Shin-etsu Handotai Co., Ltd.

Michiaki Oda

Koji Mizuishi

Naoki Nagai

Isamu Harada

Seiichiro Ohtsuka

Chihiro Tashiro

Masahiko Urano

Yasushi Nakamura

Shiniti Sugai

Eiichi Iino

Fumio Yamada

Atsushi Iwasaki

Atsushi Ozaki

Yoshihiro Hirano

Toshinari Murai

Kouzou Yokota

Tadashi Niwayama

Masaru Toyoshima

Eizi Namiki

Shiniti Kon

Atsushi Shiozawa

Masahiro Mashimo

Tooru Ohara

Apparatus for measuring the mechanical strength of a neck portion of a silicon seed crystal used for growing a silicon crystal by the Czochralski method includes a seed chuck for holding the seed crystal of a test sample and an end of a wire hung from an upper hook. A crystal holder which holds the other end part of the test sample from below is tied to a lower hook with another wire to support the holder. The apparatus includes means for pulling the hook at a given rate, and measuring means for continuously measuring tensile load. Such apparatus and the method thereby provide accurate measurement of mechanical strength of the neck portion of the silicon seed crystal with good precision and reproducibility. A single crystal ingot is grown under conditions affording good balance of productivity and safety.

Apparatus and method for measuring mechanical strength of neck portion

In a pulling apparatus operated according to the multi-pulling method or CCZ method, granular silicon material is first fed to a feed pipe from a feeder so as to form stagnation of the granular silicon material in the feed pipe. The feeding of the granular silicon material from the feeder to the feed pipe is repeatedly commenced and stopped so as to maintain the stagnation of the granular silicon material. The feed rate of the granular silicon material from the feeder to the feed pipe is increased with time until the feed of the silicon material is completed. This prevents abrasion of a coating or lining provided on the inner surface of the feeder and also prevents damage of the feeder. In a pulling apparatus operated according to the Czochralski method, after causing granular silicon material to stagnate in the feed pipe, the crucible is lowered or the feed pipe is raised, while the stagnation of the granular silicon material is maintained, so as to form an unmolten layer of the granular silicon material on the molten or solidified surface of the silicon melt. The unmolten layer is then melted, and the granular silicon material is fed onto the unmolten layer through the feed pipe while the stagnation of the granular silicon material in the feed pipe is maintained. Accordingly, silicon material can be recharged without damaging the crucible, so that productivity and manufacturing yield of silicon monocrystals can be improved.

Method for feeding granular silicon material, feed pipe used in the

A silicon monocrystal is manufactured according to the continuously charged Czochralski method in which a double crucible is used which includes an outer crucible and an inner crucible which communicate with each other through pores. A dopant is charged to the silicon melt stored in the double crucible before commencing pulling of a silicon monocrystal such that the ratio of the dopant concentration of the silicon melt stored in the outer crucible to the dopant concentration of the silicon melt stored in the inner crucible becomes greater than an effective segregation coefficient of the dopant. The silicon monocrystal is then pulled while silicon material is charged to the silicon melt within the outer crucible, during which the dopant concentration ratio becomes equal to the effective segregation coefficient and then becomes smaller than the effective segregation coefficient. When the dopant concentration ratio becomes smaller than the effective segregation coefficient, the dopant is charged to the silicon melt stored in the outer crucible. The above operation is repeated, so that the specific resistance of the silicon monocrystal pulled from the double crucible can be controlled within a desired range using commonly-employed dopant.

Method of manufacturing silicon monocrystal by continuously charged

A method for cleaning and drying crucibles for use in pulling single crystals by the Czochralski method after transportation of the crucibles, includes cleaning a crucible in a cleaning process; warming the crucible with pure water heated at a temperature of at least 50.degree. C.; and drying the warmed crucible under ambient conditions.

Cleaning method of crucible

A feeding reservoir 11 for intermittently or continuously feeding granular raw material into a pulling apparatus 1, a chamber 13 connected to the feeding reservoir 11 through a gate valve 12, a granular raw material supply section 15 by which the granular raw material is supplied to the chamber 13 through a gate valve 14 and a pressure adjustment means 20 which adjusts the inner pressure of the chamber 13 is provided, and the granular raw material is fed to the feeding reservoir 11 while maintaining the inner pressure of the feeding reservoir 11 as the same as the inner pressure of the single crystal pulling apparatus 1. This feeding method and structure makes it possible to feed an additional amount of granular raw material even during the continuous charging process and or the recharging process without interrupting the process and also to pull a heavy single crystal rod with a large diameter without increasing the capacity of the feeding reservoir.

Method for feeding a granular raw material and feeding apparatus

A recharger system including a feeder and a feed conduit recharge polycrystalline silicon granules into a crucible after a run or operation of growing a single crystal silicon rod by the Czochralski method, thereby to prepare for a next run of crystal growing. The amount of holdup or backed-up supply of the silicon granules in the feed conduit is detected by a sensor provided on the feed conduit. A smooth and high-rate feed of the silicon granules is ensured by controlling the feed rate of the silicon granules from the feeder to the feed conduit and/or a descending velocity of the crucible by signals generated in the sensor as a function of the amount of the holdup or backed-up supply in the feed conduit.

Apparatus for recharging of silicon granules in a czochralski single

An automatic metering/supplying apparatus is used for subdividing a granular silicon material. A cone member is placed on the upper opening portion of a drum, which contains the granular silicon material, so as to hold the drum. Subsequently, the drum is turned upside down by a rotary-type drum-inverting machine. Meanwhile, a quartz recharge tube into which the granular silicon material is to be discharged is placed on an electronic scale so as to measure the amount of the silicon material supplied to the quartz recharge tube. A valve control unit opens the valve to start the supply of the silicon material and closes the valve when the measured weight reaches a predetermined weight. Dust produced in the vicinity of the valve is sucked by a dust collection mechanism. The automatic metering/supplying apparatus can automate work for subdividing the granular silicon material contained in the drum. Further, collection of dust maintains the working environment clean.

Automatic metering/supplying apparatus for granular substances

In a method of manufacturing a silicon monocrystal using a continuous Czochralski method, a silicon monocrystal is pulled from a silicon melt in a crucible while a silicon material is fed to the crucible. Supply of the silicon material is suspended until the temperature distribution of the silicon melt becomes stable after initiation of a straight body forming process, and the supply of the silicon material is commenced when the temperature distribution of the silicon melt has become stable. The feed rate of the silicon material is gradually increased until the feed rate becomes equal to a solidification rate of the silicon melt after the supply of the silicon material has been commenced. This method prevents the silicon monocrystal from becoming a polycrystal during the manufacture thereof.

Method of manufacturing silicon monocrystal using continuous czochralski

Method for recharging of silicon granules in a Czochralski single

An apparatus for producing a semiconductor single-crystal grown by the Czochralski method includes a reference reflector disposed at the lower end of a gas rectifying tube, first and second optical systems disposed above the reference reflector for changing the direction of propagation of light from the horizontal to the vertical, and vice versa, a first position sensor composed of a first light source for emitting a light beam in a horizontal direction toward the first optical system, and a first photosensitive member which receives a reflection light reflected from the melt surface in a crucible, a second position sensor composed of a second light source for emitting a light beam in a horizontal direction toward the second optical system, and a second photosensitive member which receives a reflection light reflected from the reference reflector. With this construction, the distance between the gas rectifying tube and the melt surface can be detected and maintained constant throughout the crystal growth process with the result that the crystal quality, especially the concentration of dopant and impurities, such as oxygen and carbon, is uniform.

Method and apparatus for producing a Czochralski growth semiconductor

A single crystal pulling apparatus of the Czochralski method type wherein the cylindrical heater is supported not only by the two existing electrodes which are vertically shiftable but also by one or more vertical shafts, which may be electrodes or electrically insulated dummy electrodes; the vertical shafts are capable of shifting vertically in synchronism with the existing two electrodes, and are arranged in a manner such that the existing two electrodes and the vertical shafts are at regular intervals along the bottom circumference of the cylindrical heater.

Single crystal pulling apparatus

Aa single crystal pulling apparatus installed on a frame body further includes a second frame body which is founded independently from the main chamber to rigidly support the winder assembly, and a hermetical and flexible tube which is provided between the winder assembly and the pull chamber to prevent any stress and vibration from travelling from the winder assembly to the pull chamber and vice versa, while providing a communication passage between the winder assembly and the pull chamber.

An apparatus for producing a single crystal grown by Czochralski method includes a winding drum disposed in a case for winding up and down a flexible pull wire, a power transmission mechanism for driving the winding drum, and a bearing unit for rotatably supporting the winding drum. The power transmission mechanism and the bearing unit are disposed outside the case and isolated from the furnace atmosphere surrounding the winding drum and the pull wire in the case. With this construction, metallic dust produced by abrasion from the power transmission mechanism and the bearing unit has no influence on the condition of the furnace atmosphere and hence the quality of a single crystal being pulled upwardly by the pull wire.

Apparatus for producing Czochralski-grown single crystals

A single crystal pulling apparatus having a wire which is used to pull a crystal is provided with a novel wire vibration prevention mechanism. The wire vibration prevention mechanism includes wire restriction devices which restrict the movement of the wire to movement in the vertical direction. The wire restriction devices may be mechanically driven in the horizontal direction in order to center the pulled crystal. The wire restriction devices are driven by pneumatic air cylinders. Use of the wire vibration prevention mechanism avoids the formation of deformed growth of the pulled crystal and thus reduces the occurrence of dislocations in the pulled crystal.

Wire vibration prevention mechanism for a single crystal pulling

An isolation valve used in a single crystal pulling apparatus, having a frame (11), a vertical passageway for communication between a main chamber and an upper pull chamber of the single crystal pulling apparatus, a shaft (13) capable of turning about its axis and reciprocating vertically, a lever (20) for turning the shaft, a drive means (18) for reciprocating the shaft (13), an arm (14) fixed to the shaft (13), a circular shutter (15) held by the arm (14) for closing and opening the vertical passageway, and a flange (9) defining a hole which communicates the passageway with the main chamber, wherein a cylindrical cavity is made in the bottom of the circular shutter (15); the flange (9) has a circular raised rim (9b) extending upward whose outer diameter is slightly smaller than the diameter of the cylindrical cavity of the shutter; and an endless circular seal means (17) is embedded partially in either the external vertical wall of the raised rim (9b) of the flange or the internal vertical wall of the shutter (15).

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Annaka, Japan

Michiaki Oda