Title:
ELECTRON BEAM EXPOSURE DEVICE
Document Type and Number:
Japanese Patent JPS5957425
Kind Code:
A
Abstract:
PURPOSE:To adjust the focus at high speed with excellent response capability, and to improve accuracy on exposure by making the wall thickness of an optical lens-barrel in a section, to which a dynamic focus coil is provided, thinner than the thickness detected by a specific formula. CONSTITUTION:Main polariscopes 2, 3 for scanning electron beams on a sample are arranged to a lower section in the lens-barrel 1, objectives 5 for focussing and irradiating electron beams on a target 4 are disposed where approximately the same as the main polariscopes 2, 3, and the dynamic focus coil 6 for focussing electron beams is arranged to an upper section on the outside. The wall thickness L of the section to which the dynamic focus coil 6 is disposed is formed in size thinner than the thickness 1/(2pifsigmamu)1/2 of a skin effect. Where f shall be the response frequency of the dynamic focus coil 6, sigma the conductivity of the lens-barrel 1 and mu the permeability of the lens-barrel 1. When the optical lens-barrel 1 is formed by a Ti alloy, conductivity sigma can be reduced, and wall thickness L is unnecessitated to be thin extremely.
Inventors:
NAKASUJI MAMORU
Application Number:
JP16880482A
Publication Date:
April 03, 1984
Filing Date:
September 28, 1982
Export Citation:
Assignee:
TOSHIBA KK
International Classes:
H01J37/305; G03F7/20; H01J37/141; H01J37/30; H01L21/027; (IPC1-7): G03F7/20; H01J37/305
Attorney, Agent or Firm:
Takehiko Suzue