WO2022225647A1 - Formation de multiples images aériennes en un seul passage d'exposition lithographique - Google Patents

Formation de multiples images aériennes en un seul passage d'exposition lithographique Download PDF

Info

Publication number
WO2022225647A1
WO2022225647A1 PCT/US2022/022022 US2022022022W WO2022225647A1 WO 2022225647 A1 WO2022225647 A1 WO 2022225647A1 US 2022022022 W US2022022022 W US 2022022022W WO 2022225647 A1 WO2022225647 A1 WO 2022225647A1
Authority
WO
WIPO (PCT)
Prior art keywords
energy
pulse
light
light beam
pulses
Prior art date
Application number
PCT/US2022/022022
Other languages
English (en)
Inventor
Yingbo Zhao
Joshua Jon THORNES
Original Assignee
Cymer, Llc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cymer, Llc filed Critical Cymer, Llc
Priority to CN202280038621.1A priority Critical patent/CN117441133A/zh
Priority to JP2023560973A priority patent/JP2024518258A/ja
Publication of WO2022225647A1 publication Critical patent/WO2022225647A1/fr

Links

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
    • G03F7/7055—Exposure light control in all parts of the microlithographic apparatus, e.g. pulse length control or light interruption
    • G03F7/70558—Dose control, i.e. achievement of a desired dose
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70008—Production of exposure light, i.e. light sources
    • G03F7/70041—Production of exposure light, i.e. light sources by pulsed sources, e.g. multiplexing, pulse duration, interval control or intensity control
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70008—Production of exposure light, i.e. light sources
    • G03F7/7005—Production of exposure light, i.e. light sources by multiple sources, e.g. light-emitting diodes [LED] or light source arrays

Definitions

  • This disclosure relates to forming multiple aerial images in a single lithography exposure pass.
  • the techniques discussed below can be used, for example, to form a three-dimensional semiconductor component.
  • Photolithography is the process by which semiconductor circuitry is patterned on a substrate such as a silicon wafer.
  • a photolithography optical source provides the deep ultraviolet (DUV) light used to expose a photoresist on the wafer.
  • DUV light for photolithography is generated by excimer optical sources.
  • the optical source is a laser source and the pulsed light beam is a pulsed laser beam.
  • the light beam is passed through a beam delivery unit, a reticle or a mask, and then projected onto a prepared silicon wafer. In this way, a chip design is patterned onto a photoresist that is then etched and cleaned, and then the process repeats.
  • a method for controlling an energy of a pulsed light beam includes: producing a plurality of intermingled sets of pulses of the light beam from an optical source, each set of light beam pulses associated with a distinct primary wavelength and a distinct target energy; receiving a measurement of an energy of a prior pulse of the light beam; determining an energy error including: comparing the measured energy of the prior light beam pulse to a particular target energy associated with a particular set of light beam pulses if the prior light beam pulse is in the particular set of light beam pulses; and adjusting at least one component of the optical source to thereby adjust, based on the determined energy error, the energy of a subsequent pulse in the particular set of light beam pulses.
  • Implementations can include one or more of the following features.
  • the method can include receiving each distinct target energy associated with each set of light beam pulses.
  • the method can include categorizing whether the prior light beam pulse is in the particular set of light beam pulses.
  • the method can include determining the amount of adjustment to the at least one component of the optical source.
  • the method can include correcting the amount of adjustment to the at least one component of the optical source based on whether the prior light beam pulse is in the particular set of light beam pulses.
  • At least one component of the optical source can be adjusted by changing a voltage provided to electrodes associated with an optical oscillator of the optical source.
  • a system includes: and optical source apparatus and an energy control apparatus communicating with the optical source apparatus.
  • the optical source apparatus includes: an optical oscillator configured to produce a pulse of light in response to an excitation signal, the pulse of light having a spectral property; and a spectral adjustment apparatus configured to control the spectral property of the pulse of light.
  • the energy control apparatus is configured to: determine a target energy associated with the spectral property of the produced pulse of light; and determine, based at least on the determined target energy, an adjustment to the excitation signal that causes the optical oscillator to produce one or more subsequent pulses of light to account for a change in a configuration of the spectral adjustment apparatus.
  • Implementations can include one or more of the following features.
  • the adjustment to the excitation signal can cause an adjustment to the energy of the one or more subsequently produced pulses of light.
  • the target energy associated with the spectral property of the produced pulse of light can be previously defined as being associated with the spectral property of the produced pulse of light.
  • the optical oscillator can be associated with a plurality of transfer functions, each transfer function being associated with a particular configuration of the spectral adjustment apparatus and a particular value of the spectral property.
  • the energy control apparatus can be configured to determine the adjustment to the excitation signal based on the transfer function associated with the particular configuration of the spectral adjustment apparatus used to produce the one or more subsequent pulses of light.
  • the spectral adjustment apparatus can include at least one prism and a diffractive element arranged in optical communication with each other, and each transfer function is associated with a different state of at least one prism.
  • the spectral property of a pulse of light can be a center wavelength of that pulse of light and each configuration of the spectral adjustment apparatus can correspond to a particular value of the wavelength.
  • the system can further include a measurement apparatus configured to measure an energy of the pulse of light.
  • the energy control apparatus can be configured to determine an energy error by comparing the target energy and the measured energy, and the determination of the adjustment to the excitation signal can be also based on the energy error.
  • the energy control apparatus can be configured to determine the adjustment to the excitation signal that causes the optical oscillator to produce the one or more subsequent pulses of light by determining the adjustment to the excitation signal that causes the optical oscillator to produce one or more subsequent pulses of light associated with the spectral property of the produced pulse of light.
  • the energy control apparatus can be configured to determine the target energy associated with the spectral property of the produced pulse of light by receiving a communication from a lithography exposure apparatus that is configured to receive the light pulse, the communication providing a set of target energies, each target energy in the set being associated with a spectral property.
  • an energy control apparatus includes a control module.
  • the control module is configured to receive an energy value of a prior light pulse emitted from an optical source.
  • the control module is configured to perform a comparison that includes comparing the received energy value with a first target energy only if the prior light pulse is in a first set of light beam pulses associated with a first primary wavelength; or comparing the received energy value with a second target energy that is distinct from the first target energy only if the prior light pulse is in a second set of light beam pulses associated with a second primary wavelength that is distinct from the first primary wavelength.
  • the control module is configured to adjust, based on the comparison, at least one component of the optical source to thereby adjust the energy of a subsequent light pulse having the primary wavelength associated with the prior light pulse.
  • the control module can include a category module configured to categorize whether the prior light pulse is in the first set of light beam pulses or in the second set of light beam pulses.
  • the control module can include a comparator configured to determine whether the prior light pulse is in the first set of light beam pulses or the second set of light beam pulses, and to provide the first target energy or the second target energy based on the determination.
  • the control module can include a signal module configured to determine the amount of adjustment to be made to the at least one component of the optical source.
  • the control module can include a correction module configured to correct the amount of adjustment to be made to the at least one component of the optical source based on whether the prior light pulse is in the first or the second set of light beam pulses.
  • the correction module can be configured to correct the adjustment amount by applying a filter to the adjustment amount.
  • the filter can include a notch filter that transmits information having a frequency in a first frequency band and substantially blocks information having a frequency outside the first frequency band.
  • the filter can include a Kalman filter.
  • the correction module can be configured to correct the adjustment amount by applying a feed forward correction to the adjustment amount.
  • the control module being configured to adjust, based on the comparison, at least one component of the optical source to thereby adjust the energy of the subsequent light pulse having the primary wavelength associated with the prior light pulse can include sending a signal to the optical source to thereby change a voltage provided to electrodes associated with an optical oscillator of the optical source.
  • the control module being configured to receive the energy value of the prior light pulses can include the control module being configured to receive the energy value of a plurality of prior light pulses emitted from the optical source.
  • the control module can be configured to adjust, based on the comparison, the at least one component of the optical source to thereby adjust the energy of a plurality of subsequent light pulses having the primary wavelength associated with the prior light pulse.
  • the control module can be configured to maintain, based on the comparison, the energy of a subsequent light pulse that does not have the primary wavelength associated with the prior light pulse.
  • Fig. 1 A is a block diagram of an example of an implementation of a photolithography system.
  • Fig. IB is a block diagram of an example of an implementation of an optical system for the photolithography system of Fig. 1A.
  • Fig. 1C is a cross-sectional view of an example of a wafer exposed by the photolithography system of Fig. 1A.
  • Fig. 2 A is a block diagram of another example of an implementation of a photolithography system.
  • Fig. 2B is a block diagram of an example of an implementation of a spectral feature selection module that can be used in a photolithography system.
  • Fig. 2C is a block diagram of an example of an implementation of a line narrowing module.
  • Figs. 3A, 3B, and 3C are plots of data that relate to the production of pulses and/or bursts of pulses in an optical source.
  • Fig. 4 is a block diagram of another example of an implementation of a photolithography system.
  • Fig. 5 is a flow chart of an example of a process for forming a three-dimensional semiconductor component.
  • Figs. 6A and 6B each show an example of an optical spectrum of a single pulse of light.
  • Fig. 7 shows an example of an average optical spectrum for a single exposure pass.
  • Figs. 8A and 8B show side and top cross-sectional views, respectively, of an example of a wafer.
  • Figs. 9A and 9B show side and top cross-sectional views, respectively, of an example of a three-dimensional semiconductor component.
  • Figs. 10A and 10B show examples of simulated data.
  • Fig. 11 A is a block diagram of a photolithography system in which the control system includes an energy control module configured to provide an excitation signal to the optical source, the excitation signal being used to control electrodes within an optical oscillator of the optical source.
  • Fig. 1 IB is an illustration of examples of the transfer function TF (the optical energy produced by the single optical oscillator as a function of provided excitation energy) of the optical oscillator showing how the optical energy varies with the wavelength of the emitted pulsed light beam.
  • Fig. 12 is a block diagram of an implementation of the energy control module of Fig. 11 A used with an optical oscillator.
  • Fig. 13 is a block diagram of an implementation of the master oscillator that can constitute the optical oscillator.
  • Fig. 14 is a table showing the correlation between each target energy with each possible primary wavelength of the light beam output from the optical source that includes the optical oscillator.
  • Fig. 15A is a graph of a set of target energies for each of four primary wavelengths of the light beam output from the optical source that includes the optical oscillator.
  • Fig. 15B is a cross-sectional view of an example of a wafer exposed in the photolithography system of Fig. 11, in which the light beam output from the optical source that includes the optical oscillator is produced at the four primary wavelengths provided Fig. 15 A.
  • Fig. 16 is a block diagram of an implementation of the energy control module of Fig. 11 A used with an optical oscillator, and including a plurality of energy controllers, each associated with a primary wavelength of the light beam output from the optical source that includes the optical oscillator.
  • Fig. 17 is a block diagram showing an implementation of an energy controller that can be used in the energy control modules of any one or more of Figs. 11, 12, and 16.
  • Fig. 18 is a block diagram showing an implementation of an energy controller that can be used in the energy control modules of any one or more of Figs. 11, 12, and 16.
  • Fig. 19A is a block diagram of an implementation of the energy control module of Fig. 11 A used with an optical oscillator, and including a feed forward energy controller.
  • Fig. 19B is a block diagram of an implementation of the feed forward energy controller of Fig. 19 A.
  • Fig. 19C is a block diagram of an implementation of an excitation determination module of the feed forward energy controller of Fig. 19B.
  • Fig. 20 is a block diagram of an implementation of the energy control module of Fig. 11 A used with an optical oscillator, and including a repetitive control energy controller.
  • Fig. 21 is a flow chart of a procedure performed by the photolithography system of Fig. 11 A.
  • a photolithography system 100 includes an optical (or light) source 105 that provides a light beam 160 to a lithography exposure apparatus 169, which processes a wafer 170 received by a wafer holder or stage 171.
  • the light beam 160 is a pulsed light beam that includes pulses of light separated from each other in time.
  • the lithography exposure apparatus 169 includes a projection optical system 175 through which the light beam 160 passes prior to reaching the wafer 170, and a metrology system 172.
  • the metrology system 172 can include, for example, a camera or other device that is able to capture an image of the wafer 170 and/or the light beam 160 at the wafer 170, or an optical detector that is able to capture data that describes characteristics of the light beam 160, such as intensity of the light beam 160 at the wafer 170 in the x-y plane.
  • the lithography exposure apparatus 169 can be a liquid immersion system or a dry system.
  • the photolithography system 100 also can include a control system 150 to control the light source 105 and/or the lithography exposure apparatus 169.
  • Microelectronic features are formed on the wafer 170 by, for example, exposing a layer of radiation-sensitive photoresist material on the wafer 170 with the light beam 160.
  • the projection optical system 175 includes a slit 176, a mask 174, and a projection objective, which includes a lens 177.
  • the light beam 160 enters the optical system 175 and impinges on the slit
  • the slit 176 is rectangular and shapes the light beam 160 into an elongated rectangular shaped light beam.
  • a pattern is formed on the mask 174, and the pattern determines which portions of the shaped light beam are transmitted by the mask 174 and which are blocked by the mask 174.
  • the design of the pattern is determined by the specific microelectronic circuit design that is to be formed on the wafer 170.
  • the shaped light beam interacts with the mask 174.
  • the portions of the shaped light beam that are transmitted by the mask 174 pass through (and can be focused by) the projection lens 177 and expose the wafer 170.
  • the portions of the shaped light beam that are transmitted by the mask 174 form an aerial image in the x-y plane in the wafer 170.
  • the aerial image is the intensity pattern formed by the light that reaches the wafer 170 after interacting with the mask 174.
  • the aerial image is at the wafer 170 and extends generally in the x-y plane.
  • the system 100 is able to form a plurality of aerial images during a single exposure pass, with each of the aerial images being at a spatially distinct location along the z axis in the wafer 170.
  • the projection optical system 175 forms two aerial images 173a, 173b at different planes along the z axis in a single exposure pass.
  • each of the aerial images 173a, 173b is formed from light having a different primary wavelength.
  • the location of the aerial image along the z axis depends on the characteristics of the optical system 175 (including the projection lens 177 and the mask 174) and the wavelength of the light beam 160.
  • the focal position of the lens 177 depends on the wavelength of the light incident on the lens
  • varying or otherwise controlling the wavelength of the light beam 160 allows the position of the aerial image to be controlled.
  • a plurality (two or more) of aerial images which are each at a different location along the z axis, can be formed in a single exposure pass without moving the optical system 175 (or any components of the optical system 175) and the wafer 170 relative to each other along the z axis.
  • Fig. 1A light passing through the mask 174 is focused to a focal plane by the projection lens 177.
  • the focal plane of the projection lens 177 is between the projection lens 177 and the wafer stage 171, with the position of the focal plane along the z axis depending on the properties of the optical system 175 and the wavelength of the light beam 160.
  • the aerial images 173a, 173b are formed from light having different wavelengths, thus the aerial images 173a, 173b are at different locations in the wafer 170.
  • the aerial images 173a, 173b are separated from each other along the z axis by a separation distance 179.
  • the separation distance 179 depends on the difference between the wavelength of the light that forms the aerial image 173a and the wavelength of the light that forms the aerial image 173b.
  • the wafer stage 171 and the mask 174 (or other parts of the optical system 175) generally move relative to each other in the x, y, and z directions during scanning for routine performance corrections and operation, for example, the motion can be used to accomplish basic leveling, compensation of lens distortions, and for compensation of stage positioning error.
  • This relative motion is referred to as incidental operational motion.
  • the relative motion of the wafer stage 171 and the optical system 175 is not relied upon to form the separation distance 179. Instead, the separation distance 179 is formed due to the ability to control the primary wavelengths in the pulses that pass through the mask 174 during the exposure pass.
  • the separation distance 179 is not created only by moving the optical system 175 and the wafer 170 relative to each other along the z direction.
  • the aerial images 173a and 173b are both present at the wafer 170 during the same exposure pass.
  • the system 100 does not require that the aerial image 173a be formed in a first exposure pass and the aerial image 173b be formed in a second, subsequent exposure pass.
  • the light in the first aerial image 173a interacts with the wafer at a portion 178a, and the light in the second aerial image 173b interacts with the wafer at a portion 178b. These interactions can form electronic features or other physical characteristics, such as openings or holes, on the wafer 170. Because the aerial images 173a, 173b are at different planes along the z axis, the aerial images 173a, 173b can be used to form three-dimensional features on the wafer 170. For example, the aerial image 173a can be used to form a periphery region, and the aerial image 173b can be used to form a channel, trench, or recess that is at a different location along the z axis. As such, the techniques discussed herein can be used to form a three-dimensional semiconductor component, such as a three- dimensional NAND flash memory component.
  • FIG. 2A a block diagram of a photolithography system 200 is shown.
  • the system 200 is an example of an implementation of the system 100 (Fig. 1A).
  • an optical source 205 is used as the optical source 105 (Fig. 1 A).
  • the optical source 205 produces a pulsed light beam 260, which is provided to the lithography exposure apparatus 169.
  • the optical source 205 can be, for example, an excimer optical source that outputs the pulsed light beam 260 (which can be a laser beam). As the pulsed light beam 260 enters the lithography exposure apparatus 169, it is directed through the projection optical system 175 and projected onto the wafer 170. In this way, one or more microelectronic features are patterned onto a photoresist on the wafer 170 that is then developed and cleaned prior to subsequent process steps, and the process repeats.
  • the photolithography system 200 also includes the control system 250, which, in the example of Fig. 2 A, is connected to components of the optical source 205 as well as to the lithography exposure apparatus 169 to control various operations of the system 200.
  • the control system 250 is an example of an implementation of the control system 250 of Fig. 1 A.
  • the optical source 205 is a two-stage laser system that includes a master oscillator (MO) 212 that provides a seed light beam 224 to a power amplifier (PA) 230.
  • the MO 212 and the PA 230 can be considered to be subsystems of the optical source 205 or systems that are part of the optical source 205.
  • the power amplifier 230 receives the seed light beam 224 from the master oscillator 212 and amplifies the seed light beam 224 to generate the light beam 260 for use in the lithography exposure apparatus 169.
  • the master oscillator 212 can emit a pulsed seed light beam, with seed pulse energies of approximately 1 milliJoule (mJ) per pulse, and these seed pulses can be amplified by the power amplifier 230 to about 10 to 15 mJ.
  • mJ milliJoule
  • the master oscillator 212 includes a discharge chamber 214 housing two elongated electrodes 217, a gain medium 219 that is a gas mixture, and a fan for circulating gas between the electrodes 217.
  • a resonator is formed between a line narrowing module 216 on one side of the discharge chamber 214 and an output coupler 218 on a second side of the discharge chamber 214.
  • the line narrowing module 216 can include a diffractive optic such as a grating that finely tunes the spectral output of the discharge chamber 214.
  • Figs. 2B and 2C provide additional detail about the line narrowing module 216.
  • Fig. 2B is a block diagram of an example of an implementation of a spectral feature selection module 258 that includes one or more instances of the line narrowing module 216.
  • the spectral feature selection module 258 couples to light that propagates in the optical source 205.
  • the spectral feature selection module 258 receives the light from the chamber 214 of the master oscillator 212 to enable the fine tuning of the spectral features such as wavelength and bandwidth within the master oscillator 212.
  • the spectral feature selection module 258 can include a control module such as a spectral feature control module 254 that includes electronics in the form of any combination of firmware and software.
  • the control module 254 is connected to one or more actuation systems such as spectral feature actuation systems 255_1 to 255_n.
  • Each of the actuation systems 255_1 to 255_n can include one or more actuators that are connected to respective optical features 256_1 to 256_n of an optical system 257.
  • the optical features 256_1 to 256_n are configured to adjust particular characteristics of the generated light beam 260 to thereby adjust the spectral feature of the light beam 260.
  • the control module 254 receives a control signal from the control system 250, the control signal including specific commands to operate or control one or more of the actuation systems 255_1 to 255_n.
  • the actuation systems 255_1 to 255_n can be selected and designed to work together, that is, in tandem, or the actuation system 255_1 to 255_n can be configured to work individually.
  • each actuation system 255_1 to 255_n can be optimized to respond to a particular class of disturbances.
  • Each optical feature 256_1 to 256_n is optically coupled to the light beam 260 produced by the optical source 105.
  • the optical system 257 can be implemented as a line narrowing module 216C such as that shown in Fig. 2C.
  • the line narrowing module includes as the optical features 256_1 to 256_n dispersive optical elements such as a reflective grating 291 and refractive optical elements such as prisms 292, 293, 294, 295.
  • a reflective grating 291 and refractive optical elements such as prisms 292, 293, 294, 295.
  • One or more of the prisms 292, 293, 294, 295 can be rotatable.
  • An example of this line narrowing module can be found in U.S. Application No. 12/605,306, titled SYSTEM METHOD AN APPARATUS FOR SELECTING AND CONTROLLING LIGHT SOURCE BANDWIDTH, filed on October 23, 2009 (the ‘306 application) and granted as US Patent 8,144,739 on March 27, 2012, the contents of which are hereby incorporated by reference as if set forth in their entirety.
  • a line narrowing module includes a beam expander (including the one or more prisms 292, 293, 294, 295) and the dispersive element such as the grating 291.
  • the respective actuation systems for the actuatable optical features such as the grating 291, and one or more of the prisms 292, 293, 294, 295 are not shown in Fig. 2C.
  • Each of the actuators of the actuation systems 255_1 to 255_n is a mechanical device for moving or controlling the respective optical features 256_1 to 256_n of the optical system 257.
  • the actuators receive energy from the module 254, and convert that energy into some kind of motion imparted to the optical features 256_1 to 256_n of the optical system 257.
  • actuation systems are described such as force devices (to apply forces to regions of the grating) and rotation stages for rotating one or more of the prisms of the beam expander.
  • the actuation systems 255_1 to 255_n can include, for example, motors such as stepper motors, valves, pressure-controlled devices, piezoelectric devices, linear motors, hydraulic actuators, and/or voice coils.
  • the master oscillator 212 also includes a line center analysis module 220 that receives an output light beam from the output coupler 218 and a beam coupling optical system 222 that modifies the size or shape of the output light beam as needed to form the seed light beam 224.
  • the line center analysis module 220 is a measurement system that can be used to measure or monitor the wavelength of the seed light beam 224.
  • the line center analysis module 220 can be placed at other locations in the optical source 205, or it can be placed at the output of the optical source 205.
  • the gas mixture used in the discharge chamber 214 can be any gas suitable for producing a light beam at the wavelength and bandwidth required for the application.
  • the gas mixture can contain a noble gas (rare gas) such as, for example, argon or krypton, a halogen, such as, for example, fluorine or chlorine and traces of xenon apart from helium and/or neon as buffer gas.
  • a noble gas such as, for example, argon or krypton
  • a halogen such as, for example, fluorine or chlorine and traces of xenon apart from helium and/or neon
  • Specific examples of the gas mixture include argon fluoride (ArF), which emits light at a wavelength of about 193 nm, krypton fluoride (KrF), which emits light at a wavelength of about 248 nm, or xenon chloride (XeCl), which emits light at a wavelength of about 351 nm.
  • the excimer gain medium (the gas mixture) is pumped with short (for example, nanosecond) current pulses in a high-voltage electric discharge by application of
  • the power amplifier 230 includes a beam coupling optical system 232 that receives the seed light beam 224 from the master oscillator 212 and directs the light beam through a discharge chamber 240, and to a beam turning optical element 248, which modifies or changes the direction of the seed light beam 224 so that it is sent back into the discharge chamber 240.
  • the discharge chamber 240 includes a pair of elongated electrodes 241, a gain medium 219 that is a gas mixture, and a fan for circulating the gas mixture between the electrodes 241.
  • the output light beam 260 is directed through a bandwidth analysis module 262, where various parameters (such as the bandwidth or the wavelength) of the beam 260 can be measured.
  • the output light beam 260 can also be directed through a beam preparation system 263.
  • the beam preparation system 263 can include, for example, a pulse stretcher, where each of the pulses of the output light beam 260 is stretched in time, for example, in an optical delay unit, to adjust for performance properties of the light beam that impinges the lithography exposure apparatus 169.
  • the beam preparation system 263 also can include other components that are able to act upon the beam 260 such as, for example, reflective and or refractive optical elements (such as, for example, lenses and mirrors), filters, and optical apertures (including automated shutters).
  • the photolithography system 200 also includes the control system 250.
  • the control system 250 is connected to various components of the optical source 205.
  • the control system 250 can control when the optical source 205 emits a pulse of light or a burst of light pulses that includes one or more pulses of light by sending one or more signals to the optical source 205.
  • the control system 250 is also connected to the lithography exposure apparatus 169.
  • the control system 250 also can control the various aspects of the lithography exposure apparatus 169.
  • the control system 250 can control the exposure of the wafer 170 and thus can be used to control how electronic features are printed on the wafer 170.
  • control system 250 can control the scanning of the wafer 170 by controlling the motion of the slit 176 in the x-y plane (Fig. IB). Moreover, the control system 250 can exchange data with the metrology system 172 and/or the optical system 175.
  • the lithography exposure apparatus 169 also can include, for example, temperature control devices (such as air conditioning devices and/or heating devices), and/or power supplies for the various electrical components.
  • the control system 250 also can control these components.
  • the control system 250 is implemented to include more than one sub-control system, with at least one sub-control system (a lithography controller) dedicated to controlling aspects of the lithography exposure apparatus 169.
  • the control system 250 can be used to control aspects of the lithography exposure apparatus 169 instead of, or in addition to, using the lithography controller.
  • the control system 250 includes an electronic processor 251, an electronic storage 252, and an I/O interface 253.
  • the electronic processor 251 includes one or more processors suitable for the execution of a computer program such as a general or special purpose microprocessor, and any one or more processors of any kind of digital computer.
  • a computer program such as a general or special purpose microprocessor, and any one or more processors of any kind of digital computer.
  • an electronic processor receives instructions and data from a read-only memory, a random access memory, or both.
  • the electronic processor 251 can be any type of electronic processor.
  • the electronic storage 252 can be volatile memory, such as RAM, or non-volatile memory. In some implementations, and the electronic storage 252 includes non-volatile and volatile portions or components.
  • the electronic storage 252 can store data and information that is used in the operation of the control system 250, components of the control system 250, and/or systems controlled by the control system 250. The information can be stored in, for example, a look-up table or a database.
  • the electronic storage 252 can store data that indicates values of various properties of the beam 260 under different operating conditions and performance scenarios.
  • the electronic storage 252 can store various recipes or process programs 259 that dictate parameters of the light beam 260 during use.
  • the electronic storage 252 can store a recipe that indicates the wavelength of each pulse in the light beam 260 for a particular exposure pass.
  • the recipe may indicate different wavelengths for different exposure passes.
  • the wavelength controlling techniques discussed below can be applied on a pulse -by-pulse basis. In other words, the wavelength content can be controlled for each individual pulse in an exposure pass to facilitate formation of the aerial images at the desired locations along the z axis.
  • the electronic storage 252 also can store instructions, perhaps as a computer program, that, when executed, cause the processor 251 to communicate with components in the control system 250, the optical system 205, and or the lithography exposure apparatus 169.
  • the I/O interface 253 is any kind of electronic interface that allows the control system 250 to receive and/or provide data and signals with an operator, the optical system 205, the lithography exposure apparatus 169, any component or system within the optical system 205 and/or the lithography exposure apparatus 169, and/or an automated process running on another electronic device.
  • the I/O interface 253 can include one or more of a visual display, a keyboard, and a communications interface.
  • the light beam 260 (and the light beam 160) are pulsed light beams and can include one or more bursts of pulses that are separated from each other in time. Each burst can include one or more pulses of light. In some implementations, a burst includes hundreds of pulses, for example, 100-400 pulses.
  • Figs. 3A-3C provides an overview of the production of pulses and bursts in the optical source 205.
  • Fig. 3A shows an amplitude of a wafer exposure signal 300 as a function of time
  • Fig. 3B shows an amplitude of a gate signal 315 as a function of time
  • Fig. 3C shows an amplitude of a trigger signal as a function of time.
  • the control system 250 can be configured to send the wafer exposure signal 300 to the optical source 205 to control the optical source 205 to produce the light beam 260.
  • the wafer exposure signal 300 has a high value 305 (for example, 1) for a period of time 307 during which the optical source 205 produces bursts of pulses of light.
  • the wafer exposure signal 300 otherwise has a low value 310 (for example, 0) when the wafer 170 is not being exposed.
  • the light beam 260 is a pulsed light beam, and the light beam 260 includes bursts of pulses.
  • the control system 250 also controls the duration and frequency of the bursts of pulses by sending a gate signal 315 to the optical source 205.
  • the gate signal 315 has a high value 320 (for example, 1) during a burst of pulses and a low value 325 (for example, 0) during the time between successive bursts.
  • the duration of time at which the gate signal 315 has the high value is also the duration of a burst 316.
  • the bursts are separated in time by an inter burst time interval. During the inter-burst time interval, the lithography exposure apparatus 169 can position the next die on the wafer 170 for exposure.
  • the control system 250 also controls the repetition rate of the pulses within each burst with a trigger signal 330.
  • the trigger signal 330 includes triggers 340, one of which is provided to the optical source 205 to cause the optical source 205 to produce a pulse of light.
  • the control system 250 can send a trigger 340 to the source 205 each time a pulse is to be produced.
  • the repetition rate of the pulses produced by the optical source 205 (the time between two successive pulses) can be set by the trigger signal 330.
  • the gain medium 219 when the gain medium 219 is pumped by applying voltage to the electrodes 217, the gain medium 219 emits light.
  • the light emitted from the medium 219 is also pulsed.
  • the repetition rate of the pulsed light beam 260 is determined by the rate at which voltage is applied to the electrodes 217, with each application of voltage producing a pulse of light.
  • the pulse of light propagates through the gain medium 219 and exits the chamber 214 through the output coupler 218.
  • a train of pulses is created by periodic, repeated application of voltage to the electrodes 217.
  • the trigger signal 330 can be used to control the application of voltage to the electrodes 217 and the repetition rate of the pulses, which can range between about 500 and 6,000 Hz for most applications. In some implementations, the repetition rate can be greater than 6,000 Hz, and can be, for example, 12,000 Hz or greater.
  • the signals from the control system 250 can also be used to control the electrodes 217, 241 within the master oscillator 212 and the power amplifier 230, respectively, for controlling the respective pulse energies of the master oscillator 212 and the power amplifier 230, and thus, the energy of the light beam 260.
  • the pulsed light beam 260 can have an average output power in the range of tens of watts, for example, from about 50 W to about 130 W.
  • the irradiance (that is, the average power per unit area) of the light beam 260 at the output can range from 60 W/cm 2 to 90 W/cm 2 .
  • the wafer 170 is irradiated by the light beam 260.
  • the lithography exposure apparatus 169 includes the optical system 175 (Figs. 1A and IB).
  • the optical system 175 (not shown) includes an illuminator system 429, which includes an objective arrangement 432.
  • the objective arrangement 432 includes the projection lens 177 (Fig. IB) and enables the image transfer to occur from the mask 174 to the photoresist on the wafer 170.
  • the illuminator system 429 adjusts the range of angles for the light beam 260 impinging on the mask 174.
  • the illuminator system 429 also can homogenize (make uniform) the intensity distribution of the light beam 260 in the x-y plane across the mask 174.
  • an immersion medium can be supplied to cover the wafer 170.
  • the immersion medium can be a liquid (such as water) for liquid immersion lithography.
  • the immersion medium can be a gas such as dry nitrogen, dry air, or clean air.
  • the wafer 170 can be exposed within a pressure-controlled environment (such as a vacuum or partial vacuum).
  • a plurality of N pulses of the light beam 260 illuminates the same area of the wafer 170.
  • N can be any integer number greater than one.
  • the number of pulses N of the light beam 110 that illuminate the same area may be referred to as an exposure window or exposure pass 400.
  • the size of the window 400 can be controlled by the slit 176.
  • the slit 176 can include a plurality of blades that are movable such that the blades form an aperture in one configuration and close the aperture in another configuration. By arranging the blades of the slit 176 to form an aperture of a particular size, the size of the window 400 also can be controlled.
  • the N pulses also determine an illumination dose for the exposure pass.
  • the illumination dose is the amount of optical energy that is delivered to the wafer during the exposure pass.
  • properties of the N pulses such as the optical energy in each pulse, determine the illumination dose.
  • the N pulses also can be used to determine the amount of light in each of the aerial images 173a, 173b.
  • a recipe can specify that of the N pulses, a certain number of pulses have a first primary wavelength that forms the aerial image 173a and a certain number of pulses have a second primary wavelength that forms the aerial image 173b.
  • the slit 176 and/or the mask 174 can move in in a scanning direction in the x-y plane such that only a portion of the wafer 170 is exposed at a given time or during a particular exposure scan (or exposure pass).
  • the size of the area on the wafer 170 exposed by the light beam 160 is determined by the distance between the blades in the non-scanning direction and by the length (distance) of the scan in the scanning direction.
  • the value of N is in the tens, for example, from 10-100 pulses. In other implementations, the value of N is greater than 100 pulses, for example, from 100-500 pulses.
  • An exposure field 479 of the wafer 170 is the physical area of the wafer 170 that is exposed in one scan of an exposure slit or window within the lithography exposure apparatus 169.
  • the wafer stage 171, the mask 174, and the objective arrangement 432 are fixed to associated actuation systems to thereby form a scanning arrangement.
  • one or more of the mask 174, the objective arrangement 432, and the wafer 170 (via the stage 171) can move relative to each other in the x-y plane.
  • these elements are not moved relative to each other along the z axis during an exposure pass or an exposure pass.
  • a flow chart of a process 500 is shown.
  • the process 500 is an example of a process for forming a three-dimensional semiconductor component or a portion of such a component.
  • the process 500 can be performed using the photolithography system 100 or 200.
  • the process 500 is discussed with respect to the system 200 shown in Fig. 2A.
  • the process 500 is also discussed with respect to Figs. 6A-10B.
  • the light beam 260 is directed toward the mask 174 (510).
  • the light beam 260 is a pulsed light beam that includes a plurality of pulses, each of which are separated from each other in time such as shown in Fig. 3C.
  • Figs. 6A and 6B show examples of optical spectra of a single pulse that is part of the light beam 260. Other pulses in the light beam 260 can have different optical spectra.
  • an optical spectrum 601 A of a pulse of light 600A is shown.
  • the pulse of light 600A has non-zero intensity within a band of wavelengths.
  • the band of wavelengths also may be referred to as the bandwidth of the pulse 600A.
  • the information shown in Fig. 6A is the instantaneous optical spectrum 601 A (or emission spectrum) of the pulse 600A.
  • the optical spectrum 601 A contains information about how the optical energy or power of a pulse of the light beam 260 is distributed over different wavelengths (or frequencies).
  • the optical spectrum 601 A is depicted in the form of a diagram where the spectral intensity (not necessarily with an absolute calibration) is plotted as a function of the wavelength or optical frequency.
  • the optical spectrum 601A can be referred to as the spectral shape or intensity spectrum of a pulse of the light beam 260.
  • the pulse 600A has a primary wavelength 602A, which, in the example of Fig. 6A, is the peak intensity.
  • the pulses of the light beam 260 and the aerial images formed by the pulses of the light beam 260 refers to the primary wavelengths of the pulses
  • the pulses include wavelengths other than the primary wavelength and the pulses have a finite bandwidth that may be characterized by a metric.
  • the full width of the spectrum 601 A at a fraction (X) of the maximum peak intensity of the spectral shape (referred to as FWXM) may be used to characterize the light beam bandwidth.
  • the width of the spectrum that contains a fraction (Y) of the integrated spectral intensity referred to as EY
  • EY the width of the spectrum that contains a fraction of the integrated spectral intensity
  • the pulse 600A is shown as an example of a pulse that can be in the light beam 260.
  • the pulse 600A When the pulse 600A is used to expose a portion of the wafer 120, the light in the pulse forms an aerial image.
  • the location of the aerial image in the z direction (Figs. 1C and 4) is determined by the value of the primary wavelength 602A.
  • the various pulses in the light beam 260 can have different primary wavelengths. For example, to generate two aerial images during a single exposure pass, some of the pulses of the light beam 260 have one primary wavelength (a first primary wavelength) and the other pulse of the light beam 260 have another primary wavelength (a second primary wavelength).
  • the first and second primary wavelengths are different wavelengths.
  • the wavelength difference between the first and second primary wavelengths can be referred to as the spectral separation.
  • the spectral separation can be, for example, 200 femtometers (fm) to 50 picometers (pm).
  • fm femtometers
  • pm picometers
  • the wavelengths of the various pulses in the light beam 260 can be different, the shape of the optical spectra of the pulses can be the same.
  • the light source 205 can dither or switch the primary wavelength between the first and second primary wavelengths on a pulse-to-pulse basis such that every pulse has a different primary wavelength than a pulse that immediately precedes or follows the pulse in time.
  • distributing the first and second primary wavelengths in this manner results in two aerial images at different locations in the z direction with the same intensity.
  • a certain portion (for example, 33%) of the pulses have the first primary wavelength, and the remainder (67% in this example) have the second primary wavelength.
  • the dose provided to a particular location in the wafer 170 along the z axis can be controlled by controlling the portion of the N pulses that have each of the first and second primary wavelengths.
  • the portion of pulses that are to have a particular primary wavelength for an exposure pass can be specified in a recipe file 259 that is stored on the electronic storage 252.
  • the recipe 259 specifies the ratio of the various primary wavelengths for an exposure pass.
  • the recipe 259 also can specify the ratio for other exposure passes, such that a different ratio can be used for other exposure passes and the aerial images can be adjusted or controlled on a field-by-field basis.
  • an optical spectrum 601B of a pulse 600B is shown.
  • the pulse 600B is another example of a pulse of the light beam 260.
  • the optical spectrum 601B of the pulse 600B has a different shape than the optical spectrum 601 A.
  • the optical spectrum 601B has two peaks that correspond to two primary wavelengths 602B_1 and 602B_2 of the pulse 600B.
  • the pulse 600B is part of the light beam 260.
  • the pulse 600B is used to expose a portion of the wafer 120, the light in the pulse forms two aerial images at different locations along the z axis on the wafer. The locations of the aerial images are determined by the wavelengths of the primary wavelengths 602B_1 and 602B_2.
  • the pulses shown in Figs. 6A and 6B can be formed by any hardware capable of forming such pulses.
  • a pulse train of pulses such as the pulse 600A can be formed using a line narrowing module similar to the line narrowing module 216C of Fig. 2C.
  • the wavelength of the light diffracted by the grating 291 depends on the angle of the light that is incident on the grating.
  • a mechanism to change the angle of incidence of light that interacts with the grating 291 can be used with such a line narrowing module to create a pulse train with N pulses for an exposure pass, where at least one of the N pulses has a primary wavelength that is different from the primary wavelength of another pulse of the N pulses.
  • one of the prisms 292, 293, 294, 295 can be rotated to change the angle of light that is incident on the grating 291 on a pulse-by-pulse basis.
  • the line narrowing module includes a mirror that is in the path of the beam 260 and is movable to change the angle of light that is incident on the grating 291.
  • a pulse such as the pulse 600B (Fig. 6B) also can be formed using a line narrowing module similar to the line narrowing module 216C of Fig. 2C.
  • a stimulated optical element such as an acousto-optic modulator
  • the acousto-optic modulator deflects incident light at an angle that depends on the frequency of an acoustic wave used to excite the modulator.
  • An acoustic modulator includes a material, such as glass or quartz, that allows acoustic waves to propagate, and a transducer coupled to the material.
  • the transducer vibrates in response to an excitation signal and the vibrations create acoustic waves in the material.
  • the acoustic waves form moving planes of expansion and compression that change the index of refraction of the material.
  • the acoustic waves act as a diffraction grating such that incident light is diffracted and exits the material at several different angles simultaneously.
  • Light from two or more of the orders can be allowed to reach the grating 291, and the light in each of the various diffraction orders has a different angle of incidence on the grating 291. In this way, a single pulse that includes two or more primary wavelengths can be formed.
  • a set of pulses of light are passed through the mask 174 toward the wafer 170 during a single exposure pass (520).
  • N pulses of light can be provided to the wafer 170 during the exposure pass.
  • the N pulses of light can be consecutive pulses of light in the beam 260.
  • the exposed portion of the wafer 170 sees an average of the optical spectrum of each of the N pulses over the exposure pass.
  • the average optical spectrum at the wafer 170 will be an optical spectrum that includes a peak at the first primary wavelength and a peak at the second primary wavelength.
  • Fig. 7 shows an example of an average optical spectrum 701 at the wafer 170.
  • the averaged optical spectrum 701 includes a first primary wavelength 702_1 and a second primary wavelength 702_2.
  • the first primary wavelength 702_1 and the second primary wavelength 702_2 are separated by a spectral separation 703 of about 500 fm however other combinations can also be considered.
  • the spectral separation 703 is such that the first primary wavelength 702_1 and the second primary wavelength 702_2 are distinct, and the average optical spectrum 701 includes a spectral region 704 of little to no intensity between the wavelengths 702_1 and 702_2.
  • Two or more aerial images are formed at the wafer 170 based on the average optical spectrum (530).
  • the average optical spectrum 701 and referring also to Fig. 8 A, two aerial images 873a and 873b are formed in a single exposure pass based on the N pulses.
  • the N pulses include a first set of pulses that have the first primary wavelength 702_1 and a second set of pulses that have the second primary wavelength 702_2. For example, these are single- peaked pulses such as shown in Fig. 6A.
  • the pulses that have the first primary wavelength 702_1 form the first aerial image 873a
  • the pulses that have the second primary wavelength 702_2 form the second aerial image 873b.
  • the aerial image 873a is formed at a first plane 878a
  • the aerial image 873b is formed at a second plane 878b.
  • the planes 878a and 878b are perpendicular to a direction of propagation of the light beam 260 at the wafer 170.
  • the planes 878a and 878b are separated along the z direction by a separation distance 879.
  • the separation distance 879 is larger than the depth of focus of the lithography apparatus 169 for an averaged optical spectrum that has a single primary wavelength.
  • the depth of focus may be defined for a dose value (an amount of optical energy provided to the wafer) as the range of focus along the z direction at which that dose provides a feature size that is within an acceptable range of feature sizes for the process that is being applied to the wafer 170.
  • the process 500 is able to increase the depth of focus of the lithography exposure apparatus 169 by providing more than one distinct aerial image at the wafer 170 during a single exposure pass. This is because the plurality of aerial images are each able to expose the wafer at a different location in the z direction with features that are within the acceptable range of feature sizes.
  • the process 500 is able to provide the lithography exposure apparatus 169 with a greater rage of depth of focus during a single exposure pass.
  • the operator of the lithography exposure apparatus 169 can control various parameters of the exposure process through the recipe file 259.
  • the operator of the lithography exposure apparatus 169 can receive information from a simulation program, such as the Tachyon Source-Mask Optimization (SMO) available from Brion, an ASML Company, and this information can be used to program or otherwise specify the parameters of the recipe file 259.
  • SMO Tachyon Source-Mask Optimization
  • the operator of the lithography exposure apparatus 169 may know that an upcoming lot is not going to require as much depth of focus as previously exposed lot.
  • the operator may specify a depth of focus and a dose variation to the simulation program, and the simulation program returns the value of the spectral separation 703 to achieve the desired parameters.
  • the operator may then specify the value of the spectral separation 703 for the upcoming lot by programing the recipe file 259 through the I/O interface 253.
  • the operator can use the simulation to determine whether or not a greater depth of focus (such as is possible by exposing the wafer 170 with a plurality of aerial images at distinct planes) is needed for a particular exposure pass.
  • the recipe file 259 can be structured so that, for example, the exposure pass used to form that particular portion of the semiconductor component has an averaged optical spectrum that includes a single primary wavelength.
  • the operator and/or simulator can receive information about the formed three- dimensional component as measured by the metrology system 172 or by another sensor.
  • the metrology system 172 can provide data relating to a sidewall angle of the formed 3D semiconductor component and the data can be used to program parameters in the recipe file 259 for a subsequent exposure pass.
  • Fig. 8B shows the aerial image 873a in the x-y plane (looking into the page in Fig. 8A) at the plane 878a.
  • the aerial images 873a and 873b are generally two-dimensional intensity patterns that are formed in the x-y plane. The nature of the intensity pattern depends on the characteristics of the mask 174.
  • the first and second planes 878a, 878b are portions of the wafer 170. As illustrated in Fig. 8B, the first plane 878a can be only a small portion of the entire wafer 170.
  • the value of the separation distance 879 depends on the spectral separation 703 and on properties of the optical system 275.
  • the value of the separation distance 879 can depend on the focal length, aberration, and other properties of lenses and other optical elements in the optical system 275.
  • the separation distance 879 can be determined from Equation 1 :
  • AD C * l Equation (1), where AD is the separation distance 879 in nanometers (nm), C is the chromatic aberration (defined as the distance the focal plane moves in the propagation direction for a wavelength change, which is a known property of the projection lens 177), and Dl is the spectral separation 873 in picometers.
  • C the chromatic aberration
  • Dl the spectral separation 873 in picometers.
  • the spectral separation 873 can be about 10 fm.
  • a recipe or process control program 259 can be stored on the electronic storage 252 of the control system 250.
  • the recipe 259 can be modified or programmed to be customized to a particular exposure apparatus or a type of exposure apparatus.
  • the recipe 259 can be programmed when the lithography system 200 is manufactured and or the recipe 259 can be programmed via, for example, the I/O interface 253, by an end user or other operator familiar with the performance of the system 200.
  • the recipe 259 also can specify a different separation distance 879 for different exposure passes used to expose different areas of the wafer 170. Additionally or alternatively, the recipe 259 can specify the separation distance 879 on a per-lot or per-layer basis or on a per-wafer basis. A lot or a layer is a group of wafers that are processed by the same exposure apparatus under the same nominal conditions.
  • the recipe 259 also allows specification of other parameters related to the aerial images 873a, 873b, such as the dose provided by each image. For example, the recipe 259 can specify a ratio of the number of pulses in the N pulses that have the first primary wavelength 702_1 to the number of pulses that have the second primary wavelength 702_2. These other parameters also can be specified on a per-field, per-lot (or per-layer), and or per-wafer basis.
  • the recipe 259 can specify that some layers are not exposed with the first primary wavelength 702_1 and the second primary wavelength 702_2 and are instead exposed with a pulse that has an optical spectrum that includes a single primary wavelength.
  • Such an optical spectrum can be used, for example, when a planar semiconductor component is to be formed instead of a three- dimensional semiconductor component.
  • the I/O interface 253 allows an end-user and/or manufacturer to program or create the recipe to specify the number of primary wavelengths, including a scenario in which a single primary wavelength is used, for example, for a particular layer or lot.
  • the average optical spectrum 701 can have more than two primary wavelengths (for example, three, four, or five primary wavelengths), each of which are separated from the nearest other primary wavelength by a spectral separation and a region such as the region 704.
  • the I/O interface 253 allows an end-user and/or manufacturer to program or create the recipe to specify these parameters.
  • a three-dimensional (3D) semiconductor component is formed (540).
  • Fig. 9A shows a cross- sectional view of an example of a 3D semiconductor component 995.
  • Fig. 9B shows the wafer 170 and the component 995 in the x-y plane at the first plane 878a.
  • the 3D semiconductor component 995 can be a complete component or a portion of a larger component.
  • the 3D semiconductor component 995 can be any type of semiconductor component that has features that are not all formed at one z location in the wafer 170.
  • the 3D semiconductor component can be a device that includes recesses or openings that extend along the z axis.
  • the 3D semiconductor component can be used for any type of electronic application.
  • the 3D semiconductor component can be all or part of a 3D NAND flash memory component.
  • a 3D NAND flash memory is a memory in which memory cells are stacked along the z axis in layers.
  • the 3D semiconductor component 995 includes a recess 996 that is formed in a periphery 999.
  • the recess 996 includes a floor 997 and a sidewall 998, which extends generally along the z axis between the periphery 999 and the floor 997.
  • the floor 997 is formed by exposing photoresist at the plane 878b with light that is in the second aerial image 873b (Fig. 8A).
  • Features on the periphery 999 are formed using light that is in the first aerial image 873a (Fig. 8A).
  • Using the process 500 also can result in a sidewall angle 992 being equal to 90° or closer to 90° than is possible with other processes.
  • the sidewall angle 992 is the angle between the floor 997 and the sidewall 998. If the sidewall 998 extends in the x-z plane and the floor extends in the x-y plane, the sidewall angle 992 is 90° and can be considered vertical in this example. A sidewall angle that is closer to vertical is desirable because, for example, it may allow for more well-defined features in a 3D semiconductor component.
  • the process 500 achieves a sidewall angle 992 that is equal or close to 90° because the locations of the first aerial image 873a and the second aerial image 873b (the first plane 878a and the second plane 878b, respectively) are separate images that are in different parts of the wafer 170. Forming separate aerial images in a single exposure pass allows the quality of each of the images to be improved resulting in a more defined feature that is more vertically oriented as compared to a feature formed by a single aerial of lower quality.
  • Figs. 10A and 10B are examples of simulated data relating to the process 500.
  • Fig. 10A shows three plots 1001, 1002, 1003 of aerial image intensity versus mask position along the y axis (Fig. 9A). Each of the plots 1001, 1002, 1003 represents intensity versus mask position for one aerial image.
  • the plot 1001 represents a simulation of an average optical spectrum that forms two aerial images during a single exposure pass, such as discussed above with respect to Fig. 5.
  • the plot 1002 represents a simulation of a situation in which the wafer stage is tilted according to ASML’s EFESE technique, which is a procedure for increasing the depth of focus to facilitate the printing of three-dimensional features (such as vias and holes) on a wafer.
  • EFESE technique the wafer stage is tilted at an angle to scan the aerial image through the focus while exposing the wafer.
  • the EFESE technique generally results in a greater depth of focus.
  • Fig. 10A only the plot 1002 represents data simulated using the EFESE technique. The remaining data shown on Fig. 10A did not employ the EFESE technique.
  • the plot 1003 represents data from a simulation of a best focus based on dose.
  • Fig. 10A shows that forming two or more aerial images in a single exposure pass can produce similar contrast as tilting the wafer stage. A greater contrast indicates that the three-dimensional features that are at different locations along the z axis (Fig. 8A) are more likely to be properly formed.
  • Fig. 10B shows three plots 1004, 1005, 1006 of critical dimension as a function of the focus position for three different aerial images, with each aerial image averaged over an exposure pass.
  • the plot 10004 represents data from a simulation in which no EFESE technique was applied and a single aerial image was formed.
  • the plot 1005 represents data from a simulation in which the EFESE technique was applied.
  • the EFESE technique increases the depth of focus as compared to the no-EFESE simulation because the critical dimension value remains the same for a further distance from zero focus.
  • the plot 1005 represents data from a simulation in which two aerial images were generated in a single exposure pass and no EFESE technique was employed.
  • the depth of focus for the no-EFESE simulations using multiple aerial images are on par or better than the EFESE technique.
  • the process 500 can be used to achieve a greater depth of focus in a single exposure pass without relying on a technique such as EFESE.
  • control system 1150 includes the processor 251, the electronic storage 252, and the I/O interface 253 that together are configured to interface with the spectral feature selection module 258 within an optical source 1105 to thereby enable adjustment of a spectral feature of a pulsed light beam 1160 output from the optical source 1105.
  • control system 1150 includes an energy control module 1161E configured to provide an excitation signal 1168E to the optical source 1105, the excitation signal 1168E being used to control electrodes within a master oscillator of the optical source 1105 (such as the master oscillator 212 of Fig. 2A).
  • the energy control module 1161E can also be configured to provide an excitation signal to one or more other oscillators within the optical source 1105.
  • the control system 1150 can be used with any type of optical source 1105.
  • the control system 1150 can be used with an optical source 1105 that includes a single optical oscillator.
  • the control system 1150 can be used with a multi-stage optical source 1105 that includes one or more optical oscillators and one or more power amplifiers, such as, for example, the optical source 205 of Fig. 2A.
  • the optical source 1105 provides the pulsed light beam 1160 to the lithography exposure apparatus 1169.
  • An energy control apparatus 1160E is formed from the energy control module 1161E and an optical detection system 1145E.
  • the optical detection system 1145E is configured to sense light (such as the pulsed light beam 1160) and to produce an energy property signal 1146E.
  • the optical detection system 1145E is any type of optical sensor or detector that is capable of measuring optical energy in the pulsed light beam 1160 and producing the energy property signal 1146E based on this measurement.
  • the energy property signal 1146E includes information about the energy in one or more pulses of the light beam 1160.
  • the energy property can be, for example, an optical energy of an optical pulse in the pulsed light beam 1160 or an energy error associated with an optical pulse in the pulsed light beam 1160.
  • the energy control module 1161E generates the excitation signal 1168E or causes the excitation signal 1168E to be generated by a separate device, such as a source supply 1197E, which is configured to amplify the signal and to apply voltage to one or more electrodes 217, as shown in Fig.
  • the excitation signal 1168E When the excitation signal 1168E is applied to the one or more optical oscillators in the optical source 1105, that optical oscillator generates a pulse of light.
  • the excitation signal 1168E and the pulses in the light beam 1160 are time-varying signals.
  • individual instances of the excitation signal 1168E, the pulses, and the energy property signal 1146E can be indexed by k, where k is an integer number.
  • the kth instance of the excitation signal 1168E (the excitation signal 1168E(k)) produces pulse k of the light beam 1160.
  • the energy control module 116 IE receives an instance of the energy property signal 1146E and generates an instance of the excitation signal 1168E for each pulse in the light beam 1160.
  • the amount of optical energy (that is, energy in the pulse of the light beam 1160) produced in response to the application of the excitation signal 1168E depends on the characteristics of the excitation signal 1168E.
  • the excitation signal 1168E can be a train of voltage pulses, and the characteristics of the excitation signal 1168E can include an amplitude and/or temporal duration of the voltage pulses.
  • the energy control module 1161E determines the excitation signal 1168E or characteristics of the excitation signal 1168E. In the discussion that follows, the energy control module 116 IE and its various implementations are described as generating or determining the excitation signal 1168E.
  • the energy control module 1161E (or any of its various implementations) generates characteristics of the signal 1168E that are provided to the source supply 1197E that generates the signal 1168E based on the characteristics.
  • the excitation signal 1168E can be a high-voltage signal that is generated by the source supply 1197E.
  • the energy control module 1161E is implemented to enable spectral feature dependent (for example, wavelength-dependent) dose or energy control at the lithography exposure apparatus 1169. Specifically, the energy control module 1161E enables the dose and/or energy of a current pulse in the light beam 1160 to be changed relative to a prior and adjacent pulse in the light beam 1160.
  • This change can be performed for each pulse of the light beam 1160 so that the energy changes with each pulse of the light beam 1160.
  • the energy control module 1161E is configured to provide the pulse-to-pulse control of the dose and/or energy of the pulses in the light beam 1160.
  • the optical source 1105 includes the spectral feature selection module 258, which couples to light that propagates in the optical source 1105 to enable the fine tuning of the spectral features such as wavelength and bandwidth within the master oscillator 212.
  • the spectral feature selection module 258 can change its configuration with each pulse or with every n th pulse, where n is an integer greater than 1.
  • the optical oscillator 212 is associated with a plurality of transfer functions, each transfer function being associated with a particular configuration of the spectral feature selection module 258 and each transfer function relating to an efficiency characteristic of that configuration.
  • a particular transfer function relates characteristics of the excitation signal 1168E to an amount of optical output (within the pulsed light beam 224 or 260) produced by the optical oscillator 212 while in that particular configuration.
  • a transfer function of a particular configuration of the optical oscillator 212 (and a particular configuration of the spectral feature selection module 258) relates an amount of voltage applied to the electrodes 217 in the chamber 214 to the optical energy produced by the gain medium within the chamber 214.
  • the transfer function TF (the optical energy produced by the single optical oscillator 212 as a function of provided excitation energy) varies with the wavelength of the emitted pulsed light beam.
  • Fig. 11B includes a transfer function TF(1), which is the efficiency of the optical oscillator 212 when the center or primary wavelength of the pulse is a first wavelength (lr ⁇ ), and a transfer function TF(2), which is the efficiency of the optical oscillator 212 when the center or primary wavelength of the pulse is a second wavelength (lr2)
  • the transfer functions TF(1) and TF(2) relate the voltage V applied to the excitation mechanism of the optical oscillator 212 to the optical energy of a pulse of the light beam 1160 produced by the optical oscillator 212.
  • the transfer functions TF(1) and TF(2) are both locally close to linear but have different slopes and different y- intercepts.
  • HVSetPoint is a discharge voltage set point
  • OffsetV is a voltage offset applied to the excitation mechanism of the optical oscillator 212
  • OffsetE is an energy offset
  • the optical oscillator 212 alternates between producing a pulse of light at the first primary wavelength (lr ⁇ ) and a pulse of light at the second primary wavelength (lr2) to produce a pulsed light beam 1160 that has a spectral peak at the first primary wavelength and a spectral peak at the second primary wavelength.
  • the pulses of light at the first primary wavelength (lr ⁇ ) are generally intermingled (and in some implementations, interleaved) with the pulses of light at the second primary wavelength (lr2).
  • the system 1160 seeks to maintain a first target energy Etargetl for the pulses of light at the first primary wavelength (lr ⁇ ) and a second target energy Etarget2 for the pulses of light at the second primary wavelength (lr2).
  • the kth pulse has an energy El and a primary wavelength of lr2.
  • the optical element within the spectral feature selection module 258 is actuated such that the primary wavelength of the kth+1 pulse will be lr2.
  • the system 1160 determines the voltage to apply to the optical oscillator 212 to produce the kth+1 pulse based on an estimate of the transfer function TF(2), which is an accurate representation of the efficiency for the configuration of the optical oscillator 212 when it is configured to produce pulses in which the primary wavelength is the second primary wavelength (lr2).
  • the energy control module 1161E can be configured to determine the excitation signal 1168E based on the transfer function associated with the particular configuration of the spectral feature selection module 258 used to produce the subsequent pulse of light.
  • the spectral feature selection module 258 includes at least one prism, and each transfer function can be associated with a different position of the at least one prism.
  • the energy control module 1161E corrects or adjusts the excitation signal 1168E using a correction module and also a modeling module that estimates the transfer function of each state of the spectral feature selection module 258 so that the energy control module 116 IE can remove or reduce energy disturbances. Moreover, the energy control module 1161E performs this control on a pulse-to- pulse basis, to account for the errors that arise with each pulse.
  • an implementation 1261E of the energy control module 1161E is shown for use with an optical oscillator 1212E.
  • the energy control module 1261E is configured to be implemented as a part of the control system 1150 or 250.
  • the optical oscillator 1212E can be one of two or more optical oscillators in a multi-staged optical source (such as the optical source 205 of Fig. 2A).
  • the output of the optical oscillator 1212E is a pulsed light beam such as the seed light beam 224 or the output light beam 260 (Fig. 2A).
  • a first energy control module 126 IE can be configured for the master oscillator 212 while a second energy control module 1261E can be configured for the power amplifier 230 (see Fig. 2A).
  • a single energy control module 1261E can be configured for both the master oscillator 212 and the power amplifier 230 (see Fig. 2A).
  • the energy control module 1261E includes a comparator 1263E and an energy controller 1262E.
  • the energy control module 1261E also includes a target energy generator 1270E.
  • the comparator 1263E receives the energy property signal 1246E from the optical detection system 1145E and also receives a target energy Etarget 127 IE from the target energy generator 1270E.
  • the comparator 1263E implements a comparison function such as, for example, a subtraction to determine an error signal 1266E.
  • the energy controller 1262E includes one or more modules configured to determine an excitation signal 1268E, which corresponds to the excitation signal 1168E referenced in Fig. 11A.
  • the excitation signal 1268E takes into account the error signal 1266E and also takes into account the variation in the transfer function of the optical oscillator 1212E, as discussed below.
  • the two elongated electrodes 217 include a cathode 217-a and an anode 217-b contained in the discharge chamber 214.
  • a potential difference between the cathode 217-a and the anode 217-b forms an electric field in the gaseous gain medium 219.
  • the potential difference is generated by controlling the source supply 1197E to apply voltage to the cathode 217-a and/or the anode 217-b.
  • the source supply 1197E is controlled by the excitation signal 1168E.
  • the excitation signal 1168E includes information sufficient to cause the source supply 1197E to produce a voltage signal 1168Ev and to apply the voltage signal 1168Ev to the master oscillator 212 in accordance with the trigger signal 330 (Fig. 3C).
  • the voltage signal 1168Ev has an amplitude that is specified by the excitation signal 1168E.
  • the source supply 1197E applies the voltage signal 1168Ev to thereby apply the voltage of a particular amplitude to the cathode 217-a and/or the anode 217-b such that the electric field provides energy to the gain medium 219 sufficient to cause a population inversion and to enable generation of a pulse of the light beam 224 by way of stimulated emission. Repeated creation of such a potential difference forms a train of pulses, which are emitted as the light beam 224, and thus the light beam 260 (Fig. 2A).
  • the comparator 1263E implements a comparison function such as a subtraction.
  • the comparator 1263E receives the energy property signal 1246E from the optical detection system 1145E and the value of the Target energy Etarget 127 IE from the target energy generator 1270E.
  • the energy property signal 1246E includes an indication of an amount of optical energy in a pulse k-1, which is the pulse immediately before pulse k.
  • the target energy Etarget 1271E is the value of the target or desired optical energy for a sub set of optical pulses in the light beam 1160.
  • the target energy Etarget 1271E is a pre-defined optical energy that is associated with acceptable or optimal performance of the photolithography system 1100.
  • the value of Etarget 127 IE can be stored in electronic storage 252 or another location within the optical source 1105 and can be ready for use by the comparator 1263E when needed. In some implementations, the value of Etarget 127 IE can be instructed by the lithography exposure apparatus 1169 (as shown by the arrow 1165).
  • the energy control module 1161E is implemented to enable spectral feature dependent dose or energy control at the lithography exposure apparatus 1169.
  • the target energy generator 1270E provides or determines a target energy Etarget 1271E that is associated with the spectral property (such as the primary wavelength lr) of a pulse of the light beam 1160 produced by the optical oscillator 1212E.
  • Fig. 14 shows a table in which each target energy Etarget 1271E_i is correlated with each possible primary wavelength lr 1402_i of set of pulses of the light beam 1160, where i is an integer greater than 1 and having a maximum value of M. This table can be stored within optical source 1105 or the lithography exposure apparatus 1169 and accessed by the target energy generator 1270E upon production of a pulse of the light beam 1160.
  • Fig. 15A shows a graph of target energies Etarget 157 IE relative to four primary wavelengths 1502, each of the primary wavelengths 1502 being associated with a set of light beam pulses.
  • primary wavelength 1502a is associated with target energy Etarget 157 lEa
  • primary wavelength 1502b is associated with target energy Etarget 157 lEb
  • primary wavelength 1502c is associated with target energy Etarget 1571Ec
  • primary wavelength 1502d is associated with target energy Etarget 157 lEd.
  • Fig. 15A shows a graph of target energies Etarget 157 IE relative to four primary wavelengths 1502, each of the primary wavelengths 1502 being associated with a set of light beam pulses.
  • primary wavelength 1502a is associated with target energy Etarget 157 lEa
  • primary wavelength 1502b is associated with target energy Etarget 157 lEb
  • primary wavelength 1502c is associated with target energy Etarget 1571Ec
  • primary wavelength 1502d is associated with target energy Etarget 157 lEd.
  • each aerial image 1573a, 1573b, 1573c, 1573d is formed at the wafer 170 during the same exposure pass, each aerial image 1573a, 1573b, 1573c, 1573d being formed at respective and distinct planes 1578a, 1578b, 1578c, 1578d along the z axis.
  • the location of the plane depends on the primary wavelength 1502.
  • the aerial image 1573a is formed at the plane 1578a, the location along the z axis depending on the primary wavelength 1502a.
  • each aerial image 1573a, 1573b, 1573c, 1573d is associated with a respective distinct energy 1571Ea, 1571Eb, 1571Ec, 1571Ed.
  • each distinct energy 1571Ea, 1571Eb, 1571Ec, 1571Ed is represented by a different level of shading within the respective aerial image 1573a, 1573b, 1573c, 1573d.
  • the target energy generator 1270E can access information or data from the optical source 1105 about the primary wavelength of the pulse k-1. For example, if the energy property signal 1246E is associated with the pulse k-1, then the target energy generator 1270E can output the target energy Etarget 127 IE that is associated with the primary wavelength of the pulse k-1. As another example, the target energy generator 1270E can output the target energy Etarget 1271E based on the pulse number or index. For example, with reference to Figs.
  • the target energy generator 1270E determines that the target energy Etarget 1271E for pulse k-1 is 1571Ec.
  • the target energy generator 1270E determines that the target energy Etarget 1271E for pulse k-lis 1571Ea.
  • the value of Etarget 127 IE and/or the indication of the amount of optical energy in the energy property signal 1246E can be processed prior to being received by the comparator 1246E. For example, if the value of Etarget 127 IE is in units of energy (Joules) and the indication of the amount of optical energy in the energy property signal 1246E is in units of power (Watts), then the indication can be converted to units of energy (Joules) prior to being received at the comparator 1263E.
  • the comparator 1263E determines an energy error 1266E associated with pulse k-1 of the light beam 1160, the energy error 1266E corresponding to the difference between the amount of energy in the pulse k-1 and the Etarget 127 IE.
  • the energy error 1266E is provided to the energy controller 1272E, which determines the excitation signal 1268E.
  • the characteristics of the excitation signal 1268E are based on the energy error 1266E (which in turn is based on the indication of the amount of energy in the energy property signal 1246E).
  • the energy controller 1272E corrects the excitation signal 1268E to account for the variation in the transfer function of the optical oscillator 1212E.
  • the transfer function varies because the spectral property (wavelength) of the pulses in the light beam 1160 are intentionally not ah the same. For example, the center or primary wavelength of each pulse can change on a pulse-by- pulse basis changing the configuration of the spectral feature selection module 258 prior to producing the pulse.
  • the primary wavelength can alternate between a plurality of values to form a pulsed light beam 1160 that has a spectral peak at each primary wavelength, where any two peaks are separated from each other by a spectral distance that is the difference between the primary wavelengths of the two peaks. There is little to no light in the pulsed light beam at wavelengths between two adjacent primary wavelengths.
  • the corrected excitation signal 1268E is applied to the optical oscillator 1212E to correct for the variation of the efficiency of the optical oscillator 1212E.
  • the energy control module 1261E causes the energy of the pulse for a particular primary wavelength in the pulsed light beam 1160 to be at or within an acceptable range of the target energy 127 IE that is associated with that particular primary wavelength.
  • an implementation 1661E of the energy control module 1161E is shown for use with an optical oscillator 1212E.
  • the energy control module 1661E includes a plurality of energy controllers 1672E, one for each primary wavelength lr.
  • two energy controllers 1672E_1 and 1672E_2 are shown, one for each of two primary wavelengths so that the optical oscillator 1212E produces pulses having a first primary wavelength lr ⁇ at a first target energy 1671E_1 and a second primary wavelength lr2 at a second target energy 1671E_2.
  • the energy control module 1661E can include more than two energy controllers 1672E, and as many energy controllers 1672E as there are primary wavelengths in the light beam 1160.
  • Each of the energy controllers 1672E can be of any suitable design or operation.
  • any one energy controller 1672E within the energy control module 1661E can have a different design or operation from the other energy controllers 1672E within the energy control module 166 IE.
  • the energy control module 166 IE includes a set of comparators 1663E, one for each energy controller 1672E.
  • a first comparator 1663E_1 is associated with the first energy controller 1672E_1 and a second comparator 1663E_2 is associated with the second energy controller 1672E_2.
  • the energy control module 1661E also includes a target energy generator 1670E that generates the target energy Etarget for each primary wavelength lr.
  • the target energy generator 1670E generates a first target energy Etarget 1671E_1 for the first primary wavelength lr ⁇ , the first target energy Etarget 1671E_1 being provided to the first comparator 1663E_1, and a second target energy Etarget 1671E_2 for the second primary wavelength lr2, the second target energy Etarget 1671E_2 being provided to the second comparator 1663E_1.
  • the energy control module 166 IE includes a switch 1646Es that is configured to determine where to send the energy property signal 1646E.
  • the switch 1646Es provides the energy property signal 1646E to the first comparator 1663E_1 if the current pulse has the first primary wavelength lr ⁇ and the switch 1646Es provides the energy property signal 1646E to the second comparator 1663E_2 if the current pulse has the second primary wavelength lr2.
  • respective switches can be implemented at the comparators 1663E_1, 1663E_2.
  • the energy controller such as the energy controller 1272E configured to operate on all of the primary wavelengths lr or the energy controllers 1672E_1, 1672E_2, each configured to operate on a single primary wavelength lr, can have any suitable design or operation.
  • a suitable energy controller is discussed with reference to Figs. 17-20. Any one of these energy controllers can be implemented as any one of the energy controllers 1272E, 1672E_1, or 1672E_2.
  • an implementation 1772E of an energy controller uses a notch filter.
  • the energy controller 1772E includes a delay module 1767E, an excitation determination module 1762E, and a correction module 1764E.
  • the delay module 1767E receives the energy error 1766E from the comparator 1763E, which can be any one of the comparators 1263E, 1663E_1, 1663E_2.
  • the delay module 1767E introduces a time delay into the energy error 1766E in order to ensure proper causality; so that the action taken by the energy controller 1772E is not applied to the pulse for which the measurement is received (from the energy property signal 1246E). While the delay module 1767E is shown as a separate block, its function can be implemented within the optical detection system 1145E or the excitation determination module 1762E.
  • the energy error 1766E is provided to the excitation determination module 1762E, which determines the excitation signal 1768Ep.
  • the characteristics of the excitation signal 1768Ep are based on the energy error 1766E, which in turn is based on the indication of the amount of energy in the energy property signal 1246E, 1646E.
  • the excitation determination module 1762E can determine how much to adjust the voltage to the electrodes of the oscillator 1212E to offset the error in the energy of the light beam output from the oscillator 1212E.
  • the excitation signal 1768Ep is provided to the correction module 1764E.
  • the correction module 1764E determines a corrected excitation signal 1768E based on the excitation signal 1768Ep. Specifically, the correction module 1764E corrects the excitation signal 1768Ep to account for the variation in the transfer function of the optical oscillator 1212E.
  • the transfer function varies because the spectral properties of the pulses in the light beam 1160 are intentionally not all the same. For example, the center or primary wavelength lr of each pulse can change on a pulse-by-pulse basis changing the configuration of the spectral feature selection module 258 prior to producing the pulse.
  • the primary wavelength can alternate between a plurality of values to form a pulsed light beam 1160 that has a spectral peak at each primary wavelength, where any two peaks are separated from each other by a spectral distance that is the difference between the primary wavelengths of the two peaks. There is little to no light in the pulsed light beam at wavelengths between two adjacent primary wavelengths.
  • the correction module 1764E implements a filter (such as a notch filter), which determines the corrected excitation signal 1768E based on at least the transfer function TF(k) of the optical oscillator 1212E when it produces the kth pulse, the energy error 1766E for the kth pulse, a cumulative energy error for the kth pulse, one or more values of prior excitation signals for pulses having the same primary wavelength as the kth pulse, and one or more tuning parameters or gains that are related to energy and/or dose error.
  • a notch filter rejects signals having a frequency in a frequency band and transmits signals having frequencies outside of the frequency band.
  • the notch filter is configured to reject energy disturbances that can occur due to using pulses of light from different configurations (different transfer functions) of the optical oscillator 1212E.
  • the notch filter can be expressed by the following equation: where k is an integer number that indexes the pulse number, V sp is the corrected excitation signal 1768E and specifically V sp (k+1) is the corrected excitation signal 1768E for the k+1 pulse, G N is KH/KE, where KH is a tuning parameter of gain related to dose error, KE is a tuning parameter or gain related to energy error, and Vservo is a voltage command that is calculated according to Equation (3) as follows: Equation (3), where e(k) is the energy error 1766E for the kth pulse, D(k) is the cumulative energy error or dose error for the kth pulse, and dEdV(k) is the transfer function of the optical oscillator 1212E when it produces the kth pulse.
  • the corrected excitation signal 1768E is applied to the optical oscillator 1212E to correct for the variation of the efficiency of the optical oscillator 1212E.
  • the energy control module 1261E causes the energy of the pulse for a particular primary wavelength in the pulsed light beam 1160 to be at or within an acceptable range of the target energy (such as Etarget 1271E, or Etarget 1671E_1, Etarget 1671E_2) that is associated with that particular primary wavelength.
  • an implementation 1872E of an energy controller uses a Kalman filter, which uses linear quadratic estimation.
  • the energy controller 1872E includes a delay module 1867E that receives an error signal from a comparator 1863E, which can be any one of the comparators 1263E, 1663E_1, 1663E_2. As discussed above, the delay module 1767E introduces a time delay into the energy error 1866E in order to ensure proper causality; so that the action taken by the energy controller 1872E is not applied to the pulse for which the measurement is received (from the energy property signal 1246E). While the delay module 1867E is shown as a separate block, its function can be implemented within the optical detection system 1145E or another component of the energy controller 1872E.
  • the energy controller 1872E includes an excitation determination module 1862E, a correction module 1864E and a second comparator 1869E.
  • the excitation determination module 1862E determines an excitation signal 1868Ep based on the energy error 1866E output from the delay module 1867E.
  • the excitation determination module 1862E includes a set of transfer function models, with each transfer function model being associated with a respective one of the states of the optical oscillator 1212E.
  • each transfer function TF of the optical oscillator 1212E is associated with a particular configuration of the spectral feature selection module 258 that produces a distinct primary wavelength lr and each transfer function TF relates to an efficiency characteristic of that configuration.
  • the excitation determination module 1862E selects the model M(TF) associated with the transfer function TF of the optical oscillator 1212E that produced the kth pulse in order to calculate the excitation signal 1868Ep. In equation form, this can be represented by:
  • Equation (4) where k is an integer greater than or equal to 1 that represents the pulse number of a pulse of the light beam 1160, Ch k is the state of the optical oscillator 1212E that produces the kth pulse in the light beam 1160, and dedv(Ch k ) is the model M(TF) that models the transfer function of the optical oscillator 1212E that produced the kth pulse. V * and E * are determined as part of the modeling.
  • V(k+1) is th excitation signal 1868Ep that is determined for the k+1 pulse.
  • the correction module 1864E is implemented as a Kalman filter, which rejects pulse-to-pulse energy disturbances with known periods efficiently.
  • the Kalman filter 1864E uses the energy error 1866E from the comparator 1863E and the excitation signal 1868Ep from the excitation determination module 1862E to determine an output signal 1864Eo.
  • the output signal 1864Eo is provided to the second comparator 1869E.
  • the second comparator 1869E determines a corrected excitation signal 1868E based on the output signal 1864Eo and the excitation signal 1868Ep.
  • the output signal 1864Eo of the Kalman filter 1864E is based on a factor that is directly related to the energy error 1866E of the kth pulse, the model M(TF) associated with the period at which the configuration of the spectral feature selection module 258 changes, and the excitation signal 1868E that was applied to produce the kth pulse.
  • the output signal 1864Eo of the Kalman filter 1864E also takes into account a gain and a tuning parameter of the Kalman filter 1864E.
  • KXpost(k) KXpred(k)+K_K(k)*Ke(k) Equation (6), where K_K is the gain of the Kalman filter 1864E is given by: Equation (7), Equation (8), where Error(k) is the energy error 1866E of the kth pulse, dedv(M(TF)) is the model that is associated with the optical oscillator 1212E used to produce the kth pulse in the light beam 1160, and HVcommand(k) is the excitation signal applied to produce the kth pulse.
  • KPpred(k+l) is given by:
  • Equation (10) where C is a tuning parameter of the Kalman filter 1864E and can be equal to 1 in this implementation, and R is a tuning parameter.
  • the second comparator 1869E determines the corrected excitation signal 1868E as follows:
  • HVSP(k) H V Command(k) + HVDefault - KXpred(k), Equation (11), where HVSP(k) is the corrected excitation signal 1868E, HVCommand(k) is the uncorrected excitation signal 1868Ep determined by the excitation determination module 1862E for the kth pulse, HVDefault is a parameter that estimates a nominal excitation signal for the transfer function TF of the optical oscillator 1212E for the kth pulse, and KXpred(k) is the output signal 1864Eo of the Kalman filter 1864E for the kth pulse.
  • the value of HVDefault can be stored in electronic storage and retrieved by the energy controller 1872E when needed.
  • the value of HVDefault can be a magnitude of a voltage and can be, for example, a value that is greater than 100 Volts.
  • an implementation 1961E of the energy control module 1161E uses a feed-forward approach to reject or reduce pulse-to-pulse energy disturbances or energy variations that occur due to intentionally changing the configuration of the spectral feature selection module 258 associated with the optical oscillator 1212E in order to vary the spectral property of the light beam 1160 produced by the optical oscillator 1212E.
  • the energy control module 1961E relies on a set of estimates EvsV ⁇ p), each estimate being of the relationship between the input (the excitation signal or V) to the optical oscillator 1212E and the output (the energy E of the light beam 1160) from the optical oscillator 1212E for each primary wavelength lr.
  • the energy control module 1961E includes a target energy generator 1970E (that operates similarly to the target energy generator 1270E), a comparator 1963E, and an energy controller 1972E.
  • the energy controller 1972E includes the delay module 1967E and an excitation determination module 1962E.
  • the output of the delay module 1967E is an energy error 1966E output from the comparator 1963E, the energy error 1966E corresponding to a measure of the difference between an energy property signal 1946E (which is the energy in the previous pulse, see Fig. 19A) and an energy target 197 IE.
  • the excitation determination module 1962E determines a corrected excitation signal 1968E and provides the corrected excitation signal 1968E to the optical oscillator 1212E.
  • Fig. 19C is a block diagram of the excitation determination module 1962E.
  • the excitation determination module 1962E can include the feedback controller FC.
  • the feedback controller FC is a proportional-integral-derivative (PID) controller that receives the error signal 1966E and produces an output that is applied to one of the transfer functions that are selected downstream (as discussed next).
  • PID controller includes proportional, integral, and derivative terms.
  • any feedback controller can be used as the feedback controller FC.
  • the excitation determination module 1962E includes a transfer function selector 1974E, which selects one transfer function TF(1), TF(2), ... TF(N).
  • Each of the transfer functions TF(1), TF(2), ... TF(N) is an estimated transfer function of the optical oscillator 1212E for a particular primary wavelength lr, and each of the transfer functions TF(1), TF(2), ... TF(N) is associated with a particular configuration of the spectral feature selection module 258 (Fig. 13).
  • the spectral feature selection module 258 has N different configurations, each of which is associated with a different spectral parameter (for example, center or primary wavelength or bandwidth) of the output light beam 1160.
  • N is an integer number that is greater than one and indexes all of the possible configurations of the spectral feature selection module 258 that are relevant to the particular application.
  • Each of the N configurations of the spectral feature selection module 258 is associated with a respective transfer function TF(1), TF(2), ... TF(N) of the optical oscillator 1212E.
  • the index value of N associated with a particular one of the transfer functions TF(1), TF(2), ... TF(N) can be stored in a look-up table or database with data that defines the transfer function TF and a center or primary wavelength lr produced by that configuration of the spectral feature selection module 258.
  • TF(N) can be stored on the electronic storage 252 and accessible to the energy control module 1961E.
  • the transfer functions TF(1), TF(2), ... TF(N) can be associated with the N configurations by the manufacturer, or can be provided by the operator of the system 1100, or can be estimated and updated online using the history of inputs (discharge voltage) and output (measured energy).
  • the transfer function selector 1974E determines which of the transfer functions TF(1), TF(2),
  • ... TF(N) is associated with the configuration that produces the kth pulse of the output light beam 1160 emitted from the optical oscillator 1212E.
  • the transfer function selector 1974E can select from among the transfer functions TF(1), TF(2), ... TF(N) by implementing a remainder function, which returns the remainder of a division operation that divides k by M, where M is an integer number that represents the number of the N configurations of the spectral feature selection module 258 that are alternated between or cycled through to produce optical pulses and k indexes the pulse number.
  • M is two, N, or any number greater than 2 and less than or equal to N.
  • the center or primary wavelength lr of optical pulses produced by the optical oscillator 1212E varies pulse-by-pulse according to a pre-determined recipe.
  • the optical oscillator 1212E and the spectral feature selection module 258 can be controlled such that the primary wavelength lr cycles among four pre-determined primary wavelengths (such as those shown in Figs. 15A and 15B) in a sequential manner.
  • the transfer function selector 1974E selects the transfer function TF(2) for the second and sixth pulses, the transfer function TF(3) for the third and seventh pulses, and so on.
  • the error signal 1966E is provided to the selected transfer function TF (via the transfer function selector 1974E), and the output of the selected transfer function TF is provided to a gain 1984E and then to an integrator 1985E.
  • a feed-forward correction signal 1967E is provided to the integrator 1985E and is based on the EvsV curve that is selected based on the primary wavelength of the next pulse of the light beam 1160.
  • the feed-forward correction signal 1967E removes, reduces, or rejects energy disturbances.
  • the signal 1967E corrects for the energy differences caused by changing the configuration of the spectral feature selection module 258 and changing Etarget during operation of the optical oscillator 1212E and determines a corrected excitation signal 1968E.
  • the corrected excitation signal 1968E (V(k+1)) is determined based on the following equation: Equation (12), where k is an integer that is greater than or equal to 1 and represents the pulse number of a pulse in the light beam output by the optical oscillator 1212E, l 3 ⁇ 4 is the wavelength of the kth pulse produced by the optical oscillator 1212E, E is an energy value, V is a voltage value, and TF(/.J is one of the transfer functions TF(1), TF(2), ... TF(N) of the optical oscillator 1212E that produced the wavelength in the kth pulse.
  • V* and E* are filtered versions like moving averages of raw voltage and energy values, respectively.
  • an implementation 206 IE of the energy control module 1161E uses a repetitive control approach that relies on energy feed forward to invert or cancel an arbitrary repetitive disturbance (which shows up as a pattern in the energy property signal 2046E), the repetitive disturbance occurring due to intentionally changing the configuration of the spectral feature selection module 258 associated with the optical oscillator 1212E in order to vary the spectral property of the light beam 1160 produced by the optical oscillator 1212E.
  • the energy control module 206 IE includes a target energy generator 2070E (that operates similarly to the target energy generator 1270E), a comparator 2063E, and an energy controller 2072E.
  • the energy controller 2072E requires deductive knowledge of the properties of the arbitrary repetitive disturbance to model the disturbance and make a change to the excitation signal 2068E in bulk (that is for a set number of future pulses).
  • the energy controller 2072E can include a deductive module 2072ED that is configured to obtain this deductive knowledge by, for example, measuring the disturbance on each burst of pulses, and then use this information to develop a model of the disturbance.
  • the energy controller 2072E can also include a correction module 2072EC configured to make a change to the excitation signal 2068E based on the disturbance model.
  • the energy controller 2072E greatly relies on direct observation of these disturbances; therefore, it is important to incorporate the deductive knowledge about the disturbances, including how the disturbances vary or change. For example, if it is known that a disturbance varies significantly with the repetition rate of the pulses of the light beam 1160, then it may be useful to ensure that the deductive module accounts for this dependency.
  • the deductive module 2072ED within the energy controller 2072E can acquire the energy property signal 2046E for a certain period of time, for example, for a set number of pulses in a burst of the light beam 1160 (called the disturbance period). Then, the deductive module 2072ED can compare each of these energy property signals 2046E to the target energy Etarget 207 IE to thereby generate an energy error (which is a part of the energy signal 2066E) for each pulse in disturbance period. The deductive module 2072ED can compute how much of this energy error other feedback controllers within the energy controller 2072E are estimated to have removed, and this is added back to the measured energy error to obtain the total error.
  • the other feedback controllers can include controllers that are discussed herein.
  • the deductive module 2072ED updates a magnitude and alternatively a sign of the disturbance, and the error passes through an integrator (within the deductive module 2072ED) with a gain that is less than one to yield a disturbance shape that is to be inverted.
  • the correction module 2072EC adds the latest disturbance shape to the excitation signal 2068E. This technique is repeated for each disturbance period, and results in training of the feed forward control.
  • a procedure 2100 is performed by the photolithography system 1100.
  • the procedure 2100 determines a corrected input signal (the excitation signal 1168E) for application to the optical source 1105, and specifically to the optical oscillator 1212E.
  • the procedure 2100 is implemented at least in part by the control system 1150, including the energy control module 1161E.
  • the control system 1150 and/or parts of the control system 1150 such as the energy control module 1161E can be implemented as a part of the optical source 1105, as a part of the lithography exposure apparatus 1169, or separate from (but in communication with) both the optical source 1105 and/or the lithography exposure apparatus 1169.
  • a plurality of sets of pulses of the light beam 1160 are produced (2105).
  • the optical source 1105 produces the light beam 1160 such that each pulse in the light beam 1160 is associated with a distinct primary wavelength lr and possibly also a distinct target energy Etarget.
  • the distinct primary wavelength lr is determined based on the configuration of the spectral feature selection module 258.
  • a measurement of an energy of a prior pulse of the light beam 1160 is received (2110).
  • the control system 1150 (and specifically the energy control module 116 IE) receives the energy property signal 1146E from the detection system 1145E for the kth pulse (which can be considered the prior pulse).
  • An energy error of the prior pulse is determined (2115).
  • the error signal 1266E is output from the comparator 1263E, or, with reference to Fig. 16, the error signal 1666E_1 is output from the comparator 1663E_1.
  • the comparator (such as 1263E or 1663E_2) compares the measured energy of the prior light beam pulse (determined from the energy property signal 1146E) to the second target energy Etarget2, since the second target energy Etarget2 is associated with the second set of pulses.
  • the comparator (such as 1263E or 1663E_1) compares the measured energy of the prior light beam pulse (determined from the energy property signal 1146E) to the first target energy Etargetl, since the first target energy Etargetl is associated with the first set of pulses.
  • At least one component of the optical source 1105 is adjusted to thereby adjust, based on the determined error (2115), the energy of the subsequent pulse of the light beam 1160 (2120).
  • the subsequent pulse that is adjusted has a primary wavelength that is the same as the primary wavelength of the prior pulse.
  • the spectral feature selection module 258 is configured to alternate between produce a pulse with a first primary wavelength lr ⁇ and producing a pulse with a second primary wavelength lr2 (such as shown in Figs. 7 and 8A), and the prior pulse (which is the kth pulse) has the first primary wavelength lr ⁇ , then the k+2x pulse (where x is a positive integer) is adjusted because the k+2x pulse also has the first primary wavelength lr ⁇ .
  • the corrected excitation signal 1168E is applied to the optical oscillator 1212E.
  • the voltage to the electrodes 217-a, 217-b is adjusted based on this corrected excitation signal 1168E.
  • a method for controlling an energy of a pulsed light beam comprising: producing a plurality of intermingled sets of pulses of the light beam from an optical source, each set of light beam pulses associated with a distinct primary wavelength and a distinct target energy; receiving a measurement of an energy of a prior pulse of the light beam; determining an energy error including: comparing the measured energy of the prior light beam pulse to a particular target energy associated with a particular set of light beam pulses if the prior light beam pulse is in the particular set of light beam pulses; and adjusting at least one component of the optical source to thereby adjust, based on the determined energy error, the energy of a subsequent pulse in the particular set of light beam pulses.
  • adjusting at least one component of the optical source comprises changing a voltage provided to electrodes associated with an optical oscillator of the optical source.
  • a system comprising: an optical source apparatus comprising: an optical oscillator configured to produce a pulse of light in response to an excitation signal, the pulse of light having a spectral property; and a spectral adjustment apparatus configured to control the spectral property of the pulse of light; and an energy control apparatus communicating with the optical source apparatus, the energy control apparatus configured to: determine a target energy associated with the spectral property of the produced pulse of light; and determine, based at least on the determined target energy, an adjustment to the excitation signal that causes the optical oscillator to produce one or more subsequent pulses of light to account for a change in a configuration of the spectral adjustment apparatus.
  • optical oscillator is associated with a plurality of transfer functions, each transfer function being associated with a particular configuration of the spectral adjustment apparatus and a particular value of the spectral property; and the energy control apparatus is configured to determine the adjustment to the excitation signal based on the transfer function associated with the particular configuration of the spectral adjustment apparatus used to produce the one or more subsequent pulses of light.
  • the spectral adjustment apparatus comprises at least one prism and a diffractive element arranged in optical communication with each other, and each transfer function is associated with a different state of at least one prism.
  • the energy control apparatus is configured to determine the adjustment to the excitation signal that causes the optical oscillator to produce the one or more subsequent pulses of light by determining the adjustment to the excitation signal that causes the optical oscillator to produce one or more subsequent pulses of light associated with the spectral property of the produced pulse of light.
  • the energy control apparatus is configured to determine the target energy associated with the spectral property of the produced pulse of light by receiving a communication from a lithography exposure apparatus that is configured to receive the light pulse, the communication providing a set of target energies, each target energy in the set being associated with a spectral property.
  • An energy control apparatus comprising: a control module configured to: receive an energy value of a prior light pulse emitted from an optical source; perform a comparison including: comparing the received energy value with a first target energy only if the prior light pulse is in a first set of light beam pulses associated with a first primary wavelength; or comparing the received energy value with a second target energy that is distinct from the first target energy only if the prior light pulse is in a second set of light beam pulses associated with a second primary wavelength that is distinct from the first primary wavelength; and adjust, based on the comparison, at least one component of the optical source to thereby adjust the energy of a subsequent light pulse having the primary wavelength associated with the prior light pulse.
  • control module comprises a category module configured to categorize whether the prior light pulse is in the first set of light beam pulses or in the second set of light beam pulses.
  • control module comprises a comparator configured to determine whether the prior light pulse is in the first set of light beam pulses or the second set of light beam pulses, and to provide the first target energy or the second target energy based on the determination.
  • control module comprises a signal module configured to determine the amount of adjustment to be made to the at least one component of the optical source.
  • control module comprise a correction module configured to correct the amount of adjustment to be made to the at least one component of the optical source based on whether the prior light pulse is in the first or the second set of light beam pulses.
  • the filter includes a notch filter that transmits information having a frequency in a first frequency band and substantially blocks information having a frequency outside the first frequency band.
  • the correction module is configured to correct the adjustment amount by applying a feed forward correction to the adjustment amount.
  • the control module being configured to adjust, based on the comparison, at least one component of the optical source to thereby adjust the energy of the subsequent light pulse having the primary wavelength associated with the prior light pulse comprises sending a signal to the optical source to thereby change a voltage provided to electrodes associated with an optical oscillator of the optical source.
  • control module is configured to adjust, based on the comparison, the at least one component of the optical source to thereby adjust the energy of a plurality of subsequent light pulses having the primary wavelength associated with the prior light pulse.
  • control module is configured to maintain, based on the comparison, the energy of a subsequent light pulse that does not have the primary wavelength associated with the prior light pulse.

Abstract

L'invention concerne un procédé de commande d'une énergie d'un faisceau de lumière pulsée. Le procédé consiste : à produire une pluralité d'ensembles entremêlés d'impulsions du faisceau lumineux provenant d'une source optique, chaque ensemble d'impulsions de faisceau lumineux étant associé à une longueur d'onde principale distincte et à une énergie cible distincte ; à recevoir une mesure d'une énergie d'une impulsion précédente du faisceau lumineux ; à déterminer une erreur d'énergie comprenant : la comparaison de l'énergie mesurée de l'impulsion de faisceau lumineux antérieure à une énergie cible particulière associée à un ensemble particulier d'impulsions de faisceau lumineux si l'impulsion de faisceau lumineux antérieure est dans l'ensemble particulier d'impulsions de faisceau lumineux ; et à régler au moins une composante de la source optique de manière à régler ainsi, en fonction de l'erreur d'énergie déterminée, l'énergie d'une impulsion ultérieure dans l'ensemble particulier d'impulsions de faisceau lumineux.
PCT/US2022/022022 2021-04-19 2022-03-25 Formation de multiples images aériennes en un seul passage d'exposition lithographique WO2022225647A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202280038621.1A CN117441133A (zh) 2021-04-19 2022-03-25 在单个光刻曝光遍次中形成多个空间图像
JP2023560973A JP2024518258A (ja) 2021-04-19 2022-03-25 単一リソグラフィ露光パスにおいて複数の空間像を形成する

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US202163176646P 2021-04-19 2021-04-19
US63/176,646 2021-04-19

Publications (1)

Publication Number Publication Date
WO2022225647A1 true WO2022225647A1 (fr) 2022-10-27

Family

ID=81308156

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2022/022022 WO2022225647A1 (fr) 2021-04-19 2022-03-25 Formation de multiples images aériennes en un seul passage d'exposition lithographique

Country Status (4)

Country Link
JP (1) JP2024518258A (fr)
CN (1) CN117441133A (fr)
TW (1) TW202307578A (fr)
WO (1) WO2022225647A1 (fr)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6192064B1 (en) 1997-07-01 2001-02-20 Cymer, Inc. Narrow band laser with fine wavelength control
US7154928B2 (en) 2004-06-23 2006-12-26 Cymer Inc. Laser output beam wavefront splitter for bandwidth spectrum control
US20080036991A1 (en) * 2006-08-10 2008-02-14 Asml Netherlands B.V. Lithographic apparatus, source, source controller and control method
US8144739B2 (en) 2008-10-24 2012-03-27 Cymer, Inc. System method and apparatus for selecting and controlling light source bandwidth
US20130215916A1 (en) * 2011-08-24 2013-08-22 Gigaphoton Inc. Laser apparatus
WO2016164157A1 (fr) * 2015-04-08 2016-10-13 Cymer, Llc (A Nevada Company) Stabilisation de longueur d'onde pour source optique
US20170115575A1 (en) * 2015-10-27 2017-04-27 Cymer, Llc Controller for an optical system

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6192064B1 (en) 1997-07-01 2001-02-20 Cymer, Inc. Narrow band laser with fine wavelength control
US7154928B2 (en) 2004-06-23 2006-12-26 Cymer Inc. Laser output beam wavefront splitter for bandwidth spectrum control
US20080036991A1 (en) * 2006-08-10 2008-02-14 Asml Netherlands B.V. Lithographic apparatus, source, source controller and control method
US8144739B2 (en) 2008-10-24 2012-03-27 Cymer, Inc. System method and apparatus for selecting and controlling light source bandwidth
US20130215916A1 (en) * 2011-08-24 2013-08-22 Gigaphoton Inc. Laser apparatus
WO2016164157A1 (fr) * 2015-04-08 2016-10-13 Cymer, Llc (A Nevada Company) Stabilisation de longueur d'onde pour source optique
US20170115575A1 (en) * 2015-10-27 2017-04-27 Cymer, Llc Controller for an optical system

Also Published As

Publication number Publication date
TW202307578A (zh) 2023-02-16
JP2024518258A (ja) 2024-05-01
CN117441133A (zh) 2024-01-23

Similar Documents

Publication Publication Date Title
US20230152707A1 (en) Forming multiple aerial images in a single lithography exposure pass
US9207119B2 (en) Active spectral control during spectrum synthesis
US8520186B2 (en) Active spectral control of optical source
KR102213686B1 (ko) 펄스형 광 빔의 스펙트럼 특성의 제어 기술
WO2022225647A1 (fr) Formation de multiples images aériennes en un seul passage d'exposition lithographique
TWI830501B (zh) 雷射設備及其操作方法
US11947268B2 (en) Energy correction module for an optical source apparatus
CN118011728A (en) Forming multiple aerial images in a single lithographic exposure pass

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22716741

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2023560973

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 22716741

Country of ref document: EP

Kind code of ref document: A1