Endpoint detection system to enhance spectral data acquisition

Abstract

An endpoint detection system is provided to enhance spectral data acquisition. [Solution] The optical bundle is coupled to a light source configured to generate incident light and includes two or more sets of optical fibers, each containing an output optical fiber and an input optical fiber. The input optical fibers are positioned within the optical bundle at a pair angle with respect to each output optical fiber. The optical bundle is coupled to a collimator assembly that includes an achromatic lens. The achromatic lens receives a first light beam of incident light from a first output optical fiber, directs its spectral components to first and second portions of the substrate surface, collects the reflected spectral components generated on the substrate surface, and transmits the reflected spectral components to the first input fiber of the optical bundle. The first input fiber transmits the reflected spectral components to a photodetector component. A processing device coupled to the photodetector component determines the reflectance of the substrate surface based on the reflected spectral components.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to manufacturing systems, and more particularly to endpoint detection systems for enhancing spectral data collection. Background

[0002] The manufacture of microelectronics and integrated circuit devices often involves performing numerous operations on semiconductor, dielectric, and conductive substrates. In some examples, single crystals, semiconductor films, coatings, and many other materials are used in the manufacture of electronic devices and other practical applications. Since selected types of atoms are added to (e.g., by deposition) or removed from (e.g., by etching) the substrate, efficient and accurate endpoint monitoring techniques and systems are valuable. Underprocessing (e.g., insufficient deposition, insufficient etching) and overprocessing (e.g., excessive deposition, overprocessing) can result in substandard, malfunctioning devices. Thus, optical control systems that can monitor various stages of device manufacture in real time can significantly improve product quality, which is particularly useful considering the ever-increasing demand for high-quality semiconductor devices. Summary

[0003] Some of the embodiments described cover an endpoint detection system. The endpoint detection system includes a light source component configured to generate incident light. Furthermore, the endpoint detection system includes an optical bundle coupled to the light source. The optical bundle includes a first set of optical fibers, including a first exit optical fiber and a first incident optical fiber. The first exit optical fiber is positioned at a pair angle with respect to the first incident optical fiber. The optical bundle further includes a second set of optical fibers, including a second exit optical fiber and a second incident optical fiber. The second exit optical fiber is positioned at a pair angle with respect to the second incident optical fiber. The first and second exit optical fibers are configured to receive incident light from the light source. Furthermore, the endpoint detection system includes a collimator assembly coupled to the optical bundle, the collimator assembly includes an achromatic lens. The achromatic lens is configured to respond to the reception of a first light beam of incident light from the first exit optical fiber and to direct a first set of spectral components of the first light beam to a first portion of the substrate surface. Furthermore, the achromatic lens is configured to direct a second set of spectral components of the first light beam to a second portion of the substrate surface. The first portion is substantially the same as the second portion. Furthermore, the achromatic lens is configured to collect the first set of reflected spectral components and the second set of reflected spectral components of the light from the substrate surface. The set of reflected spectral components of the light is generated by the first set of spectral components directed to the first portion of the substrate surface, and the second set of reflected spectral components of the light is generated by the second set of spectral components directed to the second portion of the substrate surface. Furthermore, the achromatic lens is configured to transmit the first set of reflected spectral components and the second set of reflected spectral components to the first incident optical fiber of the optical fiber bundle. Furthermore, the optical bundle includes a photodetector component coupled to the optical bundle. The photodetector component is configured to receive the first set of reflected spectral components and the second set of reflected spectral components from the first incident optical fiber. Furthermore, the optical bundle includes a processing device communicably coupled to the photodetector component.The processing device is configured to determine the reflectance of the substrate surface based on a first set of reflectance spectral components and a second set of reflectance spectral components.

[0004] In some embodiments, a manufacturing system is provided. The manufacturing system includes a processing chamber and a substrate placed within the processing chamber. Furthermore, the manufacturing system includes an endpoint detection system coupled to the processing chamber and configured to determine the reflectance of the substrate surface. The endpoint detection system includes a light source component configured to generate incident light. Furthermore, the endpoint detection system includes an optical bundle coupled to the light source. The optical bundle includes a first set of optical fibers, including a first output optical fiber and a first input optical fiber. The first output optical fiber is positioned at a pair angle with respect to the first input optical fiber. Furthermore, the optical bundle includes a second set of optical fibers, including a second output optical fiber and a second input optical fiber. The second output optical fiber is positioned at a pair angle with respect to the second input optical fiber. The first and second output optical fibers are configured to receive incident light from the light source. Furthermore, the endpoint detection system includes a collimator assembly coupled to the optical bundle, the collimator assembly includes an achromatic lens. The achromatic lens is configured to direct a first set of spectral components of the first light beam to a first portion of the substrate surface in response to the reception of a first light beam of incident light from a first exit optical fiber. Furthermore, the achromatic lens is configured to direct a second set of spectral components of the first light beam to a second portion of the substrate surface. The first portion is substantially the same as the second portion. Furthermore, the achromatic lens is configured to collect a first set of reflected spectral components and a second set of reflected spectral components of light from the substrate surface. The set of reflected spectral components of light is generated by the first set of spectral components directed to the first portion of the substrate surface, and the second set of reflected spectral components of light is generated by the second set of spectral components directed to the second portion of the substrate surface. Furthermore, the achromatic lens is configured to transmit the first set of reflected spectral components and the second set of reflected spectral components to the first incident optical fiber of the optical fiber bundle. Furthermore, the optical bundle includes a photodetector component coupled to the optical bundle. The optical detection component is configured to receive a first set of reflection spectral components and a second set of reflection spectral components from the first incident optical fiber.Furthermore, the optical bundle includes a processing device communicatively coupled to the photodetector component. The processing device is configured to determine the reflectance of the substrate surface based on a first set of reflectance spectral components and a second set of reflectance spectral components.

[0005] In some embodiments, a method for enhanced spectral data acquisition is provided. This method includes transmitting incident light through a first output optical fiber of a first set of optical fibers in an optical bundle and a second output optical fiber of a second set of optical fibers in an optical bundle. Furthermore, the first set of optical fibers includes a first input optical fiber positioned at a pair angle with respect to the first output optical fiber. Furthermore, the second set of optical fibers includes a second input optical fiber positioned at a pair angle with respect to the second output optical fiber. Furthermore, this method includes directing a first set of spectral components of a first optical beam of the incident light transmitted through the first output optical fiber to a first portion of the substrate surface and a second set of spectral components of the first optical beam to a second portion of the substrate surface via an achromatic lens of a collimator assembly. The first portion is substantially the same as the second portion. Furthermore, this method includes receiving the first set of reflected spectral components and the second set of reflected spectral components collected by the achromatic lens of the collimator assembly from a photodetector component coupled to the optical bundle. The first set of reflectance spectral components is generated by a first set of spectral components directed to a first portion of the substrate surface. The second set of reflectance spectral components is generated by a second set of spectral components directed to a second portion of the substrate surface. The first set of reflectance spectral components and the second set of reflectance spectral components are transmitted from the achromatic lens to the photodetector component via the first incident optical fiber of the first set of optical fibers. Furthermore, this method includes determining the reflectance of the substrate surface based on the first set of reflectance spectral components and the second set of reflectance spectral components. [Brief explanation of the drawing]

[0006] This disclosure is not limiting and is illustrated by the accompanying drawings as examples, where similar reference numerals indicate similar elements. It should be noted that any “one” embodiment or different references to one embodiment in this disclosure do not necessarily refer to the same embodiment, and such references mean at least one. [Figure 1] An exemplary computer system architecture according to the aspects of this disclosure is shown. [Figure 2] This is a schematic top view of an exemplary manufacturing system according to an aspect of the present disclosure. [Figure 3] This document illustrates an endpoint detection system according to the embodiments of this disclosure. [Figure 4A] ~ [Figure 4B] This figure shows an optical bundle and achromatic assembly of an endpoint detection system according to an aspect of the present disclosure. [Figure 5A] A cross-sectional view of an example of an optical bundle according to an aspect of this disclosure is shown. [Figure 5B] A cross-sectional view of another example of an optical bundle according to an aspect of this disclosure is shown. [Figure 6A] ~ [Figure 6C] This disclosure describes enhanced spectral data collection obtained by an endpoint detection system according to the embodiments of this disclosure. [Figure 7] This is a flowchart of a method for collecting spectral data using an endpoint detection system according to the aspects of this disclosure. [Figure 8] This is a flowchart of a method for training a machine learning model using spectral data collected by an endpoint detection system in multiple processing chambers, according to an aspect of the present disclosure. [Figure 9] A block diagram of an exemplary computer system operating according to one or more aspects of this disclosure is shown. Detailed description of the embodiment

[0007] Embodiments of this disclosure relate to endpoint detection systems for enhancing spectral data acquisition. Substrate processes (e.g., deposition processes, etching processes, etc.) can be performed on a substrate in a processing chamber of a manufacturing system. The endpoint of a substrate process refers to a point in the process where the substrate profile corresponds to (i.e., matches or substantially matches) a target substrate profile. For example, a mask containing the pattern of a target substrate profile can be used during an etching process of a substrate (e.g., a silicon wafer). The mask is placed on the surface of the wafer and exposed to a reactive environment (e.g., wet or dry etching) to remove portions of the substrate not protected by the mask. The endpoint of an etching process also refers to a point in the etching process where the substrate profile corresponds to the pattern of the target substrate profile provided by the mask.

[0008] Deviations from process procedures can cause variations in substrate process speed and / or uniformity. For example, changes in the etching environment or differences in photomask patterns can lead to variations in etching speed and uniformity across the entire substrate surface and between etching processes of multiple substrates. Tracking and responding to such variations requires a precise and adjustable optical endpoint system capable of collecting accurate and substantial optical response data characterizing the substrate surface at various points in the substrate process. The pursuit of precision is further driven by the reduction in the size of microelectronic devices, the increasing complexity of photomask designs, and the growing demand for device uniformity. Existing optical systems for endpoint control often cannot meet these increasing technical demands.

[0009] Aspects and embodiments of the present disclosure address this and other drawbacks of the prior art by providing an endpoint detection system for enhancing spectral data acquisition. The endpoint detection system can be coupled to or located within a processing chamber and can be configured to collect spectral data of a substrate during the substrate process. Spectral data refers to data relating to the intensity of the energy wave (i.e., the intensity or amount of energy) detected for each wavelength of light reflected from the surface of the substrate. The optical bundle of the endpoint detection system is coupled to a light source component, a photodetector, and a collimator assembly. The optical bundle includes at least a first set of optical fibers, including a first exit fiber and a first incident fiber positioned at a pair angle with respect to the first exit fiber. Furthermore, the optical bundle includes at least a second set of optical fibers, including a second exit fiber and a second incident fiber positioned at a pair angle with respect to the first exit fiber. The pair angle is between approximately 175 degrees and approximately 180 degrees.

[0010] A light source generates incident light and transmits it to a collimator assembly via a first and second output fiber. The collimator assembly includes achromatic lenses configured to convert the incident light transmitted by the first output fiber into a first incident light beam and the incident light transmitted by the second output fiber into a second incident light beam. Each incident light beam has a uniform spatial profile over a wide range of wavelengths. Each light beam may contain multiple sets of spectral components, each associated with a different wavelength range. The collimator assembly directs the first set of spectral components of the first light beam to a first portion of the substrate surface and the second set of spectral components of the first light beam to a second portion of the substrate surface. The collimator assembly also directs the first set of spectral components of the second light beam to a third portion of the substrate surface and the second set of spectral components of the second light beam to a fourth portion of the substrate surface.

[0011] The first and second reflected light beams are transmitted from the substrate surface to an achromatic lens. The first reflected light beam includes a first set of reflected spectral components generated by a first set of spectral components of the first light beam and a second set of reflected spectral components generated by a second set of spectral components of the first light beam. The second reflected light beam includes a first set of reflected spectral components generated by a first set of spectral components of the second light beam and a second set of reflected spectral components generated by a second set of spectral components of the second light beam. The achromatic lens transmits the first reflected light beam to the first incident fiber of the optical bundle and the second reflected light beam to the second incident fiber. A photodetector coupled to the optical bundle receives the first and second reflected light beams and determines the reflectance of the first and second portions of the substrate surface (e.g., via a processing device coupled to the photodetector). The determined reflectances form the basis of the substrate's spectral data or can be included in the spectral data and can be used to detect the endpoint of the substrate process.

[0012] The endpoint detection system of this disclosure provides enhanced spectral data acquisition that is not possible with conventional endpoint detection systems. The optical bundle of the endpoint detection system of this disclosure enables the transmission of multiple incident light signals from the light source component to the substrate surface, and the transmission of multiple reflected light signals from the substrate surface to the photodetector, without the use of additional equipment (e.g., beam splitters) that may reduce the power of the transmitted signals. As a result, the optical bundle can collect reflected light more efficiently, reduce signal loss in the reflected light beam, and make the reflected light signal larger overall than that of conventional fiber optic cables. The collimator assembly of the endpoint detection system generates an incident light beam with a uniform spatial profile over a wide range of wavelengths. For example, the width of the incident light beam may be the same for both the 250 nm spectral component of the beam and the 750 nm spectral component of the beam. The enhanced uniformity enables more accurate measurement of the optical response of the target portion of the substrate surface in the processing chamber, thereby providing more accurate data that can more precisely determine the state of the substrate profile during the substrate process.

[0013] Figure 1 shows an exemplary computer system architecture 100 according to an aspect of the present disclosure. The computer system architecture 100 includes a client device 120, a manufacturing apparatus 122, a measuring apparatus 130, a prediction server 112 (e.g., generating prediction data, providing model adaptation, using a knowledge base, etc.), and a data store 150. The prediction server 112 may be part of the prediction system 110. Furthermore, the prediction system 110 may include server machines 170, 180. In some embodiments, the computer system architecture 100 may include, or be part of, a manufacturing system for processing substrates (e.g., the manufacturing system 200 in Figure 2).

[0014] The components of the client device 120, manufacturing equipment 122, measuring equipment 130, prediction system 110, and / or data store 150 can be interconnected via network 140. In some embodiments, network 140 is a public network providing client device 120 with access to prediction server 112, data store 150, and other publicly available computing devices. In some embodiments, network 140 is a private network providing client device 120 with access to manufacturing equipment 122, measuring equipment 130, data store 150, and other privately available computing devices. Network 140 may include one or more wide area networks (WANs), local area networks (LANs), wired networks (e.g., Ethernet networks), wireless networks (e.g., 802.11 networks or Wi-Fi networks), cellular networks (e.g., Long-Term Evolution (LTE) networks), routers, hubs, switches, server computers, cloud computing networks, and / or combinations thereof.

[0015] The client device 120 may include computing devices such as personal computers (PCs), laptops, mobile phones, smartphones, tablet computers, netbooks, network-connected televisions ("smart TVs"), network-connected media players (e.g., Blu-ray players), set-top boxes, over-the-top (OTT) streaming devices, and operator boxes.

[0016] The manufacturing apparatus 122 can produce products according to a recipe or perform an operation over a period of time. In some embodiments, the manufacturing apparatus 122 may include, or be part of, a processing tool that includes one or more stations (e.g., processing chambers, transport chambers, load locks, etc.) configured to perform different functions on the substrate. Furthermore, the manufacturing apparatus 122 may include an endpoint detection system 124 configured to detect the endpoint of a process performed on the substrate in the manufacturing apparatus 122. The endpoint of the substrate process means the point in the process where the substrate profile corresponds to (i.e., matches or substantially matches) a target profile. The endpoint detection system 124 may include one or more components configured to collect and / or generate spectral data related to one or more portions of the substrate profile during the substrate process. Spectral data means data related to the intensity of the detected wave (i.e., the intensity or amount of energy) of the energy for each wavelength of the detected wave.

[0017] In some embodiments, the endpoint detection system 124 may include an optical fiber bundle and collimator assembly configured to guide incident light from a light source to the surface of the substrate and transmit reflected light from the substrate surface to a photodetector component. The processing device of the endpoint detection system 124 can generate spectral data of the substrate profile based on the reflected light transmitted to the photodetector component. Based on the spectral data, the processing device of the endpoint detection system 124 can determine whether the endpoint of the substrate process has been reached. In response to the determination that the endpoint of the substrate process has been reached, the endpoint detection system 124 can terminate the substrate process in the processing chamber. Further details regarding the endpoint detection system 124 are provided with reference to Figure 3.

[0018] In some embodiments, one or more stations of the manufacturing apparatus 122 may include sensors configured to generate and / or collect sensor data related to the manufacturing apparatus 122. The sensor data may include one or more values ​​such as temperature (e.g., heater temperature), space (SP), pressure, high frequency (HFRF), electrostatic chuck (ESC) voltage, current, flow rate, power, etc. The sensor data may be associated with or displayed with manufacturing parameters such as hardware parameters (e.g., settings or components of the manufacturing apparatus 122 (e.g., size, type, etc.)) or process parameters of the manufacturing apparatus 122. The sensor data may be provided while the manufacturing apparatus 122 is performing a substrate process. The sensor data may vary from substrate to substrate.

[0019] In some embodiments, the computer system architecture 100 may include a measuring device 130. The measuring device 130 may be configured to generate measurement data related to the substrate processed by the manufacturing device 122. The measurement data may include one or more values ​​such as film property data (e.g., wafer space film properties), dimensions (e.g., thickness, height, etc.), dielectric constant, dopant concentration, density, defects, etc. Furthermore, in some embodiments, the measurement data may include values ​​for one or more surface profile property data (e.g., etching rate, etching rate uniformity, limit dimensions of one or more features contained on the substrate surface, uniformity of limit dimensions across the substrate surface, edge placement error, etc.). The measurement data may be final or semi-final. The measurement data may differ from substrate to substrate.

[0020] In some embodiments, the measurement device 130 can include a measurement device that is separate (i.e., external) from the manufacturing device 122. For example, the measurement device 130 can be a stand-alone device that is not coupled to any station of the manufacturing device 122. In such embodiments, a user of the manufacturing system (e.g., an engineer, an operator, etc.) can remove a substrate processed by the manufacturing device 122 from the manufacturing device 122 and transfer the substrate to the measurement device 130 for measurement. In some embodiments, the measurement device 130 can transfer measurement data generated with respect to the substrate to a client device 120 coupled to the measurement device 130 via the network 140. In other or similar embodiments, a user of the manufacturing system can obtain measurement data of the substrate from the measurement device 130 and provide the measurement data to a computer system via a graphical user interface (GUI) of the client device 120. In additional or alternative embodiments, the measurement device 130 can be included as part of the manufacturing device 122. For example, the measurement device 130 can be included in the vacuum environment of a processing tool of the manufacturing device 122 (i.e., coupled to a transfer chamber). Such a measurement device is referred to as an in-line measurement device. In another example, the measurement device 130 can be included in the non-vacuum environment of the processing tool (i.e., coupled to a factory interface). Such a measurement device is referred to as an integrated measurement device.

[0021] The data store 150 may be memory (e.g., random access memory), drives (e.g., hard drives, flash drives), a database system, or other types of components or devices capable of storing data. The data store 150 may include multiple storage components (e.g., multiple drives or multiple databases) that can span multiple computing devices (e.g., multiple server computers). The data store 150 may store spectral data, non-spectral data (e.g., sensor data), measurement data, predictive data, etc. The spectral data may include historical spectral data (e.g., spectral data generated for previous substrates processed by the manufacturing apparatus 122 or other manufacturing apparatus connected to the data store 150 via the network 140) and / or current spectral data (spectral data generated for the current substrate being processed by the manufacturing apparatus 122). In some embodiments, the current spectral data may be data from which predictive data is generated. In some embodiments, the measurement data may include historical measurement data (e.g., measurement values ​​of previous substrates processed by the manufacturing apparatus 122 or other manufacturing apparatus). Furthermore, the data store 150 can also store contextual data related to the substrates being processed in the manufacturing system (e.g., recipe name, recipe step number, preventive maintenance indicator, operator, etc.).

[0022] In some embodiments, data store 150 can be configured to store data that is not accessible to users of the manufacturing system (e.g., operators, engineers, etc.). For example, spectral data, non-spectral data, and / or context data obtained regarding substrates processed in the manufacturing system may not be accessible to users of manufacturing apparatus 122. In some embodiments, all data stored in data store 150 is inaccessible to users, while in other or similar embodiments, some of the data stored in data store 150 is inaccessible to users, while another portion of the data stored in data store 150 is accessible to users. In some embodiments, the inaccessible data in data store 150 can be encrypted using an encryption mechanism unknown to the user (e.g., the data is encrypted using a secret encryption key). In other or similar embodiments, data store 150 can include a plurality of data stores in which data that is not accessible to users is stored in one or more first data stores and data that is accessible to users is stored in one or more second data stores.

[0023] In some embodiments, prediction system 110 includes server machine 170 and server machine 180. Server machine 170 includes a training set generator 172 that can generate a training data set (e.g., a set of data inputs and a set of target outputs) for training, validating, and / or testing machine learning model 190 or a set of machine learning models 190. In some embodiments, training set generator 172 can divide the training data into a training set, a validation set, and a test set.

[0024] The server machine 180 may include a training engine 182, a validation engine 184, a selection engine 185, and / or a test engine 186. An engine can mean hardware (e.g., circuits, dedicated logic, programmable logic, microcode, processing devices, etc.), software (e.g., instructions executed on processing devices, general-purpose computer systems, or dedicated machines, etc.), firmware, microcode, or a combination thereof. The training engine 182 can train a machine learning model 190 or a set of machine learning models 190. A machine learning model 190 can mean a model artifact generated by the training engine 182 using training data that includes training inputs and corresponding target outputs (the correct answer for each training input). The training engine 182 can find patterns in the training data that map training inputs to target outputs (predicted answers) and provide machine learning models 190 that capture these patterns. A machine learning model 190 may include a linear regression model, a partial least squares regression model, a Gaussian regression model, a random forest model, a support vector machine model, a neural network, a ridge regression model, etc.

[0025] The validation engine 184 can validate the trained machine learning models 190 using the corresponding feature sets of the validation set from the training set generator 172. The validation engine 184 can validate the accuracy of each of the trained machine learning models 190 based on the corresponding feature sets of the validation set. The validation engine 184 can discard trained machine learning models 190 that have accuracy that does not meet the threshold accuracy. In some embodiments, the selection engine 185 can select trained machine learning models 190 that have accuracy that meets the threshold accuracy. In some embodiments, the selection engine 185 can select the trained machine learning model 190 with the highest accuracy among the trained machine learning models 190. The test engine 186 can test the trained machine learning models 190 using the corresponding feature sets of the test set from the dataset generator 172. For example, a first trained machine learning model 190 trained using a first feature set of the training set can be tested using a first feature set of the test set. Based on the test set, the test engine 186 can determine which trained machine learning model 190 has the highest accuracy among all the trained machine learning models.

[0026] The prediction server 112 includes a prediction engine 114 that runs a trained machine learning model 190 on one or more inputs to obtain one or more outputs. For example, the prediction component 114 can provide spectral data and / or non-spectral data about a portion of the current substrate being processed by the manufacturing equipment 122 as input to the trained machine learning model 190, run the trained machine learning model 190 on that input, and obtain one or more outputs. In some embodiments, the outputs may include data indicating whether the current process on the current substrate has reached its endpoint. For example, one or more outputs may include measurement data of the current substrate. The measurement data can be used (e.g., by an endpoint detection system 124) to determine whether the endpoint of the current substrate process has been reached.

[0027] It should be noted that in some other implementations, the functionality of server machines 170 and 180, as well as the prediction server 112, can be provided by fewer machines. For example, in some embodiments, server machines 170 and 180 can be integrated into a single machine, and in some other or similar embodiments, server machines 170 and 180 and the prediction server 112 can be integrated into a single machine.

[0028] In general, functions described in one embodiment as being performed by server machine 170, server machine 180, and / or prediction server 112 can also be performed on client device 120. Furthermore, functions attributable to specific components can also be performed by multiple components, either different or working together.

[0029] In some embodiments, “User” can represent a single individual. However, other embodiments of the present disclosure encompass a “User” that is an entity controlled by multiple users and / or automated sources. For example, a set of individual users federated as a group of administrators can be considered a “User.”

[0030] Figure 2 is a schematic top view of an exemplary manufacturing system 200 according to an embodiment of the present disclosure. The manufacturing system 200 can perform one or more processes on a substrate 202. The substrate 202 may be a fixed-dimension planar article of any suitable rigidity suitable for manufacturing electronic devices or circuit components thereon (e.g., a silicon-containing disk or wafer, a patterned wafer, a glass plate, etc.).

[0031] The manufacturing system 200 may include a processing tool 204 and a factory interface 206 coupled to the processing tool 204. The processing tool 204 may include a housing 208 having a transport chamber 210 inside. The transport chamber 210 may include one or more processing chambers (also called process chambers) 214, 216, 218 arranged around it and coupled to it. The processing chambers 214, 216, 218 can be coupled to the transport chamber 210 via their respective ports (e.g., slit valves). The transport chamber 210 may also include a transport chamber robot 212 configured to transport substrates 202 between the processing chambers 214, 216, 218, load lock 220, etc. The transport chamber robot 212 may include one or more arms, each arm may include one or more end effectors at the end of each arm. The end effectors may be configured to handle specific objects such as wafers.

[0032] The processing chambers 214, 216, and 218 can be adapted to perform any number of processes on the substrate 202. The same or different substrate processes can be performed in each of the processing chambers 214, 216, and 218. Substrate processes can include atomic layer deposition (ALD), physical vapor deposition (PVD), chemical vapor deposition (CVD), etching, annealing, curing, pre-cleaning, removal of metal or metal oxide, etc. Other processes can be performed on the substrate therein. In some embodiments, an endpoint detection device 108 (e.g., the endpoint detection device of the endpoint detection system 124 described with respect to Figure 1) can be coupled to or placed within the processing chambers 214, 216, and 218, as described herein.

[0033] The load lock 220 can be coupled to the housing 208 and the transport chamber 210. The load lock 220 can be configured to interface with and couple to the transport chamber 210 and the factory interface 206 on one side. In some embodiments, the load lock 220 can have an environmentally controlled atmosphere that can be changed from a vacuum environment (for transporting substrates to and from the transport chamber 210) to an inert gas environment at or near atmospheric pressure (for transporting substrates to and from the factory interface 206).

[0034] The factory interface 206 can be any suitable enclosure, such as an equipment front-end module (EFEM). The factory interface 206 can be configured to receive substrates 202 from a substrate carrier 222 (e.g., a front-opening unified pod (FOUP)) docked to various load ports 224 of the factory interface 206. A factory interface robot 226 (shown by a dashed line) can be configured to transport substrates between the substrate carrier (also referred to as a container) and the load lock 220. In other embodiments and / or similar embodiments, the factory interface 206 can be configured to receive replacement parts from a replacement parts storage container 222.

[0035] Furthermore, the manufacturing system 200 can be connected to a client device (e.g., client device 120 in Figure 1) configured to provide information about the manufacturing system 200 to a user (e.g., an operator). In some embodiments, the client device can provide information to the user of the manufacturing system 200 via one or more graphical user interfaces (GUIs). For example, the client device can provide information via the GUI about the endpoints of the substrate processes performed in processing chambers 214, 216, and 218.

[0036] Furthermore, the manufacturing system 200 may include or be coupled to a system controller 228. The system controller 228 may be and / or include a computing device (e.g., a personal computer, a server computer, a programmable logic controller (PLC), a microcontroller, etc.). The system controller 228 may include one or more processing devices, which may be general-purpose processing devices (e.g., a microprocessor, a central processing unit, etc.). More specifically, the processing device may be a composite instruction set computing (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, a processor that executes other instruction sets, or a processor that executes a combination of instruction sets. The processing device may also be one or more dedicated processing devices (e.g., an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a digital signal processor (DSP), a network processor, etc.). The system controller 228 may include data storage devices (e.g., one or more disk drives and / or solid-state drives), main memory, static memory, a network interface, and / or other components. The system controller 228 can execute instructions to perform any one or more of the methods and / or embodiments described herein. In some embodiments, the system controller 228 can execute instructions to perform one or more operations in the manufacturing system 200 according to a process recipe. Instructions can be stored in a computer-readable storage medium, which may include main memory, static memory, secondary storage, and / or processing devices (during instruction execution).

[0037] In some embodiments, the processing device of the endpoint detection system 124 can correspond to the system controller 228. In such embodiments, the system controller 228 can receive spectral data from the equipment of the endpoint detection system 124 during the substrate process in processing chambers 214, 216, and 218. According to embodiments described herein, the controller 228 can determine, based on the received spectral data, whether the endpoint of the substrate process has been reached in processing chambers 214, 216, and 218. In other or similar embodiments, the processing device of the endpoint detection system 124 can be separated from the system controller 228. Thus, in response to the detection of the endpoint of the substrate process, the endpoint detection system 124 can send a command to the system controller 228, which can then terminate the substrate process in each of the processing chambers 314, 316, and 318.

[0038] Spectral data received from the equipment of the endpoint detection system 124 or other components of the manufacturing system 200 can be stored in the data store 250. The data store 250 may be included as a component within the system controller 228, or it may be a separate component from the system. As described with respect to Figure 1, in some embodiments, the data store 250 may be part of or include part of the data store 150.

[0039] Figure 3 shows an endpoint detection system 300 coupled to a processing chamber 310 according to an aspect of the present disclosure. The endpoint detection system 300 may correspond to the endpoint detection system 124 described with respect to Figure 1. The processing chamber 310 may correspond to any of the processing chambers 214, 216, and 218 described with respect to Figure 2. In some embodiments, the processing chamber 310 can be used in processes where a corrosive plasma environment is provided. For example, the processing chamber 310 may be a chamber for a plasma etcher or plasma etching reactor, a plasma cleaner, etc. In other or similar embodiments, the processing chamber 310 can be used in processes where a non-corrosive environment is provided. For example, the processing chamber 310 can be used as a chemical vapor deposition (CVD) chamber, a physical vapor deposition (PVD) chamber, an atomic layer deposition (ALD) chamber, an ion-assisted deposition (IAD) chamber, and other types of processing chambers. The processing chamber 310 can be configured to perform a process on the substrate 202 as described above.

[0040] In simple terms, the processing chamber 310 includes a chamber body 302 surrounding an internal volume 306, a lid 330, and / or a shower head (not shown). The chamber body 302 generally includes side walls 308 and a bottom 312. The shower head may include a shower head base and a gas distribution plate for the shower head. The lid 330 and / or shower head can be supported on the side walls 308 of the chamber body 302. The shower head (or lid 330) can be opened to allow access to the internal volume 306 of the processing chamber 310, and when closed, can provide a seal to the processing chamber 310. A gas panel (not shown) can be coupled to the processing chamber 310 to supply processing gas and / or cleaning gas to the internal volume 306 through the lid 330 and nozzles (e.g., through openings in the shower head or lid and nozzles), and / or the shower head. An exhaust port 326 can be defined within the chamber body 302, and the internal volume 306 can be coupled to a pump system 328. The pump system 328 may include one or more pumps and throttle valves used to evacuate and regulate the pressure in the internal volume 306 of the processing chamber. The substrate support assembly 348 is located within the internal volume 306, beneath the lid 330 and / or shower head. The substrate support assembly 348 holds the substrate 202 during processing. In one embodiment, the substrate support assembly 348 includes a base 352 that supports an electrostatic chuck 350.

[0041] The endpoint detection system 300 can be configured to optically monitor the environment of the internal volume 306 during the substrate process. As shown in Figure 3, the endpoint detection system 300 can be mechanically coupled to the chamber body 302 and optically interfaced with the environment of the internal volume 306 (i.e., via the chamber interface 370). In other or similar embodiments, one or more components of the endpoint detection system 300 can be located within the internal volume 306. The endpoint detection system 300 may include a collimator assembly 354, an optical fiber bundle 356, an optical component 362, a processing device 376, and, in some embodiments, a polarizer component 368. As shown in Figure 3, the collimator assembly 354 can be coupled to the chamber interface 370. In some embodiments, the chamber interface 370 may be an orifice, a converging or diverging lens, a transparent slab, or any other device or material capable of transmitting light between the collimator assembly 354 and the environment of the internal volume 306. Figure 3 shows the chamber interface 370 embedded within the lid 332, but the chamber interface 370 can be embedded in or coupled to any part of the processing chamber 310 (e.g., the side wall 308, the bottom 312, etc.).

[0042] The first end of the optical bundle 356 can be coupled to the collimator assembly 354, and the second end of the optical bundle 356 can be coupled to the optical component 362. The optical bundle 356 may include one or more outgoing fibers 358 and one or more ingress fibers 360, which are arranged within the insulating material of the optical bundle 356. Further details relating to the optical bundle 356 are provided herein. The optical component 362 may include a light source 364 configured to produce light. In this specification, “light” refers to electromagnetic radiation in any spectral range, including visible light, near infrared (IR), near ultraviolet (UV), etc. Furthermore, “light” may include unpolarized (e.g., natural) light, linearly polarized, circularly polarized, or elliptically polarized light, partially polarized light, focused light, divergent light, parallel light, etc. In some embodiments, the light source 364 may include a narrowband light source such as a light-emitting diode (LED), laser, or light bulb. In other or similar embodiments, the light source 364 may include broadband light. In some embodiments, the light source 364 may include two or more component light sources, such as multiple narrowband light sources, which together produce a broadband optical input. The light source 364 may include additional optical elements (i.e., filters, absorbers, polarizers, etc.) to control the spectral distribution and / or polarization of the light.

[0043] Light generated by the light source 364 (referred to herein as incident light) can be transmitted to the collimator assembly 354 via one or more output fibers 358 of the optical bundle 356. Upon receiving the incident light via the output fibers 358, the collimator assembly 354 can be configured to convert the incident light into one or more light beams. For example, the incident light can pass through one or more optical elements of the collimator assembly 354 (e.g., lenses, reflectors, filters, apertures, etc.). In some embodiments, the spatial characteristics of the light beam generated by the collimator assembly 354 may be the same for multiple spectral components of the light beam 372. For example, the diameter of the light beam 372 may be the same over a wide range of wavelengths λ of the various spectral components contained in the incident light. In existing endpoint detection systems, the diameter of a conventional light beam may vary depending on the wavelength λ. For example, the green component (λ=550nm) may have a diameter of 9nm, and the red component (λ=650nm) may have a diameter of 13nm. As a result, different spectral components propagate along different optical paths. This can lead to significant errors in the reflectance R(λ) of the resulting substrate, and therefore to an incorrect characterization of the surface of the substrate 202. In contrast, the collimator assembly 354 can generate a light beam 372 in which the diameter of the light is the same over a wide range of wavelengths λ. In some embodiments, the collimator assembly 354 can include one or more achromatic lenses. In such embodiments, the light beam 372 generated by the collimator assembly 354 can be achromatic. Further details regarding the collimator assembly 354 are provided with respect to Figures 4A-4B.

[0044] As shown in Figure 3, in some embodiments, the collimator assembly 354 may include a polarizer component 368. The polarizer component 368 is configured to polarize unpolarized (e.g., natural) light generated by the light source 364. For example, the polarizer component 368 can convert unpolarized incident light into linear, circular, or elliptical polarization. Although Figure 3 shows the polarizer component 368 as part of the collimator assembly 354, the polarizer component 368 can be coupled to any part of the endpoint detection system 300 that passes the incident light to the chamber interface 370. For example, the polarizer component 368 can be coupled to the outlet of the light source 364, the outlet of one or more outgoing optical fibers 358, or between the collimator assembly and the chamber interface 370.

[0045] The collimator 354 can guide a light beam 372 to the surface of the substrate 202, which is placed on the substrate support assembly 348, via the chamber interface 370. The light beam 372 is reflected off the surface of the substrate 202 as a reflected light beam 374 and can be received by the collimator assembly 354. One or more incident optical fibers 360 of the optical bundle 356 can transmit the reflected light beam 374 to the photodetector 366 of the optical component 362. The photodetector 366 may include one or more spectrometers, diffraction gratings, mirrors, lenses, photodiodes, and other devices. The photodetector 366 can determine one or more optical responses related to the surface of the substrate 202 based on the reflected light beam 374, either alone or in conjunction with the processing device 376. For example, the photodetector 366 and / or the processing device 376 can determine the reflectance R(λ), refractive index n(λ), or any other arbitrary light quantity that can be used to characterize the substrate 202 based on the reflected light 374. In some embodiments, the optical response can be used to characterize the substrate 202, including the polarization dependence of its reflectance, the rotation angle of the polarization plane during reflection, and the emission intensity. As described in this application, spectral data can mean data corresponding to the optical response of the reflected light 374 and / or the optical properties of the substrate 202 derived from the optical response of the reflected light 374.

[0046] In some embodiments, the processing device 376 may be included as part of a system controller (e.g., system controller 228) for a manufacturing system including a processing chamber 310. In such embodiments, the processing device 376 can store the spectral data generated for the substrate 202 in a data store (e.g., data store 250, etc.) coupled to the processing device 376. In other or similar embodiments, the processing device 376 may be a processing component separate from the system controller 228 but coupled to the system controller 228 via a network. The processing device 376 can transmit the generated spectral data to the system controller 228 for storage in each data store of the manufacturing system 200.

[0047] In some embodiments, the collimator assembly 354 may include a tilt adjustment mechanism 378 that allows adjustment of the collimator's optical axis. In some embodiments, the tilt mechanism 378 can facilitate centering of the collimator assembly 354 after maintenance or ensure consistency between chambers. In other or similar embodiments, the tilt mechanism 378 can facilitate adjustment of the optical axis for collecting spectral data from off-center portions of the substrate surface (e.g., edge portions of the substrate surface).

[0048] Figures 4A-4B show a collimator assembly 354 and an optical bundle 356 of an endpoint detection system 300 according to an aspect of the present disclosure. As described with respect to Figure 3, the collimator assembly 354 can be coupled to the chamber interface 370 of the processing chamber 310. In some embodiments, the collimator assembly 354 may include a collimator housing 410. The collimator housing 410 may include, or be coupled to, a chamber interface 412 configured to facilitate coupling of the collimator assembly 354 to the chamber interface 370. In some embodiments, the chamber interface 412 may be permanently fused to the collimator housing 410. In other or similar embodiments, the chamber interface 412 may be removably attached to the collimator housing 410 via screws, or may be retained to the collimator housing 410 by friction, retaining screws, pins, locking mechanisms, etc. The chamber interface 412 can be configured to fit into or be coupled to the receiving orifice of the processing chamber (e.g., the receiving orifice of the chamber interface 370). The chamber interface 412 and the receiving orifice of the processing chamber 310 can be sealed (i.e., by one or more gas-resistant seals or gaskets) to prevent gas leakage from the environment of the processing chamber 310.

[0049] As shown in Figure 4A, the optical bundle 356 may include at least a first set of optical fibers including a first exit fiber 358A and a first entrance fiber 360A, and a second set of optical fibers including a second exit fiber 358B and a second entrance fiber 358B. In other or similar embodiments, the optical bundle 356 may include any number of sets of optical fibers, each containing at least one exit fiber and one entrance fiber. In some embodiments, each optical fiber of the optical bundle 356 is arranged around a central point of the optical bundle 356. Figure 5A shows a cross-sectional view of an example of an optical bundle 356 according to an aspect of the present disclosure. As shown in Figure 5A, point 502 corresponds to the central point of the optical bundle 356. Each fiber of the first set and the second set of optical fibers can be arranged around the central point 502. As described above, in certain arrangements, the optical bundle 356 may include an insulating material 504 configured to maintain the position of each optical fiber. Furthermore, the insulating material 504 acts as a barrier between each optical fiber, minimizing or substantially eliminating crosstalk between adjacent optical fibers. In some embodiments, the insulating material 504 may include a plastic material (e.g., polytetrafluoroethylene (PTFE) material) and / or a ceramic material. In other or similar embodiments, the insulating material 504 may be air.

[0050] As shown in Figure 5A, the insulating material 504 maintains the first exit fiber 358A at a position radially away from the first inlet fiber 360A by a first pair angle 506. Additionally or alternatively, the insulating material 504 maintains the second exit fiber 358B at a position radially away from the second inlet fiber 360A by a second pair angle 506. In some embodiments, the first pair angle 506 and / or the second pair angle 508 are between approximately 175 degrees and approximately 185 degrees. In some embodiments, the first pair angle 506 and / or the second pair angle 508 are approximately 180 degrees. Furthermore, the insulating material 504 can maintain the first exit fiber 358A at a position radially away from the second exit fiber 358B by a first separation angle 510. Additionally or alternatively, the insulating material 504 can maintain the first incident fiber 360A at a distance of a second separation angle 512 from the second incident fiber.

[0051] The first separation angle 510 and / or the second separation angle 512 can be any angle less than approximately 180 degrees, as long as each outgoing fiber is diagonally opposite each incoming fiber by approximately 180 degrees. For example, the first separation angle 510 and / or the second separation angle 512 can be any angle from approximately 0.25 degrees to less than approximately 180 degrees. In some embodiments, the first separation angle 510 and the second separation angle 512 are equal. For example, the first separation angle 510 and the second separation angle 512 are between approximately 85 degrees and approximately 95 degrees. In another example, the first separation angle 510 and the second separation angle 512 are approximately 90 degrees. In other or similar embodiments, the first angle 510 and the second separation angle 512 do not have to be equal. For example, the first pair angle 506 between the first output fiber 358A and the first input fiber 360A may be approximately 180 degrees, and the second pair angle 508 between the second output fiber 358B and the second input fiber 360B may be approximately 175 degrees. Therefore, the first separation angle 510 between the first output fiber 358A and the second output fiber 358B may be approximately 90 degrees, and the second separation angle 512 between the first input fiber 360A and the second input fiber 360B may be approximately 85 degrees.

[0052] Figure 5B shows a cross-sectional view of another exemplary optical bundle 356 according to an aspect of the present disclosure. In some embodiments, the optical fibers of the optical bundle 356 may be arranged in pairs of fiber rows. A centerline 518 may cause the pairs of fiber rows to branch into a radiating section 520 and an incident section 522. As shown in Figure 5B, the radiating section 520 may include a first outgoing row 514A paired with a first incident row 514B of the incident section 522. Additionally or alternatively, the outgoing section 520 may include a second outgoing row 516A paired with a second incident row 516B. The first radiating row 514A may include one or more outgoing optical fibers paired with each incident optical fiber at a pair angle between about 175 degrees and about 185 degrees. For example, the first outgoing optical fiber 358A of the first radial array 514A can be paired with the first ingress optical fiber 360A of the first ingress array 514B at a pairing angle of approximately 180 degrees. Additionally or alternatively, the second radial array 516A may include one or more ingress optical fibers paired with each ingress optical fiber at a pairing angle between approximately 175 degrees and approximately 185 degrees.

[0053] Since the pairs of optical fibers (e.g., the first outgoing optical fiber 358A and the first incoming optical fiber 360A) are symmetric with respect to the center point 502, the order of the fiber pairs ensures that each pair of optical fibers is properly aligned. Furthermore, the first radiating column 514A and the first incoming column 514B are approximately equidistant from the center line 518. Thus, the center line 518 (i.e., the imaginary line) divides the optical bundle 356 into substantially equal cross-sectional areas.

[0054] Returning to Figure 4A, the optical bundle 356 is coupled to the collimator assembly 354 in the conduit 414 of the collimator housing 410. The incident light generated by the optical generator 362 in Figure 3 is transmitted from the optical generator 362 to the conduit 414 via the first output fiber 358A and the second output fiber 358B. In some embodiments, the conduit 414 may be located on the top of the collimator housing 410 (i.e., the guide cap). In other or similar embodiments, the conduit 414 may be located on other parts of the collimator housing 410 (e.g., the side walls of the collimator housing 410).

[0055] The collimator housing 410 defines an enclosure and can accommodate various optical elements of the collimator assembly 354 (e.g., an achromatic (broadband) lens 416, an optical filler (not shown), and / or an optical interface 418). The interface 418 may include an aperture, waveguide, lens, etc. The interface 418 may be configured to allow light to pass through but prevent the intrusion of contaminants. For example, after leaving the optical bundle 356, the incident light may pass through a slab or film of optically transparent material, or a diverging or converging lens that mechanically seals the conduit 414. The optical filler may include a transparent material configured to promote optical path consistency. For example, the optical filler may minimize the presence of air, moisture, and / or other possible contaminants along the optical path of the incident light and the light reflected from the surface of the substrate 202 (referred to as reflected light or output light). In some embodiments, the optical filler may be placed in the space between the optical interface 418 and the achromatic lens 416.

[0056] The achromatic lens 416 can be configured to convert the incident light transmitted from each output optical fiber 358 of the optical bundle 356 into its respective achromatic incident light beam. The achromatic light beam can be characterized based on the spectral content of the beam over multiple spectral ranges Δλ, such as a spectral range with a width Δλ = 100 nm (or 150 nm, 200 nm, or other wavelength ranges). The spectral ranges can be centered around a series of central wavelengths Δλ1, Δλ2, Δλ3, etc. In some embodiments, the ranges overlap and Δλ is greater than the distance between adjacent central wavelengths. In other or similar embodiments, Δλ is equal to the distance between central wavelengths (e.g., Δλ = λ3 - λ2). In other or similar embodiments, Δλ is greater than the distance between central wavelengths (i.e., the ranges do not overlap). In some examples, the widths of the ranges differ. Alternatively, the ranges can correspond to equal frequency intervals. In some examples, the range Δλ corresponds to the actual emission range of various light emitters of the light source 364. In other or similar examples, the range Δλ may be defined solely for characterization purposes and may not be limited to a specific physical light-emitting material.

[0057] The achromatic lens 416 may be a broadband lens designed to minimize chromatic aberration over a wide range of wavelengths. For example, the achromatic lens 416 may have multiple lenses made of different materials, some having higher dispersion of refractive index and others having lower dispersion. In some embodiments, the achromatic lens 416 is a doublet lens having two optical elements (e.g., a converging lens and a diverging lens). In other or similar embodiments, the achromatic lens 416 may be a triplet lens having three or more optical elements. The achromatic lens 416 can be designed for two, three, or more reference wavelengths to have the same focal point. For example, as described above, some or all of the reference wavelengths can be the central wavelength. This makes it possible to maintain low chromatic aberration even at wavelengths between the reference wavelengths. The focal lengths of the various elements of the achromatic lens 416 can be configured such that the light beam converted by the achromatic lens 416 is collimated (becomes nearly parallel) by the incident light transmitted by the exit fiber 358 of the optical bundle 356.

[0058] At the optical interface 418, incident light is received from the output fiber 358 and directed towards the achromatic lens 416. For example, the incident light signals 422A and 422B in Figure 4A represent incident light received at the optical interface 418 from the first output optical fiber 358A and directed towards the achromatic lens 416. In another example, the incident light signals 422A and 422B represent incident light received at the optical interface 418 from the second output optical fiber 358B. Once the incident light is received, the achromatic lens 416 can convert the incident light into an achromatic light beam. The collimator assembly 354 can direct the achromatic light beam to one or more portions of the surface 426 of the substrate 202. In one example, the achromatic lens 416 can convert optical signal 420A into an achromatic light beam 424A and optical signal 420B into an achromatic light beam 424B. The achromatic lens 416 is configured to convert the incident light into a collimated achromatic light beam, so that when directed toward the substrate surface 426, the achromatic light beam, light beam 424A, and light beam 424B become nearly parallel. Thus, the collimator assembly 354 can direct light beam 424A to a first portion 428 of the substrate surface 426 and light beam 424B to a second portion 430 of the substrate surface 426. Additionally or alternatively, the achromatic lens 416 can convert the incident light signal 422A into an achromatic light beam 432A and the incident light signal 422B into an achromatic light beam 32B. When directed toward the substrate surface 426, light beams 432A and 432B can become nearly parallel. Therefore, the collimator assembly can direct the optical beam 432A to a first portion 428 of the substrate surface 426 and the optical beam 432B to a second portion 430 of the substrate surface 426.

[0059] Considering the embodiments described above, each of the light beams 424A, 424B, 432A, and 432B can include a number of wavelength ranges. Each range can be characterized by its central wavelength and width. Thus, each range may contain multiple spectral components. In some embodiments, the spectral components can represent a continuum, so the number of spectral components within each range can be very large or even infinite. For example, each light beam 424A, 424B, 432A, and 432B has two sets of spectral components, where the first set of spectral components belongs to a first wavelength range and the second set belongs to a second wavelength range. However, it should be noted that according to the embodiments provided herein, each light beam can include more or fewer sets of spectral components. In some embodiments, the first wavelength range is within the wavelength interval of 400–700 nm, and the second wavelength range is outside the wavelength interval of 400–700 nm. It should be noted that, according to the embodiments provided herein, other first wavelength ranges and / or second wavelength ranges may be within or outside other wavelength intervals.

[0060] The achromatic lens 416 can be configured to direct each of the first set of spectral components to a first portion of the target section of the substrate surface 426, and each of the second set of spectral components to a second portion of the target section. For example, the achromatic lens 416 can direct the first set of spectral components of the light beam 424A to a first portion of the first section 428 of the substrate surface 426, and the second set of spectral components of the light beam 424A to a second portion of the first section 428. In some embodiments, the first portion of the first section 428 is substantially the same as the second portion of the first section 428. For example, the overlap between the second and first portions of the first section 428 may be at least 90% of each of the first and second portions. In another example, the overlap between the second and first portions of the first section 4289 may be at least 85% of each of the first and second portions. As described above, the achromatic lens 416 can direct the light beam 432A, in addition to the light beam 424A, to the first section 428 of the substrate surface 426. In such embodiments, the achromatic lens 416 can direct each of the spectral components of the first set of light beams 432A to a third portion of the first section 428, and direct the spectral components of the second set of light beams 432A to a fourth portion of the first section 428. In some embodiments, the third portion of the first section 428 may be the same as or different from the first and / or second portions of the first section 428. Similarly, the fourth portion of the first section 428 may be the same as or different from the first and / or second portions of the first section 428. The embodiments described with respect to light beams 424A and 432A can also be applied to light beams 424B and 432B.

[0061] Each achromatic light beam generated by the achromatic lens 416 can be directed toward the substrate surface 426 at an incident angle 434. When each achromatic light beam reaches the substrate surface 426 at an incident angle 424, the incident light beam is reflected toward the collimator assembly 354 at a reflection angle 436. The reflected ray is called the reflected beam. For example, the light beam 424A in the first section 428 of the substrate surface 426 is reflected toward the collimator assembly 354 as a reflected light beam 438A, and the light beam 424B in the second section 430 of the substrate surface 426 is reflected toward the collimator assembly 354 as a reflected light beam 438B. Since the light beams 424A and 424B directed toward the substrate surface 426 are approximately parallel, the reflected light beams 438A and 438B are similarly approximately parallel. Additionally or alternatively, the light beam 432A in the first section 428 of the substrate surface 426 is reflected toward the collimator assembly 354 as a reflected light beam 440A, and the light beam 432B in the second section 430 of the substrate surface 426 is reflected toward the collimator assembly 354 as a reflected light beam 440B. Since the light beams 432A and 432B directed toward the substrate surface 426 are substantially parallel, the reflected light beams 440A and 440B are similarly substantially parallel.

[0062] Each of the reflected light beams 438A, 438B, 440A, and 440B may contain a set of reflected spectral components generated by each set of spectral components of the corresponding incident light beams 424A, 424B, 432A, and 432B. For example, reflected light beam 438A may contain a first set of reflected spectral components generated by a first set of spectral components of light beam 424A, and a second set of reflected spectral components generated by a second set of spectral components of light beam 424A.

[0063] The light beam reflected from the substrate surface 426 is received by the achromatic lens 416 and transmitted to the optical interface 418. In some embodiments, the achromatic lens 416 can transmit the reflected light beam to an incident optical fiber paired with an outgoing optical fiber that provides the incident light that subsequently generates the reflected light beam. For example, the first outgoing optical fiber 358A transmits the incident light as optical signals 420A and 420B to the collimator assembly. The achromatic lens 416 converts optical signal 420A into a light beam 424A. The collimator assembly 354 directs the light beam 424A to the substrate surface 426 at an incident angle 434, and the light beam 424A is reflected from the first section 428 of the substrate surface 428 as a reflected light beam 438A. The achromatic lens 416 transmits the reflected light beam 438A to the optical interface 418, where the reflected light beam 438A is received by the first incident optical fiber 360A. According to the embodiment described above, the first incident optical fiber 360A transmits the received light beam 438A to the photodetector 366. Similarly, the first incident optical fiber 360A can receive the reflected light beam 438B from the achromatic lens 416. Additionally or alternatively, the second incident optical fiber 360B can receive the reflected light beam 440A and / or reflected light beam 440B from the achromatic lens 416, as described above.

[0064] In some embodiments, the chamber interface 370 may include a transparent window embedded within a portion of the processing chamber 310 (e.g., a lid 332). In some embodiments, the internal dimensions of the collimator housing 410 (e.g., diameter, etc.) may correspond to the size of the transparent window. For example, as shown in Figure 4B, the internal dimensions of the collimator housing 410 may correspond to the size of the transparent window 470. The transparent window 470 may include an inner surface 472 and an outer surface 474. In some embodiments, the collimator housing 410 may be coupled to the outside of the processing chamber 310, thereby substantially aligning the interior of the collimator housing 410 with the outer surface 474 of the transparent window 470.

[0065] In some embodiments, the inner surface 472 and outer surface 474 of the transparent window 470 may be substantially parallel. In other or similar embodiments, the inner surface 472 and outer surface 474 of the transparent window 470 may not be parallel. For example, as shown in Figure 4B, the outer surface 474 may be substantially parallel to the outer surface of the processing chamber 310. However, the inner surface 472 may be an inclined surface, meaning that the inner surface 472 is not parallel to the outer surface 474 and / or the outside of the processing chamber 310.

[0066] Figures 6A–6C illustrate enhanced spectral data acquisition obtained by an endpoint detection system according to embodiments of this disclosure. Figure 6A shows graph 600, which shows the magnitudes of various wavelengths of light detected by a conventional endpoint detection device compared to the endpoint detection device of the endpoint detection system 300 described herein. In some embodiments, graph 600 can represent the average magnitude of various wavelengths of light. The dashed line in Figure 6A represents the amplitude of the reflected light beam. This amplitude is, for example, the amplitude of the reflected light beams 438A, 438B, 440A, 440B, etc., described with respect to Figure 4, which are detected by a conventional endpoint detection device (i.e., an endpoint detection device that does not include the collimator assembly 354 and optical bundle 356 described herein). In some embodiments, the dashed line can represent the average amplitude of the reflected light beam. As shown in Figure 6A, the signals detected by a conventional endpoint detection device each fall within a specific magnitude range (i.e., between magnitude 0 nm and magnitude X nm). The solid line in Figure 6A represents the amplitude of the reflected light beam detected by the endpoint detection system 300 according to the embodiments described herein. In some embodiments, the solid line can represent the average amplitude of the reflected light beam. As seen in Figure 6A, the signals detected by the endpoint detection system 300 are within and outside a specific range of wavelengths that are detected by conventional endpoint detection devices. Therefore, the endpoint detection system 300 can detect reflected light beam signals that cannot be detected by conventional endpoints, and thus has significantly higher throughput and dynamic range (i.e., range of allowable or possible amplitude) than conventional endpoint detection devices. In some embodiments, the throughput of the endpoint detection system 300 can be as high as 60% higher than the throughput of conventional endpoint detection devices.

[0067] Figure 6B shows Graph 610, which includes several curves representing the normalized amplitudes of broadband wavelengths of optical signals or beams (e.g., beams 424A, 424B, 432A, 432B) directed onto the substrate surface by a conventional endpoint detection device. Line 612 represents the relative amplitude (i.e., the ratio of the new spectral intensity to the spectral intensity at perpendicular incidence) when the light is incident perpendicularly onto the wafer substrate. As shown in Figure 6B, the relative amplitudes of broadband wavelengths of the optical beam differ significantly as the incident angle increases (e.g., from a first angle to a second angle), as shown by lines 614, 616, and 618. Lines 614, 616, and 618 show that both the beam diameter and spectral shape change significantly when there is a slight misalignment of the beam. This difference can be caused by wavelength dispersion present in conventional endpoint detection devices, as mentioned above. Figure 6C shows a graph 620 containing several curves representing the normalized amplitudes of the broadband wavelengths of the optical beam directed onto the surface substrate by the endpoint detection system 300. As shown in Figure 6C, as represented by lines 614, 616, and 618, the relative amplitude of each wavelength of the optical beam is approximately the same across the broadband wavelengths of the optical beam as the incident angle increases from a first angle to a second angle. The distances between line 612 and lines 614, 616, and 618 in Figure 6C indicate that both the beam diameter and spectral shape remain the same, for example, if there is a slight misalignment of the beam. As described above with respect to Figures 4A to 4B, the achromatic lens of the collimator assembly can significantly reduce, and in some cases eliminate, the chromatic dispersion of the optical beam, which can result in the diameter of each wavelength of the optical beam being approximately the same. Furthermore, the configuration of the output and input fibers of the optical bundle 356 allows for the reduction and / or elimination of chromatic dispersion to be maintained even if the direction of the optical beam is deviated from the target portion of the substrate surface.

[0068] Figure 7 is a flowchart of Method 700 for collecting spectral data by an endpoint detection system according to an aspect of the present disclosure. Method 700 can be performed using the systems and / or components described in Figures 1 to 5B, or any combination thereof. In some embodiments, one or more operations of Method 700 can be performed using systems and / or components that may include hardware (circuits, dedicated logic, etc.), software (running on a general-purpose computer system or dedicated machine, etc.), firmware, or a combination thereof. In one embodiment, Method 700 can be performed by a controller for the manufacturing system (e.g., system controller 228). In other or similar implementations, Method 700 can be performed by one or more local controllers for the endpoint detection system 300 (e.g., local controllers for optical component 362 and / or collimator assembly 354, etc.). In yet another or similar implementations, one or more operations of Method 700 can be performed by one or more other machines not shown.

[0069] In block 710, incident light is transmitted through an optical bundle. In some embodiments, according to the embodiments described above, incident light can be generated by an optical component 362 and transmitted through an optical bundle 356. For example, incident light can be transmitted through a first output fiber of a first set of optical fibers and a second output fiber of a second set of optical fibers. Furthermore, the first set of optical fibers may include a first incident fiber positioned at a pair angle with respect to the first output fiber. The second set of optical fibers may include a second incident fiber positioned at a pair angle with respect to the second output fiber. In some embodiments, the pair angle may be between about 175 degrees and about 185 degrees. In some embodiments, the pair angle may be about 180 degrees.

[0070] In block 712, a first set of spectral components of the first beam of incident light is directed to a first portion of the substrate surface, and a second set of spectral components of the first beam is directed to a second portion of the substrate surface. In some embodiments, the first incident light signal is received by a collimator assembly 354 of the endpoint detection system 300 via a first output fiber. The achromatic lens 416 of the collimator assembly 354 can convert the first incident light signal into a first light beam containing multiple spectral components, each corresponding to a different wavelength of light. The achromatic lens 416 can direct the first set of spectral components (i.e., one or more first wavelengths of the first beam) to a first portion of the substrate surface, and the second set of spectral components (i.e., one or more second wavelengths of the second beam) to a first portion of the substrate surface. The first portion of the substrate surface may be substantially the same as (i.e., nearly equal to) the second portion of the substrate surface.

[0071] In block 714, a third set of spectral components of the second light beam of the incident light are directed to a third portion of the substrate surface, and a fourth set of spectral components of the second light beam are directed to a fourth portion of the substrate surface. In some embodiments, the second incident light signal is received by the collimator assembly 354 via a second output fiber of a second set of optical fibers. As described above, the achromatic lens 416 can convert the second incident light signal into a second light beam containing a plurality of spectral components, each corresponding to a different wavelength of light. The achromatic lens 416 can direct a third set of spectral components to a third portion of the substrate surface, and a fourth set of spectral components to a fourth portion of the substrate surface. In some embodiments, the third set of spectral components can be associated with one or more first wavelengths of the second light beam that correspond to a first wavelength of the first light beam. In other or similar embodiments, the third set of spectral components can be associated with one or more first wavelengths of the second light beam that are different from the first wavelength of the first light beam. In additional or alternative embodiments, the fourth set of spectral components can be associated with one or more second wavelengths of the second light beam, which may or may not correspond to the second wavelength of the first light beam. In some embodiments, the third portion of the substrate surface may be substantially the same as (i.e., nearly equal to) the fourth portion of the substrate surface.

[0072] In block 716, a first set of reflected spectral components, generated by a first set of spectral components directed to a first portion of the substrate surface, is received. A second set of reflected spectral components, generated by a second set of spectral components directed to a second portion of the substrate surface, is also received. As described with respect to Figures 4A-B, the collimator assembly can direct an incident light beam containing one or more spectral components to a target portion of the substrate surface at a certain angle of incidence. The incident light beam reflected from the target portion of the substrate surface is received by the achromatic lens 416 of the collimator assembly 354. Thus, the first set of spectral components directed to the first portion of the substrate surface (i.e., as the first incident light) is reflected from the first portion of the substrate surface as a first set of reflected spectral components. Additionally or alternatively, a second set of spectral components directed to the second portion of the substrate surface (i.e., as the second incident light beam) is reflected from the second portion of the substrate surface as a second set of reflected spectral components. The achromatic lens 416 receives the first and / or second set of reflection spectral components, as described above. In some embodiments, the first and / or second set of reflection spectral components are transmitted to the photodetector 366 of the optical component 362 via the first incident fiber of the first set of optical fibers in the optical fiber bundle 356 (i.e., as the first reflected light beam and / or the second reflected light beam) (as in the embodiments described above).

[0073] In block 718, a third set of reflected spectral components is received, generated by a third set of spectral components directed to a third portion of the substrate surface. A fourth set of reflected spectral components is also received, generated by a fourth set of spectral components directed to a fourth portion of the substrate surface. According to the embodiment described with respect to block 716, a third set of spectral components directed to a third portion of the substrate surface (i.e., as a third incident light beam) is reflected from the third portion of the substrate surface as a third set of reflected spectral components. Additionally or alternatively, a fourth set of spectral components directed to a fourth portion of the substrate surface (i.e., as a fourth incident light beam) is reflected from the fourth portion of the substrate surface as a fourth set of reflected spectral components. The achromatic lens 416 receives the third and / or fourth sets of reflected spectral components as described above. In some embodiments, a third and / or fourth set of reflection spectral components are transmitted to the photodetector 366 via the second incident fiber of the second set of optical fibers in the fiber bundle 356 (i.e., as the third and / or fourth reflected light beams), according to the embodiments described above.

[0074] In block 720, the reflectance of the substrate surface is determined based on at least one of a first and second set of reflection spectral components, or a third and fourth set of reflection spectral components. The photodetector 368 may receive the first and / or second set of reflection spectral components via a first incident fiber and receive the third and / or fourth set of reflection spectral components from a second incident optical fiber, according to the embodiments described above. In some embodiments, a processing device coupled to the photodetector 366 and / or optical component 362 (e.g., a processing device of the system controller 228) may determine the reflectance of one or more portions of the substrate surface (e.g., a first portion, a second portion, a third portion, or a fourth portion) based on the received set of reflection spectral components. The reflectance of one or more portions of the substrate surface may, as described above, form the basis for or be included in the spectral data generated for the substrate.

[0075] Figure 8 is a flowchart of Method 800, according to an aspect of the present disclosure, for training a machine learning model using spectral data collected by an endpoint detection system in multiple processing chambers. Method 800 can be executed by process logic that may include hardware (circuits, dedicated logic, etc.), software (running on a general-purpose computer system or dedicated machine, etc.), firmware, or a combination thereof. In one embodiment, Method 800 can be executed by a computer system such as the computer system architecture 100 of Figure 1. In other or similar implementations, one or more operations of Method 800 can be executed by one or more other machines not shown.

[0076] In block 810, the process logic can acquire a first metric indicating the reflectance of the surface of a first substrate during a first substrate process performed in a first processing chamber of the manufacturing system. In some embodiments, the reflectance of the surface of the first substrate can be included in spectral data collected with respect to the first substrate by a first endpoint detection system 300 during the first substrate processing. In block 812, the process logic can generate training data based on the first metric of the first processing chamber. In some embodiments, the training data may include a set of training inputs and target outputs. The process logic can generate a first training input based on the first metric for the first processing chamber, and the set of training inputs may include the first training input. In some embodiments, the process logic can acquire data related to one or more profile characteristics of the substrate after the substrate process and generate a first target output based on the acquired data. For example, the process logic can generate a first target output based on measurement values ​​generated on the first substrate after the first substrate process (i.e., by an in-line measurement device, integrated measurement device, external measurement device, etc.). The process logic can generate a mapping between a first training input and a first target output, and add the first target output to a set of target outputs in the training data. In additional or alternative embodiments, the process logic can generate the first training input and / or first target output based on other data associated with the first board (e.g., sensor data).

[0077] In block 814, the process logic can train a machine learning model to predict the endpoint of the substrate process using the generated training data. In some embodiments, the process logic can train a machine learning model to predict the endpoint of the substrate process by training the machine learning model to provide measurement values ​​of the substrate based on spectral data collected about the substrate during the substrate process. In block 816, the process logic can acquire a second metric indicating the reflectance of the surface of the second substrate during the second substrate process performed in the second processing chamber of the second manufacturing system. In some embodiments, the reflectance of the surface of the second substrate can be included in spectral data collected about the second substrate by the second endpoint detection system 300 during the second substrate process, according to the embodiments described above.

[0078] In some embodiments, the first manufacturing system and the second manufacturing system may be the same manufacturing system, such as manufacturing system 200. Therefore, the first processing chamber and the second processing chamber may be separate processing chambers of the same manufacturing system (e.g., processing chamber 214 and processing chamber 216). In other or similar embodiments, the first and second manufacturing systems may be the same manufacturing system, and the first processing chamber may be the same as the second processing chamber. In such embodiments, the first endpoint detection system may be the same as the second endpoint detection system. In yet another or similar embodiments, the first and second manufacturing systems may be different manufacturing systems. For example, the first manufacturing system may be manufacturing system 200, and the second manufacturing system may be separate from manufacturing system 200. In such embodiments, the processing devices of the second manufacturing system can be coupled to a prediction system 110 of the computer architecture 100 (e.g., via a network).

[0079] In block 818, the process logic can provide data associated with a second metric as input to a trained machine learning model. The process logic can obtain one or more outputs of the trained machine learning model. In some embodiments, one or more outputs may include a display of the measured value and a display of the confidence level associated with the measured value to the second substrate. In some embodiments, the process logic may determine that the measured value is associated with the second substrate in response to a determination that a confidence level criterion is met (e.g., the confidence level exceeds a confidence threshold level). In block 820, the process data may determine that an endpoint criterion associated with the second substrate process is met, based on one or more outputs of the trained machine learning model. In some embodiments, the process logic may determine that the endpoint criterion is met by determining that the measured value provided for the second substrate corresponds to a target measured value for the second substrate. The target measured value can be associated with the endpoint of the second substrate process. For example, the process logic may determine that the difference between the provided measured value and the target measured value associated with the endpoint of the substrate process is below a difference threshold. If the provided measurement corresponds to the target measurement, this can indicate that the end point of the second substrate process has been reached and the second substrate process is terminated.

[0080] In block 822, the process logic may terminate the second substrate process in the second chamber. In some embodiments, the process logic may terminate the substrate process in the second chamber in response to a determination that the endpoint criteria associated with the second substrate process have been met, according to block 820. The process logic may terminate the second substrate process by generating and transmitting a command to the processing device of the second processing chamber (e.g., a system controller such as system controller 228, or a local controller of the processing chamber) to terminate the second substrate process. In some embodiments, the process logic may continue the second substrate process in the second processing chamber in response to a determination that the endpoint criteria associated with the second substrate process have not been met (e.g., the provided measurement value does not correspond to the target measurement value). For example, the process logic may send a command to the processing device of the second processing chamber to continue the second substrate process, or it may not send a command to the processing device of the second processing chamber.

[0081] Figure 9 shows a graphical representation of an exemplary form of a computing device 900 capable of executing a set of instructions to cause the machine to perform one or more of the methods described herein. In alternative embodiments, the machine may be connected to other machines in a local area network (LAN), intranet, extranet, or the internet (e.g., a network connection). The machine may operate as a server or client machine in a client / server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The machine may be a personal computer (PC), tablet computer, set-top box (STB), personal digital assistant (PDA), mobile phone, web appliance, server, network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specifies the actions to be performed by that machine. Furthermore, although only a single machine is illustrated, the term “machine” is to be interpreted as including a collection of machines (e.g., computers) that individually or collectively execute one or more sets of instructions to perform one or more of the methods described herein. In the embodiment, the computing device 900 may correspond to one or more of the server machine 170, server machine 180, prediction server 112, or system controller 228, as described herein.

[0082] An exemplary computing device 900 includes a processing device 902, main memory 904 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM) such as synchronous DRAM (SDRAM), etc.), static memory 906 (e.g., flash memory, static random access memory (SRAM), etc.), and secondary memory (e.g., data storage device 928), which communicate with each other via a bus 908.

[0083] The processing device 902 can represent one or more general-purpose processors, such as microprocessors or central processing units. More specifically, the processing device 902 may be a composite instruction set computing (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, a processor that executes other instruction sets, or a processor that executes a combination of instruction sets. Alternatively, the processing device 902 may be one or more dedicated processing devices, such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), or network processors. Furthermore, the processing device 902 may be, or include, a system-on-a-chip (SoC), a programmable logic controller (PLC), or other types of processing devices. The processing device 902 is configured to execute processing logic for performing the operations and steps described herein.

[0084] Furthermore, the computing device 900 may include a network interface device 922 for communicating with the network 964. The computing device 900 may also include a video display unit 910 (e.g., a liquid crystal display (LCD) or cathode ray tube (CRT)), an alphanumeric input device 912 (e.g., a keyboard), a cursor control device 914 (e.g., a mouse), and a signal generator 920 (e.g., a speaker).

[0085] The data storage device 928 may include a machine-readable storage medium (or more specifically, a non-temporary computer-readable storage medium) 924 in which one or more instruction sets 926 embodying any one or more of the methods or functions described herein are stored. Here, a non-temporary storage medium refers to a storage medium other than a carrier wave. The instructions 926 may also reside in the main memory 904 and / or processing devices during execution by the computer device 900, the main memory 904, and the computer-readable storage medium, which constitute the device, in the processing devices 902.

[0086] Although the computer-readable storage medium 924 is shown as a single medium in exemplary embodiments, the term “computer-readable storage medium” means a single or multiple mediums (e.g., a centralized or distributed database, and / or associated caches and servers) that store one or more instruction sets. The term “computer-readable storage medium” is also construed to include any medium that can store or encode a set of instructions for execution by a machine, causing the machine to execute any of the methods of the present disclosure. Accordingly, the term “computer-readable storage medium” is construed to include, but is not limited to, solid-state memory, optical media and magnetic media.

[0087] The preceding description includes many specific details, such as examples of particular systems, components, and methods, in order to provide a full understanding of some embodiments of the Disclosure. However, it will be apparent to those skilled in the art that at least some embodiments of the Disclosure can be implemented without these specific details. In other examples, well-known components or methods are not described in detail or are presented in simple block diagram form to avoid unnecessarily obscuring the Disclosure. Accordingly, the specific details described are merely illustrative. Specific implementations may differ from these illustrative details but are still considered to be within the scope of the Disclosure.

[0088] Throughout this specification, any reference to “one embodiment” or “embodiment” means that a particular feature, structure, or characteristic described in relation to an embodiment is included in at least one embodiment. Therefore, the phrases “in one embodiment” or “in an embodiment” appearing in various places throughout this specification do not necessarily all refer to the same embodiment. Furthermore, the term “or” is intended to mean inclusive, not exclusive. Where the terms “about” or “approximately” are used herein, this is intended to mean that the nominal value presented is accurate to within ±10%.

[0089] Although the operations of the methods described herein are shown and described in a specific order, the order of the operations of each method can be changed, certain operations can be performed in reverse order, and certain operations can be performed, at least partially, in parallel with other operations. In another embodiment, the instructions or sub-operations of separate operations can be performed intermittently and / or alternately.

[0090] The above description is for illustrative purposes only and should not be understood as limiting. Many other embodiments will become apparent to those skilled in the art upon reading and understanding the above description. Accordingly, the scope of this disclosure should be determined by reference to the appended claims and the entire scope of equivalents to which such claims are entitled.

Claims

[Claim 1] A destination detection system, A light source component configured to generate incident light, A light bundle coupled to a light source, A first set of optical fibers including a first output optical fiber and a first input optical fiber, wherein the first output optical fiber is arranged at a pair angle with respect to the first input optical fiber, A second set of optical fibers comprising a second output optical fiber and a second input optical fiber, wherein the second output optical fiber comprises a second set of optical fibers arranged at a pair angle with respect to the second input optical fiber, The first and second output optical fibers are configured to receive incident light from a light source, forming an optical bundle. A collimator assembly coupled to an optical bundle, wherein the collimator assembly comprises an achromatic lens, and the achromatic lens is In response to the reception of a first light beam of incident light from a first output optical fiber, a first plurality of spectral components of the first light beam are directed to a first portion of the substrate surface, and a second plurality of spectral components of the first light beam are directed to a second portion of the substrate surface, the first portion being substantially the same as the second portion. A first set of multiple reflection spectral components of light and a second set of multiple reflection spectral components of light are collected from the substrate surface. The first set of multiple reflection spectral components of light are generated by the first set of multiple spectral components directed towards a first portion of the substrate surface, and the second set of multiple reflection spectral components of light are generated by the second set of multiple spectral components directed towards a second portion of the substrate surface. A color-shifting lens that transmits a first plurality of reflection spectral components and a second plurality of reflection spectral components to the first incident optical fiber of the optical bundle, A photodetector component coupled to an optical bundle, configured to receive a first plurality of reflection spectral components and a second plurality of reflection spectral components from a first incident optical fiber, An endpoint detection system comprising a processing device communicatively coupled to a photodetection component, the processing device configured to determine the reflectance of a substrate surface based on a first plurality of reflectance spectral components and a second plurality of reflectance spectral components.

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