Patents by Inventor Yasushi Tohma

Yasushi Tohma 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: 20080121529
    Abstract: A flattening method can flatly process a surface of a metal film as an interconnect material over the entire film surface at a sufficiently high processing rate even when the metal film has initial surface irregularities. The flattening method for processing and flattening a surface of a metal film formed on a workpiece and having initial surface irregularities, including: coating only recessed portions of the initial surface irregularities of the metal film with a solid or pasty coating material; and processing the surface of the metal film by electrolytic processing using no abrasive.
    Type: Application
    Filed: December 21, 2005
    Publication date: May 29, 2008
    Inventors: Yasushi Tohma, Takayuki Saitoh, Tsukuru Suzuki, Akira Kodera, Yutaka Wada, Itsuki Kobata
  • Patent number: 6627095
    Abstract: A magnetic recording disk having on its surface a texture structure of fine surface irregularities with reduced variations, which is suitable for high-density magnetic recording, and a method of manufacturing such a magnetic recording disk are provided. A magnetic recording disk has a substrate 11, 12 (16) coated on a surface thereof with a magnetic layer 13, a carbon layer 14, and a lubricating film 15. The substrate has on a surface thereof a texture structure of fine surface irregularities for reducing friction when the substrate is brought into contact with a head and controlling an amount of lift of the head. The fine surface irregularities have a height of 20 nm or less and are formed from a pattern shape or profile of a shield with a high-speed atomic beam emitted from a high-speed atomic beam source.
    Type: Grant
    Filed: December 19, 2000
    Date of Patent: September 30, 2003
    Assignee: Ebara Corporation
    Inventors: Masahiro Hatakeyama, Katsunori Ichiki, Kenji Watanabe, Kazuo Yamauchi, Shinta Kunitomo, Yasushi Tohma, Tohru Satake
  • Patent number: 6468598
    Abstract: It is an object of the present invention to provide a method of making a magnetic disk having a uniform textured structure with micro-waviness of fabrication depth of less than 20 nm, preferably less than 10 nm, and a local depth deviation of less than 5%, in which texture patterns are characterized by the fact that lateral surfaces of the structure are sloped or curved. The object has been achieved in a method for making a magnetic disk, having micro-waviness on a fabrication surface of a substrate for reducing dynamic friction and controlling head float, by rotating and irradiating the fabrication surface with a high energy beam from a beam surface at an inclined angle to the substrate surface. The surface is irradiated through a shielding mask having a specific pattern, so as to produce a transcription pattern on the substrate surface to produce a textured structure with micro-waviness having sloped or curved side surfaces.
    Type: Grant
    Filed: June 22, 2000
    Date of Patent: October 22, 2002
    Assignee: Ebara Corporation
    Inventors: Masahiro Hatakeyama, Katsunori Ichiki, Kenji Watanabe, Kazuo Yamauchi, Shinta Kunitomo, Tohru Satake, Yasushi Tohma, Juichi Ishiguro
  • Publication number: 20010016235
    Abstract: A magnetic recording disk having on its surface a texture structure of fine surface irregularities with reduced variations, which is suitable for high-density magnetic recording, and a method of manufacturing such a magnetic recording disk are provided.
    Type: Application
    Filed: December 19, 2000
    Publication date: August 23, 2001
    Inventors: Masahiro Hatakeyama, Katsunori Ichiki, Kenji Watanabe, Kazuo Yamauchi, Shinta Kunitomo, Yasushi Tohma, Tohru Satake
  • Patent number: 6194048
    Abstract: A magnetic recording disk having on its surface a texture structure of fine surface irregularities with reduced variations, which is suitable for high-density magnetic recording, and a method of manufacturing such a magnetic recording disk are provided. The magnetic recording disk has a substrate 11, 12 (16) coated on a surface thereof with a magnetic layer 13, a carbon layer 14, and a lubricating film 15. The substrate has on a surface thereof a texture structure of fine surface irregularities for reducing friction when the substrate is brought into contact with a head and controlling an amount of lift of the head. The fine surface irregularities have a height of 20 nm or less and are formed from a pattern shape or profile of a shield with a high-speed atomic beam emitted from a high-speed atomic beam source.
    Type: Grant
    Filed: October 2, 1998
    Date of Patent: February 27, 2001
    Assignee: Ebara Corporation
    Inventors: Masahiro Hatakeyama, Katsunori Ichiki, Kenji Watanabe, Kazuo Yamauchi, Shinta Kunitomo, Yasushi Tohma, Tohru Satake
  • Patent number: 6099698
    Abstract: It is an object of the present invention to provide a method of making a magnetic disk having a uniform textured structure with micro-waviness of fabrication depth of less than 20 nm, preferably less than 10 nm, and a local depth deviation of less than 5%, in which texture patterns are characterized by the fact that lateral surfaces of the structure are sloped or curved. The object has been achieved in a method for making a magnetic disk having micro-waviness on a fabrication surface of a substrate for reducing dynamic friction and controlling head float, by rotating and irradiating the fabrication surface with a high energy beam from a beam source at an inclined angle to the substrate surface, through a shielding mask having a specific pattern, so as to process a transcription pattern on the substrate surface to produce a textured structure with micro-waviness having sloped or curved side surfaces.
    Type: Grant
    Filed: October 2, 1998
    Date of Patent: August 8, 2000
    Assignee: Ebara Corporation
    Inventors: Masahiro Hatakeyama, Katsunori Ichiki, Kenji Watanabe, Kazuo Yamauchi, Shinta Kunitomo, Tohru Satake, Yasushi Tohma, Juichi Ishiguro