Patents by Inventor Isao Yokokawa

Isao Yokokawa 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).

  • Publication number: 20190295883
    Abstract: A method for manufacturing an SOI wafer, including steps of: bonding a bond wafer and a base wafer each composed of a silicon wafer at room temperature with a silicon oxide film interposed therebetween; a thinning the bond wafer; and before the bonding step, cleaning the wafers with a hydrophilic cleaning liquid and drying the cleaned wafers by suction drying or spin drying. After the drying step is ended and before the bonding step is started, the wafers are stored until a state where a bonding speed at which the bonding step is to be performed is 20 mm/second or less. The bonding is performed with the bonding speed of 20 mm/second or less. This provides a method for manufacturing an SOI wafer by which an SOI wafer can be manufactured while generation of outer-peripheral micro voids is suppressed in a simple manner.
    Type: Application
    Filed: November 27, 2017
    Publication date: September 26, 2019
    Applicant: SHIN-ETSU HANDOTAI CO., LTD.
    Inventor: Isao YOKOKAWA
  • Patent number: 10347525
    Abstract: A method for producing a bonded SOI wafer, by ion implantation delamination to fabricate a bonded SOI wafer having a BOX layer and a SOI layer on a base wafer. After performing flattening heat treatment in an argon gas-containing atmosphere, sacrificial oxidation treatment adjusts the film thickness of the SOI layer, wherein the film thickness of the BOX layer is 500 nm or more. A sacrificial oxide film is formed so the relationship between the film thickness of the SOI layer on the sacrificial oxidation treatment is performed. The film thickness of the sacrificial oxide film formed by the sacrificial oxidation treatment satisfies 0.9d>t>0.45d. A method for producing a bonded SOI wafer can prevent the generation of particles from the outermost peripheral part, which is the form of an overhang by flattening heat treatment, of a SOI layer in the production of a bonded SOI wafer.
    Type: Grant
    Filed: August 29, 2016
    Date of Patent: July 9, 2019
    Assignee: SHIN-ETSU HANDOTAI CO., LTD.
    Inventor: Isao Yokokawa
  • Publication number: 20190074213
    Abstract: A method for producing a bonded SOI wafer, by ion implantation delamination to fabricate a bonded SOI wafer having a BOX layer and a SOI layer on a base wafer. After performing flattening heat treatment in an argon gas-containing atmosphere, sacrificial oxidation treatment adjusts the film thickness of the SOI layer, wherein the film thickness of the BOX layer is 500 nm or more. A sacrificial oxide film is formed so the relationship between the film thickness of the SOI layer on the sacrificial oxidation treatment is performed. The film thickness of the sacrificial oxide film formed by the sacrificial oxidation treatment satisfies 0.9d>t>0.45d. A method for producing a bonded SOI wafer can prevent the generation of particles from the outermost peripheral part, which is the form of an overhang by flattening heat treatment, of a SOI layer in the production of a bonded SOI wafer.
    Type: Application
    Filed: August 29, 2016
    Publication date: March 7, 2019
    Applicant: SHIN-ETSU HANDOTAI CO., LTD.
    Inventor: Isao YOKOKAWA
  • Patent number: 10204824
    Abstract: A method for producing a SOI wafer that includes implanting at least one type of gas ion selected from a hydrogen ion and a rare gas ion from a surface of a bond wafer formed of a silicon single crystal to form an ion implanted layer, bonding the ion-implanted surface of the bond wafer to a surface of a base wafer formed of a silicon single crystal through a silicon oxide film formed on the base wafer surface, delaminating the bond wafer at the ion implanted layer by performing delamination heat treatment to fabricate a SOI wafer having a buried oxide film layer and a SOI layer on the base wafer, and performing flattening heat treatment on the SOI wafer in an atmosphere containing argon gas.
    Type: Grant
    Filed: March 8, 2016
    Date of Patent: February 12, 2019
    Assignee: SHIN-ETSU HANDOTAI CO., LTD.
    Inventors: Isao Yokokawa, Hiroji Aga, Norihiro Kobayashi
  • Publication number: 20180144975
    Abstract: A method for producing a SOI wafer that includes implanting at least one type of gas ion selected from a hydrogen ion and a rare gas ion from a surface of a bond wafer formed of a silicon single crystal to form an ion implanted layer, bonding the ion-implanted surface of the bond wafer to a surface of a base wafer formed of a silicon single crystal through a silicon oxide film formed on the base wafer surface, delaminating the bond wafer at the ion implanted layer by performing delamination heat treatment to fabricate a SOI wafer having a buried oxide film layer and a SOI layer on the base wafer, and performing flattening heat treatment on the SOI wafer in an atmosphere containing argon gas.
    Type: Application
    Filed: March 8, 2016
    Publication date: May 24, 2018
    Applicant: SHIN-ETSU HANDOTAI CO., LTD.
    Inventors: Isao YOKOKAWA, Hiroji AGA, Norihiro KOBAYASHI
  • Patent number: 9865497
    Abstract: A method for manufacturing bonded wafer including: producing bonded wafer having thin-film on its base wafer by an ion implantation delamination method, and reducing film thickness of the thin-film, wherein the step of reducing the film thickness includes a stage of reducing the film thickness by sacrificial oxidation treatment or vapor phase etching, wherein the method for manufacturing bonded wafer further includes a cleaning step of cleaning the bonded wafer exposing the delamination surface just before the step of reducing the film thickness, wherein the cleaning step includes a stage of performing a wet cleaning by successively dipping the bonded wafer to plural of cleaning baths, and wherein the wet cleaning is performed without applying ultrasonic in each of the cleaning baths in the wet cleaning. The method enables to clean bonded wafer exposing delamination surface remaining damage of ion implantation using a cleaning line in a strict control level.
    Type: Grant
    Filed: August 22, 2014
    Date of Patent: January 9, 2018
    Assignee: SHIN-ETSU HANDOTAI CO., LTD.
    Inventors: Isao Yokokawa, Hiroji Aga, Hiroshi Fujisawa
  • Patent number: 9673086
    Abstract: A method of producing a bonded wafer in which wafers each having a cutout portion are used as a bond wafer and a base wafer, and either or both of settings of an ion implanter with which ions are implanted and conditions of the ion implantation are adjusted in the step of implanting the ions such that a cutout portion of either or both of the bond wafer and the base wafer after bonding is located at within a range of 0±30° or 180±30° from a position at which separation of the bond wafer begins in the step of separating the bond wafer. This method can inhibit the occurrence of large fault defect that may be generated on a surface of a thin film right after the separation, when a thin film such as an SOI layer is formed by the ion implantation separation method.
    Type: Grant
    Filed: July 15, 2014
    Date of Patent: June 6, 2017
    Assignee: SHIN-ETSU HANDOTAI CO., LTD.
    Inventors: Isao Yokokawa, Masahiro Kato
  • Publication number: 20160197008
    Abstract: A method for manufacturing bonded wafer including: producing bonded wafer having thin-film on its base wafer by an ion implantation delamination method, and reducing film thickness of the thin-film, wherein the step of reducing the film thickness includes a stage of reducing the film thickness by sacrificial oxidation treatment or vapor phase etching, wherein the method for manufacturing bonded wafer further includes a cleaning step of cleaning the bonded wafer exposing the delamination surface just before the step of reducing the film thickness, wherein the cleaning step includes a stage of performing a wet cleaning by successively dipping the bonded wafer to plural of cleaning baths, and wherein the wet cleaning is performed without applying ultrasonic in each of the cleaning baths in the wet cleaning. The method enables to clean bonded wafer exposing delamination surface remaining damage of ion implantation using a cleaning line in a strict control level.
    Type: Application
    Filed: August 22, 2014
    Publication date: July 7, 2016
    Applicant: SHIN-ETSU HANDOTAI CO., LTD.
    Inventors: Isao YOKOKAWA, Hiroji AGA, Hiroshi FUJISAWA
  • Publication number: 20160197007
    Abstract: A method of producing a bonded wafer in which wafers each having a cutout portion are used as a bond wafer and a base wafer, and either or both of settings of an ion implanter with which ions are implanted and conditions of the ion implantation are adjusted in the step of implanting the ions such that a cutout portion of either or both of the bond wafer and the base wafer after bonding is located at within a range of 0±30° or 180±30° from a position at which separation of the bond wafer begins in the step of separating the bond wafer. This method can inhibit the occurrence of large fault defect that may be generated on a surface of a thin film right after the separation, when a thin film such as an SOI layer is formed by the ion implantation separation method.
    Type: Application
    Filed: July 15, 2014
    Publication date: July 7, 2016
    Applicant: SHIN-ETSU HANDOTAI CO., LTD.
    Inventors: Isao YOKOKAWA, Masahiro KATO
  • Patent number: 9337080
    Abstract: The present invention is a method for manufacturing an SOI wafer, including: implanting one or more gas ion selected from a hydrogen ion and a rare gas ion into a bond wafer composed of a semiconductor single crystal substrate from a surface of the bond wafer to form an ion-implanted layer; bonding the surface from which the ion is implanted into the bond wafer and a surface of a base wafer through an oxide film; and then delaminating the bond wafer at the ion-implanted layer by performing a delamination heat treatment with a heat treatment furnace to form the SOI wafer, wherein after the delamination heat treatment, a temperature of the heat treatment furnace is decreased to 250° C. or less at temperature-decreasing rate of less than 3.0° C/min, and then the SOI wafer and the bond wafer after delamination are taken out from the heat treatment furnace.
    Type: Grant
    Filed: November 7, 2013
    Date of Patent: May 10, 2016
    Assignee: SHIN-ETSU HANDOTAI CO., LTD.
    Inventors: Hiroji Aga, Isao Yokokawa, Toru Ishizuka
  • Publication number: 20150340279
    Abstract: The present invention provides a method for manufacturing SOI wafer, wherein, after plasma treatment has been performed on at least one surface of a bonding interface of the bond wafer and a bonding interface of the base wafer, bonding is performed through the oxide film, and the bond wafer is delaminated at the ion implanted layer by the delamination heat treatment comprising a first heat treatment at 250° C. or less for 2 hours or more and a second heat treatment at 400° C. to 450° C. for 30 minutes or more. Thereby, the method of manufacturing the SOI wafer that is small in SOI layer film thickness range, is small in surface roughness of the SOI layer surface, is smooth in shape of a terrace part and has no defects such as voids, blisters and so forth in the SOI layer can be provided.
    Type: Application
    Filed: December 10, 2013
    Publication date: November 26, 2015
    Applicant: Shin-Etsu Handotai Co., Ltd.
    Inventors: Norihiro KOBAYASHI, Isao YOKOKAWA, Hiroji AGA
  • Publication number: 20150249035
    Abstract: The present invention is a method for manufacturing an SOI wafer, including: implanting one or more gas ion selected from a hydrogen ion and a rare gas ion into a bond wafer composed of a semiconductor single crystal substrate from a surface of the bond wafer to form an ion-implanted layer; bonding the surface from which the ion is implanted into the bond wafer and a surface of a base wafer through an oxide film; and then delaminating the bond wafer at the ion-implanted layer by performing a delamination heat treatment with a heat treatment furnace to form the SOI wafer, wherein after the delamination heat treatment, a temperature of the heat treatment furnace is decreased to 250° C. or less at temperature-decreasing rate of less than 3.0° C./min, and then the SOI wafer and the bond wafer after delamination are taken out from the heat treatment furnace.
    Type: Application
    Filed: November 7, 2013
    Publication date: September 3, 2015
    Applicant: Shin-Etsu Handotai Co., Ltd.
    Inventors: Hiroji Aga, Isao Yokokawa, Toru Ishizuka
  • Patent number: 9076840
    Abstract: According to the present invention, there is provided a method for manufacturing an SOI wafer having the step of performing a first sacrificial oxidation treatment on the aforementioned bonded SOI wafer in which the delamination has been performed after a first RTA treatment has been performed thereon and then performing a second sacrificial oxidation treatment thereon after a second RTA treatment has been performed thereon, wherein the first and second RTA treatments are performed under a hydrogen gas containing atmosphere and at a temperature of 1100° C. or more, wherein after a thermal oxide film has been formed on the aforementioned SOI layer front surface by performing only thermal oxidation by a batch type heat treating furnace at a temperature of 900° C. or more and 1000° C. or less in the first and second sacrificial oxidation treatments, a treatment for removing the thermal oxide film is performed.
    Type: Grant
    Filed: November 30, 2012
    Date of Patent: July 7, 2015
    Assignee: SHIN-ETSU HANDOTAI CO., LTD.
    Inventors: Norihiro Kobayashi, Hiroji Aga, Isao Yokokawa, Toru Ishizuka, Masahiro Kato
  • Patent number: 8987109
    Abstract: A method for manufacturing a bonded wafer includes: an ion implantation step of using a batch type ion implanter; a bonding step of bonding an ion implanted surface of a bond wafer to a surface of a base wafer directly or through an insulator film; and a delamination step of delaminating the bond wafer at an ion implanted layer, thereby manufacturing a bonded wafer having a thin film on the base wafer, wherein the ion implantation into the bond wafer carried out at the ion implantation step is divided into a plurality of processes, the bond wafer is rotated on its own axis a predetermined rotation angle after each ion implantation, and the next ion implantation is carried out at an arrangement position obtained by the rotation.
    Type: Grant
    Filed: April 25, 2012
    Date of Patent: March 24, 2015
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Hiroji Aga, Isao Yokokawa, Nobuhiko Noto
  • Patent number: 8962352
    Abstract: A method for calculating a warpage of a bonded SOI wafer includes: assuming that the epitaxial growth SOI wafer is a silicon single crystal wafer having the same dopant concentration as dopant concentration of the bond wafer; calculating a warpage A that occurs at the time of performing the epitaxial growth relative to the assumed silicon single crystal wafer; calculating a warpage B caused due to a thickness of the BOX layer of the epitaxial growth SOI wafer; determining a measured value of a warpage of the base wafer before bonding as a warpage C; and calculating a sum of the warpages (A+B+C) as the warpage of the bonded SOI wafer.
    Type: Grant
    Filed: August 21, 2012
    Date of Patent: February 24, 2015
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Isao Yokokawa, Hiroji Aga, Yasushi Mizusawa
  • Patent number: 8956951
    Abstract: A method for manufacturing an SOI wafer includes performing a flattening heat treatment on an SOI wafer under an atmosphere containing an argon gas, in which conditions of SOI wafer preparation are set so that a thickness of an SOI layer of the SOI wafer to be subjected to the flattening heat treatment is 1.4 or more times thicker than that of a BOX layer, and the thickness of the SOI layer is reduced to less than a thickness 1.4 times the thickness of the BOX layer by performing a sacrificial oxidation treatment on the SOI layer of the SOI wafer after the flattening heat treatment.
    Type: Grant
    Filed: September 1, 2010
    Date of Patent: February 17, 2015
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Isao Yokokawa, Masahiro Kato, Masayuki Imai
  • Patent number: 8906708
    Abstract: A method for checking an ion implantation condition when ions are implanted over an entirety of one surface of a semiconductor wafer having an insulator film on the one surface, the method including checking whether the ions are implanted over the entirety of the one surface of the semiconductor wafer by directly or indirectly observing light emitted when the one surface of the semiconductor wafer is irradiated with an ion beam of the implanted ions throughout the ion implantation.
    Type: Grant
    Filed: March 28, 2011
    Date of Patent: December 9, 2014
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventor: Isao Yokokawa
  • Publication number: 20140322895
    Abstract: According to the present invention, there is provided a method for manufacturing an SOI wafer having the step of performing a first sacrificial oxidation treatment on the aforementioned bonded SOI wafer in which the delamination has been performed after a first RTA treatment has been performed thereon and then performing a second sacrificial oxidation treatment thereon after a second RTA treatment has been performed thereon, wherein the first and second RTA treatments are performed under a hydrogen gas containing atmosphere and at a temperature of 1100° C. or more, wherein after a thermal oxide film has been formed on the aforementioned SOI layer front surface by performing only thermal oxidation by a batch type heat treating furnace at a temperature of 900° C. or more and 1000° C. or less in the first and second sacrificial oxidation treatments, a treatment for removing the thermal oxide film is performed.
    Type: Application
    Filed: November 30, 2012
    Publication date: October 30, 2014
    Applicant: SHIN-ETSU HANDOTAI CO., LTD.
    Inventors: Norihiro Kobayashi, Hiroji Aga, Isao Yokokawa, Toru Ishizuka, Masahiro Kato
  • Publication number: 20140186977
    Abstract: A method for calculating a warpage of a bonded SOI wafer includes: assuming that the epitaxial growth SOI wafer is a silicon single crystal wafer having the same dopant concentration as dopant concentration of the bond wafer; calculating a warpage A that occurs at the time of performing the epitaxial growth relative to the assumed silicon single crystal wafer; calculating a warpage B caused due to a thickness of the BOX layer of the epitaxial growth SOI wafer; determining a measured value of a warpage of the base wafer before bonding as a warpage C; and calculating a sum of the warpages (A+B+C) as the warpage of the bonded SOI wafer.
    Type: Application
    Filed: August 21, 2012
    Publication date: July 3, 2014
    Applicant: SHIN-ETSU HANDOTAI CO., LTD.
    Inventors: Isao Yokokawa, Hiroji Aga, Yasushi Mizusawa
  • Patent number: 8728912
    Abstract: The present invention is directed to a method for manufacturing an SOI wafer, the method by which treatment that removes the outer periphery of a buried oxide film to obtain a structure in which a peripheral end of an SOI layer of an SOI wafer is located outside a peripheral end of the buried oxide film, and, after heat treatment is performed on the SOI wafer in a reducing atmosphere containing hydrogen or an atmosphere containing hydrogen chloride gas, an epitaxial layer is formed on a surface of the SOI layer. As a result, there is provided a method that can manufacture an SOI wafer having a desired SOI layer thickness by performing epitaxial growth without allowing a valley-shaped step to be generated in an SOI wafer with no silicon oxide film in a terrace portion, the SOI wafer fabricated by an ion implantation delamination method.
    Type: Grant
    Filed: November 18, 2011
    Date of Patent: May 20, 2014
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Hiroji Aga, Isao Yokokawa, Satoshi Oka