Patents by Inventor Makoto Ohkawa

Makoto Ohkawa 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: 20070235842
    Abstract: A method for cutting a semiconductor device is provided. The device includes a first semiconductor layer, an insulation layer, and a second semiconductor layer. The method includes the steps of: forming a semiconductor part in the first semiconductor layer; irradiating a laser beam on a surface of the first semiconductor layer; and cutting the device into a semiconductor chip by using the laser beam. The laser beam is reflected at an interface so that a first reflected beam is generated, and the laser beam is reflected at another interface so that a second reflected beam is generated. The insulation film has a thickness, which is determined to weaken the first and second reflected beams each other.
    Type: Application
    Filed: February 15, 2007
    Publication date: October 11, 2007
    Applicant: DENSO CORPORATION
    Inventor: Makoto Ohkawa
  • Patent number: 7199026
    Abstract: A method for cutting a semiconductor device is provided. The device includes a first semiconductor layer, an insulation layer, and a second semiconductor layer. The method includes the steps of: forming a semiconductor part in the first semiconductor layer; irradiating a laser beam on a surface of the first semiconductor layer; and cutting the device into a semiconductor chip by using the laser beam. The laser beam is reflected at an interface so that a first reflected beam is generated, and the laser beam is reflected at another interface so that a second reflected beam is generated. The insulation film has a thickness, which is determined to weaken the first and second reflected beams each other.
    Type: Grant
    Filed: September 30, 2004
    Date of Patent: April 3, 2007
    Assignee: Denso Corporation
    Inventor: Makoto Ohkawa
  • Publication number: 20050082644
    Abstract: A method for cutting a semiconductor device is provided. The device includes a first semiconductor layer, an insulation layer, and a second semiconductor layer. The method includes the steps of: forming a semiconductor part in the first semiconductor layer; irradiating a laser beam on a surface of the first semiconductor layer; and cutting the device into a semiconductor chip by using the laser beam. The laser beam is reflected at an interface so that a first reflected beam is generated, and the laser beam is reflected at another interface so that a second reflected beam is generated. The insulation film has a thickness, which is determined to weaken the first and second reflected beams each other.
    Type: Application
    Filed: September 30, 2004
    Publication date: April 21, 2005
    Inventor: Makoto Ohkawa
  • Patent number: 6809034
    Abstract: An Al film is formed on a barrier metal covering a thin film resistor to have a first opening. A photo-resist is formed on the Al film and in the opening, and is patterned to have a second opening having an opening area smaller than that of the first opening and open in the first opening to expose the barrier metal therefrom. Then, the barrier metal is etched through the second opening. Because the barrier metal is etched from an inner portion more than the opening end of the first opening, under-cut of the barrier metal is prevented.
    Type: Grant
    Filed: April 24, 2002
    Date of Patent: October 26, 2004
    Assignee: Denso Corporation
    Inventors: Ichiro Ito, Satoshi Shiraki, Tomio Yamamoto, Makoto Ohkawa, Atsumi Takahashi, Yasuaki Tsuzuki, Akito Fukui, Toshio Sakakibara, Takayuki Sugisaka
  • Patent number: 6770564
    Abstract: An Al film is formed on a barrier metal covering a thin film resistor to have a first opening. A photo-resist is formed on the Al film and in the opening, and is patterned to have a second opening having an opening area smaller than that of the first opening and open in the first opening to expose the barrier metal therefrom. Then, the barrier metal is etched through the second opening. Because the barrier metal is etched from an inner portion more than the opening end of the first opening, under-cut of the barrier metal is prevented.
    Type: Grant
    Filed: July 28, 1999
    Date of Patent: August 3, 2004
    Assignee: Denso Corporation
    Inventors: Ichiro Ito, Satoshi Shiraki, Tomio Yamamoto, Makoto Ohkawa, Atsumi Takahashi, Yasuaki Tsuzuki, Akito Fukui, Toshio Sakakibara, Takayuki Sugisaka
  • Patent number: 6656755
    Abstract: When an SOI substrate composed of a support wafer and an element formation wafer that are bonded together with an insulating film interposed therebetween is polished from a surface of the element formation wafer, a thickness of the element formation wafer is measured based on a relation between an intensity and a wavelength of a light that is irradiated to the SOI substrate from a side of the support wafer and is reflected by the SOI substrate. Thus, the measurement of the thickness of the element formation wafer can be performed simultaneouly with the polishing of the SOI substrate.
    Type: Grant
    Filed: November 13, 2000
    Date of Patent: December 2, 2003
    Assignee: Denso Corporation
    Inventor: Makoto Ohkawa
  • Patent number: 6645045
    Abstract: The disclosed method of measuring the thickness of an active layer of an SOI substrate maintains the accuracy of previous methods but can be performed quickly and during processing of the substrate. The method includes reading data from light reflected from the substrate. A range of light wavelengths for analysis is selected, which avoids the problem of nodes, at which interference between light reflected from different surfaces is weakened. The method determines a relationship between wavelength and reflection intensity and determines peak values of the relationship. The wavelengths corresponding to an arbitrary pair of the peak values, and the number of waves between the peak values, are used to calculate the thickness of the active layer. The method includes an error correction procedure that increases measurement accuracy.
    Type: Grant
    Filed: March 11, 2002
    Date of Patent: November 11, 2003
    Assignee: Denso Corporation
    Inventor: Makoto Ohkawa
  • Patent number: 6645875
    Abstract: When a barrier metal disposed on a thin film resistor material is wet-etched to expose the underlying thin film resistor material as a thin film resistor, the wet etching is performed at first and second steps. The first step is performed using H2O2/NH4OH solution, and is stopped before the thin film resistor material is exposed. Then, the second step is performed using H2O2/H2O solution until the thin film resistor material is exposed with a desired length, thereby forming the thin film resistor.
    Type: Grant
    Filed: April 4, 2001
    Date of Patent: November 11, 2003
    Assignee: Denso Corporation
    Inventors: Makoto Ohkawa, Takayuki Sugisaka, Shuichi Ito, Hiroshi Tanaka
  • Publication number: 20020173084
    Abstract: The disclosed method of measuring the thickness of an active layer of an SOI substrate maintains the accuracy of previous methods but can be performed quickly and during processing of the substrate. The method includes reading data from light reflected from the substrate. A range of light wavelengths for analysis is selected, which avoids the problem of nodes, at which interference between light reflected from different surfaces is weakened. The method determines a relationship between wavelength and reflection intensity and determines peak values of the relationship. The wavelengths corresponding to an arbitrary pair of the peak values, and the number of waves between the peak values, are used to calculate the thickness of the active layer. The method includes an error correction procedure that increases measurement accuracy.
    Type: Application
    Filed: March 11, 2002
    Publication date: November 21, 2002
    Inventor: Makoto Ohkawa
  • Publication number: 20020115299
    Abstract: An Al film is formed on a barrier metal covering a thin film resistor to have a first opening. A photo-resist is formed on the Al film and in the opening, and is patterned to have a second opening having an opening area smaller than that of the first opening and open in the first opening to expose the barrier metal therefrom. Then, the barrier metal is etched through the second opening. Because the barrier metal is etched from an inner portion more than the opening end of the first opening, under-cut of the barrier metal is prevented.
    Type: Application
    Filed: April 24, 2002
    Publication date: August 22, 2002
    Inventors: Ichiro Ito, Satoshi Shiraki, Tomio Yamamoto, Makoto Ohkawa, Atsumi Takahashi, Yasuaki Tsuzuki, Akito Fukui, Toshio Sakakibara, Takayuki Sugisaka
  • Publication number: 20010029080
    Abstract: When a barrier metal disposed on a thin film resistor material is wet-etched to expose the underlying thin film resistor material as a thin film resistor, the wet etching is performed at first and second steps. The first step is performed using H2O2/NH4OH solution, and is stopped before the thin film resistor material is exposed. Then, the second step is performed using H2O2/H2O solution until the thin film resistor material is exposed with a desired length, thereby forming the thin film resistor.
    Type: Application
    Filed: April 4, 2001
    Publication date: October 11, 2001
    Inventors: Makoto Ohkawa, Takayuki Sugisaka, Shuichi Ito, Hiroshi Tanaka
  • Patent number: 6279585
    Abstract: In a method for manufacturing a semiconductor device, a barrier metal disposed on a metallic thin film for forming a thin film resistor is patterned by wet-etching. The wet-etching produces a residue of the barrier metal. The residue is removed after the oxidation thereof. Accordingly the residue is completely removed. As a result, the patterning of the thin film resistor is stably performed, and short-circuit does not occur to a wiring pattern disposed above the barrier metal.
    Type: Grant
    Filed: September 7, 1999
    Date of Patent: August 28, 2001
    Assignee: Denso Corporation
    Inventors: Satoshi Shiraki, Makoto Ohkawa
  • Patent number: 5989970
    Abstract: Even when a contact hole is formed before thin-film resistor formation, a contact area exposed in the contact hole is prevented from damaging. A semiconductor element is formed in a silicon semiconductor substrate and an oxide film is formed on the surface of the semiconductor substrate. Then, a contact hole is formed on the oxide film and moreover, a CrSiN film serving as a thin-film resistor and a TiW film serving as a barrier metal are formed on the oxide film. The TiW film is patterned by a mask and the CrSiN film is patterned through chemical dry etching. Finally, an Al electrode is formed on the semiconductor element and the CrSiN film through the contact hole and moreover a protective film is formed thereon.
    Type: Grant
    Filed: December 30, 1996
    Date of Patent: November 23, 1999
    Assignee: Nippondenso Co., Ltd.
    Inventors: Makoto Ohkawa, Makio Iida, Mikimasa Suzuki
  • Patent number: 5625218
    Abstract: A fuse fusible type semiconductor device capable of reducing energy required for fusing and a production method of the semiconductor device. In a semiconductor device equipped with a heat-fusible thin film resistor, the thin film resistor formed on a substrate 1 through an insulating film 2 is made of chromium, silicon and tungsten, and films 7 and 8 of a insulator including silicon laminated on the upper surface of the fusing surface, aluminum films 5 are disposed on both sides of the fusing surface and a barrier film 4. This semiconductor device is produced by a lamination step of sequentially forming a first insulating film 2, a thin film resistor 3, a barrier film 4 and an aluminum film 5 on a substrate 1 for reducing drastically fusing energy, an etching step of removing the barrier film 4 and the aluminum film 5 from the fusing region 31 of the thin film resistor 3, and an oxide film formation step of depositing the insulator including silicon films 7 and 8.
    Type: Grant
    Filed: June 16, 1995
    Date of Patent: April 29, 1997
    Assignees: Nippondenso Co., Ltd., Kabushiki Kaisha Toyota Chuo Kenkyusho
    Inventors: Hideya Yamadera, Takeshi Ohwaki, Yasunori Taga, Makio Iida, Makoto Ohkawa, Hirofumi Abe, Yoshihiko Isobe
  • Patent number: 5525831
    Abstract: A thin film resistor on a semiconductor device may be laser trimmed while reducing the influence of film thickness of a passivation film formed on the thin film resistor. An underlying oxide film consisting of a BPSG film and a silicon oxide film is formed on an Si substrate. A silicon oxide film and a silicon nitride film are formed on the underlying film as a passivation film, and a silicon oxide film is formed on this assembly. The silicon oxide film contributes to controlling a variation of the laser energy absorption rate of a thin film resistor due to an uneven thickness of the silicon nitride film. Thus, it is possible to stabilize adjustment of the resistance value of the thin film resistor with a laser.
    Type: Grant
    Filed: April 5, 1994
    Date of Patent: June 11, 1996
    Assignee: Nippondenso Co., Ltd.
    Inventors: Makoto Ohkawa, Makio Iida, Shoji Miura, Osamu Ishihara, Tetsuaki Kamiya
  • Patent number: 4829029
    Abstract: A low temperature sintering ceramic material, having low temperature sinterability and excellent thermal conductivity, is particularly suitable for use in making an IC substrate of a ceramic printed plate board. This low temperature sintering ceramic material has two composition types. One is a binary composition type ceramic material consisting essentially of MgO and B.sub.2 O.sub.3, and the other is a ternary composition type ceramic material composed of principal components consisting of MgO and B.sub.2 O.sub.3 and assisting components consisting of one or more selected from Li.sub.2 O, Na.sub.2 O, K.sub.2 O, a fluoride of an alkali metal and a fluoride of an alkaline earth metal. After sintering, MgO and B.sub.2 O.sub.3 are respectively contained at 50 to 90 mol% and 10 to 50 mol% on 100 mol% of the total amount of MgO and B.sub.2 O.sub.3.
    Type: Grant
    Filed: September 1, 1987
    Date of Patent: May 9, 1989
    Assignee: Nippondenso Co., Ltd.
    Inventors: Nobuaki Kawahara, Hiroki Hoshizaki, Hirofumi Suzuki, Kiyomi Kobayashi, Makoto Ohkawa, Mitsuru Asano