JP2006292426A - Coordinate-measuring method and dimension measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coordinate-measuring method capable of measuring the coordinates of alignment marks, even when the accuracy of the coordinate measurement of the alignment mark is low in rough alignment. <P>SOLUTION: This measuring method comprises a step for photographing the alignment mark in low-magnification mode, a step for roughly estimating the position of the alignment mark from an image obtained by that photographing, a step for setting an origin of coordinates on a substrate, on the basis of information on the roughly estimated position of the alignment mark, a step for photographing the alignment mark in a high-magnification mode, on the basis of the set origin of the coordinates, a step for detecting the position of the alignment mark from an image obtained from that photographing in the high-magnification mode, a step for resetting the origin of the coordinates on the basis of information on the detected position of the alignment mark, a step for re-photographing the alignment mark in the high-magnification mode, on the basis of the reset origin of the coordinates, and a step for detecting the position of the alignment mark from an image obtained by re-photographing in the high-magnification mode. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a coordinate measurement method and a dimension measurement method using this coordinate measurement method, and in particular, a coordinate measurement method suitable for coordinate measurement of alignment marks formed on the surface of a substrate such as a liquid crystal display panel, The present invention relates to a dimension measuring method suitable for measuring the dimension of a predetermined portion of a substrate based on the measured coordinates.

  A general liquid crystal display panel includes an array substrate having an array of thin film transistors formed on the surface thereof, and a color filter having an array of colored layers of red (R), blue (B), and green (G) formed on the surface thereof. The substrate is disposed to face the substrate with a predetermined interval, and the gap is filled with liquid crystal.

  The array of thin film transistors on the array substrate is generally formed by a photolithography method. At this time, the magnification of the array pattern of the formed thin film transistors may change due to thermal expansion and contraction of the array substrate due to temperature change. Further, if the mirror of the interferometer provided in the exposure apparatus is distorted, the array pattern of the exposed thin film transistors may be distorted into, for example, a parallelogram.

  When the array substrate in which the magnification of the arrangement pattern of the thin film transistors is changed or the shape of the arrangement pattern of the thin film transistors is distorted and the color filter substrate are bonded together, the arrangement pitch of the thin film transistors and the arrangement pitch of the colored layers are increased. It will shift. When this deviation is large, such a liquid crystal panel is a defective product. Therefore, before bonding to the color filter substrate, the dimension of the arrangement pattern of the thin film transistors formed on the surface of the array substrate is measured to prevent such defective products from occurring.

  For example, an ultra-precise coordinate measuring device is used to measure the dimensions of predetermined locations on the substrate, such as the dimensions and shape of the array pattern of thin film transistors formed on the surface of the array substrate. Then, first, a rough alignment is used to measure the approximate coordinates of the alignment mark formed on the surface of the substrate, and then the fine alignment based on the measurement result is used to accurately measure the alignment mark coordinates. Is used.

  Specifically, for example, an image obtained by capturing an alignment mark on the substrate in advance is registered as a model pattern. In rough alignment, a specific region of the substrate on which the alignment mark is formed is imaged by a low-magnification (wide-field) imaging unit, and the coordinates of the alignment mark are calculated by pattern matching between this image and the model pattern. Next, in fine alignment, a method is used in which an area where an alignment mark is formed is photographed by a high-magnification imaging unit based on the calculated coordinates, and the coordinates of the alignment mark are measured with high accuracy from the photographed image.

  According to such a two-stage method, the time required for fine alignment can be shortened, and as a result, highly accurate coordinate measurement and dimension measurement can be performed in a short time.

  However, in such a method, if the measurement accuracy of the coordinates of the alignment mark by rough alignment is low, when the alignment mark is photographed by the high-magnification imaging means in fine alignment, the alignment mark is taken from the field of view of the high-magnification imaging means. It becomes easy to slip. In particular, in a model pattern that has been captured in advance, a position that serves as a reference for coordinate measurement (for example, the center of an image frame) and a position that serves as a reference for coordinate measurement in a captured alignment mark (for example, the center of an alignment mark). This deviation occurs when the point is misaligned. If the deviation is large, it is difficult or impossible to recognize the alignment mark, and an error that the coordinate measurement or the dimension measurement cannot be performed occurs.

  When such an error occurs, it is necessary to restart coordinate measurement from the beginning for the substrate on which the error has occurred. In addition, when this error continues, it may be necessary to re-shoot the model pattern.

JP 2005-25111 A

  Such measurement re-measurement due to an error or re-shooting of a model pattern requires time, so that it is necessary to prevent an error from occurring in order to shorten the process time. Further, in capturing the model pattern, it is extremely difficult to capture an image in which the center of the alignment mark is accurately positioned at the center of the image frame, for example. Therefore, it is desirable that coordinate measurement can be continued without causing an error even when the alignment mark is not accurately positioned at a predetermined position of the image frame in the model pattern.

  In view of the above situation, the problem to be solved by the present invention is a coordinate measuring method that can measure the coordinates of the alignment mark in the subsequent fine alignment even when the accuracy of the coordinate measurement of the alignment mark in the rough alignment is low. Or a dimension measuring method using such a coordinate measuring method.

  In order to solve such a problem, a coordinate measuring apparatus including an imaging unit capable of imaging in at least two modes of a low magnification mode and a high magnification mode and a recognition unit of an image captured by the imaging unit is used as follows. To measure the coordinates of the alignment mark.

  First, an image obtained by photographing the alignment mark is registered in the coordinate measuring apparatus as a model pattern. Here, the image to be registered as the model pattern may have a slightly shifted position between the image frame and the reflected alignment mark.

  Next, a design area where the alignment mark is formed is photographed in a low magnification mode, and the position of the alignment mark is measured by applying a pattern matching method to the photographed image using the model pattern. A coordinate system is set on the substrate based on the detected position information of the alignment mark, and a design area on the substrate where the alignment mark is formed is photographed in the high magnification mode based on the set coordinate system. Here, if there is a shift in the position of the image frame and the alignment mark in the model pattern, the measurement result includes the shift. For this reason, the alignment mark may not be sufficiently reflected in the image taken in the high magnification mode in order to detect the position of the alignment mark.

  Therefore, the deviation of the coordinate system is corrected using this image. That is, the position of the alignment mark is detected from the image photographed in the high magnification mode, and the coordinate system is reset on the substrate based on the detected position information of the alignment mark. Then, based on the reset coordinate origin, the design area on the substrate where the alignment mark is formed is re-photographed in the high magnification mode, and the position of the alignment mark is finally determined from the image re-photographed in the high magnification mode. To measure.

  Here, as a method of detecting the position of the alignment mark from the image taken in the high magnification mode for resetting the coordinate system, the edge of the alignment mark reflected in the taken image is detected, and this detection is performed. A method of calculating the center position of the alignment mark based on the designed shape dimension of the alignment mark from the formed edge can be applied.

  In addition, as a method of finally detecting an alignment mark from an image retaken in the high magnification mode, the edge of the alignment mark reflected in the taken image is detected and the center of the opposite edge is calculated. Thus, a method for calculating the center position of the alignment mark can be applied.

  As a substrate dimension measuring method, a method for calculating the dimension between the alignment marks from the coordinates of the alignment marks detected by the respective methods can be applied.

  According to such a configuration, an image photographed based on the reset coordinate system is used for measuring the coordinates of the alignment mark with high accuracy. In such an image, since the shift of the position of the image frame in the model pattern and the alignment mark reflected in the model pattern is corrected, the alignment mark is not greatly shifted from the image frame. Therefore, when measuring the position of the alignment mark with high accuracy, it is possible to suppress the occurrence of an error that measurement cannot be performed, and the trouble of re-measurement, re-imaging of the model pattern, and re-registration is reduced. For this reason, the time of the coordinate measurement process can be shortened.

  In addition, as a method of measuring the center of the alignment mark when resetting the coordinate origin, if the method of estimating from the edge of the alignment mark reflected in the image frame is used, at least the edge of the alignment mark is included in the image frame. If is reflected, the center coordinates of the alignment mark can be measured. For this reason, generation | occurrence | production of the error that a measurement cannot be performed can be suppressed.

  Then, in the coordinate measurement of the alignment mark with high accuracy, if the method of detecting the edge of the alignment mark reflected in the captured image and calculating the center of the opposite edge is used, Even if there is an error in the size and shape, the coordinates can be measured accurately. And since the image image | photographed on the basis of the coordinate origin reset as mentioned above is used, generation | occurrence | production of the error that a measurement cannot be performed can be suppressed.

  Embodiments of the present invention will be described below in detail with reference to the drawings. In the following description, the coordinate measuring method according to the present invention may be referred to as “the present method”.

  The embodiment described below is a method of measuring the coordinates of alignment marks formed at a plurality of predetermined positions on the substrate surface. Here, a method of measuring the coordinates of a total of four alignment marks, each of which is formed in a substantially square shape and in the vicinity of the four corners, will be described as an example. By measuring the coordinates of the plurality of alignment marks with high accuracy, the distance between the alignment marks and the relative positional relationship can be measured. As a scene where such a method is applied, for example, in the array substrate of a liquid crystal display panel, the coordinates of a plurality of alignment marks formed together with the gate pattern of the thin film transistor on the surface of the array substrate are measured, and thereby the dimensions of the gate pattern are measured. And a step of measuring the shape.

  This method is performed using, for example, an ultra-precise coordinate measuring apparatus. An ultra-precision coordinate measuring apparatus for realizing the present invention includes a stage on which a substrate is placed and an imaging means (hereinafter referred to as “alignment”) that can move on the stage and photograph a predetermined area of the substrate placed on the stage. And a processing means for storing and recognizing images taken by the alignment camera and performing other necessary processes. In addition, this alignment camera has at least two modes of a low magnification (wide field of view) and a high magnification, and is configured to be able to shoot by appropriately switching the modes. Such a configuration is realized in a conventional general ultra-precision coordinate measuring apparatus, and this method can be realized using such a conventional general ultra-precision coordinate measuring apparatus. Detailed description of the configuration of the apparatus will be omitted.

  The embodiment of the method includes a rough alignment step and a fine alignment step, and the fine alignment step further includes a first step of fine alignment and a second step of fine alignment. In the rough alignment process, the approximate coordinates of the alignment marks formed on the substrate are measured using an image pattern matching method. In the fine alignment step, the coordinates of the alignment mark are measured with high accuracy using a predetermined method described later. And the dimension and positional relationship between alignment marks are measured from this measurement result.

  First, an image to be used as a model pattern at the time of performing the pattern matching method is photographed and registered in the ultra-precision coordinate measuring apparatus. This model pattern is an image obtained by photographing an alignment mark formed on the substrate surface. FIG. 1 is a diagram schematically showing model patterns used in this method. FIG. 1A shows an ideal model pattern, and FIG. 1B shows an actual model pattern. It is a figure. As shown in FIG. 1, in the present embodiment, a substantially cross-shaped alignment mark in which two line segments are orthogonal to each other is used.

  The center point 24 of the image frame 21 is used as a reference point for coordinate measurement in the image frame 21. On the other hand, the intersection 13 of the center lines 11 and 12 of the two line segments constituting the alignment mark 1 is used as a reference point for coordinate measurement in the alignment mark 1 (hereinafter, the intersection 13 of the center lines 11 and 12). (Referred to as “alignment mark center point 13”). In the model pattern used in the pattern matching method, it is preferable that the point serving as the reference for coordinate measurement in the alignment mark is accurately located at the point serving as the reference for coordinate measurement in the image frame. Accordingly, in this model pattern, it is preferable that the center point 24 of the image frame 21 and the center point 13 of the alignment mark 1 are exactly coincident with each other as in the ideal model pattern 2 shown in FIG. .

  However, in reality, it is extremely difficult to capture an image in which the center point 24 of the image frame 21 and the center point 13 of the alignment mark 1 exactly match. Further, in order to photograph an image in which the center point 13 of the alignment mark 1 is accurately positioned at the center point 24 of the image frame 21, it is necessary to carefully align the alignment camera. It takes time. For this reason, a slight deviation between the center point 24 of the image frame 21 and the center point 13 of the alignment mark 1 is allowed. Therefore, in practice, an image in which the center point 24 of the image frame 21 and the center point 13 of the alignment mark 1 are shifted, such as the actual model pattern 2 'shown in FIG.

  In the rough alignment process, the approximate coordinates of each alignment mark are measured using the registered model pattern. First, the outer shape of the substrate is measured by, for example, a method in which pressing pins are brought into contact with the four corners of the substrate placed on the stage of the ultra-precision coordinate measuring apparatus, and the center point of the substrate is calculated from the measured outer shape. The calculated center point is set as the coordinate origin of the substrate. Using the coordinate origin as a reference, the alignment camera is moved to a design position where each alignment mark is formed, and an area including the position is photographed in the low magnification mode.

  Then, the pattern matching method is performed on the photographed image using the registered model pattern. Specifically, first, a pattern approximate to a registered model pattern is searched and collated from within a predetermined area of a photographed image. The coordinate of the center point of the image frame of the model pattern when the most approximate pattern is obtained is taken as the measurement result of the coordinate of the center point of the alignment mark. Note that the pattern matching method used in this method can be the same as the conventional general pattern matching method used for image recognition and the like, and thus detailed description of the processing procedure, processing contents, and the like will be omitted.

  Next, a coordinate system used as a reference for coordinate measurement in the fine alignment process is set based on the measured coordinates of the center point of each alignment mark. FIG. 2 is a diagram schematically showing a method for setting the coordinate system. Referring to FIG. 2, out of a total of four alignment marks 1a, 1b, 1c, and 1d formed in the vicinity of the four corners of substrate 3, alignment marks adjacent to each other (in FIG. 2, 1a and 1b, The midpoints 43 and 44 of two places 1c and 1d) are calculated, and the midpoints of the two midpoints 43 and 44 thus calculated are further calculated. A coordinate system is set in which the midpoint is the coordinate origin O of the substrate, the axis passing through the two midpoints 43 and 44 calculated earlier is the x axis, and the axis orthogonal to the x axis is the y axis.

  3A and 3B are schematic diagrams showing an actual setting state of the coordinate system. FIG. 3A shows the entire substrate, and FIG. 3B shows a model pattern used for coordinate measurement of the alignment mark. FIG. 3C is a diagram showing the coordinate origin of the set coordinate system and its vicinity, and is an enlarged view of the vicinity of the portion A in FIG. In the model pattern 2 ′ shown in FIG. 3B, the center point 13 of the reflected alignment mark 1 is deviated from the center point 24 of the image frame 21. In the figure, the deviation amount of the x axis is indicated by a symbol a, and the deviation amount of the y axis is indicated by a symbol b.

  In the pattern matching method of this method, the coordinates are measured on the assumption that the center point 13 of the alignment mark 1 is located at the center point 24 of the image frame 21 of the model pattern 2 '. Therefore, when the pattern matching method is executed using the model pattern 2 'shown in FIG. 3B, a measurement result is obtained in which the coordinates of the alignment marks are displaced by this displacement amount. FIG. 3A schematically shows the deviation between the actual coordinates of the alignment marks 1a, 1b, 1c, and 1d and the measured coordinates of the alignment marks 1a ', 1b', 1c ', and 1d'. As shown in FIG. 3A, the coordinates of the alignment marks 1a ′, 1b ′, 1c ′, and 1d ′ according to the measurement result are model patterns from the coordinates of the actual alignment marks 1a, 1b, 1c, and 1d. The image frame and the alignment mark are displaced by the amount of deviation. As a result, as shown in FIG. 3 (c), the coordinate origin O ′ set from the measured coordinates of the alignment marks 1a ′, 1b ′, 1c ′, 1d ′ becomes the actual alignment marks 1a, 1b, If it is set based on the coordinates of the center points 1c and 1d, it is at a position deviated from the point O that would have been the coordinate origin. In FIG. 3C, the amount of deviation of the x-axis between the set coordinate origin O 'and point O is indicated by symbol c, and the amount of deviation of the y-axis is indicated by symbol d.

  Next, the fine alignment process is performed. This fine alignment process includes a first process and a second process. The first step is a step of correcting a shift of the coordinate origin set by the rough alignment step and setting a more accurate coordinate system. The second step is a step of measuring the coordinates of the alignment mark with high accuracy using the coordinate system reset in the first step as a reference.

  In the first step of fine alignment, first, the coordinate origin O ′ (see FIG. 3A or 3C) set by the rough alignment step is used as a reference at a design position where an alignment mark is formed. The alignment camera is moved to photograph the alignment mark formed on the substrate in the high magnification mode.

  FIG. 4 is a schematic diagram showing a positional relationship between an image frame of an image photographed in the high magnification mode and an alignment mark. 4A shows a state in which the center point 54 of the image frame 51 and the center point 13 of the alignment mark 1 coincide with each other, and FIG. 4B shows the center point 13 of the alignment mark 1. FIG. 4C is a diagram showing a state where the center point 13 of the alignment mark 1 is greatly deviated from the center point 54 of the image frame 51. is there.

  When photographing the alignment mark formed on the surface of the substrate in the high magnification mode, when the center point 13 of the alignment mark 1 is accurately positioned at the center point 54 of the image frame 51, as shown in FIG. Images can be obtained. However, in actuality, the actual coordinates of each alignment mark are different from the design coordinates due to changes in the magnification of the pattern due to temperature changes and deformation of the pattern due to the distortion of the mirror of the interferometer during the photolithography exposure. It may be off. Furthermore, when the model pattern used in the pattern matching method in the rough alignment process is misaligned between the center point of the image frame and the center point of the alignment mark reflected in the image frame, this misalignment is referred to as the misalignment. Is added. Therefore, actually, as shown in FIG. 4B or 4C, the center point 54 of the image frame 51 of the photographed image is shifted from the center point 13 of the alignment mark 1 reflected there. There may be.

  In the conventional coordinate measurement method, the coordinates of the center point 13 of the alignment mark 1 are measured with high accuracy using such an image. There are various high-accuracy coordinate measuring methods, and one of them will be briefly described with reference to FIG. First, each of the two line segments constituting the alignment mark 1 is reflected in the image frame 51 among the edges 61 to 68 of these line segments at positions on both sides before and after the intersection. The portions 61a to 68a are detected. In FIG. 4, the portions 61 a to 68 a that are reflected in the image frame 51 of each edge 61 to 68 are highlighted with bold lines. Then, the center lines 11 'and 12' of the two line segments are measured from the detected edges 61a to 68a. Specifically, the middle of each pair of parallel edges (in FIG. 4A, each pair of 61a and 62a, 63a and 64a, 65a and 66a, and 67a and 68a) is set as the center line of each line segment. The intersection of these center lines 11 ′ and 12 ′ is set as the center point 13 of the alignment mark 1. This measuring method is called “multi-point registration mark center width”.

  When such a method is used, the coordinates of the center point 13 of the alignment mark 1 can be measured with high accuracy. However, in such a method, when the center point 54 of the image frame 51 and the center point 13 of the alignment mark 1 reflected in the image frame 51 are shifted, the coordinates of the center point 13 of the alignment mark 1 may not be measured. Arise. Specifically, as shown in FIG. 4B, when the lengths of the portions 61a, 62a, 67a, 68a reflected in the image frame 51 of the edges 61, 62, 67, 68 are short, It may be difficult to measure the center lines 11 ′ and 12 ′ between the edges. Further, as shown in FIG. 4C, when there are edges (in this case, edges 61, 62, 63, 65, 67, 68) that are not reflected in the image frame 51, The center line cannot be measured with a simple method.

  Therefore, the misalignment between the center point 54 of the image frame 51 and the center point 13 of the alignment mark 1 reflected in the image frame 51 is corrected so that high-precision measurement can be performed using the “multi-point registration mark center width”. A new coordinate system is set for capturing an image in which the deviation is reduced.

  FIG. 5 is a diagram schematically showing a method for newly setting a coordinate system from the image shown in FIG. The photographed image 5 is analyzed based on the coordinate system set in the rough alignment process, and two orthogonal edges 64a and 66a are detected from the edges of the alignment mark 1 reflected in the image frame 51. . Next, from the detected positions of the edges 64a and 66a, a distance of 1/2 of the designed line width of the line segment constituting the alignment mark 1 (indicated by symbol e in the drawing) is placed on the center side of the line segment. Center lines 11 "and 12" are set at the offset positions. The intersection of the set center lines 11 ″, 12 ″ is set as the center point 13 ″ of the alignment mark 1. According to such a method, the center point 13 of the alignment mark 1 is displaced from the center point 54 of the image frame 51. Even in such a case, the coordinates of the center point of the alignment mark can be measured if at least two orthogonal edges of the two line segments constituting the alignment mark 1 are reflected. For this reason, it is possible to suppress the occurrence of an error that the coordinate measurement of the center point of the alignment mark 1 becomes impossible.

  Then, a new coordinate system is set from the coordinates of the center point 13 ″ of the alignment mark 1 measured in this way. The method for setting the coordinate system here is the same as the method used in the rough alignment step. The description is omitted because it can be applied (see FIG. 2).

  Next, the process proceeds to the second step of fine alignment. First, the alignment camera is moved to a design position where the center point of the alignment mark on the substrate surface is formed with reference to the coordinate system newly set in the first step of fine alignment. Then, the alignment mark on the substrate is photographed again in the high magnification mode. Here, since the coordinate origin position is corrected in the first step of fine alignment, the image taken in this way is shifted from the center point 54 of the image frame 51 of the center point of the reflected alignment mark. Is getting smaller. For this reason, as shown in FIG. 4C, an image in which only a part of the eight edges of the alignment mark 1 is reflected in the image frame 51 is rarely captured.

  Then, the coordinates of the center point of each alignment mark are measured with high accuracy from the photographed image. The “multi-point registration mark map center width” can be applied to the high-precision coordinate measurement method here.

  Thus, if the center point coordinates of the alignment mark are measured with reference to the coordinate system reset in the first step of fine alignment, the measurement becomes less likely to be impossible. For this reason, it is possible to reduce the trouble of re-measurement of coordinates and re-shooting and registration of an image as a model pattern. As a result, the time required for coordinate measurement can be shortened. This is particularly effective when a large number of substrates are processed in a flow operation.

  In this method, depending on conditions, it is also possible to immediately measure the coordinate of the alignment mark with high accuracy without correcting the coordinate system set in the rough alignment step.

  The re-setting of the coordinate system performed in the first step of fine alignment is when the edge required for highly accurate coordinate measurement of the alignment mark is not reflected in the image frame of the image shot in the high magnification mode. Is required. Referring to FIG. 4, when the coordinates of the center point 13 of the alignment mark 1 are measured based on the “multi-point registration mark center width”, as shown in FIG. If only the edges 64a and 66a are reflected, the coordinates cannot be measured. Further, as shown in FIG. 4B, even if eight edges 61a to 68a are reflected, if there is an edge that does not reflect the length necessary for calculating the center line, the coordinate measurement is performed. (In FIG. 4B, the edges 61a, 62a, 67a, 67a correspond to this).

  However, as a result of taking an alignment mark in the high magnification mode using the coordinate system set in the rough alignment process as a reference, all the images taken are aligned to the extent that high-precision measurement can be performed using the “multi-point mark mark center”. There may be a case where the mark 1 is reflected. In such a case, it is not necessary to newly set the coordinate system, and the coordinate measurement by “multi-point mark mark center” may be performed immediately.

  Hereinafter, as a modification, a configuration in which the resetting of the coordinate system is omitted depending on conditions will be described. In the following description, portions that are different from the above embodiment will be mainly described, and the same portions will be omitted. First, an image to be used as a model pattern in the execution of the pattern matching method is photographed in advance and registered in the ultraprecision coordinate measuring apparatus. Then, the coordinate system is set by measuring the coordinates of the alignment mark using the registered model pattern. The configuration of the model pattern and the rough alignment process are the same as the configuration shown in the above embodiment.

  In the fine alignment process, first, the alignment camera is moved to a design position where an alignment mark on the substrate surface is formed, using the coordinate origin set in the rough alignment process as a reference. Then, each alignment mark formed on the substrate surface is photographed in the high magnification mode, and the coordinates of the center point of the alignment mark are measured with high accuracy. This “multi-point registration mark center width” can be applied to this measuring method.

  However, as shown in FIG. 4C, the photographed image may not include an edge necessary for measuring the center point by the “multi-point registration mark mark center” in the image frame 51. Further, as shown in FIG. 4B, even when all necessary edges are reflected, the length necessary for measurement may not be reached. In such a case, as shown in the embodiment, a new coordinate system is set without performing highly accurate coordinate measurement. Thereafter, the coordinates of the center point of each alignment mark are measured with high accuracy by the same method as that of the above embodiment.

  According to such a configuration, the same operational effects as in the above-described embodiment can be obtained, and when high-precision coordinate measurement can be performed using the coordinate system set in the rough alignment step as a reference, immediately, Since highly accurate coordinate measurement can be performed, measurement time can be shortened.

  The embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention is not limited to the embodiments, and various modifications can be made without departing from the spirit of the present invention. It goes without saying that it is possible.

  For example, in the above-described embodiment, the configuration applied to a substrate that is square and has one alignment mark formed at each of the four corners thereof is shown, but the position and number of alignment marks are not limited. Also, the shape of the alignment mark is not limited to a substantially cross shape, and any shape can be used as long as the center position can be estimated from part of the edge of the alignment mark. For example, the present invention can also be applied to circular or polygonal alignment marks.

In the coordinate measuring method which concerns on this invention, it is the figure which showed typically the image used as a model pattern of a pattern matching method, (a) shows an ideal model pattern, (b) shows an actual model pattern. . In the coordinate measuring method which concerns on this invention, it is the figure which showed typically the setting method of a coordinate system. It is the figure which showed the setting state of the actual coordinate system in the said method, (a) is the figure which showed the whole board | substrate, (b) is the figure which showed the model pattern of the pattern matching method used for the setting, (c) ) Is an enlarged view of the coordinate origin of (a) and its vicinity. It is the figure which showed the relationship between the alignment mark image | photographed in high magnification mode, and an image frame, (a) is the figure which showed the state with which the center of an image frame and the center of an alignment mark correspond, (b). The figure which showed the state from which the center of the alignment mark shifted | deviated a little from the center of an image frame, (c) is the figure which showed the state which the center of the alignment mark shifted | deviated largely from the center of an image frame. In the said method, it is the figure which showed typically the method of measuring the center point of an alignment mark in the case of correction of a coordinate system.

Explanation of symbols

1 alignment mark 2 model pattern 3 substrate 11 and 12 alignment mark center line 13 alignment mark center point 21 model pattern image frame 24 model pattern center point 43 and 44 alignment mark center point 51 Photographed in high magnification mode Image frame 54 Image center point taken in high magnification mode

Claims (4)

  A coordinate measuring method using a coordinate measuring apparatus including an imaging unit capable of imaging in at least two modes, a low magnification mode and a high magnification mode, and a recognition unit for an image captured by the imaging unit. Registering it as a model pattern in a coordinate measuring device, photographing a design area where an alignment mark is formed in a low-magnification mode, and applying a pattern matching method to the photographed image using the model pattern Detecting the alignment mark by applying, setting a coordinate system on the substrate based on the position information of the detected alignment mark, and on the substrate on which the alignment mark is formed based on the set coordinate system Steps to shoot a design area in high magnification mode and shot in high magnification mode Detecting the position of the alignment mark from the image; resetting the coordinate system on the substrate based on the detected alignment mark position information; and forming the alignment mark based on the reset coordinate system. A coordinate measurement method comprising the steps of: re-imaging a design area on a substrate in a high-magnification mode; and detecting the position of an alignment mark from an image re-photographed in the high-magnification mode.   The step of detecting the position of the alignment mark from the image photographed in the high magnification mode includes the step of detecting the edge of the alignment mark reflected in the photographed image, and the design of the alignment mark from the detected edge. The coordinate measuring method according to claim 1, further comprising: calculating a center position of the alignment mark based on the shape dimension.   The step of detecting the alignment mark from the image recaptured in the high magnification mode includes the step of detecting the edge of the alignment mark reflected in the captured image and the step of calculating the center of the opposite edge. The coordinate measuring method according to claim 1, wherein The dimension measuring method characterized by measuring the dimension between each alignment mark from the coordinate of the alignment mark measured by the coordinate measuring method in any one of Claims 1-3.

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