System and method for evaluating substrate, such as mask or photomask, treated by optical microlithography

Abstract

An evaluation system for evaluating a substrate is provided. The evaluation system includes at least one optical device configured to have a focus at a target location of the substrate, an image capture device configured to capture an image of the target location of the substrate via the at least one optical device, an illumination unit configured to illuminate a target position of the substrate via the at least one optical device, and a control unit configured to perform an imaging sequence. The imaging sequence comprises an image trigger signal and an illumination trigger signal, wherein the control unit is configured to send the image trigger signal to the image capture device and to send the illumination trigger signal to the illumination unit. The image capture device is configured to receive an image trigger signal and capture an image based on the image trigger signal. The irradiation unit is configured to receive the irradiation trigger signal and irradiate the substrate based on the irradiation trigger signal.

Description

Technical Field

[0001] This invention generally relates to the field of optical microlithography. In particular, this invention relates to an evaluation system used in evaluating substrates processed by optical microlithography. Background Technology

[0002] Today, the demand for and production of electronic components continues to increase. One of the most common methods for efficiently and accurately manufacturing electrical components such as semiconductors and displays is optical microlithography, in which a beam of light transfers a pattern from a photomask substrate onto a coated wafer to create, for example, a display wafer. Optical microlithography can produce extremely small patterns, down to the nanometer scale, and provides precise control over the pattern design. Due to the orders of magnitude of size and the required precision of the printed patterns in these parts, the accuracy of the photomask substrate is critical. Furthermore, the precision of the printed pattern, and consequently the precision of the photomask substrate, determines the performance of the manufactured electronic components.

[0003] In the production of photomask substrates (which are also a type of patterned substrate), errors can occur due to insufficient calibration or disturbances such as vibration or thermal instability. Errors or defects in the photomask substrate can lead to manufacturing errors in electronic components and directly affect their performance, functionality, and reliability. This can result in increased costs and production losses.

[0004] Early detection of errors or defects in patterned substrates (such as photomask substrates) can reduce costs and ensure the performance of manufactured electronic components. Furthermore, evaluating patterned substrates allows for the calibration of the patterned substrate manufacturing process. To ensure substrate accuracy, a high-resolution and reliable method for evaluating substrates is needed. Summary of the Invention

[0005] The object of this invention is to provide an improved technique for evaluating substrates. This and other objects are achieved by an evaluation system having the features of the independent claims and a method for evaluation. Preferred embodiments are defined in the dependent claims.

[0006] In a first aspect of the present invention, an evaluation system for evaluating a substrate is provided. The evaluation system includes: at least one optical device configured to have a focal point at a target location on the substrate; an image capturing device configured to capture at least one image of the target location on the substrate via the at least one optical device; an illumination unit configured to illuminate the target location on the substrate via the at least one optical device; and a control unit configured to execute an imaging sequence, wherein the imaging sequence includes at least one image trigger signal and at least one illumination trigger signal. The control unit is configured to send at least one image trigger signal to the image capturing device and at least one illumination trigger signal to the illumination unit. The image capturing device is configured to receive the at least one image trigger signal and capture at least one image based on the at least one image trigger signal. The illumination unit is configured to receive the at least one illumination trigger signal and illuminate the substrate based on the at least one illumination trigger signal.

[0007] The substrate may include a flat surface, sheet, and / or plate. For example, the substrate may include a plate / sheet. The substrate may contain a compound silica-based material, such as glass, quartz, or soda-lime glass. The substrate may be partially transparent. The substrate may contain at least one coating or layer. The substrate may include at least one patterned coating or layer. The surface of the substrate may be provided with a coating or printed pattern. The substrate may be a mask or photomask. The substrate may be arranged / placed in the XY plane, i.e., a two-dimensional plane extending in the X and Y directions. The substrate may be arranged / placed on a movable or static platform / stage in the XY plane. The substrate may be arranged on / attached to a movable or static holder / attachment unit in the XY plane. The platform, stage, holder, and / or attachment unit may be transparent or opaque. The platform, stage, holder, and / or attachment may include an opening through which light can travel to illuminate the substrate.

[0008] The at least one optical device is configured to have a focal point at a target location on the substrate. The target location may be the location of the substrate. The target location may be defined by XY coordinates in the XY plane. The target location may be the location of the substrate to be evaluated. The at least one optical device may be configured to allow an image capture device to capture an image at the target location. It should be understood that the at least one optical device may be configured to allow the evaluation system to capture images around / near / near the target location. For example, the at least one optical device may be configured to guide / transmit / modulate light originating from and around the target location to reach the image capture device. The at least one optical device may be configured to optimize image capture and / or illumination at a very small target location / feature (e.g., in the micrometer or nanometer range). The at least one optical device may include one or more optical elements / components / parts. The one or more optical elements may be lenses, filters, windows, optical planes, prisms, polarizers, beam splitters, waveplates, optical fibers, and / or mirrors. The at least one optical device may be arranged between the substrate and at least one of the image capture device and the illumination unit. The at least one optical device may include an illumination portion and an imaging portion. At least one optical device may have an illumination portion arranged to have an illumination optical path for guiding / transmitting illumination light from the illumination unit to a target location. At least one optical device may have an imaging portion arranged to have an imaging optical path for guiding light from the target location to an image capture device, such as scattered / reflected / transmitted light from the illumination. The illumination and imaging optical paths may be at least partially integrated; that is, at least a portion of the at least one optical device is used for both illumination and image capture. In the example, the evaluation system may include a first optical device and a second optical device. The first optical device may include an illumination portion, and the second optical device may include an imaging portion. The illumination and imaging optical paths may then be separated.

[0009] An image capturing device is configured to capture at least one image. The image capturing device is configured to capture at least one image of a target location on a substrate via the at least one optical device. The phrase "via at least one optical device" here means capturing at least one image of the target location through at least one optical device, i.e., facilitating image capture through at least one optical device. The image capturing device can be configured to capture at least one image of the target location on the substrate through an imaging portion of the at least one optical device. The image capturing device can capture the image of the target location on the substrate via an imaging optical path. The image capturing device can be, for example, any image sensor or camera. The image capturing device and the at least one optical device can together form an image capturing system. The image capturing system can have resolution in the micrometer and / or nanometer range, i.e., capturing / distinguishing features at the micrometer and / or nanometer scale.

[0010] The illumination unit can be configured to emit light. The illumination unit can be configured to emit monochromatic or coherent light. The illumination unit is configured to illuminate a target location on the substrate via at least one optical device. By using the phrase "via at least one optical device," it means that the illumination / emitted light is guided / directed to the target location via at least one optical device, i.e., illumination is facilitated by at least one optical device. The illumination unit can be configured to illuminate the target location on the substrate via an illumination portion of at least one optical device. Light from the illumination unit can follow an illumination optical path such that light is transmitted to illuminate the target location on the substrate. The illumination unit and at least one optical device can together form an illumination system. The illumination system can be configured to irradiate micron and / or nanometer-scale features.

[0011] The control unit is configured to execute an imaging sequence. The imaging sequence can be, for example, a sequence / series of events / movements that follow each other in a specific order. An event can be the transmission of an image trigger signal or an illumination trigger signal. Movement can be the movement of a part of the evaluation system (e.g., at least one optical device) or the movement of the substrate. The imaging sequence includes at least one image trigger signal and at least one illumination trigger signal. The at least one image trigger signal can command / provide instructions / trigger an image capture device to capture one or more images of a target location. For example, upon receiving an image trigger signal, an image is captured for the first time (i.e., during a first time window). The at least one illumination trigger signal can command / provide instructions / trigger an illumination unit to illuminate the target location. For example, upon receiving an illumination trigger signal, a second illumination is performed, i.e., during a second time window. The image sequence can include a single image trigger signal or a series of multiple image trigger signals. The image sequence can include a single illumination trigger signal or a series of multiple illumination trigger signals. Depending on the type of substrate evaluation, the imaging sequence can include different numbers of image trigger signals and illumination trigger signals. The control unit is configured to send at least one image trigger signal to the image capture device. The image capture device is configured to receive the at least one image trigger signal and capture an image of a target location on the substrate based on the at least one image trigger signal. The control unit is configured to send at least one illumination trigger signal to the illumination unit. The illumination unit is configured to receive the at least one image trigger signal and illuminate the target location on the substrate based on the illumination trigger signal.

[0012] The control unit can be connected to the image capture device and the lighting unit using, for example, cable and / or wireless alternatives. The control unit and the image capture device can be connected such that the control unit can send at least one image trigger signal to the image capture device and receive at least one image captured by the image capture device. The control unit and the lighting unit can be connected such that the control unit can send at least one lighting trigger signal to the lighting unit. The control unit may include analog and / or digital processing circuitry. The control unit may include a processing unit / computer.

[0013] The evaluation system for evaluating a substrate according to the first aspect of the invention is advantageous because it provides coordinated image capture and substrate illumination for generating data usable for evaluating the substrate. The invention allows for the evaluation of the substrate by at least one of light reflection and light transmission analysis. The evaluation system illuminates the substrate and can detect reflected and / or transmitted light via an image capture device to evaluate the substrate. Furthermore, the invention provides improved control over illumination and image capture at target locations on the substrate. Imaging sequences can be customized, and therefore the evaluation system can be adapted to different types of evaluation. The evaluation system provides improved evaluation of the substrate, particularly for substrates at the micrometer and / or nanometer scale.

[0014] According to embodiments of the present invention, at least one optical device may include an objective lens. An evaluation system may include at least one position sensor configured to generate position data indicating the position of the objective lens relative to a substrate. A control unit may be configured to receive position data from the at least one position sensor and to perform an imaging sequence based on the position data. It should be understood that the imaging sequence may be based in part on the position data, but not exclusively on the position data. The objective lens may be the optical element arranged closest to the substrate in the at least one optical device. The objective lens may be arranged adjacent to the substrate. The objective lens may include a final lens or a field lens, these types of which can be found in a mask writer. The objective lens may be configured to focus and / or collect light at / from a target location on the substrate. At least one position sensor may be configured to generate position data indicating the position of the objective lens relative to the substrate. At least one position sensor may be configured to generate position data indicating the position of the substrate and / or the position of a platform / holder on which the substrate may be arranged / placed. The position data may indicate a first position of the objective lens and / or a second position of the substrate, and / or a platform / holder on / where the substrate is arranged. Position data may include a position defined in a plane, such as X and Y coordinates in an XY plane. The control unit may be connected to at least one position sensor, for example, via cable or a wireless alternative. The control unit may receive position data from at least one position sensor. The control unit may be configured to perform an imaging sequence based on the position data. If the position data indicates the position of the objective lens relative to the substrate corresponding to the target location to be evaluated, the control unit may be configured to perform an imaging sequence at that location. If the position data indicates the position of the substrate corresponding to the target location to be evaluated or the position of the platform / holder where the substrate is arranged / placed, the control unit may be configured to perform an imaging sequence at that location. In embodiments, the position data includes references to at least one image, such that the position data can be associated with at least one image.

[0015] Image capture can be combined with location data, allowing the image capture to be synchronized / associated / linked with the location data. For example, images can be captured / taken, and location data can be recorded at a point during the image capture and / or at the end of the image capture process. The location data can be associated with the simultaneously captured images. An advantage of this embodiment is that it further improves evaluation performance. Furthermore, this allows for the customization of imaging sequences for specific locations on the substrate (e.g., target locations), providing improved performance and accuracy of the evaluation system. In other words, the evaluation system (e.g., a control unit) can be configured to perform an imaging sequence and / or send at least one image trigger signal and / or at least one illumination trigger signal based on location data. In one embodiment, the control unit is configured to compare the location data with a predetermined set of locations to determine when to perform an imaging sequence and / or send at least one image trigger signal and / or at least one illumination trigger signal.

[0016] According to embodiments of the present invention, at least one position sensor may include at least one of an interferometer and an encoder. The interferometer may be any device for extracting information from interference, here for determining / measuring the relative displacement and / or absolute distance of one or more objects. The interferometer may be configured to determine / measuring distances in different directions, e.g., distances in the X and Y directions of the XY plane. The interferometer may be configured to determine / measuring the position of an objective lens relative to a substrate and / or the position of the objective lens and / or the position of the substrate. The encoder may be any device configured to generate position data based on at least one mechanical indication. For example, the encoder may include a device configured to measure mechanical positions (such as distance from the origin). In a preferred embodiment, at least one position sensor includes both an interferometer and an encoder.

[0017] Using an interferometer and / or an encoder as at least one position sensor provides improved precision and accuracy in determining the position of objects such as objectives and / or substrates. By extension, the improved accuracy of position determination leads to improved accuracy in the evaluation system.

[0018] According to embodiments of the present invention, a control unit can be configured to run a timer. The control unit can be configured to send at least one of an image trigger signal and at least one illumination trigger signal based on the timer being triggered. The timer can be a high-resolution timer. The timer can be a clock. The timer can be configured to count at fixed time intervals. The timer can be configured to generate pulses at regular time intervals. The timer can be configured to control a sequence of events or to repeat or initiate events at expected time points or time intervals. An imaging sequence can be based on the timer. At least one image trigger signal in the imaging sequence can be based on the timer. At least one illumination trigger signal in the imaging sequence can be based on the timer. A series or a set of image trigger signals and illumination trigger signals can be based on the timer, such that the trigger signals are scheduled / arranged / organized / sent at different expected time points and / or time intervals. The control unit can be configured to run the timer and thereby perform the imaging sequence based on the timer. The control unit can be configured to send at least one image trigger signal at predetermined time points or time intervals based on the timer. The timer can be included in the control unit. The control unit can be configured to send at least one illumination trigger signal at predetermined time points or time intervals. The control unit can be configured to send a series or a set of image trigger signals and illumination trigger signals at different expected time points or time intervals.

[0019] Imaging sequences can be executed based on a timer, allowing image capture and illumination to be performed on a time-based basis. The timer and the position on the substrate can be synchronized. The actual position on the substrate can be combined with an image captured at a predetermined position. A certain time or time interval can thus provide an evaluation of the accuracy of system improvements.

[0020] In the example, an image can be captured at a specific time set by a timer, and illumination can be performed at the same specific time set by the timer, with synchronization between image capture and illumination to improve image quality. It should be understood that an image can be captured during a specific time interval; that is, a specific time can also mean a specific time interval. Furthermore, positional data indicating the position of the objective lens and / or substrate can be synchronized with at least one of the image capture device and illumination unit, enabling the evaluation system to generate an image improved by synchronized illumination and to generate positional data associated with the image. Therefore, the evaluation system can generate images of one or more target locations, and positional data indicating the position of at least one of the objective lens and substrate, or indirectly via a platform / holder on which / where the substrate is disposed, where image capture, illumination, and positional data are, for example, temporally related / associative / linked.

[0021] According to an embodiment of the present invention, the control unit can be configured to receive a position sequence including a set of target positions, wherein a timer can be based on the position sequence.

[0022] The position sequence may include at least one target position on the substrate. The position sequence may include a set of target positions on the substrate, where the target positions correspond to positions on the substrate to be evaluated. The position sequence may include a set of target positions, where the target positions are XY coordinates in the XY plane where the substrate can be arranged / placed. The control unit may be configured to receive the position sequence via user input and / or may pre-store the position sequence. The control unit may be configured to run a timer based on the position sequence. In other words, the control unit may be configured to start a timer at certain positions. For example, if position data indicates a target position in the position sequence, the control unit may be configured to run a timer to perform imaging and determine a sequence based on the timer. That is, the control unit may be configured to send at least one image trigger signal and / or at least one illumination trigger signal based on the timer, where the timer can be started by reaching a position in the position sequence. The evaluation system may be configured to move the substrate and / or at least one optical device. By moving between target positions in the position sequence, the control unit can run a timer at each target position in the position sequence. Thus, an imaging sequence can be performed at each target position in the position sequence.

[0023] This provides improved control and synchronization of image capture and illumination with substrate positioning. Furthermore, it enables / provides / allows the evaluation of multiple target locations on the substrate by performing customized imaging sequences at each target location. By sequentially controlling the image capture device and illumination unit using a sequence list (such as a combination of position order and synchronization of image capture, illumination, and position data), rapid coarse measurements can be created using a position-based sequence list and a moving platform / stage / holder on which / the substrate is arranged. This sequence will then be a row or column of markers, each with position and image trigger signals and illumination trigger signals, and the entire row or column will have a servo log. Position-based sequences can also be associated with inspection tools equipped with line scan cameras.

[0024] According to embodiments of the present invention, at least one image trigger signal may include an image window signal, and at least one illumination trigger signal may include an illumination window signal. When the term "window signal" is used, it refers hereinafter to both the image window signal and the illumination window signal. The window signal may be defined over a time interval. The window signal may be considered to have a zero value outside its defined time interval. The image window signal may be defined as a time interval for capturing an image of a target location on a substrate. The illumination window signal may be defined as a time interval for illuminating a target location on a substrate. For example, a first image trigger signal may span a first time interval, and a first illumination trigger signal may span a second time interval, wherein the image capture device is configured to capture an image within the first time interval upon receiving the first image trigger signal, and the illumination unit is configured to illuminate during the second time interval upon receiving the first illumination trigger signal.

[0025] The advantage of this embodiment is that images can be captured during intervals rather than at a single point in time, in order to generate images that can capture changes, such as movement of the substrate and therefore movement of features in the image. For example, the substrate may move back and forth in one or more directions, i.e., rock. This can be captured using a window signal, which can capture, for example, one or more cycles of movement. In other words, an image can be captured / generated as an average value of the target position / substrate during the time interval. This embodiment also provides an evaluation system that provides illumination during the time interval by sending an illumination window signal. This can further improve the quality of substrate evaluation because it can provide stable illumination during the time interval. A combination of a window image trigger signal and a window illumination trigger signal is particularly advantageous.

[0026] According to embodiments of the present invention, the image window signal and the illumination window signal may at least partially overlap in time. Therefore, the image capture device may be configured to capture at least one image within a first time interval defined by the image window signal, and the illumination unit may be configured to illuminate within a second time interval defined by the illumination window signal. Furthermore, the image capture device may be configured to capture an image during a time interval at least partially the same as the time interval during which the illumination unit is configured to illuminate. The image window signal may completely overlap with the illumination window signal in time, meaning that the time interval defining the image window signal may be entirely included within the time interval defining the illumination window signal. Wherein the illumination window signal is defined, the illumination window signal may completely overlap with the image window signal in time, meaning that the time interval defining the illumination window signal may be entirely included within the time interval defining the image window signal. The image window signal may partially overlap with the illumination window signal in time. Then, the time interval defining the image window signal may partially overlap with the time interval defining the illumination signal.

[0027] The advantage of this embodiment is that image capture and illumination occur at least partially during the same time period. This can improve image properties, for example, by increasing contrast, which in turn allows for improved evaluation. Furthermore, different combinations of illumination and image capture can be performed depending on the type of evaluation. The target location on the substrate can be illuminated throughout the entire image capture period, i.e., the illumination window signal completely overlaps with the image window signal. Alternatively, the target location on the substrate can be illuminated during a portion of the image capture period, i.e., the illumination window signal partially overlaps with the image window signal. Thus, the imaging sequence can be advantageously tailored to provide the desired type of evaluation.

[0028] According to an embodiment of the present invention, the lighting unit may include a laser.

[0029] According to embodiments of the present invention, the evaluation system may include at least one secondary sensor. A control unit may be configured to receive sensor data from the at least one secondary sensor. The at least one secondary sensor may include at least one of a pneumatic sensor, an optical sensor, an inductive sensor, an accelerometer, and a temperature sensor. At least one auxiliary sensor may be configured to generate sensor data. The at least one secondary sensor may be connected to / arranged on at least one of an optical device, an image capture device, an illumination unit, a position sensor, and a platform / holder on which a substrate may be arranged / placed. For example, the secondary sensor may be arranged on at least one optical device and configured to measure the temperature at at least one optical device / objective and / or the temperature of at least one optical device / objective, or the position of the objective. The pneumatic sensor may be a mass sensor, a volume sensor, or a flow rate sensor. The pneumatic sensor may, for example, be configured to measure the flow rate of a gas. The inductive sensor may, for example, be configured to measure the position of an object. The accelerometer may, for example, be configured to detect and / or measure mechanical disturbances. The temperature sensor may, for example, be configured to measure and / or detect thermal disturbances or thermal changes. The control unit can be connected to at least one of the pneumatic sensor, optical sensor, inductive sensor, accelerometer, and temperature sensor using, for example, cable and / or wireless alternatives. In the example, the sensor data may include a first reference to at least one image. Furthermore, the sensor data may include a second reference to position data associated with at least one image generated by at least one position sensor. In other words, the sensor data may include a reference to at least one of the position data and at least one image.

[0030] The advantage of this embodiment is that the evaluation system provides sensor data that can be associated with at least one image in order to provide an evaluation of improvements to the substrate. In other words, the evaluation system can provide an evaluation based on a combination of information from at least one image and at least one secondary sensor.

[0031] According to embodiments of the present invention, the evaluation system may include a data storage device for storing evaluation data. The evaluation data may include at least one of location data, sensor data, at least one captured image, and log data of at least one image trigger signal and at least one illumination trigger signal. The data storage device may be a computer-readable storage medium. The stored evaluation data can be used to perform post-processing and analysis of the data.

[0032] This enables traceable, high-resolution recording, for example, in real-time of location data, sensor data, at least one captured image, and log data of at least one image trigger signal and at least one illumination trigger signal. Therefore, the at least one image, the location data, and the sensor data can be stored in real-time, for example, by creating a data log of correlated data using references between different datasets. By storing the evaluation data, post-processing of the evaluation data can be performed, and more sophisticated methods for determining where to capture at least one image can be implemented. Furthermore, this embodiment has the advantage that the data can be processed after the imaging sequence is completed, allowing for further processing to improve the evaluation of the substrate.

[0033] According to embodiments of the present invention, an evaluation system can be configured to determine at least one of parameters and conditions of a substrate based on evaluation data. A control unit can be configured to determine the parameters and / or conditions. The evaluation system may include a second control unit configured to determine the parameters and / or conditions. The determined parameters and / or conditions of the substrate may indicate the quality of the substrate or the precision of its manufacturing. The parameters may be any measure describing the substrate or at least a portion of the substrate, such as the size and / or shape of the substrate. The conditions may be an indication of the overall condition / state of the substrate. The conditions may be at least partially based on the parameters.

[0034] The advantage of this embodiment is that the evaluation system provides information about the quality of the substrate and / or any defects and / or any inaccuracies. This allows for improved evaluation of the substrate.

[0035] According to embodiments of the present invention, an evaluation system can be configured to generate at least one processed image based on at least one of evaluation data, parameters, and conditions. The processed image may be a processed version of at least one image, for example, to improve a captured image and / or enhance certain characteristics in the captured image. A control unit can be configured to generate at least one processed image based on at least one of evaluation data, parameters, and conditions. In an embodiment, the evaluation system includes a second control unit configured to generate at least one processed image based on at least one of the evaluation data, the parameters, and the conditions. The second control unit may be located external to the rest of the evaluation system, for example, in a computer used for post-processing.

[0036] The advantage of this embodiment is that the evaluation system can provide processed images that allow for improved evaluation of the substrate.

[0037] According to embodiments of the present invention, the evaluation system can be configured to compare evaluation data with predetermined data and generate comparison data, and determine at least one of the parameters and conditions of the substrate based on the comparison data. The predetermined data may be reference data related to the substrate being evaluated. The predetermined data may, for example, include data indicating the acceptable accuracy of the substrate being evaluated.

[0038] The advantage of this embodiment is that the evaluation system can provide an improved and / or more accurate assessment of the substrate. By comparing the evaluation data with predetermined data, the detectability of variations / defects can be increased, and changes over time can also be observed.

[0039] According to an embodiment of the present invention, the at least one optical device may include: a first optical device disposed on a first side of the substrate, wherein the image acquisition device may be configured to acquire at least one image of the target location of the substrate via the first optical device; and a second optical device disposed on a second side of the substrate, wherein the illumination unit may be configured to illuminate the target location of the substrate via the second optical device. The second side may be opposite to the first side. The substrate may be disposed / placed in the XY plane. The first side of the substrate may be a first side / space / position relative to the XY plane. The second side of the substrate may be a second side / space / position relative to the XY plane, opposite to the first side / space / position. Therefore, the first optical device and the second optical device may be disposed on opposite sides of the substrate / XY plane. The substrate may be disposed in a holder such that the substrate is accessible / reachable from both the first side and the second side, for example, with respect to light. The first optical device may be disposed between the substrate and the image acquisition device. The second optical device may be disposed between the substrate and the illumination unit. The first optical device may include an objective lens / final lens and / or a field lens. The second optical device may include an objective lens / final lens and / or a field lens. The first and second optical devices may include different types of objective lenses. In an example, the first optical device may include an objective / final lens, and the second optical device may include a field lens. Preferably, the first side of the substrate may be the side of the substrate having / with the layer / coating to be evaluated and / or a patterned layer / coating. The first optical device may include an imaging section arranged to have an imaging optical path for guiding light (e.g., light from an illumination unit) from a target location on the substrate to an image capturing device. The first and / or second optical devices may include an illumination section arranged to have an illumination optical path for guiding / transmitting illumination light from the illumination unit to a target location on the substrate. Light from the illumination unit may be transmitted / provided to the target location on the substrate from a second side via the second optical device and / or from a first side via the first optical device.

[0040] Thus, light from the illumination unit can be provided to the target location on / from one side of the substrate, and at least one image of the target location can be captured on / from the other side of the substrate. Light can be at least partially transmitted through the substrate, for example, in the light-transmitting portion of the patterned substrate.

[0041] This embodiment enables the performance of transmission measurements for evaluating a substrate and / or a combination of transmission measurements and reflection measurements for evaluating the substrate. First and second optical devices arranged on opposite sides of the substrate can provide improved contrast in at least one captured image. Furthermore, by being able to perform both transmission and reflection measurements, improved versatility and flexibility in substrate evaluation can be provided. For example, using both transmission and reflection measurements makes it easier to distinguish any defects and / or inaccuracies in the substrate from particles and / or dirt that may contaminate the substrate.

[0042] In an exemplary embodiment of the present invention, an apparatus for evaluating a substrate is provided. The apparatus may include an evaluation system according to embodiments of the present invention, and a platform and / or holder, wherein a substrate is disposed on the platform and / or holder, and wherein at least one position sensor is configured to generate position data indicating the position of an objective lens relative to at least one of the substrate and the platform. The platform may be configured to receive the substrate to be evaluated. The substrate may be disposed directly on the platform. The substrate may be disposed indirectly on the platform, for example, on an air cushion. The platform may be configured to move relative to at least one optical element and / or image capture device of the evaluation system. At least one optical element and / or image capture device of the evaluation system may be configured to move relative to the platform, thereby moving relative to the substrate disposed on the platform.

[0043] In a second aspect of the invention, a method for evaluating a substrate using an evaluation system is provided, the evaluation system including at least one optical device, an image capture device, an illumination unit, and a control unit. The method includes executing an imaging sequence, the imaging sequence including the steps of: sending at least one image trigger signal from the control unit to the image capture device; and sending at least one illumination trigger signal from the control unit to the illumination unit. The method further includes: capturing an image of a target location of the substrate by the image capture device based on the at least one image trigger signal via the at least one optical device, and illuminating the target location of the substrate by the illumination unit based on the at least one illumination trigger signal via the at least one optical device.

[0044] Other objects, features, and advantages of the invention will become apparent upon studying the following detailed disclosure, drawings, and appended claims. Those skilled in the art will recognize that, even though the different features of the invention are recited in different claims, they can be combined in embodiments other than those described below. Attached Figure Description

[0045] This and other aspects of the invention will now be described in more detail with reference to the accompanying drawings, which illustrate embodiments of the invention.

[0046] Figure 1A-1C An example of a substrate to be evaluated is shown schematically.

[0047] Figure 2 An evaluation system for evaluating a substrate according to a first aspect of the present invention is illustrated schematically.

[0048] Figure 3 An apparatus and system for evaluating a substrate are schematically illustrated according to some embodiments of the present invention.

[0049] Figure 4 An apparatus and system for evaluating a substrate are schematically illustrated according to some embodiments of the present invention.

[0050] Figure 5 An evaluation system for evaluating a substrate is illustrated schematically according to some embodiments of the present invention.

[0051] Figures 6A-6F An example of an imaging sequence is illustrated schematically.

[0052] Figure 7 The diagram schematically illustrates example operations according to some embodiments of the present invention.

[0053] Figure 8 A method for evaluating a substrate according to a second aspect of the present invention is illustrated schematically. Detailed Implementation

[0054] refer to Figure 1A-1C A schematic diagram of an example of substrate 110 is shown. Figure 1A-1B An exemplary substrate is schematically shown in cross-section in the figure, and... Figure 1C An exemplary substrate is schematically shown from above. Figure 1A-1C In this structure, substrate 110 includes plate 114 and first layer 115. The plate can be a flat sheet. The first layer 115 can be patterned, such as... Figure 1A-1C As shown. The first layer 115 is disposed on the surface of the plate 114. Figure 1A In this process, the substrate also includes a second layer 116. The second layer 116 can be patterned, i.e., includes patterns, such as... Figure 1A As shown. The second layer 116 is disposed on the first layer 115, for example, on the surface of the first layer 115. Figure 1B The substrate also includes a third layer 117. The third layer 117 is disposed on the first layer 115, and may also be disposed on the plate 114. The substrate 110 may consist only of the plate 114 and the first layer 115. It should be understood that different layers may completely or at least partially cover / enclose the surface of at least one of the first plate 110, the first layer 115, and the second layer 116.

[0055] Plate 114 may include a rigid and / or temperature-stable material. Plate 114 may include a light-transmitting material, i.e., transparent. Plate 114 may include a material based on the chemical compound silicon dioxide, such as glass, quartz, or soda-lime glass. First layer 115 may include an opaque material. First layer 115 may include a metal-based material, such as chromium. Second layer 116 may include a photoresist. Third layer 117 may include a surface film. Third layer 117 may be a thin film that partially or completely covers first layer 115 and / or plate 114. Third layer 117 may include a light-transmitting material, i.e., transparent. Third layer 117 may be configured to prevent substrate 110 from being contaminated. In other words, third layer 117 may include a protective surface configured to protect at least one of plate 114, first layer 115, and second layer 116. In one example, substrate 110 may include a glass plate 114 (i.e., plate 114 may be a glass plate) and an opaque patterned chromium layer 115. Substrate 110 may be a photomask.

[0056] exist Figure 1C The example substrate is shown from above and is arranged in the XY plane. The XY plane has an X direction and a Y direction that are orthogonal to each other.

[0057] exist Figure 1C In the figure, the substrate includes a plate 114 and a first layer 115. In the figure, plate 114 is shown as a white area, and the first layer 115 is shown as a gray area. Plate 114 may be translucent, and the first layer 115 may represent an opaque area. Figure 1C The target position 112 on the substrate 110 is shown in the figure. The target position 112 can be defined by the XY coordinates in the XY plane.

[0058] In one example, the evaluation system according to the invention can evaluate substrate 110 by measuring the placement or marking of a pattern on substrate 110. A first layer 115 and / or a second layer 116 can form the pattern of substrate 110. In other words, the evaluation system can be configured to determine the pattern of the substrate, such as a pattern formed by the first layer 115 and / or the second layer 116, wherein the first layer 115 and / or the second layer 116 are arranged on board 114. Determining the pattern can mean determining the shape and / or size of at least a portion of the substrate (e.g., the first layer 115 and / or the second layer). Determining the shape and / or size can include measurements determining the distance and / or length of one or more features of the substrate. The pattern can be a predetermined pattern. Therefore, the evaluation system can be configured to detect defects in the pattern by comparing it with a predetermined pattern (i.e., a desired pattern). A control unit (not shown) can be configured to determine the pattern. A predetermined set of target locations can be selected for evaluation, thereby evaluating the pattern at different locations on substrate 110.

[0059] In one example, substrate 110 can be inspected / evaluated by examining / assessing defects or contamination. For example, substrate 110 including the third layer 117 can be inspected by checking whether the surface of layer 117 is contaminated (e.g., contaminated with particles). A predetermined set of target locations can be selected for inspection, thereby allowing inspection to be performed at different locations on substrate 110.

[0060] refer to Figure 2 The diagram illustrates an evaluation system 100 for evaluating a substrate 110 according to a first aspect of the invention. The evaluation system 100 includes an optical device 120. The optical device 120 is configured to have a focal point at a target location 112 on the substrate 110. The evaluation system 100 includes an image capturing device 130. The image capturing device 130 is configured to capture at least one image of the target location 112 on the substrate 110 via the optical device 120, meaning that at least one image of the target location 112 is captured by the optical device 120. The evaluation system 100 includes an illumination unit 140. The illumination unit 140 is configured to illuminate the target location 112 on the substrate 110 via the optical device 120, meaning that the illumination is directed to the target location 112 by the optical device 120. The optical device 120 is arranged in the optical path between the substrate 110, the image acquisition device 130, and the illumination unit 140. That is, photons emitted from the substrate 110 pass through the optical device 120 before reaching the image acquisition device 130, and photons emitted from the illumination unit 140 pass through the optical device 120 before reaching the substrate 110.

[0061] exist Figure 2 In the diagram, dashed lines and arrows indicate the optical paths used for illumination and image capture. (Example:) Figure 2 As shown, illumination (e.g., emitted light) from illumination unit 140 is guided / transmitted to a target position 112 on substrate 110 via optical device 120. Optical device 120 may include an illumination section having an illumination optical path for guiding / transmitting the emitted light from illumination unit 140 to target position 112. Also as... Figure 2 As shown by the dashed lines and arrows, the image capturing device 130 captures an image of the target position 112 on the substrate 110 via the optical device 120. The optical device 120 may include an imaging device 120, which has a portion for guiding light from the target position 112 to the image capturing device 130.

[0062] The evaluation system 100 includes a control unit 150. The control unit 150 is connected to an image capture device 130 and an illumination unit 140, respectively. The control unit 150 is configured to execute an imaging sequence, wherein the imaging sequence includes at least one image trigger signal and at least one illumination trigger signal. The control unit 150 is configured to send at least one image trigger signal to the image capture device 130 and at least one illumination trigger signal to the illumination unit 140. If the image capture device 130 receives an image trigger signal, the image capture device 130 is configured to capture an image of a target location 112 on the substrate 110. If the illumination unit 140 receives an illumination trigger signal, the illumination unit 140 is configured to illuminate the target location 112 on the substrate 110.

[0063] Evaluation system 100 can be configured to evaluate substrate 110 based on at least one image. For example, control unit 150 or a second control unit (not shown) may be configured to determine at least one of parameters and conditions of substrate 110. Parameters may be evaluation metrics based on at least one image. Evaluation metrics may indicate the state, condition, and / or shape of substrate 110 and / or patterns on substrate 110.

[0064] refer to Figure 3 The diagram illustrates an apparatus 200 and a system 100 for evaluating a substrate 110 according to some embodiments. The apparatus 200 includes an evaluation system 100 and a platform 210 according to some embodiments. The platform 210 is shown as a solid object / plate. Figure 3 The evaluation system 100 is adapted for evaluating the reflectance measurement of a substrate, and the platform 210 may be opaque. If the evaluation system 100 is suitable for both reflectance and transmission measurements, the platform 210 may include a light-transmitting material. In some embodiments, the platform 210 may include a holder. The substrate 110 is disposed on the platform 210. The platform 210 may be configured to move relative to the optics 120 and / or image capture device 130 of the evaluation system 100. The optics 120 and / or image capture device 130 of the evaluation system 100 may be configured to move relative to the platform 210, thereby moving relative to the substrate 110 disposed on the platform 210. It should be noted that... Figure 3 The evaluation system 100 of the device 200 shown has the same characteristics as... Figure 2 Several common features of the evaluation system 100 shown are described here. (See reference here.) Figure 2 And related texts to enhance understanding of these features of the evaluation system 100.

[0065] like Figure 3As shown, the evaluation system 100 includes an optical device 120, which includes an objective lens 122. The objective lens 122 is the optical component included in the optical device 120 closest to the substrate 110. The objective lens 122 is configured to focus light onto / from a target position 112 on the substrate 110, which... Figure 3 The dashed arrow between objective lens 122 and substrate 110 is shown in the middle. Similarly, as... Figure 3 As shown, the evaluation system 100 includes at least one position sensor 160. The position sensor 160 is configured to generate position data indicating the position of the objective lens 122 relative to the substrate 112. The position sensor 160 may be configured to measure the position of the objective lens 122 and / or the substrate 110 and / or the distance to the objective lens 122 and / or the substrate 110, thereby indicating the position of the objective lens 122 relative to the substrate 110. For example, as... Figure 3 As shown by the dashed line, the position sensor 160 can be configured to generate position data indicating the position of the objective lens 122 relative to the substrate 112 by measuring the position or distance of the objective lens 122 and the position or distance of the platform 210 on which the substrate 110 can be arranged. The position sensor 160 is connected to the control unit 150. The control unit 150 is configured to receive position data from at least one position sensor 160 and execute an imaging sequence based on the position data. For example, the position data may indicate a position of the objective lens 122 relative to the substrate 110, which corresponds to a target position 112 on the substrate 110 to be evaluated. The control unit 150 may then execute an imaging sequence at the target position 112. The evaluation system 100 can be configured to evaluate the substrate 110 based on at least a portion of the position data. For example, the control unit 150 may be configured to determine parameters and / or conditions of the substrate 110, such as evaluation metrics, based on at least one image and at least a portion of the position data.

[0066] like Figure 3 As shown, the control unit 150 may include a timer 152 and is configured to run the timer 152. The timer 152 may be configured to generate pulses / signals / cues / indications at regular time intervals. The timer 152 may be synchronized with the position sensor 160 and the execution / running of the imaging sequence. For example, the position sensor 160 may indicate the position on the substrate 110 to be evaluated, and the control unit 150 may be configured to run the timer 152 to execute the imaging sequence based on the timer 152.

[0067] The evaluation system 100 includes secondary sensors 170, such as Figure 3As shown. The secondary sensor 170 can be a pneumatic sensor, optical sensor, inductive sensor, accelerometer, or temperature sensor. The auxiliary sensor 170 can generate sensor data based on the performed measurement. At least one secondary sensor 170 can be connected to at least one of the optical device 120, image capture device 130, illumination unit 140, position sensor 160, and platform 210 to perform a measurement of at least one of the optical device 120, image capture device 130, illumination unit 140, position sensor 160, and platform 210, and the substrate 110 can be arranged / placed in the platform 210. As an example, the secondary sensor 170 can be an inductive sensor connected to the platform 210 to measure the position of the platform 210. As another example, the secondary sensor 170 can be an optical sensor connected to the optical device 120 to measure the distance from the objective lens 122 to the substrate 110.

[0068] Evaluation system 100 can be configured to evaluate substrate 110 based on at least a portion of sensor data. For example, control unit 150 can be configured to determine parameters and / or conditions, such as evaluation metrics, of substrate 110 based on at least one image, at least a portion of position data, and at least a portion of sensor data. The accuracy and fidelity of evaluation system 100 can be improved by combining sensor data with position data from position sensor 160 and images captured by image capture device 130. For example, secondary sensor 170 may include a temperature sensor configured to measure thermal disturbances / changes in evaluation system 100 (e.g., in one or more components of evaluation system 100). Therefore, if control unit 150 executes an imaging sequence, sensor data received by control unit 150 during the imaging sequence from temperature sensor 170 can be combined with and time-synchronized with the captured images and position data.

[0069] In one example, the evaluation system 100 includes a second control unit (not shown) configured to determine parameters and / or conditions, such as evaluation metrics, of the substrate 110 based on at least one of at least one image, location data, and sensor data. The second control unit may be located external to the evaluation system 100, but may still be wirelessly or connected via cable / wire.

[0070] Evaluation system 100 includes a data storage device 180. The data storage device 180 is configured to store evaluation data. The evaluation data includes at least one of at least an image, position data, sensor data, and log data of at least one image trigger signal and at least one illumination trigger signal. The data storage device 180 may be connected to at least one of a control unit 150, an image capture device 130, an illumination unit 140, a position sensor 160, and a secondary sensor 170. In other words, the data storage device 180 can receive and store data from components of the evaluation system, for example, for further processing. The data storage device 180 may be connected to a second control unit (not shown). Because the evaluation data can be stored in the data storage device 180, references can be made between different datasets in the evaluation data to create a data log. A dataset may be, for example, position data generated by at least one position sensor 160, sensor data generated by the secondary sensor 170, or at least one image captured by the image capture device 130 during an imaging sequence or an evaluation run performed by the evaluation system. For example, the position data may include references to at least one image, such that the position data can be associated with at least one image. In another example, the sensor data may include a first reference to at least one image. Furthermore, the sensor data may include a second reference to location data associated with at least one image generated by at least one location sensor. In other words, the sensor data may include a reference to at least one of the location data and at least one image. A reference may be made between the dataset in the evaluation data and the time generated by the timing unit. The timing unit may be timer 152.

[0071] Evaluation system 100 can be configured to generate at least one processed image based on at least one of evaluation data, parameters, and conditions. Furthermore, evaluation system 100 can be configured to generate a processed image based on multiple images captured by image capture device 130. For example, evaluation system 100 can be configured to generate a processed image by averaging multiple images and / or by weighted averaging (possibly in combination with parameters and / or conditions of substrate 110). Control unit 150 can be configured to generate at least one processed image. Evaluation system 100 can be configured to determine parameters and / or conditions of substrate 110 based on the processed image.

[0072] refer to Figure 4A schematic diagram of an apparatus 200 for evaluating a substrate 110 according to some embodiments is shown. The apparatus 200 includes an evaluation system 100 and a platform 210 according to some embodiments. The substrate 110 is disposed on the platform 210. The platform 210 can be configured to move relative to the optical device 120 and / or image capture device 130 of the evaluation system 100. The optical device 120 and / or image capture device 130 of the evaluation system 100 can be configured to move relative to the platform 210, thereby moving relative to the substrate 110 disposed on the platform 210. It should be noted that... Figure 4 The evaluation system 100 of the device 200 shown has the same characteristics as... Figure 3 The evaluation system 100 of the device 200 shown and Figure 4 The evaluation system 100 of the device 200 shown shares several common features. System 100 in... Figure 2 As shown in [the image]. See here for reference. Figure 2 and Figure 3 And related texts to enhance understanding of these features of the evaluation system 100.

[0073] like Figure 4 As shown, the evaluation system 100 includes an interferometer 162 and an encoder 164. The interferometer 162 is configured to measure / determine the position of the objective lens 122 relative to the substrate 110. This can be accomplished by measuring / determining the position of the objective lens 122 or the distance to the objective lens 122, as well as the position of the substrate 110 or the platform 210 on which the substrate 110 is disposed, or the distance to the substrate 110 or the platform 210 on which the substrate 110 is disposed. This is in Figure 4 The image shows the position of the interferometer 162 to the objective lens 122 and to the indicating platform 210, indicated by dashed lines. The encoder 164 is configured to measure mechanical positions, such as distances from the origin. The encoder 164 is connected to the platform 210. The encoder 164 can measure / determine the mechanical position of the substrate 110 or the platform 210 on which the substrate 110 is disposed. The interferometer 162 and the encoder 164 are connected to the control unit 150 and may also be connected to the data storage device 180. The control unit 150 is connected to the data storage device 180 and can be configured to send evaluation data to the data storage device 180. The position data generated by the interferometer 162 and / or the encoder 162 can be stored / recorded in the data storage device 180.

[0074] refer to Figure 5 A schematic diagram of an evaluation system 100 according to some embodiments is shown. It should be noted that... Figure 5 The evaluation system 100 shown has the same characteristics as... Figure 2 The evaluation system 100 shown and Figures 3 to 4 Several features common to the evaluation system 100 of the device 200 shown herein. (See reference here.) Figure 2-4And related text to enhance understanding of these characteristics of the evaluation system 100. Figure 5 In this configuration, substrate 110 can be disposed in a holder or on a platform. Substrate 110 can be disposed in a holder / platform such that both sides of substrate 110 (the upper and lower sides in the figure) are accessible / visible. Figure 5 In the evaluation system 100, a first optical device 124 and a second optical device 126 are included. The first optical device 124 is disposed between a substrate 110 and an image capturing device 130. The first optical device 124 is disposed on a first side of the substrate 110, which is shown in the figure as the upper / top side of the substrate 110. Thus, in the figure, the first optical device 124 is disposed above the substrate 110. The second optical device 126 is disposed between the substrate 110 and an illumination unit 140. The second optical device 126 is disposed on a second side of the substrate 110, which is shown in the figure as the lower / bottom side of the substrate 110. Thus, the second optical device 126 is disposed below the substrate 110 in the figure. The image capturing device 130 captures at least one image of a target location 112 via / through the first optical device 124. The illumination unit 140 illuminates the target location 112 via / through the second optical device 126.

[0075] exist Figure 5 In the diagram, dashed lines and arrows indicate the optical paths used for illumination and image capture. (Example:) Figure 5 As shown, illumination (e.g., emitted light) from illumination unit 140 is guided / transmitted to target position 112 on substrate 110 via second optical device 126. Thus, target position 112 is illuminated from below in the figure. Second optical device 126 may include an illumination section having an illumination light path for guiding / transmitting emitted light from illumination unit 140 to target position 112. Furthermore... Figure 5 As shown by the dashed lines and arrows, an image of the target position 112 of the substrate 110 is captured by the image capturing device 130 via the first optical device 124. The first optical device 124 may include an imaging section having an imaging optical path for guiding light from the target position 112 to the image capturing device 130. With this arrangement, Figure 5 The evaluation system 100 is suitable for transmission measurement used to evaluate substrate 110.

[0076] In one example, illumination / emitted light from illumination unit 140 can also be guided / transmitted to target position 112 on substrate 110 via first optical device 124. This is also shown below: the figure shows a dashed arrow from illumination unit 140 to optical device 124. Therefore, target position 112 can be illuminated from above in the figure. Thus, reflection measurements for evaluating substrate 110 can also be performed by evaluation system 100. Therefore, Figure 5The example of the evaluation system 100 illustrated is suitable for evaluating a substrate using transmission and / or reflection measurements. At least one image can be captured using transmission measurement, i.e., illuminating the substrate 110 from one side and capturing at least one image from the other side. At least one image can be captured using reflection measurement, i.e., illuminating the substrate 110 from the same side where the image is captured. Images captured by transmission and reflection measurements can be used in combination for substrate evaluation, for example, via control unit 150 and / or a second control unit. This can improve the evaluation; for example, it can more easily distinguish substrate defects and contaminants such as dirt / dust.

[0077] refer to Figures 6A-6F An example of an imaging sequence that can be executed by the control unit 150 is shown. Figures 6A-6F In this diagram, position data 16a, 16c-1, 16c-2, 16e, and 16f are shown as a function of time T. The position of the substrate relative to the image capturing device and / or optical apparatus is shown in nanometers [nm] on the vertical axis, and time T is shown on the horizontal axis. Position data 16a, 16c-1, 16c-2, 16e, and 16f may include data regarding position in a direction parallel to the X-axis, and / or data regarding position in a direction parallel to the Y-axis, and / or data regarding position in a direction parallel to the Z-axis, wherein the Y-axis is perpendicular to the X-axis, and wherein the Z-axis is perpendicular to both the X-axis and the Y-axis. Where the position data includes data along the Z-axis, the position data regarding position along the Z-axis may be determined by, for example, a pneumatic sensor and / or an optical sensor. In other words, at least one position sensor may include at least one of a pneumatic sensor and / or an optical sensor configured to generate position data indicating the position of the substrate relative to the objective lens along the Z-axis.

[0078] Time T can be set by a clock / timing unit. The timing unit can be a timer included in the control unit of the evaluation system. Imaging sequences can be executed based on the timer, thus image capture and illumination can be performed based on time T. The timer and position data 16a, 16c-1, 16c-2, 16e, and 16f can be synchronized.

[0079] A window signal can be defined in the imaging sequence over time intervals. A window signal can be considered as a signal having zero values ​​outside the selected interval (e.g., the time interval over which it is defined). The window signal can be symmetrical, for example, symmetrical in amplitude over time. The window signal can be set / adjusted / configured to capture fluctuations in the position data, which can then be taken into account when evaluating the substrate. For example, the window signal can be configured to capture fluctuation patterns, such as at least partially periodic fluctuations in one or more dimensions (e.g., the X and Y directions). Therefore, the control unit of the evaluation system can be configured to determine a first position of the substrate based on position data from time intervals corresponding to the image window signal and / or the illumination window signal. The control unit can also be configured to determine a deviation of the position data from the time interval corresponding to at least one image window signal and / or at least one illumination window signal, such as periodic fluctuations, and determine the first position based on the determined deviation.

[0080] exist Figure 6A In the imaging sequence, the first image window signal 13a-1 and the second image window signal 13a-2, as well as the first illumination window signal 14a-1 and the second illumination window signal 14a-2, are included. Figure 6A Position data 16a is shown. Position data 16a can be generated by a position sensor included in the evaluation system. In the figure, position data 16a can show the position of the substrate relative to the optical device and / or image acquisition device in one of the X, Y, or Z dimensions. The position of the substrate relative to the image acquisition device and / or the optical device indicated by position data 16a remains as stationary as possible during image acquisition, but there are still small fluctuations in position, which are shown by the peak values ​​of the changes in position data 16a. For example, in Figure 6A In this process, position data 16a can indicate the position of the substrate in the X dimension, meaning that the substrate is kept as stationary as possible in the X direction. The substrate can also be kept as stationary as possible in the Y and Z dimensions. Imaging sequences can then be performed while the substrate is kept as static as possible in three dimensions. Position data 16a can correspond to the target position, i.e., the desired location on the substrate to be evaluated.

[0081] exist Figure 6AIn [the figure], the first image window signal 13a-1 and the second image window signal 13a-2 are defined over a time interval T, as shown by the solid lines. The first image window signal 13a-1 is defined within the time interval from t2 to t3, which means the first image window signal 13a-1 starts at time t2 and ends at time t3. The second image window signal 13a-2 is defined within the time interval from t6 to t7, which means the second image window signal 13a-2 starts at time t6 and ends at time t7. The first illumination window signal 14a-1 and the second illumination window signal 14a-2 are defined over the time interval T, as shown by the dashed lines. The first illumination window signal 14a-1 is defined within the time interval from t1 to t4, which means the first illumination window signal 14a-1 starts at time t1 and ends at time t4. The second illumination window signal 14a-2 is defined within the time interval from t5 to t8, which means the second illumination window signal 14a-2 starts at time t5 and ends at time t8. As Figure 6A shown, the first illumination window signal 14a-1 completely overlaps with the first image window signal 13a-1 because the first illumination window signal 14a-1 and the first image window signal 13a-1 have the relationship that t1 < t2 < t3 < t4. This also applies to the second image window signal 13a-2 and the second illumination window signal 14a-2, where the second illumination window signal 14a-2 completely overlaps with the second image window signal 13a-2 because t5 < t6 < t7 < t8.

[0082] In Figure 6B [the figure], the position data 16a is shown. The position data 16a was described above with respect to Figure 6A [a certain situation], and this also applies to Figure 6B . Additionally, in Figure 6B [the figure], the imaging sequence includes the first image window signal 13b-1 and the second image window signal 13b-2 (solid lines), as well as the first image window signal 13b-1 and the second image window signal 13b-2 (solid lines). In Figure 6B [the figure], the first image window signal 13b-1 is defined within the time interval from t1 to t4, which means the first image window signal 13b-1 starts at time t1 and ends at time t4. The second image window signal 13b-2 is defined within the time interval from t5 to t8, which means the second image window signal 13b-2 starts at time t5 and ends at time t8. The first illumination window signal 14b-1 is defined within the time interval from t2 to t3, which means the first illumination window signal 14b-1 starts at time t2 and ends at time t3. The second illumination window signal 14b-2 is defined within the time interval from t6 to t7, which means the second illumination window signal 14b-2 starts at time t6 and ends at time t7. As Figure 6BAs shown, the first image window signal 13b-1 completely overlaps with the first illumination signal 14b-1 because the first image window signal 13b-1 overlaps with the first illumination signal 14b-1. The same is true for t1 < t2 < t3 < t4 with respect to the second image window signal 13b-2 and the second illumination window signal 14b-2, where the second image window signal 13b-2 completely overlaps with the second illumination window signal 14b-2 because t5 < t6 < t7 < t8.

[0083] In Figure 6C position data 16c-1 and position data 16c-2 are shown. As an example, Figure 6C the position data 16c-1 and 16c-2 in Figure 6C can show two-dimensional position data generated by a position sensor included in the evaluation system. For example, the position data 16c-1 can show the position of the substrate in the X dimension relative to the optical device and / or the image capture device, and the position data 16c-2 can show the position of the substrate in the Y dimension relative to the optical device and / or the image capture device. As described above, during image capture, the position of the substrate relative to the image capture device and / or the optical device is kept as stationary as possible, but there are still small fluctuations in the position, which are shown by the peak changes in the position data 16c-1 and 16c-2 respectively. For example, while the substrate is kept as stationary / static as possible along the X-axis and Y-axis, the

[0084] imaging sequence in Figure 6C is performed. The position data 16c-1 and 16c-2 can correspond to the target positions, i.e., the positions on the substrate that are desired to be evaluated. The evaluation system can be configured to also evaluate the substrate based on the position fluctuations. The fluctuations in the position can be recorded in a data memory and used to evaluate the substrate.

[0084] [[ID=1第十二,在 Figure 6C 中,成像序列包括第一图像窗口信号13c-1和第二图像窗口信号13c-2(实线)以及第一照明窗口信号14c-1和第二照明窗口信号14c-2(虚线)。在 Figure 6C 中,第一图像窗口信号13c-1被限定在时间间隔t2至t4中,这意味着第一图像窗口信号13c-1在时间t2开始并且在时间t4结束。第二图像窗口信号13c-2被限定在时间间隔t6至t8中,这意味着第二图像窗口信号13c-2在时间t6开始并且在时间t8结束。第一照明窗口信号14c-1被限定在时间间隔t1至t3中,这意味着第一照明窗口信号14c-1在时间t1开始并在时间t3结束。第二照明窗口信号14c-2被限定在时间间隔t5至t7中,这意味着第二照明窗口信号14c-2在时间t5开始并在时间t7结束。如 Figure 6CAs can be seen, the first image window signal 13c-1 and the first illumination window signal 14c-1 partially overlap because the first image window signal 13c-1 and the first illumination window signal 14c-1 overlap with each other. t1 < t2 < t3 < t4. The same applies to the second image window signal 13c-2 and the second illumination window signal 14c-2, where the second image window signal 13c-2 and the second illumination window signal 14c-2 partially overlap because t5 < t6 < t7 < t8.

[0085] In Figure 6D position data 16a is shown. The position data 16a was described above with respect to Figure 6A and the same applies to Figure 6D . In addition, in Figure 6D the imaging sequence includes first, second, third, and fourth image window signals 13d-1, 13d-2, 13d-3, 13d-4 (solid lines) and first, second, third, and fourth illumination window signals 14d-1, 14d-2, 14d-3, 14d-4 (dashed lines). In Figure 6D it is illustrated that the imaging sequence can include multiple image window signals and multiple illumination window signals defined during different lengths of time intervals and at different time points. For example, the first image window signal 13d-1 and the first illumination window signal 14d-1 completely overlap, and the fourth image window signal 13d-4 and the fourth illumination window signal 14d-4 partially overlap with each other. As Figure 6D shown, the illumination window signals and the illumination window signals in the imaging sequence can overlap with each other in different ways. The imaging sequence can be customized according to the evaluation of the substrate to be performed.

[0086] In Figure 6E position data 16e and the imaging sequence are shown. The position data 16e can be generated by a position sensor included in the evaluation system. The position data 16e in the figure shows the change in the position of the substrate with respect to the image acquisition device and / or the optical device in one direction among the X dimension, Y dimension, or Z direction over time T. Thus, during the movement of the substrate with respect to the image acquisition device and / or the optical device in one dimension, Figure 6EThe imaging sequence is described. The Z direction may be referred to as the Z dimension. The position of the substrate relative to the image capture device and / or optics, indicated by position data 16e, changes during image capture, but small fluctuations in position still occur, indicated by the peaks of the changes in position data 16e. For example, if the position of the substrate relative to the image capture device and / or optics changes in the X dimension, the substrate moves relative to the image capture device and / or optics along the X-axis. The imaging sequence and image capture are then performed during this relative movement in the X dimension. The evaluation system or its control unit may be configured to receive a position sequence comprising a set of target positions. The position sequence may describe the movement of the substrate relative to the image capture device and / or optics in one or more dimensions. For example, the target positions may include XY coordinates corresponding to positions on the substrate. Thus, the movement of the substrate relative to the image capture device and / or optics may be along the X-axis and / or along the Y-axis. The evaluation system or control unit may be configured to move the focus of the optics between one or more target positions in the position sequence. For example, the evaluation system or control unit may be configured to move the focus from a first target position to a second position, and so on. That is, iterating over the set of target positions. It should be understood that the movement of the focal spot is a movement of the optical device relative to the substrate. Therefore, in some embodiments, the platform on which the substrate is disposed may be moved, and in some embodiments, the optical device or the objective lens included in the optical device may be moved. In some embodiments, the evaluation system or control unit may command an external control unit outside the evaluation system to control the movement of the focal spot.

[0087] In this example, the focus can be moved in the X direction, i.e., along the X-axis. The X-coordinate value can then be changed between a first target position and a second target position in a position sequence. By receiving the position sequence, the control unit can control the movement of the substrate relative to the image acquisition device and / or the optical device along the X-axis. The movement of the focus can be synchronized with time T. Figure 6E In this diagram, the vertical axis can indicate the position of the substrate relative to the image capturing device and / or optical apparatus along the X-axis. For example, the position of the substrate along the X-axis relative to the image capturing device and / or optical apparatus can change at a rate of approximately 1 pm / s. Figure 6E As shown, an imaging sequence is performed during this movement. The evaluation system can be configured to generate processed images based on multiple images captured during the movement, such as... Figure 6E The image shown.

[0088] In the example, the predetermined (or preset) position sequence may include a set of target positions, which include predetermined XY coordinates. The predetermined XY coordinates may be approximate desired target positions, indicating, for example, a desired position on the substrate at a certain point in time. The XY coordinates may correspond to the movement of the substrate relative to the image capturing device and / or optical apparatus in the X and / or Y directions. Figure 6E As shown, the position data 16e changes with time T, which can correspond to such movement. The imaging sequence may include, for example, four image window signals and four image window signals. Illumination window signals, such as... Figure 6E As shown. The imaging sequence can be synchronized temporally with a predetermined location sequence. Therefore, as... Figure 6E As shown, four images can be captured during movement in the X and / or Y directions. Therefore, movement of the substrate relative to the image acquisition device and / or optics in the X and / or Y directions, along with the imaging sequence, can be performed simultaneously. The position sequence can represent movement over short distances, e.g., during image capture; thus, the difference between the first and second XY coordinates can be small in either dimension / direction, e.g., on the micrometer and / or nanometer scale. Position data 16e, image window signals, illumination window signals, and optionally sensor data from at least one secondary sensor can be stored (or recorded) in a data storage device for evaluation at a later stage. The stored and / or recorded data can be time-indexed, meaning that the value of each record corresponds to a specific moment, which can be determined by a timer, thus allowing for chronological sorting and time-based analysis.

[0089] exist Figure 6F The figure shows position data 16f and an imaging sequence. Position data 16f can be generated by a position sensor included in the evaluation system. Position data 16f in the figure shows that the position of the substrate relative to the image capture device and / or optical device in one of the X, Y, or Z dimensions changes partially over time T, and partially remains stationary / remains as stationary as possible over time T. Figure 6F This illustrates that during an imaging sequence, the position of the substrate relative to the image capture device and / or optical apparatus can be changed in combination while maintaining the position as stationary as possible. The evaluation system or its control unit can be as described above regarding... Figure 6E The control unit is configured to receive a position sequence comprising a set of target locations. The control unit can be configured to run a timer based on the position sequence; for example, the control unit can be configured to start the timer at certain locations. For instance, if position data 16f indicates a target location in the position sequence, the control unit can be configured to start / run the timer and perform an imaging sequence and / or send at least one image trigger signal and at least one illumination trigger signal based on the timer at the indicated target location. Figure 6FAs shown, the position of the substrate relative to the optical device and / or image capturing device remains as stationary as possible during two time intervals, and changes between these two time intervals. For example, position data 16f can indicate a first target position in a position sequence. The control unit can then be configured to send at least one image trigger signal and at least one illumination trigger signal. Figure 6F As shown, the first image trigger signal includes a first image window signal defined in time intervals t2 to t5, and the first illumination trigger signal includes a first illumination window signal defined in time intervals t1 to t4. Then, position data 16f can indicate a second target position in the position sequence. The control unit can then be configured to send at least one image trigger signal and at least one illumination trigger signal. Figure 6F As shown, the second image trigger signal includes a second image window signal defined in time intervals t6 to t7, and the second illumination trigger signal includes a second illumination window signal defined in time intervals t5 to t8. At the second target position, the control unit sends a third image trigger signal and a third illumination trigger signal. Figure 6F As shown, the third image trigger signal includes a time interval t 10 To t 11 The third image window signal is defined in the middle, and the third illumination trigger signal is included in the time interval t9 to t9. 12 The signal is defined by a third illumination window. Therefore, different types of imaging sequences can be performed at different target locations in the position sequence.

[0090] refer to Figure 7 The diagram illustrates example operations of an evaluation system according to some embodiments. Figure 7 The figure illustrates the operation of some devices of the evaluation system relative to time T. Time T can be set by a timing unit. The figure shows image trigger signals 420 and / or illumination trigger signals 430 sent from the control unit of the evaluation system to the image capture device and / or illumination unit of the evaluation system. Image trigger signal 420 may include an image window signal. Illumination trigger signal 430 may include an illumination window signal 430. The figure also shows a timer signal / clock signal 410 generated / set by a timer included in the control unit. Figure 7 The diagram also illustrates the recording / storage of, for example, evaluation data by the evaluation system's data storage over time T. The control unit of the evaluation system can be configured to run a timer. The control unit can be configured to send one of at least one image trigger signal 420 and at least one illumination trigger signal 430 based on the timer. (As shown in...) Figure 7As seen in the diagram, the timer starts at t1, and an image trigger signal 420, in the form of one or more image window signals, is sent from the control unit and received by the image capture device at t1. Similarly, an illumination trigger signal 430, in the form of one or more illumination window signals, is sent from the control unit and received by the illumination unit at t5. As shown, the example operation includes several image trigger signals 420 and illumination trigger signals 430. Figure 7 As shown, the recording / storage of evaluation data by a data memory is performed throughout the example operation 440. For example, the captured image, image window signal 420, and illumination window signal 430 can be recorded / stored using a reference between them, time T, and other evaluation data acquired during the example operation.

[0091] In the example, the control unit can be configured to receive a position sequence comprising a set of target positions. A timer can be started based on / by the position sequence. For example, if position data from the position sensor of the evaluation system indicates a target position in the position sequence, i.e., the position of the substrate relative to the optical device and / or image capture device corresponds to a target position in the position sequence, then the timer is started. The control unit can then be configured to send one of at least one image trigger signal 420 and at least one illumination trigger signal 430 based on the started timer.

[0092] refer to Figure 8 A flowchart of a method 300 for evaluating a substrate 110 according to a second aspect of the present invention is shown. The method 300 for evaluating the substrate 110 uses an evaluation system according to any embodiment of the first aspect of the present invention. Figure 7 As shown, method 300 includes performing an imaging sequence 310. The imaging sequence includes at least one image trigger signal and at least one illumination trigger signal. Method 300 includes sending at least one image trigger signal from a control unit to an image capturing device 312. Method 300 includes sending at least one illumination trigger signal from a control unit to an illumination unit 314. Method 300 includes capturing an image of a target location 112 on a substrate 110 via an optical device based on at least one image trigger signal 316. Method 300 includes illuminating the target location 112 on the substrate 110 via an optical device by an illumination unit based on at least one illumination trigger signal 318.

[0093] Furthermore, by studying the accompanying drawings, the disclosure, and the appended claims, a person skilled in the art can understand and implement variations of the disclosed examples when practicing the claimed invention. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used for benefit.

[0094] A feature described in one aspect may also be combined with other aspects, and the advantages of that feature apply to all aspects to which it is combined. Other objects, features, and advantages of the inventive concept will become apparent from the detailed disclosure, the appended claims, and the drawings.

[0095] Generally, unless otherwise expressly defined herein, all terms used in the claims shall be interpreted according to their ordinary meaning in the art. Furthermore, the use of terms such as “first,” “second,” and “third,” etc., herein does not indicate any order, quantity, or importance, but is used to distinguish one element from another. Unless otherwise expressly stated, all references to “a / an / the [element, device, component, apparatus, step, etc.]” ​​shall be explicitly interpreted as referring to at least one instance of the said element, device, component, apparatus, step, etc. Unless expressly stated otherwise, the steps of any method disclosed herein need not be performed in the exact order disclosed.

Claims

1. An evaluation system (100) for evaluating a substrate (110), the evaluation system comprising: At least one optical device (120) is configured to have a focal point at a target location (112) on the substrate. An image capturing device (130) is configured to capture at least one image of the target location of the substrate via the at least one optical device. An illumination unit (140) is configured to illuminate the target location of the substrate via the at least one optical device. A control unit (150) is configured to execute an imaging sequence, wherein the imaging sequence includes at least one image trigger signal and at least one illumination trigger signal, wherein the control unit is configured to send the at least one image trigger signal to the image capturing device and the at least one illumination trigger signal to the illumination unit. The image capturing device is configured to receive the at least one image trigger signal and capture at least one image based on the at least one image trigger signal, and the illumination unit is configured to receive the at least one illumination trigger signal and illuminate the substrate based on the at least one illumination trigger signal.

2. The evaluation system according to claim 1, wherein, The at least one optical device includes an objective lens (122), and the evaluation system includes at least one position sensor (160) configured to generate position data indicating the position of the objective lens relative to the substrate, and the control unit is configured to receive the position data from the at least one position sensor and perform the imaging sequence based on the position data.

3. The evaluation system according to claim 2, wherein, The at least one position sensor includes at least one of an interferometer (162) and an encoder (164).

4. The evaluation system according to any one of the preceding claims, wherein, The control unit is configured to run a timer (152), and wherein the control unit is configured to be triggered based on the timer to send at least one of the at least one image trigger signal and the at least one lighting trigger signal.

5. The evaluation system according to claim 4, wherein, The control unit is configured to receive a position sequence including a set of target locations, wherein the timer is based on the position sequence.

6. The evaluation system according to any one of the preceding claims, wherein, The at least one image trigger signal includes an image window signal, and wherein the at least one lighting trigger signal includes a lighting window signal.

7. The evaluation system according to claim 6, wherein, The image window signal and the lighting window signal overlap at least partially in time.

8. The evaluation system according to any one of the preceding claims, wherein, The lighting unit includes a laser.

9. The evaluation system according to any one of the preceding claims, wherein the evaluation system includes at least one secondary sensor (170), wherein the control unit is configured to receive sensor data from the at least one secondary sensor, and wherein the at least one secondary sensor includes at least one of a pneumatic sensor, an optical sensor, an inductive sensor, an accelerometer, and a temperature sensor.

10. The evaluation system according to any one of the preceding claims, wherein, The evaluation system includes a data storage device (180) for storing evaluation data, wherein the evaluation data includes at least one of the location data, the sensor data, the at least one captured image, and log data of the at least one image trigger signal and the at least one lighting trigger signal.

11. The evaluation system of claim 10, wherein the evaluation system is configured to determine at least one of parameters and conditions of the substrate based on the evaluation data.

12. The evaluation system according to claim 10 or 11, wherein, The evaluation system is configured to generate at least one processed image based on at least one of the evaluation data, the parameters, and the conditions.

13. The evaluation system according to any one of claims 10 to 12, wherein the evaluation system is configured to compare the evaluation data with predetermined data and generate comparison data, and to determine at least one of the parameters and conditions of the substrate based on the comparison data.

14. The evaluation system according to any one of the preceding claims, wherein the at least one optical device comprises: A first optical device (124) is disposed on a first side of the substrate, wherein the image capturing device is configured to capture at least one image of the target location of the substrate via the first optical device, and A second optical device (126) is disposed on a second side of the substrate, wherein the irradiation unit is configured to irradiate the target position of the substrate via the second optical device. The second side is opposite to the first side.

15. A method (300) for evaluating a substrate using an evaluation system, said evaluation system comprising at least one optical device, an image capture device, an illumination unit, and a control unit, said method comprising: Performing the (310) imaging sequence includes the following steps: At least one image trigger signal is sent from the control unit to the image capture device (312). At least one lighting trigger signal is sent from the control unit to the lighting unit (314). An image of the target location on the substrate (316) is captured by an image capture device based on at least one image trigger signal via at least one optical device. The target position of the (318) substrate is illuminated by the lighting unit based on at least one lighting trigger signal via at least one optical device.

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