Predictive control of pulsed light beams

Abstract

In some general aspects, a beam control device includes: a spectral feature actuator associated with a set of different states, each state configured to cause an optical device to generate one or more pulses of the beam with discrete values ​​of the spectral features of the beam; and a controller in communication with the spectral feature actuator. The controller includes: an actuator driving module configured to cause the spectral feature actuator to transition between the set of different states according to a control waveform; a waveform module configured to calculate a control waveform of the spectral feature actuator that governs the transition between the set of discrete values; and a prediction module configured to receive one or more sensed aspects of the spectral feature actuator and instruct the waveform module to adjust the control waveform based on the received sensed aspects.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Application No. 62 / 993,235, filed March 23, 2020, entitled Predicative Control of a Pulsedight Beam, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The disclosed subject matter relates to controlling spectral characteristics such as bandwidth or wavelength of a light beam output from an optical device that supplies light to a photolithography exposure apparatus. Background Technology

[0004] In semiconductor lithography (or photolithography), the fabrication of integrated circuits (ICs) requires performing various physical and chemical processes on a semiconductor (e.g., silicon) substrate (also known as a wafer). A photolithography exposure apparatus (also known as a scanner) is a machine that applies a desired pattern onto a target area of ​​the substrate. A pattern forming apparatus, alternatively called a mask or photomask, can be used to generate the desired pattern to be formed. The transfer of the pattern is typically accomplished by imaging onto a layer of radiation-sensitive material (resist) provided on the substrate.

[0005] The substrate is irradiated by a beam of light having a wavelength in the ultraviolet range, somewhere between visible light and X-rays, and therefore having a wavelength between approximately 10 nanometers (nm) and approximately 400 nm. Thus, the beam can have wavelengths in the deep ultraviolet (DUV) range, for example, having wavelengths that can fall between approximately 100 nm and approximately 400 nm, or wavelengths in the extreme ultraviolet (EUV) range, having wavelengths between approximately 10 nm and approximately 100 nm. These wavelength ranges are not precise, and there may be overlap between light being considered DUV and EUV. For example, DUV excimer lasers are commonly used to generate the beam. Examples of DUV excimer lasers include krypton fluoride (KrF) lasers with a wavelength of 248 nm and argon fluoride (ArF) lasers with a wavelength of 193 nm.

[0006] The light beam passes through the beam delivery unit, is filtered by a mask, and is then projected onto a prepared substrate. The relative position between the substrate and the beam moves within the image plane, and the process is repeated for each target area on the substrate. In this way, the chip design is patterned onto photoresist, which is then etched and cleaned, and the process is repeated. Summary of the Invention

[0007] In some general aspects, a beam control device includes: a spectral feature actuator associated with a set of different states, each state configured to cause an optical device to generate one or more beam pulses with discrete values ​​of the spectral features of the beam; and a controller communicating with the spectral feature actuator. The controller includes: an actuator driving module configured to cause the spectral feature actuator to transition between the set of different states according to a control waveform; a waveform module configured to calculate a control waveform of the spectral feature actuator governing the transition between the set of discrete values; and a prediction module configured to receive one or more sensed aspects of the spectral feature actuator and instruct the waveform module to adjust the control waveform based on the received sensed aspects.

[0008] The implementation may include one or more of the following features. For example, the beam control device may also include an actuator sensor configured to sense one or more aspects of a spectral feature actuator. The prediction module may communicate with the actuator sensor to receive the sensed aspects of the spectral feature actuator.

[0009] The controller can drive the spectral feature actuator between sets of different states at a frequency related to the pulse repetition rate requested by the photolithography exposure apparatus that receives the beam used to pattern the substrate. The controller can also drive the spectral feature actuator between sets of different states at a frequency greater than the pulse repetition rate, where the pulse repetition rate corresponds to the rate of one or more pulses of the generated beam.

[0010] The controller may include a lithography module that communicates with the lithography exposure apparatus and is configured to receive pulse repetition rates from the lithography exposure apparatus. The control waveform may be based on the pulse repetition rates received from the lithography exposure apparatus.

[0011] Each time a pulse is generated, the spectral signature actuator can be in one of different states, and the beam pulse can have spectral signatures corresponding to that different state.

[0012] The beam control device may further include a measuring device configured to sense the spectral characteristics of the beam. The controller may include a spectral characteristics module configured to receive the sensed spectral characteristics of the beam, analyze the sensed spectral characteristics, and instruct a waveform module to adjust the control waveform based on the analysis. The spectral characteristics module may be configured to analyze the sensed spectral characteristics using one or more of the following: proportional-integral-derivative control, model predictive control, and state feedback with a Kalman filter. The spectral characteristics module may be configured to analyze the sensed spectral characteristics by converting the sensed spectral characteristics into an estimated state of a spectral characteristics actuator, and then comparing the estimated state of the spectral characteristics actuator with the output of the control waveform.

[0013] A spectral signature actuator can communicate with at least one optical element of a spectral signature modulator of an optical device, the at least one optical element optically interacting with a light beam. Each different state of the spectral signature actuator can correspond to a discrete state of the optical element. The discrete state of the optical element can be a discrete position where the optical element optically interacts with the light beam. The optical element can include a prism through which the light beam passes. The spectral signature actuator can include at least a motor physically coupled to the prism, the operation of which causes the prism to rotate.

[0014] The spectral feature modulator may include: a dispersive optical element arranged to interact with a light beam; and a plurality of prisms arranged in the path of the light beam between the dispersive optical element and the output of the optical device. The optical element communicating with the spectral feature actuator may be at least one of a prism or a dispersive optical element.

[0015] The spectral characterizer can optically interact with the seed pulse beam, which is generated by the first gas discharge stage of the optical device.

[0016] The spectral characteristics of a light beam can be either its wavelength or its bandwidth.

[0017] The control waveform may include a periodic drive signal. The waveform module can be configured to adjust the control waveform by regulating one or more of its frequency and / or phase. The waveform module can be configured to calculate the control waveform based on: a pulse repetition rate determined according to a trigger output from the photolithography exposure apparatus receiving the beam; a target separation value, which lies between discrete values ​​of the beam's spectral characteristics; and a sensitivity metric indicating how much the beam's spectral characteristic values ​​change in response to changes in the spectral characteristic actuator.

[0018] The prediction module can be configured to analyze the sensed aspects received by the spectral signature actuator to determine instructions to the waveform module to adjust the control waveform. Analysis of the sensed aspects received by the spectral signature actuator can include one or more of proportional-integral-derivative control, model predictive control, and state feedback with a Kalman filter. The waveform module can adjust the control waveform by modifying the trajectory of the control waveform in real time. The prediction module can be configured to receive and analyze the sensed aspects of the spectral signature actuator at a rate at least two, three, or five times the frequency of the control waveform.

[0019] The control waveform allows the spectral signature actuator to cycle between discrete values ​​based on the state frequency. The prediction module can be configured to instruct the waveform module to adjust at an update frequency greater than the state frequency.

[0020] In other general aspects, a method includes: generating pulses of a light beam; simultaneously generating pulses, driving a spectral feature actuator between sets of different states according to a control waveform, each different state corresponding to a discrete value of a spectral feature of the light beam, such that each time a pulse is generated, the spectral feature actuator is in one of the different states, and the light beam pulse has a spectral feature corresponding to that different state; and between pulse generation, adjusting the control waveform based on one or more sensed aspects of the spectral feature actuator.

[0021] The implementation may include one or more of the following features. For example, the method may also include one or more aspects of a sensing spectral feature actuator. The method may also include receiving a pulse repetition rate from a photolithography apparatus positioned to receive generated beam pulses. The control waveform may include a periodic structure associated with the pulse repetition rate. The method may also include receiving sensed spectral features of the beam and adjusting the control waveform based on the received sensed spectral features.

[0022] The spectral characteristics of a light beam can be either its wavelength or its bandwidth.

[0023] The control waveform may include periodic drive signals.

[0024] The control waveform can be adjusted by regulating one or more of its frequency, amplitude, and phase. The control waveform can also be adjusted by modifying its trajectory in real time.

[0025] The method may also include calculating the control waveform based on one or more of the following: a pulse repetition rate determined by a trigger output from a photolithography exposure apparatus receiving the beam; a target separation value located between discrete values ​​of the spectral characteristics of the beam; and a sensitivity measure indicating how much the spectral characteristic values ​​of the beam change in response to a change in the spectral characteristic actuator.

[0026] The method may also include: analyzing one or more sensed aspects of the spectral characteristic actuator, including performing one or more of proportional-integral-derivative control, model predictive control, and state feedback with a Kalman filter. Attached Figure Description

[0027] Figure 1 It is a block diagram of a predictive control device, including an optical device for generating beam pulses for use by the device, a spectral feature actuator that interacts with the optical device, and a controller that communicates with the spectral feature actuator.

[0028] Figure 2 yes Figure 1 A block diagram of the implementation of the device, wherein the device is a photolithography exposure apparatus that receives a light beam generated by an optical device;

[0029] Figure 3A and Figure 3B They are shown separately. Figure 1 A block diagram of the first state and the second state of the spectral characteristic actuator;

[0030] Figure 4 yes Figure 1 An exemplary optical spectrum of the beam;

[0031] Figure 5 yes Figure 1 A block diagram illustrating the implementation of an optical device, wherein the optical device is a two-stage pulsed light source;

[0032] Figure 6 yes Figure 5 A block diagram illustrating the implementation of a spectral characterization modulator for a dual-stage pulsed light source, which is related to... Figure 1 Spectral characteristics of actuator communication;

[0033] Figure 7 yes Figure 6 A planar diagram of the implementation of the spectral feature modulator;

[0034] Figure 8A and Figure 8B They are shown separately. Figure 7 A plan view of the first and second states of the spectral feature actuator within the spectral feature modulator and the corresponding first and second states of the associated prism.

[0035] Figure 9 yes Figure 1 A block diagram illustrating the implementation of the predictive control device;

[0036] Figure 10 It shows that it is applied to Figure 9 A graph showing the relationship between the control waveform of the spectral feature actuator, the incoming trigger signal received from the photolithography exposure device, the beam pulse sequence generated by the optical device in response to the incoming trigger signal, and the actual state of the actuation system of the spectral feature modulator within the optical device.

[0037] Figure 11A Is applied to Figure 1 An example of the sinusoidal control waveform of the spectral characteristics actuator;

[0038] Figure 11B Is applied to Figure 1 An example of a square control waveform for a spectral characteristic actuator;

[0039] Figures 11C-11E It can be applied to Figure 1 Examples of modified, multi-shaped, or more complex control waveforms for spectral characteristic actuators;

[0040] Figure 12 It is by Figure 1 or Figure 9 A block diagram of the control structure implemented by the predictive control device; and

[0041] Figure 13 It is by Figure 1 or Figure 9 The flowchart shows the process of the predictive control device. Detailed Implementation

[0042] refer to Figure 1 The image shows a predictive control device 100. The predictive control device 100 includes an optical device 110 that generates pulses of a light beam 120 directed toward a device 130. Sometimes, it is desirable to alter the spectral characteristics (such as wavelength) of the light beam 120 as it is directed toward the device 130. The device 130 may require the wavelength of the light beam 120 to change with each pulse or group of pulses between separate or different sets of wavelengths. The pulses of the light beam 120 can be generated in the form of clusters or sets of pulses scattered over time when no pulses are generated. Such clusters or sets of pulses are called bursts. The clustering of pulses into bursts and the number of pulses within a burst can be governed by the requirements of the device 130.

[0043] refer to Figure 2 In some implementations, device 130 is a photolithography exposure apparatus 230 configured to apply a desired pattern to a target area of ​​substrate 231. The photolithography exposure apparatus 230 includes an optical arrangement 232 in the path of the incoming light beam 120, comprising, for example, one or more condenser lenses, a mask, and an objective lens arrangement. The mask is movable in one or more directions, such as along the optical axis OA of the light beam 120, or in a plane perpendicular to the optical axis OA of the light beam 120. The objective lens arrangement 232 includes a projection lens and photoresist that allows the image to be transferred from the mask onto the substrate 231.

[0044] The photolithography exposure apparatus 230 may require control of the beam 120 to enable multifocal imaging at the patterned substrate 231. When forming a three-dimensional (3D) or vertical NAND layer of memory on the substrate 231 (that is, a memory structure resembling NAND gates stacked on top of each other), the photolithography apparatus may require the wavelength of the beam 120 to change in a regular and periodic manner. Creating complex 3D structures on the substrate 231 is complex and requires extremely high precision, ultimately necessitating process uniformity and repeatability for scalability. Furthermore, as the height of multilayer stacks increases, the difficulty of achieving consistent etch and deposition results at the top and bottom of the stack (e.g., a memory array) also increases.

[0045] The fabrication of 3D NAND memory requires altering the depth of focus (DOF) at substrate 231. The lithographic depth of focus (DOF) is determined by the relationship DOF = ±mλ / (NA). 2 The wavelength of the illuminating light (beam 120) is determined, NA is the numerical aperture of the projection lens (within the photolithography exposure apparatus 230) as seen from the substrate 231, and m is a practical factor dependent on the resist process. Therefore, to obtain varying depths of focus, more than one exposure pass is performed over the substrate 231, using a different laser wavelength for each pass. Alternatively, the wavelength of the beam can be changed every few pulses, or on a pulse-to-pulse basis (i.e., with each pulse), to allow for better control of the depth of focus during a single pass. Furthermore, the material of the lenses constituting the optical arrangement 232 of the photolithography exposure apparatus 230 is dispersive, and therefore different wavelengths will focus at different depths within the substrate 231. This is another reason why it might be desirable to have the ability to change the wavelength of the beam 120.

[0046] For this purpose, the predictive control device 100 includes a spectral feature actuator 140 and a controller 150 communicating with the spectral feature actuator 140. The spectral feature actuator 140 is associated with a set of different states, each configured to cause the optical device 110 to generate one or more pulses of the beam 120 using discrete values ​​of the spectral features of the beam 120. For example, as... Figure 3A As shown, the spectral signature actuator 140 is in a first state 140S1 in which it emits a pulse of the beam 120, such a pulse having a first spectral signature SF1, and as Figure 3B As shown, the spectral feature actuator is in a second state 140S2 in which it emits a pulse of light beam 120, such a pulse having a second spectral feature SF2 that is different from the first spectral feature SF1.

[0047] The controller 150 includes an actuator drive module 152 configured to cause the spectral feature actuator 140 to transition between a set of different states (140Si) according to a control waveform 154. The actuator drive module 152 may be implemented as a field-programmable gate array. The controller 150 also includes a waveform module 156 configured to calculate or compute the control waveform 154 for the spectral feature actuator 140, which governs the transitions between the set of different states 140Si.

[0048] Even though the spectral signature actuator 140 transitions between sets of different states 140Si according to the control waveform 154, the spectral signature actuator 140 may not be in the correct state 140Si when the pulse of the beam 120 is generated, and therefore the pulse of the beam 120 may not be at the discrete value of the spectral signature SFi expected by the device 130. Instead, the pulse of the beam 120 may have an actual spectral signature value that is offset by an amount from the expected value SFi. Therefore, the predictive control device 100 provides a predictive correction for the beam 120 before outputting the beam 120 from the optical device 110. The predictive control device 100 uses the predictive correction to adjust the control waveform 154 in real time to take into account errors in the control waveform 154, disturbances or variations in the spectral signature actuator 140, and / or disturbances or variations in the optical device 110 during operation. Furthermore, this predictive correction does not require the controller 150 to wait to determine information about the beam 120 (which can only be determined after the beam 120 has been generated), although the controller 150 may additionally use feedback and predictive correction related to the beam 120, as discussed in detail below. When the device 130 requires multifocal imaging, the predictive control device 100 is thus able to improve the control of the wavelength of the beam 120.

[0049] The predictive correction is influenced by a controller 150, which receives information related to the state or properties of the spectral signature actuator 140. To this end, the controller 150 further includes a prediction module 158 configured to receive one or more sensed aspects of the spectral signature actuator 140. The prediction module 158 analyzes these sensed aspects and instructs the waveform module 156 to adjust the control waveform 154 based on the analysis.

[0050] See you again Figure 2 The lithography exposure apparatus 230 includes a stage or base 233 on which a substrate 231 is placed. The stage 233 is connected to a locator to accurately position the substrate 231 according to certain parameters. The lithography exposure apparatus 230 may also include a lithography controller 234, air conditioning equipment, and power supplies for various electrical components. The lithography controller 234 controls how layers are printed on the substrate 231 and can also control the positioning of the stage 233. The lithography controller 234 includes a memory storing information such as process recipes. The process recipe determines the exposure length on the substrate 231 based on, for example, the mask used and other factors that affect exposure. During lithography, multiple pulses of the beam 12 irradiate the same area of ​​the substrate 231 to constitute an irradiation dose.

[0051] refer to Figure 4The spectral characteristics of beam 120 can include any aspect of the representation associated with the optical spectrum 422 of beam 120. The optical spectrum 422 is depicted in graphical form, where the spectral intensity 423 (not necessarily with absolute calibration) is plotted as a function of wavelength or optical frequency 424. The optical spectrum 422 can be referred to as the spectral shape or intensity spectrum of beam 120. Thus, wavelength is a spectral characteristic and can be the value λmax of the optical spectrum 422 at its maximum intensity. As another example, bandwidth, as a measure of the width Δλ of the optical spectrum 422, is a spectral characteristic. Bandwidth can be the actual instantaneous bandwidth of the optical spectrum 422.

[0052] Typically, for use by the photolithography exposure apparatus 230, the light beam 120 has a wavelength in the deep ultraviolet (DUV) range, for example, a wavelength of approximately 248 nanometers (nm) or approximately 193 nm. It can be applied to the substrate 231 ( Figure 2 The minimum size of the patterned microelectronic feature on the beam 120 depends on the wavelength of the beam 120; a lower wavelength allows for a smaller minimum feature size. For example, if the wavelength of the beam 120 is 248 nm or 193 nm, the minimum size of the microelectronic feature can be 50 nm or less.

[0053] Refer again Figure 1 The controller 150 includes one or more of digital electronic circuitry, computer hardware, firmware, and software. Each of modules 152, 156, and 158 can be implemented in such digital electronic circuitry, hardware, firmware, or software. The controller 150 also includes memory that can be read-only memory and / or random access memory. Storage devices suitable for tangibly embodying computer program instructions and data include all forms of non-volatile memory, such as semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices; disks, such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM disks. The controller 150 may also include one or more input devices (such as a keyboard, touchscreen, microphone, mouse, handheld input device, etc.) and one or more output devices (such as speakers or monitors). The controller 150 also includes one or more programmable processors, and one or more computer program products tangibly embodied in machine-readable storage devices for execution by one or more programmable processors. The controller 150 may be centralized (where all components are located close to each other), or the various components of the controller 150 may be partially or wholly distributed throughout the predictive control device 100.

[0054] refer to Figure 5In some implementations, the optical device 110 is a two-stage pulsed light source 510 that generates a pulsed beam 520 as a beam 120. The light source 510 is a gas discharge light source that includes a seed stage 511 that generates a seed beam 515, an amplification stage 525 that amplifies the power of the seed beam 515 to generate an output beam 520 as a beam 120, a relay optical system 516, and an output system 517.

[0055] The seed stage 511 includes, for example, a master oscillator (MO) chamber 513 housing a gain medium, an optical output coupler 514, and a beam tuning arrangement 512. A window may be provided on the MO chamber 513 to allow a portion of the seed beam (referred to as the precursor beam 515p) to be passed to the beam tuning arrangement 512. The beam tuning arrangement 512 and the output coupler 514 form an oscillator cavity in which the seed stage 511 forms a seed beam 515. The beam tuning arrangement 512 may be designed as a spectral characteristic modulator, wherein one or more spectral characteristics of the seed beam 515 (and thus the output beam 520) can be tuned, as discussed in more detail below. The optical output coupler 514 may include a partial mirror.

[0056] The relay optics system 516 may include one or more optical elements configured to redirect the seed beam 515 toward the amplification stage 525. The relay optics system 516 may also include elements configured to modify aspects of the seed beam 515, such as lateral range or wavefront.

[0057] Amplification stage 525 can be designed, for example, as a power ring amplifier, which includes a power amplifier (PA) chamber 527 (containing a gain medium), a beam reverser 526, and an optical coupling system 528. Optical coupling system 528 may include partially reflective optics for coupling a seed beam 515 (from seed stage 511) into amplification stage 525 and coupling light out of amplification stage 525 as an output beam 520 (towards output system 517). The optical coupling system may also include one or more mirrors and prisms configured to operate at nominal operating spectral characteristics (e.g., wavelengths in the DUV range).

[0058] MO chamber 513 and PA chamber 527 are configured such that a discharge between the electrodes can induce a gas discharge in the gain medium to generate inserted high-energy molecular groups, including, for example, argon, krypton, and xenon.

[0059] The output system 517 may include one or more subsystems for adjusting various aspects of the output beam 520. For example, the output system 517 may include a meter or optical pulse stretcher for measuring the energy of the output beam 520.

[0060] Furthermore, the predictive control device 100 may also include a measurement system 519, which includes one or more measuring devices arranged at different locations within the light source 510. For example, the measurement system 519 may include one or more spectral feature analysis devices 518, 521, each configured to measure or sense spectral features associated with a light beam (such as a seed beam 515) generated within or output from the optical device 510 (such as a beam 520). One device 518 is a bandwidth analysis module located at or within the output of the optical device 510. The bandwidth analysis module 518 is configured to measure the bandwidth of the beam 520. Another device 521 is a wavelength analysis module located at or within the output of the optical device 510. In some implementations, the wavelength analysis module 521 is placed at the output of the seed beam 511. The wavelength analysis module 521 may include, for example, an etalon spectrometer providing fine wavelength measurements and a grating spectrometer providing coarse wavelength measurements.

[0061] As mentioned above, the beam tuning arrangement 512 can be designed as a spectral characteristic modulator, wherein one or more spectral characteristics of the seed beam 515 (and therefore the output beam 520) are modulated. Specifically, the tuning of the spectral characteristics of the output beam 520 is influenced by the tuning applied to the seed beam 515 by the spectral characteristic modulator 512. (See reference...) Figure 6 In some implementations, the spectral characterizer 512 is an optical arrangement 612 comprising multiple optical components or features, each of which interacts with a precursor beam 615p from the MO chamber 513. For example, the multiple optical components include optical features or components 641-1, 641-2, 641-3, 641-4, and 641-5 arranged to optically interact with the precursor beam 615p. The optical components of the optical arrangement 612 are all made of materials suitable for interacting with the precursor beam 615p having wavelengths in the DUV range.

[0062] In some implementations, optical component 641-5 is a dispersive optical element, such as a grating. Furthermore, optical components 641-1, 641-2, 641-3, and 641-4 are refractive optical elements, such as prisms, which together function as a beam expander / beam compressor. Grating 641-5 can be a reflective grating designed to disperse and reflect the beam 615p. And each of prisms 641-1, 641-2, 641-3, and 641-4 is a transmission prism, used to disperse and redirect the beam 615p as it passes through its body. Each prism can be made of a material that allows the wavelength of the beam 615p to be transmitted (such as, for example, calcium fluoride).

[0063] The light beam 615p enters the optical arrangement 612 through aperture 642, and then travels sequentially through prisms 641-1, 641-2, 641-3, and 641-4 before striking the diffraction surface of grating 641-5. With each pass of prisms 641-1, 641-2, 641-3, and 641-4, the beam 615p is optically magnified and redirected (refracted at an angle) toward the next optical component. The beam 615p is diffracted and reflected back from grating 641-5, passing sequentially through prisms 641-4, 641-3, 641-2, and 641-1, and then passes through aperture 642 as it leaves the optical arrangement 612 and returns to MO chamber 513. As the beam 615p travels from grating 641-5 through successive prisms 641-4, 641-3, 641-2, and 641-1, it is optically compressed as it travels toward aperture 642.

[0064] The rotation of any prism P in the optical arrangement 612 (where P is any one of 641-1, 641-2, 641-3, or 641-4) alters the angle of incidence of beam 615p striking the incident surface H(P) of the rotating prism P. Furthermore, the two local optical qualities of beam 615p through the rotating prism P, namely the optical magnification OM(P) and the beam refraction angle δ(P), are functions of the angle of incidence of beam 615p onto the incident surface H(P) of the rotating prism P. The optical magnification OM(P) of beam 615p through prism P is the ratio of the lateral width Wo(P) of beam 615p leaving prism P to the lateral width Wi(P) of beam 615p entering prism P. Changes in the local optical magnification OM(P) of beam 110A at one or more prisms P cause a global change in the optical magnification OM of beam 615p. Furthermore, the change in the local beam refraction angle δ(P) through one or more prisms P causes a global change in the incident angle Φ of beam 615p at the surface of grating 641-5. The wavelength of beam 615p can be adjusted by changing the incident angle Φ of beam 615p striking the diffraction surface of grating 641-5. The bandwidth of beam 615p can be adjusted by changing the optical magnification OM of beam 615p.

[0065] See Figure 7In some implementations, the spectral feature actuator 140 is a spectral feature actuator 740 associated with the spectral feature modulator 712 of the optical device 110. The spectral feature modulator 712 is designed such that prisms 741-1, 741-2, 741-3, 741-4 and grating 741-5 are arranged in a littrow configuration, wherein grating 741-5 is used such that the incident angle Φ of the beam 715p onto grating 741-5 is equal to the exit angle of the beam 715p from grating 741-5. In this example, grating 741-5 may be a high blaze angle echelle grating, and any incident angle Φ of the beam 715p incident on grating 741-5 satisfying the grating equation will be reflected (diffracted). By changing the incident angle Φ of the beam 715p onto grating 741-5, the wavelength of the beam 715p can be tuned across the entire gain bandwidth of the resonator within the optical device 510.

[0066] The spectral signature actuator 740 includes a control module 742, which comprises electronics in any combination of firmware and software. The control module 742 is connected to at least one actuation system 743-3 physically coupled to the prisms 741-3 and is configured to receive a control waveform 154 from the actuator drive module 152 of the controller 150. Although in Figure 7 Not shown, but the spectral feature actuator 740 may include other actuation systems physically coupled to other prisms, such as the actuation systems physically coupled to prism 741-4 and prism 741-1, which are controlled by the control module 742. Furthermore, additionally or alternatively, one or more of the gratings and prisms within the spectral feature modulator 712 may remain stationary or not physically coupled to the actuation system. For example, in some implementations, grating 741-5 may remain stationary and prism 741-2 may remain stationary and not physically coupled to the actuation system.

[0067] Actuation system 743-3 is a mechanical device for moving or controlling prism 741-3. Actuation system 743-3 receives energy from control module 742 and converts that energy into some kind of motion transmitted to prism 741-3. For example, actuation system 743-3 can be any of a force device for rotating prism 741-3 and a rotary table. Actuation system 743-3 may include, for example, a motor such as a stepper motor, a valve, a pressure control device, a piezoelectric device, a linear motor, a hydraulic actuator, or a voice coil.

[0068] In some implementations, the actuation system 743-3 includes a linear motor (e.g., including a piezoelectric transducer) physically coupled to a mechanical bending member, which is attached to a base on which the prism 741-3 is fixed. The linear motor converts signals from the control module 742 into linear translations applied to the mechanical bending member, resulting in rotational movement of the prism 741-3. In other implementations, the actuation system 743-3 includes a rotary motor physically coupled to the prism 741-3, and a piezoelectric motor that drives the rotary motor to rotate the prism 741-3. The rotation of the prism 741-3 changes the angle of incidence Φ of the beam 715p at the surface of the grating 741-5 (see [link to relevant documentation]). Figure 6 This modifies the wavelength of the light beam 715p (and thus modifies the wavelength of the light beam 715p output from the optical device 510). Therefore, and further referencing... Figure 8A and Figure 8B In this implementation, whenever the prism 741-3 is in a first rotation state 740S1, the spectral characteristic actuator 740 is in a first state, in which pulses of the beam 715p (and also the output beam 520) are emitted at a first wavelength λ1; and whenever the prism 741-3 is in a second rotation state 740S2, the spectral characteristic actuator 740 is in a second state, in which pulses of the beam 715p (and also the output beam 520) are emitted at a second wavelength λ2. More than two states are possible.

[0069] refer to Figure 9 The diagram illustrates an implementation 900 of the prediction control device 100. Similar to the prediction control device 100, the prediction control device 900 includes a controller 950 communicating with the spectral feature actuator 140. The controller 950 includes an actuator drive module 952, a waveform module 956, and a prediction module 958 (which respectively correspond to...). Figure 1 The actuator driving module 952, waveform module 156, and prediction module 158 are included. In the implementation of feeding data to the spectral feature actuator 140 at a very high rate, the actuator driving module 952 may include a field-programmable gate array (FPGA). Furthermore, the controller 950 communicates with the optical device 110 and the photolithography exposure device 230, and the prediction control device 900 includes additional components related to this communication, as follows.

[0070] The predictive control device 900 includes an actuator sensor 955 configured to sense one or more aspects of the spectral feature actuator 140. A prediction module 958 communicates with the actuator sensor 955 to receive, from the actuator sensor 955, the sensed aspects of the spectral feature actuator 140. In some implementations, the actuator sensor 955 senses the actual position of an optical element 941 within the spectral feature modulator 912, which is modified to alter the spectral characteristics of the beam 920. For example, the actuator sensor 955 may be configured to sense the actual position or state of prisms 641-3 or 741-3. In other implementations, the actuator sensor 955 is configured to sense the state or position of an actuation system physically coupled to the prism within the spectral feature actuator 140. For example, the actuator sensor 955 may be configured to sense the state or physical aspect of the actuation system 743-3. The actuator sensor 955 can be any sensing device that achieves this determination, such as, for example, an optical rotary encoder, a capacitive position sensor, a potentiometer, or a strain gauge that provides angular position feedback.

[0071] The predictive control device 900 includes a measurement system 919, similar to measurement system 519, comprising one or more measuring devices, each configured to measure or sense the spectral characteristics of a light beam within or output from optical device 110. Thus, in the implementation where controller 950 controls the wavelength of light beam 120 to transition between multiple discrete values, controller 950 receives information from a wavelength analysis module (such as module 521) within measurement system 919, which is configured to output sensed values ​​of the wavelength of light beam 920. For this purpose, controller 950 also includes a spectral characterization module 951, configured to receive and analyze the sensed wavelength from measurement system 919, as discussed below.

[0072] The controller 950 also includes a lithography module 953 that communicates with the lithography exposure apparatus 230. For example, the lithography module 953 can receive information and instructions from the lithography controller 234. The controller 950 also includes a light source module 957, which can be configured to instruct the optical apparatus 110 to generate pulses of the beam 920 based on information or analysis from any one or more other modules within the controller 950. For example, the light source module 957 can send trigger signals to one or more energy sources (such as electrodes) in the MO and PA chambers of the optical apparatus 510 to cause the optical apparatus 510 to generate the beam 520, such output trigger signals being based on incoming trigger signals received from the lithography module 953.

[0073] See Figure 10 The control waveform 154 is a periodic drive signal 1054 that governs the trajectory of the actuation system (such as the actuation system 743-3 which is physically coupled to the prism 741-3). Figure 10Also shown is an incoming trigger signal 1064 received at the lithography module 953 from the lithography controller 234 of the lithography exposure apparatus 230. The trigger signal 1064 comprises a set of trigger pulses, each trigger pulse instructing the optics 110 to generate a pulse of the beam 920. In various scanner-source arrangements, the timing between the trigger pulses indicates the pulse repetition rate requested by the scanner. Figure 10 Also shown is a pulse sequence 1062 of the light beam 120 generated by the optical device 110 (under the control of the light source module 957) in response to the incoming trigger signal 1064. The actual state of the actuation system 743-3 is represented by waveform 1060.

[0074] The control waveform 1054 can be any waveform that ensures the prism 741-3 is in the desired position or state while generating pulses of beam 515p (and 715p) from the seed stage 511.

[0075] The drive signal 1054 shown in this example has a triangular and continuous form. However, the drive signal 1054 is not limited to this shape. The drive signal 1054 can be any shape that continuously drives or modifies the actuation system through various positions or states, causing the spectral feature actuator 140 to exist at different times in one of a plurality of target discrete states (e.g., initial state 1040S1 and second state 1040S2). The desired motion of the spectral feature actuator 140 is to synchronize the placement of the spectral feature modulator 912 (e.g., prisms 741-3) in the desired position or state with the generation of pulses in the sequence 1062 of the beam 120 from the optical device 110. Figure 10 In the illustrated example, the spectral characteristic modulator 912 alternates between two states based on pulse-by-pulse switching. For example, this modulation could be used to achieve pulse-by-pulse switching between two wavelengths of the beam 920.

[0076] Other examples of control waveform 154 are in Figures 11A-11E As shown in [the image]. Figure 11A In the diagram, control waveform 1154A is a sine wave. Figure 11B In the diagram, control waveform 1154B is a square wave. Modified, multi-shaped, or more complex waveforms 1154C, 1154D, and 1154E are respectively... Figures 11C-11E As shown in the image.

[0077] refer to Figure 12A block diagram of the control structure 1260 is shown. The control structure 1260 is divided into two parts based on the frequency at which data is received and / or updated. The first and slower control part 1261 includes a reference generator 1262 within the waveform module 956. The reference generator 1262 receives data at a rate lower than the rate at which the pulses generating the beam 920 are produced (and therefore lower than the repetition rate of the optical device 110). For example, the reference generator 1262 can be configured to receive and manipulate data once for each pulse burst of the beam 920. The reference generator 1262 receives the data and, based on that data, calculates a reference trajectory R(t) or a desired baseline trajectory that governs how the spectral feature actuator 140 is adjusted.

[0078] exist Figure 12 In the implementation shown, reference generator 1262 receives a set of data 1263, 1264, and 1265. Data 1263 corresponds to the pulse repetition rate (“Ω”) 230 determined based on the trigger signal 1064 received from the photolithography exposure apparatus (see [link]). Figure 9 and Figure 10 Data (Ω) 1263 can be transmitted from the lithography module 953 to the waveform module 956 for analysis by the reference generator 1262. Data 1264 corresponds to a target spectral feature interval value (“Δ”). For example, if the spectral feature is wavelength, then this interval value Δ is the difference between two discrete desired wavelengths for the beams 120 / 920. This target wavelength interval value Δ can be determined based on information from the lithography exposure apparatus 230. For example, the target wavelength interval value Δ can be determined based on the process recipe received by the lithography module 953. Data 1265 corresponds to a sensitivity measure Π, which indicates how much the value of the spectral feature (such as wavelength) of the beam 920 changes in response to a change in the spectral feature actuator 140. The sensitivity measure Π can be a calibration amount determined before the start of operation of the optics apparatus 110. For example, the sensitivity measure Π can be determined by scanning the spectral feature actuator 140 in a known manner and measuring the actual value of the spectral feature output from the measurement system 919 to determine how the beam 920 changes in response to changes in the spectral feature actuator 140.

[0079] In some implementations, the reference generator 1262 calculates the reference trajectory R(t) according to the following equation:

[0080]

[0081] In this equation, the value of Ω / 2 corresponds to the frequency of the reference trajectory waveform, and the value of Δ / (2×Π) corresponds to the amplitude (amplitude or intensity) of the reference trajectory waveform.

[0082] If the other parts of the control structure 1260 are not adjusted, then the control waveform 954 is directly based on and corresponds to the reference trajectory R(t). That is, if the operation of the spectral feature actuator 140 is free from external interference and the control operates according to the model, then causing the spectral feature actuator 140 to transition according to the reference trajectory R(t) will be sufficient to generate pulses of the desired discrete wavelength beam 920.

[0083] However, the operation of the spectral feature actuator 140 and the optical device 110 is not perfect, and the mismatch between the modeled reference trajectory R(t) and the actual movement of the spectral feature actuator 140, as well as the interference with the spectral feature actuator 140 and the optical device 110, introduces errors into the control structure that will be based solely on the output from the reference generator 1262.

[0084] Therefore, the control structure 1262 includes a faster control section 1266, which includes feedback control 1267. Feedback control 1267 is implemented by two different overlapping controls, carried out by the spectral feature module 951 and the prediction module 958.

[0085] Feedback control 1267, implemented by spectral feature module 951, receives and analyzes the sensed wavelength of beam 920 from measurement system 919. This data can be received at a rate corresponding to the repetition rate Ω indicated by photolithography exposure apparatus 230. Therefore, each time a pulse of beam 920 is generated, spectral feature module 951 can receive the sensed wavelength of beam 920. Feedback control 1267 can use sensitivity metric Π to convert the measured or sensed value of the wavelength of beam 920 into an estimate of the position of spectral feature actuator 140. As discussed above, sensitivity metric Π indicates how much the wavelength value of beam 920 changes in response to a change in the position of spectral feature actuator 140. Therefore, spectral feature module 951 can divide the measured wavelength value by sensitivity metric Π to obtain an estimate of the position of spectral feature actuator 140.

[0086] The spectral characterization module 951 compares the estimated position of the spectral characterization actuator 140 with the value of the reference trajectory R(t) at that time point. Based on this analysis, the spectral characterization module 951 determines whether the reference trajectory R(t) needs adjustment. The analysis and determination can be performed according to any suitable control process, such as, for example, proportional-integral-derivative control, model predictive control, and state feedback with a Kalman filter.

[0087] The spectral characterization module 951 can control or influence changes to the reference trajectory R(t) by sending instructions to the waveform module 956 to adjust one or more of the amplitude, frequency, and phase of the reference trajectory R(t). For example, if there is a timing variation between the actuation applied by the spectral characterization actuator 140 and a pulse event occurring in the optical device 110, and this variation is not captured in the model used to calculate the control waveform R(t) in the control structure 1262, then this variance may cause a deviation in the actual wavelength interval value Δactual, and this deviation can be identified by the spectral characterization module 951. Therefore, the spectral characterization module 951 can attempt to adjust the control waveform R(t) to compensate for this deviation or the error in comparing it with the target wavelength interval value Δ. Depending on the type of control strategy being implemented, proportional-integral-derivative (PID) control can attempt to modulate the amplitude of the control waveform R(t) to reduce the error in the wavelength interval value (i.e., the difference between the actual wavelength interval value Δactual and the target wavelength interval value Δ). Another control strategy that can be implemented by the spectral feature module 951 is a Kalman filter with state feedback, which can attempt to adjust one or more of the phase and amplitude of the control waveform R(t).

[0088] Feedback control 1267, implemented by prediction module 958, receives the measured aspect (e.g., position) of spectral feature actuator 140 from actuator sensor 955. This data can be received at a rate greater than the pulse repetition rate Ω. Therefore, prediction module 958 can receive the measured position of spectral feature actuator 140 multiple times during the transition of spectral feature actuator 140 from a first state to a second state. For example, the measured position of spectral feature actuator 140 can be received at a rate of at least two, at least five, or ten times the pulse repetition rate Ω.

[0089] The error or difference between the measured position and the reference trajectory R(t) of the spectral signature actuator 140 can be evaluated using any suitable control, such as any servo control technique, proportional-integral-derivative (PID) control, model predictive control, or state feedback with a Kalman filter, which can provide better performance in predictive tracking and disturbance suppression.

[0090] The control waveform 954 can be adjusted based on the evaluation to ensure that the actual trajectory of the spectral characteristic actuator 140 is controlled in such a way that the next pulse of the beam 920 is generated at the target wavelength.

[0091] See Figure 13Process 1370 is executed by controller 950. Process 1370 begins with the start of a pulse burst

[1371] . Waveform module 956 calculates control waveform R(t) 954

[1372] . For example, waveform module 956 receives pulse repetition rate Ω, target spectral characteristic interval value Δ, and sensitivity measure Π, and performs this to calculate reference trajectory R(t) as a function of time.

[0092] A dynamic model of the spectral signature actuator 140 can be used to calculate the control waveform R(t)

[1372] to minimize the difference between the actual wavelength of the beam 920 and the target wavelength. For example, dynamic programming can be used to calculate the control waveform R(t), which is well-suited for handling complex models involving nonlinear dynamics. If a dynamic model of the spectral signature actuator 140 with strong nonlinear dynamics is employed, then dynamic programming can be used to generate a control signal R(t) for a given wavelength target. However, dynamic programming does present a challenge requiring significant computational resources. To overcome this challenge, data storage devices, such as pre-filled lookup tables or pre-programmed field-programmable gate arrays (FPGAs), can be used, containing optimal control parameters for at least some different repetition rates that can operate the optical device 110.

[0093] As another example, model-inverted feedforward control can be used to compute the control waveform R(t)

[1372] . This method relies on a dynamic model of the spectral characteristic actuator 140 to construct a digital filter that inverts the actuator dynamics. By passing the desired waveform of the desired actuator trajectory through this filter, the control waveform R(t) can be generated in real time to achieve zero steady-state error tracking.

[0094] As another example, a learning algorithm can be used to compute the control waveform R(t)

[1372] to ensure that the error converges over several learning iterations.

[0095] The control waveform R(t) can potentially achieve two separate wavelengths separated by 1000 femtometers (fm) with an interval error of less than 20 fm.

[0096] As another example, a combination of feedforward control and iterative learning control (ILC) can be used to compute the control waveform R(t)

[1372] .

[0097] In some implementations, constrained quadratic programming

[1372] can be used in the computation to help find the optimal feedforward signal within the feasible operating region.

[0098] If the controller 950 receives a trigger pulse (such as from trigger signal 1064)

[1373] , then the controller 950 (via actuator drive module 952) instructs the spectral characteristic actuator 140 to operate according to the reference trajectory R(t)

[1374] . The controller 950 also instructs the optical device 110 (via light source module 957) to begin generating pulses of the beam 920.

[0099] The controller 950 (via the spectral feature module 951) receives the sensed wavelength of the next pulse of the beam 920 from the wavelength analysis module of the measurement system 919

[1375] , and the spectral feature module 951 analyzes the sensed wavelength, as discussed above, to determine whether the measured spectral feature is within an acceptable range

[1376] . If the spectral feature module 951 determines that the measured spectral feature is outside the acceptable range

[1376] , then the waveform module 956 is instructed to adjust the control waveform 954

[1377] . For example, the waveform module 956 may adjust one or more of the amplitude, frequency, and phase of the reference trajectory R(t).

[0100] Next, the controller 950 (via the prediction module 958) receives one or more aspects sensed by the spectral signature actuator 140 from the actuator sensor 955

[1378] and analyzes this information (as discussed above) to determine whether the spectral signature actuator 140 is in the desired state

[1379] . If the prediction module 958 determines that the spectral signature actuator 140 is not in the desired state

[1379] , then it instructs the waveform module 956 to adjust the control waveform 954 by, for example, adjusting one or more of the amplitude, frequency, and phase of the reference trajectory R(t)

[1380] .

[0101] As long as no next trigger pulse has been received

[1381] and it is not a sudden end

[1382] , the program returns to step 1378, where controller 950 (via prediction module 958) receives one or more sensed aspects of spectral feature actuator 140 from actuator sensor 955

[1378] . As discussed above, this cycle (steps 1378-1382) can be performed several times between the generation of two pulses of beam 920.

[0102] Other aspects of the invention are set forth in the following numbered clauses.

[0103] 1. A beam control device, comprising:

[0104] A spectral signature actuator, associated with a set of different states, each configured to cause the optical device to generate one or more pulses of the beam using discrete values ​​of the spectral signature of the beam; and

[0105] The controller communicates with the spectral signature actuator and includes:

[0106] An actuator driving module is configured to cause the spectral characteristic actuator to transition between different sets of states according to the control waveform;

[0107] The waveform module is configured to calculate the control waveform of the spectral characteristic actuator, the control waveform governing the transitions between discrete values; and

[0108] A prediction module is configured to receive one or more sensed aspects from a spectral feature actuator and instruct the waveform module to adjust a control waveform based on the received sensed aspects.

[0109] 2. The beam control device according to Clause 1 further includes an actuator sensor configured to sense one or more aspects of a spectral feature actuator, wherein the prediction module communicates with the actuator sensor to receive the sensed aspects of the spectral feature actuator.

[0110] 3. The beam control device according to Clause 1, wherein the controller drives the spectral feature actuator at a frequency between sets of different states, the frequency being related to the pulse repetition rate required by the photolithography exposure apparatus that receives the beam for patterning the substrate.

[0111] 4. The beam control device according to Clause 1, wherein the controller drives the spectral feature actuator between sets of different states at a frequency greater than the pulse repetition rate, the pulse repetition rate corresponding to the rate of one or more pulses that generate the beam.

[0112] 5. The beam control device according to Clause 1, wherein the controller includes a lithography module that communicates with and is configured to receive a pulse repetition rate from the lithography exposure apparatus, wherein the control waveform is based on the pulse repetition rate received from the lithography exposure apparatus.

[0113] 6. The beam control device according to Clause 1, wherein each time a pulse is generated, the spectral feature actuator is in one of different states, and the beam pulse has a spectral feature corresponding to the different state.

[0114] 7. The beam control device according to Clause 1 further includes a measuring device configured to sense spectral characteristics of the beam, wherein the controller includes a spectral characteristic module configured to receive the sensed spectral characteristics of the beam, analyze the sensed spectral characteristics, and instruct a waveform module to adjust a control waveform based on the analysis.

[0115] 8. The beam control device according to Clause 7, wherein the spectral feature module is configured to analyze the sensed spectral features using one or more of the following: proportional-integral-derivative control, model predictive control, and state feedback with a Kalman filter.

[0116] 9. The beam control device according to Clause 7, wherein the spectral feature module is configured to analyze the sensed spectral features by converting the sensed spectral features into an estimated state of the spectral feature actuator and then comparing the estimated state of the spectral feature actuator with the output of the control waveform.

[0117] 10. The beam control device according to Clause 1, wherein the spectral feature actuator communicates with at least one optical element of the spectral feature adjuster of the optical device, the at least one optical element optically interacting with the beam.

[0118] 11. The beam control device according to Clause 10, wherein each different state of the spectral characteristic actuator corresponds to a discrete state of the optical element.

[0119] 12. The beam control device according to Clause 11, wherein the discrete states of the optical elements are discrete positions in which the optical elements interact optically with the beam.

[0120] 13. The beam control device according to Clause 10, wherein the optical element includes a prism through which the beam passes.

[0121] 14. The beam control device according to Clause 13, wherein the spectral feature actuator includes at least a motor physically coupled to the prism, the operation of which causes the prism to rotate.

[0122] 15. The beam control device according to Clause 10, wherein the spectral feature modulator comprises:

[0123] Dispersive optical elements are arranged to interact with the light beam; and

[0124] Multiple prisms are arranged in the path of the beam between the dispersive optical element and the output of the optical device.

[0125] The optical element that communicates with the spectral feature actuator is at least one of a prism or a dispersive optical element.

[0126] 16. The beam control device according to Clause 10, wherein the spectral feature modulator optically interacts with a seed pulse beam generated by a first gas discharge stage of the optical device.

[0127] 17. The beam control device according to Clause 1, wherein the spectral characteristics of the beam are the wavelength or bandwidth of the beam.

[0128] 18. The beam control device according to Clause 1, wherein the control waveform includes a periodic drive signal.

[0129] 19. The beam control device according to Clause 1, wherein the waveform module is configured to: adjust the control waveform by adjusting one or more of the frequency and / or phase of the control waveform.

[0130] 20. The beam control device according to Clause 1, wherein the waveform module is configured to calculate the control waveform based on:

[0131] The pulse repetition rate is determined based on the trigger output from the photolithography exposure device that receives the light beam;

[0132] The target separation value lies between discrete values ​​of the beam's spectral characteristics; and

[0133] A sensitivity metric that indicates how much the value of the spectral characteristics of a beam changes in response to a change in the spectral characteristics actuator.

[0134] 21. The beam control device according to Clause 1, wherein the prediction module is configured to analyze the sensed aspects received by the spectral feature actuator to determine instructions to the waveform module to adjust the control waveform, wherein the analysis of the sensed aspects received by the spectral feature actuator includes one or more of proportional-integral-derivative control, model predictive control, and state feedback with a Kalman filter.

[0135] 22. The beam control device according to Clause 21, wherein the waveform module adjusts the control waveform by modifying the trajectory of the control waveform in real time.

[0136] 23. The beam control device according to Clause 21, wherein the prediction module is configured to receive and analyze the sensed aspects of the spectral feature actuator at a rate of at least two, at least three, or at least five times the frequency of the control waveform.

[0137] 24. The beam control device according to Clause 1, wherein the control waveform causes the spectral feature actuator to cycle between discrete values ​​according to the state frequency, and the prediction module is configured to indicate the adjustment of the waveform module at an update frequency greater than the state frequency.

[0138] 25. A method comprising:

[0139] Pulses that generate a light beam;

[0140] While generating pulses, a spectral characteristic actuator is driven between sets of different states according to a control waveform. Each different state corresponds to a discrete value of the spectral characteristics of the beam, such that the spectral characteristic actuator is in one of the different states each time a pulse is generated, and the beam pulse has spectral characteristics corresponding to that different state; and

[0141] Between pulse generation, the control waveform is adjusted based on one or more sensed aspects of the spectral signature actuator.

[0142] 26. The method described in accordance with Clause 25 further includes one or more aspects of the sensing spectral feature actuator.

[0143] 27. The method according to Clause 25 further includes receiving a pulse repetition rate from a photolithography apparatus positioned to receive generated beam pulses, wherein the control waveform includes a periodic structure associated with the pulse repetition rate.

[0144] 28. The method according to Clause 25 further includes receiving sensed spectral characteristics of the light beam and adjusting the control waveform based on the received sensed spectral characteristics.

[0145] 29. The method according to Clause 25, wherein the spectral characteristics of the light beam are the wavelength or bandwidth of the light beam.

[0146] 30. The method according to Clause 25, wherein the control waveform includes a periodic drive signal.

[0147] 31. The method according to Clause 25, wherein adjusting the control waveform based on one or more sensed aspects of the spectral characteristic actuator comprises: adjusting one or more of the frequency, amplitude, and phase of the control waveform.

[0148] 32. The method according to Clause 25 further includes calculating the control waveform based on one or more of the following:

[0149] The pulse repetition rate is determined based on the trigger output from the photolithography exposure device that receives the light beam;

[0150] The target separation value lies between discrete values ​​of the beam's spectral characteristics; and

[0151] A sensitivity metric that indicates how much the value of the spectral characteristics of a beam changes in response to a change in the spectral characteristics actuator.

[0152] 33. The method according to Clause 25 further comprises: analyzing one or more sensed aspects of the spectral characteristic actuator, including performing one or more of proportional-integral-derivative control, model predictive control, and state feedback with a Kalman filter.

[0153] 34. The method according to Clause 25, wherein adjusting the control waveform based on one or more sensed aspects of the spectral signature actuator comprises: modifying the trajectory of the control waveform in real time.

[0154] Other implementations are within the scope of the following claims.

Claims

1. A beam control device, comprising: A spectral feature actuator, which is associated with a set of different states, each state being configured to cause the optical device to generate one or more pulses of the light beam with discrete values ​​of the spectral features of the light beam; as well as A controller, which communicates with the spectral signature actuator, includes: An actuator driving module is configured to cause the spectral feature actuator to transition between sets of different states according to a control waveform; A waveform module configured to calculate the control waveform of the spectral signature actuator, the control waveform governing transitions between the set of discrete values; and A prediction module is configured to receive one or more sensed aspects of the spectral feature actuator and instruct the waveform module to adjust the control waveform using prediction correction based on the received sensed aspects before the light beam is output from the optical device.

2. The beam control apparatus of claim 1 further includes an actuator sensor configured to sense one or more aspects of the spectral feature actuator, wherein the prediction module communicates with the actuator sensor to receive the sensed aspects of the spectral feature actuator.

3. The beam control device of claim 1, wherein the controller drives the spectral feature actuator at a frequency between the set of different states such that the frequency is related to the pulse repetition rate required by the photolithography exposure apparatus for receiving the beam for patterning the substrate.

4. The beam control apparatus of claim 1, wherein the controller drives the spectral feature actuator between sets of different states at a frequency greater than the pulse repetition rate, the pulse repetition rate corresponding to the rate of the one or more pulses that generate the beam.

5. The beam control apparatus of claim 1, wherein the controller includes a lithography module that communicates with and is configured to receive a pulse repetition rate from the lithography exposure apparatus, wherein the control waveform is based on the pulse repetition rate received from the lithography exposure apparatus.

6. The beam control device according to claim 1, wherein each time a pulse is generated, the spectral feature actuator is in one of the different states, and the beam pulse has spectral features corresponding to the different states.

7. The beam control apparatus of claim 1 further includes a measuring device configured to sense spectral characteristics of the beam, wherein the controller includes a spectral characteristic module configured to receive the sensed spectral characteristics of the beam, analyze the sensed spectral characteristics, and instruct the waveform module to adjust the control waveform based on the analysis.

8. The beam control device of claim 7, wherein the spectral feature module is configured to analyze the sensed spectral features using one or more of the following: proportional-integral-derivative control, model predictive control, and state feedback with a Kalman filter.

9. The beam control device of claim 7, wherein the spectral feature module is configured to analyze the sensed spectral features by converting the sensed spectral features into an estimated state of the spectral feature actuator and then comparing the estimated state of the spectral feature actuator with the output of the control waveform.

10. The beam control device of claim 1, wherein the spectral feature actuator communicates with at least one optical element of the spectral feature adjuster of the optical device, the at least one optical element optically interacting with the beam.

11. The beam control device of claim 10, wherein each different state of the spectral feature actuator corresponds to a discrete state of the optical element.

12. The beam control device according to claim 11, wherein the discrete state of the optical element is a discrete position in which the optical element interacts optically with the beam.

13. The beam control device of claim 10, wherein the optical element comprises a prism through which the beam passes.

14. The beam control device of claim 13, wherein the spectral feature actuator comprises at least a motor physically coupled to the prism, the operation of which causes the prism to rotate.

15. The beam control device according to claim 10, wherein the spectral feature modulator comprises: Dispersive optical elements are arranged to interact with the light beam; as well as Multiple prisms are arranged in the path of the light beam between the dispersive optical element and the output of the optical device. The optical element communicating with the spectral feature actuator is at least one of the prism or the dispersive optical element.

16. The beam control device of claim 10, wherein the spectral feature modulator optically interacts with the seed pulse beam, the seed pulse beam being generated by a first gas discharge stage of the optical device.

17. The beam control device according to claim 1, wherein the spectral characteristics of the beam are the wavelength or bandwidth of the beam.

18. The beam control device according to claim 1, wherein the control waveform includes a periodic drive signal.

19. The beam control device according to claim 1, wherein the waveform module is configured to: adjust the control waveform by adjusting one or more of the frequency and / or phase of the control waveform.

20. The beam control device of claim 1, wherein the waveform module is configured to calculate the control waveform based on: Pulse repetition rate, which is determined based on a trigger output from a photolithography exposure apparatus that receives the light beam; Target separation value, the target separation value being located among the discrete values ​​of the spectral characteristics of the beam; and A sensitivity metric, which indicates how much the value of the spectral characteristics of the light beam changes in response to a change in the spectral characteristic actuator.

21. The beam control apparatus of claim 1, wherein the prediction module is configured to analyze the sensed aspect received by the spectral feature actuator to determine instructions to the waveform module to adjust the control waveform, wherein the analysis of the sensed aspect received by the spectral feature actuator includes one or more of proportional-integral-derivative control, model predictive control, and state feedback with a Kalman filter.

22. The beam control device according to claim 21, wherein the waveform module adjusts the control waveform by modifying the trajectory of the control waveform in real time.

23. The beam control apparatus of claim 21, wherein the prediction module is configured to receive and analyze the sensed aspect of the spectral feature actuator at a rate at least twice the frequency of the control waveform.

24. The beam control apparatus of claim 21, wherein the prediction module is configured to receive and analyze the sensed aspect of the spectral feature actuator at a rate at least three times the frequency of the control waveform.

25. The beam control apparatus of claim 21, wherein the prediction module is configured to receive and analyze the sensed aspect of the spectral feature actuator at a rate at least five times the frequency of the control waveform.

26. The beam control apparatus of claim 1, wherein the control waveform causes the spectral feature actuator to cycle between discrete values ​​according to a state frequency, and the prediction module is configured to indicate adjustment of the waveform module at an update frequency greater than the state frequency.

27. A method for beam control, the method comprising: Pulses that generate a light beam; While generating the pulse, a spectral feature actuator is driven between sets of different states according to the control waveform. Each different state corresponds to a discrete value of the spectral feature of the beam, such that each time a pulse is generated, the spectral feature actuator is in one of the different states, and the beam pulse has spectral features corresponding to that different state. as well as Between the generation of the pulses, the control waveform is adjusted using predictive correction based on one or more sensed aspects of the spectral characteristics actuator before the beam is output.

28. The method of claim 27, further comprising one or more aspects of sensing the spectral feature actuator.

29. The method of claim 27, further comprising receiving a pulse repetition rate from a photolithography apparatus, the photolithography apparatus being positioned to receive generated beam pulses, wherein the control waveform includes a periodic structure associated with the pulse repetition rate.

30. The method of claim 27, further comprising receiving sensed spectral features of the light beam and adjusting the control waveform based on the received sensed spectral features.

31. The method of claim 27, wherein the spectral characteristics of the light beam are the wavelength or bandwidth of the light beam.

32. The method of claim 27, wherein the control waveform comprises a periodic drive signal.

33. The method of claim 27, wherein adjusting the control waveform based on the one or more sensed aspects of the spectral signature actuator comprises: Adjust one or more of the frequency, amplitude, and phase of the control waveform.

34. The method of claim 27, further comprising calculating the control waveform based on one or more of the following: Pulse repetition rate, which is determined based on a trigger output from the photolithography exposure apparatus that receives the light beam; Target separation value, the target separation value being located among the discrete values ​​of the spectral characteristics of the beam; and A sensitivity metric, which indicates how much the value of the spectral characteristics of the light beam changes in response to a change in the spectral characteristic actuator.

35. The method of claim 27, further comprising: The one or more sensed aspects of the spectral characteristic actuator include performing one or more of proportional-integral-derivative control, model predictive control, and state feedback with a Kalman filter.

36. The method of claim 27, wherein adjusting the control waveform based on the one or more sensed aspects of the spectral signature actuator comprises: The trajectory of the control waveform is modified in real time.

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