Spectrally shaping devices and techniques for optical characterization applications

Abstract

The disclosed implementations describe a system comprising: first optics to receive an input beam of light having a plurality of spectral components of light and to disperse the input beam into a plurality of spectral beams, wherein each of the plurality of spectral beams corresponds to one of the plurality of spectral components and propagates along a spatial path that is different from spatial paths of other spectral beams; and second optics to collect a portion of each of the spectral beams, wherein the portion collected depends on the spatial path of the respective spectral beam, and to form an output beam of light from the portion collected of each of the spectral beams, wherein a spectral distribution of the output beam is different from a spectral distribution of the input beam of light.

Description

Technical Field

[0001] This specification generally relates to the fabrication of integrated circuits and other semiconductor devices in processing chambers. More specifically, this specification relates to spectral shaping techniques and devices for the precise optical characterization of substrates and various other objects used in device fabrication. Background Technology

[0002] The fabrication of microelectronic devices and integrated circuits typically involves performing numerous operations on semiconductor, dielectric, and conductive substrates. Examples of these operations include oxidation, diffusion, ion implantation, thin film deposition, cleaning, etching, photolithography, and more. Materials manufactured in this way can include single crystals, semiconductor films, precision coatings, and many other substances used in electronic device manufacturing and other practical applications. As selected types of atoms are added (e.g., via deposition) to or removed from a substrate (e.g., via etching), efficient and accurate quality control monitoring techniques (and systems) become crucial. Underdeveloped or overdeveloped substrates (e.g., under-etched or over-etched) and substrates that fail to meet required specifications can lead to non-compliance or even device failure. Optical control systems that allow real-time monitoring of various stages of device manufacturing significantly improve product quality. This is particularly important given the ever-increasing demands on the quality of semiconductor devices. Attached Figure Description

[0003] This disclosure will be more fully understood in light of the detailed description given below and the accompanying drawings illustrating various embodiments of this disclosure.

[0004] Figure 1A An exemplary embodiment of a manufacturing machine is illustrated, which supports optical inspection of a substrate using spectral shaping.

[0005] Figure 1B An exemplary implementation is illustrated. Figure 1A The manufacturing machine contains electronic modules that enable optical inspection of substrates using optical forming.

[0006] Figure 2A The illustration schematically depicts a series of transformations used to perform spectral shaping on an input beam to perform precise optical characterization of a target within a device fabrication system, according to some embodiments of the present disclosure.

[0007] Figure 2B The illustration schematically depicts a series of transformations for performing spectral shaping on a light beam reflected from a substrate, according to some embodiments of the present disclosure.

[0008] Figure 2CThe diagram illustrates the input beam intensity (before spectral shaping) and the output beam intensity (after spectral shaping) as a function of wavelength λ ranging from near UV to near IR, according to some embodiments of the present disclosure.

[0009] Figure 2D The illustration shows how a variable-width aperture d(y) can be used to achieve spectral shaping according to some embodiments of this disclosure.

[0010] Figure 3 This is an example diagram of an optical system capable of performing spectral shaping on an input beam for precise optical characterization of a target within a device manufacturing system, according to some embodiments of the present disclosure.

[0011] Figure 4A This is an example diagram of an optical system that employs a mirror and is capable of performing spectral shaping on an input beam for precise optical characterization of a target within a device manufacturing system, according to some embodiments of the present disclosure.

[0012] Figure 4B This is an example diagram of another optical system that employs a mirror and is capable of performing spectral shaping on an input beam for precise optical characterization of targets within a device fabrication system, according to some embodiments of this disclosure.

[0013] Figure 5A This is another example diagram of an optical system employing a diffraction grating and capable of performing spectral shaping on an input beam for precise optical characterization of a target within a device fabrication system, according to some embodiments of the present disclosure.

[0014] Figure 5B This is an example diagram of a simplified optical system employing a diffraction grating and capable of performing spectral shaping on an input beam for precise optical characterization of a target within a device manufacturing system, according to some embodiments of the present disclosure.

[0015] Figure 5C An exemplary embodiment of a spectral shape control aperture formed by a blade array, according to some embodiments of this disclosure, is illustrated.

[0016] Figure 5D Another exemplary embodiment of a spectral shape control aperture formed by a dual-blade array, according to some embodiments of the present disclosure, is schematically illustrated.

[0017] Figure 5E Describing some embodiments based on this disclosure that can be used Figures 5C-5D The device depicted herein is used to obtain some exemplary non-limiting shapes of the SSCA.

[0018] Figures 6A-6CExemplary embodiments of a spectral shaping device according to some embodiments of the present disclosure are shown. The spectral shaping device employs optical elements whose axes are laterally offset relative to each other to facilitate spectral shaping of an input beam for accurate optical characterization of a target within a device manufacturing system.

[0019] Figures 7A-7B An example diagram is shown of a spectral shaping device according to some embodiments of the present disclosure, which uses temporal shaping of an input beam for precise optical characterization of a target within a device manufacturing system.

[0020] Figure 8 This is a flowchart of one possible implementation of a method for performing spectral shaping on an input beam for precise optical characterization of a target within a device fabrication system, based on some embodiments of the present disclosure.

[0021] Figure 9 This is a flowchart of one possible implementation of a method for forming an output beam with a target time-averaged spectral profile for precise optical characterization of a target within a processing chamber, based on some embodiments of the present disclosure.

[0022] Figure 10 A block diagram depicts an example processing system according to some embodiments of the present disclosure, which is capable of supporting real-time detection of particulate contaminants present inside a deposition chamber based on light scattering data. Detailed Implementation

[0023] The embodiments disclosed herein provide spectral shaping for various light beams used in optical characterization of substrates and other objects used in semiconductor device manufacturing. Broadband light sources are generally used because more information can usually be obtained when detecting targets with light having a wide range of spectral components. Typically, the light reaching the photodetector has some spectral components that are significantly underrepresented compared to others. This may occur due to the inhomogeneity of the spectrum emitted by the light source(s) and the different attenuation levels of various portions of the emitted light along the optical path. As a result, the photodetector may be saturated by some portions of the spectrum while receiving too little of the wave belonging to other portions of the spectrum.

[0024] Robotic systems allow for the rapid and efficient transfer of substrates to and from processing chambers, and the automated removal of processed substrates. Robotic transfer / removal systems significantly increase manufacturing yields, but introduce specific quality control challenges. At least some (ideally all) of the processed substrates need to be inspected to meet processing specifications. However, stopping manufacturing processes (e.g., randomly) to test incidentally produced substrates has several drawbacks. As a result, substrates subjected to the same tests are exposed to the testing environment (e.g., the test chamber) for longer periods compared to untested substrates. This introduces inherent inaccuracies into the testing process and, additionally, leads to uneven substrate yields, where untested substrates may have properties different from those tested (e.g., tested substrates may have more contaminants due to prolonged exposure to the post-processing environment). Furthermore, even when performed only occasionally, stopping and restarting manufacturing processes reduces the substrate manufacturing rate.

[0025] As a result, it may be advantageous to perform substrate testing "on the fly" (e.g., using optical inspection methods) while the substrate is being transported from a processing chamber to a transfer chamber or a loading / unloading chamber. The optical inspection device may include: a light source for guiding a beam of light to one or more target locations on the substrate; and a photodetector for detecting light reflected from the substrate over a wide range of wavelengths λ and obtaining reflectivity R(λ) data for various target locations on the substrate. Based on the reflectivity (or elliptically polarized) data, a processing device (e.g., a computer system equipped with a processor and memory) can determine various characteristics of the substrate: film thickness, critical pattern size, substrate uniformity (based on a comparison of reflectivity R(λ) across multiple locations on the substrate), amount of contaminants (based on a comparison of reflectivity R(λ) with a reference reflectivity stored in memory), surface smoothness of the substrate (based on the degree of non-specular diffuse reflection of the detected light), and so on.

[0026] It is possible to obtain reflectance data for portions of the visible spectrum, infrared (IR) spectrum, and ultraviolet (UV) spectrum. Since the time available for optical inspection of substrates is inevitably limited, and having data across a wide range of wavelengths is beneficial for the accuracy of substrate characterization, the use of broadband light sources is advantageous for substrate testing.

[0027] However, parallel processing of multiple spectral components across a wide wavelength range presents numerous challenges. The various spectral components emitted by a light source may have different intensities. For example, the emitted IR component may be much weaker than the visible light component. Designing a light source with the desired spectral output can be a challenging task. The various spectral components may attenuate differently along the optical path of light (which can include the path of light incident on the target surface and the path of light reflected from the target surface). For example, the attenuation of the UV component may be significantly greater than that of the visible light portion of the spectrum. As a result, some parts of the spectrum may be several orders of magnitude stronger than others in terms of the intensity of the spectral components of light delivered to the photodetector. This can lead to oversaturation of the photodetector with overrepresented spectral components. For example, even if the IR and UV portions of the spectrum are often crucial for measuring the scale and properties of certain films, the visible light portion of the delivered light may be much stronger than the corresponding IR and UV portions. Simply increasing the overall intensity of the light source may not effectively solve this problem, as such a remedy would correspondingly increase the overrepresented components and cause further saturation of the photodetector.

[0028] Finally, photodetectors may have different sensitivities to various spectral components of the transmitted light. For example, a photodetector may be less sensitive to the IR portion of the spectrum, so ensuring that the IR portion of the transmitted spectrum has a higher intensity relative to other components may be beneficial. Therefore, in many cases, it may be advantageous to control the spectral shape of the light transmitted to the target surface (or similarly, the light transmitted from the target surface to the photodetector) based on the specifications of the light source and photodetector, while also taking into account the attenuation of various spectral components along their optical paths.

[0029] The embodiments disclosed herein overcome this and other drawbacks of the prior art by providing a method for spatially (or temporally) separating a light beam into multiple spectral beams (e.g., a continuous set of spectral beams) and controlling the intensity of the spectral beams to achieve a desired spectral distribution of the light ultimately reaching the photodetector. Spatial separation can be achieved by guiding the input beam into one or more dispersive optics (e.g., prisms, gratings, dispersive scattering media, etc.). In some embodiments, the beam can be guided through one or more apertures to control the intensity of the spectral beams. Temporal separation can be achieved by guiding the input beam through a broadband dynamic filter having multiple narrowband (color) filters configured to engage with the input beam for a controlled amount of time. In some embodiments, the modified spectral beams (using apertures and / or filters) can be recombine (using one or more optical elements such as lenses, mirrors, prisms, gratings, etc.) into a single output beam with a modified (shaped) spectrum.

[0030] The disclosed embodiments provide devices and techniques for spatially and temporally separating various spectral components of a light beam and selectively reducing the intensity of some of these components to achieve an improved spectral distribution for reflection measurements and / or ellipsometric measurements. The presence of improved spectral components (e.g., IR and UV components) that provide valuable optical characterization data of a target (typically indicating deficiencies) allows for more accurate and reliable characterization of the output of a semiconductor manufacturing system.

[0031] The disclosed embodiments relate to various manufacturing techniques using processing chambers (which may include deposition chambers, etching chambers, etc.), such as chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma-enhanced CVD, plasma-enhanced PVD, sputtering deposition, atomic layer CVD, combustion CVD, catalytic CVD, evaporation deposition, molecular beam epitaxy, etc. The disclosed embodiments can be employed in techniques using vacuum deposition chambers (e.g., ultra-high vacuum CVD or PVD, low-pressure CVD, etc.) and techniques using atmospheric pressure deposition chambers. In this document, “light” refers to electromagnetic radiation of any spectral range (including visible light, far-infrared and near-infrared (IR), far-ultraviolet and near-ultraviolet (UV), etc.). “Light” may further include unpolarized (e.g., natural) light, linearly, circularly, or elliptically polarized light, partially polarized light, focused light, divergent light, collimated light, etc.

[0032] Figure 1A This illustration depicts an exemplary embodiment of a manufacturing machine 100 capable of supporting optical inspection of substrates using spectral shaping. In one embodiment, the manufacturing machine 100 includes a loading station (loading locking chamber) 102, a transfer chamber 104, and one or more processing chambers 106. The processing chambers 106 can be engaged with the transfer chamber 104 via a transfer port (not shown). The number of processing chambers(s) associated with the transfer chamber 104 can vary (for example, ...). Figure 1A The document indicates three processing chambers. The transfer chamber 104 may include a robot 108, a robot blade 110, and an optical inspection tool for accurately optically inspecting the substrate 112. The transfer chamber 104 may be maintained at a pressure (temperature) higher (lower) than atmospheric pressure (temperature). The robot blade 110 may be attached to an extendable arm, which is long enough to move the robot blade 110 into the processing chamber 106 to remove the substrate 116 from the chamber after the substrate processing is complete.

[0033] While the covers of the multiple processing chambers 106 remain closed, the robotic blade 110 can enter the multiple processing chambers 106 via a slit valve port (not shown). The multiple processing chambers 106 can contain the processing gases, plasma, and various particles used in the deposition process. A magnetic field can be present inside the multiple processing chambers 106. The interior of the multiple processing chambers 106 can be maintained at a temperature and pressure different from the exterior temperature and pressure of the multiple processing chambers 106.

[0034] As discussed in detail below with reference to other figures, an optical inspection device with spectral shaping 114 may include (not shown) Figure 1A (In the context of this document) A light source, a photodetector, and various optical devices for shaping one or more beams. In some embodiments, the beam to be shaped is a beam generated by the light source and is spectrally shaped before it is incident on an optical target. In some embodiments, the beam to be shaped is a beam reflected from an optical target and is shaped before it is passed to the photodetector. In some embodiments, the light source may be mounted externally to the inspection device, for example, inside (or outside) the transfer chamber 104, loading station 102, or processing chamber 106. In this document, "optical target" may mean an undeveloped substrate, a fully processed substrate, a partially processed substrate (including substrates currently being processed, for example, using deposition or etching techniques), a reference substrate, processing kit tools (e.g., edge rings, used to determine the degree of wear or misalignment of the edge rings), calibration devices, etc.

[0035] In some embodiments, radiation from substrate 112 may be reflected radiation generated in response to incident light from one or more light sources illuminating substrate 112. If the substrate material is opaque to the specific wavelength used and the thickness of the substrate exceeds the penetration depth of that wavelength, the radiation may be substantially reflected from the surface of the substrate. In other embodiments, such as when the substrate is transparent to the detected specific wavelength or the thickness of the substrate is less than the penetration depth of light, the reflected radiation may originate from the entire cross-section of the substrate. In some embodiments, radiation from the substrate may be radiation transmitted through the substrate. For example, the light source may be located on one side of substrate 112 (e.g., above or below the substrate), while the photodetectors (multiple) may be located on the other side of substrate 112 (below or above the substrate, respectively). In such embodiments, robot blade 110 may cover only a portion of the bottom surface of substrate 112, thereby exposing the remaining portion of the bottom surface to facilitate light transmission through the thickness of substrate 112.

[0036] The computer device 118 can control the operation of the robot 108 and the optical inspection device 114, including processing data acquired by the inspection device 114. The computer device 118 can communicate with the electronic module 150 of the robot 108. In some embodiments, this communication can be performed wirelessly.

[0037] Figure 1B An exemplary embodiment of an electronics module 150 is illustrated, supporting optical measurements of a substrate using optical forming within a manufacturing machine 100. The electronics module 150 may include a microcontroller 152 and a memory buffer 154 coupled to the microcontroller 152. The memory buffer 154 can be used to collect and store optical inspection data before transmitting inspection data to a computer device 118. In some embodiments, wireless communication circuitry may be used to transmit the inspection data. In other embodiments, a wired connection between the electronics module 150 and the computer device 118 may be used to transmit data. In some embodiments, the optical inspection data may be stored (buffered) in the memory buffer 154 before being transmitted to the computer device 118. In other embodiments, measurement data may be transmitted to the computer device 118 during data collection without being stored in the memory buffer 154. In some embodiments, the wireless or wired connection may be persistent. In other embodiments, the wireless or wired connection may be established periodically or after inspection is completed or after some other triggered event (e.g., when the memory buffer 154 is nearly full). Electronic module 150 may further include power element 156 and power-on circuitry 158. In some embodiments, power element 156 may be a battery. In some embodiments, power element 156 may be a capacitor. Power element 156 may be rechargeable from power station 180. For example, a battery or capacitor may be recharged after contact with power station 180 (e.g., via a charging docking station). In some embodiments, a charging station may be connected to power element 156 (e.g., via a wired connection). In some embodiments, the connection between charging station 180 and power element 156 may be wireless. In some embodiments, charging station 180 may include a power transmitter, and power element 156 may include a power receiver. When power element 156 is underpowered, power element 156 may send a beacon signal to locate power station 180, and power station 180 may provide power signals to power element 156 until power element 156 is recharged to the required level.

[0038] Microcontroller 152 may be coupled to optical inspection device 114, which may include light source 164 and photodetector 166. Light source 164 may be a narrowband light source, such as a light-emitting diode, laser, bulb, etc. In some embodiments, light source 164 may be a broadband light source. In some embodiments, light source 164 may include more than one light source, for example, multiple narrowband light sources that produce broadband light (when added together). Light source 164 may include additional optical elements (such as filters, absorbers, polarizers, etc.) to control the spectral distribution and / or polarization of the generated light. Photodetector 164 may include one or more spectrographs, diffraction gratings, mirrors, lenses, photodiodes, and other devices. The photodetector 164, alone or in conjunction with the microcontroller 152 and / or the computer device 118, can determine one or more optical responses of a target. The computer device 118 may include, for example, a central processing unit (CPU), a microcontroller, an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a field-programmable gate array (FPGA), or any other type of processing device. The optical response may include reflectivity R(λ) as a function of wavelength, polarization state (including the ratio of two orthogonal polarizations as a function of wavelength and the phase difference between the two orthogonal polarizations), or any other optical quantity that can be used to characterize the substrate (e.g., polarization dependence of reflectivity, rotation angle of the polarization plane after reflection, luminous intensity, etc.).

[0039] Electronic module 150 may also include an accelerometer 168 to facilitate accurate extension and angular rotation of the robot blade 110. Electronic module 150 may also include a temperature sensor 170 to detect the temperature near substrate 112. Electronic module 150 may further include wireless communication circuitry (i.e., a radio circuit system) for receiving wireless commands from computer device 118 and for transmitting optical inspection data to computer device 118. For example, in one embodiment, the radio circuit system may include a radio frequency (RF) front-end module 160 and an antenna 162 (e.g., a UHF antenna), which may be an internal ceramic antenna. The battery may be a high-temperature resistant type, such as a lithium-ion battery, which can be exposed to a chamber temperature of 450°C for short periods (e.g., ranging from one minute to eight minutes).

[0040] Figure 1BSome of the components shown may be located on or at the fixed portion of robot 108. For example, microcontroller 152, memory buffer 154, and RF front-end 160 may be located in such a location. Other components of electronics module 150 may be located on robot blade 110. For example, accelerometer 168 and temperature sensor 170 may be located in such a location. In some embodiments, some components of electronics module 150 may be located on both the fixed portion of robot 108 and the extendable robot blade 110; for example, power component 156 may be located in such a location. In some embodiments, two separate microcontrollers may be used, with one microcontroller located on the fixed portion and the other on the optical inspection device 114.

[0041] In some embodiments, the wireless connectivity facilitated by the RF front-end 160 and antenna 162 can support a communication link between the microcontroller 152 and the computer device 118. In some embodiments, the microcontroller 152, integrated with the robot 108, may have minimal computational capabilities sufficient to transmit information to the computer device 118, where most of the information processing occurs. In other embodiments, the microcontroller 152 may perform most of the computation, while the computer device 118 may provide computational support for specific, processing-intensive tasks. Data received by the computer device 118 may be data obtained from the transmission chamber 104, the processing chamber 106, data generated by optical inspection devices, data temporarily or permanently stored in the memory buffer 154, etc. Data stored in the memory buffer 154 and / or data transmitted to or from the computer device 118 may be in its raw or processed format.

[0042] In one embodiment, an optical measuring device can direct (using the processing power of the microcontroller 152 and / or computer device 118) one or more light beams generated by a light source 164 to one or more locations on the surface of substrate 112 (in some embodiments, this is done while the substrate is being transported by a robotic blade 110). An optical inspection device 114 can collect reflected light data, and the microcontroller 152 and / or computer device 118 can determine one or more characteristics of substrate 112 based on the reflected light data, such as refractive index, optical attenuation (the imaginary part of the refractive index), film thickness, critical dimensions, etc. The microcontroller 152 (or computer device 118) can then output one or more characteristics representing quantities of substrate 112 (and store them in a memory buffer 154), such as the thickness of the film stack on substrate 112 and the critical dimensions of the pattern, thereby characterizing uniformity, smoothness, absence of contaminants, etc. In some embodiments, the reflected light data can include information about the polarization of the reflected light, and the light incident on the surface of the substrate can be linearly (circularly, elliptically) polarized (e.g., s-polarized or p-polarized light).

[0043] In one embodiment, the computer device 118 of the manufacturing machine 100 may include a blade control module 120, an inspection control module 122 (which controls the operation of the light source and optical sensors), and a substrate quality control module 124, as well as a central processing unit (CPU), software, and memory (e.g., ...). Figure 10 (As shown in the diagram). In some embodiments, some of the functions of the blade control module 120, the inspection control module 122, and the substrate quality control module 124 may be implemented as part of the electronics module 150 via the microcontroller 152 and the memory buffer 154.

[0044] Figure 2A A series of transformations 200, according to some embodiments of this disclosure, for performing spectral shaping on an input beam for precise optical characterization of a target within a device fabrication system are schematically illustrated. For the sake of specificity, Figure 2A (And subsequent figures) mention substrate 250, but it should be understood that any other target can be used instead of substrate 250. Although this disclosure mentions a processing chamber, the embodiments disclosed herein can also be used in any other optical system and method in which spectral shaping can be advantageous.

[0045] In one exemplary embodiment, the light source 202 can generate an input beam 204, which may undergo a series of transformations, such as transformations 210-240, before being output to the substrate 250. As described in more detail with reference to the following figures, by Figure 2AEach transformation indicated by the squares in the diagram can be facilitated by one or more hardware devices, including various optical elements. The input beam 204 can be characterized by specifying the spectral content of the beam (e.g., its intensity distribution I(λ)). In some embodiments, a continuous intensity distribution I(λ) can be used. In some embodiments, a series of center wavelengths λ can be specified for multiple spectral ranges Δλ (e.g., a spectral range with a width Δλ = 100 nm (or 150 nm, 200 nm, or any other wavelength range)). j =λ1,λ2,λ 3,… The intensity is used to determine the discrete intensity distribution I(λ). j In some implementations, Δλ can be equal to the distance between center wavelengths (e.g., Δλ = λ3 – λ2). In some implementations, the ranges can overlap, where Δλ is greater than the distance between adjacent center wavelengths. In some implementations, Δλ can be greater than the distance between center wavelengths (so that the ranges do not overlap). In some implementations, the ranges Δλ can have unequal widths. (For example, the ranges can correspond to equal frequency intervals Δf.) In some implementations, Δλ can be made very small (e.g., 1-10 nm), such that the discretized value distribution I(λ) is followed. j The set of descriptions of the input beam 204 is quasi-continuous. In some embodiments, the range Δλ may correspond to the actual emission range of the various emitters of the light source 164 (e.g., the emission range of the light-emitting diodes of the light source 164). In other embodiments, the range Δλ may be defined solely for characterization purposes, and these ranges may not be associated with any particular physical emitter.

[0046] In some implementations, using one or more dispersive optical elements (prisms, diffraction gratings, waveguide openings, fiber tips, etc.), the input beam 204 can undergo spatial dispersion (transformation 210) to be dispersed to the corresponding center wavelength λ. j A corresponding set of spectral beams, each traveling along a separate optical path. Of course, in reality, there can exist a continuous spatial distribution of light frequencies (wavelengths) such that there are no clear boundaries (in frequency or space) between the spectral beams. "Spectral beam" should be understood as a description used for a continuous distribution of light intensity. For example, let λ... j The spectral components within a radius Δλ centered on the target can propagate along an optical path with a central line and a defined spatial range. This spatial range can be described relative to the lateral coordinate y by the half-width of the total intensity of the j-th spectral beam.

[0047]

[0048] The center line y, obtained by dividing the spatial width of the j-th spectral beam, is...j (x) (for each coordinate x along the direction of spectral beam propagation) can be used for quantitative characterization of spectral beam propagation.

[0049] The resulting set of spectral beams can then undergo spectral shaping (transformation 220). For example, the set of spectral beams can be passed through an aperture with a variable width d(y), allowing a portion of each spectral beam to pass through. Due to the spatial separation of the beams, the portion transmitted through the aperture can be a function of the wavelength λ. In some embodiments, spectral shaping 220 can be performed to reduce the spectral dependence of the total intensity. Figure 2C The diagram shows the input beam intensity (before spectral shaping) and the output beam intensity (after spectral shaping) as a function of wavelength λ ranging from near UV to near IR (in one example, the range is 200-1100 nm). The dashed line indicates the spectral intensity of the input beam 204. As shown by the solid line indicating the spectral intensity of the output beam 242, the intensity distribution becomes significantly more uniform after spectral shaping 220. Figure 2D The illustration shows how a variable-width aperture d(y) can be used to achieve spectral shaping according to some embodiments of this disclosure. More specifically, the width allows most spectral components in the IR and UV ranges to pass through the virtually unobstructed aperture, while components in the visible light range are partially blocked. Figure 2D The aperture shown is intended to illustrate an exemplary implementation. In some implementations, the shape of the aperture may be different. For example, it may produce an output beam 242 with non-uniform spectral intensity (e.g., as shown in the image). Figure 2C The area depicted (in dashed lines) can be advantageous (e.g., to anticipate enhancement losses that may occur in the UV portion of the spectrum during the reflection of the output beam from the optical target and during the subsequent propagation of the beam from the optical target to the photodetector). To achieve such an intensity distribution, the aperture size can be further reduced for the visible spectral component.

[0050] Continue to refer to Figure 2A The output beam 242, shaped by spectral shaping, can be used to illuminate the substrate 250. The beam reflected from the substrate 250 can be directed (e.g., via one or more optical fibers) to the photodetector 260 for spectral analysis. In some embodiments, after spectral shaping, one or more optics can perform beam reconstruction (transformation 240). Specifically, spatially separated spectral beams can be combined (using one or more compensating dispersion elements) into a single beam to reduce the spatial extent of the output beam 242. The reduced spatial extent of the beam can have the advantage of allowing the detection of the same point on the target surface of the substrate 250 using different wavelengths. In some embodiments where increasing the spatial resolution of the optical characterization of the target is not critical, beam reconstruction 240 may be optional (as indicated by the dashed line) and may not be performed.

[0051] According to some implementation methods of this disclosure, Figure 2A The diagram illustrates the transmission of a light beam to the substrate 250, while Figure 2B The diagram schematically illustrates a series of transformations 270 used to perform spectral shaping on a light beam reflected from a substrate. Figure 2B In the embodiment shown, the input beam 204 is a beam reflected from the substrate 250, and the output beam 242 is transmitted to the photodetector 260. Figure 2A Similarly, in some embodiments, beam reconstruction 240 may optionally be performed. Because of the linear nature of reflections from substrate 250 (where different spectral components interact independently with the substrate material), Figure 2A and Figure 2B The implementations described herein can lead to substantially the same results. However, in various specific designs, one or the other arrangement may be preferred.

[0052] Figure 3 This is an example diagram of an optical system 300 capable of performing spectral shaping on an input beam for precise optical characterization of a target within a device fabrication system, according to some embodiments of this disclosure. In some embodiments, the input beam 304 (transmitted via optical fiber or through the atmosphere) can be incident on a dispersive prism 306. The dispersive prism 306 can be made of any transparent material having a refractive index n(λ) that depends on the wavelength λ. In some embodiments, the material can be selected based on a refractive index having an imaginary part (which describes the light absorption within the material) n″(λ), which is small over a certain wavelength range whose relative representation in the spectrum of the output light is to be increased. Each of the spectral beams formed by the dispersive prism 306 can be collimated (as indicated by parallel solid lines for wavelength λ1 and parallel dashed lines for wavelength λ2).

[0053] In some embodiments, after spatially separating the various spectral components, the first focusing lens 308 can change the direction of the various spectral beams so that the spectral beams pass through the spectral shape control aperture (SSCA) 310, such as... Figure 2D The diagram is schematically illustrated. SSCA 310 can reduce the intensity of each input spectral beam to the extent necessary to obtain the desired (e.g., predetermined) output intensity of each of the spectral beams. In some embodiments, after passing through the aperture, the spectral components can pass through collimating lens 312 to form a set of collimated beams (again indicated by parallel solid and dashed lines). A second (compensating) prism 314 can be used to form this set of collimated spectral beams into a single output beam 342.

[0054] In some embodiments, the first focusing lens 308 and the collimating lens 312 may be lenses having the same focal length and positioned at equal distances relative to the SSCA 310. In other embodiments, lenses 308 and 312 may have different focal lengths and be positioned at unequal distances relative to the SSCA 310. In some embodiments, the diverging prism 306 may be the same as (however oriented in the opposite manner) as the compensating prism 314 and positioned at the same distance relative to the SSCA 310.

[0055] In some embodiments, the output beam 342 may (optionally) be guided through the second focusing lens 316 to focus the output beam 342 near the opening of the output fiber 320. The output fiber 320 may then be directed toward an optical target (such as...) Figure 2A (as shown) or light detector (such as) Figure 2B The output beam 342 (shown in the diagram) is transmitted (having a reshaped spectral distribution). In some embodiments where the second focusing lens 316 is absent, the corresponding transmission can be performed in air (or atmosphere).

[0056] In various embodiments, the SSCA 310 can have a spatial range of 5-20 mm (along the y-direction) and an aperture width ranging from 10 μm to 1 mm, although in some embodiments the width may be less than or greater than this range. In some embodiments, for optimal performance, the minimum aperture width can be at least ten times the longest wavelength used for optical characterization of the target to remain sufficiently far beyond the diffraction limit.

[0057] Figure 4A This is an example diagram of an optical system 400, based on some embodiments of the present disclosure, employing a mirror and capable of performing spectral shaping on an input beam for precise optical characterization of a target within a device fabrication system. In the depicted embodiment, an input beam 404, transmitted by an input fiber 402 (e.g., from a light source 164), is collimated by a collimating lens 432 before passing through a dispersive prism 434. A focusing lens 436 then focuses the spatially separated spectral beam at SSCA 410. A portion of the spectral beam passing through SSCA 410 is then directed to a second focusing lens 437. The second focusing lens 437 generates a set of collimated spectral beams, which are output to a compensating prism 438 to combine the different spectral beams into a single collimated beam. A third focusing lens 440 can then focus the resulting output beam 442 onto an optical target (e.g., a substrate 450).

[0058] Figure 4BThis is an example diagram of another optical system 460, which employs a mirror and is capable of performing spectral shaping on an input beam for precise optical characterization of a target within a device manufacturing system, according to some embodiments of this disclosure. The input beam 404 is generated by a light source and the output beam 442 is guided to a substrate 450 (or another target). Figure 4A Compared to the implementation method, in Figure 4B In some embodiments, the input beam 404 is generated after the incident light is reflected by the substrate 450 (or another target), and the output beam 442 is collected by the output fiber 420. In some embodiments, the output fiber 420 may then pass the output beam to the photodetector 166.

[0059] Compared to implementation methods that use lenses (e.g.) Figure 3 As illustrated in the diagram, a mirror-based implementation method is used (e.g.) Figures 4A-4B (As illustrated in the illustration) can have certain advantages. Specifically, reflections from a high-quality mirror can be free of dispersion (unlike refraction through a lens, where there is always at least some chromatic aberration). Therefore, mirror-based implementations can introduce less color distortion during spectral shaping compared to lens-based devices. In some implementations, a combination of lenses and mirrors can be used.

[0060] Figure 5A This is another example diagram of an optical system 500 employing a diffraction grating and capable of performing spectral shaping on an input beam for precise optical characterization of a target within a device fabrication system, according to some embodiments of the present disclosure. In the depicted embodiment, an input beam 504, transmitted by an input fiber 502 (e.g., obtained from a light source 164 or reflected from a target), is collimated by a collimating lens 532 and guided toward a dispersive grating 534. As schematically shown, after diffraction at the dispersive grating 534, the light is separated into a set of collimated spectral components propagating in different directions. A focusing lens 536 focuses the spatially separated spectral components (beam) onto an SSCA 510. A portion of the spectral beam passing through the SSCA 510 is then guided toward a second focusing lens 537. The second focusing lens 537 can generate a set of collimated spectral beams, which are output to a compensation grating 538 to combine the different spectral components into a single collimated beam. The collimating lens 540 can then focus the generated output beam 542 onto the output fiber 520 (to deliver the output beam to the target or photodetector).

[0061] Figure 5B This is another example diagram of a simplified optical system 570, which employs a diffraction grating and is capable of performing spectral shaping on an input beam for precise optical characterization of a target within a device fabrication system, according to some embodiments of this disclosure. Figure 5BIn the embodiment illustrated, beam reconstruction is not performed. Specifically, the input beam 504 is a reflected beam generated by the substrate 550 in response to the incident beam 572 guided to the substrate 550 (e.g., guided by the light source 164). After this set of spectral components is focused by the focusing lens 536 and spectrally shaped by the SSCA 510, the spectral components can be directly output to an optical detection device (e.g., array sensor 560) without beam reconstruction. Such an implementation can be advantageous if the array sensor 560 has a wide spatial sensitivity and can accurately determine the spectral intensity of incident light with an extended spatial range. For example, a color sensor for detecting various spectral components can be located at the point where the corresponding spectral component enters the array sensor 560. Figure 5B In the drawing, the light output by the focusing lens 536 is focused at or near SSCA 510. However, in some embodiments, the light can be focused at or near the opening of the array sensor 560 (or at or near the color sensor). In some embodiments, the array sensor 560 may be a linear array sensor.

[0062] like Figures 5A-5B The implementation method using gratings illustrated herein may have advantages over other methods. Figure 3 and Figures 4A-4B The illustration shows some advantages of the prism-based implementation. In detail, the dispersion grating allows for more precise control over the spatial separation of the various spectral components of light because the directions of the diffraction maxima and minima are determined by the geometry of the diffraction apparatus (e.g., the distance between diffraction gratings 534 and 538, the grating spacing, and the angle of incidence of light), rather than by the material parameters of the prism (e.g., the dispersion of the refractive index).

[0063] In some implementations, depending on the type of source (and the type of input beam produced) and the desired target spectral content of the output beam, a fixed set of pre-formed apertures (e.g., SSCA 410, 510, or 610) can be used with the spectral shaping device. In some implementations, the width and / or length of the apertures used to shape the spectral beam can be adjustable. For example, the aperture can be a device with multiple linear blades (which may be straight or curved), the position of which can be manually controlled (by a human operator) or controlled by a processing device (e.g., computer device 118 and / or microcontroller 152). Depending on the number of blades, repositioning the blades forming the aperture can provide quasi-continuous control over the aperture profile d(y).

[0064] Figure 5CAn exemplary embodiment of a spectral shape control aperture (SSCA) formed by an array of blades, according to some embodiments of this disclosure, is illustrated. As schematically depicted, the SSCA can be formed in a (opaque) masking screen 580 by an array 582 of movable blades. The position of the movable blades 582 can be adjusted via an actuator 584. For example, in Figure 5C In the illustrated embodiment, each individual blade can move horizontally until the target shape (white opening) of SSCA 510 is achieved. In other embodiments, individual blades of the blade array 582 can move in more than one direction, such as both horizontal and vertical, or a certain combination of the above directions. The actuator 584 can be operated according to instructions output by the computer device 118 and / or the microcontroller 152, and the actuator 584 can be communicatively coupled to the computer device and / or the microcontroller.

[0065] Figure 5D Another exemplary embodiment of a spectral shape control aperture formed by a dual-blade array, according to some embodiments of this disclosure, is schematically illustrated. For example... Figure 5D As shown, two blade arrays 582-1 and 582-2 can be used to form an SSCA of arbitrary shape. In some embodiments, blade arrays 582-1 and 582-2 can be operated by independently controlled actuators (not shown) to facilitate the formation of arbitrary asymmetric SSCA shapes. In some embodiments, blade arrays 582-1 and 582-2 can be operated by a single actuator, for example, in such a way that the blades in blade array 582-1 and the blades in blade array 582-2 extend toward each other at the same distance, thereby forming a symmetrical (relative to the centerline) SSCA 510. Figure 5E The present disclosure describes some exemplary non-limiting shapes of SSCAs according to some embodiments thereof, which can be used... Figures 5C-5D The device described herein may be used to obtain (or obtained by other means).

[0066] Figures 6A-6B Exemplary embodiments of a spectral shaping device according to some embodiments of the present disclosure are shown. The spectral shaping device employs optical elements whose axes are laterally offset relative to each other to facilitate spectral shaping of an input beam for accurate optical characterization of a target within a device manufacturing system. Figure 6AAn input optical fiber 602 is depicted, which can transmit an input beam to a dispersive waveguide 660. In some embodiments, the dispersive waveguide 660 may be made of a conductive material. In some embodiments, the dispersive waveguide 660 may be made of a dielectric material. In some embodiments, the dispersive waveguide 660 may be hollow. In some embodiments, the dispersive waveguide 660 may be solid (not hollow). The dispersive waveguide 660 may have a cylindrical, elliptical, rectangular, or polygonal shape. The dispersive waveguide 660 may have a fixed cross-section along the length of the waveguide, or it may have a varying cross-section along the length of the waveguide (e.g., the dispersive waveguide 660 may be a tapered waveguide). The dispersive waveguide 660 may have an opening to disperse light into external space, as schematically indicated by the beam splitter 663. The opening may be any type of waveguide termination, including steep cuts, or a gradual opening characterized by a varying cross-section near the opening (e.g., the cross-section may increase or decrease near the opening). As light exits from the opening and interacts with the walls of the dispersive waveguide 660 near the opening (e.g., diffraction, scattering, reflection, refraction), the beam dispersed from the opening can include multiple spectral components propagating along different spatial directions. For example, as schematically depicted in Figure 6 by the varying intensity of the shadows cast by the dispersed beam 663, components propagating primarily along the axis of the dispersive waveguide 660 can have different (e.g., larger) wavelengths (e.g., λ1 > λ2) than those propagating away from the axis.

[0067] In some implementations, the opening of the dispersive waveguide 660 may be specifically designed to increase the dispersion of light and correspondingly increase the diffusion of the spectral components (spectral beam) constituting the scattering beam 663.

[0068] A portion of each of the spectral beams can be collected by receiving waveguide 664. Receiving waveguide 664 can face dispersive waveguide 660. Receiving waveguide 664 can be positioned such that the axes of receiving waveguide 664 and dispersive waveguide 660 are laterally offset relative to each other. Figure 6A In the embodiments illustrated, a larger portion of the spectral components with shorter wavelengths (which have stronger dispersion) λ2 (e.g., the UV component) is collected compared to the portion of the spectral components with longer wavelengths λ1 (e.g., the visible light range component) collected by the receiving waveguide 664. In various embodiments, the lateral offset can be adjustable depending on the desired spectral shaping. In some embodiments, there may be no lateral offset (so that the axes of the two waveguides 660 and 663 coincide). For example, if it is necessary to increase the relative weight of the IR portion of the spectrum at the expense of the visible and / or UV range, the lateral offset can be reduced or set to zero. The light collected by the receiving waveguide 664 can be transmitted to a target (or photodetector) via optical fiber 620.

[0069] Figure 6B Simplified depiction Figure 6A A spectral shaping device, wherein the tip 661 of the input fiber 602 serves as a dispersive waveguide 660, and the tip 665 of the input fiber 602 serves as a receiving waveguide 664. In some embodiments, the dispersive fiber tip 661 and / or the receiving fiber tip 665 are simple cuts of the corresponding fibers 602 and 620. In some embodiments, the dispersive fiber tip 661 and / or the receiving fiber tip 665 may have a cross-section that varies along the corresponding fibers 602 and 620.

[0070] Figure 6C Another embodiment of the spectral shaping device depicts a dispersive prism 662 instead of a dispersive waveguide 660, and a receiving prism 666 instead of a receiving waveguide 664. The dispersive prism 662 can generate a split-scattered beam, while the lateral offset of the receiving prism 666 can be configured such that the desired portion of the spectral components is captured by the receiving prism 666. For example, this offset can cause most of the UV component λ2 to be captured (and directed towards the output fiber 620), while most of the visible light range λ1 components are not captured.

[0071] Figures 7A-7B Example diagrams are shown of spectral shaping devices according to some embodiments of the present disclosure, which use temporal shaping of an input beam for precise optical characterization of a target within a device fabrication system. In the embodiment schematically depicted in FIG. 7, the shaping of the input beam is performed using a dynamic filtering device 700 comprising a series of color filters 771. Figure 7A In a specific, non-limiting embodiment, color filters 771 are arranged around a ring; the center transmission wavelength of each filter is indicated (200 nm, 400 nm, etc.). The dynamic filtering device 700 can rotate at a certain angular velocity ω, exposing the color filter 771 to the input beam 770 transmitted via the input fiber 702. The j-th color filter can achieve a wavelength range Δλ. j It transmits spectral components within a given range and can reflect (or absorb) other spectral components. The j-th color filter can have a length ΔL. j (Calculated along the circumferential direction), its length can differ from other color filters. This is achieved by controlling the length ΔL of each filter. j The spectral intensity of the filtered beam 772 can be modified in a controlled manner by the angular velocity ω of rotation. The filtered beam 772 can then be transmitted via the output fiber 720 to the substrate or any other optical target (if the input beam 770 is generated by a light source) or to a photodetector (if the input beam 770 is a beam reflected from the substrate or some other optical target).

[0072] As an explanation, if the input beam 770 is within the range Δλ corresponding to the j-th color filter... j The spectral intensity I in (λ j If the spectral intensity I of the output beam 772 is... out (λ j The portion Δt of the total rotation period T will be determined by the total rotation period T. j It was determined that during this period, the j-th color filter was exposed to the input beam 770:

[0073]

[0074] Because of the exposure time Δt j With the length ΔL of the color filter j It is proportional to and related to the angular velocity ω(λ) during the time the j-th color filter is exposed to the input beam. j Inversely proportional to Δt j =ΔL j / (Rω(λ j Therefore, the output intensity is:

[0075]

[0076] In some implementations, the desired output intensity can be independent of wavelength. In one implementation, such uniform output intensity can be achieved using a constant rotational angular frequency but with a variable-length filter.

[0077]

[0078] The length of each color filter is inversely proportional to the intensity of the corresponding spectral component of the input beam. For each input beam 770 that can be used for optical characterization of a target (e.g., generated by a specific light source), a specified dynamic filter device 700 can be configured, wherein the length of each color filter is designed to achieve the desired spectral shape of the output beam 772.

[0079] In some implementations where increased flexibility (e.g., the ability to fine-tune the spectral shape of the output beam 772) may be required, the desired output beam profile can be achieved by setting an appropriate angular velocity for each color filter. For example, if all color filters have the same length, uniform output intensity can be achieved using a rotational angular frequency that varies as each color filter is exposed to the input beam 770 according to the following equation:

[0080]

[0081] This ensures that the rotational angular velocity during the exposure of each color filter is proportional to the intensity of the corresponding spectral component of the input beam.

[0082] In some implementations, the two methods described above can be combined. For example, the color filter can have a predetermined length based on the spectral shape of an average input beam 770 that is expected to be received (e.g., corresponding to the factory specifications of a specific light source), and deviations relative to such an average spectral shape can be compensated for by adjusting the angular velocity. In some implementations, a motor (not shown in FIG. 7) (e.g., an electric motor) can rotate the dynamic filter device 700. The motor can be controlled by a processing device (e.g., a microcontroller 152 and / or a computer device 118). The processing device can access reflectivity (elliptically polarized) data output by the photodetector 166 and calculate the angular velocity value ω(λ) required to achieve the desired spectral distribution (e.g., a uniform distribution) of the output beam 772. j The set of angular velocity values. After calculating the set of angular velocity values, the processing device can make the motor receive signals (e.g., digital signals if the motor is equipped with its own microcontroller, or analog signals) to control the motor's rotational angular velocity based on the calculated set of values.

[0083] In some implementations, the processing device can determine the angular velocity value ω(λ) required to achieve the desired spectral distribution based on reflectivity / ellipsoidal polarization data from the calibration device. j The set of calibration devices can be a reference substrate with known optical properties or some other target device.

[0084] Figure 8 This is a flowchart of one possible embodiment of a method 800 for performing spectral shaping on an input beam for precise optical characterization of a target within a device fabrication system, according to some embodiments of this disclosure. Method 800 can be performed using the systems and components described in Figures 1-6, or any combination thereof. In some embodiments, some or all blocks of method 800 can be executed in response to instructions from computer device 118 or microcontroller 152. Microcontroller 152 may be coupled to one or more memory devices (e.g., memory buffer 154). Similarly, computer device 118 may include one or more memory devices. In some embodiments, method 800 can be performed while a target (e.g., a substrate or calibration device) is being processed in processing chamber 106 or being transported through transfer chamber 104. In some embodiments, method 800 can be performed while a calibration device or reference substrate is located in processing chamber 106.

[0085] Method 800 can be performed using a combination of optical elements (e.g., concave and convex mirrors, diverging and condensing lenses, diffraction gratings, apertures, optical fibers, and other optical elements). For ease of explanation, the operation of method 800 is described below with reference to "first optical device" and "second optical device," but it should be understood that in various embodiments, there is no physical boundary that separates the first optical device and the second optical device. In various embodiments, optical elements and functions belonging to the first optical device may belong to the second optical device, and vice versa.

[0086] Method 800 may involve receiving an input beam of light through a first optics device, the input beam having multiple spectral components of light (operation 810). In some embodiments, the input beam may be generated by a light source. In some embodiments, the input beam may be transmitted from the light source to the first optics device via an optical fiber. In some embodiments, the light source may guide (either in the atmosphere or via an optical fiber) an incident beam toward a substrate (or any other target) located within a processing chamber (or transmission chamber) of a substrate manufacturing machine. In such embodiments, the input beam may be a beam reflected from the substrate and formed by the incident beam.

[0087] At operation 820, method 800 may continue by the following step: a first optical device disperses the input beam into multiple spectral beams. In some embodiments, the first optical device may include a prism, diffraction grating, waveguide, or the tip of an optical fiber to disperse the input beam into multiple spectral beams. In some embodiments, it may be suitable to consider multiple spectral beams including at least three spectral beams. The first spectral beam may refer to spectral components in the visible light wavelength range, the second spectral beam may refer to spectral components in the near-IR range, and the third spectral beam may refer to spectral components in the near-UV range. For example, the first spectral beam may have components with wavelengths between 400 nm and 700 nm; the second spectral beam may have components with wavelengths greater than 700 nm; and the third spectral beam may have components with wavelengths less than 400 nm. In other embodiments, more than three spectral beams may be used to characterize the propagation of light in the spectral shaping device used to perform method 800. In some embodiments, continuous (or quasi-continuous) spectral beams may be used to characterize the propagation of light. Each of the multiple spectral beams may propagate along a spatial path different from the spatial path of each of the other multiple spectral beams.

[0088] At operation 830, method 800 may continue by the following steps: a second optics device collects a portion of each of the plurality of spectral beams output by the first optics device. The collected portion of each spectral beam may depend on the spatial path of the respective spectral beam. In some embodiments, the second optics device may include an aperture having a width that varies along a distance of the aperture, wherein each of the spectral beams passes through the aperture at a location different from the location where each of the other spectral beams passes through the aperture. In some embodiments, the width of the aperture may be adjustable at least at multiple locations along the aperture. In some embodiments, the second optics device may include a first focusing optics element (e.g., a condenser lens or a concave mirror) to focus the spectral beam at the aperture.

[0089] In some embodiments, the portion collected by the first spectral beam (e.g., having a wavelength greater than 400 nm and less than 700 nm) is less than the portion collected by the second spectral beam (e.g., having a wavelength less than 400 nm). In some embodiments, the portion collected by the first spectral beam is less than the portion collected by the third spectral beam (e.g., having a wavelength greater than 700 nm).

[0090] At operation 840, method 800 can continue by the following steps: a second optics device forms an output beam based on the collected portion of each of the spectral beams. For example, the second optics device may include a collimating optics element (e.g., a condenser lens or a concave mirror) to collimate each of the spectral beams passing through the aperture. In some embodiments, the second optics device may include a dispersive (compensating) optics element to combine the collimated spectral beams. As a result, the spectral distribution of the (combined) output beam may differ from the spectral distribution of the input beam of light. In some embodiments, the second optics device may also include a second focusing optics element to form an output beam based on the combined multiple collimated spectral beams. For example, the second focusing optics element (e.g., a condenser lens or a concave mirror) can focus the combined collimated spectral beams at the opening of the output fiber.

[0091] In some embodiments, the second optics can direct the output beam toward the photodetector. In some embodiments, the second optics can direct the output beam toward a substrate (or other target). The output beam incident on the substrate can cause the reflected beam to propagate away from the substrate. The photodetector can then receive (directly or via an optical fiber) the reflected beam to determine the spectral content of the reflected beam.

[0092] Figure 9This is a flowchart of one possible implementation of a method 900 for forming an output beam with a target time-averaged spectral profile for precise optical characterization of a target within a processing chamber, according to some embodiments of this disclosure. In some embodiments, method 900 may be performed using the systems and elements described in Figures 1 and 7, or any combination thereof. In some embodiments, some or all blocks of method 900 may be performed in response to instructions from computer device 118 or microcontroller 152. In some embodiments, method 900 may be performed while an optical target (e.g., a substrate or calibration device) is being processed within a substrate manufacturing apparatus.

[0093] Method 900 may include the following steps: receiving an input beam of light from a light source (operation 910). In some embodiments, the input beam of light may be a beam reflected from an optical target. At operation 920, method 900 may continue by the following step: guiding the input beam through a dynamic filtering device. The dynamic filtering device may include a set of color filters. Each of the color filters can transmit light within a specific wavelength range to the filter to a greater extent than light having wavelengths outside this range. (Spectral components having wavelengths outside this range may be absorbed or reflected by the material of the corresponding color filter.) Each of the color filters may be exposed to the input beam for a limited exposure time before the next color filter in a plurality of color filters is exposed to the input beam. For example, the color filters may be exposed to the input beam sequentially. In some embodiments, the color filters may be arranged in a circular pattern within the dynamic filtering device (e.g., Figure 7A (as illustrated in the diagram), and is sequentially exposed to the input beam by applying rotational motion to the dynamic filter device (e.g., by a motor).

[0094] At operation 930, method 900 can continue by the following steps: collecting a set of spectral beams, each of which is obtained by transmitting the input beam through a corresponding color sensor. Each of the transmitted spectral beams can be a pulsed beam with a duration determined by the exposure time of the corresponding sensor. Thus, the output beam can have a temporal periodicity of a period T. The output beam can be a combination of spectral beams (pulses), each spectral pulse having a duration equivalent to a portion of the period T, and this duration being equal to the exposure time of the corresponding color filter. As explained above in more detail with reference to Figure 7, the exposure time of each of the color filters can be determined based on the spectral distribution of the input beam and the desired target spectral distribution of the output beam.

[0095] At operation 940, method 900 may continue by the following steps: passing the collected multiple spectral beams to at least one of a photodetector or optical target located within the substrate manufacturing apparatus.

[0096] Figure 10 A block diagram depicting an example processing device 1000 operating according to one or more aspects of this disclosure. In one embodiment, the processing device 1000 may be... Figure 1A This is part of a computer device 118. The example processing device 1000 can be connected to other processing devices in a LAN, internal network, external network, and / or interconnection network. The processing device 1000 can be a personal computer (PC), set-top box (STB), server, network router, switch or bridge, or any device capable of executing a set of instructions (sequentially or otherwise) specifying the actions to be taken by the device. Furthermore, although only a single example processing device is illustrated, the term "processing device" should also be considered as including any collection of processing devices (e.g., computers) that individually or jointly execute a set (or more) of instructions to perform any or more of the methods discussed herein.

[0097] Example processing device 1000 may include processor 1002 (e.g., CPU), main memory 1004 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM) (e.g., synchronous DRAM (SDRAM)) etc.), static memory 1006 (e.g., flash memory, static random access memory (SRAM) etc.), and auxiliary memory (e.g., data storage device), which can communicate with each other via bus 1030.

[0098] Processor 1002 represents one or more general-purpose processing devices, such as microprocessors, central processing units, etc. More specifically, processor 1002 may be a Complex Instruction Set Computing (CISC) microprocessor, a Reduced Instruction Set Computing (RISC) microprocessor, a Very Long Instruction Word (VLIW) microprocessor, a processor implementing other instruction sets, or a processor implementing a combination of instruction sets. Processor 1002 may also be one or more special-purpose processing devices, such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), network processors, etc. According to one or more aspects of this disclosure, processor 1002 may be configured to execute instructions that implement method 800 to perform spectral shaping on an input beam for precise optical characterization of a target within a device fabrication system, and / or implement method 900 to form an output beam with a target time-averaged spectral distribution.

[0099] The example processing device 1000 may further include a network interface device 1008, which can be communicatively coupled to a network 1020. The example processing device 1000 may further include a video display 1010 (e.g., a liquid crystal display (LCD), a touch screen, or a cathode ray tube (CRT)), an alphanumeric input device 1012 (e.g., a keyboard), an input control device 1014 (e.g., a cursor control device, a touch screen control device, a mouse), and a signal generating device 1016 (e.g., an acoustic speaker).

[0100] Data storage device 1018 may include a computer-readable storage medium (or more specifically a non-transitory computer-readable storage medium) 1028 on which one or more sets of executable instructions 1022 are stored. According to one or more aspects of this disclosure, the executable instructions 1022 may include executable instructions for implementing method 800 to perform spectral shaping on an input beam for precise optical characterization of a target within a device manufacturing system, and / or executable instructions for implementing method 900 to form an output beam with a target time-averaged spectral distribution.

[0101] The executable instructions 1022 may also reside wholly or at least partially in main memory 1004 and / or processor 1002 during execution by the example processing device 1000, which also constitute computer-readable storage media. The executable instructions 1022 may further be transmitted or received over a network via network interface device 1008.

[0102] Although the computer-readable storage medium 1028 is in Figure 10 While referred to as a single medium, the term "computer-readable storage medium" should also be considered to include a single medium or multiple media (e.g., a centralized or distributed database, and / or associated cache memory and server) that store one or more sets of operating instructions. The term "computer-readable storage medium" should also be considered to include any medium capable of storing or encoding a set of instructions for execution by a machine, such that a machine performs any or more of the methods described herein. Therefore, the term "computer-readable storage medium" should be considered to include (but is not limited to) solid-state storage as well as optical and magnetic media.

[0103] It should be understood that the above description is intended to be illustrative and not restrictive. Many other examples of implementation will become apparent to those skilled in the art after reading and understanding the above description. While this disclosure describes specific examples, it will also be appreciated that the systems and methods of this disclosure are not limited to the examples described herein and can be practiced with modifications to the scope of the appended claims. Therefore, the specification and drawings should be regarded as illustrative rather than restrictive. The scope of this disclosure will therefore be determined with reference to the appended claims and the full scope of their equivalents.

[0104] The methods, hardware, software, firmware, or code described above can be implemented via instructions or code stored on a machine-accessible, machine-readable, computer-accessible, or computer-readable medium and executable by a processing element. "Memory" includes any mechanism that provides (i.e., stores and / or transmits) information in a form readable by a machine (e.g., a computer or electronic system). For example, "memory" includes random access memory (RAM), such as static RAM (SRAM) or dynamic RAM (DRAM); ROM; magnetic or optical storage media; flash memory devices; electrical storage devices; optical storage devices; acoustic storage devices; and any type of tangible machine-readable medium suitable for storing or transmitting electronic instructions or information in a form readable by a machine (e.g., a computer).

[0105] Throughout the specification, references to "one embodiment" or "implementation:" mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in at least one embodiment of this disclosure. Therefore, the phrases "in one embodiment" or "in an embodiment" appearing throughout the specification do not necessarily refer to the same embodiment. Furthermore, particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0106] In the foregoing description, detailed descriptions have been provided with reference to specific exemplary embodiments. However, it will be apparent that various modifications and changes can be made to these embodiments without departing from the broader spirit and scope of the disclosure set forth in the appended claims. Therefore, the description and drawings should be considered illustrative rather than restrictive. Furthermore, the above use of terms such as embodiments, implementations, and / or other exemplary language does not necessarily refer to the same embodiments or the same examples, but may refer to different and dissimilar embodiments as well as the same embodiments.

[0107] The terms “example” or “exemplary” are used herein to mean as an example, instance, or illustration. Any aspect or design described herein as an “example” or “exemplary” is not necessarily to be construed as preferred or advantageous relative to other aspects or designs. Rather, the use of the terms “example” or “exemplary” is intended to present the concept in a concrete manner. As used herein, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless otherwise specified or clearly apparent from the context, “X includes A or B” is intended to mean either of the natural inclusive arrangements. That is, if X includes A; X includes B; or X includes both A and B, then “X includes A or B” is satisfied in any of the foregoing cases. Furthermore, unless otherwise specified or clearly apparent from the context that a singular form is involved, the article “a” as used herein and in the appended claims should generally be interpreted as meaning “one or more.” And the use of the terms “implementation” or “an implementation” or “a mode of implementation” is never intended to indicate the same implementation or mode of implementation unless so described. Furthermore, terms such as “first,” “second,” “third,” “fourth,” etc., as used in this article are intended as labels to distinguish different elements and may not necessarily have an ordering meaning based on their numerical markings.

Claims

1. A system for optical characterization, comprising: a first optical device to: receive an input beam of light, the input beam comprising a plurality of spectral components of light; and disperse the input beam into a plurality of spectral beams, wherein each of the plurality of spectral beams comprises one of the plurality of spectral components of light, and wherein each of the plurality of spectral beams propagates along a spatial path that is different from a spatial path of each of the other spectral beams of the plurality of spectral beams; and a second optical device to: collect a portion of each of the plurality of spectral beams, wherein the portion collected is dependent on the spatial path of the respective spectral beam; and form an output beam of light from the collected portion of each of the plurality of spectral beams, wherein a spectral distribution of the output beam is different from a spectral distribution of the input beam of light, wherein the second optical device comprises an aperture having a width that varies with distance along the aperture, wherein each of the plurality of spectral beams will pass through the aperture at a different location than each of the other spectral beams, and wherein the aperture has an array of movable vanes, each movable vane of the array of movable vanes being movable to adjust the width of the aperture at a respective distance along the aperture.

2. The system of claim 1, wherein the first optical device comprises a prism to disperse the input beam into the plurality of spectral beams.

3. The system of claim 1, wherein the first optical device comprises a grating to disperse the input beam into the plurality of spectral beams.

4. The system of claim 1, wherein the second optical device comprises a first focusing optical element to focus the plurality of spectral beams dispersed by the first optical device at the aperture.

5. The system of claim 4, wherein the first focusing optical element comprises at least one of a condenser lens or a concave mirror.

6. The system of claim 4, wherein the second optical device further comprises a collimating optical element to collimate each of the plurality of spectral beams passing through the aperture, and wherein the collimating optical element is one of a condenser lens or a concave mirror.

7. The system of claim 6, wherein the second optical device further comprises a dispersive optical element to combine the collimated plurality of spectral beams.

8. The system of claim 7, wherein the second optical device further comprises a second focusing optical element to form the output beam from the combined collimated plurality of spectral beams.

9. The system of claim 8, wherein the second focusing optical element is to focus the combined collimated plurality of spectral beams at an opening of an output optical fiber. ​ 10. The system of claim 1, wherein a collected portion of a first spectral beam of the plurality of spectral beams is less than a collected portion of a second spectral beam of the plurality of spectral beams, wherein the first spectral beam comprises spectral components having wavelengths greater than 400 nm and less than 700 nm, and wherein the second spectral beam comprises spectral components having wavelengths greater than 700 nm.

11. The system of claim 10, wherein a collected portion of a third spectral beam of the plurality of spectral beams is more than the collected portion of the first spectral beam, wherein the third spectral beam comprises spectral components having wavelengths less than 400 nm.

12. The system of claim 1, wherein the collected portion of the first spectral beam of the plurality of spectral beams is less than the collected portion of the second spectral beam of the plurality of spectral beams, wherein the first spectral beam comprises spectral components having wavelengths greater than 400 nm and less than 700 nm, and wherein the second spectral beam comprises spectral components having wavelengths less than 400 nm.

13. The system of claim 1, wherein the first optical device comprises a first waveguide having an opening to disperse the input beam delivered to the first waveguide into the plurality of spectral beams.

14. The system of claim 13, wherein the first waveguide is an optical fiber.

15. The system of claim 13, wherein the second optical device comprises a second waveguide having an opening facing the opening of the first waveguide, wherein an axis of the second waveguide is laterally offset from an axis of the first waveguide.

16. The system of claim 1, wherein the first optical device comprises a first prism to disperse the input beam delivered to the first prism into the plurality of spectral beams, and the second optical device comprises a second prism, wherein the second prism is laterally offset from the second prism.

17. The system of claim 1, further comprising: a light source to generate the input beam received by the first optical device; and a light detector to receive a light beam reflected from a substrate located within one of a processing chamber or a transfer chamber of a substrate manufacturing apparatus, wherein the reflected light beam is caused by the output beam incident on the substrate.

18. The system of claim 1, further comprising: a light source to direct an incident beam onto a substrate located within one of a processing chamber or a transfer chamber of a substrate manufacturing apparatus; wherein the input beam is a light beam reflected from the substrate and caused by the incident beam; and a light detector to receive the output beam.

19. A system for optical characterization, comprising: a light source to direct an incident beam onto a substrate located within one of a processing chamber or a transfer chamber of a substrate manufacturing apparatus, wherein the incident beam will cause a beam to be reflected from the substrate; a first optical device to: receiving the reflected beam of light, the reflected beam comprising a plurality of spectral components of light; and dispersing the received reflected beam into a plurality of spectral beams, wherein each of the plurality of spectral beams comprises one of the plurality of spectral components of light, and wherein each of the plurality of spectral beams propagates along a spatial path that is different from a spatial path of each of the other spectral beams of the plurality of spectral beams; a second optical device to: collect a portion of each of the plurality of spectral beams, wherein the collected portion depends on the spatial path of the respective spectral beam; and a light detector to receive the collected portion of the spectral beams, wherein the second optical device comprises an aperture having a width that varies as a distance along the aperture, wherein each of the plurality of spectral beams will pass through the aperture at a different location from each of the other spectral beams, and wherein the aperture has an array of movable vanes, each movable vane of the array of movable vanes being movable to adjust the width of the aperture at a respective distance along the aperture.

20. A method for optical characterization, comprising the steps of: receiving an input beam of light, the input beam comprising a plurality of spectral components of light; dispersing the input beam into a plurality of spectral beams using a first optical device, wherein each of the plurality of spectral beams comprises one of the plurality of spectral components of light, and wherein each of the plurality of spectral beams propagates along a spatial path that is different from a spatial path of each of the other spectral beams of the plurality of spectral beams; collecting a portion of each of the plurality of spectral beams using a second optical device, wherein the collected portion depends on the spatial path of the respective spectral beam; and forming an output beam of light from the collected portion of each of the plurality of spectral beams, wherein a spectral distribution of the output beam is different from a spectral distribution of the input beam of light, wherein the second optical device comprises an aperture having a width that varies as a distance along the aperture, wherein each of the plurality of spectral beams will pass through the aperture at a different location from each of the other spectral beams, and wherein the aperture has an array of movable vanes, each movable vane of the array of movable vanes being movable to adjust the width of the aperture at a respective distance along the aperture.

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