SEMICONDUCTOR PROCESSING TOOL AND METHODS OF OPERATION

Some implementations described herein provide a dual-feedback control system for laser beam targeting in a lithography system such as an EUV lithography system. In addition to using feedback from a high-frequency quad-cell sensor to adjust a target position of the pre-pulse laser beam based on a first portion of a phase of a wavefront of the pre-pulse laser beam, the dual-feedback control system uses feedback from a low-frequency camera sensor to adjust the target position of the pre-pulse laser beam based on a second portion of the phase of the wavefront.

BACKGROUND

An extreme ultraviolet (EUV) radiation source includes a collector, which includes a curved mirror that is configured to collect EUV radiation and to focus the EUV radiation toward an intermediate focus near an intermediate focus cap (IF cap) of the EUV radiation source. The EUV radiation is produced from a laser produced plasma (LPP) that is generated by exposing droplets of tin (Sn) to a carbon dioxide (CO2)-based laser. The Sn droplets are generated by a droplet generator (DG) head, which provides the Sn droplets into a scanner chamber to an irradiation site where the Sn droplets are irradiated by a focused laser beam.

DETAILED DESCRIPTION

A laser source for an extreme ultraviolet (EUV) radiation source may generate laser beams using a multi-pulse technique (or a multi-stage pumping technique), in which the laser source generates a pre-pulse laser beam and main-pulse laser beam to achieve greater heating efficiency in tin-based plasma to increase conversion efficiency. A carbon dioxide (CO2)-based laser source is an example laser source that can provide high power and energy. Moreover, due to the wavelength of the laser beams generated by a CO2-based laser source in an infrared (IR) region, the laser beams may have a high absorption rate in tin, which enables the CO2-based laser source to achieve high power and energy for pumping tin-based plasma.

A laser produced plasma (LPP) may be generated from target material (e.g., tin or another type of target material) droplets, which are shot into a vessel of the EUV radiation source from a droplet generator. The laser source generates and provides a pre-pulse laser beam toward a target material droplet, and the pre-pulse laser beam is absorbed by the target material droplet. This transforms the target material droplet into disc shape or a mist. Subsequently, the laser source provides a main-pulse laser beam with large intensity and energy toward the disc-shaped target material or the target material mist. Here, the atoms of the target material are neutralized, and ions are generated through thermal flux and shock wave. The main-pulse laser beam pumps ions to a higher charge state, which causes the ions to radiate EUV radiation (e.g., EUV light). The EUV radiation is collected at the collector surface and is directed into a chamber of an exposure tool to expose a semiconductor substrate.

In some cases, a target position (e.g., an aim point or a pointing location, among other examples) of a pre-pulse laser beam may be configured to deform a droplet of a target material at a particular location in a path of travel of the droplet in a vessel of an EUV radiation source. The pre-pulse laser beam may transfer a first amount of energy to the droplet of the target material to form a disc-shaped droplet of the target material. Subsequently, a main-pulse laser beam may transfer a second amount of energy to the disc-shaped droplet of the target material at another location in the path of travel to generate a plasma (e.g., a plasma emitting EUV light).

One or more attributes of the disc-shaped droplet (e.g., a shape, a size, an angle, a path, and/or an orientation) of the target material may affect plasma generation during exposure of the disc-shaped droplet to the main-pulse laser beam. For example, an angle or size of the disc-shaped droplet of the target material may result in a portion of the disc-shaped droplet of the target material being unexposed to the main-pulse laser beam (e.g., the main-pulse laser beam “misses” an edge portion of the disc-shaped droplet of the target material). This may result in the portion of the disc-shaped droplet remaining unconverted to plasma, which may reduce the amount of EUV radiation emitted from an EUV radiation source, may increase the inconsistency (which reduces the repeatability) of EUV radiation generation, and/or may result in incomplete exposure of a photoresist on a semiconductor substrate.

One or more factors may impact synchronization of the pre-pulse laser beam and the disc-shaped droplet of the target material. For example, an accuracy of the target position (e.g., an angle, an orientation, and/or a timing of a pre-pulse laser source that provides the pre-pulse laser beam) may impact synchronization of the pre-pulse laser beam and the disc-shaped droplet of the target material, resulting in mutual position errors (e.g., errors in co-location of the pre-pulse laser beam and the disc-shaped droplet of the target material). Additional factors such as movement of a target position over a period of time (e.g., “drifting” of the target position due to thermal conditions experienced by a source of the pre-pulse laser beam) may exacerbate the mutual position errors. A reduction and/or inconsistency in the amount of EUV radiation due to the mutual position errors cause complications while manufacturing semiconductor devices using the EUV radiation source. For example, mutual position errors may reduce a likelihood of maintaining a targeted EUV radiation dose, a targeted yield rate or quality of a semiconductor device manufactured using the EUV radiation source, and/or an efficient use of the target material, among other examples.

Some implementations described herein provide a dual-feedback control system for laser beam targeting in a lithography system such as an EUV lithography system. The dual-feedback control system is configured to control and adjust a target position of a pre-pulse laser beam using a plurality of feedback control loops. In particular, the dual-feedback control system is configured to use feedback from a high-frequency quad-cell sensor to adjust a target position of the pre-pulse laser beam based on a first portion of a phase of the pre-pulse laser beam, and to use feedback from a low-frequency camera sensor to adjust the target position of the pre-pulse laser beam based on a second portion of the phase of the pre-pulse laser beam.

The dual-feedback control system is configured to detect and determine, based on sensor data provided by the camera sensor, a movement of the target position over a period of time that may otherwise be undetected through the use of the quad-cell sensor alone. In this way, the EUV radiation source maintains an accurate target position of the pre-pulse laser beam to maintain a designated EUV radiation dose, a targeted yield rate or quality of semiconductor devices manufactured using the EUV radiation source, and/or an efficient use of the target material, among other examples.

FIGS.1A and1Bare diagrams of an example lithography system100described herein. The lithography system100includes an EUV lithography system or another type of lithography system that is configured to transfer a pattern to a semiconductor substrate using mirror-based optics. The lithography system100may be configured for use in a semiconductor processing environment such as a semiconductor foundry or a semiconductor fabrication facility.

As shown inFIG.1A, the lithography system100includes a radiation source102and an exposure tool104. The radiation source102(e.g., an EUV radiation source or another type of radiation source) is configured to generate radiation106such as EUV radiation and/or another type of electromagnetic radiation (e.g., light). The exposure tool104(e.g., an EUV scanner tool, and EUV exposure tool, or another type of exposure tool) is configured to focus the radiation106onto a reflective reticle108(or a photomask) such that a pattern is transferred from the reticle108onto a semiconductor substrate110using the radiation106.

The radiation source102includes a vessel112and a collector114in the vessel112. The collector114, includes a curved mirror that is configured to collect the radiation106generated by the radiation source102and to focus the radiation106toward an intermediate focus116. The radiation106is produced from a plasma that is generated from droplets118of a target material (e.g., droplets of a target material including Sn droplets or another type of droplets) of a target material being exposed to a laser beam120. The droplets118are provided across the front of the collector114by a droplet generator (DG)122. The droplet generator122is pressurized to provide a fine and controlled output of the droplets118. The laser beam120is provided such that the laser beam120is focused through a window124of the collector114. The laser beam120is focused onto the droplets118which generates the plasma. The plasma produces a plasma emission, some of which is the radiation106.

The exposure tool104includes an illuminator126and a projection optics box (POB)128. The illuminator126includes a plurality of reflective mirrors that are configured to focus and/or direct the radiation106onto the reticle108so as to illuminate the pattern on the reticle108. The plurality of mirrors include, for example, a mirror130aand a mirror130b. The mirror130aincludes a field facet mirror (FFM) or another type of mirror that includes a plurality of field facets. The mirror130bincludes a pupil facet mirror (PFM) or another type of mirror that also includes a plurality of pupil facets. The facets of the mirrors130aand130bare arranged to focus, polarize, and/or otherwise tune the radiation106from the radiation source102to increase the uniformity of the radiation106and/or to increase particular types of radiation components (e.g., transverse electric (TE) polarized radiation, transverse magnetic (TM) polarized radiation). Another mirror132(e.g., a relay mirror) is included to direct radiation106from the illuminator126onto the reticle108.

The projection optics box128includes a plurality of mirrors that are configured to project the radiation106onto the semiconductor substrate110after the radiation106is modified based on the pattern of the reticle108. The plurality of reflective mirrors include, for example, mirrors134a-134f. In some implementations, the mirrors134a-134fare configured to focus or reduce the radiation106into an exposure field, which may include one or more die areas on the semiconductor substrate110.

The exposure tool104includes a wafer stage136(or a substrate stage) configured to support the semiconductor substrate110. Moreover, the wafer stage136is configured to move (or step) the semiconductor substrate110through a plurality of exposure fields as the radiation106transfers the pattern from the reticle108onto the semiconductor substrate110. The wafer stage136is included in a bottom module138of the exposure tool104. The bottom module138includes a removable subsystem of the exposure tool104. The bottom module138may slide out of the exposure tool104and/or otherwise may be removed from the exposure tool104to enable cleaning and inspection of the wafer stage136and/or the components of the wafer stage136. The bottom module138isolates the wafer stage136from other areas in the exposure tool104to reduce and/or minimize contamination of the semiconductor substrate110. Moreover, the bottom module138may provide physical isolation for the wafer stage136by reducing the transfer of vibrations (e.g., vibrations in the semiconductor processing environment in which the lithography system100is located, vibrations in the lithography system100during operation of the lithography system100) to the wafer stage136and, therefore, the semiconductor substrate110. This reduces movement and/or disturbance of the semiconductor substrate110, which reduces the likelihood that the vibrations may cause a pattern misalignment.

The exposure tool104also includes a reticle stage140that is configured to support and/or secure the reticle108. Moreover, the reticle stage140is configured to move or slide the reticle108through the radiation106such that the reticle108is scanned by the radiation106. In this way, a pattern that is larger than the field or beam of the radiation106may be transferred to the semiconductor substrate110.

The lithography system100includes a laser source142. The laser source142is configured to generate one or more laser beams120. The laser source142may include a CO2-based laser source or another type of laser source. Due to the wavelength of the laser beams generated by a CO2-based laser source in an IR region, the laser beams may be highly absorbed by tin, which enables the CO2-based laser source to achieve high power and energy for pumping tin-based plasma. In some implementations, the one or more laser beams120include a pre-pulse laser beam that includes a plurality of types of laser beams that the laser source142generates using a multi-pulse technique (or a multi-stage pumping technique), in which the laser source142generates a pre-pulse laser beam and a main-pulse laser beam to achieve greater heating efficiency of tin (Sn)-based plasma to increase conversion efficiency.

As described in greater detail herein, the laser source142may perform a combination of operations to deform the droplet118(e.g., deform the droplet118into a disc shape or a mist using the pre-pulse laser beam) and pump ions of the droplet118to a higher charge state (e.g., pump ions of the droplet118, after deformation, using the main-pulse laser beam), which causes the ions to radiate the radiation106(e.g., EUV light).

The radiation106is collected by the collector114and directed out of the vessel112and into the exposure tool104toward the mirror130aof the illuminator126. The mirror130areflects the radiation106onto the mirror130b, which reflects the radiation106onto the mirror132toward the reticle108. The radiation106is modified by the pattern in the reticle108. In other words, the radiation106reflects off of the reticle108based on the pattern of the reticle108. The reflective reticle108directs the radiation106toward the mirror134ain the projection optics box128, which reflects the radiation106onto the mirror134b. The radiation106continues to be reflected and reduced in the projection optics box128by the mirrors134c-134f. The mirror134freflects the radiation106onto the semiconductor substrate110such that the pattern of the reticle108is transferred to the semiconductor substrate110. The above-described exposure operation is an example, and the lithography system100may operate according to other EUV techniques and radiation paths that include a greater quantity of mirrors, a lesser quantity of mirrors, and/or a different configuration of mirrors.

FIG.1Bis a diagram of an example laser source142described herein for use in the lithography system100ofFIG.1A. The laser source142is configured to generate and provide a pre-pulse laser beam120ato a radiation source (e.g., the radiation source102) through the window124of the collector114for EUV radiation generation. The pre-pulse laser beam120amay generate a disc-shaped droplet of the target material118b(e.g., apply energy to a droplet of the target material118ato deform the droplet of the target material118a) within a vessel of the radiation source (e.g., the vessel112).

As shown inFIG.1B, the laser source142includes a pre-pulse seed laser144(e.g., a drive laser). The pre-pulse seed laser144includes a semiconductor laser driver (e.g., a quantum dot laser driver, a diode laser driver), a resonator (or resonation chamber), an oscillator, a laser mode actuator or controller, and/or another component that is configured to generate a seed pre-pulse laser beam146. The seed pre-pulse laser beam146is provided to a pre-pulse amplifier chain148, which may include one or more laser amplifiers. The one or more laser amplifiers may include a preamplifier, a main amplifier, and/or another type of amplifier that is configured to amplify the seed pre-pulse laser beam146to form the pre-pulse laser beam120a.

In some implementations, the laser source142includes one or more other components, such as an optical component (e.g., a filter) configured to select a particular wavelength for the seed pre-pulse laser beam146and/or adjust or modify other parameters of the seed pre-pulse laser beam146. The pre-pulse laser beam120amay be provided to the radiation source102by mirrors150, including mirror150aand mirror150b, among other examples. The mirrors150may include a concave or a convex shape, may include a multi-layer mirror, or may include one or more facets, among other examples. In some implementations, the laser source142includes a greater or a lesser quantity of the mirrors150.

The laser source142may include motors152(e.g., motor152aand motor152b, among other examples) to adjust respective orientations (e.g., respective angular positions, respective linear positions, among other examples) of the mirrors150. Examples of the motors152include a stepper motor, a servo motor, or a linear induction motor, among other examples. Furthermore, the motors152may be mechanically coupled to the mirrors150using one or more of a gimble component, a linear bearing component, a rotational bearing component, or a ball-screw component, among other examples. In some implementations, the laser source142includes a greater or a lesser quantity of the motors152.

In combination, the mirrors150and the motors152are arranged to focus and/or otherwise direct the pre-pulse laser beam120ato a target position154. The location of the target position154in the vessel112may be included in a path156along which the droplet of the target material118atravels in the vessel112. The location of the target position154of the pre-pulse laser beam120amay be different from a location of a target position of a main-pulse laser beam provided by the laser source142.

In some implementations, the target position154corresponds to a pre-pulse laser focus region at which the pre-pulse laser beam120airradiates the droplet of the target material118aalong the path156to deform the droplet of the target material118a. The laser source142may be configured such that, at the target position154, the pre-pulse laser beam120airradiates the droplet of the target material118awith a beam diameter of approximately 80 micrometers (μm) to approximately 120 μm. However, other values for the beam diameter are within the scope of the present disclosure. A designated accuracy of the target position154may be in a range from approximately −10 μm to approximately +10 μm so that a partial deformation of the droplet of the target material118adoes not reduce an amount of EUV energy during a subsequent pulsing of the disc-shaped droplet of the target material118bby a main-pulse laser beam. However, other values for the designated accuracy are within the scope of the present disclosure.

As an example, and if the accuracy of the target position154ranges from approximately −20 μm to approximately +20 μm, the EUV energy during the subsequent pulsing of the disc-shaped droplet of the target material118bby the main-pulse laser beam may drop by a range from approximately 3 millijoules (mJ) to approximately 5 mJ. However, other values for the drop in EUV energy are within the scope of the present disclosure.

The laser source142may include a quad-cell sensor optical component158a. The quad-cell sensor optical component158aincludes a beam splitter, a multiple-layer mirror, a multiple-layer reflector, and/or another type of optical component. The quad-cell sensor optical component158aredirects a portion120a1of the pre-pulse laser beam120aand provides the portion120a1to a quad-cell sensor160. The quad-cell sensor160may include, for example, arrays of photodiodes that convert light into an electrical current. The quad-cell sensor160is configured to generate sensor data based on one or more properties of a wavefront (e.g., an intensity, a frequency, a phase angle, among other examples) associated with portion120a1across each cell of the quad-cell sensor160(e.g., four cells). The quad-cell sensor160may provide, to a controller of the laser source142, the sensor data corresponding to the one or more properties. The controller may determine, based on the sensor data, a structure of the wavefront, a phase of the wavefront, an angle of incidence164a(e.g., a three-dimensional angle of incidence), and/or another attribute of the wavefront. In some implementations, the controller uses Zernike polynomial techniques to determine one or more attributes of the wavefront based on the sensor data.

The laser source142may include a camera sensor optical component158b. The camera sensor optical component158bincludes a beam splitter, a multiple-layer mirror, a multiple-layer reflector, and/or another type of optical component. The camera sensor optical component158bredirects a portion120a2of the pre-pulse laser beam120aand provides the portion120a2to a camera sensor162. The camera sensor162may include a complimentary metal-oxide semiconductor sensor or a charge-coupled device sensor, among other examples. The camera sensor162is configured to generate sensor data based on one or more properties of a wavefront (e.g., an intensity, a frequency, a phase, among other examples) associated with the portion120a2across a field of view of the camera sensor162and provide, to the controller, data corresponding to the one or more properties. The controller may determine, based on the sensor data, a structure of the wavefront, a phase of the wavefront, an angle of incidence164b(e.g., a three-dimensional angle of incidence), and/or another attribute of the wavefront. In some implementations, the controller uses Zernike polynomial techniques to determine one or more attributes of the wavefront based on the sensor data.

One or more variations in the angle of incidence164aand/or the angle of incidence164bmay be proportional to a variation in an angle of incidence164c(e.g., a three-dimensional angle of incidence) and/or proportional to a variation in an angle of incidence164d(e.g., a three-dimensional angle of incidence) of the pre-pulse laser beam120a. This may occur because the pre-pulse laser beam120ais redirected by the mirrors150to the target position154. The laser source142(e.g., the controller of the laser source142) may determine, based on a detected variation in the angle of incidence164aand/or a detected variation in the angle of incidence164b, that the target position154has drifted and is not properly aligned to the focus region (e.g., aligned to an intercept point, or mutual location, for intercepting the droplet of the target material118a.) The controller may provide, based on determining that the target position154has drifted, one or more signals to the motors152to adjust an orientation of one or more of the mirrors150to properly align the target position154to the focus region.

In some implementations, adjustments to the target position154(e.g., adjustments to one or more orientations of the mirrors150by the motors152) are made to synchronize a location of the pre-pulse laser beam120aand a location of the droplet of the target material118atraversing the path156within the vessel of the EUV radiation source.

In some implementations, the quad-cell sensor optical component158aand the camera sensor optical component158bare co-located. In some implementations, the quad-cell sensor160and the camera sensor162are co-located. In some implementations, the quad-cell sensor160and the camera sensor162are included in the same device. In some implementations, the quad-cell sensor160and the camera sensor162are included in the same system on chip (SoC) and/or on the same semiconductor die. In some implementations, the quad-cell sensor160and the camera sensor162are included in the same integrated circuit.

AlthoughFIG.1Bdescribes aspects of the laser source142generating the pre-pulse laser beam120aand adjusting the target position154to align with the pre-pulse focus region, aspects ofFIG.1Bare also applicable to generating a main-pulse laser beam and adjusting a targeting position of the main-pulse laser beam to align to a main-pulse laser focus region (e.g., a region at which the main-pulse laser beam generates a plasma from the disc-shaped droplet of the target material118b).

As indicated above,FIGS.1A and1Bare provided as examples. Other examples may differ from what is described with regard toFIGS.1A and1B. For example, another example may include additional components, fewer components, different components, or differently arranged components than those shown inFIGS.1A and1B. Additionally, or alternatively, a set of components (e.g., one or more components) ofFIGS.1A and1Bmay perform one or more functions described herein as being performed by another set of components.

FIG.2is a diagram of an example implementation200of the pre-pulse laser beam120aand a main-pulse laser beam120bdescribed herein. In the example implementation200, the laser source142uses a multi-pulse technique (or a multi-stage pumping technique) to generate the pre-pulse laser beam120aand the main-pulse laser beam120bto achieve greater heating efficiency of droplets of a target material to increase conversion efficiency.

In some implementations, a droplet generator (e.g., the droplet generator122ofFIG.1A) provides the droplet of the target material118a(e.g., multiples of the droplet of the target material118a) along the path156at a frequency of approximately 50 kilohertz (kHz) and at a velocity of approximately 80 meters per second (m/s). Furthermore, the droplet of the target material118amay have a diameter in a range from approximately 20 μm to approximately 30 μm. However, other values for the frequency, velocity, and diameter of the droplet of the target material118aare within the scope of the present disclosure.

In some implementations, and as shown inFIG.2, at a first location within the vessel112, the pre-pulse laser beam120aprovides a first amount of energy to a droplet of the target material118a. The energy transforms the droplet of the target material118ainto the disc-shaped droplet of the target material118b. The disc-shaped droplet of the target material118bmay include a disc shape, a “pancake” shape, a mist, or another shape. The disc-shaped droplet of the target material118bincludes a greater surface area for excitation by the main-pulse laser beam120brelative to the droplet of the target material118a, which increases the conversion rate of the target material to a plasma. Within the vessel112, the disc-shaped droplet of the target material118btraverses the path156that brings the disc-shaped droplet of the target material118bto a second location within the vessel112. At the second location, the main-pulse laser beam120bprovides a second amount of energy to the disc-shaped droplet of the target material118bto create a plasma202that generates EUV radiation as the plasma202dissipates.

In some implementations, timing of pulsing of laser beams from the pre-pulse laser beam120aand the main-pulse laser beam120bis dependent on a velocity of the disc-shaped droplet of the target material118b, the size of the disc-shaped droplet of the target material118b, the shape of the disc-shaped droplet of the target material118b, the path of travel of the disc-shaped droplet of the target material118b, and/or another parameter. As an example, the disc-shaped droplet of the target material118bmay continue traversing the path156at a rate of approximately 60 m/s to approximately 75 m/s, in which case timing of the pulsing of the main-pulse laser beam120bmay be offset from (e.g., lag behind) the pulse of the pre-pulse laser beam120aby approximately 3000 microseconds. However, other values for the rate of travel of the disc-shaped droplet of the target material118band other values for the timing or offset between the pre-pulse laser beam120aand the main-pulse laser beam120bare within the scope of the present disclosure.

FIG.3is a diagram of an example implementation300of the quad-cell sensor160described herein.FIG.3shows the portion120a1(e.g., the portion120a1of the pre-pulse laser beam120a) approaching the quad-cell sensor160at the angle of incidence164a. The portion120a1includes multiples of the wavefront302.

In some implementations, the quad-cell sensor160includes an aperture304, through which only a portion306of a phase of the wavefront302(e.g., multiples of the portion306of the phase of the wavefront302) pass. The quad-cell sensor160may detect one or more properties of the portion306of the phase (e.g., an intensity, a frequency, and/or a phase angle, among other examples) and provide, to a controller, sensor data corresponding to the one or more properties. The controller may perform, based on the sensor data, Zernike computations (e.g., compute Zernike coefficients, compute Zernike modes, or compute Zernike moments, among other examples) to determine a variation in a location308of the portion120a1(e.g., corresponding to a change in the angle of incidence164a). The variation in the location308may be proportional to a change in a target position of a pre-pulse laser beam (e.g., proportional to a change in the target position154, or the angle of incidence164d, of the pre-pulse laser beam120a).

FIGS.4A and4Bare diagrams of example implementations400of phase images described herein. The implementations400include example phase images of a wavefront (e.g., the wavefront302) that may be computed by a controller using sensor data received from a quad-cell sensor (e.g., the quad-cell sensor160) and a camera sensor (e.g., the camera sensor162).

FIG.4Ashows an example phase image402that includes a first portion306aof a phase of the wavefront302and a second portion404aof the phase. A size of the first portion306aof the phase, corresponding to a portion of the phase of the wavefront302passing through an aperture of the quad-cell sensor160(e.g., the aperture304) and that is detected by the quad-cell sensor160, is less relative to a size of the second portion404aof the phase that is detected by the camera sensor162. Furthermore, the first portion306aof the phase is encompassed by the second portion404a(e.g., the second portion404aencompasses the first portion306a). In other words, the first portion306aof the phase is fully included in the second portion404aof the phase. In other implementations, the first portion306aand the second portion404aare partially overlapping portions.

In some implementations, and due to the size of the first portion306anot capturing outer regions of the phase, accuracy of the controller computing variations in a location of a portion of a pre-pulse laser beam (e.g., the variation in the location308of the portion120a1of the pre-pulse laser beam120a) may be reduced. In such implementations, and due to the larger size of the second portion404arelative to the size of the first portion306a, the controller is able to compensate by computing variations in a location of another portion of the pre-pulse laser beam (e.g., the portion120a2of the pre-pulse laser beam120a) using the data received from the camera sensor162.

FIG.4Bshows an example phase image406that includes a first portion306bof a phase of the wavefront302and a second portion404bof the phase. A size of the first portion306bof the phase, corresponding to a portion of the phase of the wavefront302passing through the aperture304and that is detected by the quad-cell sensor160, is less relative to a size of the second portion404bof the phase that is detected by the camera sensor162. Furthermore, the first portion306bof the phase is encompassed by the second portion404b(e.g., the second portion404bencompasses the first portion306b).

In some implementations, and due to the size of the first portion306bnot capturing outer regions of the phase, accuracy of the controller computing variations in a location of a portion of a pre-pulse laser beam (e.g., the variation in the location308of the portion120a1of the pre-pulse laser beam120a) may be reduced. In such implementations, and due to the larger size of the second portion404brelative to the size of the first portion306b, the controller is able to compensate by computing variations in a location of another portion of the pre-pulse laser beam (e.g., the portion120a2of the pre-pulse laser beam120a) using the data received from the camera sensor162.

As indicated above,FIGS.4A and4Bare provided as examples. Other examples may differ from what is described with regard toFIGS.4A and4B.

FIGS.5A and5Bare diagrams of an example implementation500of a controller502that is configured to use dual-feedback from a quad-cell sensor and a camera sensor described herein. The controller502may include a processor or a combination of a processor and memory, among other examples.

FIG.5Ashows the controller502is communicatively connected to components of a mirror system506(e.g., the mirror150a, the mirror150b, the motor152a, the motor152b, the quad-cell sensor160, or the camera sensor162, among other examples) using one or more communication links504(e.g., one or more wireless-communication links, one or more wired-communication links, or a combination of one or more wireless-communication links and one or more wired-communication links, among other examples).

In some implementations, the controller502transmits a signal508to a component of the mirror system506. For example, the controller502may transmit, to the motor152a, the signal508to change an orientation of the mirror150a, the signal508to the motor152bto change an orientation of the mirror150b, or the signal508to another component (e.g., the quad-cell sensor160or the camera sensor162, among other examples) of the mirror system506to change a calibration setting of the component.

In some implementations, the controller502receives a signal510from a component of mirror system506. For example, the controller502may receive the signal510from the quad-cell sensor160, where the signal510includes data associated with a portion of a wavefront (e.g., the first portion306a, among other examples). As another example, the controller502may receive the signal510from the camera sensor, where the signal510includes data associated with a portion of a wavefront (e.g., the second portion404a, among other examples).

In some implementations, the controller502may perform processes that include receiving, from the quad-cell sensor160, first data associated with a pre-pulse laser beam (e.g., receive, via the signal510, data associated with the portion120a1of the pre-pulse laser beam120a) provided to an EUV radiation source (e.g., the radiation source102). Additionally, or alternatively, the controller502may perform processes that include receiving, from the camera sensor162, second data associated with the pre-pulse laser beam120a(e.g., data associated with the portion120a2of the pre-pulse laser beam120a). Additionally, or alternatively, the controller502may perform processes that include providing, based on the first data and the second data, the signal508to cause an adjustment to a target position (e.g., the target position154) of the pre-pulse laser beam120a.

In some implementations, the controller502may perform processes that include receiving, from the camera sensor162, first data associated with a pre-pulse laser beam120aprovided by a laser source (e.g., data associated with the portion120a2of the pre-pulse laser beam120a) and determining, based on a comparison of the first data and second data, that a target position (e.g., the target position154) of the pre-pulse laser beam120ahas moved over a time duration. Additionally, or alternatively, the controller502may perform processes that include determining, based on determining that the target position154of the pre-pulse laser beam120ahas moved over the time duration, to adjust a calibration setting of the mirror system506(e.g., a calibration setting of the motors152, the quad-cell sensor160, or the camera sensor162, among other examples) controlling the target position154of the pre-pulse laser beam120a. Additionally, or alternatively, the controller502may perform processes that include providing, based on determining to adjust the calibration setting of the mirror system506, the signal508to the mirror system506to cause an adjustment to the calibration setting. In some implementations, the adjustment to the calibration setting is to cause the target position154to align to a focus region in which a droplet of a target material (e.g., the droplet of the target material118a) is to be deformed by the pre-pulse laser beam120a.

FIG.5Bshows additional aspects of the controller502in communication with the motors152(e.g., the motor152acontrolling an orientation of the mirror150aand/or the motor152bcontrolling an orientation of the mirror150b). As shown inFIG.5B, the controller502is configured as part of a dual-feedback system. As part of the dual-feedback system, the controller502may receive first data from the quad-cell sensor160at a first frequency using the feedback loop512and may receive second data from the camera sensor162at a second frequency using the feedback loop514.

In some implementations, the first frequency (e.g., an operating frequency of the quad-cell sensor160) is in a range from approximately 3 kHz to approximately 5 kHz. In some implementations, the second frequency (e.g., an operating frequency of the camera sensor162) is in a range from approximately 22 Hz to approximately 24 Hz. Such a combination of frequencies may increase consistency and accuracy of the target position, while preserving or reducing computing resources needed by the controller502. For example, the range of the first frequency may increase a target position adjustment rate to fine-tune target position adjustments made to intercept a stream of droplets of a target material (e.g., a stream of multiples of the droplet of the target material118a) being provided by a droplet generator (e.g., the droplet generator122) at a rate of 50 kilohertz. Such tuning, based on the first data that includes a reduced amount of data relative to the second data, may correspond to a rate of approximately once every ten to fifteen droplets of the target material. Additionally, and while the second data from the camera sensor162(e.g., an increased amount of data relative to the first data) may increase an accuracy of the target position154by compensating for portions of a wavefront (e.g., the wavefront302) that the quad-cell sensor160may not detect, the range of the second frequency may preserve or reduce resources (e.g., computing resources) needed by the controller502to process the second data. However, other values and ranges for the first frequency and the second frequency are within the scope of the present disclosure.

In some implementations, the controller502may receive an input from another component516(e.g., a memory device, a processor, or a radiation sensor, among other examples). The input may include reference data (e.g., data corresponding to a reference wavefront of a reference pre-pulse laser beam determined to have been aligned to the focus region), data of a reference Zernike computation, or an amount of EUV radiation being generated by a radiation source (e.g., the radiation source102) using the pre-pulse laser beam120a, among other examples.

In some implementations, a system (e.g., the lithography system100) includes the controller502. Such a system may include a radiation source (e.g., the radiation source102) that is configured to generate EUV light from a droplet of a target material (e.g., generate EUV light from the droplet118of the target material). The system may include a mirror (e.g., the mirror150b) configured to redirect a laser beam (e.g., the pre-pulse laser beam120a) from a laser source (e.g., the pre-pulse seed laser144and the pre-pulse amplifier chain148) of the radiation source to the target position154corresponding to a focus region. The system may further include the quad-cell sensor160configured to operate at the first frequency and the camera sensor162configured to operate at the second frequency that is less than the first frequency. The controller502may be configured to receive, from the quad-cell sensor160at the first frequency, first data associated with the laser beam, and receive, from the camera sensor162at the second frequency, second data associated with the laser beam. The controller502may further be configured to determine, based on one or more of the first data or the second data, to adjust an orientation of the mirror150bto adjust the target position154and provide, based on determining to adjust the orientation of the mirror150bto adjust the target position154, a signal (e.g., the signal508) to cause an adjustment to the orientation of the mirror to adjust the target position to align to the focus region.

In connection withFIGS.5A and5B, and elsewhere herein, the controller502may adjust the target position using a machine learning model. The machine learning model may include and/or may be associated with one or more of a neural network model, a random forest model, a clustering model, or a regression model, among other examples. In some implementations, the controller502uses the machine learning model to adjust the target position by providing candidate calibration setting and/or motor adjustments as input to the machine learning model, and using the machine learning model to determine a likelihood, probability, or confidence that a particular outcome (e.g., an amount of an increase in EUV radiation or an increase target position accuracy, among other examples) for a subsequent exposure operation will be achieved using the candidate parameters. In some implementations, the controller502provides a designated amount of EUV radiation and/or a designated target position accuracy as input to the machine learning model, and the controller502uses the machine learning model to determine or identify a particular combination of calibration settings and/or motor adjustments that are likely to achieve the designated amount(s).

The controller502(or another system) may train, update, and/or refine the machine learning model to increase the accuracy of the outcomes and/or parameters determined using the machine learning model. The controller502may train, update, and/or refine the machine learning model based on feedback and/or results from the subsequent exposure operation, as well as from historical or related exposure operations (e.g., from hundreds, thousands, or more historical or related exposure operations) performed by an exposure tool (e.g., the exposure tool104of the lithography system100, among other examples).

As an example, in some implementations the controller502determines a correlation relating to an increase in an amount radiation provided by a radiation source (e.g., the radiation source102) based on a signal (e.g., the signal508) that causes the adjustment to the target position. The controller502then provides information relating to the correlation to update the machine learning model to estimate the increase in the amount of radiation based on the signal508to cause the adjustment.

As another example, in some implementations the controller502determines a correlation relating to the amount of radiation provided by the radiation source including a laser source (e.g., the laser source142including the pre-pulse seed laser144and the pre-pulse amplifier chain148) and a calibration setting of a mirror system (e.g., the mirror system506). The controller502then provides information relating to the correlation to update the machine learning model to estimate the amount of EUV radiation based on the calibration setting.

As indicated above,FIGS.5A and5Bare provided as examples. Other examples may differ from what is described with regard toFIGS.5A and5B. For example, another example may include additional components, fewer components, different components, or differently arranged components than those shown inFIGS.5A and5B. Additionally, or alternatively, a set of components (e.g., one or more components) ofFIGS.5A and5Bmay perform one or more functions described herein as being performed by another set of components.

FIG.6is a diagram of example responses600of a radiation source (e.g., the radiation source102) using the dual-feedback control system described herein (e.g., the controller502receiving feedback from the quad-cell sensor160and the camera sensor162).

Example response602shows a potential change in a target position (e.g., a “drifting” of the target position154) of a pre-pulse laser beam (e.g., the pre-pulse laser beam120a) across a period of time. Example response602includes a time domain604and position domain606. As shown, a potential change in a target position608across the time domain604may result from thermal effects (e.g., “cold-to-hot” effects) upon a source of the pre-pulse laser beam120a(e.g., thermal effects upon the pre-pulse seed laser144and the pre-pulse amplifier chain148).

Example response610shows adjustment responses to the target position154made by a controller (e.g., the controller502) based on feedback from the quad-cell sensor160and/or the camera sensor162. As shown, a camera sensor adjustment response612and a quad-cell sensor adjustment response614combine to mitigate, across the time domain604, a cumulative position error response616in the position domain606.

Example response618shows the net effect to an amount of radiation (e.g., EUV energy) provided by the radiation source102based on the adjustments of the target position154shown by example response610. Example response618includes the time domain604and the radiation energy domain620. As shown in example response618, and as a result of the adjustments in the target position154, a maintained radiation energy response622is realized across the time domain604. A degraded radiation energy response624is avoided across the time domain604.

FIG.7is a diagram of example components of a device700, which may correspond to the lithography system100, the radiation source102, the motors152, the quad-cell sensor160, the camera sensor162, and/or the controller502. In some implementations, the lithography system100, the radiation source102, the motors152, the quad-cell sensor160, the camera sensor162, and/or the controller502include one or more devices700and/or one or more components of device700. As shown inFIG.7, device700may include a bus710, a processor720, a memory730, an input component740, an output component750, and a communication component760.

Bus710includes one or more components that enable wired and/or wireless communication among the components of device700. Bus710may couple together two or more components ofFIG.7, such as via operative coupling, communicative coupling, electronic coupling, and/or electric coupling. Processor720includes a central processing unit, a graphics processing unit, a microprocessor, a controller, a microcontroller, a digital signal processor, a field-programmable gate array, an application-specific integrated circuit, and/or another type of processing component. Processor720is implemented in hardware, firmware, or a combination of hardware and software. In some implementations, processor720includes one or more processors capable of being programmed to perform one or more operations or processes described elsewhere herein.

Memory730includes volatile and/or nonvolatile memory. For example, memory730may include random access memory (RAM), read only memory (ROM), a hard disk drive, and/or another type of memory (e.g., a flash memory, a magnetic memory, and/or an optical memory). Memory730may include internal memory (e.g., RAM, ROM, or a hard disk drive) and/or removable memory (e.g., removable via a universal serial bus connection). Memory730may be a non-transitory computer-readable medium. Memory730stores information, instructions, and/or software (e.g., one or more software applications) related to the operation of device700. In some implementations, memory730includes one or more memories that are coupled to one or more processors (e.g., processor720), such as via bus710.

Input component740enables device700to receive input, such as user input and/or sensed input. For example, input component740may include a touch screen, a keyboard, a keypad, a mouse, a button, a microphone, a switch, a sensor, a global positioning system sensor, an accelerometer, a gyroscope, and/or an actuator. Output component750enables device700to provide output, such as via a display, a speaker, and/or a light-emitting diode. Communication component760enables device700to communicate with other devices via a wired connection and/or a wireless connection. For example, communication component760may include a receiver, a transmitter, a transceiver, a modem, a network interface card, and/or an antenna.

Device700may perform one or more operations or processes described herein. For example, a non-transitory computer-readable medium (e.g., memory730) may store a set of instructions (e.g., one or more instructions or code) for execution by processor720. Processor720may execute the set of instructions to perform one or more operations or processes described herein. In some implementations, execution of the set of instructions, by one or more processors720, causes the one or more processors720and/or the device700to perform one or more operations or processes described herein. In some implementations, hardwired circuitry is used instead of or in combination with the instructions to perform one or more operations or processes described herein. Additionally, or alternatively, processor720may be configured to perform one or more operations or processes described herein. Thus, implementations described herein are not limited to any specific combination of hardware circuitry and software.

The number and arrangement of components shown inFIG.7are provided as an example. Device700may include additional components, fewer components, different components, or differently arranged components than those shown inFIG.7. Additionally, or alternatively, a set of components (e.g., one or more components) of device700may perform one or more functions described as being performed by another set of components of device700.

FIG.8is a flowchart of an example process800relating to adjusting a target position of a pre-pulse laser beam described herein. In some implementations, one or more process blocks ofFIG.8are performed by a lithography system including a radiation source (e.g., the lithography system100including the radiation source102). In some implementations, one or more process blocks ofFIG.8are performed by another device or a group of devices separate from or including the lithography system or the radiation source, such as one or more motors (e.g., the motors152), a quad-cell sensor (e.g., the quad-cell sensor160), a camera sensor (e.g., the camera sensor162), and/or a controller (e.g., the controller502). Additionally, or alternatively, one or more process blocks ofFIG.8may be performed by one or more components of device700, such as processor720, memory730, input component740, output component750, and/or communication component760.

As shown inFIG.8, process800may include receiving, from a quad-cell sensor, first data associated with a pre-pulse laser beam provided to an EUV radiation source (block810). For example, the controller502may receive, from a quad-cell sensor160, first data associated with a pre-pulse laser beam120aprovided to an EUV radiation source102, as described above.

As further shown inFIG.8, process800may include receiving, from a camera sensor, second data associated with the pre-pulse laser beam (block820). For example, the controller502may receive, from the camera sensor162, second data associated with the pre-pulse laser beam120a, as described above.

As further shown inFIG.8, process800may include providing, based on the first data and the second data, a signal to cause an adjustment to a target position of the pre-pulse laser beam (block830). For example, the controller502may provide, based on the first data and the second data, a signal708to cause an adjustment to a target position154of the pre-pulse laser beam120a, as described above.

In a first implementation, the first data corresponds to a first portion306aof a phase of a wavefront302of the pre-pulse laser beam120aand the second data corresponds to a second portion404aof the phase of the wavefront302the pre-pulse laser beam120a.

In a second implementation, alone or in combination with the first implementation, a first size of the first portion306aof the phase is less relative to a second size of the second portion404aof the phase.

In a third implementation, alone or in combination with one or more of the first and second implementations, the first portion306aof the phase is encompassed by the second portion404aof the phase.

In a fourth implementation, alone or in combination with one or more of the first through third implementations, the signal508to cause the adjustment to the target position154of the pre-pulse laser beam120ais to synchronize a first location of the pre-pulse laser beam120aand a second location of a droplet of a target material118atraversing a path156within a vessel112of the EUV radiation source102.

In a fifth implementation, alone or in combination with one or more of the first through fourth implementations, receiving the first data includes receiving the first data at a first frequency, and receiving the second data includes receiving the second data at a second frequency that is less than the first frequency.

In a sixth implementation, alone or in combination with one or more of the first through fifth implementations, the first frequency is in a first range from approximately 3 kilohertz to approximately 5 kilohertz and the second frequency is in a second range from approximately 22 hertz to approximately 26 hertz.

In a seventh implementation, alone or in combination with one or more of the first through sixth implementations, providing the signal508to cause the adjustment to the target position includes providing the signal to cause the adjustment to the target position to compensate for a drift in the target position that results from a thermal effect on a laser source that generates the pre-pulse laser beam.

In an eighth implementation, alone or in combination with one or more of the first through seventh implementations, providing the signal508to cause the adjustment to the target position154includes determining, based on the first data and the second data, to adjust an orientation of at least one mirror150bof a mirror system506controlling the target position154of the pre-pulse laser beam120a.

In a ninth implementation, alone or in combination with one or more of the first through eight implementations, process800includes determining a correlation relating to an increase in an amount of EUV radiation provided by the EUV radiation source102based on the signal508to cause the adjustment, and providing information relating to the correlation to update a machine learning model that estimates the increase in the amount of EUV radiation based on the signal508to cause the adjustment.

AlthoughFIG.8shows example blocks of process800, in some implementations, process800includes additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted inFIG.8. Additionally, or alternatively, two or more of the blocks of process800may be performed in parallel.

FIG.9is a flowchart of an example process900relating to adjusting a target position of a pre-pulse laser beam described herein. In some implementations, one or more process blocks ofFIG.9are performed by a lithography system including a radiation source (e.g., the lithography system100including the radiation source102). In some implementations, one or more process blocks ofFIG.9are performed by another device or a group of devices separate from or including the lithography system or the radiation source, such as one or more motors (e.g., the motors152), a quad-cell sensor (e.g., the quad-cell sensor160), a camera sensor (e.g., the camera sensor162), and/or a controller (e.g., the controller502). Additionally, or alternatively, one or more process blocks ofFIG.9may be performed by one or more components of device700, such as processor720, memory730, input component740, output component750, and/or communication component760.

As shown inFIG.9, process900may include receiving, from a camera sensor, first data associated with a pre-pulse laser beam provided by a laser source (block910). For example, the controller502may receive, from a camera sensor162, may receive first data associated with a pre-pulse laser beam120aprovided by a laser source (e.g., the pre-pulse seed laser144and the pre-pulse amplifier chain148), as described above.

As further shown inFIG.9, process900may include determining, based on a comparison of the first data and second data, that a target position of the pre-pulse laser beam has moved over a time duration (block920). For example, the controller502may determine, based on a comparison of the first data and second data, that a target position154of the pre-pulse laser beam120ahas moved over a time duration, as described above.

As further shown inFIG.9, process900may include determining, based on determining that the target position of the pre-pulse laser beam has moved over the time duration, to adjust a calibration setting of a mirror system controlling the target position of the pre-pulse laser beam (block930). For example, the controller502may determine, based on determining that the target position154of the pre-pulse laser beam120ahas moved over the time duration, to adjust a calibration setting of a mirror system506controlling the target position154of the pre-pulse laser beam120a, as described above.

As further shown inFIG.9, process900may include providing, based on determining to adjust the calibration setting of the mirror system, a signal to the mirror system to cause an adjustment to the calibration setting (block940). For example, the controller502may provide, based on determining to adjust the calibration setting of the mirror system506, a signal508to the mirror system506to cause an adjustment to the calibration setting. In some implementations, the adjustment to the calibration setting is to cause the target position154to align to a focus region in which a droplet of a target material118ais to be deformed by the pre-pulse laser beam120a, as described above.

In a first implementation, the first data includes data corresponding to a wavefront302of the pre-pulse laser beam120a.

In a second implementation, alone or in combination with the first implementation, the second data includes reference data corresponding to a reference wavefront of a reference pre-pulse laser beam determined to have been aligned to the focus region.

In a third implementation, alone or in combination with one or more of the first and second implementations, process900includes determining a correlation relating to an amount of EUV radiation provided by an EUV radiation source102including the laser source (e.g., the pre-pulse seed laser144and the pre-pulse amplifier chain148) and the calibration setting, and providing information relating to the correlation to update a machine learning model that estimates the amount of EUV radiation based on the calibration setting.

AlthoughFIG.9shows example blocks of process900, in some implementations, process900includes additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted inFIG.9. Additionally, or alternatively, two or more of the blocks of process900may be performed in parallel.

FIG.10is a flowchart of an example process1000relating to adjusting a target position of a pre-pulse laser beam described herein. In some implementations, one or more process blocks ofFIG.8are performed by a lithography system including a radiation source (e.g., the lithography system100including the radiation source102). In some implementations, one or more process blocks ofFIG.10are performed by another device or a group of devices separate from or including the lithography system or the radiation source, such as one or more motors (e.g., the motors152), a quad-cell sensor (e.g., the quad-cell sensor160), a camera sensor (e.g., the camera sensor162), and/or a controller (e.g., the controller502). Additionally, or alternatively, one or more process blocks ofFIG.10may be performed by one or more components of device700, such as processor720, memory730, input component740, output component750, and/or communication component760.

As shown inFIG.10, process1000may include receiving a semiconductor substrate coated with a photoresist material (block1010). For example, the lithography system100may receive a semiconductor substrate110coated with a photoresist material, as described above.

As further shown inFIG.10, process1000may include exposing the semiconductor substrate to light generated by an EUV radiation source using a pre-pulse laser beam, as described above (block1020). For example, the lithography system100may expose the semiconductor substrate110to light generated by the EUV radiation source (e.g., the radiation source102) using a pre-pulse laser beam120a, as described above. In some implementations, using the pre-pulse laser beam120aincludes receiving, by a controller502from a quad-cell sensor160, first data associated with the pre-pulse laser beam120aand receiving, by the controller502from a camera sensor162, second data associated with the pre-pulse laser beam120a. Additionally, or alternatively, using the pre-pulse laser beam120aincludes providing, by the controller502based on the first data and the second data, a signal708to cause an adjustment to a target position154of the pre-pulse laser beam120a, as described above.

In a first implementation, the first data corresponds to a first portion306aof a phase of a wavefront302of the pre-pulse laser beam120aand the second data corresponds to a second portion404aof the phase of the wavefront302the pre-pulse laser beam120a.

In a second implementation, alone or in combination with the first implementation, a first size of the first portion306aof the phase is less relative to a second size of the second portion404aof the phase.

In a third implementation, alone or in combination with one or more of the first and second implementations, the first portion306aof the phase is encompassed by the second portion404aof the phase.

In a fourth implementation, alone or in combination with one or more of the first through third implementations, the signal508to cause the adjustment to the target position154of the pre-pulse laser beam120ais to synchronize a first location of the pre-pulse laser beam120aand a second location of a droplet of a target material118atraversing a path156within a vessel112of the EUV radiation source102.

In a fifth implementation, alone or in combination with one or more of the first through fourth implementations, receiving the first data includes receiving the first data at a first frequency, and receiving the second data includes receiving the second data at a second frequency that is less than the first frequency.

In a sixth implementation, alone or in combination with one or more of the first through fifth implementations, the first frequency is in a first range from approximately 3 kilohertz to approximately 5 kilohertz and the second frequency is in a second range from approximately 22 hertz to approximately 26 hertz.

In a seventh implementation, alone or in combination with one or more of the first through sixth implementations, providing the signal508to cause the adjustment to the target position includes providing the signal to cause the adjustment to the target position to compensate for a drift in the target position that results from a thermal effect on a laser source that generates the pre-pulse laser beam.

In an eighth implementation, alone or in combination with one or more of the first through seventh implementations, providing the signal508to cause the adjustment to the target position154includes determining, based on the first data and the second data, to adjust an orientation of at least one mirror150bof a mirror system506controlling the target position154of the pre-pulse laser beam120a.

In a ninth implementation, alone or in combination with one or more of the first through eight implementations, process1000includes determining a correlation relating to an increase in an amount of EUV radiation provided by the EUV radiation source102based on the signal508to cause the adjustment, and providing information relating to the correlation to update a machine learning model that estimates the increase in the amount of EUV radiation based on the signal508to cause the adjustment.

AlthoughFIG.10shows example blocks of process1000, in some implementations, process1000includes additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted inFIG.10. Additionally, or alternatively, two or more of the blocks of process1000may be performed in parallel.

Techniques described herein provide an EUV radiation source using a dual-feedback control system to control and adjust a target position of a pre-pulse laser beam. In addition to using feedback from a high-frequency quad-cell sensor to adjust a target position of the pre-pulse laser beam based on a first portion of a phase of a wavefront of the pre-pulse laser beam, the dual-feedback control system uses feedback from a low-frequency camera sensor to adjust the target position of the pre-pulse laser beam based on a second portion of the phase of the wavefront. In this way, the EUV radiation source maintains an accurate target position of the pre-pulse laser beam to maintain a designated EUV radiation dose, a targeted yield rate or quality of semiconductor devices manufactured using the EUV radiation source, and/or an efficient use of the target material, among other examples.

As described in greater detail above, some implementations described herein provide a method. The method includes receiving, by a lithography system, a semiconductor substrate coated with a photoresist material. The method includes exposing, by the lithography system, the semiconductor substrate to light generated by an EUV radiation source using a pre-pulse laser beam. In some implementations, using the pre-pulse laser beam includes receiving, by a controller from a quad-cell sensor, first data associated with the pre-pulse laser beam and receiving, by the controller from a camera sensor, second data associated with the pre-pulse laser beam. In some implementations, the method includes providing, by the controller based on the first data and the second data, a signal to cause an adjustment to a target position of the pre-pulse laser beam.

As described in greater detail above, some implementations described herein provide a method. The method includes receiving, by a controller from a camera sensor, first data associated with a pre-pulse laser beam provided by a laser source. The method includes determining, by the controller based on a comparison of the first data and second data, that a target position of the pre-pulse laser beam has moved over a time duration. The method includes determining, by the controller based on determining that the target position of the pre-pulse laser beam has moved over the time duration, to adjust a calibration setting of a mirror system controlling the target position of the pre-pulse laser beam. The method includes providing, by the controller based on determining to adjust the calibration setting of the mirror system, a signal to the mirror system to cause an adjustment to the calibration setting, where the adjustment to the calibration setting is to cause the target position to align to a focus region in which a droplet of a target material is to be deformed by the pre-pulse laser beam.

As described in greater detail above, some implementations described herein provide a system. The system includes a radiation source configured to generate EUV light from a droplet of a target material. The system includes a mirror configured to redirect a laser beam from a laser source of the radiation source to a target position corresponding to a focus region. The system includes a quad-cell sensor configured to operate at a first frequency. The system includes a camera sensor configured to operate at a second frequency that is less than the first frequency. The system includes a controller configured to receive, from the quad-cell sensor at the first frequency, first data associated with the laser beam. The controller is configured to receive, from the camera sensor at the second frequency, second data associated with the laser beam. The controller is configured to determine, based on one or more of the first data or the second data, to adjust an orientation of the mirror to adjust the target position. The controller is configured to provide, based on determining to adjust the orientation of the mirror to adjust the target position, a signal to cause an adjustment to the orientation of the mirror to adjust the target position to align to the focus region.