Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05G—X-RAY TECHNIQUE
  • H05G2/00—Apparatus or processes specially adapted for producing X-rays, not involving X-ray tubes, e.g. involving generation of a plasma
  • H05G2/001—Production of X-ray radiation generated from plasma
  • H05G2/003—Production of X-ray radiation generated from plasma the plasma being generated from a material in a liquid or gas state
  • H05G2/006—Production of X-ray radiation generated from plasma the plasma being generated from a material in a liquid or gas state details of the ejection system, e.g. constructional details of the nozzle
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B1/00—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means
  • B05B1/02—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to produce a jet, spray, or other discharge of particular shape or nature, e.g. in single drops, or having an outlet of particular shape
  • B05B1/08—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to produce a jet, spray, or other discharge of particular shape or nature, e.g. in single drops, or having an outlet of particular shape of pulsating nature, e.g. delivering liquid in successive separate quantities ; Fluidic oscillators
  • B05B1/083—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to produce a jet, spray, or other discharge of particular shape or nature, e.g. in single drops, or having an outlet of particular shape of pulsating nature, e.g. delivering liquid in successive separate quantities ; Fluidic oscillators the pulsating mechanism comprising movable parts
  • B05B1/086—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to produce a jet, spray, or other discharge of particular shape or nature, e.g. in single drops, or having an outlet of particular shape of pulsating nature, e.g. delivering liquid in successive separate quantities ; Fluidic oscillators the pulsating mechanism comprising movable parts with a resiliently deformable element, e.g. sleeve
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B17/00—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups
  • B05B17/04—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods
  • B05B17/06—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods using ultrasonic or other kinds of vibrations
  • B05B17/0607—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods using ultrasonic or other kinds of vibrations generated by electrical means, e.g. piezoelectric transducers
  • B05B17/0623—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods using ultrasonic or other kinds of vibrations generated by electrical means, e.g. piezoelectric transducers coupled with a vibrating horn
  • B05B17/063—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods using ultrasonic or other kinds of vibrations generated by electrical means, e.g. piezoelectric transducers coupled with a vibrating horn having an internal channel for supplying the liquid or other fluent material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B17/00—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups
  • B05B17/04—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods
  • B05B17/06—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods using ultrasonic or other kinds of vibrations
  • B05B17/0607—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods using ultrasonic or other kinds of vibrations generated by electrical means, e.g. piezoelectric transducers
  • B05B17/0653—Details
  • B05B17/0669—Excitation frequencies
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B17/00—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups
  • B05B17/04—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods
  • B05B17/06—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods using ultrasonic or other kinds of vibrations
  • B05B17/0607—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods using ultrasonic or other kinds of vibrations generated by electrical means, e.g. piezoelectric transducers
  • B05B17/0653—Details
  • B05B17/0661—Transducer materials

Definitions

• the target supply apparatus may be used to generate targets in an extreme ultraviolet (EUV) light source.
• EUV extreme ultraviolet
• a target apparatus may be used to produce a stream or jet of fluid material.
• the nozzle apparatus may be used to produce targets that are converted to plasma that emits extreme ultraviolet (EUV) light.
• EUV extreme ultraviolet
• EUV light may be, for example, electromagnetic radiation having wavelengths of 100 nanometers (nm) or less (also sometimes referred to as soft x-rays), and including light at a wavelength of, for example, 20 nm or less, between 5 and 20 nm, or between 13 and 14 nm, may be used in photolithography processes to produce extremely small features in substrates, for example, silicon wafers, by initiating polymerization in a resist layer.
• Methods to produce EUV light include, but are not necessarily limited to, converting a material that includes an element, for example, xenon, lithium, or tin, with an emission line in the EUV range in a plasma state.
• the required plasma may be produced by irradiating a target material, for example, in the form of a droplet, plate, tape, stream, or cluster of material, with an amplified light beam that may be referred to as a drive laser.
• a target material for example, in the form of a droplet, plate, tape, stream, or cluster of material
• an amplified light beam that may be referred to as a drive laser.
• the plasma is typically produced in a sealed vessel, for example, a vacuum chamber, and monitored using various types of metrology equipment.
• a system includes: a conduit including an orifice configured to fluidly couple to a reservoir and to emit molten target material; an actuator including at least a first zone and a second zone that is between the first zone and the orifice, where motion of the first zone and the second zone is transferred to an interior of the conduit; and a controller configured to apply a first actuation signal to the first zone and a second actuation signal to the second zone.
• the second actuation signal has a higher frequency than the first actuation signal.
• Implementations may include one or more of the following features.
• the second zone may be smaller than the first zone.
• the system also may include a plurality of actuator electrodes.
• at least one actuator electrode may be associated with each of the first zone and the second zone; each of the first actuation signal and the second actuation signal may include an electrical signal having a frequency spectrum; and, to apply a particular actuation signal to a particular zone of the actuator, the controller may be configured to apply an electrical signal to the actuator electrode associated with the particular zone.
• the frequency spectrum of at least one electrical signal may include more than one frequency.
• the actuator may include a single piece of material mounted to an exterior of the conduit; the actuator electrodes may be on an exterior of the actuator, and the actuator electrodes may be spatially separated from each other.
• the actuator includes a tube, the tube including: a first end; a second end; an inner wall that extends from the first end to the second end and is mechanically coupled to the exterior of the conduit; the second end is closer to the orifice than the first end; the first zone of the actuator is a first portion of the tube, and the second zone of the actuator is a second portion of the tube; and at least one surface feature is formed on the exterior of the actuator between the first zone and the second zone, and each surface feature is configured to provide partial mechanical isolation between the first zone and the second zone.
• the at least one surface feature may include at least one groove that is recessed into the exterior surface.
• the at least one surface features may include a plurality of grooves; each groove may surround the tube; and each groove may have a groove shape.
• the system also may include a ground electrode on the first end and inner wall of the tube.
• One of the plurality of grooves is between the ground electrode and the first zone.
• at least one of the plurality of grooves has a different shape than at least other groove.
• the diameter of the outer wall of the tube may be smaller at the second end than the first end.
• each actuator electrode surrounds the associated zone.
• a minimum frequency in the frequency spectrum of the second actuation signal is greater than a maximum frequency in the frequency spectrum of the first actuation signal.
• a maximum frequency in the second frequency spectrum may be greater than a maximum frequency in the first frequency spectrum.
• the controller being configured to apply the first actuation signal and the second actuation signal may include the controller being configured to control an electrical signal generator such that the first actuation signal and the second actuation signal are generated and applied to the respective first zone and second zone.
• Each of the first actuation signal and the second actuation signal may include at least one sine wave.
• the system also may include the electrical signal generator.
• the molten target material may emit extreme ultraviolet light when in a plasma state.
• the first zone of the actuator may include a first actuator and the second actuator may be distinct from the first actuator.
• the system also may include a membrane in mechanical communication with an interior of the conduit; and the second actuator may be mechanically coupled to the membrane.
• the system may include a motion transfer block between the first actuator and the second actuator.
• the first actuator may include a stack of actuation elements.
• a method in another aspect, includes: fluidly coupling an orifice of a conduit to a reservoir that holds molten target material; applying pressure to the reservoir such that the molten target material flows in the conduit; applying a first actuation signal to a first zone of an actuator that is mechanically coupled to the conduit, the first actuation signal having a first frequency spectrum; and applying a second actuation signal to a second zone of the actuator.
• the second actuation signal has a second frequency spectrum, and the second frequency spectrum includes higher frequencies than the first frequency spectrum.
• Implementations may include one or more of the following features.
• a third actuation signal may be applied to a third zone of the actuator, the third actuation signal having a third frequency spectrum.
• a system in another aspect, includes: a conduit including an orifice configured to fluidly couple to a reservoir and to emit molten target material; a single -piece actuator mechanically coupled to the conduit, the single-piece actuator including a plurality of separately controllable zones; and a controller configured to apply a separate actuation signal to each of at least a first zone and a second zone.
• a groove is formed in an exterior surface of the single-piece actuator between the first zone and the second zone, and the groove is configured to partially mechanically decouple the first zone and the second zone.
• a system in another aspect, includes: a conduit including an orifice configured to fluidly couple to a reservoir and to emit molten target material; an actuator mechanically coupled to the conduit, the actuator including a plurality of separately controllable zones, the plurality of separately controllable zones including at least a first zone and a second zone, the second zone is between the first zone and the orifice; and the second zone is smaller than the first zone; and a controller configured to apply a first actuation signal to the first zone and a second actuation signal to the second zone.
• the second actuation signal includes at least one frequency that is greater than all of the frequencies in the first actuation signal.
• an actuator in another aspect, includes: an actuator body including: a ground zone configured to be electrically connected to a reference potential; and a plurality of controllable zones. Each controllable zone is configured to receive a control signal, and in operational use, the controllable zones are configured to be mechanically coupled to a conduit such that the motion of the controllable zones generates pressure waves in an interior region of the conduit.
• the actuator body may include a single piece of material; the ground zone and the plurality of controllable zones may be part of the single piece of material; and the single piece of material may be a plurality of spatial features; and the ground zone may separated from the plurality of controllable zones by one of the plurality of spatial features, and each controllable zone may be separated from a nearest controllable zone by one of the plurality of spatial features.
• At least one of the controllable zones may be a separate piece of material that does not directly contact any of the other controllable zones or the ground zone.
• the actuator body may include a a substantially cylindrical sidewall that is configured to surround the conduit.
• Implementations of any of the techniques described above may include an EUV light source, a target supply system, a method, a process, a controller or a control system that acts on an actuator or a target supply apparatus, a device, or an apparatus.
• the details of one or more implementations are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.
• FIG. 1 is a block diagram of an example of an EUV light source.
• FIG. 2A is a side cross-sectional block diagram of an example of a target formation apparatus in an X-Z plane.
• FIG. 2B is a cross-sectional view of the target formation apparatus of FIG. 2A in an Y-Z plane taken along the line 2B’ — 2B’.
• FIG. 3 is a side cross-sectional block diagram of another example of a target formation apparatus in an X-Z plane.
• FIG. 4 is a side cross-sectional block diagram of another example of a target formation apparatus in an X-Z plane.
• FIG. 5 is a side cross-sectional block diagram of another example of a target formation apparatus in an X-Z plane.
• FIG. 6 is a side cross-sectional block diagram of an example of an actuator assembly.
• FIG. 7 is a side cross-sectional block diagram of another example of a target formation apparatus in an X-Z plane.
• FIG. 8 is a block diagram of an example of an EUV light source.
• FIG. 1 a block diagram of an EUV light source 100 that includes a supply system 110 is shown.
• the supply system 110 emits a stream 121 of targets such that a target 121p is delivered to a plasma formation location 123 in a vacuum chamber 109.
• the target 121p includes target material, which is any material that emits EUV light 197 when in a plasma state.
• the target material may include water, tin, lithium, and/or xenon.
• the plasma formation location 123 receives a light beam 106.
• the light beam 106 is generated by an optical source 105 and delivered to the vacuum chamber 109 via an optical path 107.
• An interaction between the light beam 106 and the target material in the target 121p produces a plasma 196 that emits EUV light 197.
• the supply system 110 includes a conduit 114 that defines an orifice 119.
• the conduit 114 is mounted to the supply system 110 with a nozzle mount or housing 117.
• the interior of the conduit 114 and the orifice 119 are fluidly coupled to a reservoir 112 that holds target material under pressure P.
• P exceeds the pressure in the vacuum chamber 109
• the target material flows into the conduit 114 and exits through the orifice 119 as a jet or continuous stream 124 of target material.
• the jet 124 of target material breaks up into individual droplets that coalesce into a stream 121 of larger droplets that arrive at the plasma formation location 123.
• the conduit 114 is coupled to an actuator 193, which is controlled by a controller 190. The motion of the actuator 193 is transferred to the conduit 114 to create acoustic waves inside the conduit 114.
• the controller 190 may include, for example, an electronic processing module, electronic storage, and/or a function or signal generator that produce control signals.
• the controller 190 controls a separate device, such as a voltage or current source, to generate control signals that are applied to the actuator 192.
• the controller 190 may control a voltage source to generate control signals in the form of voltage and or current signals having particular amplitude, frequency, and/or phase values.
• the controller 190 controls the characteristics (for example, amplitude and or frequency) of the motion of the actuator 193 and thus also controls the characteristics of the acoustic waves inside the conduit 114.
• the rate at which the larger, coalesced droplets arrive at the plasma formation location 123 is determined by the characteristics of the acoustic waves inside the conduit 114.
• the controller 190 is also configured to control properties of the droplets in the stream 121.
• the final targets may be generated at frequencies of, for example, between 40 to 300 kHz and may travel toward the plasma formation location 123 at a velocity of, for example, between 40 and 120 meters per second (m/s) or up to 500 m/s.
• the spatial separation between two adjacent targets in the stream 121 of targets may be, for example, between 1 and 3 millimeters (mm). Between 50 and 300 initial droplets (also called Rayleigh droplets) may coalesce to form a single larger target.
• the actuator 193 has two or more zones that are separately controlled by the controller 190. As discussed below, having two or more separately controllable zones improves the performance of the actuator 193 and the supply system 110.
• the actuator 193 includes a first zone 194a and a second zone 194b.
• the second zone 194b is between the orifice 119 and the first zone 194a.
• the second zone 194a is relatively near to the orifice 119 and the first zone 194a is farther away from the orifice 119.
• Each zone 194a and 194b receives a respective control signal 192a and 192b from the controller 190.
• the control signals 192a and 192b have different characteristics.
• each of the control signals 192a and 192b may be a voltage signal that has a different band of frequencies.
• control signal 192a includes a plurality of sine wave voltage signals having frequencies between 50 kiloHertz (kHz) and 1 MegaHertz (MHz), and the control signal 192b includes a plurality of sine wave voltage signals having frequencies between 1 MHz and 20 MHz.
• each control signal 192a and 192b may be a square wave or a triangle wave.
• the control signals 192a and 192b are periodic with the frequency at which the coalesced targets arrive at the plasma formation location 123. That is, the control signals 192a and 192b have a periodicity that is equal to the frequency at which the coalesced targets arrive at the plasma formation location 123.
• each of the control signals 192a and 192b may be an electrical signal having a frequency spectrum that includes only the base frequency (the frequency at which the targets arrive at the location 12) and harmonics of the base frequency.
• the controller 190 may be implemented as more than one separate controller or may control separate function or signal generators. In these implementations, the signals 192a and 192b are synchronized to the same clock to avoid phase drift between the signals 192a and 192b.
• Using two or more controllable zones improves the performance and usability of the supply system 110.
• driving various zones of the actuator 193 with different control signals increases the frequency bandwidth at which the actuator 193 may be driven.
• the actuator 193 is driven with a single control signal with a relatively large frequency bandwidth (for example, 50 kHz to 20 MHz).
• the single control signal may be amplified, however, amplifiers have a finite gain- bandwidth characteristic, with the gain of the amplifier decreasing as the bandwidth of the signal to amplify increases.
• each of the control signals 192a and 192b may be amplified by a separate amplifier. Accordingly, greater amplification of the control signals 192a and 192b is possible.
• the pressure P is increased, the droplets in the stream 121 are spaced farther apart from each other, and the velocity of the jet 124 is increased by increasing the frequency bandwidth at which the actuator 193 is driven.
• a pressure P of 275 bars the bandwidth of the control signals is 50 kHz to 5 MHz.
• the bandwidth of the control signals is 100 kHz to 20 MHz.
• the relatively larger frequency bandwidth for the pressure P of 1400 bar is split between the zones 194a and 194b instead of being applied to the conduit 114 with a single control signal.
• each zone 194a and 194b with the respective control signal 192a and 192b allows the actuator 193 to be driven at a wider range of frequencies efficiently and effectively, and with simpler electronics.
• the zones 194a and 194b may be mechanically coupled, the zones 194a and 194b are spatially distinct. This arrangement allows certain frequency bands to be delivered to particular parts of the actuator 193 and allows greater control over the formation of the stream 122 and also allows the actuator 193 to be used more effectively.
• the zones 194a and 194b are different shapes and/or sizes.
• the actuator 193 may be a ceramic material such as lead zirconate titanate (PZT).
• PZT lead zirconate titanate
• I C*dV/dt
• dV/dt increases with frequency.
• the amount of capacitance of the PZT depends on its thickness and area.
• the actuator 193 may be configured such that the zones 194a and 194b are different sizes to address the challenges presented by the frequency characteristics of the actuator 193 material.
• the zone 194a may be a relatively large PZT
• the zone 194b may be a relatively small PZT.
• the larger zone 194a is driven at a relatively low frequency and generates a large volume fluctuation in the target material that is inside the conduit 114.
• the actuator 193 may be effectively and efficiently driven at a wide range of frequencies. For example, driving the zone 194b at a different frequency than the zone 194a may result in twice the amount of actuation at the frequencies in the control signal 192a (because of the ability to relatively easily amplify a low frequency signal) and 10 times the amount of actuation at the frequencies in the control signal 192b (because of the reduction in capacitance due).
• FIG. 1 The configuration shown in FIG. 1 is an example, and other implementations are possible.
• the conduit 114 may be a capillary tube, such as the capillary tube 214 shown in FIGS. 2, 3, and 4.
• the nozzle housing or mount 117 attaches the capillary tube to the vacuum chamber 109 and fluidly couples the capillary tube to the reservoir 112.
• the conduit 114 extends from the nozzle mount or housing 117 and is not necessarily housed within the mount or housing 117. In the example shown in FIG. 1, the conduit extends substantially along the X direction. However, in some implementations, the conduit 114 has a more complex path and extends in more than one direction. FIG. shows a conduit 514 that has a more complex path.
• FIG. 2A is a side cross-sectional block diagram of a target formation apparatus 216 in an X-Z plane.
• FIG. 2B is a cross-sectional view of the target formation apparatus 216 in a Y-Z plane taken along the line 2B’ — 2B’ of FIG. 2A.
• the target formation apparatus 216 may be used in the EUV light source 100 (FIG. 1).
• the target formation apparatus 216 includes a capillary tube 214.
• the capillary tube 214 includes a sidewall 230 that extends along the X direction from a first end 231 to a second end 232.
• the sidewall 230 is a three-dimensional object that is generally cylindrical.
• the sidewall 230 may be made of, for example, glass or quartz.
• the sidewall 230 includes an inner surface 233 and an outer surface 239.
• the inner surface 233 defines an interior region 238 that is in fluid communication with a nozzle 235 at the first end 231.
• the nozzle 235 narrows along the -X direction to define an orifice 219.
• the interior region 238 is fluidly coupled to a reservoir of target material (such as the reservoir 112 of FIG. 1), and molten target material flows in the interior region 238 and through the orifice 219 in the -X direction.
• the outer surface 239 is mechanically coupled to an actuator assembly 293.
• the outer surface 239 may be mechanically coupled to the actuator assembly 293 with, for example, an adhesive (such as for, example, a benzoxazine resin, a resin containing benzoxazines, a bismaleimide resin, a cyanate ester resin, or a resin containing cyanate esters), with mechanical fasteners, or by direct contact between the outer surface 239 and the actuator assembly 293 (for example, an interference fit).
• an adhesive such as for, example, a benzoxazine resin, a resin containing benzoxazines, a bismaleimide resin, a cyanate ester resin, or a resin containing cyanate esters
• the actuator assembly 293 includes an actuation body 291 and electrodes 295a, 295b, and 295g.
• the actuation body 291 is generally cylindrical and includes an inner wall 285 and an outer surface 286.
• the inner wall 285 defines a bore that surrounds a portion of the outer surface 239 of the capillary tube 214.
• the actuation body 291 is made out of a material that is capable of causing the sidewall 230 to move.
• the actuation body 291 may be a piezoelectric ceramic material such as lead zirconate titanate (PZT) that changes shape in response to the application of voltage.
• PZT lead zirconate titanate
• the motion of the actuation body 291 causes a corresponding displacement of the sidewall 230 of the by radial contraction and expansion.
• the radial contraction and expansion causes acoustic or pressure waves in the interior region 238.
• the actuation body 291 has a first zone 294a, a second zone 294b, and a ground zone 294g.
• the first zone 294a and the second zone 294b are separately controllable zones.
• the first zone 294a is between the second zone 294b and the ground zone 294g.
• the second zone 294b is the zone that is closest to the orifice 219.
• the radial thickness of the first zone 294a, the second zone 294b, and the ground zone 294g is substantially the same.
• the second zone 294b extends for a shorter distance along the X direction than the first zone 294a.
• the second zone 294b has a smaller volume of material (for example, PZT) than the first zone 294a.
• the electrode 295g is on a portion of the outer surface 286 that is adjacent to the ground zone 294g.
• the electrode 295g also runs along an edge 284 of the actuator body 291 and along the inner wall 285.
• the electrode 295g is electrically connected to ground or a reference voltage.
• the electrode 295a is on a portion of the outer surface 296 that is adjacent to the first zone 294a.
• the electrode 295b is on a portion of the outer surface 296 that is adjacent to the second zone 294b.
• the electrodes 295a, 295b, 295g may be coated on the outer surface 296, attached to the outer surface 296 with mechanical fasteners, and/or attached to the outer surface 296 with an electrically conductive adhesive.
• the actuation body 291 includes spatial features 288a and 288b on the outer surface 286.
• the spatial feature 288a provides separation between the electrodes 295g and 295a
• the spatial feature 288b provides separation between the electrodes 295a and 295b.
• the actuation body 291 is a single piece of material or a collection of pieces of material that are joined during use.
• the ground zone 294g, the first zone 294a, and the second zone 294b are mechanically coupled.
• the spatial feature 288a provides partial mechanical decoupling or partial mechanical isolation between the ground zone 294g and the first zone 294a
• the spatial feature 288b provides partial mechanical decoupling or partial mechanical isolation between the first zone 294a and the second zone 294b.
• the spatial features 288a and 288b are recesses formed on the outer surface 286.
• the recesses 288a and 288b have a semi-circular cross-section and surround the outer surface 286.
• the recesses 288a and 288b are recessed rings that encircle the actuation body 291.
• the spatial features 288a and 288b may take any form that provides partial mechanical isolation between adjacent zones.
• the spatial features 288a and 288b may be recesses that have triangular, rectangular, square, or irregular cross-sections instead of semi-circular cross-sections.
• the spatial features 288a and 288b may protrude from the outer surface 296 instead of being recessed into the outer surface 296. Moreover, the spatial features 288a and 299b may extend for less than the entire circumference of the actuation body 291.
• the spatial features 288a and 288b do not have the same dimensions and do not have the same spatial characteristics.
• the controller 190 (FIG. 1) provides the first control signal 192a to the first electrode 295a such that the first zone 294a moves in accordance with the first control signal 192a.
• the first control signal 192a may include sine wave voltage signals having a frequencies between 50 kHz and 1 MHz, and the application of the first control signal 192a causes the first zone 294a to vibrate at these frequencies.
• the controller 190 provides the second control signal 192b to the second electrode 295b such that the second zone 294b moves in accordance with the second control signal 192b.
• the second control signal 192b may include sine wave voltage signals having a frequencies between 1 MHz and 20 MHz, and the application of the second control signal 192b causes the second zone 294b to vibrate at these frequencies.
• the target formation apparatus 216 includes two separately controllable zones (the zones 294a and 294b), and the characteristics of the control signals applied to each zone may be varied such that the motion of the actuator body 291 is more finely controllable.
• the vibrations of the zones 294a and 294b produce corresponding pressure or acoustic waves in the target material in the interior region 238 to encourage droplet formation at the frequency and size appropriate for the application.
• FIG. 3 is a side cross-sectional block diagram of a target formation apparatus 316 in an X-Z plane.
• the target formation apparatus 316 may be used in the EUV light source 100 to generate the stream 122 (FIG. 1).
• the target formation apparatus 316 includes the capillary tube 214 and an actuator assembly 393.
• the actuator assembly 393 includes an actuator body 391 with a ground zone 394g, a first zone 394a, and a second zone 394b.
• the first zone 394a is between the ground zone 394g and the second zone 394b.
• the actuator body 391 includes an outer surface 386 and an inner wall 385.
• the actuator body 391 also includes spatial features 388a and 388b on the outer surface 386.
• the actuator assembly 393 is similar to the actuator assembly 293 except that the spatial features 388a and 388b are not the same size and shape.
• the spatial feature 388a is a recess in the outer surface 386.
• the spatial feature 388a has a semi-circular cross-section and surrounds the actuator body 391.
• the spatial feature 388b is also a recess in the outer surface 386, but the spatial feature 388b extends farther into the outer surface 386 and has a different cross-sectional shape as compared to the spatial feature 388a.
• the spatial feature 388b has an asymmetrical arc-shaped cross- section, with a first side 381a and a second side 381b.
• the first side 381a and the second side 381a are curves or arcs that form the larger arc that defines the spatial feature 388b.
• the first side 381a extends farther from the inner wall 385 than the second side 381b.
• the first zone 394a has a thicker radial dimension than the second zone 394b.
• the second zone 394b has a smaller extent in the X direction and thus has a smaller volume than the first zone 394b.
• the spatial feature 388b extends deeper into the outer surface 386, the first zone 394a and the second zone 394b are connected by a relatively thin portion of the actuator body 291.
• the spatial feature 388b provides more mechanical separation between adjacent zones.
• the spatial feature 388b provides additional mechanical isolation and mechanical separation such that the first zone 394a and the second zone 394b are more mechanically separated than the first zone 294a and the second zone 294b.
• a ground electrode 395g which is on a portion of the outer surface 386 that is adjacent to the ground zone 394g, an edge 384, and the inner wall 385, is electrically connected to ground or a reference potential.
• An electrode 395a is on a portion of the outer surface 386 that is adjacent to the first zone 394a.
• An electrode 395b is on a portion of the outer surface 386 that is adjacent to the second zone 394b.
• the electrodes 395a and 395b receive the control signals 191a and 192b, respectively, from the controller 190 (FIG. 1).
• the relatively small volume of the second zone 394b allows the second zone 394b to be driven at higher frequencies (for example, 1 to 20 MHz) efficiently.
• the actuator assembly 292 and/or 392 may include more than two zones that are separately controllable.
• the actuator body 291 and/or 391 may include three zones, four zones, or more than four zones that are associated with an electrode that receives a control signal from the controller 190.
• the actuator assembly 293 and or 393 may be configured to be controlled with three, four, or more separate frequency bands.
• the actuator assemblies 293 and 393 include respective actuator bodies 291 and 391 that are a single-piece of material. However, in other implementations, the actuator assembly includes a plurality of discrete or distinct actuator bodies. FIGS. 4, 5, and 7 show examples of such actuator assemblies.
• FIG. 4 is a side cross-sectional block diagram of a target formation apparatus 416 in an X-Z plane.
• the target formation apparatus 416 may be used in the EUV light source 100 to generate the stream 122 (FIG. 1).
• the target formation apparatus 416 includes the capillary tube 214 and an actuator assembly 493.
• the actuator assembly 493 includes a ground zone 494g, a first zone 494a, and a second zone 494b.
• the first zone 494a is between the ground zone 494g and the second zone 494b.
• Each of the ground zone 494g, the first zone 494a, and the second zone 494b is a discrete body of actuation material.
• each of these zones may be a ring of PZT material that surrounds and is mechanically coupled to the outer wall 239 of the capillary tube 214.
• the ground zone 494g, the first zone 494a, and the second zone 494b are positioned along the sidewall 230 such that they do not directly touch each other.
• a ground electrode 495g which is on the ground zone 494g and runs along the outer surface 239 of the sidewall 230, is electrically connected to ground or a reference potential.
• An electrode 495a is on the first zone 494a.
• An electrode 495b is on the second zone 494b.
• the electrodes 495a and 495b receive the control signals 191a and 191b, respectively, from the controller 190 (FIG. 1).
• the second zone 494b has a smaller volume than the first zone 494a. The relatively small volume of the second zone 494b allows the second zone 494b to be driven at higher frequencies (for example, 1 to 20 MHz) efficiently.
• the target formation apparatus 416 may be implemented with the ground zone 494g and the first zone 494a on a single piece of material and partially mechanically isolated by a spatial feature such as the spatial feature 388a.
• the second zone 494b is a separate piece of material and does not directly touch the first zone 494a or the ground zone 494g.
• the target formation apparatus 416 is shown with two zones that receive control signals from the controller 190 (the first zone 494a and the second zone 494b), the target formation apparatus 416 may be implemented with additional zones that are configured to receive control signals from the controller 190 (or another controller).
• FIG. 5 is a side cross-sectional block diagram of a target formation apparatus 516 in an X-Z plane.
• the target formation apparatus 516 may be used in the EUV light source 100 to generate the stream 122 (FIG. 1).
• the target formation apparatus 516 includes an actuator assembly 593 and a conduit 514 that are held in a mounting assembly or housing 511.
• the housing 511 holds the actuator assembly 593 and the conduit 514 and may be used to mount the target formation apparatus 516 to a vacuum chamber such as the chamber 109 of FIG. 1.
• the conduit 514 includes an interior region 538 that is configured to fluidly couple to a reservoir such as the reservoir 112 (FIG. 1).
• the interior region 538 may be fluidly coupled to the reservoir by a channel (not shown) that is drilled through the housing 511 or otherwise formed in the housing 511.
• the conduit 514 has a substantially T- shape that includes a region 514a that extends in the Z direction (and may extend in the Y-Z plane) and a region 514b that extends in the X direction.
• the region 514b narrows to an orifice 519 through which target material can pass.
• the region 514a is in fluid contact with a membrane 512.
• the membrane 512 is flexible and moveable, and motion of the membrane 512 creates pressure waves in the interior region 538.
• the membrane 512 may be part of the housing 511, or the membrane 512 may be a separate element that is attached to the housing 511.
• the housing 511 and the membrane 512 may be made of, for example, molybdenum, tantalum, or tungsten.
• the actuator assembly 593 includes a first zone 594a and a second zone 594b.
• the first and second zones 594a 594b are shown with diagonal shading.
• the first zone 594a and the second zone 594b are made of a actuation material such as PZT.
• the first zone 594a and the second zone 594b are discrete zones and do not directly touch each other.
• the first zone 594a and the second zone 594b are three-dimensional objects and may have, for example, a circular, rectangular, or square shape in the Y-Z plane.
• the first and second zones 594a and 594b may be continuous objects and do not necessarily include an opening, bore, or other feature that could be used to positioned the zone 594a or the zone 594b around another object.
• the first and second zones 594a and 594b may have different shapes in the Y-Z plane. In the example shown in FIG. 5, the second zone 594b has a smaller spatial volume than the first zone 594a.
• the actuator assembly 593 includes a positioning mechanism 571, which is configured to position and hold the first zone 594a.
• the positioning mechanism 571 may include, for example, pre tension wedges and/or spacers that hold the first zone 594a in place while also allowing the first zone 594a to change shape.
• the actuator assembly 593 also includes a block 572 that is between the second zone 594b and the first zone 594a.
• the block 572 has a face 572a and a tip 572b.
• the tip 572b extends away from the face 572a in the -X direction and is narrower in the Z direction than the face 572a.
• the face 572a is in contact with the first zone 594a.
• the second zone 594b is mounted on the tip 572b.
• the tip 572b makes contact with the membrane 512.
• the tip 572b is shaped to guide vibrations from the motion of the first zone 594a to the membrane 512.
• control signals 191a and 191b from the controller 190 are provided, respectively, to the first zone 494a and the second zone 494b to control the motion of these zones.
• the vibrations of the first and second zones 594a, 594b are transferred from the tip 572b to the membrane 512.
• the membrane 512 vibrates based on the frequencies at which the first and second zones 594a and 594b vibrate.
• the vibration of the membrane 512 causes corresponding acoustic waves in the interior region 538.
• the actuator assembly 593 may include additional elements.
• the actuator assembly 593 may include one or more electrodes on each zone 594a and 594b.
• the actuator assembly 593 may include more than one controllable zone and thus may include more PZTs than what is shown in FIG. 5.
• FIG. 6 is a side cross-sectional block diagram of an actuator assembly 693, which is an example implementation of the actuator assembly 593 in which the first zone 594a is implemented as a stack of PZT disks 694.
• the stack 694 may include 10, 50, 100, or more thin PZT disks.
• the disks may have a circular cross section in the Y-Z plane.
• the stack 694 may have an extent of about 2 millimeters (mm) to 10 mm in the X direction.
• the stack 694 may be held together by a compressive force along the X direction provided by the positioning mechanism 571.
• FIG. 7 is a side-cross sectional block diagram of a target formation apparatus 716 in an X-Z plane.
• the target formation apparatus 716 may be used in the EUV light source 100 to generate the stream 122 (FIG. 1).
• the target formation apparatus 716 includes a conduit 714 that defines an interior region 738 and an orifice 719.
• the conduit 714 is generally cone shaped and narrows in the - X direction to the orifice 719.
• the target formation apparatus 716 also includes various mounting elements or housings 711.
• the mounting elements or housings 711 are used to house the components of the target formation apparatus 716 and mount the target formation apparatus 516 to a vacuum chamber, such as the vacuum chamber 109.
• the target formation apparatus 716 also includes zones 794a and 794b, each of which is a ring of PZT material that is mounted to an outer surface 733 of the conduit 714.
• the zone 794a has a larger radius and a greater longitudinal thickness than the zone 794b.
• the zone 794b has a smaller spatial volume than the zone 794b.
• the zone 794b is closer to the orifice 719.
• the control signals 191a and 191b from the controller 190 are provided, respectively, to leads 111 and 778.
• the leads 111 and 778 may be electrical wires or cables.
• the lead 111 is electrically connected to an electrode (not shown) on the first zone 794a
• the lead 778 is electrically connected to an electrode (not shown) on the second zone 794b.
• the control signals 191a and 191b control the motion of the zones 794a and 794b, respectively.
• the vibrations of the first and second zones 794a, 794b are transferred to the interior space 738 and create acoustic waves in the interior region 538.
• Any of the target formation apparatuses 216, 316, 416, 516, and 716 discussed above may be used in an EUV light source.
• an implementation of an LPP EUV light source 800 is shown. Any of the nozzle assemblies discussed above may be used in the light source 800 as part of a supply system 825.
• the LPP EUV light source 800 is formed by irradiating a target mixture 814 at a plasma formation location 805 with an amplified light beam 810 that travels along a beam path toward the target mixture 814.
• the target material discussed with respect to FIG. 1, and the targets in the stream 121 discussed with respect to FIG. 1 may be or include the target mixture 814.
• the plasma formation location 805 is within an interior 807 of a vacuum chamber 830.
• a target material within the target mixture 814 is converted into a plasma state that has an element with an emission line in the EUV range.
• the created plasma has certain characteristics that depend on the composition of the target material within the target mixture 814. These characteristics may include the wavelength of the EUV light produced by the plasma and the type and amount of debris released from the plasma.
• the light source 800 also includes the supply system 825 that delivers, controls, and directs the target mixture 814 in the form of liquid droplets, a liquid stream, solid particles or clusters, solid particles contained within liquid droplets or solid particles contained within a liquid stream.
• the target mixture 814 includes the target material such as, for example, water, tin, lithium, xenon, or any material that, when converted to a plasma state, has an emission line in the EUV range.
• the element tin may be used as pure tin (Sn); as a tin compound, for example, SnBr 4 , Snlfe, SnIU; as a tin alloy, for example, tin-gallium alloys, tin-indium alloys, tin-indium-gallium alloys, or any combination of these alloys.
• the target mixture 814 may also include impurities such as non-target particles. Thus, in the situation in which there are no impurities, the target mixture 814 is made up of only the target material.
• the target mixture 814 is delivered by the supply system 825 into the interior 807 of the chamber 830 and to the plasma formation location 805.
• the light source 800 includes a drive laser system 815 that produces the amplified light beam 810 due to a population inversion within the gain medium or mediums of the laser system 815.
• the light source 800 includes a beam delivery system between the laser system 815 and the plasma formation location 805, the beam delivery system including a beam transport system 820 and a focus assembly 822.
• the beam transport system 820 receives the amplified light beam 810 from the laser system 815, and steers and modifies the amplified light beam 810 as needed and outputs the amplified light beam 810 to the focus assembly 822.
• the focus assembly 822 receives the amplified light beam 810 and focuses the beam 810 to the plasma formation location 805.
• the laser system 815 may include one or more optical amplifiers, lasers, and/or lamps for providing one or more main pulses and, in some cases, one or more pre pulses.
• Each optical amplifier includes a gain medium capable of optically amplifying the desired wavelength at a high gain, an excitation source, and internal optics.
• the optical amplifier may or may not have laser mirrors or other feedback devices that form a laser cavity.
• the laser system 815 produces an amplified light beam 810 due to the population inversion in the gain media of the laser amplifiers even if there is no laser cavity.
• the laser system 815 may produce an amplified light beam 810 that is a coherent laser beam if there is a laser cavity to provide enough feedback to the laser system 815.
• the term “amplified light beam” encompasses one or more of: light from the laser system 815 that is merely amplified but not necessarily a coherent laser oscillation and light from the laser system 815 that is amplified and is also a coherent laser oscillation.
• the optical amplifiers in the laser system 815 may include as a gain medium a filling gas that includes CO2 and may amplify light at a wavelength of between about 9100 and about 11000 nm, and in particular, at about 10600 nm, at a gain greater than or equal to 800 times.
• Suitable amplifiers and lasers for use in the laser system 815 may include a pulsed laser device, for example, a pulsed, gas- discharge CO2 laser device producing radiation at about 9300 nm or about 10600 nm, for example, with DC or RF excitation, operating at relatively high power, for example, lOkW or higher and high pulse repetition rate, for example, 40 kHz or more.
• the pulse repetition rate may be, for example, 50 kHz.
• the optical amplifiers in the laser system 815 may also include a cooling system such as water that may be used when operating the laser system 815 at higher powers.
• the light source 800 includes a collector mirror 835 having an aperture 840 to allow the amplified light beam 810 to pass through and reach the plasma formation location 805.
• the collector mirror 835 may be, for example, an ellipsoidal mirror that has a primary focus at the plasma formation location 805 and a secondary focus at an intermediate location 845 (also called an intermediate focus) where the EUV light may be output from the light source 800 and may be input to, for example, an integrated circuit lithography tool (not shown).
• the light source 800 may also include an open-ended, hollow conical shroud 850 (for example, a gas cone) that tapers toward the plasma formation location 805 from the collector mirror 835 to reduce the amount of plasma-generated debris that enters the focus assembly 822 and/or the beam transport system 820 while allowing the amplified light beam 810 to reach the plasma formation location 805.
• a gas flow may be provided in the shroud that is directed toward the plasma formation location 805.
• the light source 800 may also include a master controller 855 that is connected to a droplet position detection feedback system 856, a laser control system 857, and a beam control system 858.
• the light source 800 may include one or more target or droplet imagers 860 that provide an output indicative of the position of a droplet, for example, relative to the plasma formation location 805 and provide this output to the droplet position detection feedback system 856, which may, for example, compute a droplet position and trajectory from which a droplet position error may be computed either on a droplet by droplet basis or on average.
• the droplet position detection feedback system 856 thus provides the droplet position error as an input to the master controller 855.
• the master controller 855 may therefore provide a laser position, direction, and timing correction signal, for example, to the laser control system 857 that may be used, for example, to control the laser timing circuit and/or to the beam control system 858 to control an amplified light beam position and shaping of the beam transport system 820 to change the location and or focal power of the beam focal spot within the chamber 830.
• the supply system 825 includes a target material delivery control system 826 that is operable, in response to a signal from the master controller 855, for example, to modify the release point of the droplets as released by a target material supply apparatus 827 to correct for errors in the droplets arriving at the desired plasma formation location 805.
• the target material supply apparatus 827 may be or include any of the target formation apparatuses and/or any of the actuators discussed above.
• the light source 800 may include light source detectors 865 and 870 that measures one or more EUV light parameters, including but not limited to, pulse energy, energy distribution as a function of wavelength, energy within a particular band of wavelengths, energy outside of a particular band of wavelengths, and angular distribution of EUV intensity and or average power.
• the light source detector 865 generates a feedback signal for use by the master controller 855.
• the feedback signal may be, for example, indicative of the errors in parameters such as the timing and focus of the laser pulses to properly intercept the droplets in the right place and time for effective and efficient EUV light production.
• the light source 800 may also include a guide laser 875 that may be used to align various sections of the light source 800 or to assist in steering the amplified light beam 810 to the plasma formation location 805.
• the light source 800 includes a metrology system 824 that is placed within the focus assembly 822 to sample a portion of light from the guide laser 875 and the amplified light beam 810.
• the metrology system 824 is placed within the beam transport system 820.
• the metrology system 824 may include an optical element that samples or re-directs a subset of the light, such optical element being made out of any material that may withstand the powers of the guide laser beam and the amplified light beam 810.
• a beam analysis system is formed from the metrology system 824 and the master controller 855 since the master controller 855 analyzes the sampled light from the guide laser 875 and uses this information to adjust components within the focus assembly 822 through the beam control system 858.
• the light source 800 produces an amplified light beam 810 that is directed along the beam path to irradiate the target mixture 814 at the plasma formation location 805 to convert the target material within the mixture 814 into plasma that emits light in the EUV range.
• the amplified light beam 810 operates at a particular wavelength (that is also referred to as a drive laser wavelength) that is determined based on the design and properties of the laser system 815.
• the amplified light beam 810 may be a laser beam when the target material provides enough feedback back into the laser system 815 to produce coherent laser light or if the drive laser system 815 includes suitable optical feedback to form a laser cavity.
• a system comprising: a conduit comprising an orifice configured to fluidly couple to a reservoir and to emit molten target material; an actuator comprising at least a first zone and a second zone that is between the first zone and the orifice, wherein motion of the first zone and the second zone is transferred to an interior of the conduit; and a controller configured to apply a first actuation signal to the first zone and a second actuation signal to the second zone, wherein the second actuation signal has a higher frequency than the first actuation signal.
• the actuator comprises a tube comprising: a first end; a second end; an inner wall that extends from the first end to the second end and is mechanically coupled to the exterior of the conduit; the second end is closer to the orifice than the first end; the first zone of the actuator is a first portion of the tube, and the second zone of the actuator is a second portion of the tube; and at least one surface feature is formed on the exterior of the actuator between the first zone and the second zone, wherein each surface feature is configured to provide partial mechanical isolation between the first zone and the second zone.
• the at least one surface features comprises a plurality of grooves; each groove surrounds the tube; and each groove has a groove shape.
• each actuator electrode surrounds the associated zone.
• each of the first actuation signal and the second actuation signal comprise at least one sine wave.
• a method comprising: fluidly coupling an orifice of a conduit to a reservoir that holds molten target material; applying pressure to the reservoir such that the molten target material flows in the conduit; applying a first actuation signal to a first zone of an actuator that is mechanically coupled to the conduit, the first actuation signal having a first frequency spectrum; and applying a second actuation signal to a second zone of the actuator, wherein the second actuation signal has a second frequency spectrum, and the second frequency spectrum comprises higher frequencies than the first frequency spectrum.
• a system comprising: a conduit comprising an orifice configured to fluidly couple to a reservoir and to emit molten target material; a single-piece actuator mechanically coupled to the conduit, the single-piece actuator comprising a plurality of separately controllable zones; and a controller configured to apply a separate actuation signal to each of at least a first zone and a second zone.
• a system comprising: a conduit comprising an orifice configured to fluidly couple to a reservoir and to emit molten target material; an actuator mechanically coupled to the conduit, the actuator comprising a plurality of separately controllable zones, wherein the plurality of separately controllable zones comprises at least a first zone and a second zone, the second zone is between the first zone and the orifice; and the second zone is smaller than the first zone; and a controller configured to apply a first actuation signal to the first zone and a second actuation signal to the second zone.
• An actuator comprising: an actuator body comprising: a ground zone configured to be electrically connected to a reference potential; and a plurality of controllable zones, wherein each controllable zone is configured to receive a control signal, and wherein, in operational use, the controllable zones are configured to be mechanically coupled to a conduit such that the motion of the controllable zones generates pressure waves in an interior region of the conduit.
• the actuator body comprises a single piece of material; the ground zone and the plurality of controllable zones are part of the single piece of material; and the single piece of material comprises a plurality of spatial features; and the ground zone is separated from the plurality of controllable zones by one of the plurality of spatial features, and each controllable zone is separated from a nearest controllable zone by one of the plurality of spatial features.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Optics & Photonics (AREA)
• Plasma & Fusion (AREA)
• Injection Moulding Of Plastics Or The Like (AREA)
• Powder Metallurgy (AREA)
• Continuous Casting (AREA)
• Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)

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• 2022
  • 2022-05-19 TW TW111118622A patent/TW202315462A/zh unknown
  • 2022-05-26 WO PCT/EP2022/064365 patent/WO2022258391A2/en active Application Filing
  • 2022-05-26 IL IL309052A patent/IL309052A/en unknown
  • 2022-05-26 CN CN202280041058.3A patent/CN117480868A/zh active Pending

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