Patents by Inventor Kazunari Kurita

Kazunari Kurita 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).

  • Patent number: 7993942
    Abstract: A method of detecting heavy metal in a semiconductor substrate, includes: a gate oxide film forming step of forming an organic oxide film by spin coating or a sol-gel process, and forming a metal/oxide film/semiconductor junction element by using a mercury probe method; and a step of detecting and quantifying heavy metal by calculating the surface concentration of the heavy metal from junction capacitance characteristics of the element.
    Type: Grant
    Filed: April 13, 2009
    Date of Patent: August 9, 2011
    Assignee: Sumco Corporation
    Inventor: Kazunari Kurita
  • Publication number: 20110189805
    Abstract: An object of the present invention is to provide a method of producing a silicon wafer and a method of producing an epitaxial wafer, which enable easily forming a gettering site in a relatively short period of time and effectively suppressing occurrence of dislocation induced by internal stresses. Specifically, the present invention provides a method of producing a silicon wafer, comprising: irradiating a first laser beam having a relatively long wavelength and a second laser beam having a relatively short wavelength onto a portion of a silicon wafer located at a predetermined depth measured from a surface of the silicon wafer, wherein the first laser beam is concentrated at a portion located at a predetermined depth of the wafer to form a process-affected layer for gettering heavy metals thereat, the second laser beam is concentrated at a beam-concentration portion in the vicinity of the surface of the wafer to melt the beam-concentration portion, the beam-concentration portion is then recrystallized.
    Type: Application
    Filed: January 28, 2011
    Publication date: August 4, 2011
    Applicant: SUMCO CORPORATION
    Inventor: Kazunari Kurita
  • Patent number: 7960249
    Abstract: A wafer for backside illumination type solid imaging device having a plurality of pixels inclusive of a photoelectric conversion device and a charge transfer transistor at its front surface side and a light receiving surface at its back surface side is produced by a method comprising a step of forming a BOX oxide layer on at least one of a wafer for support substrate and a wafer for active layer, a step of bonding the wafer for support substrate and the wafer for active layer and a step of thinning the wafer for active layer, which further comprises a step of forming a plurality of concave portions on a bonding face of the BOX oxide layer to the other wafer and filling a polysilicon plug into each of the concave portions to form a composite layer before the step of bonding the wafer for support substrate and the wafer for active layer.
    Type: Grant
    Filed: September 3, 2009
    Date of Patent: June 14, 2011
    Assignee: Sumco Corporation
    Inventors: Kazunari Kurita, Shuichi Omote
  • Patent number: 7919776
    Abstract: A high frequency diode comprising: a P type region, an N type region, and an I layer as a high resistivity layer interposed between the P type region and the N type region, wherein the I layer is made of a silicon wafer that has a carbon concentration of 5×1015 to 5×1017 atoms/cm3, interstitial oxygen concentration of 6.5×1017 to 13.5×1017 atoms/cm3, and a resistivity of 100 ?cm or more.
    Type: Grant
    Filed: January 30, 2007
    Date of Patent: April 5, 2011
    Assignee: Sumco Corporation
    Inventor: Kazunari Kurita
  • Patent number: 7915145
    Abstract: A silicon substrate is manufactured from single-crystal silicon which is grown to have a carbon concentration equal to or higher than 1.0×1016 atoms/cm3 and equal to or lower than 1.6×1017 atoms/cm3 and an initial oxygen concentration equal to or higher than 1.4×1018 atoms/cm3 and equal to or lower than 1.6×1018 atoms/cm3 by a CZ method. A device is formed on a front, the thickness of the silicon substrate is equal to or more than 5 ?m and equal to or less than 40 ?m, and extrinsic gettering which produces residual stress equal to or more than 5 Mpa and equal to or less than 200 Mpa is applied to a back face of the substrate.
    Type: Grant
    Filed: February 24, 2009
    Date of Patent: March 29, 2011
    Assignee: Sumco Corporation
    Inventors: Kazunari Kurita, Shuichi Omote
  • Publication number: 20110049664
    Abstract: Provided is an epitaxial substrate for a back-illuminated image sensor and a manufacturing method thereof that is capable of suppressing metal contaminations and reducing occurrence of a white spot defect of the image sensor, by maintaining a sufficient gettering performance in a device process. The present invention includes forming a gettering sink immediately below a surface of a high-oxygen silicon substrate, forming a first epitaxial layer on the surface of the high-oxygen silicon substrate, and forming a second epitaxial layer on the first epitaxial layer, in which the step of forming the gettering sink includes forming an oxygen precipitate region by applying a long-time heat treatment at a temperature of 650-1150° C. to the high-oxygen silicon substrate.
    Type: Application
    Filed: August 31, 2010
    Publication date: March 3, 2011
    Applicant: SUMCO CORPORATION
    Inventor: Kazunari Kurita
  • Patent number: 7893434
    Abstract: A high frequency diode comprising: a P type region, an N type region, and an I layer as a high resistivity layer interposed between the P type region and the N type region, wherein the I layer is made of a silicon wafer that has a carbon concentration of 5×1015 to 5×1017 atoms/cm3, interstitial oxygen concentration of 6.5×1017 to 13.5×1017 atoms/cm3, and a resistivity of 100 ?cm or more.
    Type: Grant
    Filed: December 3, 2008
    Date of Patent: February 22, 2011
    Assignee: Sumco Corporation
    Inventor: Kazunari Kurita
  • Patent number: 7879695
    Abstract: A method of manufacturing a thin silicon wafer by slicing a silicon single crystal includes: a thinning step S3 of polishing a rear surface of the silicon wafer to reduce the thickness of the silicon wafer after a device structure is formed on a front surface of the silicon wafer; a mirror surface forming step S4 of processing the rear surface of the silicon wafer into a mirror surface using a chemical mechanical polishing method; and a modifying step S5 of dispersing abrasive grains that are harder than those used to form the mirror surface in the mirror surface forming process and forming a damaged layer, serving as a gettering sink for heavy metal, on the rear surface of the silicon wafer using the chemical mechanical polishing method. The thickness T5b of the damaged layer W5b in a wafer depth direction is set by the chemical mechanical polishing method in the modifying step S5 to control the gettering capability of the damaged layer.
    Type: Grant
    Filed: April 13, 2009
    Date of Patent: February 1, 2011
    Assignee: Sumco Corporation
    Inventors: Kazunari Kurita, Shuichi Omote
  • Publication number: 20100311199
    Abstract: A method of producing an epitaxial substrate for a solid-state imaging device, comprising: forming a gettering sink by injecting laser beam to a semiconductor substrate through one surface thereof, condensing the laser beam to an arbitrarily selected portion of the semiconductor substrate, thereby causing multi-photon absorption process to occur in the portion, and forming a gettering sink having a modified crystal structure; and epitaxially growing at least two epitaxial layers on the semiconductor substrate in which the gettering sink is formed.
    Type: Application
    Filed: May 28, 2010
    Publication date: December 9, 2010
    Applicant: SUMCO CORPORATION
    Inventor: Kazunari KURITA
  • Publication number: 20100304552
    Abstract: A method for manufacturing a semiconductor substrate dedicated to a semiconductor device, in which multi-photon absorption is generated in a micro-region inside the semiconductor substrate by condensing laser beams in any micro-region inside the semiconductor substrate, and a gettering sink is formed by changing the crystal structure of only the micro-region.
    Type: Application
    Filed: May 26, 2010
    Publication date: December 2, 2010
    Applicant: SUMCO CORPORATION
    Inventor: Kazunari KURITA
  • Patent number: 7803228
    Abstract: By using oxygen-containing silicon wafers obtained by the CZ method and by combining the first heat treatment comprising controlled heat-up operation (ramping) with the second heat treatment comprising high-temperature heat treatment and medium temperature heat treatment in accordance with the process for producing high-resistance silicon wafers according to the present invention, it is possible to obtain high-resistance silicon wafers capable of maintaining their high resistance even after heat treatment in the process of device manufacture while efficiently inhibiting the formation of oxygen donors and preventing changes in resistivity. Further, excellent epitaxial wafers and SOI wafers can be produced using those high-resistance silicon wafers and, therefore, they can be applied in a wide field including high-frequency communication devices and analog/digital hybrid devices, among others.
    Type: Grant
    Filed: August 2, 2004
    Date of Patent: September 28, 2010
    Assignee: Sumco Corporation
    Inventors: Kazunari Kurita, Shinsuke Sadamitsu, Hiroyuki Takao, Masataka Hourai
  • Publication number: 20100224968
    Abstract: This method for manufacturing a high resistivity silicon wafer includes pulling a single crystal such that the single crystal has a p-type dopant concentration at which a wafer surface resistivity becomes in a range of 0.1 to 10 k?cm, an oxygen concentration Oi of 5.0×1017 to 20×1017 atoms/cm3 (ASTM F-121, 1979), and either one of a nitrogen concentration of 1.0×1013 to 10×1013 atoms/cm3 (ASTM F-121, 1979) and a carbon concentration of 0.5×1016 to 10×1016 atoms/cm3 or 0.5×1016 to 50×1016 atoms/cm3 (ASTM F-123, 1981) by using a Czochralski method, processing the single crystal into wafers by slicing the single crystal, and subjecting the wafer to an oxygen out-diffusion heat treatment process in a non-oxidizing atmosphere.
    Type: Application
    Filed: March 1, 2010
    Publication date: September 9, 2010
    Applicant: SUMCO CORPORATION
    Inventor: Kazunari Kurita
  • Publication number: 20100148297
    Abstract: There is provided a semiconductor substrate for solid-state image sensing device in which the production cost is lower than that of a gettering method through a carbon ion implantation and problems such as occurrence of particles at a device production step and the like are solved. Silicon substrate contains solid-soluted carbon having a concentration of 1×1016-1×1017 atoms/cm3 and solid-soluted oxygen having a concentration of 1.4×1018-1.6×1018 atoms/cm3.
    Type: Application
    Filed: September 7, 2007
    Publication date: June 17, 2010
    Applicant: SUMCO CORPORATION
    Inventor: Kazunari Kurita
  • Publication number: 20100062584
    Abstract: A wafer for backside illumination type solid imaging device having a plurality of pixels inclusive of a photoelectric conversion device and a charge transfer transistor at its front surface side and a light receiving surface at its back surface side is produced by a method comprising a step of forming a BOX oxide layer on at least one of a wafer for support substrate and a wafer for active layer, a step of bonding the wafer for support substrate and the wafer for active layer and a step of thinning the wafer for active layer, which further comprises a step of forming a plurality of concave portions on a bonding face of the BOX oxide layer to the other wafer and filling a polysilicon plug into each of the concave portions to form a composite layer before the step of bonding the wafer for support substrate and the wafer for active layer.
    Type: Application
    Filed: September 3, 2009
    Publication date: March 11, 2010
    Applicant: Sumco Corporation
    Inventors: Kazunari Kurita, Shuichi Omote
  • Publication number: 20100047953
    Abstract: In the production of a wafer for backside illumination type solid imaging device having a plurality of pixels inclusive of a photoelectric conversion device and a charge transfer transistor formed at its front surface side and a light receiving surface at its back surface side, an active layer made of a given epitaxial film is formed on a silicon wafer made of a C-containing CZ crystal directly or through an insulating film, and then subjected to a heat treatment to form precipitates containing C and O as a gettering sink at a position just beneath the active layer.
    Type: Application
    Filed: August 20, 2009
    Publication date: February 25, 2010
    Applicant: SUMCO CORPORATION
    Inventors: Kazunari KURITA, Shuichi OMOTE
  • Publication number: 20100025799
    Abstract: A wafer for backside illumination type solid imaging device has a plurality of pixels inclusive of a photoelectric conversion device and a charge transfer transistor at its front surface side and a light receiving surface at its back surface side, wherein said wafer is a SOI wafer obtained by forming a given active layer on a support substrate made of C-containing n-type semiconductor material through a chemical oxide film having a thickness of not more than 1 nm.
    Type: Application
    Filed: July 30, 2009
    Publication date: February 4, 2010
    Applicant: SUMCO CORPORATION
    Inventor: Kazunari Kurita
  • Publication number: 20090321883
    Abstract: This method for manufacturing a silicon substrate for a solid-state imaging device, includes: a carbon compound layer forming step of forming a carbon compound layer on the surface of a silicon substrate; an epitaxial step of forming a silicon epitaxial layer on the carbon compound layer; and a heat treatment step of subjecting the silicon substrate having the epitaxial layer formed thereon to a heat treatment at a temperature of 600 and 800° C. for 0.25 to 3 hours so as to form gettering sinks that are complexes of carbon and oxygen below the epitaxial layer. This silicon substrate for a solid-state imaging device is manufactured by the above-mentioned method and includes: n epitaxial layer positioned on the surface of a silicon substrate; and a gettering layer which is positioned below the epitaxial layer and includes BMDs having a size of 10 to 100 nm at a concentration of 1.0×106 to 1.0×109 atoms/cm3.
    Type: Application
    Filed: June 25, 2009
    Publication date: December 31, 2009
    Applicant: SUMCO CORPORATION
    Inventor: Kazunari KURITA
  • Publication number: 20090289283
    Abstract: A wafer for backside illumination type solid imaging device has a plurality of pixels inclusive of a photoelectric conversion device and a charge transfer transistor at its front surface side and a light receiving surface at its back surface side, wherein said wafer is a SOI wafer obtained by forming a given active layer on a support substrate made of C-containing p-type semiconductor material through an insulating layer.
    Type: Application
    Filed: May 20, 2009
    Publication date: November 26, 2009
    Applicant: Sumco Corporation
    Inventors: Kazunari Kurita, Shuichi Omote
  • Patent number: 7621996
    Abstract: A method for producing a silicon wafer that has a carbon concentration of 5×1015 to 5×1017 atoms/cm3, interstitial oxygen concentration of 6.5×1017 to 13.5×1017 atoms/cm3, and a resistivity of 100 ?cm or more.
    Type: Grant
    Filed: August 29, 2008
    Date of Patent: November 24, 2009
    Assignee: Sumco Corporation
    Inventor: Kazunari Kurita
  • Publication number: 20090280623
    Abstract: A semiconductor wafer is produced by irradiating a laser beam to either face of a semiconductor wafer so as to fit a focusing position into a given depth position of the semiconductor wafer to generate a multiphoton absorption process only in a specific portion of the semiconductor wafer at the given depth position to thereby form a gettering sink.
    Type: Application
    Filed: May 6, 2009
    Publication date: November 12, 2009
    Applicant: Sumco Corporation
    Inventor: Kazunari KURITA