Stage system and stage calibration method

Abstract

This system provides a stage system and a stage calibration method that can acquire and correct the amount of correction for the direction of rotation that occurs due to movement in a plane parallel to the direction of stage movement. [Solution] This stage system 100 is configured to perform the following actions at multiple moving points of the stage 1: control to acquire the coordinates of two calibration marks M, one mark M1 and the other mark M2, which are two of the multiple calibration marks M, for each movement; and control to acquire a θ correction amount to correct for the rotation angle deviation on a plane parallel to the mounting surface 11, based on the acquired coordinates of one mark M1, the other coordinate C1, and the other coordinate C2, which are the coordinates of the other mark M2, and the ideal coordinates when no deviation occurs due to the movement of the stage.

Description

Technical Field

[0001] The present invention relates to a stage system and a method for calibrating a stage, and more particularly to a stage system including an imaging unit and a method for calibrating a stage.

Background Art

[0002] Conventionally, a stage system including an imaging unit and a method for calibrating a stage have been known (see, for example, Patent Document 1).

[0003] In Patent Document 1 mentioned above, a movement amount correction device (stage system) for an XY stage including a camera as an imaging unit is disclosed. In this movement amount correction device (stage system), a flat panel display on a flat plate is placed on the XY stage, and correction information on the movement amount of the XY stage is obtained by imaging, with a camera, the pixels that are lit and displayed on the flat panel display. Specifically, in Patent Document 1, the display pixels of the flat panel display arranged in a matrix in the X-axis direction and the Y-axis direction are lit, and the lit display pixels are imaged with a camera every time the XY stage moves, thereby obtaining correction information for correcting the deviation of the movement amount of the XY stage. In Patent Document 1, it is possible to correct (calibrate) the deviation of the movement amount of the XY stage with an accuracy comparable to the arrangement interval of the display pixels of the flat panel display.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the displacement of the XY stage may include not only components in the X-axis and Y-axis directions but also components of rotation within the XY plane. In the above-mentioned Patent Document 1, even if there is a component of rotation within the XY plane, the rotation component is obtained as displacement in the X-axis and Y-axis directions, and the correction of the rotation component is also performed as a translation within the XY plane. In other words, since it is not possible to correct all of the displacement of the rotation component within the XY plane by translation within the XY plane, the displacement of the XY stage is corrected for a predetermined point within the XY plane by translation within the XY plane. Therefore, in an XY stage that moves a mounting surface of a certain size, if the displacement on the mounting surface due to the movement of the XY stage is corrected for a predetermined point on the mounting surface by translation within the XY plane, the mounting surface remains rotated due to the movement of the stage even after the displacement of the XY stage has been corrected. For this reason, displacement due to the rotation component within the XY plane occurs at points other than the predetermined point. Furthermore, as the distance from a predetermined point increases, the influence of the rotational component in the XY plane also increases. Therefore, relatively large rotational component deviations occur in parts of the mounting surface that are a considerable distance from a predetermined point. For this reason, there is a need for a stage system and a stage calibration method that can compensate for rotational deviations caused by stage movement in a plane parallel to the direction of stage movement.

[0006] This invention was made to solve the above-mentioned problems, and one object of this invention is to provide a stage system and a stage calibration method that can correct rotational deviations caused by the movement of the stage in a plane parallel to the direction of movement of the stage. [Means for solving the problem]

[0007] To achieve the above objective, the stage system according to this first phase comprises a stage on which a mounting surface on which a substrate is placed or a calibration substrate placed on the mounting surface has a plurality of calibration marks arranged at predetermined intervals, and the mounting surface is configured to be movable in a direction parallel to the mounting surface and rotatable within a plane parallel to the mounting surface; an imaging unit for imaging the calibration marks; an imaging unit movement mechanism for moving the imaging unit in a direction parallel to the mounting surface; and a control unit for acquiring the coordinates of the calibration marks based on the image of the calibration marks and the amount of movement of the imaging unit movement mechanism when the image is captured. The control unit is configured to perform the following actions during stage calibration: control to move the stage in a direction parallel to the mounting surface; control to acquire the coordinates of two of the plurality of calibration marks at each movement point of the stage; control to acquire a θ correction amount to correct the deviation of the rotation angle in the plane parallel to the mounting surface, and control to acquire an XY correction amount to correct the deviation in the direction parallel to the mounting surface, based on the acquired coordinates of the two calibration marks and the ideal coordinates when there is no deviation in the movement of the stage.

[0008] As described above, the stage system in this first phase is configured to perform the following actions at multiple movement points of the stage: acquiring the coordinates of two of the multiple calibration marks for each movement; and acquiring a θ correction amount to correct for the deviation in the rotation angle on a plane parallel to the mounting surface, based on the acquired coordinates of the two calibration marks and the ideal coordinates when no deviation occurs due to the stage movement. In other words, by acquiring the coordinates of two points, information about the line segment connecting the two points can be obtained, and thus information about the line segment formed by two of the calibration marks can be obtained from the coordinates of the two calibration marks after the actual stage movement. Furthermore, information about the line segment formed by two points in the ideal coordinates corresponding to the acquired coordinates can be obtained from the ideal coordinates of two points when no deviation occurs due to the stage movement. This makes it possible to calculate the angle between the line segment formed by two of the calibration marks and the line segment formed by two points in the ideal coordinates corresponding to the acquired coordinates. This calculated angle can be obtained as a θ correction amount, which is the deviation in the rotational angle caused by the stage movement in a plane parallel to the mounting surface of the calibration substrate. As a result, the deviation in the rotational direction caused by the stage movement in a plane parallel to the direction of stage movement can be corrected using the θ correction amount.

[0009] In the stage system according to the first aspect described above, preferably, the control unit is configured to perform control to acquire the XY correction amount based on the θ correction coordinate obtained by correcting the angular deviation of the stage's θ correction amount for one of the coordinates of the two acquired calibration marks, and the ideal coordinate in the case where no deviation occurs due to the movement of the stage. With this configuration, the XY correction amount can be acquired while correcting the rotation angle deviation based on the θ correction amount, which is the rotation angle deviation caused by the movement of the stage. As a result, the XY correction amount can be acquired over the entire stage while reducing the influence of the rotational direction deviation caused by the movement of the stage.

[0010] In this case, preferably, the control unit is configured to either rotate the stage in the rotation direction that corrects the θ correction amount, and then perform control to acquire coordinates again from the calibration mark from which one coordinate was acquired, thereby obtaining θ-corrected coordinates that have been corrected for the angular deviation of the θ correction amount due to rotation around the rotation axis of the stage, or, if the coordinates of the rotation axis of the stage have been acquired in advance, perform a calculation to rotate one coordinate around the rotation axis of the stage by the amount of the θ correction, thereby obtaining θ-corrected coordinates that have been corrected for the angular deviation of the θ correction amount due to rotation around the rotation axis of the stage. With this configuration, θ-corrected coordinates that have been corrected for the rotation angle deviation based on the θ correction amount can be obtained by actually rotating the stage, or by performing a calculation based on the rotation axis coordinate that has been acquired in advance. Furthermore, since the XY correction amount for correcting deviation in the direction parallel to the mounting surface can be obtained simply by obtaining the difference between the θ-corrected coordinates that have been corrected for the angular deviation of the θ correction amount and the ideal coordinates, the XY correction amount can be obtained more easily while reducing the influence of deviation in the rotation direction caused by the movement of the stage.

[0011] In the stage system according to the first aspect described above, preferably, the control unit is configured to correct the amount of movement of the imaging unit movement mechanism using a calibration mark before performing control to acquire the θ correction amount and the XY correction amount, and the distance between the calibration mark and the imaging unit when correcting the amount of movement of the imaging unit movement mechanism is configured to be the same as the distance between the calibration mark and the imaging unit when acquiring the θ correction amount and the XY correction amount. With this configuration, since the distance between the calibration mark and the imaging unit when correcting the amount of movement of the imaging unit movement mechanism is the same as the distance between the calibration mark and the imaging unit when acquiring the θ correction amount and the XY correction amount, even if the optical axis of the imaging unit is not perpendicular to the mounting surface of the stage, there is no discrepancy between the coordinates of the calibration mark acquired during imaging unit calibration and the coordinates of the calibration mark acquired during stage calibration in the direction parallel to the mounting surface. As a result, the coordinates acquired during imaging unit calibration and the coordinates acquired during stage calibration can be made to coincide in the direction parallel to the mounting surface.

[0012] In this case, preferably, multiple stages are provided, and the multiple stages are arranged so as to overlap in a direction perpendicular to the mounting surface when in use, and the coordinates in the direction parallel to the mounting surface are configured to coincide among the multiple stages, and the θ correction amount and XY correction amount for each stage are obtained when the distance between the calibration mark and the imaging unit is equal during the calibration of each of the multiple stages. With this configuration, even if the optical axis of the imaging unit is not perpendicular to the mounting surface of the multiple stages when multiple stages are provided, the coordinates obtained during the calibration of each of the multiple stages can be made to coincide in the direction parallel to the mounting surface.

[0013] In the stage system according to the first aspect described above, preferably, in the control for acquiring the coordinates of two of a plurality of calibration marks each time the stage moves, the imaging unit is configured to move to detect the same two calibration marks at multiple moving points of the stage, and to acquire the coordinates of the same two calibration marks at multiple moving points of the stage. With this configuration, the imaging unit moves to detect the same two calibration marks at multiple moving points of the stage, and acquires the coordinates of the same two calibration marks before and after the stage movement, so that the coordinates of the calibration marks for each stage movement can be acquired based on the movement of the imaging unit. As a result, the stage can be calibrated at any interval, without depending on the interval between adjacent calibration marks. In addition, since the same two calibration marks are detected at multiple moving points of the stage, the imaging unit will image the same two calibration marks. Since the imaging unit images the same two calibration marks, it is possible to prevent calibration errors caused by errors in the shape of each calibration mark and errors in the placement position of the calibration marks.

[0014] In the stage system according to the first aspect described above, preferably, one imaging unit is provided, and at multiple moving points, the imaging unit is configured to acquire the coordinates of one of the two calibration marks by imaging one of the two calibration marks, and then, by moving, detect the other of the two calibration marks, the other mark, and acquire the coordinates of the other mark by imaging it. With this configuration, since the other mark is detected and imaged by the movement of the imaging unit, the coordinates of the other mark can be acquired without moving the stage. As a result, since there is no rotational deviation caused by the rotation associated with the movement of the stage in order to acquire the coordinates of the other mark, the θ correction amount of the stage can be acquired more accurately.

[0015] In the stage system according to the first aspect described above, preferably, when correcting the stage movement again after calibration based on the XY correction amount, the system is configured to perform the following controls: acquire the calibration mark coordinates, which are the coordinates of the calibration mark, for each of the multiple movement points during the correction of the stage movement again, by moving the mounting surface in a direction parallel to the mounting surface with the stage and imaging the calibration mark with the imaging unit; acquire the XY correction amount during the correction based on the calibration mark coordinates during the correction obtained for each of the multiple movement points during the correction; acquire the XY correction amount during the correction based on the calibration mark coordinates during the correction obtained for each of the multiple movement points during the correction and the instruction value, which is a value used to instruct the movement of the stage at each of the multiple movement points during the correction; acquire a conversion formula to convert the multiple XY correction amounts during the correction obtained for each of the multiple movement points during the correction of the correction, so that they are minimized; and acquire a corrected XY correction amount based on the XY correction amount at each of the multiple movement points and the conversion formula. With this configuration, the XY correction amount for recalibration is obtained based on the coordinates of the calibration marks acquired for each of the multiple recalibration movement points, and the instruction values ​​used for instructing the movement of the stage at each of the multiple recalibration movement points. Therefore, one imaging operation (acquisition of calibration mark coordinates) is performed by the imaging unit to acquire one XY correction amount for recalibration. In other words, the XY correction amount for recalibration can be acquired in a shorter time than the XY correction amount. Furthermore, the XY correction amount can be converted to a corrected XY correction amount using a conversion formula acquired based on the XY correction amount for recalibration, and the recalibration of the stage movement after calibration can be performed. As a result, the recalibration of the stage movement after calibration can be performed in a shorter time than by acquiring the XY correction amount for recalibration and performing calibration.

[0016] A calibration method for a stage configured to be movable, wherein a plurality of calibration marks are arranged at predetermined intervals on a mounting surface on which a substrate is placed or on a calibration substrate placed on the mounting surface, comprises the steps of: moving a stage configured to be movable in a direction parallel to the mounting surface; acquiring the coordinates of two of the plurality of calibration marks at multiple moving points of the stage for each movement; acquiring a θ correction amount to correct the rotation angle deviation on a plane parallel to the mounting surface based on the coordinates of the two acquired calibration marks and the ideal coordinates when no deviation occurs due to the movement of the stage; and acquiring an XY correction amount to correct the deviation in the direction parallel to the mounting surface.

[0017] The second stage calibration method, as described above, includes the steps of: acquiring the coordinates of two of the multiple calibration marks for each movement; and acquiring a θ correction amount to compensate for the rotation angle deviation on a plane parallel to the mounting surface, based on the coordinates of the two acquired calibration marks and the ideal coordinates when no deviation occurs due to the stage movement. In other words, by acquiring the coordinates of two points, information about the line segment connecting the two points can be obtained, and thus information about the line segment composed of two points among the calibration marks can be obtained from the coordinates of the two calibration marks after the actual stage movement. Furthermore, information about the line segment composed of two points in the ideal coordinates corresponding to the acquired coordinates can be obtained from the ideal coordinates of two points when no deviation occurs due to the stage movement, respectively. This makes it possible to calculate the angle between the line segment composed of two points among the calibration marks and the line segment composed of two points in the ideal coordinates corresponding to the acquired coordinates. This calculated angle can be acquired as a θ correction amount, which is the deviation in the rotation angle caused by the stage movement on a plane parallel to the mounting surface of the calibration substrate. As a result, a stage calibration method can be provided that uses a θ correction amount to correct rotation caused by the movement of the stage in a plane parallel to the direction of stage movement. [Effects of the Invention]

[0018] According to the present invention, as described above, it is possible to provide a stage system and a stage calibration method that can correct rotational deviations caused by the movement of the stage in a plane parallel to the direction of stage movement. [Brief explanation of the drawing]

[0019] [Figure 1] This is a schematic diagram showing a stage system according to the first embodiment of the present invention. [Figure 2]An example of a captured image by the imaging unit of the first embodiment. [Figure 3] A schematic diagram for explaining the correction of the movement amount of the imaging unit movement mechanism of the first embodiment. [Figure 4] A schematic diagram for explaining the coordinate deviation when the height of the stage in the stage system of the first embodiment of the present invention changes. [Figure 5] A flowchart showing the processing of the stage calibration method in the stage system according to the first embodiment of the present invention. [Figure 6] A schematic diagram showing the state of the stage before movement in the stage system according to the first embodiment of the present invention. [Figure 7] A schematic diagram showing the state where the stage according to the first embodiment of the present invention is moved and the imaging unit is moved to image the calibration mark. [Figure 8] A schematic diagram showing the state where the imaging unit is moved to image the second calibration mark after the stage is moved in the stage system according to the first embodiment of the present invention. [Figure 9] A schematic diagram for explaining the acquisition of the deviation of the stage in the rotational direction in the stage system of the first embodiment of the present invention. [Figure 10] A schematic diagram for explaining the acquisition of the coordinates of the calibration mark in the state where the deviation of the stage in the rotational direction is corrected in the stage system of the first embodiment of the present invention. [Figure 11] A schematic diagram for explaining the acquisition of the deviation in the XY direction in the state where the deviation of the stage in the rotational direction is corrected in the stage system of the first embodiment of the present invention. [Figure 12] A schematic diagram showing the stage system of the second embodiment of the present invention. [Figure 13] A schematic diagram for explaining the coordinate deviation between two stages in the stage system of the second embodiment of the present invention. [Figure 14]This is a flowchart illustrating the calibration method for recalibrating the stage in a stage system according to a third embodiment of the present invention. [Figure 15] (a) A schematic diagram showing the state of the stage before movement in the stage system according to the third embodiment of the present invention. (b) A diagram showing the captured image at the origin O before the stage moves. [Figure 16] (a) A schematic diagram showing the state after the stage according to the third embodiment of the present invention. (b) A diagram showing the image captured at the origin O after the stage has been moved. [Figure 17] This is a schematic diagram illustrating the movement of the imaging unit in a stage system according to a third embodiment of the present invention. [Figure 18] This is a schematic diagram illustrating the XY correction amount map generated during recorrection in the stage system of the third embodiment of the present invention. [Figure 19] This is a schematic diagram illustrating the post-correction map obtained by transforming the XY correction amount map during re-correction for acquiring the transformation matrix in the stage system of the third embodiment of the present invention. [Modes for carrying out the invention]

[0020] The following describes embodiments of the present invention based on the drawings.

[0021] [First Embodiment] The configuration of the stage system 100 according to the first embodiment of the present invention will be described with reference to Figures 1 to 11.

[0022] (Stage system configuration) As shown in Figure 1, the stage system 100 according to the first embodiment is configured to perform calibration of the stage 1 based on an image I (see Figure 2) captured by the imaging unit 2 of calibration marks M placed on the calibration substrate S which is placed on the mounting surface 11 on which the substrate of the stage 1 is placed.

[0023] As shown in Figure 1, the stage system 100 according to the first embodiment comprises a stage 1, an imaging unit 2, an imaging unit movement mechanism 3, and a control unit 4. In this specification, the left-right direction of the stage system 100 (one direction parallel to the mounting surface 11) is defined as the X direction. The up-down direction of the stage system 100 (a direction perpendicular to the mounting surface 11) is defined as the Z direction. The direction parallel to the mounting surface 11 that is perpendicular to the X and Z directions is defined as the Y direction.

[0024] Stage 1 is configured to have a mounting surface 11 on which a substrate is placed, which is movable in a direction parallel to the mounting surface 11 and rotatable within a plane parallel to the mounting surface 11. For example, Stage 1 includes an X-axis stage 12 configured to be movable in the X direction and driven by a motor, a Y-axis stage 13 configured to be movable in the Y direction, a Z-axis stage 14 configured to be movable in the Z direction, and a θ-axis stage 15 configured to be rotatable within a plane parallel to the mounting surface 11.

[0025] During the calibration of Stage 1, the calibration substrate S is placed on the mounting surface 11 of Stage 1. Multiple calibration marks M are arranged on the calibration substrate S at predetermined intervals. For example, the calibration substrate S is a substrate with a grid pattern, and the calibration marks M are grid points of the grid pattern. For example, the spacing W between the grid points is 1 mm.

[0026] The imaging unit 2 is configured to capture images of the calibration marks M on the calibration substrate S placed on the mounting surface 11 of the stage 1. For example, the imaging unit 2 is a two-dimensional camera.

[0027] The imaging unit movement mechanism 3 is configured to move the imaging unit 2 in a direction parallel to the mounting surface 11 of the stage 1. For example, the imaging unit movement mechanism 3 includes an imaging unit X-axis stage 31 configured to move the imaging unit 2 in the X direction, which is driven by a motor, and an imaging unit Y-axis stage 32 configured to move the imaging unit 2 in the Y direction.

[0028] The control unit 4 is configured to control the stage 1, the imaging unit 2, and the imaging unit movement mechanism 3. For example, the control unit 4 is a computer that includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), GPU (Graphics Processing Unit), etc., as a processor, enabling control processing and calculation processing of the equipment.

[0029] Furthermore, as shown in Figure 2, the control unit 4 acquires the coordinates of the calibration mark M based on the captured image I of the calibration mark M and the amount of movement of the imaging unit movement mechanism 3 when the captured image I is taken. Specifically, the control unit 4 detects the calibration mark M in the captured image I that matches a pre-registered image of the calibration mark M by performing image processing on the captured image I. Since the coordinates of the field of view center Ce of the imaging unit 2 can be calculated from the amount of movement of the imaging unit movement mechanism 3, the coordinates of the calibration mark M can be acquired based on the field of view center Ce of the imaging unit 2 and the detection position of the calibration mark M in the captured image I.

[0030] Furthermore, the control unit 4 is configured to correct the amount of movement of the imaging unit movement mechanism 3 using the calibration mark M before performing the control to acquire the θ correction amount and the XY correction amount. The correction of the amount of movement of the imaging unit movement mechanism 3 will be explained with reference to Figure 3.

[0031] As shown in Figure 3, in correcting the amount of movement of the imaging unit movement mechanism 3, first, the θ-axis stage 15 is rotated to adjust the position of the calibration marks M so that they are aligned with the X and Y axes.

[0032] Figure 3 shows how the imaging unit 2 is sequentially moved along the positive Y-axis from the coordinate origin O, and a calibration mark M is captured each time the imaging unit 2 moves.

[0033] The control unit 4 instructs the imaging unit movement mechanism 3 to move the imaging unit 2 in the Y direction by the distance W between the calibration marks M. If the movement of the imaging unit 2 is performed ideally, the field of view center Ce of the imaging unit 2 will start from a state where it coincides with the calibration mark M at the coordinate origin O, and the field of view center Ce of the imaging unit 2 will move to coincide with the calibration marks M aligned in the Y direction with each movement instruction. However, until the amount of movement of the imaging unit movement mechanism 3 is corrected, the instructed value, which is the distance that the control unit 4 instructs the imaging unit movement mechanism 3 to move the imaging unit 2, will not necessarily match the actual movement distance of the imaging unit 2. Therefore, until the amount of movement of the imaging unit movement mechanism 3 is corrected, as shown in Figure 3, the field of view center Ce of the imaging unit 2 may be in a position shifted from the calibration mark M with each movement. The shift between the calibration mark M and the field of view center Ce of the imaging unit 2 at this time is obtained as the correction amount for the imaging unit movement mechanism 3. In Figure 3, the position of the imaging unit 2 on the calibration substrate S is represented as the imaging unit position P. Furthermore, in Figures 3 and 6-11, the origin O was taken as shown in the figures for the sake of explanation, but the origin O may also be taken so that it coincides with the center position of the correction range.

[0034] Here, if the control unit 4 instructs the imaging unit 2 to move from the origin O along the positive Y-axis to the next calibration mark M, that is, if it instructs the imaging unit 2 to move by an interval W in the Y-axis direction, for example, the actual amount of movement of the imaging unit 2 by the imaging unit movement mechanism 3 is -dX in the X-axis direction and W-dY in the Y-axis direction. Therefore, in order to move the imaging unit 2 by an interval W in the Y-axis direction, it is necessary to instruct an additional movement of dX in the X-axis direction and an additional movement of dY in the Y-axis direction. Accordingly, for the section from the origin O to the adjacent calibration mark M in the positive Y-axis direction, dX is obtained as the correction value in the X-axis direction and dY is obtained as the correction value in the Y-axis direction.

[0035] The amount of movement of the imaging unit movement mechanism 3 is corrected based on the interval W between the calibration marks M. Furthermore, since the correction amount for the movement of the imaging unit movement mechanism 3 can only be obtained for each interval W between the calibration marks M, the correction amount for movement less than or equal to the interval W between the calibration marks M is obtained, for example, by apportioning the acquired correction amount for movement according to the amount of movement of the imaging unit movement mechanism 3. Specifically, for distances w less than or equal to the interval W between the calibration marks M, the correction amount is obtained by multiplying the value obtained by dividing w by W by dX and dY.

[0036] Normally, the optical axis of the imaging unit 2 is adjusted to be perpendicular to the mounting surface 11. However, as shown in Figure 4, there are cases where the optical axis of the imaging unit 2 is not perpendicular to the mounting surface 11. In this case, if the amount of movement of the imaging unit movement mechanism 3 is corrected by a predetermined height Z0 in the Z-axis direction, the control unit 4 acquires coordinates based on the position information acquired at height Z0.

[0037] For example, as shown in Figure 4, the control unit 4 obtains coordinates Ca from the calibration mark M on the calibration substrate S at height Z0. As described above, the coordinates of the calibration mark M are obtained based on the amount of movement of the imaging unit 2 from the origin O and the captured image I. Therefore, if the optical axis of the imaging unit 2 is not perpendicular to the mounting surface 11, and the calibration of Stage 1 described later is performed at a height Z1 different from the height Z0 at which the movement amount of the imaging unit movement mechanism 3 was corrected, the imaging unit 2 will capture different points on the XY plane while remaining in the same position. Consequently, since the control unit 4 obtains coordinates Ca from the calibration mark M, which is actually coordinate Cb on the calibration substrate S at height Z1, there is a discrepancy between the coordinates obtained when acquiring the correction amount of the imaging unit movement mechanism 3 and the coordinates obtained when performing the calibration of Stage 1.

[0038] Therefore, in order to prevent a discrepancy between the coordinates when acquiring the correction amount of the imaging unit movement mechanism 3 and the coordinates when calibrating the stage 1, the mounting surface 11 is moved in the Z direction using the Z-axis stage 14, so that the distance between the calibration mark M when acquiring the correction amount of the imaging unit movement mechanism 3 and the imaging unit 2 is equal to the distance between the calibration mark M and the imaging unit 2 when acquiring the θ correction amount and the XY correction amount. Regarding the calibration of the imaging unit 2, the imaging field of view of the imaging unit 2 is 1 mm 2 Because the field of view is narrow and the calibration mark M is imaged near the center Ce of the imaging unit 2, the effect of rotational displacement due to the movement of the imaging unit 2 can be ignored. Therefore, it is not necessary to consider the θ correction amount to compensate for the rotational angle displacement, as in the calibration of Stage 1 described later.

[0039] (Stage calibration method) Next, with reference to Figures 5 to 9, the calibration method for Stage 1 in the Stage System 100 in the first embodiment will be described. Here, in Figures 6 to 11, the dashed lines arranged in a grid are provided for the convenience of explanation and represent the ideal coordinate Ci, which is the position of the calibration mark M when Stage 1 moves in the X-axis or Y-axis direction without any displacement associated with the movement of Stage 1. Note that in Figure 6, the positions of the calibration substrate S and the ideal coordinate Ci overlap, so they are slightly offset for the convenience of drawing. In Figures 6 to 11, the ideal coordinate Ci represents the position of the ideal calibration mark M when Stage 1 is moved in the positive Y-axis direction by the amount indicated for Stage 1. For example, Stage 1 is calibrated by moving Stage 1 by the same indicated amount. Also, in Figures 6 to 11, the position of the imaging unit 2 on the calibration substrate S is represented as the imaging unit position P.

[0040] In step S1 shown in Figure 5, as shown in Figure 6, the control unit 4 rotates the θ-axis stage 15 and adjusts the position of the calibration marks M so that they are aligned with the X and Y axes. Then, the process proceeds to step S2.

[0041] In step S2 shown in Figure 5, as shown in Figure 7, the control unit 4 controls the stage 1 to move in a direction parallel to the mounting surface 11 during the calibration of the stage 1. Figure 7 shows the state after the control unit 4 controls the stage 1 to move in the Y-axis direction by the specified value, starting from the state in Figure 6. Due to the movement of the stage 1, a discrepancy occurs between the position of the calibration mark M and the grid point of the ideal coordinate Ci. The process then proceeds to step S3.

[0042] In steps S3 and S4 shown in Figure 5, the control unit 4 performs control to acquire, for each movement, two of the calibration marks M, namely one mark M1 (coordinate C1) and the other mark M2 (coordinate C2), which are two of the calibration marks M, at multiple movement points of Stage 1. In the first embodiment, at multiple movement points of Stage 1, the coordinates of two identical calibration marks M, namely one mark M1 and the other mark M2, are acquired from among the multiple calibration marks M. In other words, two marks are selected from among the multiple calibration marks M on the calibration substrate S, and at multiple movement points, coordinates are acquired from the two selected calibration marks M, namely one mark M1 and the other mark M2.

[0043] Specifically, in step S3 shown in Figure 5, as shown in Figure 7, in the control to acquire one coordinate C1, which is the coordinate of one of the multiple calibration marks M1, and the other coordinate C2, which is the coordinate of the other mark M2, with each movement of stage 1, the control unit 4 controls the movement of the imaging unit 2 by the same amount as the instruction value for the movement of stage 1. That is, the imaging unit position P moves so that the center of the field of view Ce of the imaging unit 2 is at the position of the ideal coordinate Ci1 corresponding to one mark M1, assuming there was no displacement due to the movement of stage 1. By controlling the movement of the imaging unit 2, the imaging unit position P moves to a position where one mark M1 can be detected. As a result, after the movement of stage 1, the one coordinate C1 after the movement of stage 1 is acquired. Then, the process proceeds to step S4.

[0044] In step S4 shown in Figure 5, as shown in Figure 8, the control unit 4 controls the movement of the imaging unit 2 after it has acquired the coordinates of one of the two calibration marks M1 by imaging the imaging unit 2. That is, the imaging unit position P moves to the position of the ideal coordinate Ci2 corresponding to the other mark M2, assuming that there was no displacement caused by the movement of the stage 1 at the center of the imaging unit 2's field of view Ce. By controlling the movement of the imaging unit 2, the imaging unit position P moves to a position where the other mark M2 can be detected.

[0045] Furthermore, in step S4 shown in Figure 5, the other mark M2 of the two calibration marks M is detected and its coordinates are obtained by imaging the other mark M2. After that, the process proceeds to step S5.

[0046] In step S5 shown in Figure 5, as shown in Figure 9, the control unit 4 is configured to perform control to acquire a θ correction amount to correct the rotation angle deviation on a plane parallel to the mounting surface 11, based on the acquired one-sided coordinate C1 of one-sided mark M1, the acquired other-sided coordinate C2 of the other-sided mark M2, and the ideal coordinate Ci, which is the ideal coordinate when no displacement occurs due to the movement of the stage 1. Specifically, as shown in Figure 9, the angle formed by the line segment L composed of one-sided mark M1 and the other-sided mark M2, calculated based on the one-sided coordinate C1 and the other-sided coordinate C2, and the line segment Li calculated from the ideal coordinate Ci1 corresponding to one-sided mark M1 and the ideal coordinate Ci2 corresponding to the other-sided mark M2, which is the ideal coordinate Ci when there is no displacement due to the movement of the stage 1, becomes the θ correction amount to correct the rotation angle deviation on a plane parallel to the mounting surface 11.

[0047] In steps S6 to S8 shown in Figure 5, the control unit 4 is configured to perform control to acquire an XY correction amount to correct the misalignment in the direction parallel to the mounting surface 11.

[0048] Specifically, in step S6 shown in Figure 5, the control unit 4 is configured to rotate the stage 1 in the rotational direction that corrects the acquired θ correction amount, as shown in Figure 9. This corrects the rotational deviation at the moving point. The process then proceeds to step S7.

[0049] In step S7 shown in Figure 5, as shown in Figure 10, the control unit 4 is configured to perform control to acquire the θ-corrected coordinate C12, which is the coordinate of the one-sided mark M1 after the θ correction amount has been corrected, using the one-sided mark M1 whose one-sided coordinate C1 was acquired in step S3. That is, the imaging unit position P moves again so that the center of the field of view Ce of the imaging unit 2 is at the position of the ideal coordinate Ci1 corresponding to the one-sided mark M1 if there had been no displacement due to the movement of the stage 1, and the imaging unit 2 detects the one-sided mark M1 after the θ correction amount has been corrected. After that, the process proceeds to step S8.

[0050] In step S8 shown in Figure 5, as shown in Figure 11, the control unit 4 is configured to perform control to acquire the XY correction amount based on the θ-corrected coordinate C12 obtained by correcting the angular deviation of the θ correction amount of stage 1 for the acquired one coordinate C1, and the ideal coordinate Ci1 corresponding to one mark M1 when no deviation occurs due to the movement of stage 1. Specifically, the difference Δ between the θ-corrected coordinate C12 and the ideal coordinate Ci1 is the XY correction amount. After that, the process proceeds to step S9.

[0051] In step S9 shown in Figure 5, the control unit 4 determines whether the acquisition of the θ correction amount and XY correction amount at all moving points has been completed. If it is determined that the acquisition of the θ correction amount and XY correction amount at all moving points has been completed, the processing flow of the calibration method in stage 1 is terminated. If it is determined that the acquisition of the θ correction amount and XY correction amount at all moving points has not been completed, the process proceeds to step S10.

[0052] In step S10 shown in Figure 5, the control unit 4 is configured to rotate the stage 1, which was rotated in step S6, in the opposite direction by the amount of the θ correction. As a result, the state of the stage 1 returns to what it was before it was rotated by the amount of the θ correction in step S6. After that, the process returns to step S2.

[0053] (Effects of the first embodiment) In the first embodiment, the following effects can be obtained.

[0054] In the stage system 100 according to the first embodiment, as described above, the system is configured to perform the following actions at multiple moving points of the stage 1: control to acquire the coordinates of one mark M1 and the other mark M2, which are two of the multiple calibration marks M, for each movement; and control to acquire a θ correction amount to correct the deviation of the rotation angle on a plane parallel to the mounting surface 11, based on the acquired coordinates of one mark M1, which is one coordinate C1, and the other coordinate C2, which is the coordinate of the other mark M2, and the ideal coordinates when no deviation occurs due to the movement of the stage 1. Here, after the movement of the stage 1, by acquiring the coordinates of the two points of one mark M1 and the other mark M2, information on the line segment L connecting one mark M1 and the other mark M2 can be acquired. Furthermore, from the ideal coordinates Ci1 and Ci2, which are the ideal coordinates when no deviation occurs due to the movement of the stage 1, corresponding to the acquired one coordinate C1 and the other coordinate C2, information on the line segment Li, which is composed of the ideal coordinates Ci1 and Ci2 corresponding to the acquired one coordinate C1 and the other coordinate C2, can be acquired. This allows us to calculate the angle between the line segment L, which is formed by one mark M1 and the other mark M2, and the line segment Li, which is calculated using the ideal coordinates Ci1 corresponding to one mark M1 and Ci2 corresponding to the other mark M2, assuming there is no displacement due to the movement of the stage 1. This calculated angle can be obtained as a θ correction amount, which is the displacement of the rotation angle caused by the movement of the stage 1 in a plane parallel to the mounting surface 11 of the calibration substrate S. As a result, the displacement in the rotation direction caused by the movement of the stage 1 in a plane parallel to the direction of movement of the stage 1 can be corrected using the θ correction amount.

[0055] In the stage system 100 according to the first embodiment, as described above, the control unit 4 is configured to perform control to acquire the XY correction amount based on the acquired one coordinate C1 and the θ correction coordinate C12 obtained by correcting the angular deviation of the θ correction amount of the stage 1, and the ideal coordinate Ci1 corresponding to one mark M1 among the ideal coordinates Ci in the case where no deviation occurs due to the movement of the stage 1. As a result, the XY correction amount can be acquired with the rotation angle deviation corrected based on the θ correction amount, which is the rotation angle deviation caused by the movement of the stage 1. As a result, the XY correction amount can be acquired with the influence of the rotation direction deviation caused by the movement of the stage 1 reduced throughout the entire stage.

[0056] In the stage system 100 according to the first embodiment, the control unit 4 is configured to perform control to acquire a θ-corrected coordinate C12 that corrects the angular deviation of the θ-correction amount due to the rotation of the stage 1 around its rotation axis. This is achieved by rotating the stage 1 in the rotation direction that corrects the θ-correction amount, and then acquiring coordinates again from the one-sided mark M1 from which the one-sided coordinate C1 was acquired. As a result, by actually rotating the stage 1, the θ-corrected coordinate C12 that corrects the rotation angle deviation based on the θ-correction amount can be acquired. Furthermore, since the XY-correction amount for correcting the deviation in the direction parallel to the mounting surface 11 can be acquired simply by taking the difference Δ between the θ-corrected coordinate C12 that corrects the angular deviation of the θ-correction amount and the ideal coordinate Ci1 corresponding to the one-sided mark M1, the XY-correction amount can be acquired more easily while reducing the influence of the rotational deviation caused by the movement of the stage 1.

[0057] In the stage system 100 according to the first embodiment, the control unit 4 is configured to correct the movement amount of the imaging unit movement mechanism 3 using the calibration mark M before performing control to acquire the θ correction amount and the XY correction amount. Furthermore, the distance between the calibration mark M and the imaging unit 2 when correcting the movement amount of the imaging unit movement mechanism 3 is configured to be the same distance as the distance between the calibration mark M and the imaging unit 2 when acquiring the θ correction amount and the XY correction amount. As a result, the distance between the calibration mark M and the imaging unit 2 when correcting the movement amount of the third imaging unit movement mechanism is the same distance as the distance between the calibration mark M and the imaging unit 2 when acquiring the θ correction amount and the XY correction amount. Therefore, even if the optical axis of the imaging unit 2 is not perpendicular to the mounting surface 11 of the stage 1, there is no discrepancy between the coordinates of the calibration mark M acquired during the calibration of the imaging unit 2 and the coordinates of the calibration mark M acquired during the calibration of the stage 1 in the direction parallel to the mounting surface 11. As a result, the coordinates acquired during the calibration of the imaging unit 2 and the coordinates acquired during the calibration of the stage 1 can be made to match in the direction parallel to the mounting surface 11.

[0058] In the stage system 100 according to the first embodiment, in the control for acquiring the coordinates of two of a plurality of calibration marks M each time the stage 1 moves, the imaging unit 2 moves to detect one of the same two calibration marks M, one mark M1 and the other mark M2, at multiple movement points of the stage 1, and is configured to acquire one coordinate C1 of one of the same two calibration marks M1 and the other coordinate C2 of the other mark M2 at multiple movement points of the stage 1. As a result, with the imaging unit 2 moving to detect one of the same two calibration marks M, one mark M1 and the other mark M2, at multiple movement points of the stage 1, one coordinate C1 of one of the same two calibration marks M1 and the other coordinate C2 of the other mark M2 are acquired before and after the movement of the stage 1, so that the coordinates of the calibration marks M for each movement of the stage 1 can be acquired based on the movement of the imaging unit 2. As a result, the stage 1 can be calibrated at any interval, without depending on the interval between adjacent calibration marks M. Furthermore, in order to detect two identical calibration marks M, one mark M1 and the other mark M2, at multiple moving points in Stage 1, the imaging unit 2 will image both the two identical calibration marks M1 and the other mark M2. Because the imaging unit 2 images both the two identical calibration marks M1 and the other mark M2, it is possible to prevent calibration errors caused by errors in the shape of each calibration mark M and errors in the placement of the calibration marks M.

[0059] In the stage system 100 according to the first embodiment, one imaging unit 2 is provided, and at multiple moving points, the imaging unit 2 images one mark M1 to obtain one coordinate C1 of the one mark M1. Then, the imaging unit 2 moves to detect the other mark M2 and images the other mark M2 to obtain the other coordinate C2 of the other mark M2. As a result, the imaging unit 2 detects the other mark M2 and images it by moving, so the coordinate of the other mark M2 can be obtained without moving the stage 1. Consequently, since there is no rotational deviation caused by the rotation associated with the movement of the stage 1 in order to obtain the coordinate of the other mark M2, the θ correction amount of the stage 1 can be obtained more accurately.

[0060] [Second Embodiment] Next, a stage system 100a according to a second embodiment will be described with reference to Figures 12 and 13. The configuration of this stage system 100a according to a second embodiment is the same as that of the stage system 100 of the first embodiment shown in Figure 1, except that a first stage 1a and a second stage 1b are provided.

[0061] (Stage system configuration) As shown in Figure 12, in the second embodiment, the stage system 100a comprises two stages, a first stage 1a and a second stage 1b. The first stage 1a and the second stage 1b are arranged to overlap in a direction perpendicular to the first mounting surface 11a of the first stage 1a and the second mounting surface 11b of the second stage 1b when in use, and are configured such that the coordinates in the direction parallel to the first mounting surface 11a and the second mounting surface 11b coincide between the first stage 1a and the second stage 1b.

[0062] The stage system 100a in the second embodiment is used when it is necessary to match the coordinates of the first stage 1a and the second stage 1b in the direction parallel to the first mounting surface 11a and the second mounting surface 11b. For example, in a laser transfer apparatus, in order to transfer a chip on a substrate held by a donor table to an accurate position on a substrate held by a target table, it is necessary to match the coordinates of the first stage 1a, which moves the target table, and the second stage 1b, which moves the donor table, in the direction parallel to the first mounting surface 11a and the second mounting surface 11b.

[0063] However, the optical axis of the imaging unit 2 is aligned with the first mounting surface 11a and the second mounting surface 11b so that it is perpendicular to the first mounting surface 11a and the second mounting surface 11b. However, there may be a misalignment between the optical axis of the imaging unit 2 and the first mounting surface 11a and the second mounting surface 11b.

[0064] Stage 1a has the same configuration as Stage 1 shown in Figure 1.

[0065] The second stage 1b is configured to hold the substrate from above by the holding portion 16b. Therefore, in the second stage 1b, the calibration substrate S is placed on the substrate held by the holding portion 16b, which is used as the second mounting surface 11b.

[0066] Referring to Figure 13, we will explain the coordinate deviation that occurs when the optical axis of the imaging unit 2 is oblique to the first mounting surface 11a and the second mounting surface 11b, and when coordinates on the calibration substrate S are acquired while the distance between the calibration mark M and the imaging unit 2 is different during the calibration of each of the first stage 1a and the second stage 1b.

[0067] In Figure 13, the calibration substrate S21 is placed on the first mounting surface 11a, and the calibration substrate S22 is placed on the second mounting surface 11b. Furthermore, since the amount of movement of the imaging unit 2 is corrected by the calibration substrate S21 placed on the first mounting surface 11a, there is no discrepancy between the coordinates of the calibration mark M acquired during the calibration of the imaging unit 2 and the coordinates of the calibration mark M acquired during the calibration of the first stage 1a in the direction parallel to the first mounting surface 11a.

[0068] The control unit 4a acquires the coordinates of the calibration mark M based on the image I captured by the imaging unit 2 and the amount of movement of the imaging unit movement mechanism 3. Therefore, the coordinates of the calibration mark M on the optical axis of the imaging unit 2 are acquired assuming they have the same coordinates. Consequently, the control unit 4a acquires the coordinates of the calibration mark M3 on the calibration substrate S21 and the calibration mark M4 on the calibration substrate S22 as the same coordinate value C3 as the coordinates in the direction parallel to the first mounting surface 11a. However, since the coordinates of the calibration mark M4 on the actual calibration substrate S22 in the direction parallel to the first mounting surface 11a are coordinate value C4, a discrepancy occurs between the coordinates acquired during the calibration of the first stage 1a and the second stage 1b.

[0069] In order to match the coordinates acquired during the calibration of the first stage 1a and the second stage 1b, the system is configured to acquire the θ correction amount and XY correction amount for the first stage 1a and the second stage 1b while the distance between the calibration mark M and the imaging unit 2 is equal during the calibration of the first stage 1a and the second stage 1b.

[0070] (Effects of the second embodiment) In the second embodiment, the following effects can be obtained.

[0071] In the stage system 100a according to the second embodiment, a first stage 1a and a second stage 1b are provided. The first stage 1a and the second stage 1b are arranged to overlap in a direction perpendicular to the first mounting surface 11a and the second mounting surface 11b when in use, and the coordinates in a direction parallel to the first mounting surface 11a and the second mounting surface 11b are configured to coincide among the multiple stages. During the calibration of each of the first stage 1a and the second stage 1b, the θ correction amount and XY correction amount of the first stage 1a and the second stage 1b are acquired while the distance between the calibration mark M and the imaging unit 2 is equal. As a result, even when the optical axis of the imaging unit 2 is not perpendicular to the first mounting surface 11a and the second mounting surface 11b, when the first stage 1a and the second stage 1b are provided, the coordinates acquired during the calibration of the first mounting surface 11a and the second mounting surface 11b can be made to coincide in the direction parallel to the first mounting surface 11a and the second mounting surface 11b.

[0072] [Third Embodiment] Next, the stage system 100b according to the third embodiment will be described with reference to Figure 1 and Figures 14 to 19. The configuration of the stage system 100b according to this third embodiment is the same as that of the stage system 100 according to the first embodiment, except that the control by the control unit 4b is different, as shown in Figure 1.

[0073] The stage system 100b according to the third embodiment, like the stage system 100 according to the first embodiment, controls the acquisition of an XY correction amount that corrects the θ correction amount, which is the rotation angle deviation on a plane parallel to the mounting surface 11 of the stage 1. When the amount of movement of the stage 1 is corrected using the acquired θ correction amount, it becomes possible to correct the rotation component that occurs with the movement of the stage 1, so accurate calibration of the stage 1 can be performed. On the other hand, when the amount of movement of the stage 1 is corrected using the θ correction amount as in the first embodiment, the coordinates of the calibration mark M are acquired three times for each movement point, and the imaging unit 2 moves in order to acquire the θ correction amount for each movement point, so time is required for the calibration of the stage 1. Therefore, in addition to control to acquire an XY correction amount that corrects the θ correction amount, which is the rotation angle deviation, for accurate calibration, it is preferable to be able to perform control to easily acquire the correction amount of the stage 1 for daily calibration of the stage 1.

[0074] Therefore, the stage system 100b according to the third embodiment performs calibration based on the XY correction amount corrected by the θ correction amount, and then performs control to acquire the XY correction amount again. In other words, the stage system 100b according to the third embodiment acquires the XY correction amount corrected for the rotation component by the θ correction amount, similar to the first embodiment, and performs calibration of the stage 1 based on the XY correction amount. On the other hand, it differs from the first embodiment in that it acquires the XY correction amount again after the day on which calibration based on the XY correction amount was performed, and performs calibration based on the XY correction amount again. As a result, calibration based on the XY correction amount again makes it possible to correct the deviation caused by the movement of the stage 1 due to daily temperature changes, etc.

[0075] (Calibration method when recalibrating the stage) Referring to Figures 1 and 14-19, a simplified calibration method for Stage 1 in the Stage System 100b, which is a calibration method for re-correction, will be described in the third embodiment. Here, in Figures 15-17, the dashed lines arranged in a grid are provided for the convenience of explanation and represent the ideal coordinate Cib, which is the position of the calibration mark M when Stage 1 moves in the X-axis or Y-axis direction without any displacement due to the movement of Stage 1. Note that in Figure 15, the positions of the calibration substrate S and the ideal coordinate Cib overlap, so they are slightly offset for the convenience of drawing. In Figure 16, the ideal coordinate Cib represents the ideal position of the calibration mark M when Stage 1 is moved in the positive Y-axis direction by an indicated value equal to the distance W between the calibration marks M on Stage 1. Here, the indicated value for the movement of Stage 1 when acquiring the XY correction amount during re-correction is the same as the distance between the calibration marks M, unlike when acquiring the XY correction amount. For example, similar to the stage system 100 of the first embodiment, if the calibration mark M is a grid point of a grid pattern and the spacing W between grid points is 1 mm, the indicated value will be 1 mm in the X-axis direction or 1 mm in the Y-axis direction. Also, the re-correction movement point Mv(m,n) of the stage 1 shown in Figures 15, 16, 18, and 19 indicates the re-correction movement point Mv when the stage 1 moves m times from the origin O in the positive X-axis direction by the indicated value, and n times from the origin O in the positive Y-axis direction by the indicated value, as instructed by the control unit 4b. Specifically, the re-correction movement point Mv(0,0) in Figure 15 is the re-correction movement point Mv when the stage 1 moves 0 times from the origin O in the X-axis direction by the indicated value, and 0 times from the origin O in the Y-axis direction by the indicated value. In other words, it indicates a state where the stage 1 has not moved as instructed by the control unit 4b. Furthermore, the re-correction movement point Mv(0,1) in Figure 16 is the re-correction movement point Mv when the stage moves 0 times by the specified value in the X-axis direction from the origin O, and 1 time by the specified value in the positive Y-axis direction from the origin O. In other words, this is the state in which stage 1 has moved due to an instruction from the control unit 4b to move by W in the positive Y-axis direction.

[0076] First, in step S31 shown in Figure 14, as shown in Figures 1 and 15(a), the control unit 4b rotates the θ-axis stage 15 to adjust the position of the calibration mark M so that it aligns with the X and Y axes. Then, the process proceeds to step S32. In the following description, the position P of the imaging unit 2 on the calibration substrate S is positioned at the origin O. Figure 15(b) shows the captured image I when the imaging unit 2 captures the calibration mark M at the time the process of step S31 is completed. In Figure 15(b), the alignment of the calibration mark M with the origin O has been performed and the stage 1 has not yet moved, so there is no displacement due to the movement of the stage 1. Therefore, in the captured image I, the field of view center Ce (origin O) of the imaging unit 2 and the captured calibration mark M coincide.

[0077] Next, in step S32 shown in Figure 14, the control unit 4b (see Figure 1) moves stage 1 based on the instructed value for stage 1. Here, as shown in Figure 16(a), stage 1 is moved in the Y-axis direction based on an instructed value that is the same as the interval W between the calibration marks M. In other words, the control unit 4b controls stage 1 to move from the initial re-correction movement point Mv(0,0) to the re-correction movement point Mv(0,1). When acquiring the XY correction amount, the same calibration marks M are imaged by the imaging unit 2 before and after the movement of stage 1, and the amount of movement of stage 1 is acquired based on the amount of movement of the imaging unit 2, so the interval of the movement points does not depend on the interval W of the calibration marks M. On the other hand, the re-correction movement point Mv is determined based on the interval W between the calibration marks M. Therefore, the movement point when acquiring the XY correction amount may be different from the re-correction movement point Mv.

[0078] Next, in step S33 shown in Figure 14, as shown in Figures 1 and 16(a), the control unit 4b captures a calibration mark M using the imaging unit 2 and obtains the coordinates of the calibration mark M. The imaging of the calibration mark M may be performed by moving the imaging unit 2 by the same amount as the instruction value for stage 1, or it may be performed without moving the imaging unit position P of the imaging unit 2 from the origin O. Specifically, as in the first embodiment, the control unit 4b performs image processing on the captured image I to detect a calibration mark M in the captured image I that matches a previously registered image of the calibration mark M. The coordinates of the field of view center Ce of the imaging unit 2 can be calculated from the amount of movement of the imaging unit movement mechanism 3 (in Figure 16(b), the amount of movement when the imaging unit 2 is at the origin O). Therefore, based on the field of view center Ce of the imaging unit 2 and the detection position of the calibration mark M in the captured image I, the coordinates of the calibration mark M, which are the re-correction calibration mark coordinates, can be obtained. After that, the process proceeds to step S34.

[0079] Next, in step S34 shown in Figure 14, the control unit 4b (see Figure 1) acquires the XY correction amount for re-correction based on the instruction value for the movement of stage 1 and the calibration mark coordinates for re-correction. Here, as shown in Figure 16(b), the field of view center Ce of the imaging unit 2 is at the position of the calibration mark M when no displacement occurs due to the movement of stage 1, so the acquired calibration mark coordinates for re-correction become the XY correction amount for re-correction to correct the movement of stage 1. Specifically, the difference Δb between the calibration mark coordinates for re-correction shown in Figure 16(b) and the origin O becomes the XY correction amount for re-correction. Here, the ideal stage position after the movement of stage 1 when no displacement occurs due to the movement of stage 1 is (0, W), because it has moved by W in the positive Y-axis direction by the instruction value from the control unit 4b. On the other hand, the actual stage position after the movement of stage 1 is (Δbx, W + Δby), where the movement due to the instruction value is corrected by the difference Δb, and the x and y components of the difference Δb are Δbx and Δby, respectively. After that, the process proceeds to step S35.

[0080] Next, in step S35 shown in Figure 14, the control unit 4b (see Figure 1) determines whether the acquisition of the re-correction XY correction amount at all moving points has been completed. If it is determined that the acquisition of the re-correction XY correction amount at all moving points has been completed, the process proceeds to step S36. If it is determined that the acquisition of the re-correction XY correction amount has not been completed at all, the process proceeds to step S32. Note that the imaging unit 2 may be moved in step S34. Figure 17 shows the case where the process from step S32 to step S35 is repeated, and the stage 1 is moved multiple times in the positive X-axis direction and the positive Y-axis direction. At this time, if the imaging unit position P of the imaging unit 2 remains at the origin O, when the stage 1 is moved next in the positive X-axis direction or the positive Y-axis direction, the imaging unit 2 will not be able to capture the calibration mark M and will not be able to acquire the re-correction calibration mark coordinates. Therefore, by moving the imaging unit 2, the imaging unit 2 is made able to capture the calibration mark M even when the stage 1 is moved next in the positive X-axis direction or the positive Y-axis direction.

[0081] Next, in step S36 shown in Figure 14, the control unit 4b (see Figure 1) performs control to acquire a transformation matrix T for transforming multiple XY correction amounts acquired for each of the multiple re-correction movement points so that the re-correction amounts are minimized. The transformation matrix T is an example of the "transformation formula" in the claims. The XY correction amount map A1 and the transformation matrix T will be described below.

[0082] The recalibration XY correction amount map A1 shown in Figure 18 is a map in which the recalibration XY values ​​acquired for each recalibration movement point are placed on the corresponding recalibration movement point Mv. Specifically, the recalibration movement point Mv(m,n) of Stage 1 indicates the recalibration movement point Mv when Stage 1 moves m times from the origin O in the positive X-axis direction by the indicated value, and n times from the origin O in the positive Y-axis direction by the indicated value. The recalibration movement point Mv(-m,-n) of Stage 1 indicates the recalibration movement point Mv when Stage 1 moves m times from the origin O in the negative X-axis direction by the indicated value, and n times from the origin O in the negative Y-axis direction by the indicated value. Note that the indicated value is the distance that the control unit 4b instructs Stage 1 to move, so the ideal spacing between adjacent recalibration movement points Mv is equal to the spacing W between calibration marks M. Furthermore, the arrows indicated on the re-correction movement point Mv in the re-correction XY correction amount map A1 shown in Figure 18 represent the difference Δb, which is the re-correction XY correction amount obtained at movement point Mv.

[0083] Here, the control unit 4b (see Figure 1) calculates a transformation matrix T that minimizes the difference Δb, which is the XY correction amount obtained for each correction-time moving point Mv. Such a transformation matrix T can be expressed by the following equations (1) and (2), and the transformation matrix T can be obtained by finding the values ​​of a to h and s that minimize the value of the following equation (3).

number

number

number

[0084] Next, in step S37 shown in Figure 14, the control unit 4b (see Figure 1) performs control to acquire a corrected XY correction amount based on the XY correction amounts at multiple moving points and the transformation matrix T. That is, the corrected XY correction amount is obtained by multiplying the XY correction amounts for each of the multiple moving points acquired during the calibration in Stage 1 (see Figure 1) by the transformation matrix T acquired during the re-correction in Stage 1. After that, the calibration process during the re-correction in Stage 1 is terminated. (Effects of the third embodiment) In the third embodiment, the following effects can be obtained.

[0085] In the stage system 100b according to the third embodiment, as described above, when correcting the movement of the stage 1 again after calibration based on the XY correction amount, the control unit 4b is configured to perform the following controls: to acquire the calibration mark coordinates, which are the coordinates of the calibration mark M, for each of the multiple movement points Mv during the correction of the movement of the stage 1 again by moving the mounting surface 11 with the stage 1 in a direction parallel to the mounting surface 11 and imaging the calibration mark M with the imaging unit 2; to acquire the XY correction amount during the correction of the movement of the stage 1 again based on the calibration mark coordinates acquired for each of the multiple movement points and the instruction value, which is a value used to instruct the movement of the stage 1 used for each of the multiple movement points; to acquire the XY correction amount during the correction of the movement of the stage 1 again based on the calibration mark coordinates acquired for each of the multiple movement points and the instruction value, which is a value used to instruct the movement of the stage 1 used for each of the multiple movement points; to acquire a transformation matrix T for transforming so that the multiple XY correction amounts acquired for each of the multiple movement points are minimized; and to acquire a corrected XY correction amount based on the XY correction amount at each of the multiple movement points and the transformation matrix T. This allows the XY correction amount to be obtained during recalibration based on the coordinates of the recalibration calibration marks acquired for each of the multiple recalibration movement points, and the instruction values ​​used for instructing the movement of Stage 1 at each of the multiple recalibration movement points. Therefore, one imaging operation (acquisition of calibration mark coordinates) is performed by the imaging unit 2 to acquire one recalibration XY correction amount. In other words, the XY correction amount can be acquired in a shorter time than the XY correction amount. Furthermore, the transformation matrix T acquired based on the XY correction amount during recalibration can be used to convert the XY correction amount into a corrected XY correction amount, and the recalibration of the stage movement after calibration can be performed. As a result, the recalibration of the stage movement after calibration can be performed in a shorter time than by acquiring the recalibration XY correction amount and performing calibration.

[0086] [Differentiation] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and further includes all modifications (exceptions) within the meaning and scope equivalent to the claims.

[0087] In the first embodiment described above, the control unit 4 is configured to perform control to acquire the XY correction amount based on the acquired one coordinate C1 and the θ correction coordinate C12 obtained by correcting the angular deviation of the θ correction amount of the stage 1, and the ideal coordinate Ci1 corresponding to one mark M1 among the ideal coordinates Ci in the case where no deviation occurs due to the movement of the stage 1. However, the present invention is not limited to this. For example, the control unit 4 may be configured to perform control to acquire the XY correction amount based on the acquired one coordinate C1 and the ideal coordinate Ci1.

[0088] Furthermore, in the first embodiment described above, the control unit 4 is configured to perform control to acquire the XY correction amount based on the acquired one coordinate C1 and the θ correction coordinate C12 obtained by correcting the angular deviation of the θ correction amount of the stage 1, and the ideal coordinate Ci1 corresponding to one mark M1 among the ideal coordinates Ci in the case where no deviation occurs due to the movement of the stage 1. However, the present invention is not limited to this. For example, the control unit 4 may be configured to perform control to acquire the XY correction amount based on the θ correction coordinate C12 and the ideal coordinate Ci corresponding to a calibration mark M other than one mark M1. Even if the ideal coordinate Ci corresponds to a mark other than one mark M1, the XY correction amount can be acquired from the relative positional relationship.

[0089] Furthermore, in the first embodiment described above, an example was shown in which the coordinates of one mark M1 were acquired again after actually rotating the stage 1 by the θ correction amount to obtain the θ correction coordinate C12, but the present invention is not limited to this. For example, if the coordinates of the rotation axis of the stage 1 have been acquired in advance, the control unit 4 may be configured to perform a calculation to rotate one coordinate C1 around the rotation axis of the stage 1 by the θ correction amount, thereby obtaining the θ correction coordinate C12, which corrects the angular deviation of the θ correction amount due to the rotation around the rotation axis of the stage 1. This eliminates the need to actually rotate the stage 1, and thus reduces the number of steps in the calibration process.

[0090] Furthermore, in the first embodiment described above, an example was shown in which the distance between the calibration mark M and the imaging unit 2 when correcting the amount of movement of the imaging unit movement mechanism 3 is equal to the distance between the calibration mark M and the imaging unit 2 when acquiring the θ correction amount and the XY correction amount. However, the present invention is not limited to this. For example, if the optical axis of the imaging unit 2 is perpendicular to the mounting surface 11, the distance between the calibration mark M and the imaging unit 2 when correcting the amount of movement of the imaging unit movement mechanism 3 does not have to be equal to the distance between the calibration mark M and the imaging unit 2 when acquiring the θ correction amount and the XY correction amount.

[0091] Furthermore, in the first embodiment described above, the imaging unit position P is moved again so that the center of the imaging unit 2's field of view Ce is at the position of the ideal coordinate Ci1 corresponding to one mark M1, assuming there was no displacement due to the movement of the stage 1, and the imaging unit 2 obtains the XY correction amount by detecting one mark M1 after correcting the θ correction amount. However, the present invention is not limited to this. For example, the stage 1 may move after the imaging unit 2 detects one mark M1, so that the center of the imaging unit 2's field of view Ce at the position of the ideal coordinate Ci1 corresponding to one mark M1 coincides with the center of one mark M1. This allows the stage 1 to be calibrated for each of the multiple movement points of the stage 1, based on the coordinate of the center of the imaging unit 2's field of view Ce at the position of the ideal coordinate Ci1 corresponding to one mark M1. That is, not only can the θ correction amount and XY correction amount be obtained for each of the multiple movement points of the stage 1, but the stage 1 may also be moved to the next movement point after the correction of the movement amount of the stage 1 by the θ correction amount and XY correction amount has been completed for each of the multiple movement points.

[0092] Furthermore, while the first embodiment described above shows an example of obtaining the coordinates of two identical calibration marks M, one mark M1 and the other mark M2, at multiple moving points of the stage 1, the present invention is not limited to this. For example, it is sufficient to obtain coordinates from any two points of the calibration marks M for each movement. Therefore, if the movement range of the stage 1 and the movement range of the imaging unit 2 are different, and at least one of the two marks M1 and the other mark M2 moves outside the movement range of the imaging unit 2 due to the movement of the stage 1, the calibration marks M from which to obtain coordinates can be re-selected from among the calibration marks M that are within the movement range of the imaging unit 2.

[0093] Furthermore, in the first embodiment described above, an example was shown in which, at multiple moving points, one imaging unit 2 acquires the coordinates C1 of one mark M1 by imaging it, and then the imaging unit 2 moves to detect the other mark M2 and acquires the coordinates C2 of the other mark M2 by imaging it. However, the present invention is not limited to this. For example, the present invention may include two imaging units 2, with one imaging unit 2 configured to image the one mark M1 and the other imaging unit 2 configured to image the other mark M2.

[0094] Furthermore, although the first embodiment described above shows an example where the instruction value for moving Stage 1 is constant (the calibration interval is constant), the present invention is not limited to this. The instruction value for moving Stage 1 does not have to be constant. For example, the wobble of each axis of the X-axis stage 12 and Y-axis stage 13 may be measured in advance using an autocollimator that measures the angle of the object, and the calibration interval may be determined according to the magnitude of the wobble.

[0095] Furthermore, in the first embodiment described above, in step S10 of the calibration method for stage 1, the stage 1 that was rotated in step S6 was rotated in the opposite direction to return to its original position by the amount of the θ correction, but the present invention is not limited to this. For example, the process in step S10 may be omitted. Instead of the process in step S10, the θ correction amount may be subtracted from the θ correction amount obtained at the next moving point.

[0096] Furthermore, in the first embodiment described above, when acquiring the coordinates of the calibration mark M, an example was shown in which the coordinates of the calibration mark M are acquired by performing image processing on the captured image I and detecting the calibration mark M in the captured image I that matches the image of the calibration mark M that has been registered in advance. However, the present invention is not limited to this. For example, the imaging unit 2 may be moved by the imaging unit movement mechanism 3 so that the field of view center Ce of the imaging unit 2 coincides with the center of the calibration mark M whose coordinates are to be acquired, and the coordinates of the calibration mark M may be acquired based on a predetermined origin O and the amount of movement of the imaging unit 2 by the imaging unit movement mechanism 3.

[0097] Furthermore, in the second embodiment described above, an example was shown in which the θ correction amount and XY correction amount for the first stage 1a and the second stage 1b are acquired when the distance between the calibration mark M and the imaging unit 2 is equal during the calibration of each of the first stage 1a and the second stage 1b, but the present invention is not limited thereto. For example, if the optical axis of the imaging unit 2 is perpendicular to the first mounting surface 11a and the second mounting surface 11b, the θ correction amount and XY correction amount for the first stage 1a and the second stage 1b may be acquired when the distance between the calibration mark M and the imaging unit 2 is different during the calibration of each of the first stage 1a and the second stage 1b.

[0098] Furthermore, in the third embodiment described above, an example was shown in which a corrected XY correction amount is obtained by applying a transformation matrix T calculated based on the XY correction amount at the time of re-correction to the XY correction amount obtained during calibration, but the present invention is not limited thereto. For example, a trained model may be generated by performing machine learning using the XY correction amount and the XY correction amount at the time of re-correction as training data, and the generated trained model may be used to generate the XY correction amount based on the input of the XY correction amount at the time of re-correction.

[0099] Furthermore, although the third embodiment described above shows an example of obtaining a corrected XY correction amount based on one transformation matrix T and an XY correction amount, the present invention is not limited thereto. For example, the re-correction XY correction amount map A1 may be divided into multiple parts, and multiple transformation matrices may be calculated for each divided re-correction XY correction amount map A1 such that the sum of the absolute values ​​of the transformed re-XY correction amounts is minimized. In this case, the control unit 4b applies the transformation matrix to the XY correction amount corresponding to each of the multiple acquired transformation matrices to obtain a corrected XY correction amount.

[0100] Furthermore, although the third embodiment described above shows an example in which a homography transformation matrix is ​​calculated as the transformation matrix T, the present invention is not limited thereto. For example, the transformation matrix may be an affine transformation matrix.

[0101] Furthermore, in the third embodiment described above, the stage system 100b is shown to have one stage 1, similar to the configuration of the first embodiment, but the present invention is not limited thereto. It may have two stages, similar to the configuration of the second embodiment. [Explanation of symbols]

[0102] Stage 1 11 Mounting surface 1a Stage 1 11a First mounting surface 1b Stage 2 11b Second mounting surface 2 Imaging Unit 3. Imaging unit movement mechanism 4, 4a, 4b Control Unit 100, 100a, 100b Stage System Ce center of visual field Ci, Ci1, Ci2, Cib ideal coordinates I. Acquired images S Calibration Substrate M Calibration Mark M1 Meanwhile Mark M2 Other Mark A1 XY Correction Amount Map during Re-correction Movement point when Mv is corrected again T transformation matrix

Claims

1. A stage is configured such that a mounting surface on which a substrate is placed, or a calibration substrate placed on the aforementioned mounting surface, has multiple calibration marks arranged at predetermined intervals, and the aforementioned mounting surface is movable in a direction parallel to the aforementioned mounting surface and rotatable within a plane parallel to the aforementioned mounting surface. An imaging unit for capturing the calibration mark, An imaging unit moving mechanism that moves the imaging unit in a direction parallel to the mounting surface described above, The system includes a control unit that acquires the coordinates of the calibration mark based on the captured image of the calibration mark and the amount of movement of the imaging unit movement mechanism during the capture of the image, The control unit, during the calibration of the stage, Control to move the aforementioned stage in a direction parallel to the aforementioned mounting surface, Control to acquire the coordinates of two of the calibration marks at each of the multiple movement points of the stage, A control system that acquires a θ correction amount to correct the rotation angle deviation on a plane parallel to the aforementioned mounting surface, based on the coordinates of the two calibration marks acquired and the ideal coordinates when no deviation occurs due to the movement of the stage. A stage system configured to perform control to acquire an XY correction amount to correct for a misalignment in a direction parallel to the mounting surface.

2. The stage system according to claim 1, wherein the control unit is configured to perform control to acquire the XY correction amount based on a θ correction coordinate obtained by correcting the angular deviation of the θ correction amount of the stage for one of the coordinates of the two acquired calibration marks, and an ideal coordinate in the case where no deviation occurs due to the movement of the stage.

3. The control unit, After rotating the stage in the rotational direction that corrects the θ correction amount, control is performed to acquire coordinates again from the calibration mark from which the one coordinate was acquired, thereby acquiring the θ correction coordinates that have been corrected for the angular deviation of the θ correction amount due to the rotation around the rotation axis of the stage. Alternatively, if the coordinates of the rotation axis of the stage have been acquired in advance, the stage system according to claim 2 is configured to perform control to acquire the θ-corrected coordinates, which are obtained by performing a calculation to rotate the one coordinate around the rotation axis of the stage by the amount of the θ correction, thereby correcting the angular deviation of the θ correction amount due to the rotation around the rotation axis of the stage.

4. The control unit is configured to correct the amount of movement of the imaging unit movement mechanism using the calibration marks before performing the control to acquire the θ correction amount and the XY correction amount. The stage system according to claim 1, wherein the distance between the calibration mark and the imaging unit when correcting the amount of movement of the imaging unit movement mechanism is equal to the distance between the calibration mark and the imaging unit when acquiring the θ correction amount and the XY correction amount.

5. Multiple stages are provided, The multiple stages are arranged so as to overlap in a direction perpendicular to the surface of the aforementioned mounting surface when in use, and are configured such that the coordinates of the multiple stages in a direction parallel to the surface of the aforementioned mounting surface coincide. The stage system according to claim 4, configured to acquire the θ correction amount and the XY correction amount for each of the multiple stages while the distance between the calibration mark and the imaging unit is equal during the calibration of each of the stages.

6. The stage system according to claim 1, wherein, in the control for acquiring the coordinates of two of the plurality of calibration marks each time the stage moves, the imaging unit is configured to move so as to detect the same two calibration marks at multiple moving points of the stage, and to acquire the coordinates of the same two calibration marks at multiple moving points of the stage.

7. The imaging unit is provided as one unit. The stage system according to claim 1, wherein at the plurality of moving points, the imaging unit is configured to acquire the coordinates of one of the two calibration marks by imaging one of the calibration marks, and then the imaging unit moves to detect the other of the two calibration marks and acquire the coordinates of the other mark by imaging it.

8. The control unit, When correcting the movement of the stage again after performing the calibration based on the XY correction amount, the control is performed to move the aforementioned mounting surface in a direction parallel to the aforementioned mounting surface by the stage and capture the calibration mark with the imaging unit, thereby acquiring the coordinates of the calibration mark, which are the coordinates of the calibration mark, for each of the multiple movement points during the correction of the movement of the stage again. Control to acquire the XY correction amount during recorrection based on the recorrection calibration mark coordinates acquired for each of the multiple recorrection movement points and the instruction value which is a value used for instructing the movement of the stage used for each of the multiple recorrection movement points, Control to obtain a conversion formula for converting multiple XY correction amounts obtained for each of the multiple re-correction movement points so as to minimize them, The stage system according to claim 1, configured to perform control to acquire a modified XY correction amount based on the XY correction amount at the plurality of moving points and the conversion formula.

9. A calibration method for a stage on which a mounting surface on which a substrate is placed or a calibration substrate placed on the aforementioned mounting surface is arranged at predetermined intervals, and the aforementioned mounting surface is configured to be movable, The steps include moving a stage that is configured to be movable in a direction parallel to the mounting surface, The steps include obtaining the coordinates of two of the multiple calibration marks at each of the multiple movement points of the aforementioned stage, A step of obtaining a θ correction amount to correct the rotation angle deviation on a plane parallel to the aforementioned mounting surface, based on the coordinates of the two calibration marks obtained and the ideal coordinates when no deviation occurs due to the movement of the stage, A method for calibrating a stage, comprising the step of obtaining an XY correction amount to correct a deviation in a direction parallel to the mounting surface.

Images