Deposition device and method of imaging a feature on a substrate

Abstract

This invention describes a deposition apparatus. The deposition apparatus includes a substrate support and an imaging system configured to image a portion of a substrate positioned on the substrate support. The imaging system includes an LED light source and an imaging unit, and is coupled to a deposition assembly disposed across the substrate support.

Description

[Technical Field]

[0002] Cross-reference to related applications: This application claims the benefit of U.S. Provisional Patent Application No. 63 / 198,555, filed on October 27, 2021, which is incorporated herein by reference in its entirety.

[0003] Specific examples of the present invention generally relate to deposition apparatuses. Specifically, a deposition apparatus having an attached but movable service platform is described. [Previous Technology]

[0004] Inkjet deposition is common in office and home printers, as well as in industrial-scale printers used for manufacturing displays, depositing large-scale writing materials, adding materials to products such as printed circuit boards, and constructing biological articles such as tissues. Most commercial and industrial inkjet deposition machines, and some consumer printers, use a dispenser to apply material to a substrate. The dispenser sprays a controlled amount of deposited material toward the substrate at a controlled time and a controlled rate, so that the deposited material reaches the substrate and is positioned at the target location, forming a mark of the desired size and shape.

[0005] In some situations, such as in the display manufacturing industry, extremely high-precision deposition is achieved by depositing extremely small volumes of material at extremely precise locations. In some cases, these volumes can be as small as 10 μm and deposited in areas with a size of 15 μm. To achieve this precision when placing the material on the substrate, the substrate must be precisely positioned and / or its position must be precisely known. Camera vision systems are conventionally used to photograph the substrate and accurately determine its position, but capturing and processing images is time-consuming. A better method is needed to accurately determine the position of the substrate used for inkjet printing. [Summary of the Invention]

[0006] The specific examples described herein provide a deposition apparatus comprising: a substrate support; and a deposition assembly including an imaging system disposed across the substrate support, the imaging system including an LED light source.

[0007] Other specific examples described herein provide a method for imaging a feature on a substrate, comprising: scanning the substrate relative to an imaging system comprising an LED light source and an imaging unit; activating the imaging unit before an end of the feature reaches an illumination field of the LED light source; activating the LED light source when a portion of the feature reaches the illumination field; deactivating the LED light source after an effective time; and deactivating the imaging unit after an imaging time, wherein the imaging time covers the effective time.

[0008] Other specific examples described herein provide a deposition apparatus comprising: a substrate support; and a deposition assembly including an imaging system disposed across the substrate support, the imaging system comprising: an LED light source optically coupled to an optical component to direct radiation from the LED light source to the substrate support; and an imaging unit disposed to capture radiation reflected through the optical component.

Implementation Method

[0017] This document describes a deposition apparatus having a service platform that can be deployed above a working surface of the deposition apparatus and stacked adjacent to the end of the working surface at a height at least partially below the base height of the working surface to allow for substrate loading and unloading. Figure 1 is an isometric top view of a deposition apparatus 100 according to a specific example. The deposition apparatus has a substrate support 102, a deposition assembly 104, and a holder assembly 106 for manipulating the substrate for deposition. The deposition apparatus 100 includes a base 108, which is typically a large object to minimize vibration transmission to the operating components of the deposition apparatus 100. In one example, the base 108 is a granite block. The deposition assembly 104 includes a deposition assembly support 116, which includes brackets 120 on each side of the base 108 and guide rails or beams 117 extending across the substrate support 102 between the brackets 120.

[0018] The substrate support 102 has a first section 102A, a second section 102B, and a third section 102C between the first section 102A and the second section 102B. The first section 102A and the second section 102B are segmented regions for the substrate to enter and exit the deposition apparatus 100, while the third section 102C is a working section for positioning the substrate to be processed relative to the deposition assembly support 116. The substrate support 102 has a working surface 110 and a member for making the working surface 110 substantially frictionless. Here, the working surface 110 is an air cushion stage that provides an air cushion, such as air, oxygen-deficient air, dry air, nitrogen, or other suitable gas on which the substrate floats. The working surface 110 is characterized by a plurality of holes (not shown) that allow gas jets to exit, thus providing an upward force to hold the substrate at a desired height above the working surface 110. Some of these holes also allow for controlled extraction of gas from the self-floating air cushion, providing precise local control over the substrate height. In one specific example, the third section 102C has both supply and extraction ports. The supply and extraction ports provide independent control over the gas in the air cushion and thus independent control over the substrate's floating height above the substrate working surface 110.

[0019] The deposition assembly 104 includes a distributor assembly 114 coupled to a crossbeam 117. The distributor assembly 114 includes a distributor housing 119 coupled to a deposition carrier 122 that travels along the crossbeam 117 to position the distributor assembly 114 relative to a substrate disposed on a third segment 102C of a substrate support 102. The distributor housing 119 contains one or more distributors (not shown) that spray a volume of deposition material onto the substrate positioned on the substrate support 102 below the deposition assembly 104.

[0020] In operation, the substrate is positioned below the deposition assembly 104 by means of the holder assembly 106. The holder assembly 106, after loading, achieves firm contact with the substrate and moves the substrate along the substrate support 102 to position the substrate relative to the deposition assembly 104, thereby precisely dispensing printing material onto the substrate. In this configuration, the holder assembly 106 extends substantially along the substrate support 102 in a first direction to transfer the substrate in that first direction during deposition. The first direction is indicated by arrow 124 in FIG. 1. The dispenser assembly 114 moves substantially in a second direction, substantially perpendicular to the first direction, defined by a crossbeam 117 extending substantially in the second direction, and indicated by arrow 126 in FIG. 1. The second direction 126 is sometimes referred to as the "x-direction," and the crossbeam 117 is referred to as the "x-beam."

[0021] Controller 132 is operatively coupled to holder assembly 106 and deposition assembly 104 to control the movement of a substrate positioned on a substrate support and the deposition on that substrate. Controller 132 may directly control the actuators of holder assembly 106 and deposition assembly 104, or controller 132 may be operatively coupled to a holder assembly controller coupled to holder assembly 106 and a deposition assembly controller coupled to deposition assembly 104. Controller 132 controls the movement and positioning of the substrate (if present) on substrate support 102. Controller 132 also controls the movement of dispenser assembly 114 along beam 117 and the spraying of deposition material from dispenser assembly 114 onto the substrate.

[0022] Imaging system 150 is coupled to distributor assembly 114. Imaging system 150 includes LED light source 152 and imaging unit 154. LED light source 152 directs radiation onto a substrate positioned on substrate support 102 located below distributor assembly 114. Imaging unit 154 detects illumination radiation reflected from the substrate. Imaging unit 154 may include a digital camera or other high-precision image capture component. Imaging unit also includes optics for focusing radiation into image capture component. LED light source 152 and imaging unit are configured such that LED light source 152 provides an illumination field on substrate within the imaging field of imaging unit 154.

[0023] The LED light source 152 can emit radiation selected to minimize its impact on other aspects of the deposition apparatus 100 and the procedures performed by the deposition apparatus 100. For example, in many cases, the deposition apparatus 100 is used to deposit curable materials onto a substrate. Such materials are conventionally cured using short-wavelength electromagnetic radiation such as ultraviolet radiation. These materials are also frequency-sensitive to short-wavelength visible light radiation and can have lower sensitivity to longer-wavelength visible light radiation. Because uniform processing is crucial for achieving high-precision results in industries such as display manufacturing, the LED light source can be selected to emit long-wavelength radiation to minimize any impact on the deposited material. In this regard, a light source with an emission wavelength of 650 nm or greater is useful. In one example, the light source has an emission wavelength of 650 nm. In another example, the light source has an emission wavelength of 800 nm.

[0024] The LED source can be an array of LEDs selected to provide the desired illumination field, which enables the imaging system to capture an image in a very short time. Imaging in a very short time allows for the capture of a clear image of an area of ​​a moving substrate. The combination of the light source and the image capture component can also be selected to maximize the sensitivity of the image capture component to radiation emitted by the LED light source. For example, the Dalsa Nano M2020 camera has near-peak sensitivity at a wavelength of 650 nm. Silicon-based NIR image capture units typically have peak sensitivity around 800 nm. LED light sources whose emission spectra peak at or near these wavelengths can be used.

[0025] The LED light source 152 can be fiber-coupled to transfer LED light emission to an emitting plane that can be positioned close to the substrate. Using an LED light source provides high luminous intensity and rapid switching from peak luminous intensity without the need for decorrelation processing of the laser light. For many display applications, the substrate has positioning features, such as reference marks, that can be used to accurately calibrate the substrate's position. The marks can be small, for example, 0.5 mm to 5 mm in size. In some cases, the marks have a cross shape. Fiber coupling allows the radiating emitting plane to be positioned such that the radiation produces a uniform bright spot covering all or a substantial portion of the field of view required to determine the mark's position.

[0026] The imaging system 150 is configured to capture images as the substrate and the distributor assembly 114 move relative to each other. In some cases, this relative movement can be as fast as 1 m / sec. An imaging controller 158 is operatively coupled to the LED light source 152 and the image capture unit 154 to drive image capture during the relative movement. Here, the LED light source has a pulse capability of at least a few µsec, meaning that the average intensity of the emitted radiation field increases during the pulse duration, reaches half of its maximum value at the start of the pulse, decreases, and reaches half of its maximum value at the end of the pulse. This pulse duration is defined as the duration from the start of the pulse to the end of the pulse, which in some cases is a few µsec or even less than 1 µsec. The imaging controller 158 is implemented in a printed circuit board containing digital circuitry that transmits commands to the image capture unit 154 to start and stop image capture, and to a power supply or a switch electrically coupled between the power supply and the LED light source 152 to turn on and off, or alternatively to emit pulses with a defined duration. Imaging controller 158 is operatively coupled to controller 132 and, where appropriate, to other controllers such as holder assembly controller and distributor assembly controller to send and receive signals representing information for controlling the imaging of the substrate. Imaging controller 158 is configured to send signals representing images captured by imaging capture unit 154 to controller 132 for analysis. Imaging controller 158 is also configured to control image capture unit 154 and LED light source 152 to capture images when substrate features (such as positioning features) are expected to be within the field of view of image capture unit 154, based on information received from controller 132 (such as the expected position of features and the rate of movement of the substrate).

[0027] The LED light source is electrically coupled to a power supply configured to provide voltage to the LED light source, which causes the desired luminous intensity for imaging during the duration described above. Multiple LED emitters in the LED light source can be selected to provide total lumens for capturing clear images during the short duration described above. In one example, the LED array may be an array of 24 LEDs emitting at a wavelength between 610 nm and 650 nm, each LED having a luminous output of approximately 65 lumens at an applied voltage of approximately 1.8 V. LEDs that can be used include the LUXEON® Star LXZ1-PH01 LED, available from Lumileds, San Jose, California. In one case, 40 of these LEDs are assembled into a 5×8 array. In another case, 24 of these LEDs are assembled into a 4×6 array. In yet another case, 40 LEDs can be assembled into a circular profile. In still another case, more LEDs can be used. For example, in one case, 50 LEDs can be used as the light source.

[0028] Figure 2 is a front view of a position acquisition system 200 according to a specific example. The position acquisition system 200 includes an imaging system 150 and a substrate 202 mounted on a substrate support 102 for processing. The imaging system 150 is operatively coupled to an imaging controller 158, which is further operatively coupled to a system controller 132, as described above. The imaging system 150 is also operatively coupled to a positioning controller 204, which controls and adjusts the position of the imaging system 150. The positioning controller 204 can adjust the position of the imaging system 150 relative to the dispenser of the dispenser housing 119 of Figure 1.

[0029] In this configuration, the imaging system 150 includes an LED light source 206 and an imaging unit 208. An optical assembly 210 optically couples the LED light source 206 and the imaging unit 208 to a substrate 202 for imaging. The optical assembly may include one or more lenses, prisms, optical fibers, and / or mirrors for guiding and / or focusing light reflected from the substrate into the imaging unit 208. An optical fiber 212 transfers radiation emitted by the LED light source 206 to an emission point 214, which may be located at an end of the optical assembly 210 away from the substrate support 102, extend beyond the end of the optical assembly 210 to a position closer to the substrate support 102 than the end of the optical assembly 210, or be recessed within the optical assembly 210. The optical fiber 212 is supported by a support 216 that maintains the position of the emission point 214. Radiation is emitted from the optical fiber 212 at the emission point 214 and traverses the gap between the emission point 214 and the substrate 202 to provide an illumination field 218. The size of the illumination field 218 can be controlled by controlling the position of the emission point 214 relative to the substrate 202. During processing, the substrate is typically scanned relative to the imaging system 150 to illuminate a portion of the substrate to be imaged, as schematically indicated by arrow 220. The LED light source 206 is activated when a portion of the substrate to be imaged is partially or completely within the illumination field 218 during relative scanning, and deactivated when the portion to be imaged has traversed the illumination field 218 for a time sufficient to capture the desired image of the entire area to be imaged. This can be when the first portion of the area to be imaged leaves the illumination field 218, or when the last portion of the area to be imaged leaves the illumination field 218. The LED light source 206 can be activated by closing a switch electrically coupled between a power supply (not shown) and the LED light source 206. The switch can be controlled by a signal sent from the controller 123 (FIG. 1) or by a local controller for the LED light source 206, or a combination thereof.

[0030] Figure 3 is an algorithm diagram of an image capture control algorithm 300 according to a specific example. The image capture control algorithm 300 is used with a deposition apparatus such as device 100. The image capture control algorithm 300 generates triggers for initiating image capture of features on substrate 301 by means of an image capture unit and for initiating illumination by an illumination unit. The illumination unit is capable of generating short pulses with uniform radiation within the illumination field. The duration of the pulse is approximately 1 µsec or less, enabling the capture of images of small features on the substrate at a relative motion rate of up to 1 m / sec. An LED light source can be used, such as an LED source array having an emission wavelength matching the spectral sensitivity of the image capture unit and sufficient light output to enable the capture of clear images during the short exposure duration described above.

[0031] Algorithm 300 uses position markers and position signals from the substrate holder to determine when image capture by the image capture unit begins and when illumination by the illumination source begins. Typically, the algorithm uses a defined coordinate system used by the controller to execute algorithm 300. The substrate has a defined origin 302, which is located at a known position (xs, ys) relative to the original position 304 (xH, yH) of the holder, which is also known. The designed position 306 (xF, yF) of the feature on the substrate is known relative to the substrate origin 302. In a specific instance where the substrate moves in the y-direction during processing, the y-positions of the holder, the substrate origin, and the feature are yh, ys, and yf, respectively. These y-positions of the holder, the substrate origin, and the feature are offset by the same distance 308 from their respective original positions in the y-direction. If the imaging system moves during processing, the position of the illumination field 310 at any given time is yi. The feature has designed dimensions of ΔxF and ΔyF. The illumination field 310 generated by the imaging system has a known position (xI, yI) relative to the original position of the holder. The illumination field also has dimensions ΔxI and ΔyI. Therefore, in the y-direction, the illumination field extends from xI to yI, or if the imaging system moves, the illumination field extends from xI to yI. At any time during the procedure, the holder's y-position yh is known from the actuator position.

[0032] Various location markers are provided to a controller, such as controller 132. The algorithm determines when to activate the image capture unit and the illumination source to capture an image of the feature based on the expected location of the feature. The size of the illumination field is set to provide sufficient coverage such that any offset between the expected location of the feature and the actual location of the feature is less than the amount required to keep the feature entirely within the illumination field during exposure.

[0033] Assume the relative moving speed of the substrate and the imaging system in the y-direction is v, and assume the pulse duration is t. The algorithm calculates the light-on event used to illuminate feature 306. The light-on event can be calculated when the entire feature 306 is within the illumination field 310. This occurs in the y-direction. If the holder position is offset by yHS relative to the substrate origin in the y-direction, then the holder position at the light-on time is . The light-on event can be calculated based on the holder position, time, or any other parameter that can be determined from the parameters of the deposition process. If the light-on event is time-based, then it will be the time at which it occurs.

[0034] Minimize the duration of light activation to avoid image distortion. The substrate and imaging system can move relative to each other during image capture. If the duration of the illumination scene is longer than the time required to capture the desired image, it can cause a decrease in image sharpness. The algorithm calculates the light deactivation event after the feature has crossed the illumination field following the light activation event. This occurs when the light is in the y-direction. Algorithm 300 can calculate the position of the light deactivation holder as or at what time. The pulse duration is selected as the time it takes for the feature to cross the illumination field.

[0035] The imaging system is positioned such that the x-position of the illumination field is identical to the designed x-position of the feature. The imaging system uses an illumination source that can transition from zero to peak intensity and from peak intensity to zero in a time much shorter than the pulse duration. The LED light source can transition as quickly as the potential across each LED light source can transition; therefore, the LED light source can be pulsed during the short duration described herein. The LED light source also emits uniform radiation, and in most cases, it can obtain a clear image without further homogenization.

[0036] Figure 4 is a flowchart outlining a method 400 for capturing images of positional features on a substrate. At 402, the substrate is positioned on a substrate support of a processing device. Typically, the processing device is used to perform a procedure, such as adding material to or removing material from the substrate, and the positioning features of the substrate guide the procedure. The positional features may be specific features added to the substrate for positioning the substrate, such as markings or structures, or the positional features may be features added to the substrate for another purpose and here for positioning the substrate.

[0037] At 404, the substrate is positioned for imaging by the imaging system. The substrate can be moved relative to the imaging system to the appropriate position by moving the substrate using a substrate holder. In some cases, the substrate support includes a frictionless surface, allowing the substrate holder to move the substrate with minimal resistance. In some cases, the imaging system can also be moved. For example, an air bearing coupled to a guide rail can be used to deploy the imaging system on the positioning system. The imaging system may include an LED light source oriented to direct illumination radiation to the imaging area. The imaging unit is positioned close to the LED light source to image the radiation reflected from the substrate.

[0038] A positioning substrate is used to capture an image at a location determined by a desired position of a positioning feature. The desired position of the positioning feature is a predetermined position on the substrate where the positioning feature is expected to be found. The imaging system and the substrate are positioned relative to each other such that the desired position is near the illumination field of the illumination source.

[0039] At 406, the scanning substrate is relative to the imaging system. The expected position of the positioning feature moves toward the edge of the illumination field of the illumination source. When the expected position is a predetermined distance from the edge of the illumination field, the imaging unit is activated to begin acquiring image data. At this time, the illumination source is not in operation. Typically, the processing device has an isolation substrate support and an imaging system housing, so any light source other than the illumination source is minimized.

[0040] At 408, the illumination source is activated when the image of the positioning feature can be captured by the imaging unit. The illumination source can be activated when a portion of the positioning feature is expected to enter the illumination zone, when a fraction of the positioning feature within the illumination field of the expected illumination source is at its maximum value, or when the entire positioning feature is initially expected to be within the illumination field of the illumination source. In one case, the illumination source is activated when the leading edge of the expected positioning feature reaches the edge of the illumination field. The expected position of the positioning feature can be at the end of the positioning feature or at the center of the positioning feature. If the expected position of the positioning feature is at its end, the illumination source can be activated when the expected position of the expected positioning feature reaches the edge of the illumination field. If the expected position of the positioning feature is at its center, the known dimensions of the positioning feature can be used to determine the expected position of the end of the positioning feature, and the illumination source can be activated when the expected position of the end of the expected positioning feature reaches the edge of the illumination zone.

[0041] In other situations, the illumination source can be activated when the expected positioning feature or a large portion thereof is entirely within the illumination field of the illumination source. In this situation, the illumination source is activated when the rear edge of the expected positioning feature reaches the edge of the illumination zone, determined by the known geometry of the positioning feature and the expected position. Waiting until the largest or all of the positioning feature is within the illumination field of the illumination source to activate the illumination source minimizes the exposure time used for image capture, and thus minimizes substrate movement during image capture. Minimizing substrate movement during image capture produces the sharpest image.

[0042] At 410, the substrate and the imaging system are scanned together such that a positioning feature or a portion thereof traverses the illumination field of the illumination source during the traverse time. The traverse time can be defined in several ways. In one case, the traverse time is the time between the first end of the positioning feature entering the illumination field of the illumination source and the last end of the positioning feature leaving the illumination field of the illumination source. In another case, the traverse time is the time between the last end of the positioning feature entering the illumination field (where no other end of the positioning feature subsequently enters the illumination field) and the first end of the positioning feature leaving the illumination field. In either case, all or only a portion of the positioning feature may traverse the illumination field. The traverse can occur in as little as 1 µsec. The traverse time can be determined using the known size of the illumination field and by the traverse speed.

[0043] At 412, the lighting source is deactivated. The effective time of the lighting source is defined as the time between when the lighting source is activated and when it is deactivated. The effective time of the lighting source may be the same as or different from the traverse time. The effective time of the lighting source may coincide with or overlap with the traverse time, or may overlap with or cover the traverse time. In one case, the effective time coincides with or overlaps with the traverse time. In another case, the effective time is contiguous with and overlaps with the traverse time. In yet another case, the effective time occurs simultaneously with the traverse time and may overlap with or cover the traverse time. In any case, both the effective time and the traverse time are related to the desired portion of the lighting positioning characteristics during the traverse time.

[0044] In cases where an image of the entire positioning feature is required, but the image of the entire positioning feature cannot be captured in a single exposure due to factors such as the size of the illumination field of the illumination source or the size of the imaging field of the imaging unit, the substrate and imaging system can be repositioned in a manner similar to method 400 for a second exposure to capture additional portions of the positioning feature.

[0045] At 414, the imaging unit is deactivated. The imaging time can be defined as the time between when the imaging unit is activated and when it is deactivated. The imaging time is longer than the effective time of the illumination source because obtaining a short light pulse is more straightforward than obtaining useful exposure with a short exposure time. In the specific examples described herein, the positioning feature may have a size of approximately 1 μm, and the substrate scanning speed may be up to 1 m / sec. Therefore, in some situations, images can be captured for a duration of 1 µsec using the methods and apparatus described herein. Such short-duration exposures are more easily achieved using a short effective time of 1 µsec and a longer imaging time of 1 msec or greater.

[0046] The repeatable method 400 is used to image a plurality of positioning features. In each case, the expected position of the positioning feature is known, and the substrate and imaging system are positioned to place the expected position near the illumination field of the illumination source. It should be noted that due to errors in substrate placement, imaging system placement, application of the positioning feature to the substrate, and thermal displacement and distortion, the image acquired using the expected position of the positioning feature may not capture the desired image. In such cases, the captured image can be analyzed to determine the magnitude and direction of the applicable position correction. Method 400 can then be repeated, thereby applying the position correction before or during the execution of method 400. Typically, the expected position of the positioning feature is modified by position correction before repeating method 400, but in addition to modifying the expected position of the positioning feature, or instead of modifying the expected position of the positioning feature, a bias can also be applied to the position of the substrate and / or the imaging system.

[0047] Figure 5 is a flowchart outlining a method 500 that can be used with the apparatus and other methods described herein. Method 500 is a method for determining the position and orientation of positioning features of a substrate from an image obtained by pulse illumination. At 502, an image of an area of ​​the substrate is obtained at the location where the positioning features are expected to be found. This image is obtained using an imaging system described herein.

[0048] At 504, a set of grid points is defined within the image. The grid points are defined by xy coordinates in a common coordinate system for points in the image. That is, the image is acquired by positioning the imaging system at points defined by these coordinates. The geometry of the imaging system determines the coordinates of the image boundaries in the coordinate system. Grid points are defined between the coordinates of the image boundaries. Any number of grid points can be used, with more grid points being helpful when the positioning features have more complex shapes.

[0049] The expected shape and size of a positioning feature are typically defined by coordinates within the same coordinate system. For example, the vertices of a polygonal positioning feature can be defined by an ordered set of coordinate pairs, where neighboring coordinate pairs define the positions of vertices connected by edges. For non-polygonal shapes with curved profiles, coordinates can define neighboring points on the edge profile of the shape. Further points in the shape definition of this shape are improved by minimizing the error of the assumed straight edges between adjacent points.

[0050] At 506, for each grid point defined at 504, a plurality of lines are defined passing through that grid point. These lines can be defined as a set of coordinate pairs representing each pixel of the image along the lines, or they can be defined as a set of endpoints. The number of lines is predetermined based on the complexity of the imaged shape, and the number of lines can be increased if the first execution of method 500 produces unsatisfactory definitions of the positioning features in the image. These lines are typically chosen to uniformly cover the plane, for example, radiating from the origin at equal angles.

[0051] At 508, for each line defined at 506, the brightness change between different pixels of the image along that line is determined. For each pixel P1 on the line defined by a coordinate pair (xp1, yp1) belonging to the set of coordinate pairs of the defining line, the brightness BP1 of that pixel is determined. The brightness BP2 of at least one adjacent pixel P2 on the line at coordinates (xp2, yp2) is also determined. The two brightnesses are subtracted by BP2 - BP1 to determine the brightness change at pixel P1. Typically, absolute values ​​are used. This type of brightness change is a "forward" brightness change. Alternatively, a "backward" brightness change can be used, in which P1 is compared with the previous pixel P0, or a "center" brightness change can be used, in which the average brightness changes between P0 and P1 and P2.

[0052] Brightness changes are typically used to indicate where boundaries may be located in an image. At 510, a predetermined number of pixels with the highest brightness change are recorded, and points along the lines with the highest brightness change values ​​are considered candidates for shape boundaries within the image. Operations 506 – defining the lines, 508 – analyzing brightness changes along these lines, and 510 – recording the maximum brightness change value are repeated for all grid points defined in the image. From this process, a set of points representing candidate points used to define the edges of captured shapes in the image is obtained.

[0053] At point 512, the recorded points are analyzed to determine which points lie on the boundaries of the image of the location feature. Any number of shape recognition algorithms can be used to determine which points can be used to define the positions of the boundary edges of shapes in the image. The choice of algorithm can be influenced by the known shape of the location feature. For example, if the known shape is circular or nearly circular, equidistant distances from the points can be used as a search criterion. For more complex shapes, distance-based signatures can be calculated in a matching algorithm. For example, test shapes bounded by the known shape and size of the location feature can be defined by coordinates, and the distances from the recorded points to the test shapes can be determined. Test shapes that minimize distance statistics can then be sought within the constraints of the known shape and size. The results of this search can be improved by excluding statistical outliers to resolve the "best" score for each test shape, and the test shape with the best total score can be identified as the most likely representation of the shape in the image.

[0054] From this optimal test shape, further shape improvements can be performed. For example, if the test shape has a boundary defined by coordinate pairs of pixels on the boundary, curvature measurements can be applied pixel by pixel to improve the test shape fitted to the recording points. At 514, based on the analysis at 512, the coordinate set is defined as the boundary representing the location features in the image.

[0055] After defining the boundaries of a positioning feature in the image using coordinates, the characteristics of the positioning feature in the image can be determined. At point 516, the centroid of the coordinates defining the boundary of the positioning feature can be calculated as the "center" of the feature. This position can be recorded in the system as the actual position of the positioning feature on the substrate. Alternatively, the maximum or minimum x-value and the maximum or minimum y-value can be used as the position of the positioning feature. When the position is defined at point 516, the positional error of the positioning feature can be determined at point 518. The positional error is the difference between the coordinates of the positioning feature defined according to image analysis and the expected coordinates of the positioning feature. This positional error can be used to adjust the processing plan of the substrate.

[0056] At 520, a rotation error can be defined for the positioning feature. A rotation transformation can be applied to the coordinate set that defines the boundary of the positioning feature in the image. For example, the rotation angle can be defined in radians, and the xy shift of each pixel in the coordinate set defining the boundary of the positioning feature in the image can be defined based on the radial coordinates of each pixel. After applying the rotation transformation, the difference between the rotated coordinate set of the image boundary and the expected coordinate set of the positioning feature boundary can be calculated. The degree of rotation that minimizes this difference can be used as the rotation error of the image. The rotation error can be calculated before or after adjusting any positional errors identified at 518.

[0057] At 522, an error shape error can be defined for the positioning feature. The error shape error records the distortion of the positioning feature from its expected shape. Failure to detect and compensate for error shape errors may lead to processing errors introduced based on the assumption that the positioning feature shape is correct. For example, if a corner of a square positioning feature is misplaced, making the positioning feature not a perfect square, the positioning feature can be found and located, but its position may be incorrectly recorded by the processing system based on the error shape. Typically, the error shape error is determined after compensating for any positional and rotational errors. The pixel-by-pixel error of the position-compensated and rotation-compensated images can be calculated and recorded as the error shape error. For the purpose of processing the substrate, the recorded position of the positioning feature can be adjusted based on the identified error shape error.

[0058] Method 500 can be used to locate and define a plurality of positioning features of a substrate. Errors detected in the plurality of positioning features can be analyzed to identify systematic errors in the placement and orientation of the substrate in a processing system. For example, similar rotational or positional errors among the plurality of positioning features can indicate the total rotational or positional error during substrate placement. Different rotational or positional errors can indicate substrate distortion or misalignment of positioning features on the substrate. Method 500 and its variations are executed using a digital processing system programmed with instructions suitable for displaying the various coordinates and calculations mentioned in method 500. The digital processing system receives data representing an image from an imaging unit and automatically identifies the boundaries of features in the image, and, as appropriate, identifies positional errors, rotational errors, and incorrect shape errors of positioning features in the image. The results of method 500 can be used, for example, with a deposition apparatus 100 as shown in FIG. 1 to control the precise deposition of material onto a substrate.

[0059] FIG6 is an isometric top view of a deposition apparatus according to another specific embodiment. The apparatus of FIG6 is similar to that of FIG1, except that the imaging system 150 is absent. In fact, the first imaging system 650 is movably coupled to the imaging rail 604, which is part of the deposition assembly support 616. The deposition assembly support 616 is similar to the deposition assembly support 116 of FIG1, including a beam or rail 117, which in this case is the deposition rail. The deposition assembly support 616 includes an extension 620 that supports the first imaging system 650 and the second imaging system 652. The extension 620 includes a first riser 622 extending from a first end 624 of the beam 117 and a second riser 626 extending from a second end 628 of the beam 117 opposite to the first end 624. The extension 620 further includes an imaging guide 604 that extends from the first riser 622 to the second riser 626 and is substantially parallel to the crossbeam 117.

[0060] Each of the first imaging system 650 and the second imaging system 652 is substantially identical to imaging system 150. The first imaging system 650 is coupled to the imaging rail 604 via a first imaging bracket 654. The second imaging system 652 is coupled to the imaging rail 604 via a second imaging bracket 656. A distributor housing 119 is located between the first imaging system 650 and the second imaging system 652. Each of the first imaging bracket 654 and the second imaging bracket 656 has a lateral extension that supports the first imaging system 650 and the second imaging system 652 at a certain gap from the imaging rail 604. This gap allows each of the first imaging system 650 and the second imaging system 652 to move along substantially the entire length of the imaging rail 604 without being disturbed by the deposition housing 119.

[0061] The device 600 has four independently movable imaging systems. The two imaging systems 650 and 652 described above are located on the first side of the deposition support assembly 616. The device 600 has a third imaging system 660 and a fourth imaging system 662, each of which is similar to imaging systems 650 and 652. Here, imaging rail 604 is a first imaging rail, and second imaging rail 664 is part of the deposition support assembly 616. In this configuration, both the first imaging rail 604 and the second imaging rail 664 are mounted on two risers 622 and 626, and extend parallel to each other between the two risers 622 and 626. Imaging systems 660 and 662 are each supported on the second imaging rail 664 by an imaging bracket. Specifically, the third imaging bracket 674 is coupled to the second imaging rail 664 to support the third imaging system 660, and the fourth imaging bracket 676 is coupled to the second imaging rail 664 to support the fourth imaging system 662. The space between imaging rails 604 and 664 allows the first bracket 654 and the second bracket 656 to move along the first imaging rail 604 without interference from the third bracket 674 and the fourth bracket 676. In this way, all four imaging systems can be positioned along the substantially entire length of the deposition support assembly 616. The use of multiple imaging systems allows for the capture of a large number of images in a shorter time, thus speeding up the imaging process.

[0062] Any number of imaging systems described herein can be used with this device. Figure 6 illustrates four imaging systems, but any number of such imaging systems can be used. For example, two imaging systems can be used on one of two imaging rails, or two imaging systems can be used, one on each imaging rail. Imaging systems can be added to one or two imaging rails simply by placing the bracket of the imaging system on the desired imaging rail. In some cases, the bracket is coupled to the imaging rail using an air bearing, thus enabling the air bearing of the added imaging system to allow the added imaging system to move along the selected imaging rail. Deploying multiple imaging systems using LED light sources allows the device to simultaneously image multiple locations using the brightness, uniformity, and fast pulse time of LED radiation, thus increasing the speed of imaging various portions of the substrate. Using multiple imaging devices can also improve the accuracy of imaging at a location by acquiring and comparing two or more images of a single location on the substrate.

[0063] Although the foregoing content is directed to specific examples of the present invention, other and additional specific examples of the present invention may be designed without departing from the basic scope of the present invention, and the scope of the present invention is determined by the following claims. [Simplified Explanation of the Diagram]

[0009] To enable a more detailed understanding of the above-described features of the invention, a more specific description of the invention briefly summarized above can be obtained by referring to specific examples, some of which are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings are merely illustrative examples and should therefore not be considered as limiting the scope of the invention; other equally effective examples are permissible.

[0010] [Figure 1] is an isometric top view of a deposition apparatus according to a specific example.

[0011] [Figure 2] is a block diagram of the system obtained based on the location of a specific instance.

[0012] [Figure 3] is an algorithm diagram of a droplet jetting algorithm based on a specific example.

[0013] [Figure 4] is a flowchart of a method based on a specific example.

[0014] [Figure]5 is a flowchart outlining a method that can be used with the devices and other methods described herein.

[0015] [Figure 6] is an isometric top view of a deposition apparatus according to another specific example.

[0016] For ease of understanding, reference numerals have been used where possible to indicate common elements in the figures. It has been considered that elements and features of one particular instance may be beneficially incorporated into other particular instances without further description.

Claims

1. A deposition apparatus comprising: a substrate support; and a deposition assembly including a fiber-coupled laser imaging system disposed across the substrate support, the laser imaging system including a laser source, an imaging unit and an optical component for directing laser radiation from the laser source to the substrate support and for directing reflected laser radiation to the imaging unit.

2. The deposition apparatus of claim 1, wherein the deposition assembly comprises: a guide rail attached to a support located on an opposite side of the substrate support, and a distributor assembly movably coupled to the guide rail.

3. The deposition apparatus of claim 2, wherein the dispenser assembly houses the laser imaging system.

4. The deposition apparatus of claim 1, wherein the laser source has an emission wavelength of at least about 600 nm.

5. The deposition apparatus of claim 4, wherein the imaging unit has an imaging unit having a sensitivity curve that matches the emission wavelength of the laser source.

6. The deposition apparatus of claim 5, wherein the laser source has a pulse duration of 1 μsec or less.

7. The deposition apparatus of claim 6, further comprising a controller configured to scan the substrate and enable the imaging unit for an imaging time, wherein the effective time is covered by the imaging time.

8. The deposition apparatus of claim 7, wherein the laser source is a laser diode.

9. The deposition apparatus of claim 1, wherein the laser imaging system is one of a plurality of laser imaging systems coupled to the deposition assembly.

10. A method of imaging a feature on a substrate, comprising: scanning the substrate relative to a laser imaging system comprising a laser source and an imaging unit; activating the imaging unit before an end of the feature reaches an illumination field of the laser source; activating the laser source when a portion of the feature reaches the illumination field; deactivating the laser source after an effective time; and deactivating the imaging unit after an imaging time, wherein the imaging time covers the effective time.

11. The method of request item 10, wherein the effective time is less than 5 μsec.

12. The method of claim 11, wherein the imaging unit is a camera having sensitivity matching the emission wavelength of the LED light source.

13. The method of claim 12, further comprising positioning the substrate and the imaging system relative to each other based on a predetermined position of one of the features.

14. The method of claim 13, further comprising automatically identifying one of the boundaries of the feature in the image.

15. The method of claim 14, further comprising automatically identifying one of the positional errors of the feature.

16. The method of claim 14 further includes automatically identifying one of the rotational errors of the feature.

17. The method of claim 10, wherein the laser imaging system is a first laser imaging system, and the method further comprises: capturing a first image of the feature using the first laser imaging system; and capturing a second image of the feature using a second laser imaging system.

18. The method of claim 17, wherein the first laser imaging system and the second laser imaging system are coupled to a support member that extends transversely over a substrate support member on which the substrate is disposed for imaging.

19. A deposition apparatus comprising: a substrate support; and a deposition assembly including a laser imaging system disposed across the substrate support, the laser imaging system including: a laser source optically coupled to an optical component to direct laser radiation from the laser source to the substrate support; and an imaging unit disposed to capture laser radiation reflected through the optical component.

20. The deposition apparatus of claim 19, further comprising a position controller for positioning the laser imaging system.

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