Patents by Inventor Toshifumi Yokoyama

Toshifumi Yokoyama 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: 6764792
    Abstract: The invention relates to a halftone phase shift photomask which is controlled with precision in terms of its transmittance at a wavelength applied to inspection, and measuring equipment, so that its quality can easily be assured even when its phase difference at an exposure wavelength is controlled at 180° C. with precision and its transmittance is set at 1 to 20% as desired at that wavelength. The halftone phase shift photomask (107) comprises on a transparent substrate (101) and a halftone phase shift film containing at least tantalum, oxygen, carbon and nitrogen, and has a multilayer structure comprising at least two or more different layers (102) and (103).
    Type: Grant
    Filed: April 27, 2001
    Date of Patent: July 20, 2004
    Assignee: Dai Nippon Printing Co., Ltd.
    Inventors: Junji Fujikawa, Yoshinori Kinase, Takafumi Okamura, Hiroshi Mohri, Toshifumi Yokoyama, Haruo Kokubo
  • Patent number: 6740455
    Abstract: A photomask is produced which enables the simplification of the steps of lithography. A photomask is provided with shielding patterns made of shielding metallic thin film on a transparent substrate, wherein the photomask further comprises translucent patterns mainly including tantalum of materials selected from tantalum silicide, tantalum oxide, tantalum nitride or mixture thereof.
    Type: Grant
    Filed: December 21, 2001
    Date of Patent: May 25, 2004
    Assignee: Dainippon Printing Co., Ltd.
    Inventors: Kenji Noguchi, Toshiaki Motonaga, Hiro-o Nakagawa, Yasutaka Morikawa, Toshifumi Yokoyama, Takashi Tominaga, Yoshinori Kinase, Junji Fujikawa, Yoichi Takahashi
  • Publication number: 20040032884
    Abstract: A method for easily and quickly evaluating the wavelength variability properties of a wavelength-variable semiconductor laser is provided. An inspection device includes a power source for supplying current to a wavelength-variable DBR semiconductor laser having an active region, a phase control region, and a DBR region, a photo-detector for detecting an output intensity of laser beam emitted from the wavelength-variable DBR semiconductor laser, and a transmission type wavelength-selection element that can be inserted into a light path from the wavelength-variable DBR semiconductor laser to the photo-detector.
    Type: Application
    Filed: August 16, 2002
    Publication date: February 19, 2004
    Applicant: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yasuo Kitaoka, Toshifumi Yokoyama, Kazuhisa Yamamoto
  • Publication number: 20030186135
    Abstract: Disclosed is a blank for a halftone phase shift photomask comprising a transparent substrate and a halftone phase shift layer formed thereon, the halftone phase shift layer being provided with a layer containing molybdenum silicide as its major component and either one or both of oxygen and nitrogen and being formed of a multilayer film with two or more layers, wherein the multilayer film contains a layer whose major component is either one of chromium and tantalum or a chromium tantalum alloy and the layer whose major component is either one of chromium and tantalum or a chromium tantalum alloy is laminated on the side closer to the transparent substrate than the layer containing molybdenum silicide as its major component and either one or both of oxygen and nitrogen.
    Type: Application
    Filed: March 4, 2003
    Publication date: October 2, 2003
    Inventors: Hiro-o Nakagawa, Toshiaki Motonaga, Yoshinori Kinase, Satoshi Yusa, Shigeki Sumida, Toshifumi Yokoyama, Chiaki Hatsuta, Junji Fujikawa, Masashi Ohtsuki
  • Patent number: 6621962
    Abstract: A semiconductor laser and an optical waveguide device with an optical waveguide formed at a surface of its substrate are provided on a submount. The semiconductor laser and the optical waveguide device are mounted with an active layer and a surface at which the optical waveguide is formed facing the submount, respectively. The submount is combined with the semiconductor laser or the optical waveguide device to form one body using an adhesive with a spacer, which maintains a substantially uniform distance therebetween, being interposed therebetween, so that position adjustment in the height direction can be made automatically and mounting can be carried out with high-precision optical coupling. Thus, an optical waveguide device integrated module and a method of manufacturing the same are provided, in which a semiconductor laser and a planar optical waveguide device are mounted with their positions in the height direction controlled with high precision.
    Type: Grant
    Filed: December 16, 2002
    Date of Patent: September 16, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yasuo Kitaoka, Toshifumi Yokoyama, Kazuhisa Yamamoto
  • Patent number: 6614966
    Abstract: A semiconductor laser and an optical waveguide device with an optical waveguide formed at a surface of its substrate are provided on a submount. The semiconductor laser and the optical waveguide device are mounted with an active layer and a surface at which the optical waveguide is formed facing the submount, respectively. The submount is combined with the semiconductor laser or the optical waveguide device to form one body using an adhesive with a spacer, which maintains a substantially uniform distance therebetween, being interposed therebetween, so that position adjustment in the height direction can be made automatically and mounting can be carried out with high-precision optical coupling. Thus, an optical waveguide device integrated module and a method of manufacturing the same are provided, in which a semiconductor laser and a planar optical waveguide device are mounted with their positions in the height direction controlled with high precision.
    Type: Grant
    Filed: March 7, 2001
    Date of Patent: September 2, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yasuo Kitaoka, Toshifumi Yokoyama, Kazuhisa Yamamoto
  • Patent number: 6599667
    Abstract: A blank for halftone phase shift photomask is disclosed. The blank has a transparent substrate, a halftone phase shift layer and a light shielding film, the halftone phase shift layer and the light shielding film being layered in this order on the transparent substrate, and the l light shielding film is a single layered or multiple layered film which has a layer of tantalum.
    Type: Grant
    Filed: April 26, 2001
    Date of Patent: July 29, 2003
    Assignee: Dai Nippon Printing Co., Ltd.
    Inventors: Satoshi Yusa, Toshifumi Yokoyama, Shigeki Sumida, Toshiaki Motonaga, Yoshinori Kinase, Hiro-o Nakagawa, Chiaki Hatsuta, Junji Fujikawa, Masashi Ohtsuki
  • Publication number: 20030133680
    Abstract: The invention provides a method for manufacturing an optical waveguide device, with which the thickness of an optical substrate can be controlled with high precision. The surface of a substrate is masked by applying a resist to all regions of the substrate except where stopper portions are to be formed (i.e. to the left and right in width direction of the substrate). Then, the stopper portions are formed on the surface of the substrate by sputtering/vapor deposition of Cr, and then the resist is removed. Using a UV curing resin, an Mg-doped LiNbO3 optical substrate is laminated between the pair of stopper portions to the left and right of the surface of the substrate. After laminating the optical substrate, which is made of a non-linear optical material, the optical substrate is abraded.
    Type: Application
    Filed: January 2, 2003
    Publication date: July 17, 2003
    Applicant: Matsushita Electric Industrial Co., Ltd.
    Inventors: Toshifumi Yokoyama, Kiminori Mizuuchi
  • Publication number: 20030118292
    Abstract: A semiconductor laser and an optical waveguide device with an optical waveguide formed at a surface of its substrate are provided on a submount. The semiconductor laser and the optical waveguide device are mounted with an active layer and a surface at which the optical waveguide is formed facing the submount, respectively. The submount is combined with the semiconductor laser or the optical waveguide device to form one body using an adhesive with a spacer, which maintains a substantially uniform distance therebetween, being interposed therebetween, so that position adjustment in the height direction can be made automatically and mounting can be carried out with high-precision optical coupling. Thus, an optical waveguide device integrated module and a method of manufacturing the same are provided, in which a semiconductor laser and a planar optical waveguide device are mounted with their positions in the height direction controlled with high precision.
    Type: Application
    Filed: December 16, 2002
    Publication date: June 26, 2003
    Applicant: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yasuo Kitaoka, Toshifumi Yokoyama, Kazuhisa Yamamoto
  • Patent number: 6519077
    Abstract: An optical waveguide of the present invention includes: a nonlinear optical crystal; a first ion exchange region provided in the vicinity of a portion of a surface of the nonlinear optical crystal; and a second ion exchange region provided in the surface of the nonlinear optical crystal. The second ion exchange region covers a greater area of the surface than an area covered by the first ion exchange region. The second ion exchange region includes a region having an extent of 0.02 &mgr;m to 0.2 &mgr;m along a depth direction in which an ion exchange ratio varies along the depth direction.
    Type: Grant
    Filed: March 23, 2000
    Date of Patent: February 11, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kiminori Mizuuchi, Kazuhisa Yamamoto, Yasuo Kitaoka, Toshifumi Yokoyama
  • Patent number: 6458496
    Abstract: A blank for a halftone phase shift photomask in the present invention comprises a transparent substrate and a halftone phase shift film provided thereon, and said halftone phase shift film has a multilayer construction in which at least a first layer capable of being etched with a chlorinated gas and a second layer capable of being etched with a fluorinated gas are disposed in this order from the side near said transparent substrate. A film made of tantalum silicides is suitable to use as the second layer of the halftone phase shift film.
    Type: Grant
    Filed: December 14, 2000
    Date of Patent: October 1, 2002
    Assignee: Dai Nippon Printing Co., Ltd.
    Inventors: Toshiaki Motonaga, Toshifumi Yokoyama, Takafumi Okamura, Yoshinori Kinase, Hiroshi Mohri, Junji Fujikawa, Hiro-o Nakagawa, Shigeki Sumida, Satoshi Yusa, Masashi Ohtsuki
  • Publication number: 20020119379
    Abstract: A photomask is produced which enables the simplification of the steps of lithography. A photomask is provided with shielding patterns made of shielding metallic thin film on a transparent substrate, wherein the photomask further comprises translucent patterns mainly including tantalum of materials selected from tantalum silicide, tantalum oxide, tantalum nitride or mixture thereof.
    Type: Application
    Filed: December 21, 2001
    Publication date: August 29, 2002
    Inventors: Kenji Noguchi, Toshiaki Motonaga, Hiro-o Nakagawa, Yasutaka Morikawa, Toshifumi Yokoyama, Takashi Tominaga, Yoshinori Kinase, Junji Fujikawa, Yoichi Takahashi
  • Publication number: 20020039689
    Abstract: A blank for halftone phase shift photomask is disclosed. The blank has a transparent substrate, a halftone phase shift layer and a light shielding film, the halftone phase shift layer and the light shielding film being layered in this order on the transparent substrate, and the l light shielding film is a single layered or multiple layered film which has a layer of tantalum.
    Type: Application
    Filed: April 26, 2001
    Publication date: April 4, 2002
    Inventors: Satoshi Yusa, Toshifumi Yokoyama, Shigeki Sumida, Toshiaki Motonaga, Yoshinori Kinase, Hiro-o Nakagawa, Chiaki Hatsuta, Junji Fujikawa, Masashi Ohtsuki
  • Publication number: 20010024552
    Abstract: A semiconductor laser and an optical waveguide device with an optical waveguide formed at a surface of its substrate are provided on a submount. The semiconductor laser and the optical waveguide device are mounted with an active layer and a surface at which the optical waveguide is formed facing the submount, respectively. The submount is combined with the semiconductor laser or the optical waveguide device to form one body using an adhesive with a spacer, which maintains a substantially uniform distance therebetween, being interposed therebetween, so that position adjustment in the height direction can be made automatically and mounting can be carried out with high-precision optical coupling. Thus, an optical waveguide device integrated module and a method of manufacturing the same are provided, in which a semiconductor laser and a planar optical waveguide device are mounted with their positions in the height direction controlled with high precision.
    Type: Application
    Filed: March 7, 2001
    Publication date: September 27, 2001
    Applicant: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yasuo Kitaoka, Toshifumi Yokoyama, Kazuhisa Yamamoto
  • Publication number: 20010005564
    Abstract: A blank for a halftone phase shift photomask in the present invention comprises a transparent substrate and a halftone phase shift film provided thereon, and said halftone phase shift film has a multilayer construction in which at least a first layer capable of being etched with a chlorinated gas and a second layer capable of being etched with a fluorinated gas are disposed in this order from the side near said transparent substrate. A film made of tantalum silicides is suitable to use as the second layer of the halftone phase shift film.
    Type: Application
    Filed: December 14, 2000
    Publication date: June 28, 2001
    Inventors: Toshiaki Motonaga, Toshifumi Yokoyama, Takafumi Okamura, Yoshinori Kinase, Hiroshi Mohri, Junji Fujikawa, Hiro-o Nakagawa, Shigeki Sumida, Satoshi Yusa, Masashi Ohtsuki
  • Patent number: 5972543
    Abstract: A phase shift mask, e.g. a halftone phase shift mask, which need not to form an ultra-fine pattern and is capable of suppressing during exposure the occurrence of a sub-peak of light intensity, which has an adverse effect on the image formation, and which has a light-blocking pattern with a reduced transmittance at a region outside a device pattern area which corresponds to a region subjected to multiple exposure during transfer effected by using the mask. The halftone phase shift mask has on a transparent substrate (101) a halftone phase shift film (102) comprising a single layer or a plurality of layers. The composition of the halftone phase shift film (102) is changed in a region (107) outside a device pattern area on the transparent substrate (101) which corresponds to a multiple-exposure region by a method wherein the region (107) is irradiated with an electromagnetic wave, a particle beam, heat rays, etc.
    Type: Grant
    Filed: June 19, 1998
    Date of Patent: October 26, 1999
    Assignee: Dai Nippon Printing Co., Ltd.
    Inventors: Toshifumi Yokoyama, Koichi Mikami, Chiaki Hatsuda, Hiroshi Mohri
  • Patent number: 5965301
    Abstract: A method for repairing a photomask by removing a residual defect in the photomask is provided which can solve problems, involved in repair of the photomask by the conventional laser beam irradiation, such as various types of maladjustments, limitation of focusing of a laser beam, creation of roughening in the repaired area, and problems, involved in repair of the photomask by focused ion beam irradiation, such as damage to a transparent substrate and a gallium stain.
    Type: Grant
    Filed: November 25, 1997
    Date of Patent: October 12, 1999
    Assignee: Dai Nippon Printing Co., Ltd.
    Inventors: Masami Nara, Toshifumi Yokoyama, Tsukasa Abe
  • Patent number: 5811208
    Abstract: A phase shift mask, e.g. a halftone phase shift mask, which need not to form an ultra-fine pattern and is capable of suppressing during exposure the occurrence of a sub-peak of light intensity, which has an adverse effect on the image formation, and which has a light-blocking pattern with a reduced transmittance at a region outside a device pattern area which corresponds to a region subjected to multiple exposure during transfer effected by using the mask. The halftone phase shift mask has on a transparent substrate (101) a halftone phase shift film (102) comprising a single layer or a plurality of layers. The composition of the halftone phase shift film (102) is changed in a region (107) outside a device pattern area on the transparent substrate (101) which corresponds to a multiple-exposure region by a method wherein the region (107) is irradiated with an electromagnetic wave, a particle beam, heat rays, etc.
    Type: Grant
    Filed: August 2, 1996
    Date of Patent: September 22, 1998
    Assignee: Dai Nippon Printing Co., Ltd.
    Inventors: Toshifumi Yokoyama, Koichi Mikami, Chiaki Hatsuda, Hiroshi Mohri
  • Patent number: 5723234
    Abstract: A phase shift photomask capable of being produced by dry etching with adequate in-plane uniformity of pattern dimension even if there is a large difference in exposed area ratio between different areas on the mask. In a phase shift photomask having an area provided with a phase shift layer which practically shifts the phase relative to another area, a dummy etching pattern (13) for dry etch rate correction is provided in an area other than a pattern exposure area (9 and 10), or a dummy etching pattern for dry etch rate correction having a size less than the limit of resolution attained by transfer is provided in the pattern exposure area, thereby reducing the etch rate nonuniformity due to the pattern density variation in the process of dry etching the phase shift photomask, and thus providing a phase shift photomask of high accuracy.
    Type: Grant
    Filed: February 28, 1996
    Date of Patent: March 3, 1998
    Assignee: Dai Nippon Printing Co., Ltd.
    Inventors: Toshifumi Yokoyama, Hiroyuki Miyashita