JP2022069967A - Distortion aberration correction processing device, distortion aberration correction method, and program - Google Patents

Abstract

To provide a distortion aberration correction processing device capable of performing distortion aberration correction with high accuracy even when an optical axis of an imaging device is slanted with respect to the surface of the object to be measured.SOLUTION: A storage unit stores distortion aberration correction information showing the relationship between a coordinate correction factor that corrects the coordinates on the image plane and a distance from a reference point for each of a plurality of sections divided by a plurality of boundaries extending radially from the reference point of the image plane of an imaging device. A processing unit selects at least one section from the plurality of sections on the basis of the coordinates in the image plane of a point to be corrected, determines the coordinate correction factor on the basis of the distortion aberration correction information for the selected section and the distance from the reference point to the point to be corrected, and corrects the coordinates of the point to be corrected on the basis of the determined coordinate correction factor.SELECTED DRAWING: Figure 2

Description

The present invention relates to a distortion aberration correction processing device, a distortion aberration correction method, and a program.

An inkjet device that draws ink by landing ink on an object from an inkjet head, a laser processing device that performs drilling by injecting a laser beam onto an object, and an annealing device by injecting a laser beam onto a semiconductor substrate that is an object. In a laser annealing device or the like, the alignment mark provided on the object is detected to position the object. At this time, the position of the alignment mark is detected by performing image processing on the image on which the alignment mark is copied.

In order to detect the position of the alignment mark with high accuracy, it is preferable to correct the distortion of the lens (for example, Patent Document 1 below). In the distortion correction method disclosed in Patent Document 1, a five-dimensional polynomial correction formula is set as a function for correcting the distance (image height) from the origin of the image plane to the image after distortion to the distance before distortion. Using this multinomial equation, the distance after distortion is corrected to the distance before distortion.

Japanese Unexamined Patent Publication No. 2001-133223

When the optical axis of the image pickup device is slanted with respect to the surface of the object to be measured, the amount of distortion to be corrected changes depending on the position in the circumferential direction about the origin of the image plane. However, in the correction method disclosed in Patent Document 1, since the distortion is corrected only by the distance from the origin of the image plane, the distortion is corrected with high accuracy when the optical axis of the image pickup apparatus is tilted. Can't do.

An object of the present invention is a distortion aberration correction processing device capable of performing distortion aberration correction with high accuracy even when the optical axis of the imaging device is slanted with respect to the surface of the object to be measured, a distortion aberration correction method, and the like. And to provide a program.

According to one aspect of the invention
The relationship between the coordinate correction factor for correcting the coordinates on the image plane and the distance from the reference point for each of the plurality of sections divided by the plurality of boundaries extending radially from the reference point on the image plane of the image pickup apparatus. A storage unit that stores the distortion correction information shown, and
At least one section is selected from the plurality of sections based on the coordinates of the correction target portion in the image plane, the distortion aberration correction information for the selected section, and the distance from the reference point to the correction target location. Provided is a distortion aberration correction processing apparatus including a processing unit that determines a coordinate correction factor based on the above and corrects the coordinates of the correction target portion based on the determined coordinate correction factor.

According to another aspect of the invention
The relationship between the coordinate correction factor that corrects the coordinates in the image and the distance from the reference point for each of the plurality of sections divided by the plurality of boundaries extending radially from the reference point in the image plane of the image pickup apparatus. Using an image pickup device whose distortion aberration correction information is known, an image of the object to be measured is imaged.
The correction target location for correcting the coordinates in the image plane is determined, and the correction target location is determined.
At least one section is selected from the plurality of sections based on the position of the correction target portion in the image plane.
The coordinate correction factor is determined based on the distortion correction information for the selected section and the distance from the reference point to the correction target location.
Provided is a distortion aberration correction method for correcting the coordinates of the correction target portion based on the determined coordinate correction factor.

According to yet another aspect of the invention.
The relationship between the coordinate correction factor that corrects the coordinates in the image and the distance from the reference point for each of the plurality of sections divided by the plurality of boundaries extending radially from the reference point in the image plane of the image pickup apparatus. The procedure for acquiring an image of a measurement object captured by an image pickup device whose distortion aberration correction information is known, and
A procedure for determining a correction target portion to be corrected from an image captured by the image pickup device, and
A procedure for selecting at least one section from the plurality of sections based on the coordinates of the correction target portion in the image plane, and a procedure for selecting at least one section from the plurality of sections.
A procedure for determining the coordinate correction factor based on the distortion correction information for the selected section and the distance from the reference point to the correction target location.
A program for causing a computer to execute a procedure for correcting the coordinates of the correction target portion based on the determined coordinate correction factor is provided.

By dividing the image plane into multiple sections and correcting the distortion using the distortion correction information set for each section, the optical axis of the image pickup device becomes slanted with respect to the surface of the object to be measured. It is possible to correct distortion with high accuracy even in the presence state.

FIG. 1 is a block diagram of a distortion aberration correction processing device according to an embodiment. FIG. 2 is a diagram showing the contents of distortion aberration correction information. FIG. 3 is a graph for explaining a method of correcting the coordinates in the image plane of the correction target portion. FIG. 4 is a flowchart showing a procedure for correcting the coordinates in the image plane of the correction target portion. FIG. 5A is a diagram showing the distribution of images of a plurality of marks arranged in a matrix using a telesen lens, and FIG. 5B is a diagram calculated from the coordinates of the images of the marks using the method according to the present embodiment. It is a figure which shows the coordinates after correction of a mark. 6A and 6B are in the image plane when the optical axis of the image pickup device is perpendicular to the surface of the object to be measured, when it is assumed that there is no distortion and when it is assumed that there is distortion. FIG. 6C is a diagram showing an image of the mark, and FIG. 6C is a graph plotting the relationship between the coordinate correction factor D _x in the x direction with respect to the diagonal direction of the image plane and the distance r from the center point of the image plane. 7A and 7B show in-plane images of the case where the optical axis of the image pickup device can be tilted with respect to the surface of the object to be measured, the case where there is no distortion, and the case where there is distortion. It is a figure which shows the image of the mark of, and FIG. 7C shows the coordinate correction factor Dx in the _x direction about the diagonal direction of the image plane, and the image plane, without distinguishing the four diagonal directions of the image plane. It is a graph plotting the relationship with the distance r from the center point, and FIG. 7D distinguishes each of the sections Q1 to Q4, and shows the coordinate correction factor D _x in the x direction with respect to the diagonal direction of the image plane and the image plane. It is a graph which plotted the relationship with the distance r from the center point of. FIG. 8A is a schematic front view of the inkjet drawing apparatus according to another embodiment, and FIG. 8B is a diagram showing the positional relationship of the movable table, the ink ejection unit, and the image pickup apparatus in a plan view. FIG. 9 is a flowchart showing a procedure for drawing with an inkjet drawing device.

A distortion aberration correction processing device according to an embodiment will be described with reference to FIGS. 1 to 9.
FIG. 1 is a block diagram of a distortion aberration correction processing device 10 according to an embodiment. The distortion aberration correction processing device 10 according to the present embodiment includes an input / output interface unit 11, a processing unit 12, and a storage unit 13. For example, a computer is used for the processing unit 12. A program 14 executed by a computer is stored in the storage unit 13. Distortion correction information 15 is further stored in the storage unit 13. The contents of the distortion aberration correction information 15 will be described later with reference to FIG. As the storage unit 13, for example, an auxiliary storage device such as a hard disk drive (HDD) or a solid state drive (SSD) is used.

The processing unit 12 acquires image data from the image pickup device 40 via the input / output interface unit 11. The processing unit 12 detects the coordinates of the image of the alignment mark in the image by performing image analysis. The coordinates of this image deviate from the actual coordinates indicating the position of the actual alignment mark due to the influence of the distortion of the lens. The processing unit 12 corrects the coordinates of the image by using the distortion correction information 15 stored in the storage unit 13 to reduce the error of the alignment mark from the actual coordinates. After that, the corrected coordinates are passed to the control device 50 via the input / output interface unit 11. The control device 50 performs various processes based on the corrected coordinates of the alignment mark. The processing unit 12 and the control device 50 may be realized by a common computer. In this case, the processing unit 12 passes the corrected coordinates of the alignment mark to the control device 50 without going through the input / output interface unit 11.

FIG. 2 is a diagram showing the contents of the distortion aberration correction information 15. An xy orthogonal coordinate system with the reference point O as the origin is defined on the image plane 41 of the image pickup apparatus 40 (FIG. 1). An object point in the image field of the image pickup apparatus 40 is transferred to the image plane 41. The image plane 41 is, for example, a square or a rectangle, and the reference point O is the center of the square or the rectangle. The x-axis and y-axis are defined to be parallel to any side of the image plane 41.

The image plane 41 is divided into a plurality of sections Q1 to Q4 by a plurality of boundary lines BL extending radially from the reference point O. In the case of this embodiment, a line segment connecting the reference point O and the midpoint of each side of the image plane 41 is adopted as the boundary line BL. The four boundary lines BL correspond to the positive part and the negative part of the x-axis, and the positive part and the negative part of the y-axis, and the sections Q1 to Q4 correspond to the first quadrant to the first quadrant of the xy coordinate system, respectively. Corresponds to 4 quadrants.

Due to the influence of the distortion of the lens and the like, the position of the image point P1 corresponding to _a certain observation point deviates from the position of the image point _P0 when it is assumed that the lens has no aberration. The distortion correction information 15 is information for correcting the coordinates of the image _point P1 to obtain the coordinates of the image point P0 at the time of no aberration, and is the coordinate correction factor D in the _x direction and the coordinate correction in the _y direction. Includes rate D _y .

Next, a method of obtaining the distortion aberration correction information 15 for the section Q1 will be described. An observation object having a plurality of marks whose positions are known is imaged by an image pickup apparatus 40 (FIG. 1) to acquire an image. The plurality of marks are, for example, grid points in a grid pattern. The observation object is moved until the image of the mark serving as the reference point of the observation object coincides with the reference point O of the image plane 41. For example, by analyzing the image of the mark, detecting the position of the image of the mark, and moving the observation object based on the detection result, the image of the mark serving as the reference point becomes the reference point O of the image plane 41. Can be matched. This procedure may be repeated multiple times to improve the accuracy of the match between the two.

By analyzing the obtained image, a plurality of image points located on the diagonal line of the section Q1 having the reference point O as one end are extracted from the image points of the plurality of marks. _One of the extracted plurality of image points is referred to as P1. The image point at the time of no aberration corresponding to the image point P ₁ is expressed as P ₀ . _The coordinates of the image point P1 are obtained by performing image analysis. The coordinates of the image point P ₀ at the time of no aberration corresponding to the image point P ₁ are expressed as (x ₀ , y ₀ ), and the coordinates of the image point P ₁ are expressed as (x ₁ , y ₁ ). The coordinate correction factor D in the _x direction and the coordinate correction factor D _y in the y direction are defined by the following equations.

The coordinate correction factor D _x in the x direction is x from the image point P ₀ when there is no aberration to the actual image point P ₁ with respect to the length x ₀ in the x direction from the reference point O to the image point P ₀ when there is no aberration. It is a ratio of the amount of displacement in the direction x ₁ -x ₀ . The coordinate correction factor Dy in the y direction is the y direction from the image point P ₀ when there is no aberration to the actual image point P ₁ with respect to the length y ₀ in the y direction from the reference point O to the image point P ₀ when there is no displacement. It is a ratio of the displacement amount y ₁ − y ₀ of. Generally, the distortion of a lens is small at the center of the image plane and large at the periphery. Therefore, the coordinate correction factors D _x and D _y depend on the distance r from the reference point O.

On the graph where the horizontal axis is the distance r from the reference _point O to the actual image point P1 and the vertical axis is the coordinate correction factor Dx in the _x direction, the measurement results for _a plurality of diagonal image points P1 are shown. Plot. Determine an approximate curve that approximates the distribution of the plotted points. As a result, as shown in FIG. 2, the coordinate correction factor D _x in the x direction is defined as a function of the distance r for the partition Q1. Similarly, the coordinate correction factor D _y in the y direction is also defined as a function of the distance r. As a result, the distortion aberration correction information 15 can be obtained for the section Q1. In the graph of the distortion aberration correction information 15 for the section Q1 shown in FIG. 2, an example of the coordinate correction factor D _x in the x direction and the coordinate correction factor D _y in the y direction is shown by a thick solid line and a thin solid line, respectively.

Distortion correction information 15 can be obtained for the other sections Q2 to Q4 in the same manner. The obtained distortion aberration correction information 15 is stored in the storage unit 13 (FIG. 1). When the distortion does not depend on the radial direction centered on the reference point O, the coordinate correction factors D _x and D _y are substantially the same between the sections Q1 to Q4. However, in reality, the coordinate correction factors D _x and D _y vary between the sections Q1 to Q4 due to various factors. As a factor of the variation, for example, the inclination of the optical axis of the image pickup apparatus 40 with respect to the surface of the observation object can be mentioned.

Next, a method of correcting the coordinates of a certain portion (hereinafter referred to as a correction target portion) in the image plane 41 to the coordinates at the time of no aberration will be described with reference to FIGS. 3 and 4.
FIG. 3 is a graph for explaining a method of correcting the coordinates in the image plane 41 of the correction target portion Pt. FIG. 4 is a flowchart showing a procedure for correcting the coordinates in the image plane 41 of the correction target portion Pt.

First, the correction target portion Pt in the image plane 41 is determined. The correction target portion Pt corresponds to, for example, the center point of the image of the alignment mark. Two sections are selected from the four sections Q1 to Q4 based on the position of the correction target portion Pt (step S1). For example, among the boundary lines BL partitioning the four sections Q1 to Q4, two sections on both sides of the boundary line BL having the smallest angle from the reference point O toward the correction target portion Pt are selected. In FIG. 3, the positive portion of the y-axis corresponds to the boundary line BL satisfying this condition. Two compartments Q1 and Q2 on either side of the positive part of the y-axis are selected.

Next, based on the distortion correction information 15 (FIGS. 1 and 2) for the two selected compartments Q1 and Q2, the coordinates of the compartments Q1 and Q2 corresponding to the distance r from the reference point O to the correction target portion Pt. By weighted averaging the correction factors D _x and D _y , the coordinate correction factors D _ct (r) and D y _t (r) at the position of the correction target portion Pt are obtained (step S2). For example, the angle between the reference point O toward the geometric center of the two selected sections Q1 and Q2 (corresponding to the diagonal direction of the sections Q1 and Q2) and the direction from the reference point O toward the correction target point Pt. Weighted averaging is performed based on.

ここで、Ｄ_ｘ１（ｒ）、Ｄ_ｙ１（ｒ）は、それぞれ区画Ｑ１について求められたｘ方向及びｙ方向の座標補正率であり、Ｄ_ｘ２（ｒ）、Ｄ_ｙ２（ｒ）は、それぞれ区画Ｑ２について求められたｘ方向及びｙ方向の座標補正率である。 Corrected when the angles formed by the direction from the reference point O toward the geometric center of the two selected sections Q1 and Q2 and the direction from the reference point O toward the correction target point Pt are expressed as θ ₁ and θ ₂ , respectively. The coordinate correction factors _Dxt (r) and _Dyt (r) at the target location Pt are expressed by the following equations.

Here, D _x1 (r) and D _y1 (r) are the coordinate correction factors in the x-direction and the y-direction obtained for the compartment Q1, respectively, and D _x2 (r) and D _y2 (r) are the compartments, respectively. It is a coordinate correction factor in the x-direction and the y-direction obtained for Q2.

Next, the coordinates in the image plane of the correction target portion Pt are corrected based on the weighted averaged coordinate correction factors _Dxt and _Dyt at the correction target portion Pt (step S3). For example, when the coordinates of the correction target location Pt are expressed as (x ₁ , y ₁ ) and the corrected coordinates are expressed as (x ₀ , y ₀ ), the corrected coordinates are calculated using the following formula. ..

Next, the excellent effects of this embodiment will be described with reference to FIGS. 5A and 5B.
FIG. 5A is a diagram showing the distribution of images in which a plurality of marks arranged in a matrix are imaged using a telecentric lens. In FIG. 5A, the amount of deviation from the mark image to the actual image when there is no aberration is magnified 100 times. In FIG. 5A, it can be seen that barrel-shaped distortion occurs.

FIG. 5B is a diagram showing the corrected coordinates of the image of the mark calculated by using the method according to the present embodiment from the coordinates of the actual image of the mark. Also in FIG. 5B, the amount of deviation from the image of the mark at the time of no aberration to the image after the coordinate adjustment is magnified 100 times. As shown in FIG. 5B, it can be seen that the distortion is corrected and a distribution close to the original matrix arrangement is obtained.

As described above, by using the method according to the above embodiment, it is possible to correct the distortion of the lens and bring the coordinates of the mark image closer to the coordinates at the time of no aberration.

Next, with reference to FIGS. 6A to 6C and FIGS. 7A to 7D, distortion is corrected with high accuracy even when the optical axis of the image pickup apparatus 40 (FIG. 1) is tilted with respect to the surface of the object to be measured. Explain why you can.

6A and 6B show the image plane 41 when the optical axis of the image pickup apparatus 40 is perpendicular to the surface of the object to be measured, when it is assumed that there is no distortion and when it is assumed that there is distortion. It is a figure which shows the image of the mark in. The horizontal axis and the vertical axis of FIGS. 6A and 6B represent positions in the x-direction and the y-direction, respectively. Multiple marks are arranged at the grid points of the grid pattern. The image of the mark in FIGS. 6A and 6B is indicated by a circle symbol filled in black.

Assuming no distortion, the positions of the images of the plurality of marks coincide with the grid points of the square grid, as shown in FIG. 6A. Assuming that there is distortion, the position of the mark image deviates from the grid point as shown in FIG. 6B. In FIG. 6B, it is assumed that a barrel-shaped distortion that is significantly larger than the distortion of a general lens is generated.

FIG. 6C is a graph in which the relationship between the coordinate correction factor D _x in the x direction with respect to the diagonal direction of the image plane and the distance r from the center point of the image plane is plotted without distinguishing the four diagonal directions. be. Since distortion has a low dependence on the rotation direction centered on the center point of the image plane, a plurality of measurement points plotted in the four diagonal directions can be accurately approximated by one approximate curve. ..

7A and 7B show image planes when it is assumed that there is no distortion and when it is assumed that there is distortion when the optical axis of the image pickup apparatus 40 is inclined with respect to the surface of the object to be measured. It is a figure which shows the image of the mark in 41. The horizontal axis and the vertical axis of FIGS. 7A and 7B represent positions in the x-direction and the y-direction, respectively. Multiple marks are arranged at the grid points of the grid pattern. In FIGS. 7A and 7B, the image of the mark is indicated by a circle symbol filled in black.

Since the optical axis of 40 of the image pickup apparatus is tilted, as shown in FIG. 7A, the position of the mark image is deviated from the grid point even if it is assumed that there is no distortion. Since there is no distortion, the image of a straight line on the object to be measured becomes a straight line even in the image plane. For example, when the outer peripheral line of the region where a plurality of marks are distributed is square, the outer peripheral line of the region where the image of the marks is distributed in the image plane 41 becomes a trapezoid.

Assuming that the same aberration as the distortion aberration shown in FIG. 6B occurs with respect to the distribution of the mark image shown in FIG. 7A, the region where the mark image is distributed when it is assumed that there is distortion is shown in FIG. As shown in 7B, the shape is similar to that of a trapezoid and a barrel.

FIG. 7C shows the coordinate correction factor D _x in the x direction for the diagonal direction of the image surface 41 and the distance r from the center point of the image surface 41 without distinguishing the four diagonal directions of the image surface 41. It is a graph plotting the relationship between. Since the magnitude and direction of the distortion are different between the diagonal directions, the plotted measurement points are distributed in a wider range in the vertical axis direction as compared with the case shown in FIG. 6C. Even if one approximate curve is set for this distribution, the error between the coordinate correction factor obtained from the approximate curve and the coordinate correction factor at each measurement point is large.

FIG. 7D is a graph plotting the relationship between the coordinate correction factor D _x in the x direction with respect to the diagonal direction of the image plane 41 and the distance r from the center point of the image plane by distinguishing each of the sections Q1 to Q4. be. The squares, triangles, and circles in the graph are plotted for measurement points located on the diagonals of compartments Q2, Q3, and Q4, respectively. In addition, although the coordinate correction factor is calculated for a plurality of measurement points in the section Q1, the measurement points are not shown in FIG. 7D.

The thin broken line, the thin solid line, the thick broken line, and the thick solid line in the graph of FIG. 7D are approximate curves that approximate the distribution of the measurement points of the coordinate correction factors in the x direction for the sections Q1 to Q4, respectively. Focusing on one section, the error between the coordinate correction factor obtained from the approximate curve and the coordinate correction factor at a plurality of measurement points is small.

When the optical axis of the image pickup apparatus 40 is tilted with respect to the surface of the object to be measured, if the coordinates of the correction target portion are corrected based on one approximate curve shown in FIG. 7C, the position of the correction target location is corrected. Depending on the case, the error between the corrected coordinates and the coordinates when there is no aberration becomes large. On the other hand, in this embodiment, in step S1 (FIG. 4), of the four approximation curves shown in FIG. 7D, two approximation curves in which the coordinate correction factor at the correction target portion is more accurately reflected. Select.

Further, in step S2 (FIG. 4), the coordinate correction factor obtained from the two approximate curves is weighted averaged according to the degree to which the coordinate correction factor at the correction target portion is reflected. Therefore, even when the optical axis of the image pickup apparatus 40 is tilted with respect to the surface of the object to be measured, the coordinates are corrected using a coordinate correction factor close to the actual coordinate correction factor at the correction target location. be able to. Therefore, the correction accuracy of the coordinates can be improved.

Next, a modification of the above embodiment will be described.
In the above embodiment, the image plane 41 (FIG. 2) is divided into four sections Q1 to Q4, but the number of sections is not limited to four. The number of compartments may be two or more. For example, in the example shown in FIG. 7D, the approximate curves of the section Q1 and the section Q4 are close to each other, and the approximate curves of the section Q2 and the section Q3 are close to each other. Therefore, even if the section Q1 and the section Q4 are combined into one section and the section Q2 and the section Q3 are combined into one section, the correction accuracy of the coordinates can be maintained to some extent.

Further, in the above embodiment, the coordinate correction factors are obtained for the plurality of image points P1 (FIG. 2) on the diagonal lines of the four compartments Q1 to Q4, and _one approximate curve is obtained based on the coordinate correction factors. It is set. As a plurality of image points P1 that are the basis for setting an approximate curve, _one approximate curve is set in consideration of the coordinate correction factor at _other image points P1 in the section, not limited to the diagonal line. You may.

For example, the coordinate correction factor may be obtained for _a plurality of image points P1 in a region sandwiched in two radial directions from the reference point O toward the inside of one section. In this case, in order to set _one approximate curve that strongly reflects the coordinate correction factor at the plurality of image points P1 in the section, the area sandwiched between the two radial directions includes the geometric center of the section. It is advisable to set two radiation directions.

Further, in the above embodiment, when selecting two sections in step S1 (FIG. 4), the angle formed by the direction from the reference point O toward the correction target portion Pt is the smallest among the four boundary lines BL. Two sections on both sides of the boundary line BL are selected. In addition, two sections that closely approximate the coordinate correction factor at the correction target portion Pt may be selected.

For example, in the example shown in FIG. 7D, the approximate curve of the section Q1 and the approximate curve of the section Q4 show the same tendency with respect to the change of the distance r. This means that when the correction target portion Pt is located in the compartment Q1 or the compartment Q4, the coordinate correction factor in the correction target portion Pt is approximated with high accuracy in the compartment Q1 and the compartment Q4. Therefore, when the correction target portion Pt is located in the section Q1 or the section Q4, it is preferable to select the section Q1 and the section Q4 as the two sections in step S1 (FIG. 4). For the same reason, when the correction target portion Pt is located in the section Q2 or the section Q3, it is preferable to select the section Q2 and the section Q3 as the two sections in step S1 (FIG. 4).

Further, in the above embodiment, two sections are selected in step S1 (FIG. 4), but one section may be selected. For example, if the angle θ ₁ (FIG. 3) is 0 ° or small enough, only compartment Q1 may be selected. Whether to select one section or two sections may be determined based on the size of the angle θ ₁ .

Next, an inkjet drawing apparatus according to another embodiment will be described with reference to FIGS. 8A, 8B, and 9. The inkjet drawing apparatus according to the present embodiment is equipped with the distortion aberration correction apparatus according to the embodiments shown in FIGS. 1 to 4.

FIG. 8A is a schematic front view of the inkjet drawing apparatus 20. The movable table 25 is supported on the base 22 by the moving mechanism 24. It defines an xyz Cartesian coordinate system in which the x-axis and y-axis are oriented horizontally and the z-axis is vertically downward. The moving mechanism 24 is controlled by the control device 50 to move the movable table 25 in two directions, the x direction and the y direction. As the moving mechanism 24, for example, an XY stage including an X-direction moving mechanism 24X and a Y-direction moving mechanism 24Y can be used.

The substrate 80 to be drawn is held on the upper surface of the movable table 25. The substrate 80 is fixed to the movable table 25 by, for example, a vacuum chuck. The ink ejection unit 30 and the image pickup apparatus 40 are supported above the movable table 25 by, for example, a gate-shaped support member 23.

The image pickup apparatus 40 images the upper surface of the substrate 80. More specifically, the area within the image field of the image pickup apparatus 40 is imaged on the upper surface of the substrate 80. The image obtained by the image pickup device 40 is input to the distortion aberration correction processing device 10.

The control device 50 receives the position information of the substrate 80 from the distortion aberration correction processing device 10. By controlling the moving mechanism 24 and the ink ejection unit 30 based on this position information, the ink is landed at a predetermined position on the surface of the substrate 80. As a result, an ink film having a predetermined shape is formed on the surface of the substrate 80.

FIG. 8B is a diagram showing the positional relationship of the movable table 25, the ink ejection unit 30, and the image pickup apparatus 40 in a plan view. The substrate 80 is held on the upper surface of the movable table 25. The ink ejection unit 30 and the image pickup apparatus 40 are supported above the substrate 80. A plurality of nozzles 32 are provided on the surface of the ink ejection unit 30 facing the substrate 80. The control device 50 controls the moving mechanism 24 to move the movable table 25 in the x-direction and the y-direction, and controls the ejection of ink from each nozzle 32 of the ink ejection unit 30.

Alignment marks 81 are formed at the four corners of the substrate 80, respectively. The control device 50 operates the moving mechanism 24 to arrange each of the alignment marks 81 within the image field of the image pickup device 40, so that the image pickup device 40 can image the alignment mark 81.

FIG. 9 is a flowchart showing a procedure for drawing with an inkjet drawing device. First, the control device 50 operates the moving mechanism 24 to move one alignment mark 81 within the image field of the image pickup device 40 (step S11). After that, the image pickup apparatus 40 takes an image of the alignment mark 81 (step S12). The captured image data is input to the distortion aberration correction processing device 10. The distortion aberration correction processing device 10 detects the coordinates in the image plane of the image of the alignment mark 81 by analyzing the image of the alignment mark 81 (step S13). A known algorithm such as pattern matching can be used to detect the coordinates of the image of the alignment mark 81.

The distortion aberration correction processing device 10 corrects the coordinates of the image of the alignment mark 81 by executing the procedure according to the embodiment shown in FIG. 4 (step S14). The procedure from step S11 to step S14 is repeated until the coordinates of all the alignment marks 81 are corrected (step S15).

When the correction of the coordinates of all the alignment marks 81 is completed, the distortion aberration correction processing device 10 delivers the corrected coordinates of the image of the alignment marks 81 to the control device 50 (FIGS. 8A and 8B) (step S16). The control device 50 executes the drawing process based on the corrected coordinates of the image of the alignment mark 81 (step S17).

Next, the excellent effect of this embodiment will be described.
Since the inkjet drawing apparatus according to this embodiment is equipped with the distortion aberration correction processing apparatus 10 shown in FIGS. 1 to 4, the position of the alignment mark 81 can be measured with high accuracy. In particular, even when the optical axis of the image pickup apparatus 40 is tilted with respect to the surface of the substrate 80, it is possible to suppress a decrease in measurement accuracy of the position of the alignment mark 81.

Next, a modification of the embodiment shown in FIGS. 8A to 9 will be described. In the embodiments shown in FIGS. 8A to 9, the distortion aberration correction processing apparatus 10 according to the embodiments shown in FIGS. 1 to 4 is mounted on the inkjet drawing apparatus, but the embodiments shown in FIGS. 1 to 4 are provided. The distortion aberration correction processing device 10 can be mounted on other devices. For example, it can be mounted on a laser processing device that performs drilling by incident a laser beam on an object, a laser annealing device that performs annealing by incident a laser beam on a semiconductor substrate that is an object, and the like.

It goes without saying that each of the above embodiments is exemplary and the configurations shown in different examples can be partially replaced or combined. Similar actions and effects due to the same configuration of a plurality of examples will not be mentioned sequentially for each example. Furthermore, the present invention is not limited to the above-mentioned examples. For example, it will be obvious to those skilled in the art that various changes, improvements, combinations, etc. are possible.

10 Distortion correction processing device 11 Input / output interface unit 12 Processing unit 13 Storage unit 14 Program 15 Distortion correction information 20 Inkjet drawing device 22 Base 23 Support member 24 Movement mechanism 24XX direction movement mechanism 24Y Y direction movement mechanism 25 Movable table 30 Ink ejection unit 32 Nozzle 40 Imaging device 41 Image plane of imaging device 50 Control device 80 Board 81 Alignment mark

Claims (5)

The relationship between the coordinate correction factor for correcting the coordinates on the image plane and the distance from the reference point for each of the plurality of sections divided by the plurality of boundaries extending radially from the reference point on the image plane of the image pickup apparatus. A storage unit that stores the distortion correction information shown, and
At least one section is selected from the plurality of sections based on the coordinates of the correction target portion in the image plane, the distortion aberration correction information for the selected section, and the distance from the reference point to the correction target location. A distortion aberration correction processing device including a processing unit that determines a coordinate correction factor based on the above and corrects the coordinates of the correction target portion based on the determined coordinate correction factor. The shape of the image plane is square or rectangular and
The reference point is located at the center of the image plane and
The distortion aberration correction processing device according to claim 1, wherein the plurality of boundary lines are four line segments connecting the center of the image plane and the midpoint of each of the four sides. The processing unit is in the process of correcting the coordinates of the correction target portion.
Of the plurality of boundary lines, two sections on both sides of the boundary line having the smallest angle from the reference point to the correction target portion are selected.
The distortion correction for the two selected sections based on the angle between the reference point and the direction toward the geometric center of each of the two selected sections and the direction from the reference point toward the correction target location. The distortion correction processing device according to claim 1 or 2, wherein the coordinate correction factor of information is weighted and averaged, and the coordinates of the correction target portion are corrected based on the weighted averaged coordinate correction factor. The relationship between the coordinate correction factor that corrects the coordinates in the image and the distance from the reference point for each of the plurality of sections divided by the plurality of boundaries extending radially from the reference point in the image plane of the image pickup apparatus. Using an image pickup device whose distortion aberration correction information is known, an image of the object to be measured is imaged.
The correction target location for correcting the coordinates in the image plane is determined, and the correction target location is determined.
At least one section is selected from the plurality of sections based on the position of the correction target portion in the image plane.
The coordinate correction factor is determined based on the distortion correction information for the selected section and the distance from the reference point to the correction target location.
A distortion aberration correction method for correcting the coordinates of the correction target portion based on the determined coordinate correction factor. The relationship between the coordinate correction factor that corrects the coordinates in the image and the distance from the reference point for each of the plurality of sections divided by the plurality of boundaries extending radially from the reference point in the image plane of the image pickup apparatus. The procedure for acquiring an image of a measurement object captured by an image pickup device whose distortion aberration correction information is known, and
A procedure for determining a correction target portion to be corrected from an image captured by the image pickup device, and
A procedure for selecting at least one section from the plurality of sections based on the coordinates of the correction target portion in the image plane, and a procedure for selecting at least one section from the plurality of sections.
A procedure for determining the coordinate correction factor based on the distortion correction information for the selected section and the distance from the reference point to the correction target location.
A program that causes a computer to execute a procedure for correcting the coordinates of the correction target portion based on the determined coordinate correction factor.

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