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US 6,087,667 AGranted
Charged-particle-beam (CPB) lithography apparatus, evaluation method, and CPB source
AssigneeNikon Corporation
InventorsMamoru Nakasuji, Shintaro Kawata
Life of this patent
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Abstract
Charged-particle-beam (CPB) lithography apparatus are disclosed that provide high accuracy in forming, by projection exposure using a charged particle beam, a pattern on a sensitive substrate at high throughput. The apparatus comprise a cathode having a work function of 2.65 eV or less within a space-charge limitation region. The temperature of the cathode is controlled within a range of 1,200 to 1,400.degree. C.
Claims38
A charged-particle-beam source for use in charged-particle-beam projection lithography, comprising:
- (a) a cathode configured to produce a charged particle beam having a cathode current, the cathode maintained at a cathode voltage;
- (b) an anode and a control-anode maintained at an anode voltage and control-anode voltage, respectively;
- and
- (c) a power supply configured to maintain the cathode voltage, the anode voltage, and the control-anode voltage and to adjust at least one of the cathode current, the cathode voltage, and the control-anode voltage to produce a space-charge limitation region between the cathode and the control-anode.
1 more element
A charged-particle-beam lithography apparatus, comprising:
- (a) a charged-particle-beam source that produces a beam of charged particles having a cathode current, the charged-particle-beam source comprising a charged-particle-emission plane;
- (b) at least two condenser lenses;
- (c) a charged-particle-beam optical system configured to direct the beam of charged particles from the source through the condenser lenses and a reticle and from the reticle to a sensitive substrate;
- (d) the charged-particle-beam source comprising an anode, a control-anode, and a cathode that produces the cathode current;
- (e) a power supply that maintains the cathode, anode, and the control-anode at a cathode voltage, an anode voltage, and a control-anode voltage, respectively, wherein the power supply is configured to control at least one of the cathode current, the cathode voltage, and the control-anode voltage to produce a space-charge limitation region between the cathode and the control-anode when the cathode is energized to produce the charged particle beam;
- and
- (f) a symmetric magnetic doublet lens system situated between the reticle and the substrate, the symmetric magnetic doublet lens system being configured to produce a reduced image of the reticle on the substrate.
4 more elements
A charged-particle-beam lithography apparatus, comprising:
- (a) a charged-particle-beam source configured to produce a beam of charged particles, the charged-particle-beam source comprising a cathode with a charged-particle-emission plane;
- (b) a charged-particle-beam optical system comprising at least two condenser lenses and configured to direct the beam of charged particles from the source through the condenser lenses and then a reticle and from the reticle to a sensitive substrate;
- (c) an anode and a control-anode electrode, the control-anode electrode being configured to be charged with an electrode potential having a ratio of electric-potential fluctuation with respect to the cathode of no greater than 10.sup.-4 ;
- (d) the charged-particle-beam optical system further comprises a symmetric magnetic doublet lens system configured to form a reduced image of the reticle on the substrate;
- and
- (e) a power supply configured to control a brightness of the charged-particle-beam by establishing a space-charge limitation region between the cathode and the control-anode electrode and by varying the control-anode electrode potential.
3 more elements
A method of controlling a charged-particle-beam source, comprising:
- providing a cathode that emits a charged-particle beam having a beam current;
- providing an anode and a control-anode;
- maintaining the cathode at a cathode voltage;
- maintaining the anode at an anode voltage and the control-anode at a control-anode voltage;
- and
- adjusting at least one of the cathode current, the cathode voltage, and the control-anode voltage to produce a space-charge limitation region between the cathode and the control-anode.
3 more elements
A method of controlling a charged-particle-beam source comprising a cathode, an anode, and a control-anode, the method comprising:
- (a) producing a cathode current with a charged-particle-beam source that produces a beam of charged particles, the charged-particle-beam source comprising a charged-particle-emission plane;
- (b) providing at least two condenser lenses;
- (c) providing a charged-particle-beam optical system configured to direct the beam of charged particles from the source through the condenser lenses and a reticle and from the reticle to a sensitive substrate;
- (d) maintaining the cathode, the anode, and the control-anode at a cathode voltage, an anode voltage, and a control-anode voltage, respectively;
- (e) selecting the cathode current and at least one of the cathode voltage, the anode voltage, and the control-anode voltage to produce a space-charge limitation region between the cathode and the control-anode when the cathode is energized to produce the charged particle beam;
- and
- (f) producing a reduced image of the reticle on the substrate.
4 more elements
A method of exposing a sensitive substrate with a charged-particle beam, the method comprising:
- (a) providing a charged-particle-beam source comprising a cathode, an anode, a control-anode, and a charged-particle-emission plane;
- (b) producing a cathode current with a charged-particle-beam source;
- (c) providing at least two condenser lenses;
- (d) providing a charged-particle-beam optical system configured to direct the beam of charged particles from the source through the condenser lenses and a reticle and from the reticle to the sensitive substrate;
- (f) maintaining the cathode, the anode, and the control-anode at a cathode voltage, an anode voltage, and a control-anode voltage, respectively;
- (g) selecting the cathode current and at least one of the cathode voltage, the anode voltage, and the control-anode voltage to produce a space-charge limitation region between the cathode and the control-anode when the cathode is energized to produce the charged particle beam;
- and
- (h) producing a reduced image of the reticle on the substrate.
5 more elements
Dependencies are inferred from the claim text.