Image-based robot registration method and system

Abstract

A system for monitoring alignment of a second component relative to a first component includes a camera and a controller including a processor and a non-transitory memory, the controller is configured to receive a first captured image from the camera when the second component is at a predetermined position relative to the first component, receive a selection of a region of interest (ROI) in the first captured image, identify visible features of the second component within the ROI in the first captured image, receive captured images from the camera during a subsequent operation, identify the second captured image when the second component is expected to be at the predetermined position relative to the first component, and determine if the second component is at the predetermined position relative to the first component based on the second captured image and the identified visible features in the first captured image.

Description

[Technical Field]

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 201435, filed April 29, 2021, the entire disclosure of which is incorporated by reference in its entirety.

[0002] The present disclosure relates generally to alignment of robotic systems, and more particularly to methods and systems for image-based robot alignment. [Background technology]

[0003] Robotic systems are frequently used in various industries, such as product manufacturing, product processing, warehousing, and the like. For example, robotic systems may be used in one or more stages of semiconductor crystal manufacturing and / or semiconductor wafer manufacturing. In one example, a wafer handling robot uses servo motors to control the position of a wafer in a manufacturing process. The wafer position sometimes deviates from its originally set position due to hardware failures or environmental factors, such as bearings, brakes, windings, magnet demagnetization, rotor banding, contamination, electrical noise, electrostatic discharge, electronic component life and fatigue, and the like. Summary of the Invention [Problem to be solved by the invention]

[0004] In at least some known systems for wafer fabrication, slip monitoring takes a relatively long time before the slip (i.e., misalignment) is detected through feedback from a laser scattering inspection tool or defect etch. Because of this delay, many wafers (possibly hundreds of wafers) may be affected by the misalignment before the slip is detected.

[0005] This background section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and / or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. As such, it should be understood that these statements are to be read in this light, and not as admissions of prior art. [Means for solving the problem]

[0006] One aspect of the present disclosure is a system for monitoring the alignment of a second component relative to a first component.

[0007] The system includes a camera positioned in a fixed relationship with the first component and operable to capture images of the first component and the second component during operation of the second component, and a controller including a processor and a non-transitory memory storing instructions executed by the processor to configure the controller to receive a first captured image from the camera when the second component is at a predetermined position relative to the first component, receive a selection of a region of interest (ROI) in the first captured image including at least a portion of the first component and at least a portion of the second component, identify a visible feature of the second component within the ROI in the first captured image, receive captured images from the camera during subsequent operation when the second component is expected to be at the predetermined position relative to the first component, identify a second captured image from the captured images received during the subsequent operation when the second component is expected to be at the predetermined position relative to the first component, and determine whether the second component is at the predetermined position relative to the first component based on the second captured image and the identified visible feature of the second component within the ROI in the first captured image.

[0008] Another aspect is a method for monitoring alignment of a second component relative to a first component, the method including: capturing a first captured image when the second component is at a predetermined position relative to the first component using a camera positioned in a fixed relationship to the first component and operable to capture images of the first component and the second component during movement of the second component; receiving a selection of a region of interest (ROI) in the first captured image including at least a portion of the first component and at least a portion of the second component; identifying a visible feature of the second component within the ROI in the first captured image; receiving captured images from the camera during subsequent movement; identifying a second captured image from the received captured images during subsequent movement when the second component is expected to be at the predetermined position relative to the first component; and determining whether the second component is at the predetermined position relative to the first component based on the second captured image and the identified visible feature of the second component within the ROI in the first captured image.

[0009] Various refinements of the features described with respect to the above aspects exist. Additional features may also be incorporated into the above aspects as well. These refinements and additional features may exist individually or in any combination. For example, the various features described below with respect to any of the illustrated embodiments may be incorporated into the above aspects alone or in any combination. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram of an example system for monitoring the alignment of a first component and a second component. [Figure 2] FIG. 2 is a block diagram of an example of a computing device for use in the system shown in FIG. 1. [Figure 3] FIG. 2 is a top view of a portion of the system shown in FIG. 1. [Figure 4] 2 is an example of an image of a portion of a first component and a second component captured by a camera of the system shown in FIG. 1; [Figure 5] FIG. 5 is a close-up view of a portion of the image shown in FIG. 4. [Figure 6] 2 is a graph of image intensity over a series of images for use in detecting when a second component shown in FIG. 1 is in position relative to a first component. [Figure 7] 1 is a flowchart of an example method for monitoring the alignment of a second component relative to a first component. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present disclosure relates generally to the alignment of robotic systems, and more particularly to methods and systems for image-based robot alignment. Although aspects of the present disclosure are described with respect to semiconductor wafer handling robots and semiconductor wafer processing equipment, these aspects may be applied to the alignment of any other robotic system.

[0012] FIG. 1 is a simplified block diagram of an example system 100 for monitoring the alignment of a first component 102 and a second component 104. More specifically, the system monitors the alignment of the second component 104 relative to the first component 102 during operation of the second component. In an exemplary embodiment, the first component 102 is a semiconductor wafer processing device, and the second component 104 is a semiconductor wafer handling robot. The semiconductor wafer handling robot retrieves a semiconductor wafer (not shown in FIG. 1 ) and positions the semiconductor wafer in a semiconductor wafer processing device so that the semiconductor wafer processing device can perform a process on the semiconductor wafer. The process may be, for example, an annealing process, an etching process, a polishing process, or other semiconductor wafer process. At least a portion of the second component 104 is movable relative to the first component 102. For example, the second component 104 may include an arm that holds the semiconductor wafer and moves relative to the first component 102 to move the wafer into the first component 102.

[0013] The camera 106 is positioned in a fixed relationship with the first component 102 and is operable to capture images of the first component 102 and the second component 104 during operation of the second component 104. The camera 106 is a visible light camera that captures visible light images of at least a portion of the first component 102 and the second component 104 during operation. In other embodiments, the camera 106 may be an infrared camera or other suitable imaging device. In some embodiments, the camera 106 is a video camera, and the images captured by the camera 106 are individual frames of a video captured by the video camera. The camera 106 is positioned relative to the first component 102 to capture images of at least a portion of each of the first component 102 and the second component 104 when the second component 104 is in a predetermined position relative to the first component 102. The predetermined position is the position of the second component 104 relative to the first component 102 during a certain step of operation. For example, when used in semiconductor wafer processing, the predetermined position may be the position of a semiconductor wafer handling robot (second component 104) when stopped to accurately place a semiconductor wafer in a semiconductor wafer processing device (first component 102).

[0014] The controller 108 is communicatively coupled to the camera 106 to receive images captured by the camera 106 and to control the camera 106, such as to adjust camera settings and instruct the camera 106 when to capture images.

[0015] 2 is a block diagram of an exemplary computing device 200 that may be used as or included as part of controller 108. Computing device 200 includes a processor 201, memory 202, media output components 204, input devices 206, and a communications interface 208. Other embodiments include different components, additional components, and / or do not include all of the components shown in FIG.

[0016] Processor 201 is configured to execute instructions. In some embodiments, the executable instructions are stored in memory 202. Processor 201 may include one or more processing units (e.g., a multi-core configuration). As used herein, the term processor refers to a central processing unit, a microprocessor, a microcontroller, a reduced instruction set circuit (RISC), an application specific integrated circuit (ASIC), a programmable logic circuit (PLC), and other circuits or processors capable of performing the functions described herein. The foregoing are examples only, and thus are not intended to limit in any way the definition and / or meaning of the term "processor."

[0017] Memory 202 stores non-transitory computer-readable instructions for performing the techniques described herein. Such instructions, when executed by processor 201, cause processor 201 to perform at least a portion of the methods described herein. That is, the instructions stored in memory 202 configure controller 108 to perform the methods described herein. In some embodiments, memory 202 stores computer-readable instructions for providing a user interface to a user via media output component 204 and receiving and processing input from input device 206. Memory 202 may include, but is not limited to, random access memory (RAM), such as dynamic RAM (DRAM) or static RAM (SRAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), and non-volatile RAM (NVRAM). While illustrated as separate from processor 201, in some embodiments, memory 202 is combined with processor 201, such as in a microcontroller or microprocessor, but may still be referred to separately. The above memory types are examples only and are therefore not limiting as to the types of memory that may be used for storing computer programs.

[0018] Media output component 204 is configured to provide information to a user (e.g., an operator of the system). Media output component 204 is any component capable of conveying information to a user. In some embodiments, media output component 204 includes an output adapter, such as a video adapter and / or an audio adapter. The output adapter is operably connected to processor 201 and operably connected to an output device, such as a display device (e.g., a liquid crystal display (LCD), a light emitting diode (LED) display, an organic light emitting diode (OLED) display, a cathode ray tube (CRT), an "electronic ink" display, one or more light emitting diodes (LEDs)) or an audio output device (e.g., speakers or headphones).

[0019] Computing device 200 includes or is connected to input device(s) 206 for receiving input from a user. Input device 206 is any device that enables computing device 200 to receive analog and / or digital commands, instructions, or other input, including visual, audio, touch, button presses, stylus taps, etc. Input device 206 may include, for example, a variable resistor, an input dial, a keyboard / keypad, a pointing device, a mouse, a stylus, a touch-sensitive panel (e.g., a touchpad or touchscreen), a gyroscope, an accelerometer, a position detector, an audio input device, or any combination thereof. A single component, such as a touchscreen, may function as both an output device for media output component 204 and as input device 206.

[0020] The communication interface 208 allows the computing device 200 to communicate with remote devices and systems, such as the camera 106, remote sensors, remote databases, remote computing devices, etc., and may include multiple communication interfaces for interacting with multiple remote devices or systems. The communication interface may be a wired or wireless communication interface that allows the computing device 200 to communicate with remote devices and systems directly or via a network. The wireless communication interface may include a radio frequency (RF) transceiver, a Bluetooth® adapter, a Wi-Fi transceiver, a ZigBee® transceiver, a near field communication (NFC) transceiver, an infrared (IR) transceiver, and / or any other device and communication protocol for wireless communication. (Bluetooth is a registered trademark of the Bluetooth Special Interest Group, Kirkland, Washington, and ZigBee is a registered trademark of the ZigBee Alliance, San Ramon, California.) The wired communication interface may use any suitable wired communication protocol for direct communication, including, but not limited to, USB, RS232, I2C, SPI, analog, and proprietary I / O protocols. In some embodiments, the wired communication interface includes a wired network adapter that allows computing device 200 to be coupled to a network such as the Internet, a local area network (LAN), a wide area network (WAN), a mesh network, and / or any other network for communicating with remote devices and systems via the network.

[0021] The computer systems described herein may include additional, fewer, or alternative functionality, including those described elsewhere herein. The computer systems described herein may include or be implemented via computer-executable instructions stored on a non-transitory computer-readable medium or media.

[0022] FIG. 3 illustrates the system 100 from above, e.g., from the position of the camera 106. The controller 108 and camera 106 are not shown in FIG. 3. As seen in FIG. 3, the exemplary second component 104 includes a movable arm 300 that holds a wafer 302. The second component 104 positions the wafer 302 inside a chamber 304 of the first component 102. The arm 300 extends into the chamber 304 beyond a base portion 306 of the first component. In the exemplary embodiment, the arm 300 includes a distinct visible feature that is a cutout 308 that reveals a portion of the first component 102 from the perspective of the camera 106. The visible feature can be any visible feature that is identifiable by the controller 108. In other embodiments, the arm 300 includes a different visible feature (e.g., a protrusion, a through-hole, an imprint, etc.) or includes an added distinct visible feature (e.g., a distinctly colored or shaped sticker / mark, a QR code, etc.).

[0023] The camera 106 captures an image of the image area 310. The memory 202 stores instructions executed by the processor 201 to configure the controller 108 to receive a first captured image (of the image area 310) from the camera 106 when the second component 104 is in a predetermined position relative to the first component 102. This first image is captured when the second component 104 is known to be in a predetermined position. For example, a user may place the second component 104 in a predetermined position or adjust the position of the second component 104 to place the second component 104 in a predetermined position. Thus, this first image is an image of the correct predetermined position, such as a position to properly align a wafer for processing by the first component 102.

[0024] 4 is an example image 400 of image region 310. As can be seen, base portion 306 is a different color (or darker color) than arm 300. Cutout 308 in arm 300, through which part of base portion 306 is visible, is a visually distinguishable feature in image 400.

[0025] The controller 108 receives a selection of a region of interest (ROI) 402 in the first captured image 400. In an exemplary embodiment, the region of interest 402 includes a portion of the first component 102 and a portion of the second component 104. Alternatively, the region of interest may include only a portion of the second component 104 (e.g., if the visible feature is a sticker completely surrounded by the arm 300). The region of interest 402 may be selected manually by a user, such as by using the input device 106. In other embodiments, the region of interest 402 is selected by the controller 108, such as by performing object detection and recognition on the image to identify the first component 102 and the second component 104 and / or the visible feature.

[0026] 5 is a close-up view of portion 404 in image 400. Controller 108 is configured to identify a visible feature (e.g., notch 308) of second component 104 within region of interest 402 in the first captured image. In this embodiment, controller 108 specifically identifies a corner 500 of notch 308 within region of interest 402. In an exemplary embodiment, controller 108 identifies corner 500 in first image 400 based on intensity values ​​of pixels within first image 400. That is, base portion 306 is identified in image 400 by its darker color, and arms 300 are identified by a lighter color (and different intensity value) than darker-colored base portion 306. The intersecting imaginary line indicating the transition (as determined from the intensity values) between base portion 306 within region of interest 402 in image 400 and arms 300 within region of interest 402 in image 400 is corner 500. In other embodiments, the controller 108 identifies the visual feature by receiving a selection of the visual feature from a user input.

[0027] Once a visible feature (e.g., corner 500) is identified, controller 108 determines first coordinates of the identified visible feature of the second component within the region of interest in first captured image 400. The coordinates are the X and Y coordinates (as identified in FIG. 4 ) of the point where the visible feature is located within image 400. The X and Y coordinates may be determined, for example, by the location of the center pixel of the visible feature within image 400. Controller 108 then stores the first coordinates in memory. Controller 108 also determines coordinates of the region of interest 402 and stores the region of interest coordinates in memory 202. The region of interest coordinates may be two coordinates, such as coordinates of diagonally opposite corners, a single coordinate of one corner along with the dimension and orientation of region of interest 402 relative to that corner, or any other suitable coordinate or coordinates identifying the location of region of interest 402.

[0028] Because the camera 106 is fixed relative to the first component 102 and only captures images of the same image area 310, the visible feature will be at the same location (i.e., the same XY coordinates) within the captured image whenever the arm 300 is in position. The first coordinates can therefore be used to determine whether the arm 400 is in position during subsequent movements.

[0029] Thus, the controller 108 is configured to receive captured images from the camera 106 during subsequent operation. The controller identifies a second captured image from the received captured images during subsequent operation when the second component 104 is expected to be in a predetermined position relative to the first component 102. The time when the second component 104 is expected to be in a predetermined position relative to the first component 102 may be determined by instructions for controlling the second component 104. For example, if the controller 108 also controls the second component 104, the controller 108 knows from the instructions and / or communications from the second component 104 that the second component 104 is expected to be in a predetermined position. That is, when the second component is in a step of processing where the second component 104 should be in a predetermined position, the controller 108 knows that the second component 104 should be in a predetermined position, and the image captured at this time is used as the second captured image.

[0030] In other embodiments, the controller 108 determines that the second component 104 is expected to be in a predetermined position based on an analysis of captured images. For example, FIG. 6 is a graph of image intensity at two points in an image captured by the camera 106 over time (or, more specifically, across a series of video frames if the camera 106 is a video camera). The two points are selected so that when the second component 104 is in position, one point is on the first component 102 in the image and one point is on the second component 104 in the image. For example, the upper left and lower left corners of the region of interest 402 shown in FIGS. 4 and 5 can be used as the two points. As discussed above, in this example, the base portion 306 is darker than the arm 300. Therefore, when the arm 300 is not in position, both points in the image have a relatively low intensity because they are points on the base portion. As the arm 300 moves into position, the intensities of the points visible in the image may change because what is located at the two points changes. When the arm 300 is in position, it stops for a period of time to place the wafer on the first component 102, with one point on the base (and having low intensity) and one point on the arm (and having high intensity). Thus, when the intensity of the point associated with the arm 300 is relatively high and stable for a period of time, the arm 300 is determined to be in position, and the image captured at this time is used as the second captured image. In yet another embodiment, the controller 108 determines that the second component 104 is expected to be in position by locating and tracking a visible feature through multiple captured images. When the visible feature is within the region of interest 402 and has not moved for a period of time, the controller 108 determines that the second component 104 is expected to be in position, and the image captured at this time is used as the second captured image.

[0031] The controller 108 identifies visible features of the second component 104 in the second captured image. In the exemplary embodiment where the visible features are the corners 500 of the notch 308, the Features from Accelerated Segment Test (FAST) algorithm is used. The FAST algorithm detects any corners of the region of interest such that significance gives a clear difference in pixel intensity around the corner. The number of corners detected depends on the threshold value of the FAST function. The format of FAST is: FAST(InputArray image, std::vector <keypoint>& keypoints,int threshold,bool nomaxSuppression=true). The lower the threshold, the more corners are detected. An appropriate threshold for all images to return only one corner can be determined by looping through the threshold from 200 to 1.

[0032] Although the exemplary embodiment uses corners, any point can be used as a reference as long as it has different pixel intensities in the region of interest 402. For example, a black spot or a white spot can be used as a visible feature. Instead of using OPENCV's FAST function, the location of the black or white spot can be found by analyzing the pixel intensities within the region of interest 402. This is simply calculated using the "minMaxLoc" function: cv::minMaxLoc(ROI,&min,&max,&min_loc,&max_loc), where min_loc is used if the visible feature is darker around it than the area around it (a black spot) and max_loc is used if the visible feature is lighter around it than the area around it (a white spot).

[0033] After the visible features are identified in the second captured image, the controller 108 determines whether the second component 104 is in a predetermined position relative to the first component 102 based on the second captured image and the identified visible features of the second component 104 within the region of interest 402 in the first captured image. In some embodiments, the controller 108 determines second coordinates of the identified visible features of the second component in the second captured image. The second coordinates are X and Y coordinates of the location of the visible features in the second captured image. If the second component 104 is properly in position, the second coordinates should match the first coordinates determined from the first captured image. Thus, the controller 108 is configured to determine whether the second component 104 is in a predetermined position relative to the first component 102 by comparing the second coordinates with the first coordinates.

[0034] In some embodiments, the second component 104 is determined to be in position relative to the first component 102 when the second coordinate is the same as the first coordinate. Alternatively, the second component 104 may be determined to be in position relative to the first component 102 when the second coordinate is within a threshold distance of the first coordinate. The threshold distance may be selected to account for slight variations that may occur in the detection of images or visible features, or to allow for some acceptable variation in the positioning of the second component 104.

[0035] When the controller 108 expects the second component 104 to be in position but determines that it is not, the controller 108 can generate an alarm. That is, when the controller 108 determines that the second component 104 is expected to be in position but a visible feature in the second captured image does not have a second coordinate equal to (or within a threshold distance of) the first coordinate, the controller 108 generates an alarm. The alarm can be a human-perceivable alarm, such as a flashing light or siren, a computer-perceivable alarm, such as an alarm message sent to a system controller, or both. In response to the alarm, a user can adjust or repair the second component 104 as necessary to return it to proper alignment with the first component 102.

[0036] 7 is a flowchart of an example method 700 for monitoring the alignment of a second component relative to a first component. The method may be performed by system 100 and its components, or may be used in conjunction with other suitable systems or components.

[0037] The logic flows depicted in the figures do not require the particular order shown or sequential order to achieve desirable results. Furthermore, other steps may be provided in the described flows or steps may be eliminated, and other components may be added or removed from the described systems. Accordingly, other embodiments are within the scope of the following claims.

[0038] It will be understood that the above embodiments, which have been particularly described in detail, are merely examples or possible embodiments, and that many other combinations, additions, or alternatives are possible.

[0039] Additionally, the specific naming of components, term capitalization, attributes, data structures, or other programming or structural aspects are not required or important, and mechanisms implementing the present disclosure or its functionality may have different names, formats, or protocols. Furthermore, the present system may be implemented using a combination of hardware and software as described, or entirely in hardware elements. Additionally, the specific division of functionality among various system components described herein is merely exemplary and not required. Functions performed by a single system component may instead be performed by multiple components, and functions performed by multiple components may instead be performed by a single component.

[0040] Approximate language, as used herein throughout the specification and claims, can be applied to modify any quantitative expression that can vary within permissible limits without resulting in a change in the basic function to which it relates. Thus, values ​​modified by one or more terms, such as "about" and "substantially," are not limited to the exact value specified. In at least some instances, approximation language may correspond to the precision of an instrument for measuring the value. Throughout the specification and claims, range limitations can be combined and / or interchanged, and such ranges are specified and include all subranges contained therein, unless the context or language indicates otherwise.

[0041] Various changes, modifications, and alterations in the teachings of the present disclosure may be considered by those skilled in the art without departing from the intended spirit and scope thereof, and it is intended that the present disclosure cover such changes and modifications.

[0042] This specification uses examples to explain the disclosure, including the best mode, and also to enable those skilled in the art to practice the disclosure, including making and using any devices or systems, and performing any methods incorporated therein. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims.< / keypoint>

Claims

1. 1. A system for monitoring alignment of a second component relative to a first component, the system comprising: a camera positioned in fixed relation to the first component and operable to capture images of the first component and the second component during operation of the second component, one of the first component and the second component being darker than the other of the first component and the second component; a controller including a processor and a non-transitory memory storing instructions executed by the processor to configure the controller, the controller comprising: receiving a first captured image from the camera when the second component is in a predetermined position relative to the first component; receiving a selection of a region of interest (ROI) of the first captured image including at least a portion of the first component and at least a portion of the second component; Identifying visible features of the second component within a region of interest of the first captured image; selecting a first point on the first component within a region of interest of the first captured image and a second point on the second component within a region of interest of the first captured image; receiving captured images from the camera during subsequent operation; monitoring the intensities of the first and second points in captured images received during subsequent operation; identifying a second captured image from the captured images received during the subsequent operation when the second component is expected to be at the predetermined position relative to the first component based on the monitored intensities of the first point and the second point in the captured image received during the subsequent operation; and a controller configured to determine whether the second component is in the predetermined position relative to the first component based on the second captured image and identified visible features of the second component within a region of interest of the first captured image.

2. the second component has a robotic arm that is movable relative to the first component; The system of claim 1 .

3. the first component has a wafer chamber, and the robot arm is configured to place a semiconductor wafer in the wafer chamber during the operation and the subsequent operation; The system of claim 2 .

4. The controller further comprises: determining first coordinates of identified visible features of the second component within a region of interest of the first captured image; storing the first coordinate in the non-transitory memory; Identifying visible features of the second component in the second captured image; configured to determine second coordinates of identified visible features of the second component within the second captured image; the controller is configured to determine whether the second component is at the predetermined position relative to the first component by comparing the second coordinates with the first coordinates. The system of claim 1 .

5. the controller is configured to determine that the second component is at the predetermined position relative to the first component when the second coordinate is equal to the first coordinate. The system of claim 4.

6. the controller is configured to determine that the second component is at the predetermined position relative to the first component when the second coordinate is within a predetermined threshold distance from the first coordinate. The system of claim 4.

7. the controller is configured to identify visible features of the second component in the first captured image and the second captured image based on intensity values ​​of pixels in the first captured image and the second captured image. The system of claim 4.

8. The controller is further configured to generate an alarm when the controller determines that the second component is not in the predetermined position relative to the first component. The system of claim 4.

9. the controller is configured to determine whether the second component is at the predetermined position relative to the first component during a predetermined step of the operation. The system of claim 4.

10. the controller is further configured to determine that the operation is at the predetermined step based on monitored intensities of the first point and the second point in the captured image during the subsequent operation remaining stable for a period of time. The system of claim 9.

11. A method for monitoring alignment of a second component relative to a first component by a computer device, comprising: capturing a first captured image when the second component is in position relative to the first component using a camera positioned in fixed relationship to the first component and operable to capture images of the first component and the second component during movement of the second component, one of the first component and the second component being darker than the other of the first component and the second component; receiving a selection of a region of interest (ROI) of the first captured image including at least a portion of the first component and at least a portion of the second component; identifying visible features of the second component within a region of interest of the first captured image; selecting a first point on the first component within a region of interest of the first captured image and a second point on the second component within a region of interest of the first captured image; receiving captured images from the camera during subsequent operation; monitoring the intensities of the first and second points in captured images received during subsequent operation; identifying a second captured image from the captured images received during the subsequent operation when the second component is expected to be at the predetermined position relative to the first component based on the monitored intensities of the first point and the second point in the captured image received during the subsequent operation; and determining whether the second component is at the predetermined position relative to the first component based on the second captured image and identified visible features of the second component within the region of interest of the first captured image.

12. the second component has a robotic arm that is movable relative to the first component; The method of claim 11.

13. the first component has a wafer chamber, and the robot arm is configured to place a semiconductor wafer in the wafer chamber during the operation and the subsequent operation; The method of claim 12.

14. determining first coordinates of identified visible features of the second component within a region of interest of the first captured image; storing the first coordinates in a memory; identifying visible features of the second component in the second captured image; determining second coordinates of the identified visible features of the second component within the second captured image; determining whether the second component is at the predetermined position relative to the first component includes determining whether the second component is at the predetermined position relative to the first component by comparing the second coordinates with the first coordinates. The method of claim 11.

15. determining whether the second component is at the predetermined position relative to the first component comprises determining that the second component is at the predetermined position relative to the first component when the second coordinate is equal to the first coordinate.

15. The method of claim 14.

16. determining whether the second component is at the predetermined position relative to the first component comprises determining that the second component is at the predetermined position relative to the first component when the second coordinate is within a predetermined threshold distance from the first coordinate.

15. The method of claim 14.

17. Identifying visible features of the second component in the first captured image includes identifying the visible features based on intensity values ​​of pixels in the first captured image; Identifying visible features of the second component in the second captured image includes identifying the visible features based on intensity values ​​of pixels in the second captured image.

15. The method of claim 14.

18. generating an alarm when it is determined that the second component is not in the predetermined position relative to the first component.

15. The method of claim 14.

19. determining whether the second component is in the predetermined position relative to the first component is performed during a predetermined step of the operation; 15. The method of claim 14.

20. The method further comprises determining that the operation is at the predetermined step based on monitored intensities of the first and second points in the captured image during the subsequent operation, which intensities remain stable for a certain period of time.

20. The method of claim 19.

Images