Patents Assigned to Clean Surface Technology Co.
  • Patent number: 9280045
    Abstract: The present invention is to provide a mask blank enabling fabrication of a photomask having a structure where electrostatic breakdown is effectively prevented. To accomplish the object, the invention discloses a mask blank comprising a mask substrate, an electrostatic breakdown prevention film fully covering one side of the mask substrate, and a shading film formed on the electrostatic breakdown prevention film. The electrostatic breakdown prevention film is made of titanium, tantalum, titanium compound or tantalum compound. The transparent rate of the electrostatic breakdown prevention film is not less than 75%, for the wavelength of light in an exposure. The sheet resistance of the electrostatic discharge prevention film is not more than 100K?/?.
    Type: Grant
    Filed: October 15, 2013
    Date of Patent: March 8, 2016
    Assignee: CLEAN SURFACE TECHNOLOGY CO.
    Inventor: Isao Hattori
  • Publication number: 20140106266
    Abstract: The present invention is to provide a mask blank enabling fabrication of a photomask having a structure where electrostatic breakdown is effectively prevented. To accomplish the object, the invention discloses a mask blank comprising a mask substrate, an electrostatic breakdown prevention film fully covering one side of the mask substrate, and a shading film formed on the electrostatic breakdown prevention film. The electrostatic breakdown prevention film is made of titanium, tantalum, titanium compound or tantalum compound. The transparent rate of the electrostatic breakdown prevention film is not less than 75%, for the wavelength of light in an exposure. The sheet resistance of the electrostatic discharge prevention film is not more than 100K?/?.
    Type: Application
    Filed: October 15, 2013
    Publication date: April 17, 2014
    Applicant: CLEAN SURFACE TECHNOLOGY CO.
    Inventor: Isao Hattori
  • Patent number: 4646418
    Abstract: A carrier for a flat photomask substrate having peripheral edges comprises a frame, a handle, a shaft, primary rings, and a spring. The frame has two ends, a periphery, and a shape with one side open. The handle has two ends and is journaled to one of the two ends of the frame. The shaft is provided through the one end of the frame and one end of the handle. This shaft allows the one end of the frame to pivot in a freely rotatable manner about the one end of the handle. The primary rings are arranged at the other end of the frame and at the one end of the handle. Such primary rings support the peripheral edges of the flat photomask substrate. The spring extends between the one end of the frame and the one end of the handle. This spring presses the primary rings into contact with the peripheral edges of the flat photomask substrate.
    Type: Grant
    Filed: December 6, 1985
    Date of Patent: March 3, 1987
    Assignee: Clean Surface Technology Co.
    Inventor: Isao Hattori