Patents by Inventor Hiroo Itoh

Hiroo Itoh 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).

  • Glass substrate for a mask blank, method of producing a glass substrate for a mask blank, mask blank, method of producing the mask blank, transfer mask, and method of producing a transfer mask
    Publication number: 20040137828
    Abstract: In a method of producing a glass substrate for an electronic device whereby to fabricate a glass substrate by carrying out a rough polishing step for polishing a surface of the glass substrate by using relatively large abrasive particles, then a precision polishing step for polishing it by using relatively small abrasive particles, a method of producing a glass substrate for an electronic device, and a photo mask blank and a method of producing a photo mask, wherein, before carrying out the precision polishing step, the surface of the glass substrate is etched (preferably etched with an alkaline aqueous solution) so as to elicit a crack extending in the depth direction from the surface of the glass substrate, the crack remaining after the precision polishing step, in a defect inspection step carried out after the precision polishing step.
    Type: Application
    Filed: July 15, 2003
    Publication date: July 15, 2004
    Applicant: HOYA CORPORATION
    Inventors: Kouji Takahashi, Hiroo Itoh