Substrate location detection and adjustment

Abstract

To provide systems and methods for positioning a wafer in relation to a datum structure such as an edge ring or chuck.SOLUTION: A system comprises a camera arrangement 200 of cameras 1, 2 including at least two cameras, each of the at least two cameras including fields 200', 200" of view when positioned in the camera arrangement, each field of view including a peripheral edge 204 of a wafer 206 and a peripheral edge 202 of a datum structure 210. A processor receives positional data from each of the at least two cameras and determines, in relation to each field of view, a gap size 208 between the respective peripheral edges of the wafer and the datum location included in the respective fields of view. A controller adjusts a position of the wafer relative to the datum structure, on the basis of the determined respective gap sizes.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] Claiming priority This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 802,932, entitled "Wafer Location Detection and Adjustment," by Martin et al., filed February 8, 2019, which is incorporated herein by reference in its entirety.

[0002] The present disclosure generally relates to detecting and adjusting a substrate (e.g., wafer) position using camera images on a process tool in semiconductor manufacturing. In some examples, systems and methods are provided for positioning a substrate relative to a datum structure, such as an edge ring or a chuck. [Background technology]

[0003] The background description provided herein is intended to provide a general overview of the contents of the present disclosure. Work by the currently named inventors within the scope of what is described in this Background section, as well as aspects of the description that may not otherwise be regarded as prior art at the time of filing, are not admitted, expressly or impliedly, as prior art against the present disclosure.

[0004] One method of centering the wafer on the edge ring or electrostatic chuck (ESC) relies on obtaining blanket etch rate and backside particle data with the wafer mounted at a "best guess" wafer center position. Blanket etch rates are obtained with the wafer at this position, and then post-etch measurements are performed on the blanket wafer to determine their deviation from center. Backside particle testing uses the backside particle imprint of the precoat on the ESC to determine the wafer offset relative to the ESC. This information can be used to adjust the calibration of the vacuum transfer module (VTM) robot to achieve wafer centering. This process is expensive and cumbersome, at least for blanket wafers due to their cost. Summary of the Invention

[0005] In some examples, a system for positioning a wafer relative to a datum structure is provided. An exemplary system includes a camera arrangement including at least two cameras, each of the at least two cameras including a field of view when positioned in the camera arrangement, each field of view including a peripheral edge of the wafer and a peripheral edge of the datum structure, a processor that receives position data from each of the at least two cameras and determines, in association with each field of view, a gap size between the peripheral edge of the wafer and each of the datum features included in the respective field of view, and a controller that adjusts a position of the wafer relative to the datum structure based on the determined respective gap sizes.

[0006] In some examples, the datum location includes an edge ring. In some examples, the datum location includes a chuck.

[0007] In some examples, the camera arrangement is mounted on a wall of the wafer processing chamber.

[0008] In some examples, the camera arrangement includes a third camera, which provides position data associated with a respective third field of view to the processor.

[0009] In some examples, each determined gap size is compared to a respective predefined gap size, with each predefined gap size being associated with a center or desired position of the wafer relative to a datum structure.

[0010] In some examples, the controller includes a vacuum transfer module (VTM) robotic arm.

[0011] In some examples, the processor identifies the center of the wafer based on the determined respective gap sizes.

[0012] In some examples, a system for positioning a wafer relative to a datum structure includes a camera arrangement including one or more cameras, each of which includes a field of view when positioned in the camera arrangement, each field of view including a peripheral edge of the wafer and a peripheral edge of the datum structure, a processor that receives position data from the or each camera and determines, in association with each field of view, a gap size between the peripheral edge of the wafer and each of the datum structures included in the respective field of view, and a controller that adjusts the position of the wafer relative to the datum structure based on the respective gap sizes determined.

[0013] In some examples, the one or more cameras include a single moveable camera.

[0014] In some examples, a single moveable camera is mounted on a robotic arm.

[0015] In some examples, the robotic arm is attached to a vacuum transfer module (VTM).

[0016] In some examples, the camera arrangement is mounted on a wall of the wafer processing chamber. [Brief description of the drawings]

[0017] Several embodiments are illustrated in the accompanying drawing figures by way of example and not by way of limitation.

[0018] [Figure 1] FIG. 1 is a schematic diagram of a reaction chamber in which some examples of the methods of the present disclosure may be used, according to some examples.

[0019] [Diagram 2] FIG. 2 is a diagram illustrating a camera configuration, according to some examples. [Diagram 3] FIG. 3 is a diagram illustrating camera configurations, according to some examples.

[0020] [Figure 4] FIG. 4 is a diagram illustrating a camera image, according to some examples. [Diagram 5] FIG. 5 is a diagram illustrating a camera image, according to some examples. [Figure 6] FIG. 6 is a diagram illustrating a camera image, according to some examples. [Figure 7] FIG. 7 is a diagram illustrating a camera image, according to some examples. [Figure 8] FIG. 8 is a diagram illustrating a camera image, according to some examples.

[0021] [Figure 9] FIG. 9 is a diagram illustrating a camera configuration, according to an example embodiment.

[0022] [Figure 10] FIG. 10 is a scatter plot, according to an example.

[0023] [Figure 11] FIG. 11 is a diagram illustrating operations in a method for centering a wafer, according to an example.

[0024] [Figure 12] FIG. 12 is a diagram illustrating a single camera configuration, according to an example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The following description includes systems, methods, and techniques that embody exemplary embodiments of the present invention. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the exemplary embodiments. However, it will be apparent to one skilled in the art that the subject matter of the present invention may be practiced without these specific details.

[0026] A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the patent document or patent disclosure being reproduced by anyone so long as the patent document or patent disclosure appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyrights. The following notice applies to the software and data described below or illustrated and forming a part of this document: Lam Research Corporation, 2018-2020, All Rights Reserved. The term "wafer" as used herein as an example is intended to include within its scope "substrate" more generally. Substrates can include photomasks, flat panel displays, and the like, which may also be processed with the systems and methods described herein.

[0027] An exemplary chamber in which some examples of the present disclosure may be used with appropriate chamber modifications for film deposition and control testing is shown in FIG. 1 of the accompanying drawings. A typical plasma etching (or deposition) apparatus comprises a reactor in which there is a chamber through which one or more reactive gases flow. In the chamber, the gases are ionized into a plasma, typically by radio frequency energy. The highly reactive ions of the plasma gases can react with materials, such as polymer masks, on the surface of a semiconductor wafer to be processed into an integrated circuit (IC). Prior to etching, the wafer is loaded into the chamber and held in place by a chuck or holder that exposes the top surface of the wafer to the plasma gases. There are several types of chucks known in the art. The chuck provides an isothermal surface and acts as a heat sink for the wafer. In one type, the semiconductor wafer is held in place for etching by mechanical clamping means. In another type of chuck, the semiconductor wafer is held in place by electrostatic forces generated by an electric field between the chuck and the wafer. The method of the present invention is applicable to both types of chucks.

[0028] FIGURE 1 illustrates a capacitively coupled plasma processing chamber 100, which represents an exemplary plasma processing chamber of the type typically used to etch substrates. Referring now to FIGURE 1, chuck 102 represents a workpiece holder upon which a substrate, such as a wafer 104, is positioned during etching. Chuck 102 may be implemented by any suitable chucking technique (e.g., electrostatic, mechanical, clamp, vacuum, etc.). During etching, chuck 102 is typically simultaneously supplied with dual RF frequencies (low and high frequency), e.g., 2 MHz and 27 MHz, by dual frequency source 106.

[0029] A vacuum transfer module (VTM) (not shown) can be used to place and center (or position) the wafer 104 on the chuck 102. Accurate wafer positioning or centering is typically a critical aspect in successfully performing certain processing operations on the wafer 104 in the processing chamber 100. These operations may include, for example, deposition, etching, and edge bevel removal (EBR). Other operations are also possible. In some examples, the VTM includes one or more robotic controls or arms for manipulating the wafer 104 as it is placed on the chuck 102. In examples of the present disclosure, the VTM robotic arms are guided during wafer placement and centering by an array of cameras and feedback or other data generated by a VTM control module, which is described further below. One or more components of the processing chamber 100 can be used as datum points in determining the location or center of the wafer 104. In some examples, the proximity of one or more locations at the peripheral edge of the wafer 104 to processing chamber components is used in determining the wafer center. In some examples, two or three peripheral edge locations may be used for the wafer 104. In some examples, the datum feature includes an edge ring 118.

[0030] Referring again to Figure 1, an upper electrode 108 is positioned above the wafer 104. The upper electrode 108 is grounded. Figure 1 shows an etching reactor in which the surface of the upper electrode 108 is larger than the surface of the chuck 102 and the wafer 104. During etching, a plasma 110 is formed from an etchant gas supplied via gas line 112 and exhausted through exhaust line 114. An electrically insulating ring 109 insulates the upper electrode 108 from the processing chamber 100.

[0031] A confinement ring 116 may be disposed between the upper electrode 108 and a lower electrode, such as the chuck 102 of Figure 1. In general, the confinement ring 116 helps confine the etching plasma 110 to an area above the wafer 104 to improve process control and ensure repeatability.

[0032] When RF power is supplied from the dual frequency source 106 to the chuck 102, equipotential field lines are set up on the wafer 104. The equipotential field lines are electric field lines across the plasma sheath between the wafer 104 and the plasma 110. In some instances, the equipotential surfaces and the electric field lines are perpendicular to each other. Equipotential surfaces exist between the wafer 104 and the plasma 110. The electric field lines accelerate charged particles across these equipotential surfaces. During plasma processing, positive ions accelerate across the equipotential field lines to impact the surface of the wafer 104, thereby providing desired etching effects, such as improved etch directionality. Due to the geometry of the upper electrode 108 and the chuck 102, the electric field lines are not uniform across the wafer surface and may be significantly different at the edge of the wafer 104. Thus, an edge (or focus) ring 118 is typically provided to improve process uniformity across the wafer surface. 1, the wafer 104 is shown disposed within an edge ring 118, which may be formed of a suitable dielectric material such as ceramic, quartz, plastic, etc. The presence of the edge ring 118 thus allows the equipotential field lines to be disposed substantially uniformly across the surface of the wafer 104.

[0033] A conductive shield 120 substantially surrounds the edge ring 118. The conductive shield 120 is configured to be substantially grounded within the processing chamber 100. The conductive shield 120 prevents the presence of unwanted equipotential field lines outside of the edge ring 118.

[0034] As explained above, there can be significant challenges associated with the use of blanket wafers in wafer centering operations. Examples of the present disclosure do not require blanket wafer images, but instead use images captured by a camera mounted above the wafer 104 to measure and guide the wafer centering operations. The wafer centering operations can be performed relative to a datum structure or component within a process module, such as the edge ring 118, or a chuck 102, such as an electrostatic chuck (ESC). In some examples, the position data is sent as feedback to a wafer transfer module (e.g., VTM) to adjust its calibration until the wafer 104 is properly centered on the chuck 102.

[0035] An example of the present disclosure performs in-situ measurements of the wafer 104 during a wafer centering operation and provides immediate feedback to a controller user interface (UI) of a control module. With the wafer 104 resting on the chuck 102 in the processing chamber 100, an array of one or more measurement cameras takes images that may include one or more locations or portions of the outer circumferential edge of the wafer 104 and at least one inner edge of the edge ring 118. Image processing software identifies the wafer periphery and the inner edge of the edge ring 118 and calculates the separation distance, or gap, between them. In some examples, this measurement is performed at several points around the periphery of the wafer 104. The measurement results are then used to adjust the VTM robot control for placing the wafer 104 on the chuck 102 in the processing chamber 100. By repeating the above procedure, the progress of the wafer centering operation can be quickly checked.

[0036] Referring to FIG. 2, a configuration 200 of one or more cameras (e.g., camera 1 and camera 2) associated with the processing chamber 100 can capture images and perform image measurements. In some examples, cameras 1 and 2 each have a respective field of view 200′ and 200″ capable of detecting an inner edge 202 of an edge ring 210 and a peripheral edge 204 of a wafer 206. A separation distance or gap 208 between the inner edge 202 and the peripheral edge 204 of the edge ring 210 can be detected and measured by cameras 1 and 2. A convenient exemplary configuration for performing the measurement of the gap 208 includes providing a vacuum-sealed window in a wall of the processing chamber 100 and positioning cameras 1 and 2 in the window. In some examples, the image capture and gap measurement are performed during start-up and maintenance phases of the processing chamber 100. In other examples, cameras 1 and 2 are mounted on a robotic arm of a vacuum transfer module (VTM) to facilitate centering and gap measurements performed under the control of an operator of the processing chamber 100. In some examples, illumination is controlled during gap image measurements.

[0037] Although the configuration 200 of FIG. 2 includes two cameras, other configurations are possible. For example, a single movable camera can be placed at two different locations to obtain respective fields of view 200' and 200''. In yet another exemplary configuration 1200 shown in FIG. 12, a single movable camera can be moved between locations 1202, 1204, and 1206 to obtain or generate one or more respective fields of view 1200', 1200'', and 1200'''' at those camera locations. Some or all of the cameras in the various examples described herein can be fixed or movable. Some examples can include or generate a composite field of view, e.g., a single field of view captured by a single camera that includes or encompasses multiple sub-views. Exemplary sub-views can include those at locations 1202, 1204, and 1206 of FIG. 12. Other combinations of fields of view and camera configurations are also possible.

[0038] An alternative camera configuration 300 is shown in FIG. 3. The illustrated configuration includes three cameras 1, 2, and 3 (labeled 302, 304, and 306 in the figure) positioned to capture images looking down on an edge ring 310 and wafer 312 disposed in a processing chamber, such as processing chamber 100 of FIG. 1. Each camera 1, 2, and 3 has a respective field of view 300', 300'', and 300'''. A VTM 308 (not shown to scale) may be located adjacent to the processing chamber 100 being monitored. In some examples, a single VTM 308 has a rectangular footprint spanning an area large enough to service multiple adjacent processing chambers 100. In some examples, a single VTM 308 has five processing chambers 100 positioned along each side of it. The VTM 308 (FIG. 3) may include a robotic arm 310 (not shown to scale) for manipulating one or more cameras between the respective fields of view 302, 304, and 306. A single camera or multiple cameras may be mounted on the VTM arm 310 so that field of view or gap measurements can be established or made at the discretion of an operator or by an automated processor. In some examples, illumination of the field of view is controlled, for example, while making gap measurements or when monitoring the field of view. Although the configuration of FIG. 3 includes three cameras 1-3, a single moving camera or multiple stationary cameras may be used to make such measurements.

[0039] FIG. 4 shows exemplary images 402 and 404 of photographs captured by cameras 1 and 2 of various embodiments described herein. The image 402 on the left illustrates a relatively small gap 406 between the inner edge 202 of the edge ring 210 and the peripheral edge 204 of the wafer 206. Thus, camera 1 detects that the wafer is placed relatively close to the edge ring 210. The image 404 on the right illustrates a larger gap 408 between the inner edge 202 of the edge ring 210 and the peripheral edge 204 of the wafer 206. Camera 2 detects that the wafer is placed further away from the edge ring 210. In some examples, the wafer-to-edge ring gap 208 in FIG. 2 (or 406 and 408 in FIG. 4) can be adjusted or set based on different VTM robot settings. A bare silicon (Si) wafer 206 (for example) can be used, although other types of wafers 206 are possible. Other examples may include the use of a calibration wafer having markings indicating a reference angle and / or wafer radius, which in some examples may be provided in distinguishing colors within images 402 and 404. Information (position data) regarding gaps 406 and 408 may be dynamically transmitted as feedback to VTM 308 during wafer centering operations. Based on the feedback received, the wafer position may be adjusted in steps or continuously until a preset or predetermined gap value for the wafer center position is established.

[0040] 5-8 show respective exemplary images (e.g., in fields of view 300′, 300″, and 300′″ taken by cameras 1, 2, and 3 of FIG. 3) of the peripheral edge 204 of a wafer 502 corresponding to the position of each camera next to the associated inner edge 202 of the edge ring 210. The wafer 502 is positioned on a chuck 102 in a processing chamber 100. It will be understood that while the peripheral edges of the wafer 502 are represented by straight lines, in reality, they are slightly arcuate. The position of a VTM 512 adjacent to the processing chamber 100 is shown in FIG. 5. The VTM 512 is similarly positioned in each of the views of FIGS. 6-8. In the view 500 of FIG. 5, the initial positions or datum positions 504, 506, and 508 of the top, bottom, and right edges of the wafer 502, respectively, are shown in FIG. 5. A separation distance or top gap 510 (for purposes of this example) may be correspondingly derived and recorded.

[0041] The image in Figure 6 represents movement of the wafer under control of the robot arm of VTM 512 away from the location of VTM 512 (Figure 5) in direction 602. The top gap 510 has correspondingly widened.

[0042] 7 image depicts movement of the wafer back to the initial or datum wafer position 702 towards the VTM 512. The size of the top gap 510 has been correspondingly restored.

[0043] For further purposes of this example, an initial side gap 704 (FIG. 7) may be derived and recorded. The image in FIG. 8 represents movement of the wafer under control of the robot arm of VTM 512 in a direction 802 to the right. The side gap 704 correspondingly narrows. Position data representative of such wafer movement, derived from the top and side gap images captured by the array of cameras 1, 2, and 3, is dynamically transmitted back to the control module of VTM 512 to facilitate locating and centering the wafer 502 during wafer placement and centering operations.

[0044] Referring to FIG. 9, a configuration 900 of a wafer 206 and edge ring 210 is shown. Using the edge ring 210 as a datum, the center of the wafer 206 of known diameter (and therefore known radius) can be determined based on measurements of the top gap 510 and side gap 704, or based on the locations relative to the gaps 510 and 704. Based on images taken by cameras 1 and 2 shown in the figure, a separation distance or top gap 510 between a location X on the peripheral edge 204 of the wafer 206 and an adjacent location X' on the inner edge 202 of the edge ring 210 can be determined. The separation distance or side gap 704 can be determined in a similar manner for locations Y and Y'. For simplicity, cameras 1 and 2 are shown in the right and bottom quadrant camera positions as shown in the figure, rather than their actual locations in the top and left quadrants where images of the top gap 510 and side gap 704 are actually taken.

[0045] In some examples, the location of points X' and Y' may be known or may be derived based on, for example, a known location or dimension of edge ring 210, which may serve as a datum component in this regard. A center 908 of edge ring 210 may correspondingly be established as a reference for wafer centering and processing purposes.

[0046] Using the known locations of points X' and Y', the top and side gaps 510 and 704, respectively, can be applied to determine the locations of points X and Y on the peripheral edge 204 of the wafer 206. The radius of the wafer 206 is known, and a notional circumference (or an arc portion of a circumference) based on the wafer radius can be circumscribed around each point X and Y accordingly. The notional circumferences of point X are labeled 902 and 904, respectively, with respect to point Y. The intersection of the notional circumferences 902 and 904 within the perimeter of the wafer 206 establishes the center of the wafer 206 at center 910. Since it is understood that the center of the wafer 206 falls within its perimeter, the intersection of the circumferences 902 and 904 (at point 906) outside the perimeter of the wafer 206 can be discarded as an invalid result. The determined center 910 of the wafer 206 can be compared to the true center 908 of the edge ring 210 on a dynamic basis to derive offset or position data 912.

[0047] In some examples, feedback based on the offset data is provided to a control module of the VTM 512 to adjust the position or path of the wafer 206 during wafer centering. During a wafer centering operation, position adjustments to the wafer 206 may be made by the control module of the VTM 512 based on a determination of the top and side gaps 510 and 704, or a determination of the positions of the edge ring 210 and wafer centers 908 and 910, or based on a combination of both sets of data or portions thereof.

[0048] FIG. 10 illustrates a scatter plot 1000 showing measured variations in wafer center obtained by camera measurements (solid ring dots 1002) and VTM robot setpoint commands (dashed ring dots 1004). Lines 1006 and 1008 link the measured wafer center 1002 to its associated robot setpoint 1004. The shorter line segment 1008, shown with a solid outline, indicates that each measured wafer center 1002 is within the VTM robot wafer setpoint 1004 specifications. This reflects the robot repeatability specifications discussed above. The longer line segment 1006 indicates that the measured wafer center 1002 is within, for example, 133% of the VTM robot specifications. Other margins of accuracy may be used. The hash line 1010 indicates a single wafer measurement that exceeds, for example, 133% of the robot setpoint. The dotted line 1012 indicates a camera measurement that correctly captures, for example, robot placement errors. Other metrics are also possible.

[0049] Thus, in some examples, a method for centering a wafer is provided. Referring to Figure 11, a method 1100 for centering a wafer relative to a datum structure includes, in operation 1102, mounting a camera arrangement including at least two cameras adjacent to a wafer processing chamber, each of the at least two cameras including a field of view when positioned in the camera arrangement, each field of view including a peripheral edge of the wafer and a peripheral edge of the datum structure, in 1104, receiving position data from each of the at least two cameras and determining, in association with each field of view, a gap size between the respective peripheral edges of the wafer and the datum structure included in the respective field of view, and in 1106, adjusting a position of the wafer relative to the datum structure based on the determined respective gap sizes.

[0050] In some examples, the datum location includes an edge ring. In some examples, the datum location includes a chuck.

[0051] In some examples, the method 1100 further includes providing a camera arrangement on a wall of the wafer processing chamber.

[0052] In some examples, the method 1100 further includes including a third camera in the camera arrangement and providing position data from the third camera to the processor associated with the respective third field of view.

[0053] In some examples, the method 1100 further includes comparing each determined gap size to a respective predetermined gap size, each predetermined gap size associated with a center position or a desired position of the wafer relative to a datum structure or the wafer processing chamber.

[0054] In some examples, the method 1100 further includes including in the controller a vacuum transfer module (VTM) robotic arm.

[0055] Thus, embodiments are provided for camera-based image sensing to position the wafer position relative to the edge ring 210 in the processing chamber 100. Examples of the present disclosure may provide improved speed, cost, and accuracy. Some examples may facilitate performing quick in-situ measurements during wafer positioning or centering operations. Typically, blanket wafers are etched in a process module and metrology is performed on the wafer 206 to determine wafer centering. In a fab, where the wafer 206 is typically tracked, pre-measured, and moved, traditional metrology operations may take a given period of time to complete. On the other hand, the process of the present invention can reduce that time by a factor of eight. In a lab process tool, using the methods disclosed herein, performing these operations may take as little as 12.5% ​​of the traditional time required in a fab.

[0056] Conventional methods of wafer centering typically take a long time to complete and often use blanket wafers. Some exemplary methods herein require only a one-time cost. The camera measurements of the present disclosure can, in some examples, determine wafer placement within the specifications of the VTM robot control setpoints in most cases. In all but one example in FIG. 10, the camera measurements determined wafer placement within the specifications of conventional backside particle metrology. The embodiments can be configured or tuned as needed with modifications to both the hardware and image processing algorithms.

[0057] Although the embodiments have been described with reference to certain exemplary embodiments, it will be apparent that various modifications and changes can be made thereto without departing from the broader scope of the embodiments. Thus, the specification and drawings should be considered in an illustrative and not a restrictive sense. The accompanying drawings, which form a part of this specification, show, by way of example and not of limitation, specific embodiments in which the subject matter may be practiced. The illustrated embodiments are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and other embodiments may be derived from the teachings disclosed in the specification, such that structural and logical substitutions and changes can be made without departing from the scope of the present disclosure. Thus, this detailed description is not to be construed in a limiting sense, and the scope of the various embodiments is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled.

[0058] Such embodiments of the inventive subject matter may be individually and / or collectively referred to herein by the term "invention", but this is merely a matter of convenience and is not intended to voluntarily limit the scope of this application to any single invention or inventive concept (if in fact more than one is disclosed). Thus, although specific embodiments have been illustrated and described herein, it should be understood that any configuration calculated to achieve the same purpose may be substituted for the specific embodiment shown. The present disclosure is intended to cover any and all adaptations or modifications of the various embodiments. Combinations of the above embodiments with other embodiments not specifically described herein will be apparent to one of skill in the art upon reviewing the above description.

Claims

1. 1. A system for positioning a wafer relative to a datum structure, comprising: a camera arrangement including at least two cameras, each of the at least two cameras including a field of view when positioned in the camera arrangement, each field of view including a peripheral edge of the wafer and a peripheral edge of the datum structure; a processor that receives position data from each of the at least two cameras and determines, associated with each field of view, a gap size between the respective peripheral edge of the wafer and a datum location included in the respective field of view; a controller that adjusts a position of the wafer relative to the datum structure based on the determined respective gap sizes; A system comprising:

2. 2. The system of claim 1, The datum location includes an edge ring.

3. 2. The system of claim 1, The datum location includes a chuck.

4. 2. The system of claim 1, The system wherein the camera arrangement is mounted on a wall of a wafer processing chamber.

5. 2. The system of claim 1, The system, wherein the camera arrangement includes a third camera, the third camera providing position data associated with a respective third field of view to the processor.

6. 2. The system of claim 1, The system further comprising: a step of comparing each of the determined gap sizes to a respective predetermined gap size, the respective predetermined gap size being associated with a center position or a desired position of the wafer relative to the datum structure.

7. 2. The system of claim 1, The controller includes a vacuum transfer module (VTM) robotic arm.

8. 2. The system of claim 1, The processor identifies a center of the wafer based on the determined respective gap sizes.

9. 1. A method for positioning a wafer relative to a datum structure, comprising: mounting a camera arrangement adjacent to a wafer processing chamber, the camera arrangement including at least two cameras, each of the at least two cameras including a field of view when positioned in the camera arrangement, each field of view including a peripheral edge of the wafer and a peripheral edge of the datum structure; receiving position data from each of the at least two cameras and determining, associated with each field of view, a gap size between the respective peripheral edge of the wafer and a datum location included in the respective field of view; adjusting a position of the wafer relative to the datum structure based on the determined respective gap sizes; A method comprising:

10. 10. The method of claim 9, The datum feature includes an edge ring.

11. 10. The method of claim 9, The datum location includes a chuck.

12. 10. The method of claim 9, The method further comprising providing the camera arrangement on a wall of the wafer processing chamber.

13. 10. The method of claim 9, The method of claim 1, further comprising including a third camera in the camera arrangement and providing position data from the third camera to the processor associated with a respective third field of view.

14. 10. The method of claim 9, The method further includes comparing each determined gap size to a respective predetermined gap size, wherein each predetermined gap size is associated with a center or desired position of the wafer relative to the datum structure or the wafer processing chamber.

15. 10. The method of claim 9, The method further comprising having the controller include a vacuum transfer module (VTM) robotic arm.

16. 1. A system for positioning a wafer relative to a datum structure, comprising: a camera arrangement including one or more cameras, each of the one or more cameras including a field of view when positioned in the camera arrangement, each field of view including a peripheral edge of the wafer and a peripheral edge of the datum structure; a processor for receiving position data from the or each camera and for determining, associated with each field of view, a gap size between the respective peripheral edge of the wafer and a datum location included in the respective field of view; a controller that adjusts a position of the wafer relative to the datum structure based on the determined respective gap sizes; A system comprising:

17. 17. The system of claim 16, The one or more cameras include a single moveable camera.

18. 20. The system of claim 17, The system wherein the single moveable camera is mounted on a robotic arm.

19. 20. The system of claim 18, The system wherein the robotic arm is attached to a vacuum transfer module (VTM).

20. 17. The system of claim 16, The system wherein the camera arrangement is mounted on a wall of a wafer processing chamber.

Images