Dense plasma focus radiation source
AssigneeScience Research Laboratory, Inc.
InventorsJonah Jacob, Joseph A. Mangano, James Moran, Alexander Bykanov, Rodney Petr, Mordechai Rokni
Life of this patent
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Abstract
A dense plasma focus radiation source for generating EUV radiation using Lithium vapor and including a coaxially disposed anode and cathode. The invention includes methods and apparatuses for enhancing the efficiency of EUV radiation production, for protecting, cooling and extending the life of the anode and cathode, for protecting and shielding collecting optics from debris and pressure disturbances in the discharge chamber, and for feeding Lithium into the discharge chamber.
Claims126
A dense plasma focus radiation source comprising:
- an anode;
- a cathode;
- and
- a heat pipe constructed to bring a liquid element in close proximity to the anode, so as to cool the anode;
- wherein the dense plasma focus radiation source comprises a discharge circuit adapted to cause a plasma discharge, using Lithium vapor in a discharge chamber, between the anode and the cathode so as to generate extreme ultraviolet (EUV) radiation at electromagnetic wavelengths near 13.5 nm.
A dense plasma focus radiation source comprising:
- a plasma radiation source adapted to produce radiation and comprising a plasma pinch focus region;
- optical elements positioned near the plasma radiation source and adapted to receive at least some of the radiation produced by the plasma radiation source;
- and
- an optically transmissive barrier disposed between the plasma radiation source and the optical elements.
A dense plasma focus radiation source comprising:
- a plasma radiation source adapted to produce EUV radiation;
- a first gas jet providing a first gas stream at a first exit speed and having a first temperature;
- a second gas jet providing a second gas stream at a second exit speed substantially equal to the first exit speed and having a second temperature substantially equal to the first temperature, the first and second gas streams together comprising a gas curtain comprising a diffusion layer disposed between the first and second gas streams;
- and
- a first recovery duct positioned and sized so as to capture a substantial portion of the diffusion layer.
A dense plasma focus radiation source comprising:
- an anode and a cathode disposed in a coaxial arrangement about a longitudinal axis along a center of the anode;
- a discharge circuit adapted to cause a plasma discharge between the anode and the cathode so as to produce radiation;
- and
- a gas curtain comprising an axisymmetric flow pattern disposed above the anode;
- wherein the gas curtain comprises Lithium vapor.
A dense plasma radiation source comprising:
- a plasma radiation source adapted to produce EUV radiation and comprising a plasma pinch focus point;
- optical elements positioned above the plasma radiation source and adapted to receive at least some of the EUV radiation produced by the plasma radiation source;
- and
- a first web of refractory metal elements defining a series of open channels substantially aligned with the plasma pinch focus point and disposed between the plasma radiation source and the optical elements.
A method for cooling an anode of a plasma radiation source, the method comprising:
- bringing Lithium into close proximity with the anode using a heat pipe such that heat from the anode causes evaporation of the Lithium to a Lithium vapor in an evaporation region of the heat pipe, thereby cooling the anode;
- condensing the Lithium vapor to provide liquid Lithium;
- returning the liquid Lithium to the evaporation region of the heat pipe using a wick.
A method for protecting optical components in the vicinity of a plasma radiation source, the method comprising:
- providing a first vapor stream having a first temperature and a first exit speed between the optical components and the plasma radiation source;
- providing a second vapor stream comprising a noble gas in a substantially same location as the first vapor stream and in a same direction as the first vapor stream and having a substantially matching temperature and exit speed as the first vapor stream, such that a diffusion layer is formed between the first and second vapor streams;
- and
- recapturing at least a portion of the diffusion layer to recycle at least some of vapor forming the diffusion layer.
A method for protecting optical elements in the vicinity of a plasma radiation source, the method comprising:
- producing Lithium vapor in a discharge chamber of the plasma radiation source;
- providing for the Lithium vapor to flow upward in the discharge chamber;
- providing a downwardly-directed noble gas buffer flow in the discharge chamber, thereby creating a gas curtain comprised of the Lithium vapor and noble gas that shield the optical elements from the plasma radiation source.
In a radiation generating environment comprising a plasma radiation source and optical elements located above the plasma radiation source adapted to focus or direct the radiation, a method of protecting the optics comprising:
- providing an optically transmissive barrier between the plasma radiation source and the optical elements.
A method of producing EUV radiation using a dense plasma focus radiation source, including steps of:
- providing Lithium vapor in a discharge chamber of the dense plasma focus radiation source;
- and
- generating an electromagnetic (EM) field between an anode and a cathode of the dense plasma focus radiation source using a DPF pulsed discharge circuit so as to cause a plasma pinch at a tip of the anode, thereby producing the EUV radiation;
- wherein the step of providing the Lithium vapor includes extracting the Lithium vapor from a porous, Lithium-impregnated electrode by applying a pulsed radio frequency (RF) voltage across the anode and the porous, Lithium-impregnated electrode.
A dense plasma focus radiation source comprising:
- a radiation source including an anode and a cathode disposed coaxial with the anode in a discharge chamber, the radiation source adapted to generate EUV radiation using Lithium vapor extracted from the anode;
- a pulsed discharge circuit adapted to generate an electromagnetic (EM) field between the anode and the cathode so as to cause a plasma pinch at a tip of the anode, the plasma pinch generating the EUV radiation;
- and
- a radio frequency (RF) discharge circuit adapted to effect extraction of the Lithium vapor from the anode.
Dependencies are inferred from the claim text.