Patents by Inventor Izumi Fusegawa
Izumi Fusegawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20070101926Abstract: The present invention is a method of manufacturing a silicon single crystal by Czochralski method without performing Dash Necking method, comprising the steps of: providing a seed crystal having a tip end with a sharp-pointed shape or a truncation thereof in which an angle of the tip end is 28° or less; keeping the tip end of the seed crystal at just above a silicon melt to heat it before bringing the tip end of the seed crystal into contact with the silicon melt; bringing the tip end of the seed crystal into contact with the silicon melt and immersing the seed crystal into the silicon melt to a desired diameter; and shifting to pull the single crystal, wherein a temperature variation at a surface of the silicon melt is kept at ±5° C. or less at least for a period from a point of bringing the tip end of the seed crystal into contact with the silicon melt to a point of shifting to pull the single crystal.Type: ApplicationFiled: January 4, 2007Publication date: May 10, 2007Applicant: Shin-Etsu Handotai Co., Ltd.Inventors: Izumi FUSEGAWA, Sadayuki Okuni, Nobuaki Mitamura, Tomohiko Ohta, Nobuo Katuoka
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Patent number: 7214268Abstract: The present invention is a method of producing a P(phosphorus)-doped silicon single crystal by Czochralski method, wherein, at least, a growth of the single crystal is performed so that an Al (aluminum) concentration is 2×1012 atoms/cc or more. Thereby, there can be provided a method of easily and inexpensively producing a P(phosphorus)-doped silicon single crystal of defect-free region having an excellent capability of electrical characteristics to be high breakdown voltage, which contains neither, for example, V region, OSF region, nor large dislocation cluster (LSEPD, LFPD) region.Type: GrantFiled: December 25, 2003Date of Patent: May 8, 2007Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Masahiro Sakurada, Izumi Fusegawa
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Patent number: 7179330Abstract: The present invention is a method of manufacturing a silicon single crystal by Czochralski method without performing Dash Necking method, wherein a temperature variation at a surface of a silicon melt is kept at ±5° C. or less at least for a period from a point of bringing the tip end of a seed crystal into contact with the silicon melt to a point of shifting to pull the single crystal. Thereby, in a method of growing a silicon single crystal by Czochralski method without using Dash Necking method, a success ratio of growing a single crystal free from dislocation can be increased, at the same time a heavy silicon single crystal having a large diameter in which a diameter of a constant diameter portion is over 200 mm can be grown even in the case of growing a silicon single crystal having a crystal orientation of <110>.Type: GrantFiled: April 23, 2003Date of Patent: February 20, 2007Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Izumi Fusegawa, Sadayuki Okuni, Nobuaki Mitamura, Tomohiko Ohta, Nobuo Katuoka
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Patent number: 7129123Abstract: In a method for producing an SOI wafer comprising steps of implanting ions from a bond wafer surface to form an ion-implanted layer inside the wafer, bonding the ion-implanted bond wafer surface and a surface of a base wafer via an oxide film or directly, and forming an SOI wafer by delaminating by heat treatment a part of the bond wafer at the ion-implanted layer, the bond wafer is a silicon wafer that consists of a silicon single crystal grown by Czochralski method, that is occupied by N region outside OSF generated in a ring shape and that has no defect region detected by Cu deposition method. Thereby, even an extremely thin SOI layer having a thickness of 200 nm or less, can provide an SOI wafer that has an excellent electric property without micro pits caused by acid cleaning, and can be produced without increasing the number of processes.Type: GrantFiled: October 24, 2003Date of Patent: October 31, 2006Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Masahiro Sakurada, Nobuaki Mitamura, Izumi Fusegawa, Tomohiko Ohta
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Publication number: 20060236919Abstract: The present invention is a method for producing a single crystal in accordance with Czochralski method by flowing an inert gas downward in a chamber 1 of a single crystal-pulling apparatus 11 and surrounding a single crystal 3 pulled from a raw material melt 2 with a gas flow-guide cylinder 4, wherein when a single crystal within N region outside OSF region generated in a ring shape in the radial direction of the single crystal is pulled, the single crystal within N region is pulled in a condition that flow amount of the inert gas between the single crystal and the gas flow-guide cylinder is 0.6 D(L/min) or more and pressure in the chamber is 0.6 D(hPa) or less, in which D (mm) is a diameter of the single crystal to be pulled. It is preferable that there is used the gas flow-guide cylinder that Fe concentration is 0.05 ppm or less, at least, in a surface thereof.Type: ApplicationFiled: August 13, 2004Publication date: October 26, 2006Applicant: Shin-Etsu Handotai Co., Ltd.Inventors: Izumi Fusegawa, Nobuaki Mitamuria, Takahiro Yanagimachi
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Publication number: 20060174819Abstract: The present invention is a method for producing a single crystal of which a whole plane in a radial direction is a defect-free region with pulling the single crystal from a raw material melt in a chamber by Czochralski method, wherein a pulling condition is changed in a direction of the crystal growth axis during pulling the single crystal so that a margin of a pulling rate is always a predetermined value or more that the single crystal of which the whole plane in a radial direction is a defect-free region can be pulled. Thereby, there can be provided a method for producing a single crystal in which when a single crystal is produced by CZ method, the single crystal of which a whole plane in a radial direction is a defect-free region entirely in a direction of the crystal growth axis can be produced with stability.Type: ApplicationFiled: May 27, 2004Publication date: August 10, 2006Applicant: SHIN-ETSU HANDOTAI CO., LTD.Inventors: Nobuaki Mitamura, Tomohiko Ohta, Izumi Fusegawa, Masahiro Sakurada, Atsushi Ozaki
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Publication number: 20060113594Abstract: An SOI wafer in which a base wafer and a bond wafer respectively consisting of silicon single crystal are bonded via an oxide film, and then the bond wafer is thinned to form a silicon active layer, wherein the base wafer is formed of silicon single crystal grown by Czochralski method, and the whole surface of the base wafer is within N region outside OSF region and doesn't include a defect region detected by Cu deposition method, or the whole surface of the base wafer is within a region outside OSF region, doesn't include a defect region detected by Cu deposition method, and includes I region containing dislocation cluster due to interstitial silicon. Thereby, there is provided an SOI wafer that retains high insulating properties and has an excellent electrical reliability in device fabrication even in the case of forming an extremely thin interlevel dielectric oxide film with, for example, a thickness of 100 nm or less.Type: ApplicationFiled: January 22, 2004Publication date: June 1, 2006Applicant: SHIN-ETSU HANDOTAI CO., LTD.Inventors: Masahiro Sakurada, Nobuaki Mitamura, Izumi Fusegawa
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Process for producing p doped silicon single crystal and p doped n type silicon single crystal wafer
Publication number: 20060065184Abstract: The present invention is a method of producing a P(phosphorus)-doped silicon single crystal by Czochralski method, wherein, at least, a growth of the single crystal is performed so that an Al (aluminum) concentration is 2×1012 atoms/cc or more. Thereby, there can be provided a method of easily and inexpensively producing a P(phosphorus)-doped silicon single crystal of defect-free region having an excellent capability of electrical characteristics to be high breakdown voltage, which contains neither, for example, V region, OSF region, nor large dislocation cluster (LSEPD, LFPD) region.Type: ApplicationFiled: December 25, 2003Publication date: March 30, 2006Inventors: Masahiro Sakurada, Izumi Fusegawa -
Publication number: 20050252441Abstract: In a method for producing a silicon single crystal by Czochralski method, the single crystal is grown with controlling a growth rate between a growth rate at a boundary where a defect region detected by Cu deposition remaining after disappearance of OSF ring disappears when gradually decreasing a growth rate of silicon single crystal during pulling and a growth rate at a boundary where a high oxygen precipitation Nv region having a density of BMDs of 1×107 numbers/cm3 or more and/or a wafer lifetime of 30 ?sec or less after oxygen precipitation treatment disappears when gradually decreasing the growth rate further. Thereby, there is provided a silicon single crystal which does not belong to any of V region rich in vacancy, OSF region and I region rich in interstitial silicon, and has excellent electrical characteristics and gettering capability, so that yield of devices can be surely improved, and also an epitaxial wafer.Type: ApplicationFiled: May 7, 2003Publication date: November 17, 2005Inventors: Masahiro Sakurada, Nobuaki Mitamura, Izumi Fusegawa, Tomohiko Ohta
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Publication number: 20050205004Abstract: The present invention discloses a graphite heater for producing a single crystal used when producing a single crystal by the Czochralski method which comprises at least a terminal part to which electric current is supplied and a cylindrical heat generating part by resistance heating and are provided so as to surround a crucible for containing a raw material melt wherein the heat generating part has heat generating slit parts formed by being provided with upper slits extending downward from the upper end and lower slits extending upwards from the lower end by turns, and a length of at least one slit of the upper slits differs from others and/or a length of at least one slit of the lower slits differs from others so that a heat generating distribution of the heat generating part may be changed.Type: ApplicationFiled: December 8, 2003Publication date: September 22, 2005Inventors: Masahiro Sakurada, Izumi Fusegawa, Satoshi Soeta, Makoto Iida
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Publication number: 20050160966Abstract: The present invention is a method of manufacturing a silicon single crystal by Czochralski method without performing Dash Necking method, wherein a temperature variation at a surface of a silicon melt is kept at ±5° C. or less at least for a period from a point of bringing the tip end of a seed crystal into contact with the silicon melt to a point of shifting to pull the single crystal.Type: ApplicationFiled: April 23, 2003Publication date: July 28, 2005Applicant: SHIN-ETSU HANDOTAI CO., LTDInventors: Izumi Fusegawa, Sadayuki Okuni, Nobuaki Mitamura, Tomohiko Ohta, Nobuo Katuoka
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Patent number: 6913646Abstract: There can be provided a silicon single crystal wafer grown according to Czochralski method wherein the whole plane of the wafer is occupied by N region on the outside of OSF generated in a shape of a ring by thermal oxidation treatment and there exists no defect region detected by Cu deposition. Thereby, there can be produced a silicon single crystal wafer according to CZ method, which does not belong to any of V region rich in vacancies, OSF region and I region rich in interstitial silicons, and can surely improve electric characteristics such as oxide dielectric breakdown voltage characteristics or the like under stable manufacture conditions.Type: GrantFiled: December 26, 2001Date of Patent: July 5, 2005Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Masahiro Sakurada, Takeshi Kobayashi, Tatsuo Mori, Izumi Fusegawa, Tomohiko Ohta
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Patent number: 6893499Abstract: According to the present invention, there is disclosed a silicon single crystal wafer grown according to the CZ method which is a wafer having a diameter of 200 mm or more produced from a single crystal grown at a growth rate of 0.5 mm/min or more without doping except for a dopant for controlling resistance, wherein neither an octahedral void defect due to vacancies nor a dislocation cluster due to interstitial silicons exists as a grown-in defect, and a method for producing it.Type: GrantFiled: June 28, 2001Date of Patent: May 17, 2005Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Izumi Fusegawa, Koji Kitagawa, Ryoji Hoshi, Masahiro Sakurada, Tomohiko Ohta
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Publication number: 20050064632Abstract: In a method for producing an SOI wafer comprising steps of implanting hydrogen ions etc. from a surface of a bond wafer 21 to form an ion-implanted layer 24 inside the wafer, bonding the ion-implanted surface of the bond wafer and a surface of a base wafer 22 via an oxide film 23 or directly, and forming an SOI wafer by delaminating a part of the bond wafer at the ion-implanted layer by heat treatment, wherein a silicon wafer consisting of silicon single crystal grown by Chochralski method, which is occupied by N region outside OSF generated in a ring shape and has no defect region detected by Cu deposition method, is used as the bond wafer. Thereby, even in the case of forming an extremely thin SOI layer 27 such that, for example, its thickness is 200 nm or less, there is provided an SOI wafer which has an excellent electric property without causing micro pits by cleaning with hydrofluoric acid etc., and in addition, can be produced without increasing the number of process.Type: ApplicationFiled: October 24, 2003Publication date: March 24, 2005Inventors: Masahiro Sakurada, Nobuaki Mitamura, Izumi Fusegawa, Tomohiko Ohta
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Patent number: 6764548Abstract: The present invention provides an apparatus and a method for producing a silicon semiconductor single crystal which can stabilize and homogenize an amount of precipitated oxygen in the direction of the crystal growth axis when growing a silicon semiconductor single crystal. The apparatus for producing a silicon semiconductor single crystal by the Czochralski method comprises a main growth furnace having a crucible retaining silicon melt disposed therein for growing a silicon semiconductor single crystal, and an upper growth furnace for housing therein and cooling the silicon semiconductor single crystal pulled from the silicon melt, wherein the upper growth furnace communicated to a ceiling section of the main growth furnace is provided with an upper insulating member for surrounding a pulled silicon semiconductor single crystal.Type: GrantFiled: August 20, 2002Date of Patent: July 20, 2004Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Ryoji Hoshi, Takahiro Yanagimachi, Izumi Fusegawa, Tomohiko Ohta, Yuuichi Miyahara, Tetsuya Igarashi
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Patent number: 6632411Abstract: The present invention provides a silicon wafer sliced from a silicon single crystal ingot grown by the Czochralski method under such conditions that V-rich region should become dominant, wherein count number of particles having a size of 0.1 &mgr;m or more is 1 count/cm2 or less when particles are counted by using a particle counter and a method for producing a silicon single crystal. Thus, there is provided a production technique that can improve productivity and reduce cost for high quality silicon wafers of excellent device characteristics by further reducing density and size of defects such as COP.Type: GrantFiled: November 23, 2001Date of Patent: October 14, 2003Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Ryoji Hoshi, Izumi Fusegawa, Tomohiko Ohta, Shigemaru Maeda
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Patent number: 6632280Abstract: An apparatus for growing a single crystal (20) comprising at least a main chamber (1) enclosing a crucible (5, 6) for accommodating a raw material melt (4) and a heater (7) for heating the raw material melt and a pulling chamber (2) continuously provided above the main chamber, into which a grown single crystal is pulled and stored, wherein the apparatus further comprises a cooling cylinder (11) that extends at least from a ceiling of the main chamber toward a raw material melt surface so as to surround a single crystal under pulling (3) and is forcibly cooled with a cooling medium, and an auxiliary cooling member (13) extending below the cooling cylinder and having a cylindrical shape or a shape tapered toward the downward direction. There is provided an apparatus for growing a single crystal that can exert cooling effect on a grown single crystal to the maximum extent so as to accelerate the crystal growth rate and safely produce a single crystal without leakage of cooling medium due to breakage etc.Type: GrantFiled: September 21, 2001Date of Patent: October 14, 2003Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Ryoji Hoshi, Koji Kitagawa, Izumi Fusegawa, Tomohiko Ohta
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Patent number: 6592662Abstract: In a method manufacturing a silicon single crystal 8 according to an MCZ method, a flow rate of an inert gas flowing in a growth furnace 1 during growth of the silicon single crystal 8 and/or a pressure in the growth furnace 1 is altered according to a pulling amount of the silicon single crystal 8 to adjust an interstitial oxygen concentration therein. By altering a flow rate of an inert gas flowing in the growth furnace or a pressure therein, an amount of oxygen evaporating as an oxide from a surface of a silicon melt 10 in the vicinity of a crystal growth interface can be easily adjusted, and thereby, an oxygen amount included in the silicon melt 10 can be controlled with ease.Type: GrantFiled: October 24, 2001Date of Patent: July 15, 2003Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Izumi Fusegawa, Ryoji Hoshi, Kouichi Inokoshi, Tomohiko Ohta
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Publication number: 20030116082Abstract: There can be provided a silicon single crystal wafer grown according to Czochralski method wherein the whole plane of the wafer is occupied by N region on the outside of OSF generated in a shape of a ring by thermal oxidation treatment and there exists no defect region detected by Cu deposition. Thereby, there can be produced a silicon single crystal wafer according to CZ method, which does not belong to any of V region rich in vacancies, OSF region and I region rich in interstitial silicons, and can surely improve electric characteristics such as oxide dielectric breakdown voltage characteristics or the like under stable manufacture conditions.Type: ApplicationFiled: August 27, 2002Publication date: June 26, 2003Inventors: Masahiro Sakurada, Takeshi Kobayashi, Tatsuo Mori, Izumi Fusegawa, Tomohiko Ohta
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Publication number: 20030106484Abstract: According to the present invention, there is disclosed a silicon single crystal wafer grown according to the CZ method which is a wafer having a diameter of 200 mm or more produced from a single crystal grown at a growth rate of 0.5 mm/min or more without doping except for a dopant for controlling resistance, wherein neither an octahedral void defect due to vacancies nor a dislocation cluster due to interstitial silicons exists as a grown-in defect, and a method for producing it.Type: ApplicationFiled: December 26, 2002Publication date: June 12, 2003Inventors: Izumi Fusegawa, Koji Kitagawa, Ryoji Hoshi, Masahiro Sakurada, Tomohiko Ohta