostatic charging voltage of the silica powder to be in a range of 1.0 kV or less in absolute value, and supplying the thus controlled silica powder to the inner wall surface of the mold. Thus, a wall thickness of the vitreous silica crucible is controlled.

Method of producing vitreous silica crucible

To provide a treatment method having excellent purification effect, in which impurities having high ionicity in a silica powder can be removed in a short time, a apparatus thereof, and a purified silica powder. A purification method of a silica powder comprises: making a silica powder into a fluid state; contacting a purified gas to the silica powder in the fluid state at high temperature; and thereby removing impurity components of the silica powder. In the method, the silica powder in the fluid state is positioned in a magnetic field region. Further, the silica powder is contacted with the purified gas, while applying voltage to the silica powder by an electric field generated by moving of the silica powder. Preferably, the silica powder in a fluid state is positioned in the magnetic region of 10 gausses or more, and contacted with the purification gas at a temperature of 1000&#xb0; C. or more.

A evaluation process of a vibration level at the surface of silicon melt held in a silica glass crucible is provided by setting in the vacuum furnace, the test piece of the silica glass cut out from a silica glass crucible, melting a little amount of silicon put on said piece of the glass, and measuring a vibration cycle of the silicon melt. Moreover, a silica glass crucible not causing the vibration at the surface of the silicon melt held in the silica glass crucible is also provided, wherein the vibration cycle of a silica glass of a side wall of the crucible is controlled at more than &#x2159; seconds.

Evaluation process of reactivity of silica glass with silicon melt and vibration at its surface, and silica glass crucible not causing the surface vibration

Growing community of inventors

Akita, Japan

Minoru Kanda