Electron beam gun
AssigneeNikon Corporation
InventorMamoru Nakasuji
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Abstract
Electron guns are disclosed that produce low-brightness and high-emittance electron beams that are suitable for use in an electron-beam reduction-lithography apparatus. A preferred embodiment comprises a cathode, a Wehnelt electrode, an anode, and at least one control electrode placed between the cathode and the anode. Each of these components defines a spherical surface all having a common center point and all thus being concentric with one another. During operation, the anode has a grounded electrical potential while the cathode and the Wehnelt electrode each have a potential of about -100 KV. If the applied voltage to the control electrode is adjusted within a range of -99 to -90 KV, the brightness can be controlled to within a range of 1.times.10.sup.3 to 2.times.10.sup.4 A/cm.sup.2.sr.
Claims25
An electron gun for reducing projection-microlithography system, the electron gun comprising on an optical axis:
- (a) a cathode comprising a planar or spherically concave electron-emission surface, the cathode being cylindrical relative to the optical axis;
- (b) an anode spaced from said cathode along the optical axis;
- (c) a Wehnelt electrode having a proximal portion proximal to the cathode and disposed around the cathode and having a distal portion between cathode and the anode and;
- (d) a control electrode situated between the cathode and the anode, the anode being structured and arranged so as to be electrically grounded during operation of the electron gun, the Wehnelt electrode being structured and arranged so as to have an electric potential, during operation of the electron gun, which potential tends to push electrons, in an electron beam emitted from the cathode, toward the optical axis.
An electron gun, comprising on an optical axis:
- (a) a cathode comprising a planar or spherically concave electron-emission surface;
- (b) an anode spaced from said cathode along the optical axis;
- (c) a Wehnelt electrode having a proximal portion proximal to the cathode and disposed around the cathode and having a distal portion between cathode and the anode;
- and
- (d) multiple control electrodes situated between the Wehnelt electrode and the anode, wherein, during operation of the electron gun, an electric field produced between the cathode and the anode is controlled by the control electrodes.
Dependencies are inferred from the claim text.