Patents by Inventor Akihiko Endo
Akihiko Endo 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: 7902043Abstract: A method of producing a bonded wafer, comprising: performing bonding of a first semiconductor wafer and a second semiconductor wafer without interposing an insulation film in between; and performing thinning of the second semiconductor wafer, wherein surface portions at least including bonded surfaces of the first semiconductor wafer and the second semiconductor wafer have an oxygen concentration of 1.0×1018 atoms/cm3 (Old ASTM) or less.Type: GrantFiled: September 14, 2007Date of Patent: March 8, 2011Assignee: Sumco CorporationInventors: Nobuyuki Morimoto, Akihiko Endo
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Publication number: 20110027969Abstract: There is provided a method for suppressing the occurrence of defects such as voids or blisters even in the laminated wafer having no oxide film wherein hydrogen ions are implanted into a wafer for active layer having no oxide film on its surface to form a hydrogen ion implanted layer, and ions other than hydrogen are implanted up to a position that a depth from the surface side the hydrogen ion implantation is shallower than the hydrogen ion implanted layer, and the wafer for active layer is laminated onto a wafer for support substrate, and then the wafer for active layer is exfoliated at the hydrogen ion implanted layer.Type: ApplicationFiled: October 12, 2010Publication date: February 3, 2011Applicant: SUMCO CORPORATIONInventors: Satoshi MURAKAMI, Nobuyuki Morimoto, Hideki Nishihata, Akihiko Endo
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Patent number: 7867877Abstract: A method for manufacturing SOI wafers is provided which allows the obtaining of a thin SOI layer having uniform in-plane thickness. In this manufacturing method, an oxygen ion implanted layer is first formed on an active layer wafer. This is then laminated to a base wafer with a embedded oxide film interposed therebetween. The active layer wafer side of the laminated wafer is then ground to remove a portion thereof. The remaining surface side of the active layer wafer is removed by polishing or KOH etching to expose the oxygen ion implanted layer. Oxygen ions are implanted to a uniform depth within the plane of the oxygen ion implanted layer in this oxygen ion implanted layer. Subsequently, oxidizing treatment is carried out to form an oxide film on the exposed surface of the oxygen ion implanted layer. Moreover, this oxide film is removed together with the oxygen ion implanted layer by an HF solution. The remaining portion of the active layer wafer serves as a thin SOI layer.Type: GrantFiled: January 28, 2005Date of Patent: January 11, 2011Assignee: Sumco CorporationInventors: Etsuro Morita, Akihiko Endo
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Patent number: 7858494Abstract: Adhesion of particles due to static buildup during a laminated substrate manufacturing process is constrained, so as to reduce generation of a void or a blister in a lamination step and improve yield. A laminate 13 is formed by superimposing a first semiconductor substrate 11, which is to be an active layer, on a second semiconductor substrate 12, which is to be a supporting substrate, via an oxide film 11a. Electric resistance of either or both of the first and second semiconductor substrates 11 and 12 before superimposition is 0.005-0.2 ?cm.Type: GrantFiled: August 24, 2006Date of Patent: December 28, 2010Assignee: Sumco CorporationInventors: Akihiko Endo, Hideki Nishihata, Nobuyuki Morimoto
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Patent number: 7855132Abstract: The present invention provides a method of manufacturing a bonded wafer. The method includes forming an oxygen ion implantation layer in an active layer wafer having a substrate resistivity of 1 to 100 m?cm by implanting oxygen ions in the active layer wafer, bonding a base wafer and the active layer wafer directly or through an insulating layer to form a bonded wafer, heat treating the bonded wafer to strengthen the bond and convert the oxygen ion implantation layer into a stop layer, grinding, polishing, and/or etching, from the active layer wafer surface side, the bonded wafer in which the bond has been strengthened to expose the stop layer on a surface of the bonded wafer, removing the stop layer, and subjecting the bonded wafer from which the stop layer has been removed to a heat treatment under a reducing atmosphere to diffuse an electrically conductive component comprised in the active layer wafer.Type: GrantFiled: March 28, 2008Date of Patent: December 21, 2010Assignee: Sumco CorporationInventors: Akihiko Endo, Nobuyuki Morimoto
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Patent number: 7851337Abstract: There is provided a method for suppressing the occurrence of defects such as voids or blisters even in the laminated wafer having no oxide film wherein hydrogen ions are implanted into a wafer for active layer having no oxide film on its surface to form a hydrogen ion implanted layer, and ions other than hydrogen are implanted up to a position that a depth from the surface side the hydrogen ion implantation is shallower than the hydrogen ion implanted layer, and the wafer for active layer is laminated onto a wafer for support substrate, and then the wafer for active layer is exfoliated at the hydrogen ion implanted layer.Type: GrantFiled: May 9, 2007Date of Patent: December 14, 2010Assignee: Sumco CorporationInventors: Satoshi Murakami, Nobuyuki Morimoto, Hideki Nishihata, Akihiko Endo
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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: 7795117Abstract: There is provided a method for suppressing the occurrence of defects such as voids or blisters even in the laminated wafer having an oxide film of a thickness thinner than the conventional one, wherein hydrogen ions are implanted into a wafer for active layer having an oxide film of not more than 50 nm in thickness to form a hydrogen ion implanted layer, and ions other than hydrogen are implanted up to a position that a depth from the surface side the hydrogen ion implantation is shallower than the hydrogen ion implanted layer, and the wafer for active layer is laminated onto a wafer for support substrate through the oxide film, and then the wafer for active layer is exfoliated at the hydrogen ion implanted layer.Type: GrantFiled: April 25, 2007Date of Patent: September 14, 2010Assignee: Sumco CorporationInventors: Satoshi Murakami, Nobuyuki Morimoto, Hideki Nishihata, Akihiko Endo
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Patent number: 7790573Abstract: A process for producing an SOI substrate includes the steps of forming an oxide film on at least the front surface of a first silicon substrate, implanting hydrogen ion from the surface of the first silicon substrate and thereby forming an ion implantation area in the inside of the first silicon substrate, laminating a second silicon substrate onto the first silicon substrate via the oxide film and thereby forming a laminated body of the first silicon substrate and the second silicon substrate bonded with each other, and heating the laminated body at a predetermined temperature and thereby separating the first silicon substrate at the ion implantation area and thereby obtaining an SOI substrate wherein a thin film SOI layer is formed on the second silicon substrate via the oxide film.Type: GrantFiled: March 29, 2006Date of Patent: September 7, 2010Assignee: Sumco CorporationInventors: Akihiko Endo, Toshiaki Ono, Wataru Sugimura
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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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Publication number: 20100178750Abstract: A bonded wafer is produced by removing a part or all of native oxide films formed on each surface of both a wafer for active layer and a wafer for support substrate to be bonded; forming a uniform oxide film with a thickness of less than 5 nm on at least one surface of these wafers by a given oxide film forming method; bonding the wafer for active layer to the wafer for support substrate through the uniform oxide film; thinning the wafer for active layer; and subjecting the bonded wafer to a given heat treatment in a non-oxidizing atmosphere to substantially remove the uniform oxide film existing in the bonding interface.Type: ApplicationFiled: July 15, 2009Publication date: July 15, 2010Applicant: SUMCO CORPORATIONInventors: Satoshi Murakami, Akihiko Endo, Nobuyuki Morimoto, Hideki Nishihata
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Patent number: 7736998Abstract: This SOI substrate includes a base substrate which includes a single-crystal semiconductor and an active layer which includes a single-crystal semiconductor and is bonded to the base substrate with an oxide film therebetween. The oxide film is formed only in the active layer. The active layer is formed with a thickness of 10 to 200 nm and a thickness variation throughout the active layer of 1.5 nm or less by etching a surface of the active layer while selectively using only the reactive radicals generated by a plasma etching process.Type: GrantFiled: May 25, 2005Date of Patent: June 15, 2010Assignee: Sumco CorporationInventors: Etsurou Morita, Ritarou Sano, Akihiko Endo
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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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Patent number: 7713838Abstract: Since a supporting wafer contains boron of 9×1018 atoms/cm3 or more, therefore a part of the metal impurities in an active layer wafer and the metal impurities in the wafer can be captured by the boron during the heat treatment for bonding. As a result, metal contamination in the active layer can be reduced. Moreover, the wafer strength is enhanced, thus preventing the wafer slipping. Since the wafer has no COP, micro voids are not detected in the LPD evaluation of the active layer, thereby improving the reliability of the evaluation. Such a bonded wafer can be manufactured at a low cast.Type: GrantFiled: September 8, 2004Date of Patent: May 11, 2010Assignee: Sumco CorporationInventors: Akihiko Endo, Nobuyuki Morimoto
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Patent number: 7713842Abstract: In a method for producing a bonded wafer by bonding a wafer for active layer to wafer for support layer and then thinning the wafer for active layer, a terrace grinding for forming a terrace portion is carried out prior to a step of exposing the oxygen ion implanted layer to thereby leave an oxide film on a terrace portion of the wafer for support layer.Type: GrantFiled: September 29, 2008Date of Patent: May 11, 2010Assignee: Sumco CorporationInventors: Hideki Nishihata, Isoroku Ono, Akihiko Endo
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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: 20100015779Abstract: There is provided a bonded wafer having excellent thickness uniformity after thinning but also good surface roughness and being less in defects. In the production method of a bonded wafer by bonding a wafer for active layer to a wafer for support substrate and thinning the wafer for active layer, oxygen ions are implanted into the wafer for active layer to form an oxygen ion implanted layer in the active layer and thereafter a heat treatment is carried out in a non-oxidizing atmosphere at a temperature of not lower than 1100° C., and an oxide film formed on the exposed surface of the oxygen ion implanted layer is removed and then a heat treatment is carried out in a non-oxidizing atmosphere at a temperature of not higher than 1100° C.Type: ApplicationFiled: July 4, 2007Publication date: January 21, 2010Applicant: Sumco CorporationInventors: Nobuyuki Morimoto, Akihiko Endo, Etsurou Morita