Title:
SILICA GLASS SHEET AND METHOD FOR REDUCING BIREFRINGENCE OF SILICA GLASS SHEET
Document Type and Number:
Japanese Patent JP2019099415
Kind Code:
A
Abstract:
To provide a silica glass sheet used in optical lithography and having birefringence amount of a silica glass surface vertical to a transmission direction of a light simply controlled to 2.0 nm/cm or less, and a method for reducing birefringence of the silica glass sheet.SOLUTION: The silica glass sheet is a silica glass used in an optical lithography process with a vacuum ultraviolet light as a light source, content of fluorine is 1 wt.% to 5 wt.%, birefringence amount of a silica glass surface (utilized surface) vertical to a transmission direction of a light is simply controlled to 2.0 nm/cm or less when irradiated with an ultraviolet light with 193 nm as exposure wavelength of optical lithography, and birefringence when the silica glass surface in parallel to the transmission direction of the light is irradiated with a light vertically is larger than birefringence of the vertical silica glass surface.SELECTED DRAWING: None
Inventors:
FUKAZAWA YUJI
Application Number:
JP2017231529A
Publication Date:
June 24, 2019
Filing Date:
December 01, 2017
Export Citation:
Assignee:
COORSTEK KK
International Classes:
C03C3/06; C03B20/00; G03F7/20
Attorney, Agent or Firm:
Kinoshita Shigeru
Yuko Sawada
Yuko Sawada