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).
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Publication number: 20070235842Abstract: 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: ApplicationFiled: February 15, 2007Publication date: October 11, 2007Applicant: DENSO CORPORATIONInventor: Makoto Ohkawa
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Patent number: 7199026Abstract: 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: GrantFiled: September 30, 2004Date of Patent: April 3, 2007Assignee: Denso CorporationInventor: Makoto Ohkawa
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Publication number: 20050082644Abstract: 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: ApplicationFiled: September 30, 2004Publication date: April 21, 2005Inventor: Makoto Ohkawa
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Patent number: 6809034Abstract: 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: GrantFiled: April 24, 2002Date of Patent: October 26, 2004Assignee: Denso CorporationInventors: Ichiro Ito, Satoshi Shiraki, Tomio Yamamoto, Makoto Ohkawa, Atsumi Takahashi, Yasuaki Tsuzuki, Akito Fukui, Toshio Sakakibara, Takayuki Sugisaka
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Patent number: 6770564Abstract: 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: GrantFiled: July 28, 1999Date of Patent: August 3, 2004Assignee: Denso CorporationInventors: Ichiro Ito, Satoshi Shiraki, Tomio Yamamoto, Makoto Ohkawa, Atsumi Takahashi, Yasuaki Tsuzuki, Akito Fukui, Toshio Sakakibara, Takayuki Sugisaka
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Patent number: 6656755Abstract: 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: GrantFiled: November 13, 2000Date of Patent: December 2, 2003Assignee: Denso CorporationInventor: Makoto Ohkawa
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Patent number: 6645875Abstract: 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: GrantFiled: April 4, 2001Date of Patent: November 11, 2003Assignee: Denso CorporationInventors: Makoto Ohkawa, Takayuki Sugisaka, Shuichi Ito, Hiroshi Tanaka
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Patent number: 6645045Abstract: 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: GrantFiled: March 11, 2002Date of Patent: November 11, 2003Assignee: Denso CorporationInventor: Makoto Ohkawa
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Publication number: 20020173084Abstract: 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: ApplicationFiled: March 11, 2002Publication date: November 21, 2002Inventor: Makoto Ohkawa
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Publication number: 20020115299Abstract: 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: ApplicationFiled: April 24, 2002Publication date: August 22, 2002Inventors: Ichiro Ito, Satoshi Shiraki, Tomio Yamamoto, Makoto Ohkawa, Atsumi Takahashi, Yasuaki Tsuzuki, Akito Fukui, Toshio Sakakibara, Takayuki Sugisaka
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Publication number: 20010029080Abstract: 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: ApplicationFiled: April 4, 2001Publication date: October 11, 2001Inventors: Makoto Ohkawa, Takayuki Sugisaka, Shuichi Ito, Hiroshi Tanaka
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Patent number: 6279585Abstract: 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: GrantFiled: September 7, 1999Date of Patent: August 28, 2001Assignee: Denso CorporationInventors: Satoshi Shiraki, Makoto Ohkawa
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Patent number: 5989970Abstract: 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: GrantFiled: December 30, 1996Date of Patent: November 23, 1999Assignee: Nippondenso Co., Ltd.Inventors: Makoto Ohkawa, Makio Iida, Mikimasa Suzuki
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Patent number: 5625218Abstract: 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: GrantFiled: June 16, 1995Date of Patent: April 29, 1997Assignees: Nippondenso Co., Ltd., Kabushiki Kaisha Toyota Chuo KenkyushoInventors: Hideya Yamadera, Takeshi Ohwaki, Yasunori Taga, Makio Iida, Makoto Ohkawa, Hirofumi Abe, Yoshihiko Isobe
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Patent number: 5525831Abstract: 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: GrantFiled: April 5, 1994Date of Patent: June 11, 1996Assignee: Nippondenso Co., Ltd.Inventors: Makoto Ohkawa, Makio Iida, Shoji Miura, Osamu Ishihara, Tetsuaki Kamiya
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Patent number: 4829029Abstract: 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: GrantFiled: September 1, 1987Date of Patent: May 9, 1989Assignee: Nippondenso Co., Ltd.Inventors: Nobuaki Kawahara, Hiroki Hoshizaki, Hirofumi Suzuki, Kiyomi Kobayashi, Makoto Ohkawa, Mitsuru Asano