Apparatus and method for wavelength control for multi-focal imaging

Abstract

An apparatus and method for performing multi-focal imaging in a semiconductor lithography system in which a wavelength switching assembly is inserted in the optical path of laser radiation between a fine wavelength control assembly and a coarse wavelength control assembly to vary the angle of incidence of the laser radiation on a diffraction grating.

Description

Cross-references in related fields

[0001] This application claims priority to U.S. Patent Application No. 63 / 613,215, filed December 21, 2023, entitled “APPARATUS FOR AND METHOD OF WAVELENGTH CONTROL FORMULTIFOCAL IMAGING”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to laser systems, such as excimer lasers that generate laser radiation, and systems and methods for controlling the wavelength of laser radiation. Background Technology

[0003] Photolithography equipment applies a desired pattern onto a substrate (such as a wafer of semiconductor material), typically onto a target portion of the substrate. Patterning devices (which can be masks or stencils) are used to generate circuit patterns to be formed on a single layer of the wafer. The transfer of the pattern is usually accomplished by imaging onto a layer of radiation-sensitive material (resist) provided on the substrate. Generally, a single substrate will contain adjacent target portions with consecutive patterning.

[0004] Photolithography equipment includes so-called steppers and scanners. In a stepper, each target area is irradiated by exposing the entire pattern to the target area at once. In a scanner, each target area is irradiated by scanning the pattern in a given direction ("scanning direction") with a radiation beam, while simultaneously scanning the substrate parallel or antiparallel to that direction. Alternatively, a pattern can be transferred from a patterning apparatus to a substrate by imprinting the pattern onto the substrate.

[0005] The light source used to illuminate the pattern and project it onto the substrate can be any of a variety of configurations. Commonly used deep ultraviolet (DUV) excimer lasers in photolithography systems include krypton fluoride (KrF) lasers that produce laser radiation with a center wavelength of 248 nm and argon fluoride (ArF) lasers that produce laser radiation with a center wavelength of 193 nm. Although these wavelengths are shorter than the wavelengths of the visible spectrum, this paper will refer to laser radiation at these wavelengths as "light".

[0006] Photolithography equipment can operate at a single wavelength, which can be referred to as monochromatic mode or single-focus imaging (SFI). However, for some applications, the ability to change the wavelength is desirable, that is, to operate in multi-color mode to control the depth of focus (DoF) of the laser beam. For example, in the fabrication of 3D NAND memory, NAND gate-like structures are stacked on top of each other, extending in a third dimension perpendicular to the xy plane of the 2D substrate. The transition from 2D to 3D NAND architecture requires significant changes in manufacturing processes, including the need for a larger DoF. The lithographic DoF is determined by the relationship between... The value is determined, where λ is the wavelength of the irradiated light, NA is the numerical aperture, and m2 is a factor that depends on the actual resist process. Due to the larger DoF requirement in 3D NAND lithography, more than one exposure pass is sometimes performed on the wafer, with each formation using a different laser wavelength.

[0007] In contrast to SFI, multifocal imaging (MFI) effectively increases the DoF of an objective with a given focal length (NA) by utilizing multiple focusing levels (e.g., focusing at different depths using multiple wavelengths). The material of the lens constituting the focused laser radiation is dispersive, so different wavelengths will focus at different depths. This technique can be specifically tuned to provide the required amount of wavelength spacing (peak spacing) for a particular DoF. This increases the imaging NA and exposure latitude (process window), while allowing the DoF to be optimized via MFI according to the manufacturing layer requirements.

[0008] As will be described in detail below, in the DUV laser system considered here, an optical sequence consisting of a series of modules modulates the pulses while transmitting them from where they are generated to where they are used. One module in the optical sequence is the linen narrowing module (LNM). The LNM consists of diffraction grating elements that act as wavelength-selective reflectors and includes optical prisms that refract the laser beam to adjust the angle of incidence and dispersion of the light on the grating, thereby controlling both the wavelength and bandwidth. In other words, within the LNM, laser radiation is reflected by the grating at a given angle to control the center wavelength and other spectral characteristics, such as the bandwidth or linewidth of the laser radiation. Each of the series of prisms positioned in the LNM is coupled to a corresponding electrically actuated element (EAE), which controls the position and / or orientation of the prism, which in turn affects the angle of incidence of the laser radiation on the grating. The prism may be a beam expander prism.

[0009] In a DUV laser system operating in monochromatic mode, two actuators (EAEs) work together to control the stability of the center wavelength. In this mode, an EAE with limited resolution, such as a stepper motor, is used, and an auxiliary EAE, such as a piezoelectric transducer (PZT), serves as the primary actuator for fine wavelength control. However, in dual-color mode, wavelength stability is based on the center or peak wavelength, i.e., the average of two alternating peaks, and in this mode, an oscillating prism within the LNM provides a wavelength shift synchronized with laser emission to generate laser pulses with the output wavelength alternating between the two values. In this arrangement, the auxiliary EAE's task is to generate the waveform of the alternating wavelengths. In some systems, this capability is achieved by altering the use of the optics for fine wavelength control, such that when operating a two-stage MFI in dual-color mode, the system loses its ability for fine wavelength control.

[0010] One challenge to the performance of systems like those just described is that the EAE attached to the prism responsible for wavelength shifting has a limited travel range. This, in turn, imposes a limitation on the achievable wavelength offset, i.e., the wavelength difference between two output wavelengths, known as the wavelength peak spacing. As mentioned above, such systems offer only a limited ability to control wavelengths, resulting in reduced wavelength stability. Such systems also exhibit inherently low efficiency due to the inherently low efficiency of LNMs, which limit the laser output power (laser energy per pulse).

[0011] It is against this backdrop that the need arose for the subject matter discussed in this article. Summary of the Invention

[0012] The following provides a brief overview of one or more embodiments to offer a basic understanding of them. This overview is not an extensive summary of all contemplated embodiments. It is not intended to identify any element of the embodiments as a key or essential element, nor does it depict the scope of any embodiment. Its sole purpose is to present some concepts of the embodiments in a concise form as a prelude to the more detailed description that follows.

[0013] According to one aspect of an embodiment, an apparatus may be disclosed comprising: a first wavelength control component arranged to receive and refract laser radiation; a wavelength switching component arranged to receive the laser radiation refracted by the first wavelength control component, the wavelength switching component having a first state and a second state, wherein in the first state the wavelength switching component deflects the laser radiation by the first amount, and in the second state the wavelength switching component deflects the laser radiation by the second amount, the wavelength switching component deflecting the laser radiation by the second amount; and a second wavelength control component arranged to receive and refract the laser radiation deflected by the wavelength switching component, wherein the laser radiation refracted by the second wavelength control component is guided to a diffraction grating, wherein the wavelength of the laser radiation diffracted by the diffraction grating depends on the incident angle of the laser radiation on the diffraction grating.

[0014] The first wavelength control component can be a fine wavelength control component, and the second wavelength control component can be a coarse wavelength control component. The first wavelength control component can be a coarse wavelength control component, and the second wavelength control component can include the fine wavelength control component. The first wavelength control component can include at least one prism. The second wavelength control component can include at least one prism.

[0015] The wavelength switching component may include a reflector. This reflector may include a planar reflector.

[0016] The wavelength switching component can correspond to a first angular position of the reflector, and the second state of the wavelength switching component can correspond to a second angular position of the reflector, which is different from the first angular position.

[0017] The device may also include an actuator mechanically coupled to the mirror, the actuator being configured to rotate the mirror between a first angular position and a second angular position in response to a control signal. The device may also include a controller for generating the control signal.

[0018] Laser radiation can be emitted in the form of one or more pulse trains, each pulse train consisting of multiple pulses, and in a first state, the wavelength switching component can make some pulses take a first value of dominant wavelength, and in a second state, it can make other pulses take a second value, which differs from the first value by the target dominant wavelength interval.

[0019] The wavelength switching assembly may include a mirror, and a first state of the wavelength switching assembly may correspond to a first angular position of the mirror, and a second state of the wavelength switching assembly may correspond to a second angular position of the mirror different from the first angular position. The wavelength switching assembly may include an actuator mechanically coupled to the mirror, the actuator being configured to rotate the mirror between the first angular position and the second angular position in response to a control signal.

[0020] The device may also include a controller adapted to generate control signals. The controller may be configured to cause the wavelength switching component to cause the dominant wavelength of the pulse to alternate pulse-by-pulse between a first value and a second value.

[0021] According to another aspect of one embodiment, a method is disclosed comprising: performing a first wavelength control operation on a pulse of laser radiation by refracting it using at least one first wavelength control prism to generate a refracted pulse of laser radiation; using a mirror to deflect the refracted pulse of laser radiation to generate a deflected pulse of laser radiation; performing a second wavelength control operation on the deflected pulse of laser radiation by refracting it using at least one prism to generate an additionally refracted pulse of laser radiation; and diffracting the additionally refracted pulse of laser radiation using a diffraction grating to generate a diffracted pulse of laser radiation, wherein the wavelength of the diffracted pulse of laser radiation depends on the angle of incidence of the additionally refracted pulse of laser radiation on the diffraction grating.

[0022] The first wavelength control operation can be a fine wavelength control operation, and the second wavelength control operation can be a coarse wavelength control operation.

[0023] Using a mirror to deflect a refracted laser radiation pulse to generate a deflected laser radiation pulse may include impinging the refracted laser radiation pulse onto the mirror and controlling the mirror to be in one of a first angular position or a second angular position different from the first angular position. Controlling the mirror to be in one of the first angular positions or a second angular position may also include an actuator mechanically coupled to the mirror, the actuator being configured to rotate the mirror between the first and second angular positions in response to a control signal. The method may also include generating a control signal.

[0024] According to another aspect of the embodiments, a method for generating laser output of a first wavelength or a second wavelength is disclosed, the method comprising generating laser radiation at a wavelength having a reference wavelength value, and controlling a mirror actuator to adjust the mirror angle of a mirror to offset the wavelength value of the laser radiation, thereby jittering between the first wavelength value and the second wavelength value.

[0025] The method may further include controlling a prism actuator to adjust the prism angle of the first prism, thereby adjusting the wavelength of the laser radiation. The mirror may be located in the optical path between the first and second prisms. The method also includes controlling a second prism actuator to adjust the second prism angle of the second prism to more coarsely adjust the wavelength of the laser radiation compared to the adjustment of the first prism.

[0026] According to another aspect of one embodiment, an apparatus is disclosed comprising: a diffraction grating in the optical path of a laser beam; a first prism in the optical path of the laser beam, movable to adjust the incident angle of the laser beam on the diffraction grating; a second prism in the optical path of the laser beam, movable to adjust the incident angle of the laser beam on the diffraction grating; and a reflector inserted in the optical path of the laser beam between the first and second prisms, the reflector rotating between a first position selecting a first incident angle of the laser beam on the diffraction grating and a second position selecting a second incident angle of the laser beam on the diffraction grating.

[0027] The first prism can be movable to finely adjust the incident angle of the laser beam on the diffraction grating, and the second prism can be movable to coarsely adjust the incident angle of the laser beam on the diffraction grating.

[0028] The device may also include a controller configured to move the first and second prisms based on feedback from a center wavelength detector that detects the center wavelength of the laser radiation. The controller may be configured to move the first and second prisms pulse by pulse.

[0029] The first and second prisms can be beam expanders.

[0030] According to another aspect of one embodiment, a method is disclosed, the method comprising: oscillating the rotational position of a reflector to change the incident angle of a laser radiation pulse on a grating pulse by pulse, thereby changing the laser radiation wavelength pulse by pulse between two set points; controlling a first prism to make a first adjustment to the incident angle of the laser radiation on the grating; and controlling a second prism to make a second adjustment to the incident angle of the laser radiation on the grating.

[0031] The first adjustment can be a fine-tuning adjustment, and the second adjustment can be a coarse-tuning adjustment.

[0032] According to another aspect of one embodiment, a non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform operations including: performing first wavelength control on a pulse of laser radiation by refracting it using at least one first wavelength control prism to generate a refracted pulse of laser radiation; using a mirror to deflect the refracted pulse of laser radiation to generate a deflected pulse of laser radiation; performing second wavelength control on the deflected pulse of laser radiation by refracting it using at least one second prism to generate an additionally refracted pulse of laser radiation; and diffracting the additionally refracted pulse of laser radiation using a diffraction grating to generate a diffracted pulse of laser radiation, wherein the wavelength of the diffracted pulse of laser radiation depends on the angle of incidence of the additionally refracted pulse of laser radiation on the diffraction grating.

[0033] Other features and exemplary aspects of the embodiments, as well as the structure and operation of various embodiments, are described in detail below with reference to the accompanying drawings. Note that the scope of all possible embodiments is not limited to the specific embodiments described herein. These specific embodiments given herein are for illustrative purposes only. Additional embodiments will be apparent to those skilled in the art based on the teachings contained herein. Attached Figure Description

[0034] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments and, together with the specification, further explain the principles of the embodiments, enabling those skilled in the art to make and use the embodiments.

[0035] Figure 1A , Figure 1B and Figure 1C This is a schematic diagram of a lithography apparatus according to an exemplary embodiment.

[0036] Figure 2A This is a schematic diagram of a light source device according to an exemplary embodiment.

[0037] Figure 2B This is a schematic diagram of a spectral feature actuation system according to an exemplary embodiment.

[0038] Figure 2C This is a schematic cross-sectional view of a line narrowing module according to an exemplary embodiment.

[0039] Figures 3A-3C This is a schematic diagram of a laser pulse train composed of laser pulses, illustrating some basic operating principles of one aspect of the embodiment.

[0040] Figure 4 This is a conceptual schematic diagram of a photolithography system according to one aspect of an embodiment.

[0041] Figure 5 This is a graph of a single-peak laser radiation spectrum generated according to one aspect of an embodiment.

[0042] Figure 6 This is a graph of the bimodal spectrum of laser radiation generated according to one aspect of an embodiment.

[0043] Figure 7A An example of a wavelength-shifted spectrum according to one aspect of an embodiment is shown.

[0044] Figure 7B This is a graph showing the relationship between inter-pulse wavelength and pulse number according to one aspect of an embodiment.

[0045] Figure 8 This is a schematic diagram of a system for performing wavelength adjustment and offset for MFI, according to one aspect of an embodiment.

[0046] Figure 9 This is a flowchart of a process for performing wavelength adjustment and offset for an MFI, according to one aspect of an embodiment.

[0047] Figure 10 This is a functional block diagram of a computer control system for controlling the system and / or executing the method, according to one aspect of an embodiment, for performing wavelength adjustment and offset for MFI.

[0048] The features and exemplary aspects of the embodiments will become more apparent when taken in conjunction with the accompanying drawings, based on the detailed description set forth below. In the drawings, the same reference numerals generally denote the same, functionally similar, and / or structurally similar elements. Unless otherwise stated, the drawings should not be construed as being drawn to scale. Detailed Implementation

[0049] The embodiments described in this specification and references to "an embodiment," "an embodiment," "an exemplary embodiment," "an example embodiment," etc., indicate that the described embodiments may include specific features, structures, or characteristics, but not every embodiment must include specific features, structures, or characteristics. Furthermore, these phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, it should be understood that implementing such a feature, structure, or characteristic in conjunction with other embodiments is within the knowledge of those skilled in the art, whether explicitly described or not.

[0050] For ease of description, spatial relative terms are used here to describe the relationship between one element or feature and another, as shown in the figure. In addition to the orientation shown in the figure, spatial relative terms are intended to cover different orientations of the device during use or operation. The device may be oriented in other ways (rotated 90 degrees or other directions), and the spatial relative descriptors used herein can be interpreted accordingly.

[0051] The terms “approximately,” “substantially,” or “approximately” as used herein refer to the value of a given quantity, which may vary based on a particular technique. Depending on the specific implementation, the terms “approximately,” “substantially,” or “approximately” may refer to the value of a given quantity that varies, for example, within 1-15% of that value (e.g., 1%, 2%, 5%, 10%, or 15% of that value).

[0052] Embodiments of this disclosure can be implemented in hardware, firmware, software, or any combination thereof. Embodiments of this disclosure can also be implemented as instructions stored on a tangible machine-readable medium, which can be read and executed by one or more processors. A machine-readable medium can include any mechanism for storing or transmitting information in a machine-readable form (e.g., a computing device). For example, a machine-readable medium can include read-only memory (ROM); random access memory (RAM); disk storage media; optical storage media; flash memory devices; electrical, optical, acoustic, or other forms of propagation signals (e.g., carrier waves, infrared signals, digital signals) and other signals. Furthermore, firmware, software, routines, and / or instructions may be described herein as performing certain actions. However, it should be understood that such descriptions are merely for convenience, and such actions are actually generated by a computing device, processor, controller, or other device executing the firmware, software, routines, instructions, etc.

[0053] Before describing such embodiments in more detail, it is useful to present example environments in which embodiments of this disclosure may be implemented.

[0054] See Figure 1AThe lithography system 100 includes a light source 105 that provides a light beam 160 to a lithography exposure apparatus 169, which processes a wafer 170 received by a wafer holder or stage 171. The light beam 160 is a pulsed beam, comprising time-separated light pulses. The lithography exposure apparatus 169 includes a projection optics system 175 and a measurement system 172, through which the light beam 160 passes before reaching the wafer 170. The measurement system 172 may include, for example, a camera or other device capable of capturing images of the wafer 170 and / or the light beam 160 located at the wafer 170, or an optical detector capable of capturing data describing the characteristics of the light beam 160, such as the intensity of the light beam 160 at the wafer 170 in the xy-plane. The lithography exposure apparatus 169 may be a liquid immersion system or a dry system. The lithography system 100 may also include a control system 150 for controlling the light source 105 and / or the lithography exposure apparatus 169. As shown in the figure, in some embodiments, the control system may receive a measurement signal 151 from the measurement system 172, which indicates the measurement result performed by the measurement system 172. The control system may use signal 150 to generate a control signal 152 to control the light source 105 and / or the photolithography exposure apparatus 169.

[0055] For example, microelectronic features are formed on wafer 170 by exposing a radiation-sensitive photoresist material layer on wafer 170 with a light beam 160. See also Figure 1B The projection optical system 175 includes a slit 176, a mask 174, and a projection objective including a lens 177. A light beam 160 enters the optical system 175 and is projected onto the slit 176, and at least a portion of the light beam 160 passes through the slit 176. Figure 1A and 1B In the example, slit 176 is rectangular, causing the cross-section of beam 160 to have an elongated rectangular shape. A pattern is formed on mask 174. This pattern determines which portions of the shaped beam are transmitted through mask 174 and which portions are blocked by mask 174. The design of the pattern is determined by the specific microelectronic circuitry design that will be formed on wafer 170.

[0056] The shaping beam interacts with mask 174. A portion of the shaping beam transmitted through mask 174 passes through (and may be focused by) projection lens 177 and exposes wafer 170. The portion of the shaping beam transmitted through mask 174 forms a spatial image in the xy plane within wafer 170. This spatial image is an intensity pattern formed by the light reaching wafer 170 after interacting with mask 174.

[0057] System 100 is capable of forming multiple spatial images during a single exposure pass, each spatial image located at a different spatial position along the z-axis in wafer 170. See also Figure 1CIt shows a cross-sectional view of the wafer 170 in the yz plane, where the projection optics system 175 forms two spatial images 173a and 173b at different planes along the z-axis during a single exposure pass. As described in more detail below, one of the spatial images 173a and 173b is formed by light having a first dominant wavelength, while the other of the spatial images 173a and 173b is formed by light having a second dominant wavelength different from the first dominant wavelength.

[0058] The position of the spatial image along the z-axis depends on the characteristics of the optical system 175 (including the projection lens 177 and the mask 174) and the wavelength of the beam 160. The focusing position of the lens 177 depends on the wavelength of the light incident on the lens 177. Therefore, the position of the spatial image can be controlled by changing or otherwise controlling the wavelength of the beam 160. By providing pulses with different primary light wavelengths during a single exposure pass, multiple (two or more) spatial images located at different positions along the z-axis can be formed in a single exposure pass without physically moving the optical system 175 (or any component of the optical system 175) and the wafer 170 relative to each other along the z-axis.

[0059] In the example of Figure 1B, light passing through mask 174 is focused onto a focal plane by projection lens 177. The focal plane of projection lens 177 is located between projection lens 177 and wafer stage 171, and its position along the z-axis depends on the characteristics of optical system 175 and the wavelength of light beam 160. Spatial images 173a and 173b are formed by light of different wavelengths, and therefore are located at different locations (depths) within wafer 170. Spatial images 173a and 173b are spaced apart from each other along the z-axis by a spacing distance 179. The spacing distance 179 depends on the difference between the wavelengths of the light forming spatial image 173a and the wavelengths of the light forming spatial image 173b.

[0060] The spacing 179 arises from the ability to control the dominant wavelength of the pulse passing through the mask 174 during the exposure cycle. Furthermore, spatial images 173a and 173b coexist at wafer 170 during the same exposure cycle. In other words, system 100 does not require spatial image 173a to be formed in the first exposure cycle, while spatial image 173b is formed in a second subsequent exposure cycle.

[0061] Light in the first spatial image 173a interacts with the wafer at depth 178a, and light in the second spatial image 173b interacts with the wafer at depth 178b. These interactions may form electronic features or other physical properties on the wafer 170, such as openings or holes. Since spatial images 173a and 173b are formed at locations displaced along the z-axis, forming spatial images 173a and 173b can be performed as part of a process for fabricating three-dimensional features on the wafer 170. For example, spatial image 173a can be used to form a peripheral region, while spatial image 173b can be used to form channels, trenches, or recesses located at different locations along the z-axis. Therefore, the techniques discussed herein can be used to form three-dimensional semiconductor components, such as three-dimensional NAND flash memory components.

[0062] Before discussing the additional details related to forming multiple spatial images in a single exposure pass, regarding Figures 2A-2C , Figures 3A-3C and Figure 4 An example implementation of the light source 105 and the lithography system 100 is described.

[0063] See Figure 2A A block diagram of the photolithography system 200 is shown. System 200 is a derivative of system 100. Figure 1A An example of an implementation of the lithography system 200. For example, in the lithography system 200, a light source 205 is used as a light source 105 ( Figure 1A A light source 205 generates a pulsed beam 260, which is provided to the photolithography exposure apparatus 169. The light source 205 may be, for example, an excimer light source, which outputs the pulsed beam 260. When the pulsed beam 260 enters the photolithography exposure apparatus 169, it is guided through the projection optics system 175 and projected onto the wafer 170. In this way, one or more microelectronic features are patterned onto the photoresist on the wafer 170, followed by development and cleaning, and then subsequent process steps; this process is repeated. The photolithography system 200 also includes a control system 250, which... Figure 2A In the example, components connected to the light source 205 and the photolithography exposure apparatus 169 are used to control various operations of the control system 200. The control system 250 is... Figure 1A An example of one implementation of the control system 150.

[0064] like Figure 2AAs shown, light source 205 is a two-stage laser system comprising a master oscillator (MO) 212 that supplies a seed beam 224 to a power amplifier (PA) 230. MO 212 and PA 230 can be considered as a subsystem of light source 205 or as part of a system comprising light source 205. Power amplifier 230 receives the seed beam 224 from master oscillator 212 and amplifies it to generate a beam 260 for use in photolithography exposure apparatus 169. For example, master oscillator 212 can emit pulsed seed beams, each with a seed pulse energy of approximately 1 millijoules (mJ), and these seed pulses can be amplified by power amplifier 230 to approximately 10 to 15 mJ.

[0065] The master oscillator 212 includes: a discharge chamber 214 having two elongated electrodes 217; a gain medium 219, which is a gas mixture; and a fan (not shown) for circulating the gas between the electrodes 217. The resonator is formed by an LNM 216 located on one side of the discharge chamber 214 and an output coupler 218 located on the opposite side of the discharge chamber 214. As described above, the LNM 216 may include diffractive optics, such as a grating, which finely tunes and shifts the spectral output of the discharge chamber 214.

[0066] Figure 2B and Figure 2C Additional details about LNM 216 are provided. Figure 2B This is a block diagram illustrating one example of an implementation of the spectral feature selection module 258. The spectral feature selection module 258 is coupled to light propagating in the light source 205. In some implementations (such as...) Figure 2B In the embodiment shown, the spectral feature selection module 258 receives light from the chamber 214 of the master oscillator 212 to enable fine tuning of spectral features such as wavelength and bandwidth within the master oscillator 212.

[0067] The spectral feature selection module 258 may include a control module, such as a spectral feature control module 254, which includes electronics in any combination of firmware and software. The control module 254 is connected to one or more actuation systems, such as spectral feature actuation systems 255_1 to 255_n. Each actuation system 255_1 to 255_n may include one or more actuators connected to corresponding optical features 256_1 to 256_n of the optical system 257.

[0068] Optical features 256_1 to 256_n are configured to adjust the spectral characteristics of the beam 260. Control module 254 receives control signals from control system 250, which include specific commands for operating or controlling one or more actuation systems 255_1 to 255_n. Actuation systems 255_1 to 255_n can be selected and designed to work together, i.e., to cooperate; or actuation systems 255_1 to 255_n can be configured to work individually. Furthermore, each actuation system 255_1 to 255_n can be optimized to respond to specific types of disturbances.

[0069] Each actuator in the actuation systems 255_1 to 255_n can be an EAE for moving or controlling a corresponding optical feature 256_1 to 256_n of the optical system 257. The actuator receives energy from the control module 254 and converts that energy into motion of the optical features 256_1 to 256_n of the optical system 257.

[0070] Each optical feature 256_1 to 256_n is optically coupled to a beam 260 generated by the light source 205. The optical system 257 can be implemented as follows: Figure 2C The LNM 216c is shown. The optical features 256_1 to 256_n of the LNM 216c include dispersive optical elements (such as a reflective grating 291) and refractive optical elements (such as prisms 292, 293, 294, and 295). One or more of prisms 292, 293, 294, and 295 may be rotatable. An example of such a line narrowing module can be found in U.S. Patent No. 8,144,739, issued March 27, 2012, entitled “System Method and Apparatus for Selecting and Controlling Light Source Bandwidth” (hereinafter referred to as “Patent 739”). In Patent 739, an LNM is described that includes a beam expander (including one or more prisms 292, 293, 294, and 295) and dispersive elements (such as grating 291).

[0071] All patent applications, patents, and print publications cited herein are incorporated herein in their entirety, unless otherwise defined, subject matter disclaimer, or disclaimer, and unless the incorporated material is inconsistent with what is expressly disclosed herein, in which case the language of this disclosure shall prevail.

[0072] The corresponding drive systems for the optical features (such as one or more of prisms 292, 293, 294, and 295) are respectively provided by Figure 2CThe EAEs in the diagram are 292a, 293a, 294a, and 295a. Additionally, a reflector may be present, and rotating the reflector can change the angle of incidence of the beam on the grating 291, thereby altering the dominant wavelength of the emitted light. Each prism has an EAE that moves the prism under the control of a voltage command signal. Therefore, typically, the LNM 216c includes one or more optical elements that are rotated to change the dominant wavelength of the light emitted from the module. These EAEs must be able to move the optical elements rapidly between two positions (typically two angular positions); this process is called jitter.

[0073] Back Figure 2A The master oscillator 212 also includes a line center analysis module 220 for receiving the output beam from the output coupler 218, and a beam coupling optics system 222 for modifying the size or shape of the output beam as needed to form a seed beam 224. The line center analysis module 220 is a measurement system used to measure or monitor the wavelength of the seed beam 224. The line center analysis module 220 can be placed at other locations within the light source 205, or at the output end of the light source 205.

[0074] The power amplifier 230 includes a beam-coupled optics system 232 that receives a seed beam 224 from the master oscillator 212 and directs the seed beam 224 to the discharge chamber 240, and then directs the beam to a beam-directing optics element 248. The beam-directing optics element 248 modifies or alters the direction of the seed beam 224 so that it returns to the discharge chamber 240. The discharge chamber 240 includes a pair of elongated electrodes 241, a gain medium as a gas mixture, and a fan (not shown) for circulating the gas mixture between the pair of electrodes 241.

[0075] The output beam 260 is guided through a bandwidth analysis module 262, where various parameters of the beam 260 (such as bandwidth or wavelength) can be measured. The output beam 260 can also be guided through a beam preparation system 263. The beam preparation system 263 may include, for example, a pulse broadener, in which each pulse of the output beam 260 is temporally broadened, for example in an optical delay unit, to adjust the performance characteristics of the beam projected onto the photolithography exposure apparatus 169. The beam preparation system 263 may also include other components capable of acting on the beam 260, such as, for example, reflective and / or refractive optical elements (such as, for example, lenses and mirrors), filters, and optical apertures (including automatic shutters).

[0076] The lithography system 200 also includes a control system 250. Figure 2AIn the illustrated embodiment, the control system 250 is connected to various components of the light source 205. For example, the control system 250 can control when the light source 205 emits light pulses or pulse trains comprising one or more light pulses by sending one or more trigger signals to the light source 205. The control system 250 is also connected to the photolithography exposure apparatus 169. Therefore, the control system 250 can also control various aspects of the photolithography exposure apparatus 169. For example, the control system 250 can control the exposure of the wafer 170, and thus can be used to control how features are printed on the wafer 170. In some embodiments, the control system 250 can control the slit 176 at ( Figure 1B The scanning of the wafer 170 is controlled by motion in the xy plane. Furthermore, the control system 250 can exchange data with the measurement system 172 and / or the optical system 175.

[0077] The photolithography exposure apparatus 169 may also include, for example, temperature control devices (such as air conditioning and / or heating devices) and / or power supplies for various electronic components. The control system 250 may also control these components. In some embodiments, the control system 250 is implemented as including more than one sub-control system, wherein at least one sub-control system (photolithography controller) is specifically designed to control aspects of the photolithography exposure apparatus 169. In these embodiments, the control system 250 may be used to control aspects of the photolithography exposure apparatus 169, either in place of or as a supplement to the use of a photolithography controller.

[0078] The control system 250 includes an electronic processor 251, an electronic storage device 252, and an I / O interface 253. The electronic processor 251 includes one or more processors suitable for executing computer programs, such as general-purpose or special-purpose microprocessors, and one or more processors of any type of digital computer. Typically, the electronic processor receives instructions and data from read-only memory, random access memory, or both. The electronic processor 251 can be any type of electronic processor.

[0079] Electronic storage device 252 can store various recipes or processing procedures 259 that specify parameters of the beam 260 during use. For example, electronic storage device 252 can store a recipe that indicates the wavelength of each pulse in the beam 260 for a specific exposure pass. This recipe can indicate different wavelengths for different exposure passes. The wavelength control techniques discussed below can be applied pulse-by-pulse. In other words, the wavelength content of each individual pulse in the exposure pass can be controlled to form a spatial image at a desired location along the z-axis.

[0080] Electronic storage device 252 may be volatile memory (such as RAM) or non-volatile memory. In some embodiments, electronic storage device 252 includes both non-volatile and volatile portions or components. Electronic storage device 252 may store data and information for the operation of control system 250, components of control system 250, and / or systems controlled by control system 250. This information may be stored, for example, in a lookup table or database. For example, electronic storage device 252 may store data indicating various characteristic values ​​of beam 260 under different operating conditions and performance scenarios.

[0081] The electronic storage device 252 may also store instructions (possibly as computer programs) that, when executed, enable the processor 251 to communicate with components in the control system 250, the optical system 205, and / or the photolithography exposure apparatus 169.

[0082] I / O interface 253 is any type of electronic interface that allows control system 250 to receive data and signals, and / or provide data and signals to the operator, optical system 205, photolithography exposure apparatus 169, any component or system within optical system 205 and / or photolithography exposure apparatus 169, and / or automated processes operating on other electronic devices. For example, I / O interface 253 may include one or more of a visual display, a keyboard, and a communication interface.

[0083] Beam 260 (and beam 160) are pulsed beams and may comprise one or more pulse trains spaced apart from each other in time. Each pulse train may comprise one or more optical pulses. In some embodiments, a pulse train may comprise hundreds of pulses, for example, 100-400 pulses. Figures 3A-3C An overview of the generation of pulses and pulse trains in light source 205 is provided. Figure 3A The amplitude of the wafer exposure signal 300 was shown to change over time. Figure 3B The amplitude of the gate signal 315 changes over time, and Figure 3C The amplitude of the trigger signal 330 changes over time.

[0084] The control system 250 can be configured to send a wafer exposure signal 300 to the light source 205 to control the light source 205 to generate a beam 260. Figure 3A In the example shown, during the period when the light source 205 generates a light pulse train, the wafer exposure signal 300 has a high value 305 (e.g., logic 1) during the time period 307. Otherwise, when the wafer 170 is not exposed, the wafer exposure signal 300 has a low value 310 (e.g., logic 0).

[0085] See Figure 3BThe control system 250 also controls the duration and frequency of the pulse train by sending a gate signal 315 to the light source 205. The gate signal 315 has a high level 320 (e.g., logic 1) during the pulse train and a low level 325 (e.g., logic 0) during the time interval between consecutive pulse trains. In the illustrated example, the duration for which the gate signal 315 has a high value is also the duration of the pulse train 316. The pulse trains are temporally separated by inter-pulse train time intervals. During the inter-pulse train time intervals, the photolithography exposure apparatus 169 can position the next die on the wafer 170 for exposure.

[0086] See Figure 3C The control system 250 also uses a trigger signal 330 to control the repetition rate of pulses within each pulse train. The trigger signal 330 includes a trigger 340 provided to the light source 205 to cause the light source 205 to generate light pulses. The control system 250 can send the trigger 340 to the light source 205 each time a pulse is to be generated. Therefore, the repetition rate of the pulses generated by the light source 205 (the reciprocal of the time between two consecutive pulses) or other pulse timing can be set by the trigger signal 330.

[0087] As described above, when the gain medium 219 is pumped by applying a voltage to electrode 217, the gain medium 219 emits light. When a voltage is applied to electrode 217 in a pulsed manner, the light from medium 219 is also emitted in a pulsed manner. Therefore, the repetition rate of the pulsed beam 260 is determined by the rate at which the voltage is applied to electrode 217, wherein each application of voltage generates a light pulse. This light pulse propagates through the gain medium 219 and exits from chamber 214 via output coupler 218. Thus, a series of pulses can be generated by periodically repeating the application of voltage to electrode 217. For example, trigger signal 330 can be used to control the voltage applied to electrode 217 and the repetition rate of the pulses, which, for most applications, ranges from approximately 500 Hz to 6000 Hz. In some embodiments, the repetition rate can be greater than 6000 Hz, and for example, it can be 12000 Hz or higher.

[0088] Signals from control system 250 can also be used to control electrodes 217 and 241 within master oscillator 212 and power amplifier 230, respectively, to control the corresponding pulse energies of master oscillator 212 and power amplifier 230, and thus control the energy of beam 260. There may be a delay between the signal provided to electrode 217 and the signal provided to electrode 241. The amount of delay may affect characteristics of beam 260, such as the coherence of the pulsed beam 260.

[0089] The average output power of the pulsed beam 260 can be tens of watts, for example, from about 50W to about 130W. The irradiance (i.e., average power per unit area) of the beam 260 at the output end can range from 60W / cm². 2 Up to 80W / cm 2 .

[0090] See also Figure 4 The wafer 170 is irradiated by a beam 260. The photolithography exposure apparatus 169 includes an optical system 175. Figure 1A and Figure 1B ).exist Figure 4 In the example, optical system 175 ( Figure 4 Other parts (not shown) include an irradiator system 429, which includes an objective lens assembly 432. The objective lens assembly 432 includes a projection lens 177. Figure 1B The irradiator system 429 can transfer an image from mask 174 onto a photoresist on wafer 170. The irradiator system 429 adjusts the angular range of the beam 260 projected onto mask 174. The irradiator system 429 can also homogenize the intensity distribution of the beam 260 in the xy plane on mask 174.

[0091] In some embodiments, an immersion medium may be provided to cover the wafer 170. The immersion medium may be a liquid used for liquid immersion lithography (such as water). In other embodiments where the lithography is a dry system, the immersion medium may be a gas, such as dry nitrogen, dry air, or clean air. In other embodiments, the wafer 170 may be exposed to a pressure-controlled environment (such as a vacuum or partial vacuum).

[0092] Multiple pulses of beam 260, number N, irradiate the same area of ​​wafer 170. N can be any integer greater than 1. Multiple pulses of beam 110, number N, irradiate the same area, which may be referred to as the exposure window or exposure path 400. The size of window 400 can be controlled by slit 176. For example, slit 176 may include multiple movable blades, such that the blades form an aperture that is open in one configuration and closed in another. The size of window 400 can also be controlled by arranging the blades of slit 176 to form an aperture of a specific size.

[0093] The N pulses also determine the irradiation dose used for exposure formation. Irradiation dose is the amount of light energy delivered to wafer 170 during the exposure cycle. Therefore, the number N and the characteristics of the N pulses (such as the light energy in each pulse) determine the irradiation dose. Furthermore, as described in more detail below, the N pulses can also be used to determine the irradiation dose for each spatial image 173a, 173b (…). Figure 1CThe amount of light in the image. In particular, the formulation may specify a certain number of N pulses having a first dominant wavelength that forms spatial image 173a, and a certain number of N pulses having a second dominant wavelength that forms spatial image 173b. These two types of pulses will have wavelengths that are different from each other, and may be distributed, for example, pulse by pulse or in some other way (i.e., in the form of alternating groups of pulses).

[0094] Additionally, slit 176 and / or mask 174 can be moved in the scanning direction in the xy plane, such that only a portion of wafer 170 is exposed at a given time or during a specific exposure scan (or exposure stroke). The size of the area on wafer 170 exposed by beam 160 is determined by the distance between blades in the non-scanning direction and the length (distance) of the scan in the scanning direction. In some embodiments, the value of N is in the tens; for example, each point on the wafer can receive light from 10-100 consecutive pulses during the scanning of the slit relative to that point. In other embodiments, the value of N is greater than 100 pulses, for example, from 100 to 500 pulses. The exposure field 479 of wafer 170 is the physical area of ​​wafer 170 exposed in a single scan of the exposure slit or window within the photolithography exposure apparatus 169.

[0095] The wafer stage 171, mask 174, and objective lens assembly 432 are coupled to an associated actuation system to form a scanning apparatus. In the scanning apparatus, one or more of the mask 174, objective lens assembly 432, and wafer 170 can move relative to each other in the xy-plane (via the stage 171). However, apart from occasional relative operative movements between the wafer stage 171, mask 174, and objective lens assembly 432, these elements do not move relative to each other along the z-axis during the exposure journey.

[0096] See you again Figure 2A Typically, wavelength tuning of the seed beam 224, and consequently beam tuning of 260, occurs within the LNM 216. A typical technique for laser linewidth narrowing and tuning involves providing a window at the rear of the laser discharge cavity through which a portion of the laser beam enters the LNM 216. Within the LNM 216, this portion of the beam is expanded by a prism beam expander and guided to a grating that reflects a selected, narrower portion of the laser's broader spectrum back into the discharge cavity, where it is combined with... Figure 2C Amplification is performed in the manner described in LNM 216c. The laser is typically tuned by using one or more EAEs (such as, for example, PZT) to change the angle at which the beam illuminates the grating 291.

[0097] In some embodiments, multiple prisms 292-295 can be used to adjust the final angle of incidence, thereby adjusting the selected wavelength. For example, prism 292 may have a stronger control over the final angle of incidence than prism 293. That is, in some embodiments, controller 250 uses prisms 292 and 293 in a dual-stage configuration, where prism 292 is used for large jumps and to desaturate prism 293, and prism 293 is used for finer changes in the final angle of incidence, saturation occurring when the output of controller 250 exceeds the physical limit of actuator EAE 293a of prism 293. Controlling prisms 292 and 293 is particularly important for MFI operation, which requires not only adjustments around a setpoint but also precise tracking of a sine wave with the Nyquist frequency and precise control of the center point of the sine wave (i.e., the center wavelength).

[0098] As previously mentioned, MFI operation can include a two-color mode. In two-color mode, the wavelength target can alternate between two known setpoints within a pulse train (e.g., per pulse, pulse-by-pulse), and the EAE implemented as PZT can be used to track rapidly changing wavelength targets, i.e., adjust the wavelength towards rapidly changing wavelength targets.

[0099] In some embodiments, a dithering waveform (or sequence) can be used in conjunction with an offset to move the actuator of prism 293. For example, the dithering waveform can be an application of noise for randomized quantization. The offset can be updated at the end of the pulse train (EOB) and / or at set pulse intervals. In some embodiments, the EOB update can move the actuator of prism 293 to bring the estimated center wavelength drift obtained by averaging wavelength measurements over the entire pulse train to zero. In some embodiments, the interval update can be based on an estimation process.

[0100] See Figure 5 The spectrum 601A of the optical pulse 600A is shown. The optical pulse 600A has a non-zero intensity within its wavelength band. This wavelength band can also be referred to as the bandwidth or linewidth of the pulse 600A.

[0101] Figure 5 The data shown is the instantaneous spectrum 601A (or emission spectrum) of pulse 600A. Spectrum 601A contains information about how the light energy or power of the pulse of beam 260 is distributed across different wavelengths (or frequencies). Spectrum 601A is depicted in graphical form, where spectral intensity (not necessarily absolutely calibrated) is plotted according to wavelength. Spectrum 601A can be referred to as the spectral shape or intensity spectrum of the pulse of beam 260. Pulse 600A has a dominant wavelength of 602A, in Figure 5In the example, the wavelength corresponds to the peak intensity. Although the description of the pulses of beam 260 and the spatial image formed by the pulses of beam 260 refers to the dominant wavelength of the pulses, the pulses include wavelengths other than the dominant wavelength, and the pulses have a finite bandwidth, which is characterized by an index. For example, the full width (referred to as FWXM) of spectrum 601A at a portion (X) of the maximum peak intensity of the spectral shape can be used to characterize the beam bandwidth. As another example, the spectral width (referred to as EY) that includes a portion (Y) of the integrated spectral intensity can also be used to characterize the beam bandwidth. Pulse 600A is shown as an example of a pulse that is part of beam 260.

[0102] When a portion of wafer 170 is exposed using a pulse 600A, the light in the pulse forms a spatial image. The position of the spatial image in the z-direction ( Figures 1A-1C The value is determined by the dominant wavelength of 602 Å. The dominant wavelengths of the individual pulses in beam 260 can be different from each other.

[0103] The light source 205 can dither or switch the dominant wavelength between the first and second dominant wavelengths on a pulse-by-pulse, pulse-by-pulse, or even intra-pulse basis. In the pulse-by-pulse case, the dominant wavelength of each pulse is different from the dominant wavelengths of its immediate preceding and immediately following pulses. In these embodiments, assuming that all pulses in the beam 260 have the same intensity, allocating the first and second dominant wavelengths in this way will produce two spatial images with the same intensity at different locations in the z-direction.

[0104] In some implementations, a portion of the pulse (e.g., 33%) has a first dominant wavelength, and the remainder (67% in this example) has a second dominant wavelength. Unless the context otherwise requires, "first" and "second" are used here and elsewhere only as distinguishing labels, not as indicating chronological order. In these implementations, assuming all pulses in beam 260 have the same intensity, two spatial images with different intensities are formed. The spatial image formed by the pulses with the first dominant wavelength has an intensity approximately half that of the spatial image formed by the pulses with the second dominant wavelength. In this way, the dose delivered to a specific location in wafer 170 along the z-axis can be controlled by controlling the portion of N pulses with the first dominant wavelength and the portion of N pulses with the second dominant wavelength.

[0105] The pulse portion of the exposure stroke with a specific dominant wavelength can be specified in recipe file 259 stored in electronic storage device 252 (see recipe file 259). Figure 2A Recipe file 259 specifies the proportions of various dominant wavelengths for each exposure pass. Recipe file 259 can also specify proportions for other exposure passes, allowing different proportions to be used for other exposure passes and adjusting or controlling the spatial image on a field-by-field basis.

[0106] See Figure 6 The image shows the spectrum 601B of pulse 600B. Pulse 600B is another example of a pulse of beam 260. The spectrum 601B of pulse 600B has a different shape than that of spectrum 601A. Specifically, spectrum 601B has two peaks, corresponding to the two dominant wavelengths 602B_1 and 602B_2 of pulse 600B. Pulse 600B is a portion of beam 260. When a portion of wafer 170 is exposed using pulse 600B, the light in the pulse forms two spatial images at different locations along the z-axis on the wafer. The positions of the spatial images are determined by the wavelengths of the dominant wavelengths 602B_1 and 602B_2. Therefore, according to one embodiment, one objective of the control system is to control the dominant wavelengths to be oriented toward their respective target values, i.e., to converge each dominant wavelength to its target value, thereby achieving the target value for the spacing distance.

[0107] Figure 5 and Figure 6 The pulse shown can be formed by any hardware capable of generating such pulses. For example, it can be formed using hardware similar to... Figure 2C The LNM forming pulses (such as pulse 600A) of the LNM 216c are used to generate a pulse sequence. As previously described, the wavelength of the light diffracted by grating 291 depends on the angle of incidence of the light incident on the grating. A mechanism for changing the angle of incidence of the light interacting with grating 291 can be used with this line narrowing module to generate a pulse sequence of N pulses for a single exposure pass, wherein the dominant wavelength of at least one of the N pulses is different from the dominant wavelength of the other pulses. For example, one of prisms 292, 293, 294, and 295 can be rotated to change the angle of incidence of the light incident on grating 291 pulse by pulse. In some embodiments, the line narrowing module includes a mirror located in the path of beam 260 that is movable to change the angle of incidence of the light incident on grating 291. For example, U.S. Patent No. 6,192,064, issued February 20, 2001, "Narrow Band Laser with Fine Wavelength Control," discusses an example of such an embodiment.

[0108] See you again Figure 4During a single exposure pass, a group of light pulses travels through mask 174 toward wafer 170. As described above, N light pulses can be provided to wafer 170 during the exposure pass. These N light pulses can be consecutive light pulses in beam 260. The exposed portion of wafer 170 receives the average of the spectra of each of the N pulses in the exposure pass. Therefore, if a portion of the N pulses has a first dominant wavelength and the remainder of the N pulses has a second dominant wavelength, the average spectrum at wafer 170 will be a spectrum including peaks at the first dominant wavelength and peaks at the second dominant wavelength. Similarly, if all or some of the N pulses have more than one dominant wavelength, these dominant wavelengths may form peaks in the average spectrum.

[0109] Figure 7A An example of the average spectrum 701 at wafer 170 is shown. The average spectrum 701 includes a first dominant wavelength 702_1 and a second dominant wavelength 702_2. Figure 7A In the example, the first dominant wavelength 702_1 and the second dominant wavelength 702_2 are separated by a spectral peak spacing 703. The spectral peak spacing 703 makes the first dominant wavelength 702_1 and the second dominant wavelength 702_2 clear, and the average spectrum 701 includes a spectral region with very low or almost no intensity between wavelengths 702_1 and 702_2.

[0110] To achieve MFI, elements in the optical path sequence that transmit the laser to the location where it is used move back and forth (jitter) between two angular positions, where the light has a first wavelength when the element is in one position and a second wavelength when the element is in the other position. The movement of these elements is controlled by a command voltage applied to the EAE, such as a PZT, stepper motor, valve, pressure-controlled device, electromagnet, solenoid, other types of piezoelectric devices, linear motor, hydraulic actuator, voice coil, and / or any other type of device capable of generating power under the control of a control signal.

[0111] Figure 7B This is a graph showing the inter-pulse wavelength measurements relative to the pulse number for a portion of a pulse train. The top dashed line represents the measured wavelength λ of the odd-numbered pulses. 奇数 This is represented as a positive offset from the center wavelength λ0. The bottom dashed line indicates the measurement wavelength λ of even-numbered pulses. 偶数 This is expressed as a negative offset from the center wavelength λ0. In other words, the wavelength is λ0 of each consecutive pulse (i.e., pulse-by-pulse). 奇数 and λ 偶数 Alternating between the two patterns. Depending on the desired dose at the two depths, other patterns may be used alternatively. The center wavelength is typically the center wavelength of the laser radiation pulse before it is shifted up or down (i.e., redshifted or blueshifted).

[0112] As described above, in a device such as that described during monochromatic operation, one or more optical elements in the LNM are used for coarse wavelength adjustment, while other optical elements in the LNM are used for fine wavelength adjustment. To provide multicolor (e.g., dual-color) operation in such a device, at least some of the optical elements in the LNM used for fine wavelength adjustment during monochromatic operation are instead used to generate two wavelengths.

[0113] As mentioned earlier, such devices also have several limitations. During two-color operation, the oscillating prism requires larger angle jitter to achieve a larger peak spacing. Developing actuators that generate this larger angle jitter is challenging. Such actuators would require significantly higher capacitance and much higher drive power (higher current) for control electronics. Furthermore, sacrificing fine wavelength control to achieve dual-wavelength capability negatively impacts wavelength stability. Additionally, the aforementioned design has limited efficiency.

[0114] According to one aspect of an embodiment, these limitations are avoided by introducing a mirror in the radiation path of the LNM, the mirror being positioned to generate multiple wavelengths. Figure 8 This arrangement is illustrated for the LNM 800. The arrangement includes optical elements, such as prisms 820, 830, 840, and 850 as shown. The arrangement also includes a reflector 860. Figure 8 As shown in the example, mirror 860 can be a plane mirror. In other arrangements, mirror 860 can be a curved mirror, such as a concave or convex mirror. In the arrangement shown, beam 810 enters first prism 820. Light from prism 820 propagates to prism 840, which is used for fine wavelength control for monochromatic and bicolor operation. Light from prism 840 is guided to be projected onto and reflected by mirror 860. Mirror 860 jitters between two angular positions, as indicated by the curved arrow. Mirror 860 is arranged such that when it is in one angular position, LNM 800 generates light with a first wavelength; and when it is in the other angular position, LNM 800 generates light with a second wavelength. In the arrangement shown, a relatively small jitter angle can produce a relatively large peak interval. For example, an angular jitter of 1.5 mRad can produce an interval of 45 pm. Prism 850 can be used for coarse wavelength adjustment and control. Ultimately, the light initially introduced as beam 810 is incident on grating 870, where the incident angle determines at least one spectral characteristic of the radiation emitted from LNM 800, such as wavelength, as described above.

[0115] Each of the optical elements (i.e., prisms 820, 830, 840, and 850 and mirror 860) is coupled to EAEs 825, 835, 845, 855, and 865, respectively, in the depicted arrangement, each EAE being arranged in such a way as... Figure 2B In the arrangement shown and described herein, their respective optical elements rotate under the control of applied control signals. More specifically, EAEs 825, 835, 845, 855, and 865 are controlled by controller 880, which may or may not be part of control system 250, or may be part of other control systems. Controller 880 receives control signal 885, which may be generated based on, for example, the measurement center wavelength of beam 810, the measurement peak interval of alternating pulse wavelengths of beam 810, or other measured values.

[0116] Also Figure 8 As shown in the dashed box, prism 840 and its associated EAE 845 can be considered as a fine wavelength control component 847 for monochromatic and dual-color operation. Similarly, prism 850 and its associated EAE 855 can be considered as a coarse wavelength control component 857, while mirror 860 and its associated EAE 865 can be considered as a wavelength switching component 867 that switches the output wavelength of LNM 800 between two spaced setpoints. Those skilled in the art will understand that the order of the fine and coarse wavelength control components in the optical path can be interchanged for some arrangements and implementations.

[0117] like Figure 8 The arrangement shown allows for a smaller increase in the deflection angle between mirror 860 and prism 850 with a smaller jitter angle. This provides the possibility of increasing the jitter range without requiring additional power. It also reduces the requirements of the EAE 865 coupled to mirror 860, thereby reducing stress and design constraints on the EAE 865. This design also provides the possibility of achieving the same level of fine wavelength control in multifocal mode as in monofocal mode, since the same components are used for fine wavelength control in both modes. This contrasts with conventional arrangements, where the components used for fine wavelength control in monofocal mode are tasked with generating multiple wavelengths in multifocal mode, rather than performing fine wavelength control. Furthermore, Figure 8 The embodiment allows for higher per-pulse laser energy because the design allows for optimized prism orientation to reduce the magnification of the LNM800 on the beam 810.

[0118] Therefore, prism 840 is used for fine wavelength control using EAE actuator 845. A second EAE actuator 865 is coupled to mirror 860 to generate two wavelengths by dithering (oscillating) mirror 860. The positions of mirror 860 and prism 840 can be controlled to obtain desired wavelength and peak spacing stability. Simultaneously, the magnification from LNM 800 can be reduced, and the LNM aperture width can be increased to improve laser efficiency and increase laser power output.

[0119] Figure 9 This is a flowchart illustrating an example of an MFI method according to an embodiment. In step S10, a laser radiation pulse is received. In step S20, a prism is used to refract the laser radiation to achieve fine wavelength control. In other words, a prism is used to slightly change the incident angle of the laser on the diffraction grating, thereby achieving fine control over the wavelength of the radiation. Then, in step S30, a mirror is used to deflect the laser radiation by a first amount. Then, in step S40, a prism is used to refract the laser for coarse wavelength control. Then, in step S50, the laser radiation is directed onto the grating to obtain laser radiation with a first adjusted wavelength; in other words, laser radiation that has been coarsely and finely adjusted to a first color for MFI is obtained.

[0120] In the next step of the method, namely step S60, another radiation pulse is received. In step S70, a prism is used to refract the laser radiation for fine wavelength control. Then, in step S80, a mirror is used to deflect the laser radiation by a second amount. For example, this can be achieved by rotating the mirror between pulses, between a first angular position and a second angular position. Then, in step S90, a prism is used to refract the laser radiation for coarse wavelength control. Then, in step S100, the laser radiation is directed onto a grating to obtain laser radiation with a second adjusted wavelength, i.e., the wavelength of a second color, which has been coarsely and finely adjusted by the prism. The process then returns to step S10 to receive another laser radiation pulse. Before repeating step S30, the mirror is reset to its first angular position.

[0121] like Figure 10 As shown, various embodiments and their components may be implemented using, for example, one or more well-known computer systems, such as the example embodiments, systems, and / or devices shown in the figures or otherwise described. Computer system 1200 may be any well-known computer capable of performing the functions described herein.

[0122] Computer system 1200 includes one or more processors (also called central processing units or CPUs), such as processor 1210. Processor 1210 is connected to communication infrastructure or bus 1220.

[0123] One or more processors 1210 may be graphics processing units (GPUs). In one embodiment, a GPU is a specialized electronic circuit designed to process math-intensive applications. GPUs may have a parallel architecture, enabling them to efficiently process large blocks of data in parallel, such as common math-intensive data in computer graphics applications, images, and videos.

[0124] The computer system 1200 also includes one or more user input / output devices 1230, such as a display, keyboard, pointing device, etc., which communicate with the communication infrastructure 1220 through one or more user input / output interfaces 1240.

[0125] The computer system 1200 also includes a main or primary memory 1250, such as random access memory (RAM). The main memory 1250 may include one or more layers of cache. The main memory 1250 has control logic (i.e., computer software) and / or data stored therein.

[0126] The computer system 1200 may also include one or more auxiliary storage devices or memories 1260. Auxiliary memory 1260 may include, for example, a hard disk drive 1280 and / or a removable storage device or drive 1290. The removable storage drive 1290 may be a floppy disk drive, magnetic tape drive, optical disk drive, optical storage device, magnetic tape backup device, and / or any other storage device / drive.

[0127] Hard disk drive 1280 can interact with removable storage unit 1300. Removable storage unit 1300 includes a computer-usable or readable storage device on which computer software (control logic) and / or data are stored. Removable storage unit 1300 can be a floppy disk, magnetic tape, optical disc, DVD, optical storage disc, and / or any other computer data storage device. Other examples of removable storage unit 1300 may include program cartridges and cartridge interfaces (such as those found in video game devices), removable storage chips (such as EPROM or PROM) and their associated slots, memory sticks and USB ports, memory cards and their associated memory card slots, and / or any other removable storage unit and its associated interface. Hard disk drive 1280 reads and / or writes data from removable storage unit 1300 in a well-known manner.

[0128] Similarly, the removable storage device or drive 1290 can interact with the removable storage unit 1310. The removable storage unit 1310 includes a computer-usable or readable storage device on which computer software (control logic) and / or data are stored. The removable storage unit 1310 can be a floppy disk, magnetic tape, optical disc, DVD, optical storage disc, and / or any other computer data storage device. Other examples of the removable storage unit 1310 may include program cartridges and cartridge interfaces (such as those found in video game devices), removable storage chips (such as EPROM or PROM) and their associated slots, memory sticks and USB ports, memory cards and their associated card slots, and / or any other removable storage unit and its associated interface. The removable storage device or drive 1290 reads and / or writes data from the removable storage unit 1310 in a well-known manner.

[0129] Computer system 1200 may also include a communication or network interface 1320. Communication interface 1320 enables computer system 1200 to communicate and interact with any combination of remote devices, remote networks, remote entities, etc. (individually or collectively referred to as reference numeral 1330). For example, communication interface 1320 may allow computer system 1200 to communicate with remote device 1330 via communication path 1340, which may be wireless and / or wired, and may include any combination of LAN, WAN, Internet, etc. Control logic and / or data may be transmitted to and from computer system 1200 via communication path 1340.

[0130] In one embodiment, a non-transitory tangible device or article of manufacture including a non-transitory tangible computer-usable or readable medium on which control logic (software) is stored is also referred to herein as a computer program product or program storage device. This includes, but is not limited to, computer system 1200, main memory 1250, auxiliary memory 1260, and removable storage units 1300 and 1310, as well as tangible articles embodying any combination thereof. When executed by one or more data processing devices, such as computer system 1200, this control logic causes such data processing devices to operate as described herein.

[0131] Based on the teachings contained in this disclosure, it will be clear to those skilled in the art how to use [other methods] besides [other methods]. Figure 10 It will be apparent that embodiments of this disclosure can be made and used with data processing devices, computer systems, and / or computer architectures other than those shown. In particular, embodiments can be implemented using software, hardware, and / or operating systems other than those described herein.

[0132] While the above may have specifically referenced examples used in an optical lithography environment, it should be understood that the examples can be used in other applications, such as imprint lithography, and are not limited to optical lithography, where the environment permits.

[0133] It should be understood that the wording or terminology herein is for descriptive purposes and not for limitation, and therefore the terminology or terminology in this specification shall be interpreted by those skilled in the art based on the teachings herein.

[0134] It should be understood that the specific embodiments section, rather than the summary and abstract section, is intended to be used to interpret the claims. The summary and abstract section may set forth one or more, but not all, exemplary embodiments contemplated by the inventors, and is therefore not intended to limit the embodiments and the appended claims in any way.

[0135] The embodiments have been described above using functional building blocks to illustrate the implementation of specific functions and their relationships. For ease of description, the boundaries of these functional building blocks are arbitrarily defined here. Alternative boundaries can be defined as long as the specified functions and their relationships are properly performed.

[0136] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments that others can readily modify and / or adapt these specific embodiments to various applications based on this disclosure and with knowledge of the art, without departing from the general concept of the embodiments, without excessive experimentation. Therefore, based on the teachings and guidance given herein, such adaptations and modifications are intended to fall within the meaning and scope of equivalents of the disclosed embodiments.

[0137] Additionally, all or a portion of any aspect and / or embodiment may be used in conjunction with all or a portion of any other aspect and / or embodiment, unless otherwise stated. Features, materials, characteristics, or groups described in connection with a particular aspect, embodiment, or example should be understood to be applicable to any other aspect, embodiment, or example described in this section or elsewhere in this specification, unless incompatible with it. All features disclosed in this specification (including any appended claims, abstract, and drawings), and / or all steps of any method or process so disclosed, may be combined in any combination, except for combinations in which at least some of such features and / or steps are mutually exclusive.

[0138] Furthermore, some features described in this disclosure in the context of standalone implementations may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented individually in multiple implementations or in any suitable sub-combination. Moreover, although features may be described above as functioning in certain combinations, in some cases, one or more features from a claimed combination may be removed from that combination, and that combination may be claimed as a sub-combination or a variation of a sub-combination.

[0139] Furthermore, while operations may be depicted in the accompanying drawings or described in the specification in a specific order, these operations do not need to be performed in the specific order or sequence shown, or all operations need not be performed to achieve the desired result. Other operations not depicted or described may be incorporated into the example methods and processes. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the stated operations. Additionally, in other embodiments, operations may be rearranged or reordered. Those skilled in the art will understand that in some embodiments, the actual steps taken in the illustrated and / or disclosed processes may differ from those shown in the accompanying drawings. According to embodiments, some of the steps described above may be omitted, and other steps may be added.

[0140] Furthermore, the features and attributes of the specific embodiments disclosed above can be combined in different ways to form additional embodiments, all of which fall within the scope of this disclosure. Moreover, the separation of various system components in the above embodiments should not be construed as requiring such separation in all embodiments, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products.

[0141] For the purposes of this disclosure, certain aspects, advantages, and novel features have been described herein. It is not necessarily possible to achieve all of these advantages according to any particular embodiment. Therefore, for example, those skilled in the art will recognize that this disclosure may be practiced or performed in a manner that achieves one or a set of advantages taught herein, without necessarily achieving other advantages taught or suggested herein.

[0142] Conditional language such as “can,” “may,” “can,” or “can”, unless specifically stated otherwise or understood otherwise in the context in which they are used, is generally intended to convey that certain embodiments include certain features, elements, and / or steps that are not included in other embodiments. Therefore, such conditional language is not generally intended to imply that one or more embodiments require features, elements, and / or steps in any way, or that one or more embodiments must include logic for determining whether such features, elements, and / or steps are included in any particular embodiment or will be performed, with or without user input or prompting.

[0143] Connective expressions such as "at least one of X, Y, and Z" should be understood in the context of their common usage, unless otherwise expressly stated, meaning that an item, term, etc., can be any of X, Y, or Z. Therefore, such connective expressions generally do not imply that a particular embodiment requires the presence of at least one of X, at least one of Y, and at least one of Z.

[0144] The implementation method may be further described using the following terms: 1. An apparatus comprising: The first wavelength control component is arranged to receive and refract laser radiation; A wavelength switching component is arranged to receive the laser radiation refracted by the first wavelength control component. The wavelength switching component has a first state and a second state. In the first state, the wavelength switching component deflects the laser radiation by a first amount. In the second state, the wavelength switching component deflects the laser radiation by a second amount different from the first amount. A second wavelength control component is arranged to receive and refract laser radiation deflected by the wavelength switching component. The laser radiation refracted by the second wavelength control component is guided to a diffraction grating, wherein the wavelength of the laser radiation diffracted by the diffraction grating depends on the incident angle of the laser radiation on the diffraction grating. 2. The apparatus according to Clause 1, wherein the first wavelength control component is a fine wavelength control component and the second wavelength control component is a coarse wavelength control component. 3. The apparatus according to Clause 1, wherein the first wavelength control component is a coarse wavelength control component and the second wavelength control component is a fine wavelength control component. 4. The apparatus according to Clause 1, wherein the first wavelength control component includes at least one prism. 5. The apparatus according to Clause 1, wherein the second wavelength control component comprises at least one prism. 6. The apparatus according to Clause 1, wherein the wavelength switching component includes a reflector. 7. The apparatus according to Clause 6, wherein the reflector comprises a plane reflector. 8. The apparatus according to Clause 6, wherein the first state of the wavelength switching component corresponds to a first angular position of the reflector, and the second state of the wavelength switching component corresponds to a second angular position of the reflector, the second angular position being different from the first angular position. 9. The apparatus according to Clause 8 further includes an actuator mechanically coupled to the mirror and configured to rotate the mirror between the first angular position and the second angular position in response to a control signal. 10. The apparatus according to Clause 9 further includes a controller adapted to generate the control signal. 11. The apparatus according to Clause 1, wherein the laser radiation is emitted in the form of one or more pulse trains, each pulse train consisting of multiple pulses, and wherein in the first state, the wavelength switching component causes some of the pulses to take a first value of dominant wavelength, and in the second state, causes other pulses in the pulses to take a second value, the second value differing from the first value by a target dominant wavelength interval. 12. The apparatus according to Clause 11, wherein the wavelength switching component includes a mirror, and wherein the first state of the wavelength switching component corresponds to a first angular position of the mirror, and the second state of the wavelength switching component corresponds to a second angular position of the mirror, the second angular position being different from the first angular position. 13. The apparatus of claim 12, wherein the wavelength switching component further comprises an actuator mechanically coupled to the mirror and configured to rotate the mirror between the first angular position and the second angular position in response to a control signal. 14. The apparatus according to Clause 13 further includes a controller adapted to generate the control signal. 15. The apparatus according to Clause 14, wherein the controller is configured to cause the wavelength switching component to alternate the dominant wavelength of the pulse between the first value and the second value pulse by pulse. 16. A method comprising: A first wavelength control operation is performed on the pulse of laser radiation by refracting it using at least one first wavelength control prism to generate a refracted pulse of laser radiation. A mirror is used to deflect the pulse of the refracted laser radiation to generate a pulse of deflected laser radiation. A second wavelength control operation is performed on the deflected laser radiation pulses by using at least one prism to refract the deflected laser radiation pulses, thereby generating additionally refracted laser radiation pulses; and The pulses of the additionally refracted laser radiation are diffracted using a diffraction grating to generate pulses of diffracted laser radiation, wherein the wavelength of the pulses of the diffracted laser radiation depends on the incident angle of the pulses of the additionally refracted laser radiation on the diffraction grating. 17. The method according to Clause 16, wherein the first wavelength control operation is a fine wavelength control operation and the second wavelength control operation is a coarse wavelength control operation. 18. The method according to Clause 16, wherein the first wavelength control operation is a coarse wavelength control operation and the second wavelength control operation is a fine wavelength control operation. 19. The method according to Clause 16, wherein using a reflector to deflect the pulse of the refracted laser radiation to generate a deflected pulse of laser radiation includes projecting the pulse of the refracted laser radiation onto the reflector and controlling the reflector to be in one of a first angular position of the reflector or a second angular position different from the first angular position. 20. The method according to Clause 19, wherein controlling the reflector to be in one of a first angular position of the reflector or a second angular position different from the first angular position, further comprises controlling an actuator mechanically coupled to the reflector, and the actuator being configured to rotate the reflector between the first angular position and the second angular position in response to a control signal. 21. The method according to Clause 20 further includes generating the control signal. 22. A method for generating laser output at a first wavelength or a second wavelength, the method comprising: Laser radiation is generated at a wavelength with a reference wavelength value; The reflector actuator is controlled to adjust the reflector angle of the reflector so that the wavelength value of the laser radiation is shifted, thereby jittering between a first wavelength value and a second wavelength value. 23. The method according to Clause 22 further includes controlling a prism actuator to adjust the prism angle of the first prism to adjust the wavelength of the laser radiation. 24. The method according to Clause 23, wherein the reflector is located in an optical path between the first prism and the second prism, the method further comprising controlling a second prism actuator to adjust a second prism angle of the second prism to coarser adjust the wavelength of the laser radiation compared to the adjustment of the first prism. 25. An apparatus comprising: A diffraction grating in the optical path of a laser beam; A first prism in the optical path of the laser beam, the first prism being movable to adjust the incident angle of the laser beam on the diffraction grating; A second prism in the optical path of the laser beam, the second prism being movable to adjust the incident angle of the laser beam on the diffraction grating; A reflector is inserted in the optical path of the laser beam between the first prism and the second prism, and is rotatable between a first position and a second position, the first position selecting a first incident angle of the laser beam on the diffraction grating, and the second position selecting a second incident angle of the laser beam on the diffraction grating. 26. The apparatus according to Clause 25, wherein the first prism is movable to finely adjust the incident angle of the laser beam on the diffraction grating, and the second prism is movable to coarsely adjust the incident angle of the laser beam on the diffraction grating. 27. The apparatus according to Clause 25, wherein the first prism is movable to coarsely adjust the incident angle of the laser beam on the diffraction grating, and the second prism is movable to finely adjust the incident angle of the laser beam on the diffraction grating. 28. The apparatus according to Clause 25 further includes a controller configured to move the first prism and the second prism based on feedback from a center wavelength detector, the center wavelength detector detecting the center wavelength of the laser radiation. 29. The apparatus according to Clause 28, wherein the controller is configured to move the first prism and the second prism pulse by pulse. 30. The apparatus according to Clause 25, wherein the first prism and the second prism are beam expanders. 31. A method comprising: The rotational position of the oscillating reflector is used to change the incident angle of the laser radiation pulse on the grating pulse by pulse, thereby changing the wavelength of the laser radiation pulse by pulse between two set points. Control the first prism to perform a first adjustment on the incident angle of the laser radiation on the grating; The second prism is controlled to perform a second adjustment on the incident angle of the laser radiation on the grating. 32. The method according to Clause 31, wherein the first adjustment is a fine adjustment and the second adjustment is a coarse adjustment. 33. The method according to Clause 31, wherein the first adjustment is a coarse adjustment and the second adjustment is a fine adjustment. 34. A non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform operations, said operations including: The pulses of laser radiation are refracted by using at least one first wavelength control prism, and the first wavelength control is applied to the pulses of said laser radiation to generate refracted laser radiation pulses. A mirror is used to deflect the pulse of the refracted laser radiation to generate a pulse of deflected laser radiation. A second wavelength control is performed on the pulses of the deflected laser radiation by using at least one second prism to refract the pulses of the deflected laser radiation, thereby generating pulses of additionally refracted laser radiation; and The pulses of the additionally refracted laser radiation are diffracted using a diffraction grating to generate pulses of diffracted laser radiation, wherein the wavelength of the pulses of the diffracted laser radiation depends on the incident angle of the pulses of the additionally refracted laser radiation on the diffraction grating.

[0145] The above-described embodiments and other embodiments are all within the scope of the following claims.

Claims

1. An apparatus comprising: The first wavelength control component is arranged to receive and refract laser radiation; A wavelength switching component is arranged to receive the laser radiation refracted by the first wavelength control component. The wavelength switching component has a first state and a second state. In the first state, the wavelength switching component deflects the laser radiation by a first amount. In the second state, the wavelength switching component deflects the laser radiation by a second amount different from the first amount. A second wavelength control component is arranged to receive and refract laser radiation deflected by the wavelength switching component. The laser radiation refracted by the second wavelength control component is guided to a diffraction grating, wherein the wavelength of the laser radiation diffracted by the diffraction grating depends on the incident angle of the laser radiation on the diffraction grating.

2. The apparatus of claim 1, wherein the first wavelength control component is a fine wavelength control component, and the second wavelength control component is a coarse wavelength control component.

3. The apparatus of claim 1, wherein the first wavelength control component is a coarse wavelength control component, and the second wavelength control component is a fine wavelength control component.

4. The apparatus of claim 1, wherein the first wavelength control component comprises at least one prism.

5. The apparatus of claim 1, wherein the second wavelength control component comprises at least one prism.

6. The apparatus of claim 1, wherein the wavelength switching component includes a reflector.

7. The apparatus of claim 6, wherein the reflector comprises a plane reflector.

8. The apparatus of claim 6, wherein the first state of the wavelength switching component corresponds to a first angular position of the reflector, and the second state of the wavelength switching component corresponds to a second angular position of the reflector, the second angular position being different from the first angular position.

9. The apparatus of claim 8 further includes an actuator mechanically coupled to the mirror and configured to rotate the mirror between the first angular position and the second angular position in response to a control signal.

10. The apparatus of claim 9, further comprising a controller adapted to generate the control signal.

11. The apparatus of claim 1, wherein the laser radiation is emitted in the form of one or more pulse trains, each pulse train consisting of multiple pulses, and wherein in the first state, the wavelength switching component causes some of the pulses to take a first value of dominant wavelength, and in the second state, causes other pulses in the pulses to take a second value, the second value differing from the first value by a target dominant wavelength interval.

12. The apparatus of claim 11, wherein the wavelength switching component includes a mirror, and wherein the first state of the wavelength switching component corresponds to a first angular position of the mirror, and the second state of the wavelength switching component corresponds to a second angular position of the mirror, the second angular position being different from the first angular position.

13. The apparatus of claim 12, wherein the wavelength switching component further comprises an actuator mechanically coupled to the mirror and configured to rotate the mirror between the first angular position and the second angular position in response to a control signal.

14. The apparatus of claim 13, further comprising a controller adapted to generate the control signal.

15. The apparatus of claim 14, wherein the controller is configured as the wavelength switching component to alternate the dominant wavelength of the pulse between the first value and the second value pulse by pulse.

16. A method comprising: A first wavelength control operation is performed on the pulse of laser radiation by refracting it using at least one first wavelength control prism to generate a refracted pulse of laser radiation. A mirror is used to deflect the pulse of the refracted laser radiation to generate a pulse of deflected laser radiation. A second wavelength control operation is performed on the pulses of the deflected laser radiation by using at least one prism to refract the pulses of the deflected laser radiation, thereby generating pulses of additionally refracted laser radiation. as well as The pulses of the additionally refracted laser radiation are diffracted using a diffraction grating to generate pulses of diffracted laser radiation, wherein the wavelength of the pulses of the diffracted laser radiation depends on the incident angle of the pulses of the additionally refracted laser radiation on the diffraction grating.

17. The method of claim 16, wherein the first wavelength control operation is a fine wavelength control operation, and the second wavelength control operation is a coarse wavelength control operation.

18. The method of claim 16, wherein the first wavelength control operation is a coarse wavelength control operation, and the second wavelength control operation is a fine wavelength control operation.

19. The method of claim 16, wherein using a reflector to deflect the pulse of the refracted laser radiation to generate a pulse of deflected laser radiation, comprising: The pulse of the refracted laser radiation is projected onto the reflector, and the reflector is controlled to be in either a first angular position or a second angular position different from the first angular position.

20. The method of claim 19, wherein controlling the reflector to be in one of a first angular position or a second angular position different from the first angular position, further comprising controlling an actuator mechanically coupled to the reflector, and the actuator being configured to rotate the reflector between the first angular position and the second angular position in response to a control signal.

21. The method of claim 20, further comprising generating the control signal.

22. A method for generating laser output at a first wavelength or a second wavelength, the method comprising: Laser radiation is generated at a wavelength with a reference wavelength value; The reflector actuator is controlled to adjust the reflector angle of the reflector so as to shift the value of the wavelength of the laser radiation, thereby jittering between a first wavelength value and a second wavelength value.

23. The method of claim 22, further comprising controlling a prism actuator to adjust the prism angle of the first prism to adjust the wavelength of the laser radiation.

24. The method of claim 23, wherein the reflector is located in an optical path between the first prism and the second prism, the method further comprising controlling a second prism actuator to adjust a second prism angle of the second prism to coarser adjust the wavelength of the laser radiation compared to the adjustment of the first prism.

25. An apparatus comprising: A diffraction grating in the optical path of a laser radiation beam; A first prism is located in the optical path of the laser beam and is movable to adjust the incident angle of the laser beam on the diffraction grating. The second prism is located in the optical path of the laser beam and is movable to adjust the incident angle of the laser beam on the diffraction grating. A reflector is inserted in the optical path of the laser beam between the first prism and the second prism, and is rotatable between a first position and a second position, the first position selecting a first incident angle of the laser beam on the diffraction grating, and the second position selecting a second incident angle of the laser beam on the diffraction grating.

26. The apparatus of claim 25, wherein the first prism is movable to finely adjust the incident angle of the laser beam on the diffraction grating, and the second prism is movable to coarsely adjust the incident angle of the laser beam on the diffraction grating.

27. The apparatus of claim 25, wherein the first prism is movable to coarsely adjust the incident angle of the laser beam on the diffraction grating, and the second prism is movable to finely adjust the incident angle of the laser beam on the diffraction grating.

28. The apparatus of claim 25, further comprising a controller configured to move the first prism and the second prism based on feedback from a center wavelength detector, the center wavelength detector detecting the center wavelength of the laser radiation.

29. The apparatus of claim 28, wherein the controller is configured to move the first prism and the second prism pulse by pulse.

30. The apparatus of claim 25, wherein the first prism and the second prism are beam expanders.

31. A method comprising: The rotational position of the oscillating reflector is used to change the incident angle of the laser radiation pulse on the grating pulse by pulse, thereby changing the wavelength of the laser radiation pulse by pulse between two set points. Control the first prism to perform a first adjustment on the incident angle of the laser radiation on the grating; The second prism is controlled to perform a second adjustment on the incident angle of the laser radiation on the grating.

32. The method of claim 31, wherein the first adjustment is a fine adjustment and the second adjustment is a coarse adjustment.

33. The method of claim 31, wherein the first adjustment is a coarse adjustment and the second adjustment is a fine adjustment.

34. A non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform operations, the operations including: The pulses of laser radiation are refracted by using at least one first wavelength control prism, and the first wavelength control is applied to the pulses of said laser radiation to generate refracted laser radiation pulses. A mirror is used to deflect the pulse of the refracted laser radiation to generate a pulse of deflected laser radiation. A second wavelength control is performed on the pulse of the deflected laser radiation by using at least one second prism to refract the pulse of the deflected laser radiation to generate a pulse of additionally refracted laser radiation. as well as The pulses of the additionally refracted laser radiation are diffracted using a diffraction grating to generate pulses of diffracted laser radiation, wherein the wavelength of the pulses of the diffracted laser radiation depends on the incident angle of the pulses of the additionally refracted laser radiation on the diffraction grating.

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