Patents by Inventor Tatsumi Kusaba
Tatsumi Kusaba 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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Patent number: 8003494Abstract: In a method for producing a bonded wafer by bonding a wafer for active layer and a wafer for support layer and thinning the wafer for active layer according to the invention, oxygen ions are implanted into the wafer for active layer at a state of holding a temperature of the wafer for active layer below 200° C. under a dose of 5×1015 to 5×1016 atoms/cm2, whereby there can be obtained a bonded wafer being excellent in the thickness uniformity after thinning and having a dramatically improved surface roughness.Type: GrantFiled: August 6, 2008Date of Patent: August 23, 2011Assignee: SUMCO CorporationInventors: Hideki Nishihata, Nobuyuki Morimoto, Tatsumi Kusaba, Akihiko Endo
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Patent number: 7939441Abstract: This p-type silicon wafer was subjected to heat treatment to have a resistivity of 10 ?·cm or more, a BMD density of 5×107 defects/cm3 or more, and an n-type impurity concentration of 1×1014 atoms/cm3 or less at a depth of within 5 ?m from a surface of the wafer. This method for heat-treating p-type silicon wafers, the method includes the steps of: loading p-type silicon wafers onto a wafer boat, inserting into a vertical furnace, and holding in an argon gas ambient atmosphere at a temperature of 1100 to 1300° C. for one hour; moving the wafer boat to a transfer chamber and discharging the silicon wafers; and transferring to the wafer boat silicon wafers to be heat treated next, wherein after the discharge of the heat-treated silicon wafers, the silicon wafers to be heat-treated next are transferred to the wafer boat within a waiting time of less than two hours.Type: GrantFiled: April 21, 2009Date of Patent: May 10, 2011Assignee: Sumco CorporationInventors: Tatsumi Kusaba, Hidehiko Okuda
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Patent number: 7927957Abstract: A bonded silicon wafer is produced by a method including an oxygen ion implantation step on a silicon wafer for active layer having the specified wafer face; a step of bonding the silicon wafer for active layer to a silicon wafer for support; a first heat treatment step; an inner SiO2 layer exposing step; a step of removing the inner SiO2 layer; and a planarizing step of polishing a silicon wafer composite or subjecting the silicon wafer composite to a heat treatment in a reducing atmosphere (a second heat treatment step).Type: GrantFiled: September 11, 2009Date of Patent: April 19, 2011Assignee: SUMCO CorporationInventors: Tatsumi Kusaba, Akihiko Endo, Hideki Nishihata, Nobuyuki Morimoto
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Patent number: 7927972Abstract: Even if an oxygen ion implanted layer in a wafer for active layer is not a completely continuous SiO2 layer but a layer mixed partially with Si or SiOx, it is removed by here is provided a method for producing a bonded wafer in which it is possible to remove an oxygen ion implanted layer effectively as it is by repetitive treatment with an oxidizing solution and HF solution at a step of removing the oxygen ion implanted layer in a bonded wafer.Type: GrantFiled: April 9, 2009Date of Patent: April 19, 2011Assignee: Sumco CorporationInventors: Akihiko Endo, Tatsumi Kusaba
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Publication number: 20100248447Abstract: In a method for producing a bonded wafer by bonding a wafer for active layer and a wafer for support layer and thinning the wafer for active layer according to the invention, oxygen ions are implanted into the wafer for active layer at a state of holding a temperature of the wafer for active layer below 200° C. under a dose of 5×1015 to 5×1016 atoms/cm2, whereby there can be obtained a bonded wafer being excellent in the thickness uniformity after thinning and having a dramatically improved surface roughness.Type: ApplicationFiled: August 6, 2008Publication date: September 30, 2010Applicant: Sumco CorporationInventors: Hideki Nishihata, Nobuyuki Morimoto, Tatsumi Kusaba, Akihiko Endo
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Patent number: 7767549Abstract: The present invention provides a method of manufacturing a bonded wafer. The method comprises an oxidation step in which an oxide film is formed on at least one surface of a base wafer, a bonding step in which the base wafer on which the oxide film has been formed is bonded to a top wafer to form a bonded wafer, and a thinning step in which the top wafer included in the bonded wafer is thinned. The oxidation step comprises heating the base wafer to a heating temperature ranging from 800 to 1300° C. at a rate of temperature increase ranging from 1 to 300° C./second in an oxidizing atmosphere, and the bonding step is carried out so as to position the oxide film formed in the oxidation step at an interface of the top wafer and the base wafer.Type: GrantFiled: December 17, 2007Date of Patent: August 3, 2010Assignee: Sumco CorporationInventors: Hidehiko Okuda, Tatsumi Kusaba, Akihiko Endo
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Patent number: 7763541Abstract: There is provided a layer transferred wafer subjected to a process for regenerating to be reused many times for an SOI layer wafer which is used to manufacture an SOI wafer with an excellent process yield in which oxygen precipitate nuclei or oxygen precipitates are eliminated and generation of HF defects are inhibited by performing the process for regenerating the layer transferred wafer generated as a by-product by an ion implantation separation method. The process for regenerating a layer transferred wafer in which the layer transferred wafer 11b obtained as a by-product in manufacturing a bonded SOI wafer 10 by an ion implantation separation method so as to be reused for an SOI layer wafer 11 of the bonded SOI wafer 10, comprises: rapidly heating the layer transferred wafer 11b in an oxidizing atmosphere, then holding it for a fixed time and subsequently rapidly cooling it; and mirror-polishing a surface of the layer transferred wafer 11b.Type: GrantFiled: November 28, 2006Date of Patent: July 27, 2010Assignee: Sumco CorporationInventors: Hidehiko Okuda, Akihiko Endo, Tatsumi Kusaba
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Publication number: 20100184270Abstract: A bonded wafer is produced by comprising a step of implanting oxygen ions from a surface of a wafer for active layer to form an oxygen ion implanted layer at a given position inside the wafer for active layer; a step of bonding the wafer of active layer to a wafer for support substrate directly or through an insulating film; a step of subjecting the resulting bonded wafer to a heat treatment for increasing a bonding strength; a step of removing a portion of the wafer for active layer in the bonded wafer to a given position not exposing the oxygen ion implanted layer by a given method; a step of exposing the entire surface of the oxygen ion implanted layer; and a step of removing the exposed oxygen ion implanted layer to obtain an active layer of a given thickness, wherein the step of exposing the entire surface of the oxygen ion implanted layer is carried out by a dry etching under given conditions.Type: ApplicationFiled: March 29, 2010Publication date: July 22, 2010Applicant: SUMCO CORPORATIONInventors: Akihiko Endo, Tatsumi Kusaba
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Patent number: 7745306Abstract: A bonded wafer is produced by a method comprising a step of implanting ions of a light element such as hydrogen, helium or the like into a wafer for active layer at a predetermined depth position to form an ion implanted layer, a step of bonding the wafer for active layer to a wafer for support substrate through an insulating film, a step of exfoliating the wafer at the ion implanted layer, a first heat treatment step of conducting a sacrificial oxidation for reducing damage on a surface of an active layer exposed through the exfoliation and a second heat treatment step of raising a bonding strength, in which the second heat treatment step is continuously conducted after the first heat treatment step without removing an oxide film formed on the surface of the active layer.Type: GrantFiled: July 20, 2007Date of Patent: June 29, 2010Assignee: Sumco CorporationInventors: Hidehiko Okuda, Tatsumi Kusaba
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Publication number: 20100144119Abstract: In the production of a bonded wafer, a wafer for active layer after a heat treatment for bonding reinforcement followed by bonding is thinned to a given thickness by a surface polishing or an etching and then a wafer for support layer is subjected to both a minor-surface beveling and a terrace processing simultaneously.Type: ApplicationFiled: December 4, 2009Publication date: June 10, 2010Applicant: SUMCO CORPORATIONInventors: Tatsumi Kusaba, Akihiko Endo
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Patent number: 7718509Abstract: A bonded wafer is produced by comprising a step of implanting oxygen ions from a surface of a wafer for active layer to form an oxygen ion implanted layer at a given position inside the wafer for active layer; a step of bonding the wafer of active layer to a wafer for support substrate directly or through an insulating film; a step of subjecting the resulting bonded wafer to a heat treatment for increasing a bonding strength; a step of removing a portion of the wafer for active layer in the bonded wafer to a given position not exposing the oxygen ion implanted layer by a given method; a step of exposing the entire surface of the oxygen ion implanted layer; and a step of removing the exposed oxygen ion implanted layer to obtain an active layer of a given thickness, wherein the step of exposing the entire surface of the oxygen ion implanted layer is carried out by a dry etching under given conditions.Type: GrantFiled: May 27, 2009Date of Patent: May 18, 2010Assignee: Sumco CorporationInventors: Akihiko Endo, Tatsumi Kusaba
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Publication number: 20100068867Abstract: A bonded silicon wafer is produced by a method comprising an oxygen ion implantation step on a silicon wafer for active layer having the specified wafer face; a step of bonding the silicon wafer for active layer to a silicon wafer for support; a first heat treatment step; an inner SiO2 layer exposing step; a step of removing the inner SiO2 layer; and a planarizing step of polishing a silicon wafer composite or subjecting the silicon wafer composite to a heat treatment in a reducing atmosphere (a second heat treatment step).Type: ApplicationFiled: September 11, 2009Publication date: March 18, 2010Applicant: SUMCO CORPORATIONInventors: Tatsumi Kusaba, Akihiko Endo, Hideki Nishihata, Nobuyuki Morimoto
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Publication number: 20090298261Abstract: A bonded wafer is produced by comprising a step of implanting oxygen ions from a surface of a wafer for active layer to form an oxygen ion implanted layer at a given position inside the wafer for active layer; a step of bonding the wafer of active layer to a wafer for support substrate directly or through an insulating film; a step of subjecting the resulting bonded wafer to a heat treatment for increasing a bonding strength; a step of removing a portion of the wafer for active layer in the bonded wafer to a given position not exposing the oxygen ion implanted layer by a given method; a step of exposing the entire surface of the oxygen ion implanted layer; and a step of removing the exposed oxygen ion implanted layer to obtain an active layer of a given thickness, wherein the step of exposing the entire surface of the oxygen ion implanted layer is carried out by a dry etching under given conditions.Type: ApplicationFiled: May 27, 2009Publication date: December 3, 2009Applicant: SUMCO CORPORATIONInventors: Akihiko Endo, Tatsumi Kusaba
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Publication number: 20090258475Abstract: Even if an oxygen ion implanted layer in a wafer for active layer is not a completely continuous SiO2 layer but a layer mixed partially with Si or SiOx, it is removed by here is provided a method for producing a bonded wafer in which it is possible to remove an oxygen ion implanted layer effectively as it is by repetitive treatment with an oxidizing solution and HF solution at a step of removing the oxygen ion implanted layer in a bonded wafer.Type: ApplicationFiled: April 9, 2009Publication date: October 15, 2009Applicant: SUMCO CORPORATIONInventors: Akihiko Endo, Tatsumi Kusaba
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Patent number: 7601227Abstract: A method for achieving high purity in a jig for semiconductor heat treatment includes subjecting a semiconductor heat treatment jig made of a substrate having a surface covered with a silicon carbide film grown by chemical vapor deposition or a semiconductor heat treatment jig made of a silicon carbide film grown by chemical vapor deposition to high-temperature oxidation heat treatment so as to form an oxide film on a surface of the silicon carbide film, and removing the oxide film.Type: GrantFiled: August 5, 2005Date of Patent: October 13, 2009Assignee: Sumco CorporationInventor: Tatsumi Kusaba
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Publication number: 20090233420Abstract: This p-type silicon wafer was subjected to heat treatment to have a resistivity of 10 ?·cm or more, a BMD density of 5×107 defects/cm3 or more, and an n-type impurity concentration of 1×1014 atoms/cm3 or less at a depth of within 5 ?m from a surface of the wafer. This method for heat-treating p-type silicon wafers, the method includes the steps of: loading p-type silicon wafers onto a wafer boat, inserting into a vertical furnace, and holding in an argon gas ambient atmosphere at a temperature of 1100 to 1300° C. for one hour; moving the wafer boat to a transfer chamber and discharging the silicon wafers; and transferring to the wafer boat silicon wafers to be heat treated next, wherein after the discharge of the heat-treated silicon wafers, the silicon wafers to be heat-treated next are transferred to the wafer boat within a waiting time of less than two hours.Type: ApplicationFiled: April 21, 2009Publication date: September 17, 2009Applicant: SUMCO CORPORATIONInventors: Tatsumi Kusaba, Hidehiko Okuda
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Patent number: 7541663Abstract: This p-type silicon wafer was subjected to heat treatment to have a resistivity of 10 ?·cm or more, a BMD density of 5×107 defects/cm3 or more, and an n-type impurity concentration of 1×1014 atoms/cm3 or less at a depth of within 5 ?m from a surface of the wafer. This method for heat-treating p-type silicon wafers, the method includes the steps of: loading p-type silicon wafers onto a wafer boat, inserting into a vertical furnace, and holding in an argon gas ambient atmosphere at a temperature of 1100 to 1300° C. for one hour; moving the wafer boat to a transfer chamber and discharging the silicon wafers; and transferring to the wafer boat silicon wafers to be heat treated next, wherein after the discharge of the heat-treated silicon wafers, the silicon wafers to be heat-treated next are transferred to the wafer boat within a waiting time of less than two hours.Type: GrantFiled: August 10, 2005Date of Patent: June 2, 2009Assignee: Sumco CorporationInventors: Tatsumi Kusaba, Hidehiko Okuda
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Patent number: 7534728Abstract: In the production process of an SOI substrate using a hydrogen ion implantation method, a process is provided for cleaning the substrate which can prevent formation of voids when bonding substrates and formation of blistering after exfoliation. In the process for cleaning, cleaning of the substrate is performed before performing hydrogen ion implantation. As the cleaning method, one or more of a combination selected from the group consisting of SC-1 cleaning, SC-1 cleaning+SC-2 cleaning, HF/O3 cleaning, and HF cleaning+O3 cleaning, can be used.Type: GrantFiled: April 12, 2006Date of Patent: May 19, 2009Assignee: Sumco CorporationInventors: Hideki Nishihata, Tatsumi Kusaba, Nobuyuki Morimoto
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Patent number: 7442623Abstract: A high quality bonded substrate is obtained in which generation of microprotrusions and cracked particles are restricted on a surface of an active layer of the bonded substrate and the surface of the active layer is flattened. A laminated body is formed by overlapping a first semiconductor substrate serving as an active layer onto a second semiconductor substrate serving as a support substrate via an oxide film or without an oxide film; the active layer is formed by forming a thin film from the first semiconductor substrate; and the surface of the active layer is flattened by vapor-phase etching. After forming a thin film from the first semiconductor substrate and before flattening the surface of the active layer by the vapor-phase etching, an organic substance adhering to the surface of the active layer is removed and a native oxide film generated on the surface of the active layer is removed after removing the organic substance.Type: GrantFiled: November 21, 2006Date of Patent: October 28, 2008Assignee: Sumco CorporationInventors: Akihiko Endo, Tatsumi Kusaba
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Publication number: 20080213974Abstract: The present invention provides a method of manufacturing a bonded wafer. The method comprises an oxidation step in which an oxide film is formed on at least one surface of a base wafer, a bonding step in which the base wafer on which the oxide film has been formed is bonded to a top wafer to form a bonded wafer, and a thinning step in which the top wafer included in the bonded wafer is thinned. The oxidation step comprises heating the base wafer to a heating temperature ranging from 800 to 1300° C. at a rate of temperature increase ranging from 1 to 300° C./second in an oxidizing atmosphere, and the bonding step is carried out so as to position the oxide film formed in the oxidation step at an interface of the top wafer and the base wafer.Type: ApplicationFiled: December 17, 2007Publication date: September 4, 2008Applicant: SUMCO CORPORATIONInventors: Hidehiko OKUDA, Tatsumi KUSABA, Akihiko ENDO