Patents by Inventor Tadashi Saga

Tadashi Saga 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: 20080063950
    Abstract: A photomask blank to be used as a material for a photomask is provided with a mask pattern having a transparent area and an effectively opaque area to exposure light on a transparent substrate. On the transparent board, one or more layers of light shielding films are formed with or without other film (A) in between, at least one layer (B) which constitutes the light shielding film includes silicon and a transition metal as main component, and a molar ratio of silicon to the transition metal is silicon:metal=4-15:1 (atomic ratio). The photomask provided with the mask pattern having the transparent area and the effectively opaque area to exposure light on the transparent board is also provided.
    Type: Application
    Filed: September 8, 2005
    Publication date: March 13, 2008
    Inventors: Hiroki Yoshikawa, Yukio Inazuki, Satoshi Okazaki, Takashi Haraguchi, Masahide Iwakata, Mikio Takagi, Yuichi Fukushima, Tadashi Saga
  • Publication number: 20070259276
    Abstract: A metal film is provided as a light shielding layer on one principle surface of a photomask substrate. The metal film cannot be substantially etched by chlorine-based dry etching containing oxygen ((Cl+O)-based dry etching) and can be etched by chlorine-based dry etching not containing oxygen (Cl-based dry etching) and fluorine-based dry etching (F-based dry etching). On the light shielding layer, a metal compound film as an antireflective layer. The metal compound film cannot be substantially etched by chlorine-based dry etching not containing oxygen (Cl based) and can be etched by at least one of chlorine-based dry etching containing oxygen ((Cl+O) based) and fluorine-based dry etching (F based).
    Type: Application
    Filed: August 10, 2005
    Publication date: November 8, 2007
    Inventors: Hiroki Yoshikawa, Yukio Inazuki, Yoshinori Kinase, Satoshi Okazaki, Takashi Haraguchi, Masahide Iwakata, Mikio Takagi, Yuichi Fukushima, Tadashi Saga
  • Publication number: 20070248897
    Abstract: A photomask blank has a light-shielding film composed of a single layer of a material containing a transition metal, silicon and nitrogen or a plurality of layers that include at least one layer made of a material containing a transition metal, silicon and nitrogen, and has one or more chrome-based material film. The high transition metal content ensures electrical conductivity, preventing charge-up in the photomask production process, and also provides sufficient chemical stability to cleaning in photomask production. The light-shielding film has a good resistance to dry etching of the chrome-based material film in the presence of chlorine and oxygen, thus ensuring a high processing accuracy.
    Type: Application
    Filed: April 19, 2007
    Publication date: October 25, 2007
    Inventors: Hiroki Yoshikawa, Yukio Inazuki, Satoshi Okazaki, Takashi Haraguchi, Tadashi Saga, Yuichi Fukushima
  • Publication number: 20070212618
    Abstract: A photomask blank is provided comprising an etch stop film which is disposed on a transparent substrate and is resistant to fluorine dry etching and removable by chlorine dry etching, a light-shielding film disposed on the etch stop film and including at least one layer composed of a transition metal/silicon material, and an antireflective film disposed on the light-shielding film. When the light-shielding film is dry etched to form a pattern, pattern size variation arising from pattern density dependency is reduced, so that a photomask is produced at a high accuracy.
    Type: Application
    Filed: March 8, 2007
    Publication date: September 13, 2007
    Inventors: Hiroki Yoshikawa, Yukio Inazuki, Satoshi Okazaki, Takashi Haraguchi, Tadashi Saga, Yosuke Kojima, Kazuaki Chiba, Yuichi Fukushima
  • Publication number: 20070212619
    Abstract: A photomask blank comprises a transparent substrate, a light-shielding film deposited on the substrate and comprising a metal or metal compound susceptible to fluorine dry etching, and an etching mask film deposited on the light-shielding film and comprising another metal or metal compound resistant to fluorine dry etching. When the light-shielding film is dry etched to form a pattern, pattern size variation arising from pattern density dependency is reduced, so that a photomask is produced at a high accuracy.
    Type: Application
    Filed: March 8, 2007
    Publication date: September 13, 2007
    Inventors: Hiroki YOSHIKAWA, Yukio INAZUKI, Satoshi OKAZAKI, Takashi HARAGUCHI, Tadashi SAGA, Yosuke KOJIMA, Kazuaki CHIBA, Yuichi FUKUSHIMA
  • Publication number: 20070020534
    Abstract: A light-shielding film for exposure light is formed on one principal plane of a transparent substrate made of quartz or the like that serves as a photomask substrate. The light-shielding film can serve not only as the so-called “light-shielding film” but also as an anti-reflection film. In addition, the light-shielding film has a total thickness of 100 nm or less, 70% or more of which is accounted for by the thickness of a chromium compound that has an optical density (OD) per unit thickness of 0.025 nm?1 for light having a wavelength of 450 nm. In the case where the photomask blank is used for fabricating a mask designed for ArF exposure, the thickness and composition of the light-shielding film are selected in such a manner that the OD of the light-shielding film is 1.2 to 2.3 for 193 or 248 nm wavelength light.
    Type: Application
    Filed: July 20, 2006
    Publication date: January 25, 2007
    Inventors: Hiroki Yoshikawa, Hiroshi Kubota, Yoshinori Kinase, Satoshi Okazaki, Tamotsu Maruyama, Takashi Haraguchi, Masahide Iwakata, Yuichi Fukushima, Tadashi Saga
  • Publication number: 20050244722
    Abstract: In a halftone phase shift mask blank comprising a substrate, a light absorbing film, and a phase shifter film, the light absorbing film contains a metal element of Group 4A in a distribution having a higher metal element content in an upper region than in a lower region. Also provided is a halftone phase shift mask blank comprising a transparent substrate and a halftone phase shift film of a single layer or multiple layers having a preselected phase difference and transmittance, wherein at least one layer of the halftone phase shift film contains at least 90 atom % of silicon and a plurality of metal elements, typically Mo and Zr or Hf.
    Type: Application
    Filed: March 30, 2005
    Publication date: November 3, 2005
    Applicants: Shin-Etsu Chemical Co., Ltd., Toppan Printing Co., Ltd.
    Inventors: Kimihiro Okada, Masahide Iwakata, Takashi Haraguchi, Mikio Takagi, Yuichi Fukushima, Hiroki Yoshikawa, Toshinobu Ishihara, Satoshi Okazaki, Yukio Inazuki, Tadashi Saga
  • Publication number: 20050217988
    Abstract: For the manufacture of a halftone phase shift mask blank comprising a transparent substrate and a translucent film of one or more layers having a controlled phase and transmittance, at least one layer of the translucent film comprising Si, Mo and Zr at the same time, a target comprising at least Zr and Mo in a molar ratio Zr/Mo between 0.05 and 5 is useful.
    Type: Application
    Filed: March 30, 2005
    Publication date: October 6, 2005
    Applicants: Shin-Etsu Chemical Co., Ltd., Toppan Printing Co., Ltd.
    Inventors: Hiroki Yoshikawa, Toshinobu Ishihara, Satoshi Okazaki, Yukio Inazuki, Tadashi Saga, Kimihiro Okada, Masahide Iwakata, Takashi Haraguchi, Yuichi Fukushima
  • Publication number: 20050112477
    Abstract: In a phase shift mask blank comprising a phase shift multilayer film on a substrate, the phase shift multilayer film consists of at least one layer of light absorption function film and at least one layer of phase shift function film, and the light absorption function film has an extinction coefficient k which increases as the wavelength changes from 157 nm to 260 nm, and has a thickness of up to 15 nm. The phase shift mask blank has minimized wavelength dependency of transmittance and can be processed with a single dry etching gas.
    Type: Application
    Filed: October 21, 2004
    Publication date: May 26, 2005
    Applicants: Shin-Etsu Chemical Co., Ltd., Toppan Printing Co., Ltd.
    Inventors: Hiroki Yoshikawa, Yukio Inazuki, Satoshi Okazaki, Takashi Haraguchi, Yuichi Fukushima, Yoshihiro Ii, Tadashi Saga