Apparatus for positioning substrate for deposition apparatus and method thereof

Abstract

To provide a deposition apparatus comprising a substrate support portion and a deposition assembly comprising a laser imaging system disposed over the substrate support portion.SOLUTION: There is provided a method of imaging a feature portion on a substrate, the method comprising: scanning the substrate relative to a laser imaging system 150 comprising a laser light source 152 and an imaging portion 154; activating the imaging portion before an edge of the feature portion reaches an illumination field of the laser light source; activating the laser light source when a portion of the feature portion reaches the illumination field; deactivating the laser light source after an activation time; and deactivating the imaging portion after an imaging time, where the imaging time comprises the activation time.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims the benefit of U.S. Provisional Patent Application No. 62 / 872,501, filed Jul. 10, 2019, which is hereby incorporated by reference in its entirety.

[0002] Embodiments of the present invention generally relate to deposition apparatuses. Specifically, deposition apparatuses equipped with a movable service platform will be described.

Background Art

[0003] Inkjet - based deposition is generally used not only in office and home printers but also in industrial - scale printers used in display manufacturing, deposition in large - volume printed matter, material attachment to manufactured articles such as printed circuit boards, and construction of biological articles such as tissues. In commercial and industrial inkjet deposition apparatuses, and some consumer printers, a dispenser is used to attach materials to a substrate. The dispenser discharges a controlled amount of deposition material onto the substrate while controlling time and speed. The deposited material reaching the target position of the substrate forms a mark of a desired dimension and shape.

[0004] In industries such as display manufacturing, very high - precision deposition is performed by depositing extremely small amounts of material at extremely precise positions. The diameter of the deposited area may be 10 μm in some cases or 15 μm in others. To place materials on a substrate with such precision, accurate positioning of the substrate and / or accurate determination of the substrate position are required. Usually, a vision system using a camera is used to photograph the substrate and accurately determine its position, but image acquisition and image processing take time. There is a need for improvement in methods for accurately determining the substrate position for inkjet printing.

Summary of the Invention

[0005] According to the embodiments described herein, a deposition apparatus is provided that includes a substrate support portion and a deposition assembly including a laser imaging system disposed across the substrate support portion.

[0006] According to other embodiments described herein, a method of imaging features on a substrate includes scanning the substrate with a laser imaging system including a laser light source and an imaging unit, operating the imaging unit before an end of a feature reaches an illumination field of view of the laser light source, operating the laser light source when a portion of the feature reaches the illumination field of view, stopping the laser light source after an activation time, and stopping the imaging unit after an imaging time, wherein the imaging time includes the activation time.

[0007] According to other embodiments described herein, a deposition apparatus includes a substrate support portion and a deposition assembly including a laser imaging system disposed across the substrate support portion, wherein the laser imaging system includes a laser light source fiber coupled to an optical assembly and directing laser radiation toward the substrate support portion, and an imaging unit disposed to image laser radiation reflected from the optical assembly.

Brief Description of the Drawings

[0008] To enable a more detailed understanding of the above features of the present disclosure, the present disclosure outlined above will be described more specifically with reference to embodiments shown in the accompanying drawings, which show only exemplary embodiments and do not limit the scope thereof, and other embodiments having similar effects are also possible.

[0009]

Figure 1

[0010]

Figure 2

[0011]

Figure 3

[0012]

Figure 4

[0013]

Figure 5

[0014]

Figure 6

[0015] For ease of understanding, elements common between the drawings are denoted by the same reference numerals as much as possible.

[0016] The elements and features of one embodiment can be incorporated into other embodiments in a useful form without additional description.

MODE FOR CARRYING OUT THE INVENTION

[0017] In this specification, a deposition apparatus including a service platform will be described. The service platform is disposed above the working surface of the deposition apparatus, adjacent to the end of the working surface during storage, and at least a part thereof is stored lower than the reference height of the working surface, and thus the substrate can be inserted and removed. FIG. 1 is an isometric top view of a deposition apparatus 100 according to an embodiment. This deposition apparatus has a substrate support portion 102, a deposition assembly 104, and a holder assembly 106 for operating the substrate during deposition. The deposition apparatus 100 includes a base 108. The base 108 is usually a heavy object so as to minimize the vibration transmitted to the operating portion of the deposition apparatus 100. In one example, the base 108 is made of granite. The deposition assembly 104 includes a deposition assembly support portion 116 including stands 120 provided on both sides of the base 108 and a rail or beam 117 extending between the stands 120 across the substrate support portion 102.

[0018] The substrate support part 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 placement areas for the substrate that is put into and taken out of the deposition device 100, and the third section 102C is a working area for positioning the substrate to be processed with respect to the deposition assembly support part 116. The substrate support part 102 has a working surface 110 and means for making the working surface 110 substantially frictionless. The working surface 110 is a gas cushion table on which a gas cushion (for example, air, low-oxygen air, dry air, nitrogen, or other suitable gas) for floating the substrate is formed. The working surface 110 is characterized by a plurality of holes (not shown), and by gas jetting from these holes, an upward force for maintaining the substrate at a desired height above the working surface 110 is obtained. Also, some of the holes can be controlled to remove gas from the gas cushion for floating the substrate, and the height of the substrate can be locally and accurately controlled. In one embodiment, the third section 102C has a gas supply hole and a gas removal hole. By the gas supply hole and the gas removal hole, the gas in the gas cushion can be independently controlled, and thus it is possible to control the floating height of the substrate above the substrate working surface 110.

[0019] The deposition assembly 104 includes a dispenser assembly 114 connected to the beam 117. The dispenser assembly 114 includes a dispenser housing 119 connected to the deposition carriage 122. The deposition carriage 122 moves along the beam 117 to position the dispenser assembly 114 with respect to the substrate disposed on the third section 102C of the substrate support part 102. The dispenser housing 119 houses one or more dispensers (not shown) that discharge a certain amount of deposition material onto the substrate on the substrate support part 102 disposed below the deposition assembly 104.

[0020] The substrate is disposed below the deposition assembly 104 by the holder assembly 106. The holder assembly 106 makes reliable contact with the substrate during substrate loading and moves the substrate along the substrate support portion 102 to position the substrate relative to the deposition assembly 104 such that the printing material is accurately discharged onto the substrate. In this case, the holder assembly 106 extends generally in a first direction along the substrate support portion 102 and translates the substrate in the first direction during deposition. The first direction is indicated by arrow 124 in FIG. 1. The dispenser assembly 114 moves in a second direction generally perpendicular to the first direction. The second direction is defined by a beam 117 that extends substantially in the second direction and is indicated by arrow 126 in FIG. 1. The second direction 126 may be referred to as the "x direction" and the beam 117 as the "x beam".

[0021] The control unit 132 is operably connected to the holder assembly 106 and the deposition assembly 104 and controls the movement of the substrate disposed on the substrate support portion and the deposition onto the substrate. The control unit 132 may directly control the actuators of the holder assembly 106 and the deposition assembly 104, or may be operably connected to a holder assembly control unit connected to the holder assembly 106 and a deposition assembly control unit connected to the deposition assembly 104. The control unit 132 controls the movement and positioning of the substrate when there is a substrate on the substrate support portion 102. Further, the control unit 132 controls the movement of the dispenser assembly 114 along the beam 117 and the discharge of the deposition material from the dispenser assembly 114 onto the substrate.

[0022] The laser imaging system 150 is connected to the dispenser assembly 114. The laser imaging system 150 includes a laser light source 152 and an imaging unit 154. The laser light source 152 directs laser radiation onto a substrate on the substrate support 102 disposed below the dispenser assembly 114. The imaging unit 154 detects the laser radiation reflected from the substrate. The imaging unit 154 can include a digital camera or other high-precision imaging components. The imaging unit 154 also includes an optical system that focuses the laser radiation onto the imaging components. The laser light source 152 and the imaging unit 154 are arranged such that an illumination field is formed on the substrate within the imaging field of view of the imaging unit 154 by the laser light source 152.

[0023] The laser light source 152 can emit laser radiation selected such that the impact on other aspects of the deposition apparatus 100 and the processes performed by the deposition apparatus 100 is minimized. For example, a curable material is often deposited on a substrate using the deposition apparatus 100. Such materials can typically be cured using electromagnetic radiation of short wavelengths such as ultraviolet light. These materials are also sensitive to short-wavelength visible light and may also have a slight sensitivity to long-wavelength visible light. In industries such as display manufacturing, uniform processing is important to achieve high precision, so a laser light source with a long wavelength can be selected to minimize the impact on the deposited material. From this perspective, a laser light source with an emission wavelength of 650 nm or more is useful. In one example, the emission wavelength of the laser light source is 650 nm. In another example, the emission wavelength of the laser light source is 800 nm. The laser light source can be a laser diode or an assembly of laser diodes such as a laser diode bar. Also, the combination of the laser light source and the imaging components can be selected such that the sensitivity of the imaging components to the radiation emitted by the laser light source is maximized. For example, the sensitivity of the Dalsa Nano M2020 camera is almost maximum at a wavelength of 650 nm. In silicon-based near-infrared imaging units, the maximum sensitivity is generally around 800 nm.

[0024] In this case, the laser light source 152 is a fiber coupled to send laser emission to a light emitting surface that can be arranged near the substrate. By managing the diffusion of the laser emission in this way, an illumination field of a desired size can be formed. In many display applications, the substrate has positioning features such as recognition marks, and the position of the substrate can be accurately calibrated using these. The size of the mark may be small, for example, 1 mm to 5 mm. This mark may be cross-shaped. By fiber coupling, the emission surface can be arranged so that a spot covering the entire or most of the field of view necessary to confirm the position of the mark is formed by radiative diffusion.

[0025] The laser imaging system 150 is configured to acquire an image while the substrate and the dispenser assembly 114 move relative to each other. The relative movement may be at a speed of 1 m / s. The imaging control unit 158 is operably connected to the laser light source 152 and the imaging unit 154 and drives the acquisition of an image during the relative movement. In this example, the laser light source has a short pulse characteristic of at least 5 microseconds. That is, the pulse width defined as the duration from the pulse start time to the pulse end time is such that the average intensity of the radiation field increases, reaches half of the maximum value at the pulse start time, further increases and then decreases, and reaches half of the maximum value at the pulse end time in about 5 microseconds. A laser light source with a short pulse characteristic of at least 1 microsecond may also be used. The imaging control unit 158 includes a digital circuit that instructs the imaging unit 154 to start and stop imaging, instructs the laser light source 152 to switch on and off, or communicates an instruction to alternately emit pulses with a defined pulse width, and is realized by a printed circuit board. The imaging control unit 158 is operably connected to the control unit 132 and optionally other control units such as a holder assembly control unit and a dispenser assembly control unit. The imaging control unit 158 transmits and receives signals representing information used to control the imaging of the substrate. The imaging control unit 158 is configured to transmit a signal representing the image acquired by the imaging unit 154 to the control unit 132 for analysis. Further, the imaging control unit 158 is configured to control the imaging unit 154 and the laser light source 152 to acquire an image when it is predicted that a feature portion of the substrate, such as a positioning feature portion, is within the field of view of the imaging unit 154 based on information such as the predicted position of the feature portion received from the control unit 132 and the moving speed of the substrate.

[0026] FIG. 2 is an elevation view of a position acquisition system 200 according to an embodiment. The position acquisition system 200 includes a laser imaging system 150, and a substrate 202 to be processed is disposed on a substrate support portion 102. The laser imaging system 150 is operably connected to an imaging control unit 158, and this imaging control unit 158 is further operably connected to the system control unit 132 as described above. The laser imaging system 150 may also be operably connected to a positioning control unit 204 capable of controlling and adjusting the position of the laser imaging system 150. The positioning control unit 204 may adjust the position of the laser imaging system 150 with respect to the dispenser of the dispenser housing 119 in FIG. 1.

[0027] In this case, the laser imaging system 150 includes a laser light source 206 and an imaging unit 208. An optical assembly 210 optically couples the laser light source 206 and the imaging unit 208 to the substrate 202 to be imaged. The optical assembly may include lenses and mirrors that direct the focused light reflected from the substrate 202 to the imaging unit 208. An optical fiber 212 sends the laser radiation emitted by the laser light source 206 to a light emitting point 214. This light emitting point 214 may be located at the end of the optical assembly 210 distal from the substrate support 102, may 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 may be recessed within the optical assembly 210. The optical fiber 212 is supported by a support 216 that maintains the position of the light emitting point 214. The laser radiation is emitted from the optical fiber 212 at the light emitting point 214, passes through the gap between the light emitting point 214 and the substrate 202, and forms an illumination field of view 218. The dimensions of the illumination field of view 218 can be controlled by controlling the position of the light emitting point 214 relative to the substrate 202. During processing, the substrate 202 is typically scanned relative to the laser imaging system 150 so as to illuminate the imaging portion of the substrate 202, as schematically indicated by the arrow 220. The laser light source 206 operates when the imaging target portion of the substrate 202 is partially or fully within the illumination field of view 218 during relative scanning, and stops when the imaging target portion has passed through the illumination field of view 218 taking sufficient time to acquire a desired image of the entire imaging target area. This may be when the front end portion of the imaging target area exits the illumination field of view 218 or when the rear end portion of the imaging target area exits the illumination field of view 218.

[0028] Figure 3 is an algorithm diagram of an imaging control algorithm 300 according to an embodiment. The imaging control algorithm 300 is used in a deposition apparatus such as the deposition apparatus 100. The imaging control algorithm 300 generates a trigger for starting imaging of features on the substrate 202 by the imaging unit and a trigger for starting illumination by the illumination unit. The illumination unit may be a laser, but any device that can generate short-pulse radiation within the illumination field of view is acceptable. The pulse width is about 1 microsecond or shorter, and small features on the substrate can be imaged at a relative speed of up to 1 m / s.

[0029] The imaging control algorithm 300 uses the position marker together with the position signal from the substrate holder to determine the timing at which the imaging unit starts imaging and the timing at which the laser light source starts illumination. Generally, this algorithm uses a coordinate system defined for use by the control unit when the imaging control algorithm 300 is executed. An origin 302 is defined on the substrate, and this origin 302 is arranged at a known position (xS, yS) with respect to the fixed position 304 (xH, yH) of the holder, and this fixed position of the holder is also known. The designed position (xF, yF) of the feature 306 on the substrate is known with respect to the origin 302 of the substrate. In an embodiment where the substrate is moved in the y direction during processing, let the positions of the holder, the origin of the substrate, and the y-direction position of the feature be yh, ys, and yf, respectively. These positions are offset by the same distance 308 in the y direction from their respective fixed positions. When the laser imaging system is moved during processing, the position of the illumination field of view 310 at any point in time is yi. The designed dimensions of this feature are ΔxF and ΔyF. The illumination field of view 310 formed by the laser imaging system has a known position (xI, yI) with respect to the fixed position of the holder. The dimensions of the illumination field of view are ΔxI and ΔyI. Therefore, the illumination field of view extends in the y direction from yI - (1 / 2)ΔyI to yI + (1 / 2)ΔyI, and when the laser imaging system is moved, it extends from yi - (1 / 2)ΔyI to yi + (1 / 2)ΔyI. At any point during processing, the y-direction position yh of the holder can be known from the position of the actuator.

[0030] Information regarding various position markers is supplied to a control unit such as control unit 132. In this algorithm, based on the predicted position of the feature portion, the timing for operating the imaging unit and the laser light source to image the feature portion is determined. The size of the illumination field of view is set such that the deviation between the predicted position and the actual position of the feature portion is sufficiently within a range smaller than the range in which the entire feature portion exists within the illumination field of view during exposure.

[0031] Let the relative movement speed in the y direction between the substrate and the laser imaging system be v, and the pulse width be t. By this algorithm, an illumination on event for illuminating the feature portion 306 is calculated. The illumination on event may be calculated when the entire feature portion 306 exists within the illumination field of view 310. This calculation is performed in the y direction when yf-(1 / 2)ΔyF = yi-(1 / 2)ΔyI. When the position of the holder is displaced by yHS in the y direction with respect to the origin of the substrate, the position of the holder at the time of illumination on is yi-(1 / 2)ΔyI - yf+(1 / 2)ΔyF + yS + yHS. The illumination on event can be calculated from other arbitrary parameters determined by the holder position, time, or deposition job parameters. When the illumination on event is expressed as time, it is the time when vt = yi-(1 / 2)ΔyI - yf+(1 / 2)ΔyF.

[0032] To prevent image distortion, the illumination time of light is minimized. The substrate and the laser imaging system may be relatively moved during imaging. If illumination is performed more than necessary to obtain a desired image, the sharpness of the image may be impaired. In this algorithm, after the illumination on event, an illumination off event is calculated when the feature portion passes through the illumination field of view. This calculation is performed in the y direction when yf+(1 / 2)ΔyF = yi+(1 / 2)ΔyI. The imaging control algorithm 300 can calculate the position of the holder at the time of illumination off as yi+(1 / 2)ΔyI - yf-(1 / 2)ΔyF + yS + yHS, or as the time when vt = yi+(1 / 2)ΔyI - yf-(1 / 2)ΔyF. The pulse width is selected to be the time when the feature portion passes through the illumination field of view, that is, t=(1 / v)(ΔyI - ΔyF).

[0033] Position the laser imaging system such that the x-position of the illumination field of view is the same as the x-position of the designed feature on the substrate.

[0034] FIG. 4 is a flowchart showing an overview of an imaging method 400 for position features on a substrate. At 402, place the substrate on the substrate support of the processing apparatus. The processing apparatus is typically used to perform processes such as the attachment or removal of materials to / from the substrate. This process is guided using the positioning features of the substrate. The positioning features may be special features such as marks or structures specifically added to the substrate for substrate positioning, or features added to the substrate for other purposes may be used for substrate positioning.

[0035] At 404, position the substrate for imaging by the laser imaging system. By moving the substrate using a substrate holder, the substrate can be moved to a fixed position relative to the laser imaging system. The substrate support may include a frictionless surface, and the substrate holder can move the substrate with substantially no resistance. Also, the laser imaging system may be moved in some cases. For example, the laser imaging system may be placed on a positioning system using an air bearing connected to a rail. The laser imaging system includes a laser light source that directs laser radiation into the imaging area. The imaging unit is arranged close to the laser light source to image the laser radiation reflected from the substrate.

[0036] The substrate is placed at a position determined by the expected position of the positioning feature for imaging. The expected position of the positioning feature is a predetermined position on the substrate where the positioning feature is expected to be present. The laser imaging system and the substrate are positioned relative to each other such that the expected position is near the illumination field of view of the laser light source.

[0037] At 406, the substrate is scanned relative to the laser imaging system. The predicted position of the positioning feature moves towards the edge of the irradiation area of the laser light source. When the predicted position reaches a predetermined distance from the edge of the illumination field of view, the imaging unit activates to start acquiring image data. At this point, the laser light source is not operating. Since the processing device typically includes a housing that isolates the substrate support and the laser imaging system, light sources other than the laser light source are minimized.

[0038] At 408, when the imaging unit can acquire an image of the positioning feature, the laser light source is activated. The laser light source may be activated when a part of the positioning feature is expected to enter the illumination zone, when the ratio of the positioning feature present within the illumination field of view of the laser light source is expected to be maximized, or when the entire positioning feature is first expected to fit within the illumination field of view of the laser light source. In one example, the laser light source is activated when the leading edge of the positioning feature is expected to reach the edge of the illumination field of view. The predicted position of the positioning feature may be at the end of the positioning feature or at the center of the positioning feature. When the predicted position of the positioning feature is at the end, the laser light source is activated when the predicted position of the positioning feature is expected to reach the edge of the illumination field of view. When the predicted position of the positioning feature is at the center, the predicted position of the end of the positioning feature can be determined using the known dimensions of the positioning feature, and the laser light source is activated when the predicted position of the end of the positioning feature is expected to reach the edge of the illumination zone.

[0039] In other examples, the laser light source is activated when it is expected that the positioning feature or most of it is completely within the irradiation field of the laser light source. In this case, the laser light source is activated when it is predicted based on the known shape and predicted position of the positioning feature that the trailing edge of the positioning feature has reached the edge of the illumination zone. By waiting until the largest part, i.e., the whole, of the positioning feature fits within the irradiation area of the laser light source before activating the laser light source, the exposure time for imaging can be minimized, and thus the movement of the substrate during imaging can be minimized. By minimizing the movement of the substrate during imaging, the sharpest image can be obtained.

[0040] In 410, the substrate and the laser imaging system are scanned relative to each other such that the positioning feature or a part thereof passes through the illumination field of the laser light source during the transit time. The transit time can be defined in various ways. In one example, the transit time is the time from when the leading edge of the positioning feature enters the illumination field of the laser light source until the trailing edge of the positioning feature exits the illumination field of the laser light source. In another example, the transit time is the time from when the trailing edge of the positioning feature enters the illumination field and there is no other end portion of the positioning feature that will enter the illumination field thereafter until the leading edge of the positioning feature exits the illumination field. In either case, only the whole or a part of the positioning feature may pass through the illumination field. The transit time is on the order of 1 microsecond. The transit time can be determined using the known dimensions of the illumination field and the transit speed.

[0041] At 412, stop the laser light source. The operating time of the laser light source is defined as the time from when the laser light source starts operating until it stops. The operating time of the laser light source may be the same as or different from the passing time. The operating time of the laser light source may start at the same time as the passing time and be the same as the passing time, may partially overlap with the passing time, or may include the passing time. In one example, the operating time starts at the same time as the passing time and overlaps with each other. In another example, the operating time ends at the same time as the passing time and overlaps with each other. In yet another example, the operating time is parallel to the passing time and may partially overlap with the passing time or may include the passing time. In any case, the operating time and the passing time are related to the illumination of the desired portion of the positioning feature during the passing time.

[0042] An image of the entire positioning feature is required. However, for example, if the entire image cannot be obtained in one exposure due to the dimensions of the illumination field of the laser light source or the imaging field of the imaging unit, the substrate and the laser imaging system can be repositioned to perform a second exposure, and an additional portion of the positioning feature can be imaged in the same manner as in method 400.

[0043] At 414, stop the imaging unit. The imaging time can be defined as the time from when the imaging system starts operating until it stops. Since short laser pulses are simpler than obtaining effective exposure with short-time exposure, the imaging time is longer than the operating time of the laser light source. In the embodiments described in this specification, the dimensions of the positioning feature may be about 1 μm and the scanning speed of the substrate may be about 1 m / second. Therefore, using the methods and apparatuses described in this specification, imaging is performed with a duration of 1 microsecond. Such short-time exposure can be more easily realized by using a short laser operating time of 1 microsecond and a long imaging time of 1 millisecond or more.

[0044] Method 400 may be repeated to image a plurality of positioning features. In any case, the predicted position of the positioning feature is known, and the substrate and the laser imaging system are positioned such that the predicted position is near the irradiation field of the laser light source. Note that if there are misplacements of the substrate, misplacements of the laser imaging system, misattachments of the positioning feature to the substrate, displacements or distortions due to heat, etc., the image obtained using the predicted position of the positioning feature may not be the desired image. It should be noted that in such a case, the acquired image can be analyzed to determine the degree and direction of applicable position correction. Thereafter, Method 400 can be repeated while applying position correction before or during the implementation of Method 400. Usually, before repeating Method 400, the predicted position of the positioning feature is corrected by position correction. However, in addition to or instead of correcting the predicted position of the positioning feature, a bias can also be applied to the position of the substrate and / or the laser imaging system.

[0045] FIG. 5 is a flowchart showing an overview of Method 500 and other methods that can be used in the apparatus described herein. Method 500 is a method for determining the position and orientation of the positioning feature of the substrate from a laser-irradiated image. At 502, an image of the region of the substrate is acquired at a position where the positioning feature is expected to be included. This image is acquired using the laser imaging system described herein.

[0046] At 504, a set of grid points is defined within the image. The grid points are defined by the x-y coordinates of a common coordinate system using points within the image. That is, the imaging system is positioned at the points defined by the coordinates to acquire the image. The coordinates of the boundary of the image in the coordinate system are determined by the shape of the imaging system. The grid points are defined between the coordinates of the boundary lines of the image. Any number of grid points may be used, but when the positioning feature has a more complex shape, it is more effective to have more grid points.

[0047] The expected shape and dimensions of the positioning feature are typically defined by the coordinates of the same coordinate system. For example, each vertex of a polygonal positioning feature can be defined by an ordered set of coordinate pairs, and adjacent coordinate pairs define the positions of the vertices connected at the edges. In the case of a non-polygonal shape with a curved contour, each coordinate can define adjacent points on the contour of the shape's edge. To define such a shape, more points can be provided to minimize the error when assuming a straight-line edge between adjacent points and improve the shape definition.

[0048] In 506, for each grid point defined in 504, a plurality of lines passing through that grid point are defined. These lines can be defined as a set of coordinate pairs representing each pixel of the image along them, or they can be defined as a set of endpoints. The number of these lines is determined in advance based on the complexity of the shape to be imaged, and if the fineness of the positioning feature in the image obtained in the first implementation of method 500 is insufficient, the number can be increased. These lines are generally selected to uniformly cover the plane and are, for example, lines extending radially equiangularly from the origin.

[0049] In 508, for each line defined in 506, the luminance change between the pixels of the image along that line is determined. For each pixel P1 (coordinate pair (xP1, yP1)) on the line belonging to the set of coordinate pairs defining the line, the luminance BP1 of that pixel is determined. Also, the luminance BP2 of at least one adjacent pixel P2 (coordinates (xP2, yP2)) on that line is determined. The difference between these two luminances, BP2 - BP1, is calculated to determine the change in the luminance of pixel P1. Usually, the absolute value is used. This type of luminance change is the "forward" luminance change. It is also possible to use the "reverse" luminance change obtained by comparing pixel P1 with the preceding pixel P0 or the "central" luminance change, which is the average luminance change from P0 to P1 and from P1 to P2.

[0050] Luminance changes are generally used to indicate the boundary positions in an image. At 510, a predetermined number of pixels with the highest luminance changes, i.e., points with the highest degree of luminance change along the line, are recorded as candidates for the shape boundary within the image. The process 506 of defining each line, the process 508 of analyzing the luminance change along the line, and the process 510 of recording the maximum luminance change are repeated for all the grid points defined for the image. From this processing, a set of points representing candidate points that define the edge of the shape within the image is obtained.

[0051] At 512, the recorded points are analyzed to find the points on the boundary of the image of the positioning feature. Using any number of shape recognition algorithms, points that can be used to define the position of the boundary edge of the shape within the image are found. The selection of the algorithm depends on the known shape of the positioning feature. For example, if it is known that the shape is circular or approximately circular, the search condition can be that the distances from a certain point are equal. In the case of a more complex shape, a matching algorithm can be used to calculate the discrimination characteristics based on the distance. For example, a test shape defined by the known shape and dimensions of the positioning feature can be defined in coordinates, and the distances of the recorded points from the test shape can be obtained. Then, under the constraints of the known shape and dimensions, the test shape with the minimum distance statistic can be obtained. This search result can be improved by excluding statistical outliers, and the "best" score can be obtained for each test shape. The test shape with the overall best score can be identified as the shape that best represents the shape within the image.

[0052] Further improvement of the shape can be performed from the best test shape obtained in this way. For example, if the test shape has a boundary defined by a pair of coordinates of pixels on the boundary, a curvature metric can be applied to each pixel to improve it so that the test shape fits each recorded point. At 514, based on the analysis in 512, a set of coordinates representing the boundary of the positioning feature within the image is defined.

[0053] After defining the boundaries of the positioning feature in the image with coordinates, the characteristics of the positioning feature in the image can be determined. In 516, the centroid of the coordinates defining the boundary of the positioning feature is 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 also be used as the position of the positioning feature. When the position is defined in 516, the position error of the positioning feature can be determined in 518. The position error is the difference between the coordinates of the positioning feature defined from image analysis and the expected coordinates of the positioning feature. This position error can be used to adjust the processing plan of the substrate.

[0054] In 520, the rotation error of the positioning feature can be defined. A rotation transformation can be applied to the coordinate set defining the boundary of the positioning feature in the image. For example, the rotation angle can be defined in radians, and the x - y displacement 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 boundary of the positioning feature is calculated. The degree of rotation at which this difference is minimized can be taken as the rotation error of the image. The rotation error can be calculated either before or after adjusting the position error if the position error is identified in 518.

[0055] In 522, the shape distortion error of the positioning feature can be defined. The shape distortion error refers to the distortion from the expected shape of the positioning feature. If this shape distortion error is detected and not corrected, a processing error may occur because it is based on the premise that the positioning feature is properly formed. For example, if a corner of a square positioning feature is misaligned, and as a result the positioning feature is not a perfect square, the positioning feature can be recognized and located, but since its position is based on the incorrect shape, it may be incorrectly recorded in the processing system. The shape distortion error is usually determined after correcting any position error and rotation error. The error for each pixel of the image with corrected position and rotation can be calculated and recorded as the shape distortion error. The recorded position of the positioning feature for substrate processing can be adjusted based on the determined shape distortion error.

[0056] Using method 500, the positions of a plurality of positioning features of a substrate can be identified and defined. By analyzing the errors detected in the plurality of positioning features, systematic errors in the arrangement and orientation of the substrate in the processing system can be identified. For example, if there are similar rotation or position errors between a plurality of positioning features, it can indicate the overall rotation or position error in the arrangement of the substrate. If there are differences in rotation or position errors, it can indicate that there are distortions or displacements in the positioning features on the substrate. Method 500 and its variations are implemented using a digital processing system programmed with appropriate instructions to perform the various coordinates and calculations referred to in method 500. The digital processing system receives data representing an image from an imaging unit and automatically identifies the boundaries of the positioning features in the image, and optionally the position error, rotation error, and shape distortion error of the positioning features in the image. Utilizing the results of method 500, for example, the deposition of materials onto a substrate can be precisely controlled using the deposition apparatus 100 of FIG. 1.

[0057] FIG. 6 is an isometric top view of a deposition apparatus according to another embodiment. The apparatus of FIG. 6 is similar to the apparatus of FIG. 1, except that it does not include the laser imaging system 150. Instead, a first laser imaging system 650 is movably connected to an imaging rail 604 that is part of the deposition assembly support 616. The deposition assembly support 616 includes a beam or rail 117, similar to the deposition assembly support 116 of FIG. 1, which in this case is a 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 upright portion 622 extending from a first end 624 of the deposition rail 117 and a second upright portion 626 extending from a second end 628 of the deposition rail 117 opposite the first end 624. The extension 620 further includes an imaging rail 604 extending from the first upright portion 622 to the second upright portion 626, and this imaging rail 604 is substantially parallel to the deposition rail 117.

[0058] Each of the first imaging system 650 and the second imaging system 652 is substantially the same as the laser imaging system 150. The first imaging system 650 is connected to the imaging rail 604 by a first imaging carriage 654. The second imaging system 652 is connected to the imaging rail 604 by a second imaging carriage 656. The dispenser housing 119 is located between the first imaging system 650 and the second imaging system 652. Each of the first imaging carriage 654 and the second imaging carriage 656 has a lateral extension that supports the first imaging system 650 and the second imaging system 652 spaced from the imaging rail 604. This spacing 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 interfered with by the dispenser housing 119.

[0059] The apparatus 600 has four independently movable imaging systems. The two imaging systems 650 and 652 described above are disposed on the first side surface of the deposition assembly support 616. The apparatus 600 has a third imaging system 660 and a fourth imaging system 662, each of which is a laser imaging system similar to the imaging systems 650 and 652. In this example, the imaging rail 604 is the first imaging rail, and the second imaging rail 664 is part of the deposition assembly support 616. The first imaging rail 604 and the second imaging rail 664 are both disposed on the two rising portions 622 and 626 in this case, and extend parallel to each other between the two rising portions 622 and 626. The imaging systems 660 and 662 are each supported by the second imaging rail 664 by an imaging carriage. Specifically, the third imaging carriage 674 is connected to the second imaging rail 664 to support the third imaging system 660, and the fourth imaging carriage 676 is connected to the second imaging rail 664 to support the fourth imaging system 662. The space between the imaging rail 604 and the imaging rail 664 enables the first imaging carriage 654 and the second imaging carriage 656 to move along the first imaging rail 604 without being interfered by the third imaging carriage 674 and the fourth imaging carriage 676. In this way, all four imaging systems can be arranged over substantially the entire length of the deposition assembly support 616. By using multiple imaging systems, a large number of images can be acquired in a shorter time, and the processing that depends on imaging can be accelerated.

[0060] In such an apparatus, any number of the laser imaging systems described in this specification can be used. Although four imaging systems are illustrated in FIG. 6, any number of such imaging systems can be used. For example, two imaging systems may be used on one of the two imaging rails, or one imaging system may be used on each of the two imaging rails. The imaging system can be added to one or both of the imaging rails simply by placing the carriage of the imaging system on the desired imaging rail. The carriage may be connected to the imaging rail using an air bearing. Therefore, the air bearing of the additional imaging system can be activated and the additional imaging system can be moved along the selected imaging rail. By arranging a plurality of laser imaging systems, a plurality of positions can be simultaneously imaged using the imaging accuracy by laser radiation, and the imaging speed of each part of the substrate can be increased. Further, when two or more images are acquired and compared for a single location on the substrate using a plurality of imaging devices, the imaging accuracy can be improved.

[0061] Although the embodiments of the present invention have been described above, other embodiments and further embodiments of the present disclosure can be devised without departing from its basic scope, which is defined by the following claims.

Claims

1. A method for imaging features on a substrate, said method comprising: scanning the substrate relative to a laser imaging system including a laser light source, an imaging unit, an optical assembly connecting the laser light source and the imaging unit, and an optical fiber disposed within the optical assembly and connected to the laser light source; activating the imaging unit before the leading edge of the feature reaches an illumination field of the laser light source; activating the laser light source when a portion of the feature reaches the illumination field; acquiring an image of the feature using the imaging unit while the feature is within the illuminated field of view; deactivating the laser light source after an activation time; and stopping the imaging unit after an imaging time, wherein the imaging time comprises the operating time.

2. The method of claim 1, wherein the actuation time is less than 5 microseconds.

3. The method described in claim 2, wherein the imaging unit is a camera whose sensitivity is tuned to the emission wavelength of the laser light source.

4. The method of claim 3, further comprising relatively positioning the substrate and the laser imaging system based on the predicted position of the feature.

5. The method of claim 4, further comprising automatically identifying boundaries of the feature within the image.

6. The method of claim 5, further comprising automatically identifying position errors of the features.

7. The method of claim 5, further comprising automatically identifying rotation error of the feature.

8. The laser imaging system, wherein the laser imaging system is a first laser imaging system, further comprising: 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.

9. The method described in claim 8, wherein the first laser imaging system and the second laser imaging system are connected to a support that crosses over a substrate support on which the substrate is placed.

10. A method for imaging features on a substrate, the method comprising: scanning the substrate relative to a laser imaging system including a laser light source, an imaging unit, an optical assembly connecting the laser light source and the imaging unit, and an optical fiber disposed within the optical assembly and connected to the laser light source; activating the imaging unit before the leading edge of the feature reaches an illumination field of the laser light source; causing the laser light source to emit pulsed light; acquiring an image of the feature using the imaging unit while the feature is within the illuminated field of view; and stopping the imaging unit after an imaging time has elapsed.

11. The method of claim 10, wherein the pulse width is less than 1 microsecond.

12. The method described in claim 10, wherein the pulse width is selected as the time it takes for the feature to pass through the illumination field.

13. The method of claim 10, wherein the pulse width is selected to minimize distortion in the acquired image.

14. The method of claim 10, wherein scanning the substrate comprises moving the substrate over a frictionless surface of the substrate support.

15. The method of claim 14, further comprising moving the laser imaging system.

16. The method of claim 10, wherein pulsing the laser light source includes calculating light-on events and light-off events.

17. The method of claim 16, wherein the illumination-on event is calculated as the time when the feature is within the illumination field of view.

18. The method described in claim 17, wherein the light-off event is calculated at the time when the feature passes through the illuminated field of view after the light-on event.

19. A method for imaging features on a substrate, the method comprising: scanning the substrate relative to a laser imaging system including a laser light source, an imaging unit, an optical assembly connecting the laser light source and the imaging unit, and an optical fiber disposed within the optical assembly and connected to the laser light source; activating an imaging unit before the leading edge of the feature reaches an illumination field of a laser light source; causing the laser light source to emit pulses with a pulse width of 5 microseconds or less; using the optical assembly to direct the laser light reflected from the substrate to the imaging unit; acquiring an image of the feature using the imaging unit while the feature is within the illuminated field of view; and stopping the imaging unit after an imaging time.

20. The method of claim 19, wherein scanning the substrate comprises using a substrate holder to move the substrate over a frictionless surface of a substrate support.

Images