TW202315462A - Target supply apparatus - Google Patents

Abstract

A system includes: a conduit including an orifice configured to fluidly couple to a reservoir and to emit molten target material; an actuator including at least a first zone and a second zone that is between the first zone and the orifice, where motion of the first zone and the second zone is transferred to an interior of the conduit; and a controller configured to apply a first actuation signal to the first zone and a second actuation signal to the second zone. The second actuation signal has a higher frequency than the first actuation signal.

Description

target provisioning device

The present invention relates to a target provisioning device. Target delivery equipment can be used to generate targets in extreme ultraviolet (EUV) light sources.

Target devices can be used to create streams or jets of fluid material. For example, a nozzle device can be used to generate a target that is converted into a plasma that emits extreme ultraviolet (EUV) light.

EUV light can be, for example, at a wavelength of 100 nanometers (nm) or less (sometimes also referred to as soft x-rays) and includes wavelengths of, for example, 20 nm or less, between 5 and 20 nm, or between 13 and 14 nm Electromagnetic radiation of light in between can be used in photolithography processes to create extremely small features in a substrate (eg, a silicon wafer) by initiating polymerization in a resist layer. Methods to generate EUV light include, but are not necessarily limited to, converting materials including elements such as xenon, lithium, or tin into a plasmonic state with emission lines in the EUV range. In one such method, often referred to as laser-produced plasma (LPP), laser radiation can be obtained by irradiating, for example, material droplets, slabs, strips, streams, or Target material in the form of clusters to generate the desired plasma. For this process, the plasma is typically generated in a sealed container, such as a vacuum chamber, and various types of metrology equipment are used to monitor the plasma.

In one aspect, a system includes: a conduit including an orifice configured to be fluidly coupled to a reservoir and emit molten target material; an actuator including at least a first section and located at the a second zone between the first zone and the orifice, wherein motion of the first zone and the second zone is transmitted to an interior of the conduit; and a controller configured to transmit a first zone An actuation signal is applied to the first partition and a second actuation signal is applied to the second partition. The second actuation signal has a higher frequency than the first actuation signal.

Implementations can include one or more of the following features.

The second partition can be smaller than the first partition.

The system may also include a plurality of actuator electrodes. In such implementations, at least one actuator electrode can be associated with each of the first partition and the second partition; each of the first actuation signal and the second actuation signal can be includes an electrical signal having a frequency spectrum; and, in order to apply a specific actuation signal to a specific zone of the actuator, the controller can be configured to apply an electrical signal to the the actuator electrodes. The frequency spectrum of at least one electrical signal may comprise more than one frequency.

The actuator may comprise a single piece of material mounted to an exterior of the catheter; the actuator electrodes may be located on an exterior of the actuator, and the actuator electrodes may be spatially separated from each other. In some implementations, the actuator includes a sleeve comprising: a first end; a second end; an inner wall extending from the first end to the second end and mechanically coupled to the the exterior of the conduit; the second end is closer to the orifice than the first end; the first section of the actuator is a first portion of the sleeve, and the second section of the actuator is the a second portion of the sleeve; and at least one surface feature is formed on the exterior of the actuator between the first subregion and the second subregion, and each surface feature is configured to be in the first subregion Partial mechanical isolation is provided from the second partition. The at least one surface feature may include at least one groove recessed into the exterior surface. The at least one surface feature can include a plurality of grooves; each groove can surround the sleeve; and each groove can have a groove shape.

The system can also include a ground electrode located on the first end and the inner wall of the sleeve. One of the plurality of grooves is located between the ground electrode and the first partition. In some implementations, at least one of the plurality of grooves has a different shape than at least one other groove. The outer wall of the sleeve may have a smaller diameter at the second end than at the first end. In some implementations, each actuator electrode surrounds an associated partition. Additionally, in some implementations, a minimum frequency in the spectrum of the second actuation signal is greater than a maximum frequency in the spectrum of the first actuation signal. A maximum frequency in the second spectrum may be greater than a maximum frequency in the first spectrum.

The controller being configured to apply the first actuation signal and the second actuation signal may include the controller being configured to control an electrical signal generator such that the first actuation signal and the second actuation signal are generated The active signal is applied to the respective first partition and the second partition. Each of the first actuation signal and the second actuation signal may include at least one sine wave.

The system may also include the electrical signal generator.

The molten target material can emit EUV light when in a plasma state.

The first section of the actuator may include a first actuator and the second actuator may be different from the first actuator. The system can also include a diaphragm in mechanical communication with an interior of the conduit; and the second actuator can be mechanically coupled to the diaphragm. The system can include a motion transfer block between the first actuator and the second actuator. The first actuator may comprise a stack of actuating elements.

In another aspect, a method includes: fluidly coupling an orifice of a conduit to a reservoir holding molten target material; applying pressure to the reservoir such that the molten target material flows in the conduit ; applying a first actuation signal to a first section of an actuator mechanically coupled to the catheter, the first actuation signal having a first frequency spectrum; and applying a second actuation signal to the actuation One of the drives is the second partition. The second actuation signal has a second frequency spectrum, and the second frequency spectrum includes higher frequencies than the first frequency spectrum.

Implementations can include one or more of the following features.

A third actuation signal can be applied to a third subsection of the actuator, the third actuation signal having a third frequency spectrum.

In another aspect, a system includes: a conduit including an orifice configured to be fluidly coupled to a reservoir and emit molten target material; a one-piece actuator mechanically coupled to The catheter, the one-piece actuator comprising a plurality of individually controllable sections; and a controller configured to apply an individual actuation signal to each of at least a first section and a second section By.

In some implementations, a groove is formed in an exterior surface of the one-piece actuator between the first section and the second section, and the groove is configured to partially mechanically decouple the first section. the first partition and the second partition.

In another aspect, a system includes: a conduit including an orifice configured to be fluidly coupled to a reservoir and emit molten target material; an actuator mechanically coupled to the conduit, the The actuator includes a plurality of individually controllable sections, the plurality of individually controllable sections including at least a first section and a second section, the second section being located between the first section and the orifice; and the second a zone smaller than the first zone; and a controller configured to apply a first actuation signal to the first zone and apply a second actuation signal to the second zone.

The second actuation signal includes at least one frequency greater than all frequencies in the first actuation signal.

In another aspect, the actuator includes: an actuator body including: a ground zone configured to be electrically connected to a reference potential; and a plurality of controllable zones. Each controllable zone is configured to receive a control signal, and in operative use, the controllable zones are configured to be mechanically coupled to a conduit such that movement of the controllable zones is within one of the conduits A pressure wave is generated in the area.

Implementations can include one or more of the following features. The actuator body may comprise a single piece of material; the grounded zone and the plurality of controllable zones are part of the single piece of material; and the single piece of material may be a plurality of spatial features; and the grounded zone may be controlled by a plurality of One of the spatial characteristics is separated from the plurality of controllable partitions, and each controllable partition is separated from a closest controllable partition by one of the plurality of spatial characteristics.

At least one of the controllable zones may be a separate piece of material that does not directly contact any of the other controllable zones or the ground zone.

The actuator body can include a substantially cylindrical sidewall configured to surround one of the conduits.

Implementations of any of the techniques described above may include: EUV light sources, target delivery systems, methods, programs, controllers, or control systems, devices, or devices that act on actuators or target delivery devices. The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings and from the claims.

Referring to FIG. 1 , a block diagram of an EUV light source 100 including a supply system 110 is shown. Supply system 110 emits stream 121 of targets such that targets 121 p are delivered to plasma formation location 123 in vacuum chamber 109 . Target 121p includes a target material, which is any material that emits EUV light 197 when in a plasma state. For example, target materials may include water, tin, lithium, and/or xenon. Plasma formation location 123 receives light beam 106 . Light beam 106 is generated by optical source 105 and delivered to vacuum chamber 109 via optical path 107 . Interaction between light beam 106 and target material in target 121 p produces plasma 196 that emits EUV light 197 .

The supply system 110 includes a conduit 114 defining an orifice 119 . Conduit 114 is mounted to supply system 110 by a nozzle mount or housing 117 . The interior of conduit 114 and orifice 119 are fluidly coupled to reservoir 112 which holds the target material under pressure P. When the pressure P exceeds the pressure in the vacuum chamber 109 , the target material flows into the conduit 114 and exits the orifice 119 as a jet or continuous stream 124 of the target material. The jet 124 of the target material breaks up into individual droplets which coalesce into a stream 121 of larger droplets reaching the plasma formation site 123 . Conduit 114 is coupled to actuator 193 controlled by controller 190 . The motion of the actuator 193 is transmitted to the conduit 114 to generate sound waves inside the conduit 114 .

Controller 190 may include, for example, electronic processing modules, electronic storage, and/or functions or signal generators that generate control signals. In some implementations, the controller 190 controls a separate device, such as a voltage or current source, to generate the control signal applied to the actuator 192 . For example, controller 190 may control a voltage source to generate a control signal in the form of a voltage and/or current signal having a particular amplitude, frequency and/or phase value.

Controller 190 controls the characteristics (eg, amplitude and/or frequency) of the motion of actuator 193 , and thus also controls the characteristics of the acoustic waves inside conduit 114 . The rate at which larger coalesced droplets reach the plasma formation site 123 is determined by the properties of the acoustic waves inside the conduit 114 . Thus, by controlling the actuation of conduit 114 , controller 190 is also configured to control the properties of the droplets in stream 121 . The final target may be generated, eg, at a frequency between 40 and 300 kHz, and may travel towards the plasma formation location 123, eg, at a velocity between 40 and 120 meters per second (m/s), or as high as 500 m/s. The spatial separation between two adjacent objects in the stream of objects 121 may be, for example, between 1 and 3 millimeters (mm). From 50 to 300 initial droplets (also known as Rayleigh droplets) can coalesce to form a single larger target.

The actuator 193 has two or more sections that are individually controlled by the controller 190 . As discussed below, having two or more individually controllable zones improves the performance of the actuator 193 and supply system 110 .

In the example of FIG. 1, the actuator 193 includes a first section 194a and a second section 194b. The second section 194b is between the aperture 119 and the first section 194a. In the example of FIG. 1 , the second partition 194a is relatively close to the aperture 119 and the first partition 194a is further away from the aperture 119 . Each partition 194a and 194b receives a respective control signal 192a and 192b from the controller 190 .

The control signals 192a and 192b have different characteristics. For example, each of the control signals 192a and 192b may be a voltage signal having different frequency bands. In some implementations, the control signal 192a includes a plurality of sinusoidal voltage signals having a frequency between 50 kilohertz (kHz) and 1 megahertz (MHz), and the control signal 192b includes a sinusoidal voltage signal having a frequency between 1 MHz and 20 MHz. A complex number of sinusoidal voltage signals with frequencies between. Other implementations are possible. For example, each control signal 192a and 192b can be a square wave or a triangle wave. The control signals 192a and 192b are periodic with a frequency at which the coalescence target reaches the plasma formation location 123 . That is, the control signals 192a and 192b have a periodicity equal to the frequency at which coalescence targets arrive at the plasma formation location 123 . For example, each of control signals 192a and 192b may be an electrical signal having a frequency spectrum that includes only the fundamental frequency (the frequency at which the target arrives at position 12) and harmonics of the fundamental frequency. Controller 190 may be implemented as more than one single controller or may control separate functions or signal generators. In such implementations, the signals 192a and 192b are synchronized to the same clock to avoid phase drift between the signals 192a and 192b.

Using two or more controllable partitions (in this example, partitions 194a and 194b ) improves the performance and availability of provisioning system 110 . For example, driving various partitions of actuator 193 with different control signals increases the bandwidth over which actuator 193 can be driven compared to driving actuator 193 with a single control signal. In methods where the actuator 193 lacks two or more individually controllable partitions, the actuator 193 is driven with a single control signal having a relatively large bandwidth (eg, 50 kHz to 20 MHz). A single control signal can be amplified, however, amplifiers have a finite gain bandwidth characteristic, where the gain of the amplifier decreases as the bandwidth of the signal to be amplified increases. Therefore, it is relatively challenging to adequately amplify all frequencies in a single control signal. On the other hand, each of the control signals 192a and 192b may be amplified by a separate amplifier. Thus, greater amplification of control signals 192a and 192b is possible.

Furthermore, to increase the amount of EUV light 197 produced, the pressure P is increased, the droplets in the stream 121 are spaced farther apart from each other, and the velocity of the jet 124 is increased by increasing the bandwidth of the drive actuator 193 . For example, for a pressure P of 275 bar, the bandwidth of the control signal is 50 kHz to 5 MHz. However, at a pressure P of 1400 bar, the bandwidth of the control signal is 100 kHz to 20 MHz. In supply system 110, the relatively large bandwidth for a pressure P of 1400 bar is split between partitions 194a and 194b, rather than being applied to conduit 114 with a single control signal. Driving each partition 194a and 194b with a separate control signal 192a and 192b allows the actuator 193 to be efficiently and effectively driven over a wider frequency range and using simpler electronics.

Additionally, while partitions 194a and 194b may be mechanically coupled, partitions 194a and 194b are spatially distinct. This configuration allows certain frequency bands to be delivered to specific portions of the actuator 193 and allows for greater control over the formation of the stream 122 and also allows for more efficient use of the actuator 193 .

Furthermore, in some implementations, the partitions 194a and 194b are different shapes and/or sizes. For example, the actuator 193 may be a ceramic material such as lead zirconate titanate (PZT). When driving such materials at high frequency (eg, 10 MHz) or higher, the current required to obtain the same charge on the PZT increases. Larger current requirements can become a problem if the piezoelectric drive electronics cannot provide that current. The current required to drive a PZT is given by I = C*dV/dt, and dV/dt increases with frequency. Therefore, the current required to drive the PZT increases with frequency. The capacitance of PZT depends on its thickness and area. The capacitance (C) of a PZT in farads is given by C = (1500 x free space permittivity x width x length)/thickness.

On the other hand, at low frequencies, less current is required. By using separate partitions 194a and 194b, actuator 193 can be configured such that partitions 194a and 194b are different sizes to address challenges presented by the frequency characteristics of the actuator 193 material. For example, partition 194a can be a relatively large PZT, and partition 194b can be a relatively small PZT. Larger partitions 194a are driven at relatively low frequencies and create large volume fluctuations in the target material inside conduit 114 .

Therefore, by fabricating partition 194b as a relatively small PZT, the capacitance of the PZT is small and the amount of current required to drive the PZT at high frequencies is reduced. In this way, the actuator 193 can be effectively and efficiently driven at a variety of frequencies. For example, driving partition 194b at a different frequency than partition 194a can result in twice the amount of actuation at the frequency in control signal 192a (due to the ability to amplify low frequency signals relatively easily) and 10 times the amount at the frequency in control signal 192b Actuation amount (reduction due to capacitance).

The configuration shown in Figure 1 is an example, and other implementations are possible. For example, conduit 114 may be a capillary, such as capillary 214 shown in FIGS. 2 , 3 and 4 . In such implementations, a nozzle housing or mount 117 attaches the capillary to the vacuum chamber 109 and fluidly couples the capillary to the reservoir 112 . In such implementations, the conduit 114 extends from the nozzle mount or housing 117 and need not be received within the mount or housing 117 . In the example shown in FIG. 1 , the conduit extends substantially along the X direction. However, in some implementations, conduit 114 has a more complex path and extends in more than one direction. The figure shows catheter 514 with a more complex path.

Figure 2A is a side cross-sectional block diagram of the target forming apparatus 216 in the X-Z plane. 2B is a cross-sectional view of the target forming apparatus 216 in the Y-Z plane taken along line 2B'-2B' of FIG. 2A. Target forming device 216 may be used in EUV light source 100 (FIG. 1). Target forming device 216 includes a capillary 214 . The capillary 214 includes a side wall 230 extending from a first end 231 to a second end 232 along the X direction. Sidewall 230 is a three-dimensional object that is generally cylindrical. Sidewall 230 may be made of, for example, glass or quartz.

The sidewall 230 includes an inner surface 233 and an outer surface 239 . The inner surface 233 defines an inner region 238 in fluid communication with a nozzle 235 at the first end 231 . The nozzle 235 narrows along the -X direction to define an orifice 219 . In operative use, the inner region 238 is fluidly coupled to a reservoir of target material, such as reservoir 112 of FIG. 1 , and the molten target material flows in the inner region 238 and through the holes in the -X direction Mouth 219.

The outer surface 239 is mechanically coupled to an actuator assembly 293 . The outer surface 239 can be used, for example, with an adhesive (such as a benzophenone resin, a resin containing benzophenone, a bismaleimide resin, a monocyanate resin, or a resin containing cyanate) , with mechanical fasteners, or mechanically coupled to the actuator assembly 293 by direct contact (eg, an interference fit) between the outer surface 239 and the actuator assembly 293 .

The actuator assembly 293 includes an actuating body 291 and electrodes 295a, 295b and 295g. Referring also to FIG. 2B , the actuation body 291 is generally cylindrical and includes an inner wall 285 and an outer surface 286 . The inner wall 285 defines a bore surrounding a portion of the outer surface 239 of the capillary 214 .

The actuating body 291 is made of a material capable of moving the side wall 230 . For example, the actuation body 291 may be a piezoelectric ceramic material, such as lead zirconate titanate (PZT), that changes shape in response to the application of a voltage. Movement of the actuation body 291 causes a corresponding displacement of the sidewall 230 by radial contraction and expansion. The radial contraction and expansion cause acoustic or pressure waves in the inner region 238 .

The actuating body 291 has a first partition 294a, a second partition 294b and a ground partition 294g. The first partition 294a and the second partition 294b are individually controllable partitions. The first partition 294a is between the second partition 294b and the ground partition 294g. The second section 294b is the section closest to the orifice 219 . The radial thicknesses of the first partition 294a, the second partition 294b and the ground partition 294g are substantially the same. However, the second section 294b extends a shorter distance along the X direction than the first section 294a. Accordingly, the second partition 294b has a smaller volume of material (eg, PZT) than the first partition 294a.

Electrode 295g is on a portion of outer surface 286 that is adjacent to ground partition 294g. Electrode 295g also runs along edge 284 of actuator body 291 and along inner wall 285 . During operational use of the target forming apparatus 216, the electrode 295g is electrically connected to ground or a reference voltage.

Electrode 295a is on a portion of outer surface 296 adjacent to first segment 294a. Electrode 295b is on a portion of outer surface 296 that is adjacent to second segment 294b. The electrodes 295a, 295b, 295g may be coated on the outer surface 296, attached to the outer surface 296 by mechanical fasteners and/or attached to the outer surface 296 by a conductive adhesive.

Actuation body 291 includes spatial features 288a and 288b on outer surface 286 . Spatial feature 288a provides separation between electrodes 295g and 295a, and spatial feature 288b provides separation between electrodes 295a and 295b. The actuation body 291 is a single piece or collection of material pieces that are joined during use. Therefore, the ground section 294g, the first section 294a, and the second section 294b are mechanically coupled. However, spatial feature 288a provides partial mechanical decoupling or partial mechanical isolation between ground partition 294g and first partition 294a, and spatial feature 288b provides partial mechanical decoupling or partial mechanical isolation between first partition 294a and second partition 294b. isolation.

In the example shown, spatial features 288a and 288b are indentations formed on outer surface 286 . Notches 288 a and 288 b have a semicircular cross-section and surround outer surface 286 . In other words, in the example of FIG. 2A , notches 288 a and 288 b are recessed rings surrounding actuation body 291 . However, spatial features 288a and 288b may take any form that provides partial mechanical isolation between adjacent partitions. For example, spatial features 288a and 288b may be indentations having triangular, rectangular, square, or irregular cross-sections rather than semi-circular cross-sections. Additionally, spatial features 288a and 288b may protrude from outer surface 296 rather than be recessed into outer surface 296 . Additionally, spatial features 288a and 299b may extend less than the entire circumference of actuation body 291 . In some implementations, such as shown in FIG. 3 , spatial features 288a and 288b do not have the same size and do not have the same spatial characteristics.

In operative use, the controller 190 (FIG. 1) provides a first control signal 192a to the first electrode 295a, causing the first segment 294a to move in accordance with the first control signal 192a. For example, the first control signal 192a may comprise a sinusoidal voltage signal having a frequency between 50 KHz and 1 MHz, and application of the first control signal 192a causes the first partition 294a to vibrate at these frequencies. The controller 190 provides the second control signal 192b to the second electrode 295b, so that the second partition 294b moves according to the second control signal 192b. For example, the second control signal 192b may include a sinusoidal voltage signal having a frequency between 1 MHz and 20 MHz, and application of the second control signal 192b causes the second partition 294b to vibrate at these frequencies.

Because the first partition 294a is not completely mechanically isolated from the second partition 294b, some frequencies applied to the first partition 294a propagate to the second partition 294b, and vice versa. However, the spatial features 288b reduce such crosstalk such that the first partition 294a vibrates primarily due to the application of the first control signal 192a and the second partition 294b vibrates primarily due to the application of the second control signal 192b. Thus, the target forming apparatus 216 includes two separately controllable sections (sections 294a and 294b), and the characteristics of the control signal applied to each section can be varied to make the movement of the actuator body 291 more finely controllable. Vibration of partitions 294a and 294b generates corresponding pressure or acoustic waves in the target material in inner region 238 to promote droplet formation at a frequency and size appropriate to the application.

Figure 3 is a side sectional block diagram of the target forming apparatus 316 in the X-Z plane. Target forming device 316 may be used in EUV light source 100 to generate stream 122 (FIG. 1). Target forming device 316 includes capillary 214 and actuator assembly 393 . The actuator assembly 393 includes an actuator body 391 and a ground section 394g, a first section 394a, and a second section 394b. The first partition 394a is between the ground partition 394g and the second partition 394b. The actuator body 391 includes an outer surface 386 and an inner wall 385 . Actuator body 391 also includes spatial features 388 a and 388 b on outer surface 386 .

Actuator assembly 393 is similar to actuator assembly 293 except that spatial features 388a and 388b are not the same size and shape. Spatial features 388a are indentations in outer surface 386 . Spatial feature 388a has a semicircular cross-section and surrounds actuator body 391 . Spatial feature 388b is also a recess in outer surface 386, but spatial feature 388b extends further into outer surface 386 than spatial feature 388a and has a different cross-sectional shape. The spatial feature 388b has an asymmetrically arcuate cross section with a first side 381a and a second side 381b. The first side 381a and the second side 381a are curves or arcs that form a larger arc that defines the spatial feature 388b.

The first side 381a extends further from the inner wall 385 than the second side 381b. Accordingly, the first section 394a has a thicker radial dimension than the second section 394b. The second partition 394b has a smaller extent in the X direction, and thus has a smaller volume than the first partition 394b. Because spatial feature 388b extends deeper into outer surface 386 , first section 394a and second section 394b are connected by a relatively thinner portion of actuator body 291 . Spatial feature 388b provides more mechanical separation between adjacent partitions than spatial feature 288b (FIG. 2A) and spatial feature 388a. Thus, although the first section 394a is physically connected to the second section 394b, the spatial feature 388b provides additional mechanical isolation and mechanical separation such that the first section 394a is more mechanically separated from the second section 394b than the first section 294a is from the second section 294b. .

In operative use, the ground electrode 395g (which is on a portion of the outer surface 386 adjacent to the ground partition 394g), the edge 384 and the inner wall 385 are electrically connected to ground or a reference potential. Electrode 395a is on a portion of outer surface 386 that is adjacent to first segment 394a. Electrode 395b is on a portion of outer surface 386 that is adjacent to second segment 394b. Electrodes 395a and 395b receive control signals 191a and 192b, respectively, from controller 190 (FIG. 1). The relatively small size of the second partition 394b allows the second partition 394b to be efficiently driven at higher frequencies (eg, 1 to 20 MHz).

Other implementations of actuator assemblies 293 and 393 are possible. For example, actuator assemblies 292 and/or 392 may include more than two individually controllable sections. For example, actuator bodies 291 and/or 391 may include three partitions, four partitions, or more than four partitions associated with electrodes receiving control signals from controller 190 . In other words, actuator assemblies 293 and/or 393 may be configured to be controlled with three, four or more separate frequency bands.

Actuator assemblies 293 and 393 include respective actuator bodies 291 and 391 as a single piece of material. However, in other implementations, the actuator assembly includes a plurality of discrete or distinct actuator bodies. Figures 4, 5 and 7 show examples of such actuator assemblies.

Figure 4 is a side cross-sectional block diagram of the target forming apparatus 416 in the X-Z plane. Target forming device 416 may be used in EUV light source 100 to generate stream 122 (FIG. 1).

Target forming device 416 includes capillary 214 and actuator assembly 493 . The actuator assembly 493 includes a ground section 494g, a first section 494a, and a second section 494b. The first partition 494a is between the ground partition 494g and the second partition 494b. Each of the ground section 494g, first section 494a, and second section 494b is a discrete body of actuation material. For example, each of these partitions can be a ring of PZT material surrounding and mechanically coupled to the outer wall 239 of the capillary 214 . Ground section 494g, first section 494a, and second section 494b are positioned along sidewall 230 such that they do not directly contact each other.

In operative use, a ground electrode 495g on the ground section 494g and running along the outer surface 239 of the sidewall 230 is electrically connected to ground or a reference potential. Electrode 495a is on first segment 494a. Electrode 495b is on second segment 494b. Electrodes 495a and 495b receive control signals 191a and 191b, respectively, from controller 190 (FIG. 1). In the example shown in FIG. 4, the second partition 494b has a smaller volume than the first partition 494a. The relatively small size of the second partition 494b allows the second partition 494b to be efficiently driven at higher frequencies (eg, 1 to 20 MHz).

Other implementations are possible. For example, target forming apparatus 416 may be implemented with ground partition 494g and first partition 494a on a single piece of material and partially mechanically isolated by a spatial feature such as spatial feature 388a. In such implementations, the second section 494b is a separate piece of material and does not directly touch the first section 494a or the ground section 494g. Furthermore, although object forming apparatus 416 is shown as having two partitions (first partition 494a and second partition 494b) receiving control signals from controller 190, object forming apparatus 416 may implement a configuration configured to receive control signals from controller 190 ( or another controller) to receive control signals for additional partitions.

Figure 5 is a side cross-sectional block diagram of a target forming apparatus 516 in the X-Z plane. Target forming device 516 may be used in EUV light source 100 to generate stream 122 (FIG. 1). Target forming apparatus 516 includes an actuator assembly 593 and conduit 514 held in a mounting assembly or housing 511 . Housing 511 holds actuator assembly 593 and conduit 514 and may be used to mount target forming apparatus 516 to a vacuum chamber such as chamber 109 of FIG. 1 .

Conduit 514 includes an interior region 538 configured to be fluidly coupled to a reservoir, such as reservoir 112 ( FIG. 1 ). The inner region 538 may be fluidly coupled to the reservoir by a passage (not shown) drilled through the housing 511 or otherwise formed in the housing 511 . Conduit 514 has a substantially T-shape comprising a region 514a extending in the Z direction (and may extend in the Y-Z plane) and a region 514b extending in the X direction. The region 514b narrows towards an aperture 519 through which the target material can pass. Region 514a is in fluid contact with membrane 512 . Diaphragm 512 is flexible and movable, and movement of diaphragm 512 generates pressure waves in interior region 538 . Membrane 512 may be part of housing 511 , or membrane 512 may be a separate element attached to housing 511 . The housing 511 and the diaphragm 512 can be made of molybdenum, tantalum or tungsten, for example.

The actuator assembly 593 includes a first section 594a and a second section 594b. The first partition 594a and the second partition 594b are shown diagonally hatched. The first segment 594a and the second segment 594b are made of an actuation material such as PZT. The first partition 594a and the second partition 594b are discrete partitions and do not directly touch each other. The first partition 594a and the second partition 594b are three-dimensional objects and may have, for example, a circular, rectangular or square shape in the Y-Z plane. The first and second partitions 594a, 594b may be continuous objects and may not necessarily include openings, holes, or other features that may be used to position either the partition 594a or the partition 594b around another object. The first partition 594a and the second partition 594b may have different shapes in the Y-Z plane. In the example shown in FIG. 5, the second partition 594b has a smaller spatial volume than the first partition 594a.

The actuator assembly 593 includes a positioning mechanism 571 configured to position and retain the first section 594a. The positioning mechanism 571 may include, for example, a pre-tensioned wedge and/or a spacer that holds the first section 594a in place while also allowing the first section 594a to change shape.

The actuator assembly 593 also includes a block 572 between the second section 594b and the first section 594a. Block 572 has a face 572a and a top 572b. Tip 572b extends away from face 572a in the -X direction and is narrower in Z direction than face 572a. Face 572a is in contact with first segment 594a. A second partition 594b is mounted on top 572b. Top end 572b is in contact with diaphragm 512 . Top end 572b is shaped to direct vibrations from the motion of first section 594a to diaphragm 512 .

In operational use, control signals 191a and 191b from controller 190 (FIG. 1) are provided to first and second partitions 494a, 494b, respectively, to control the movement of these partitions. The vibrations of the first section 594a and the second section 594b are transmitted from the top 572b to the diaphragm 512 . Thus, the diaphragm 512 vibrates based on the frequency at which the first segment 594a and the second segment 594b vibrate. Vibration of diaphragm 512 causes corresponding sound waves in interior region 538 .

Actuator assembly 593 may include additional components. For example, actuator assembly 593 may include one or more electrodes on each section 594a and 594b. The actuator assembly 593 may include more than one controllable zone, and thus may include more PZTs than shown in FIG. 5 .

6 is a side cross-sectional block diagram of an actuator assembly 693, which is an example implementation of the actuator assembly 593 in which the first partition 594a is implemented as a stack 694 of PZT disks. Stack 694 may include 10, 50, 100 or more thin PZT disks. The disc may have a circular cross-section in the Y-Z plane. Stack 694 may have a range in the X direction of about 2 millimeters (mm) to 10 mm. Stack 694 may be held together by a compressive force provided by positioning mechanism 571 along the X direction.

Figure 7 is a side cross-sectional block diagram of a target forming apparatus 716 in the X-Z plane. Target forming device 716 may be used in EUV light source 100 to generate stream 122 (FIG. 1). Target forming apparatus 716 includes conduit 714 defining an interior region 738 and an orifice 719 . Conduit 714 is generally conical and narrows toward orifice 719 in the -X direction. Target forming device 716 also includes various mounting elements or housings 711 . Mounting element or housing 711 is used to house the components of target forming apparatus 716 and to mount target forming apparatus 516 to a vacuum chamber such as vacuum chamber 109 .

Target forming apparatus 716 also includes partitions 794 a and 794 b , each of which is a ring of PZT material mounted to outer surface 733 of conduit 714 . Section 794a has a larger radius and greater longitudinal thickness than section 794b. Accordingly, partition 794b has a smaller spatial volume than partition 794b. Of the partitions 794 a and 794 b , the partition 794 b is closer to the aperture 719 .

In operational use, control signals 191a and 191b from controller 190 (FIG. 1) are provided to leads 777 and 778, respectively. Leads 777 and 778 may be wires or cables. Leads 777 are electrically connected to electrodes (not shown) on the first segment 794a, and leads 778 are electrically connected to electrodes (not shown) on the second segment 794b. Control signals 191a and 191b control the movement of partitions 794a and 794b, respectively. The vibrations of the first partition 794 a and the second partition 794 b are transmitted to the interior space 738 and generate sound waves in the interior region 538 .

Any of the target forming apparatuses 216, 316, 416, 516, and 716 discussed above may be used in an EUV light source. Referring to Figure 8, an implementation of an LPP EUV light source 800 is shown. Any of the nozzle assemblies discussed above may be used in light source 800 as part of supply system 825 .

LPP EUV light source 800 is formed by irradiating target mixture 814 at plasma formation location 805 with an amplified beam 810 that travels along a beam path toward target mixture 814 . The target material discussed with respect to FIG. 1 and the target in stream 121 discussed with respect to FIG. 1 may be or include a target mixture 814 . The plasma formation location 805 is within the interior 807 of the vacuum chamber 830 . When the amplified light beam 810 is shone on the target mixture 814, the target material within the target mixture 814 is converted into a plasmonic state of an element having an emission line in the EUV range. The generated plasma has certain characteristics depending on the composition of the target material within the target mixture 814 . Such characteristics may include the wavelength of EUV light generated by the plasma and the type and amount of debris released from the plasma.

The light source 800 also includes a supply system 825 that delivers, controls, and directs a target in the form of a droplet, a stream, a solid particle or cluster, a solid particle contained within a droplet, or a solid particle contained within a stream Mixture 814. Target mixture 814 includes a target material such as water, tin, lithium, xenon, or any material that has an emission line in the EUV range when converted to a plasma state. For example, elemental tin can be used as pure tin (Sn); as tin compounds such as SnBr ₄ , SnBr ₂ , SnH ₄ ; as tin alloys such as tin-gallium alloys, tin-indium alloys, tin-indium- Gallium alloys or any combination of these alloys. Target mixture 814 may also include impurities such as non-target particles. Thus, target mixture 814 is made only of the target material in the absence of impurities. Target mixture 814 is delivered by supply system 825 into interior 807 of chamber 830 and to plasma formation location 805 .

Light source 800 includes a driven laser system 815 that produces an amplified beam 810 due to population inversion within one or more gain media of laser system 815 . Light source 800 includes a beam delivery system including beam delivery system 820 and focusing assembly 822 between laser system 815 and plasma formation location 805 . Beam delivery system 820 receives amplified beam 810 from laser system 815 , and steers and adjusts amplified beam 810 as necessary and outputs amplified beam 810 to focusing assembly 822 . Focusing assembly 822 receives amplified beam 810 and focuses beam 810 to plasma formation location 805 .

In some implementations, laser system 815 may include one or more optical amplifiers, lasers, and/or lamps for providing one or more main pulses and, in some cases, one or more pre-pulses. Each optical amplifier includes a gain medium capable of optically amplifying a desired wavelength with high gain, an excitation source, and internal optics. The optical amplifier may or may not have a laser mirror or other feedback device forming the laser cavity. Thus, laser system 815 produces amplified beam 810 even in the absence of a laser cavity due to population inversion in the gain medium of the laser amplifier. Furthermore, the laser system 815 can produce the amplified beam 810 as a coherent laser beam in the presence of a laser cavity to provide sufficient feedback to the laser system 815 . The term "amplified light beam" encompasses one or more of: light from laser system 815 that is only amplified, but not necessarily coherent laser oscillations, and light from laser system 815 that is also amplified and also coherent laser oscillations of light.

The optical amplifier in laser system 815 may include a gas fill (including _CO2 ) as a gain medium and may amplify wavelengths between about 9100 nm and about 11000 nm, and especially at about 10600 nm, with a gain of greater than or equal to 800 times of light. Suitable amplifiers and lasers for use in laser system 815 may include pulsed laser devices, such as pulsed gas discharge _CO2 laser devices, such as those used in relatively high power ₍ DC or RF excitation operated at eg 10 kW or higher) and high pulse repetition rate (eg 40 kHz or greater) produces radiation at about 9300 nm or about 10600 nm. The pulse repetition rate may be, for example, 50 kHz. The optical amplifiers in the laser system 815 may also include a cooling system, such as water, that may be used when operating the laser system 815 at higher powers.

Light source 800 includes collector mirror 835 with aperture 840 to allow amplified light beam 810 to pass through and to plasma formation location 805 . Collector mirror 835 can be, for example, an ellipsoidal mirror with a primary focus at plasma formation location 805 and a secondary focus (also referred to as intermediate focus) at intermediate location 845, where EUV light can be output from light source 800 and can be The EUV light is input to, for example, an integrated circuit lithography tool (not shown). The light source 800 may also include an open-ended hollow conical shield 850 (e.g., a gas cone) that tapers from the collector mirror 835 toward the plasma formation location 805 to reduce entry into the focusing assembly 822 and/or The amount of plasma generated debris of the beam delivery system 820 while allowing the amplified beam 810 to reach the plasma formation location 805 . For this purpose, a gas flow may be provided in the shroud which is directed to the plasma formation location 805 .

The light source 800 may also include a master controller 855 connected to a droplet position detection feedback system 856 , a laser control system 857 and a beam control system 858 . The light source 800 may include one or more target or droplet imagers 860 that provide an output indicative of the location of the droplet, for example, relative to the plasma formation location 805 and provide this output to the droplet position detection feedback system 856, which The drop position detection feedback system 856 can, for example, calculate a droplet location and trajectory from which a droplet location error can be calculated on a droplet-by-droplet basis or averaged. The droplet location detection feedback system 856 thus provides the droplet location error as an input to the master controller 855 . Thus, master controller 855 may provide, for example, a laser position, direction, and timing correction signal to laser control system 857, which may be used, for example, to control laser timing circuits and/or to beam control system 858, which beam control system 858 is used to control the positioning of the amplified beam and the shaping of the beam delivery system 820 to change the position and/or focus of the focused spot of the beam within the chamber 830 .

The supply system 825 includes a target material delivery control system 826 operable to modify the release point of droplets as released by a target material supply device 827 in response to signals, for example, from the master controller 855, to correct for reaching the desired delivery point. Error in the droplet at the slurry formation location 805. The target material supply device 827 may be or include any of the target forming devices and/or any of the actuators discussed above.

In addition, light source 800 may include light source detectors 865 and 870 that measure one or more EUV light parameters, including but not limited to pulse energy, energy distribution as a function of wavelength, energy in a specific wavelength band, specific wavelength band External energy, and angular distribution and/or average power of EUV intensity. The light source detector 865 generates a feedback signal for the master controller 855 to use. Feedback signals may, for example, indicate errors in parameters such as timing and focal length of laser pulses that properly intercept the droplet at the proper place and time for effective and efficient EUV light generation.

The light source 800 may also include a guide laser 875 that may be used to align various segments of the light source 800 or to assist in steering the amplified beam 810 to the plasma formation location 805 . In conjunction with the pilot laser 875 , the light source 800 includes a metrology system 824 placed within the focusing assembly 822 to sample a portion of the light from the pilot laser 875 and the amplified beam 810 . In other implementations, the metrology system 824 is placed within the beam delivery system 820 . The metrology system 824 may include an optical element made of any material that can withstand the power of the steered laser beam and the amplified beam 810 to sample or redirect a subset of light. A beam analysis system is formed by the metrology system 824 and the master controller 855 because the master controller 855 analyzes the light sampled by the homing laser 875 and uses this information to adjust the focus assembly 822 via the beam control system 858 components.

Thus, in summary, the light source 800 produces an amplified beam 810 that is directed along a beam path to irradiate the target mixture 814 at the plasma formation location 805 to convert the target material within the mixture 814 to be emitted at Plasma of light in the EUV range. The amplified beam 810 operates at a specific wavelength (also referred to as a drive laser wavelength) determined based on the design and properties of the laser system 815 . Additionally, the amplified beam 810 can be laser when the target material provides sufficient feedback back into the laser system 815 to produce coherent laser light or where the driving laser system 815 includes suitable optical feedback to form a laser cavity beam.

Embodiments can be further described using the following terms: 1. A system comprising: a conduit comprising an orifice configured to be fluidly coupled to a reservoir and emit molten target material; an actuator comprising at least a first section and a second section located between the first section and the orifice, wherein motion of the first section and the second section is transmitted to an interior of the conduit; and a controller configured to apply a first actuation signal to the first partition and a second actuation signal to the second partition, wherein the second actuation signal has a greater frequency than the first actuation signal One of the higher frequencies of the moving signal. 2. The system of clause 1, wherein the second partition is smaller than the first partition. 3. The system of clause 1, further comprising a plurality of actuator electrodes; and wherein at least one actuator electrode is associated with each of the first partition and the second partition; the first actuating each of the signal and the second actuation signal comprises an electrical signal having a frequency spectrum; and in order to apply a specific actuation signal to a specific partition of the actuator, the controller is configured to apply a An electrical signal is applied to the actuator electrode associated with the particular partition. 4. The system of clause 3, wherein the spectrum of at least one electrical signal comprises more than one frequency. 5. The system of clause 3, wherein the actuator comprises a single piece of material mounted to an exterior of the catheter; the actuator electrodes are located on an exterior of the actuator, and the actuator electrodes spatially separated from each other. 6. The system of clause 5, wherein the actuator comprises a sleeve comprising: a first end; a second end; an inner wall extending from the first end to the second end and mechanically coupled to the exterior of the catheter; the second end is closer to the orifice than the first end; the first section of the actuator is a first portion of the bushing, and the second section of the actuator is a second portion of the bushing; and At least one surface feature is formed on the exterior of the actuator between the first subregion and the second subregion, wherein each surface feature is configured to provide a portion between the first subregion and the second subregion Mechanical isolation. 7. The system of clause 6, wherein the at least one surface feature comprises at least one groove recessed into the outer surface. 8. The system of clause 7, wherein the at least one surface feature comprises a plurality of grooves; each groove surrounds the sleeve; and each groove has a groove shape. 9. The system of clause 8, further comprising a ground electrode located on the first end and the inner wall of the sleeve; and wherein One of the plurality of grooves is located between the ground electrode and the first partition. 10. The system of clause 9, wherein at least one of the plurality of grooves has a different shape compared to at least one other groove. 11. The system of clause 10, wherein the diameter of the outer wall of the sleeve is smaller at the second end than at the first end. 12. The system of clause 3, wherein each actuator electrode surrounds an associated partition. 13. The system of clause 3, wherein a minimum frequency in the spectrum of the second actuation signal is greater than a maximum frequency in the spectrum of the first actuation signal. 14. The system of clause 1, wherein the controller is configured to apply the first actuation signal and the second actuation signal comprises the controller being configured to control an electrical signal generator such that the first actuation signal is generated An actuation signal and the second actuation signal are applied to respective first and second partitions. 15. The system of clause 14, further comprising the electrical signal generator. 16. The system of clause 14, wherein each of the first actuation signal and the second actuation signal comprises at least one sine wave. 17. The system of clause 1, wherein the molten target material emits extreme ultraviolet light when in a plasma state. 18. The system of clause 1, wherein the first partition of the actuators includes a first actuator and the second actuator includes a second actuator different from the first actuator. 19. The system of clause 18, wherein the system further comprises a septum in mechanical communication with an interior of the catheter; and The second actuator is mechanically coupled to the diaphragm. 20. The system of clause 19, further comprising a motion transfer block between the first actuator and the second actuator. 21. The system of clause 20, wherein the first actuator comprises a stack of actuation elements. 22. The system of clause 3, wherein a maximum frequency in the second spectrum is greater than a maximum frequency in the first spectrum. 23. A method comprising: fluidly coupling an orifice of a conduit to a reservoir holding molten target material; applying pressure to the reservoir causing the molten target material to flow in the conduit; applying a first actuation signal to a first section of an actuator mechanically coupled to the catheter, the first actuation signal having a first frequency spectrum; and applying a second actuation signal to a second section of the actuator, wherein the second actuation signal has a second frequency spectrum, and The second spectrum contains higher frequencies than the first spectrum. 24. The method of clause 23, further comprising: A third actuation signal is applied to a third subsection of the actuator, wherein the third actuation signal has a third frequency spectrum. 25. A system comprising: a conduit comprising an orifice configured to be fluidly coupled to a reservoir and emit molten target material; a one-piece actuator mechanically coupled to the catheter, the one-piece actuator comprising a plurality of individually controllable segments; and A controller configured to apply a separate actuation signal to each of at least a first partition and a second partition. 26. The system of clause 25, wherein a groove is formed in an outer surface of the one-piece actuator between the first subregion and the second subregion, and the groove is configured to partially The first partition and the second partition are mechanically decoupled. 27. A system comprising: a conduit comprising an orifice configured to be fluidly coupled to a reservoir and emit molten target material; an actuator mechanically coupled to the catheter, the actuator comprising a plurality of individually controllable segments, wherein The plurality of individually controllable partitions includes at least a first partition and a second partition, the second subregion is located between the first subregion and the orifice; and the second subregion is smaller than the first subregion; and A controller configured to apply a first actuation signal to the first partition and a second actuation signal to the second partition. 28. The system of clause 27, wherein the second actuation signal includes at least one frequency that is greater than all frequencies in the first actuation signal. 29. An actuator comprising: An actuator body comprising: a ground partition configured to be electrically connected to a reference potential; and a plurality of controllable zones, wherein each controllable zone is configured to receive a control signal, and wherein in operative use, the controllable zones are configured to be mechanically coupled to a catheter such that the controllable zones The movement of the pipe generates a pressure wave in an inner region of the catheter. 30. The actuator of clause 29, wherein the actuator body comprises a single piece of material; the grounded partition and the plurality of controllable zones are part of the single piece of material; and the single piece of material comprises a plurality of voids characteristics; and The grounded zone is separated from the plurality of controllable zones by one of the plurality of spatial features, and each controllable zone is separated from a closest controllable zone by one of the plurality of spatial features. 31. The actuator of clause 29, wherein at least one of the controllable zones is a separate piece of material that does not directly contact any of the other controllable zones or the zone. 32. The actuator of clause 29, wherein the actuator body includes a substantially cylindrical sidewall configured to surround the conduit.

The above-mentioned implementation and other implementations are within the scope of the following patent applications.

100:EUV light source 105: Optical source 106: Beam 107: Optical path 109: vacuum chamber 110: Supply system 112: Reservoir 114: Conduit 117: Mounting piece or shell 119: Orifice 121: Streaming 121p: target 123: Plasma formation position 124:Jet 190::controller 192a control signal 192b: Control signal 193: Actuator 194a: First Division 194b: Second partition 196: Plasma 197:EUV light 214: Capillary 216: Target Formation Equipment 219: Orifice 230: side wall 231: first end 232: second end 233: inner surface 235: Nozzle 238: Internal area 239: Outer surface 284: edge 285: inner wall 286: Outer surface 288a: Spatial features/notches 288b: Spatial features/notches 291:Actuate the main body 293: Actuator assembly 294a: First Partition 294b: Second partition 294g: Ground partition 295a: electrode 295b: electrode 295g: electrode 296: Outer surface 316: Target Formation Equipment 381a: First side 381b: second side 384:Edge 385: inner wall 386: Outer surface 388a: Spatial features 388b: Spatial features 391:Actuator body 393: Actuator assembly 394a: First Partition 394b: Second partition 394g: Ground partition 395a: electrode 395b: electrode 395g: Ground electrode 416: Target Formation Equipment 493: Actuator assembly 494a: First Partition 494b: Second partition 494g: Ground partition 495a: electrode 495b: electrode 495g: Ground electrode 511: shell 512: Diaphragm 514: Conduit 514a: area 514b: area 516: target forming equipment 519: orifice 538: Internal area 571: Positioning mechanism 572: block 572a: face 572b: top 593: Actuator assembly 594a: First Partition 594b: Second partition 693: Actuator assembly 694:Stack 711: Mounting elements or enclosures 714: Conduit 716: Target Formation Equipment 719: orifice 733: outer surface 738: Inner area 777:lead 778:lead 794a: partition 794b: partition 800: light source 805: Plasma formation position 807: internal 810: amplified light beam 814: target mixture 815:Laser system 820: beam delivery system 822:Focus assembly 824: Weights and measures system 825:Supply system 826: Target material delivery control system 827: Target material supply equipment 830: vacuum chamber 835: collector mirror 840: porosity 845: middle position 850: Open-ended hollow conical shield 855: Master controller 856: Droplet position detection feedback system 857:Laser control system 858: Beam control system 860: target or droplet imager 865:Light source detector 870:Light source detector 875:Guide Laser 2B'-2B': line X: direction Z: Direction P: pressure

FIG. 1 is a block diagram of an example of an EUV light source. Figure 2A is a side cross-sectional block diagram of an example of a target forming apparatus in the X-Z plane. 2B is a cross-sectional view of the target forming apparatus of FIG. 2A in the Y-Z plane taken along line 2B'-2B'. Fig. 3 is a side sectional block diagram of another example of an object forming apparatus in the X-Z plane. Fig. 4 is a side sectional block diagram of another example of an object forming apparatus in the X-Z plane. Fig. 5 is a side sectional block diagram of another example of an object forming apparatus in the X-Z plane. Figure 6 is a side sectional block diagram of an example of an actuator assembly. Fig. 7 is a side sectional block diagram of another example of an object forming apparatus in the X-Z plane. 8 is a block diagram of an example of an EUV light source.

192a: Control signal

192b: Control signal

214: Capillary

219: Orifice

235: Nozzle

239: Outer surface

416: Target Formation Equipment

493: Actuator assembly

494a: First Partition

494b: Second partition

494g: Ground partition

495a: electrode

495b: electrode

495g: Ground electrode

Claims (32)

A system comprising: a conduit comprising an orifice configured to be fluidly coupled to a reservoir and emit molten target material; an actuator comprising at least a first section and a second section located between the first section and the orifice, wherein motion of the first section and the second section is transmitted to an interior of the conduit; and a controller configured to apply a first actuation signal to the first partition and a second actuation signal to the second partition, wherein the second actuation signal has a greater frequency than the first actuation signal The frequency of the moving signal is one high. The system of claim 1, wherein the second partition is smaller than the first partition. The system of claim 1, further comprising a plurality of actuator electrodes; and wherein at least one actuator electrode is associated with each of the first partition and the second partition; the first actuation signal and Each of the second actuation signals includes an electrical signal having a frequency spectrum; and in order to apply a specific actuation signal to a specific partition of the actuator, the controller is configured to apply an electrical signal Applied to the actuator electrode associated with the particular partition. The system of claim 3, wherein the frequency spectrum of at least one electrical signal includes more than one frequency. The system of claim 3, wherein the actuator comprises a single piece of material mounted to an exterior of the catheter; the actuator electrodes are located on an exterior of the actuator, and the actuator electrodes are spaced separated from each other. The system of claim 5, wherein the actuator comprises a sleeve comprising: a first end; a second end; an inner wall extending from the first end to the second end and mechanically coupled to the exterior of the conduit; the second end is closer to the orifice than the first end; the first section of the actuator is a first portion of the bushing, and the second section of the actuator is a second portion of the bushing; and At least one surface feature is formed on the exterior of the actuator between the first subregion and the second subregion, wherein each surface feature is configured to provide a portion between the first subregion and the second subregion Mechanical isolation. The system of claim 6, wherein the at least one surface feature comprises at least one groove recessed into the exterior surface. The system of claim 7, wherein the at least one surface feature comprises a plurality of grooves; each groove surrounds the sleeve; and each groove has a groove shape. The system of claim 8, further comprising a ground electrode located on the first end and the inner wall of the casing; and wherein One of the plurality of grooves is located between the ground electrode and the first partition. The system of claim 9, wherein at least one of the plurality of grooves has a different shape than at least one other groove. The system of claim 10, wherein the outer wall of the sleeve has a smaller diameter at the second end than at the first end. The system of claim 3, wherein each actuator electrode surrounds an associated partition. The system of claim 3, wherein a minimum frequency in the spectrum of the second actuation signal is greater than a maximum frequency in the spectrum of the first actuation signal. The system of claim 1, wherein the controller is configured to apply the first actuation signal and the second actuation signal comprises the controller being configured to control an electrical signal generator so that the first actuation signal is generated The actuation signal and the second actuation signal are applied to the respective first and second partitions. The system according to claim 14, further comprising the electrical signal generator. The system of claim 14, wherein each of the first actuation signal and the second actuation signal comprises at least one sine wave. The system of claim 1, wherein the molten target material emits EUV light when in a plasma state. The system of claim 1, wherein the first section of the actuators includes a first actuator and the second actuator includes a second actuator different from the first actuator. The system of claim 18, wherein the system further comprises a septum in mechanical communication with an interior of the catheter; and The second actuator is mechanically coupled to the diaphragm. The system of claim 19, further comprising a motion transmission block between the first actuator and the second actuator. The system of claim 20, wherein the first actuator comprises a stack of actuating elements. The system of claim 3, wherein a maximum frequency in the second frequency spectrum is greater than a maximum frequency in the first frequency spectrum. A method comprising: fluidly coupling an orifice of a conduit to a reservoir holding molten target material; applying pressure to the reservoir causing the molten target material to flow in the conduit; applying a first actuation signal to a first section of an actuator mechanically coupled to the catheter, the first actuation signal having a first frequency spectrum; and applying a second actuation signal to a second section of the actuator, wherein the second actuation signal has a second frequency spectrum, and The second spectrum contains higher frequencies than the first spectrum. The method of claim 23, further comprising: A third actuation signal is applied to a third subsection of the actuator, wherein the third actuation signal has a third frequency spectrum. A system comprising: a conduit comprising an orifice configured to be fluidly coupled to a reservoir and emit molten target material; a one-piece actuator mechanically coupled to the catheter, the one-piece actuator comprising a plurality of individually controllable sections; and A controller configured to apply a separate actuation signal to each of at least a first partition and a second partition. The system of claim 25, wherein a groove is formed in an outer surface of the one-piece actuator between the first subregion and the second subregion, and the groove is configured to partially mechanically decouple coupling the first partition and the second partition. A system comprising: a conduit comprising an orifice configured to be fluidly coupled to a reservoir and emit molten target material; an actuator mechanically coupled to the catheter, the actuator comprising a plurality of individually controllable segments, wherein The plurality of individually controllable partitions includes at least a first partition and a second partition, the second subregion is located between the first subregion and the orifice; and the second subregion is smaller than the first subregion; and A controller configured to apply a first actuation signal to the first partition and a second actuation signal to the second partition. The system of claim 27, wherein the second actuation signal includes at least one frequency that is greater than all frequencies in the first actuation signal. An actuator comprising: An actuator body comprising: a ground partition configured to be electrically connected to a reference potential; and a plurality of controllable zones, wherein each controllable zone is configured to receive a control signal, and wherein in operative use, the controllable zones are configured to be mechanically coupled to a conduit such that the controllable zones The movement of the pipe generates a pressure wave in an inner region of the catheter. The actuator of claim 29, wherein the actuator body comprises a single piece of material; the ground zone and the plurality of controllable zones are part of the single piece of material; and the single piece of material comprises a plurality of spatial features; and The grounded subregion is separated from the plurality of controllable subregions by one of the plurality of spatial features, and each controllable subregion is separated from a closest controllable subregion by one of the plurality of spatial characteristics. The actuator of claim 29, wherein at least one of the controllable zones is a separate piece of material that does not directly contact any of the other controllable zones or the zone. The actuator of claim 29, wherein the actuator body includes a substantially cylindrical sidewall configured to surround the conduit.

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