Immersion lens and electron beam projection system using the same
AssigneeAdvantest Corporation
InventorHitoshi Tanaka
Life of this patent
Estimating the term…
Abstract
An immersion lens comprising a first magnetic lens unit for generating a first magnetic field and a second magnetic lens unit for generating a second magnetic field is disclosed. The combined magnetic field of the first and second magnetic fields converges the electron beam between the first magnetic lens unit and the second magnetic lens unit. The immersion lens is reduced in size by configuring the second magnetic lens of a permanent magnet.
Claims6
An immersion lens comprising:
- a first magnetic lens having a bore for passing the incident electron beam and generating a first magnetic field;
- and
- a second magnetic lens for generating a second magnetic field for converging said electron beam;
- wherein the combined magnetic field of said first and second magnetic fields converges said electron beam between said first magnetic lens and said second magnetic lens, characterized in that said second magnetic lens includes a permanent magnet;
- and
- wherein said second magnetic lens includes an auxiliary coil and a yoke arranged around said permanent magnet.
An electron beam projection system comprising an electron gun for generating an electron beam, and an immersion lens for converging said electron beam generated by said electron gun, a specimen being irradiated with said electron beam converged by said immersion lens;
- wherein said immersion lens includes:
- a first magnetic lens arranged adjacent an upper surface of said specimen which faces said electron gun, said first magnetic lens having a bore through which said electron beam is passed and generating a first magnetic field;
- and
- a second magnetic lens being arranged on the opposite side of said specimen relative to the first magnetic lens, said second magnetic lens including a solid-cylindrical permanent magnet, and an auxiliary coil and a yoke arranged around said permanent magnet for adjusting the magnetic field generated by said permanent magnet and generating a second magnetic field,
- wherein a combined magnetic field of said first and second magnetic fields converges said electron beam between said first magnetic lens and said second magnetic lens.
An immersion lens comprising:
- a first magnetic lens having a bore for passing the incident electron beam and generating a first magnetic field;
- and
- a second magnetic lens for generating a second magnetic field;
- wherein the combined magnetic field of said first and second magnetic fields converges said electron beam between said first magnetic lens and said second magnetic lens;
- and
- wherein said second magnetic lens comprises a solid-cylindrical permanent magnet, and an auxiliary coil and a yoke arranged around said permanent magnet for adjusting the magnetic field generated by said permanent magnet.
Dependencies are inferred from the claim text.