KR20070033878A - Position measuring method and position measuring device and position measuring system - Google Patents

Abstract

assignment

When measuring the position of the measurement target point on the board | substrate 12, the error of the movement amount error of the cameras A-C and the visual field position of the cameras A-C by the posture change of the cameras A-C is a position measurement Do not fall short of the results.

Resolution

The measurement target point on the board | substrate 12 is imaged with cameras A-C, and only the table 5 is moved to ay direction, without moving the camera A-C as it was when the said image was picked up, and the board | substrate 12 Image of the reference scale 13 of the image is imaged with the cameras A to C, the amount of movement of the table 5 in the movement is measured by a linear encoder, the image of the measurement target point and the image of the reference scale 13 and The position of a measurement target point is calculated | required using the movement amount of the table 5.

Position measuring method, position measuring device, position measuring system

Description

Position measuring method and position measuring device and position measuring system {Position Measuring Method, Position Measuring Apparatus and Position Measuring System}

BRIEF DESCRIPTION OF THE DRAWINGS The perspective view which shows schematic structure of the position measuring system which concerns on one Embodiment of this invention.

2 is a plan view of the position measuring device of FIG.

3 is an enlarged view of a reference scale.

4 is a diagram showing a procedure of a position measuring method.

FIG. 5 is a diagram showing a measurement procedure of coordinates of a point P using a camera A. FIG.

FIG. 6 is a plan view of the position measuring device showing state a in FIG. 5; FIG.

FIG. 7 is a plan view of the position measuring device showing state b in FIG. 5; FIG.

8 is a diagram schematically showing a captured image for explaining the calculation of the coordinates of the point P by image processing and calculation.

9 is a diagram for explaining a search procedure of imaging of a measurement target point.

10 is a diagram illustrating a measurement procedure of coordinates of points P, Q, R, and S using the camera A. FIG.

FIG. 11 is a plan view of the position measuring device showing state c in FIG. 10. FIG.

12 is a plan view of the position measuring device showing the state b 'in FIG.

FIG. 13 is a plan view of the position measuring device showing state d in FIG. 10; FIG.

14 is a plan view of the position measuring device showing the state e in FIG.

FIG. 15 is a plan view of the position measuring device showing the state f in FIG. 10; FIG.

16 is a plan view of the position measuring device showing the state e 'in FIG.

FIG. 17 is a diagram illustrating a measurement procedure of coordinates of points Q and S using cameras A and B. FIG.

18 is a plan view of the position measuring device showing state g in FIG. 17.

19 is a plan view of the position measuring device showing the state h in FIG. 17;

20 is a diagram showing a measurement procedure of coordinates of a point T using cameras A to C. FIG.

21 is a plan view of the position measuring device showing the state i in FIG. 20;

22 is a plan view of the position measuring device showing the state j in FIG. 20.

Fig. 23 is a plan view of the position measuring device showing state k in Fig. 20.

24 is a plan view corresponding to FIG. 2 of another embodiment of the present invention;

(Explanation of symbols for the main parts of the drawing)

1: position measuring device

2: control device

5: table

6: trestle

12: substrate

13: reference scale

Technical field

This invention relates to the method and apparatus for measuring the position of the measurement object location on a board | substrate with respect to board | substrates, such as a glass substrate for liquid crystal panels, and a position measuring system using the same.

Background technology

In order to check the manufacturing dimensional accuracy of the substrate, a measurement object such as a substrate is placed on a base or a moving table, and the measurement object is imaged by a camera that is relatively movable with respect to the measurement object. Processing of an image and obtaining the position of a measurement target point are performed. For example, Patent Document 1 describes mounting a measurement object on a fixed stage and imaging the measurement object with a camera mounted on a stage moving in one direction.

Patent Document 1: Japanese Patent Laid-Open No. 2003-28611

Regarding the amount of movement of the table on the base, it is relatively easy to measure or control precisely, while the field of view of the camera that picks up an object to be measured on the table from above is relatively accompanied with the movement of the camera. Big error occurs. This error in the viewing position may be due to an error in the amount of movement of the camera itself or a change in the attitude of the camera. The error in the visual field position due to the change in the attitude of the camera is caused by the change in the optical axis direction of the camera with the change in the attitude of the camera, and as a result, the position of the visual field on the measurement object changes.

It is difficult to make the error of the visual field position of a camera small enough by mechanical precision. In particular, since the error caused by the change in the attitude of the camera is sensitive to the slight inclination of the camera, it is very difficult to make the error sufficiently small. For example, assuming that the distance between the camera and the measurement object is 200 mm, the inclination of the camera is only 1/1000 degrees, and the positional variation of the field of view on the measurement object is 3.5 µm in size. This change in camera posture is difficult to avoid every time the camera is moved, but this error is unacceptable when a high-precision measurement such as when inspecting the glass substrate of the liquid crystal panel is required.

An object of the present invention is to ensure that the error in the amount of movement of the camera and the error in the field of view of the camera due to the change in attitude of the camera do not fall short of the position measurement result when measuring the position of the measurement target point on the substrate.

Means to solve the problem

(1) The position measuring method of the present invention includes a base, a table moving in the first direction on the base, a movement amount measuring unit for measuring the amount of movement of the table, and a mount fixed to the base. Iii), a camera moving mechanism provided on the mount and having a second direction orthogonal to the first direction, and a camera supported by the camera moving mechanism and moving in a second direction from above the base. And a position measuring device having a reference scale provided on the table along a direction perpendicular to the moving direction of the table and giving a reference scale in the picked-up image when the image is taken by the camera.

The board | substrate made into a measurement object is mounted to the said table, image of one of the measurement object location and a reference scale on the said board | substrate is moved, and the said camera movement mechanism moves only the said table without moving as it was when the said imaging was performed. Image of the measurement target point on the substrate and the other of the reference scale with the camera, and measure the movement amount of the table in the movement by the movement amount measuring device, and the image and table of the obtained measurement target point and the reference scale. Using the movement amount of, the position of the measurement target point is obtained.

The movement amount measuring device is not limited to measuring the movement amount of the table directly, for example, like a linear encoder, but may indirectly measure the movement amount of the table to obtain the movement amount from the command value of the movement amount of the table.

The mount is hypothesized so that the camera supported by the camera moving mechanism provided in the mount crosses the moving area of the table on the base so that the camera and the reference scale mounted on the table can be imaged from above. It is preferable.

Since the camera is supported by the camera moving mechanism having the second direction as the movable direction and moves in the second direction, the camera can move the camera in the second direction by moving the camera moving mechanism, while moving the camera. When the instrument is not moving, the camera does not move and remains as it is.

Since the reference scale is provided on the table, the positional information of the field of view of the camera given in the image of the camera at the time of imaging this reference scale becomes the information based on the position of the table. Since the reference scale is provided along a direction perpendicular to the movement direction of the table, that is, along the second direction, which is the movement direction of the camera, the reference scale is taken at each movement position in the movement direction of the camera. Information of the position of the visual field can be obtained by this. It is preferable that this reference scale gives information of the position of the visual field regarding the said 1st direction and the said 2nd direction. The reference scale preferably has a pattern giving information in the first direction and the second direction, and the pattern may be added with information giving coordinate values in both directions of the pattern.

In the position measuring method of the present invention, three kinds of information are used. The first information used is an image of a reference scale. From this image, the position of the field of view of the camera at the time of reference scale imaging can be obtained. The position of this visual field is a position with respect to the position of the reference scale at the time of reference scale imaging, ie, the position of the table at that time. An error occurs in the position of the field of view due to an error in the amount of movement of the camera and a change in the attitude of the camera. However, even if there is an error in the position of the field of view, the position of the field of view by using the position of the field of view obtained from the image of the reference scale image taken. The error of does not affect the position measurement result.

The second information to be used is the movement amount of the table between the reference scale image pickup and the measurement target point image pickup. By using the first information and the second information, the position of the visual field at the time of imaging the measurement target point based on the position of the table at the time of reference scale imaging can be obtained.

The third information used is an image of a measurement target point. By this image, the position of a measurement target location based on the field of view of the camera at the time of imaging the measurement target location can be obtained. Therefore, by using all the information, the position of the measurement target point based on the position of the table at the time of reference scale imaging can be obtained. If the relative positional relationship between the table and the base is found when measuring the amount of movement of the table, the position of the measurement target point based on the expectation can be obtained by the position measuring method of the present invention.

According to the position measuring method of this invention, when measuring the position of the measurement target point on a board | substrate, by the imaging of a reference scale, the influence of the error of the visual field position of the camera which arises by the movement amount error of a camera and the attitude | position fluctuation of a camera is located. It is possible not to fall short of the measurement results. In addition, while the camera is photographing either the measurement target point on the substrate and the reference scale, and the camera captures the measurement target point on the substrate and the other side of the reference scale with the camera, the camera is moved with respect to the expectation without moving the camera. Since it is stationary, it can prevent that the error of the visual field position of a camera arises during this time. Thereby, the measurement precision of the position of a measurement object location improves.

(2) In one embodiment of the position measuring method of this invention, the said position measuring apparatus is prepared, the board | substrate made into a measurement object is mounted to the said table | surface, the image of the measurement object location on the said board | substrate is imaged with the said camera, and An image of the measurement target point obtained by moving only the table without moving the camera movement mechanism as it was when the image was taken and imaging a reference scale with the camera, measuring the movement amount of the table in the movement by the movement amount measuring device. And the position of the measurement target point by using the image of the reference scale and the movement amount of the table.

In the position measuring method of the present embodiment, the reference scale is imaged after imaging the measurement target point. By the way, it is also conceivable to image the measurement target point after imaging the reference scale in reverse order. In that case, the mounting position of the substrate is shifted so as to rotate within the plane, or the precision of the formation position of the imaging target. Due to the poor or the like, the object to be measured may not be found in contrast to the assumption in the field of view after the table movement, and the assumed position at which the object to be measured is found must be changed. When the position of the camera moves along with this, there is a possibility that an error may occur due to the movement of the camera. Therefore, in the method in which the reference scale has been imaged first, it is necessary to start again from the image pickup of the reference scale.

On the other hand, in the position measuring method of this embodiment which image | photographs a measurement object point, and image-captures a reference scale, when a measurement object point is not found in the visual field which put the assumed position of a measurement object point, either of a table and a camera Or it is only necessary to move the both sides little by little to search for the measurement target point and to capture the reference scale by moving only the table without moving the camera at a position where the measurement target point can be picked up.

(3) In embodiment of said (2), the said position measuring apparatus is prepared, the board | substrate made into a measurement object is mounted on the said table, the 1st measurement object location on the said board | substrate is imaged with the said camera, and the said camera A first movement is made to the table without moving the moving mechanism to capture a reference scale with the camera to obtain a first image of the reference scale, and the first movement amount of the table in the first movement is measured by the movement amount measuring instrument. Is measured by the camera, and the camera surface is photographed with a substrate surface point at which the second measurement target point exists by causing a second movement to the table without moving the camera moving mechanism.

If the second measurement target point is included in the image picked up, the image is adopted as the image of the second measurement target point, and if the second measurement target point is not included in the picked-up image, The imaging is repeated by microscopically moving the table or camera moving mechanism until the imaging is successful,

When the second movement amount of the table is measured by the movement amount measuring device, or when the table is subjected to the fine movement, the movement amount measuring device is used as the second movement amount as a cumulative movement amount that adds the fine movement portion to the second movement amount. Measure it,

When the camera movement mechanism is moved until the imaging of the second measurement target point is successful, the third movement is made to the table without moving the camera movement mechanism in the state when the imaging of the second measurement target point is successful. Image of the reference scale to obtain a second image of the reference scale, the third movement amount of the table is measured by the movement amount measuring instrument,

The obtained images of the first and second measurement target points, the first image of the reference scale and the first and second movement amounts of the table, and the second image of the reference scale and the third movement amount of the table, if present The positions of the first and second measurement target points may be determined.

According to this embodiment, the position of two measurement object points separated in the moving direction of a table can be measured by small table movement.

(4) In the embodiment of (2), the first camera moving mechanism and the second camera moving mechanism that can move independently of each other, the first camera supported by the first camera moving mechanism, and the second The said camera is equipped with the 2nd camera supported by the camera movement mechanism, the said position measuring apparatus which has the visual field of the 1st and 2nd camera separated from each other in the direction perpendicular | vertical to the movement direction of a table is prepared, and it is a measurement object to the said table The board | substrate made into the board | substrate is image | photographed, the 1st camera object image on the said board | substrate is imaged by a 1st camera, and a 2nd camera object image is captured by a 2nd camera, and a 1st and 2nd camera movement mechanism is not moved. The table is moved, and the reference scale is imaged by the first and second cameras, respectively, and the movement amount of the table in the movement is measured by the movement amount measuring device. To obtain the positions of the first and second measurement target points using the images of the second measurement target points, the first and second images of the reference scales respectively photographed with the first and second cameras, and the movement amounts of the tables. You may also do it.

The first and second cameras are mounted on the mounts which cross in the direction perpendicular to the movement direction of the table so as to traverse the movement area of the table so as to secure a separate view in the direction perpendicular to the movement direction of the table. It is preferred that the first and second camera moving mechanisms are respectively supported.

It is preferable that imaging of the 1st and 2nd measurement object points by a 1st and 2nd camera, and imaging of the reference scale by a 1st and 2nd camera are performed simultaneously with a 1st and a 2nd camera, respectively. Do.

According to the present embodiment, two cameras can be used to measure the positions of two measurement target points spaced apart in a direction perpendicular to the moving direction of the table by using small table movement.

(5) In the above embodiment (2), the first camera moving mechanism and the second camera moving mechanism that can move independently of each other, the first camera supported by the first camera moving mechanism, and the second The said camera is equipped with the 2nd camera supported by the camera movement mechanism, the said position measuring apparatus which has the visual field of the 1st and 2nd camera separated from each other in the direction perpendicular | vertical to the movement direction of a table is prepared, and it is a measurement object to the said table The board | substrate which sets it as the board | substrate, image | photographs the 1st measurement object location on the said board | substrate with a 1st camera, and does not move as it was when the 1st camera moving mechanism was imaged, does the 1st movement to the said table. 2nd camera object image is imaged with a 2nd camera, the 1st movement amount of the table in a 1st movement is measured by the said movement quantity measuring device, and 1st and 2nd A second movement is made to the table without moving the camera moving mechanism, and the reference scale is imaged by the first and second cameras, respectively, and the second movement amount of the table in the second movement is measured by the movement amount measuring device. The first and second images of the reference scale imaged by the first and second measurement target points, the first and second cameras respectively, and the first and second movement amounts of the table, respectively, are obtained. The positions of the first and second measurement target points may be determined.

When moving the second camera moving mechanism may change the viewing position of the first camera, between the imaging of the first measurement target point and the imaging of the second measurement target point, the first It is preferable that not only the camera moving mechanism but also the second camera moving mechanism not move. Therefore, when it is necessary to move a 2nd camera moving mechanism in order to image a 2nd measurement object point with a 2nd camera, before imaging a 1st measurement object point with a 1st camera, it is 2nd in advance. It is preferable to keep the camera moving mechanism of the camera.

According to this embodiment, two cameras can be used to measure the position of two measurement object points of arbitrary positions on a board | substrate by small table movement.

In this embodiment, a 1st camera, a 2nd camera, or another camera is made between the imaging (1st imaging) of the 1st measurement object point, and the imaging (2nd imaging) of the 2nd measurement object point. You may image | photograph another measurement object point using this. In that case, the cumulative movement amount (distance from the table position at the time of the first imaging to the table position at the time of the second imaging) of the table from the first imaging to the second imaging is determined as the first of the table. Is the amount of movement.

In this embodiment, using the position measuring apparatus which supported more cameras, such as a 3rd camera and a 4th camera, to each camera movement mechanism, the table is moved to the measurement object location corresponding to the number of cameras sequentially. The imaging may be performed by using a camera, and imaging of the reference scale by each camera may be performed at a common table position. In this case, when two or more of the measurement target points are spaced apart in the moving direction of the table, the measurement target points can be captured by a common camera. The position can be measured.

In addition, when two or more of the measurement target points are separated in the direction perpendicular to the moving direction of the table, these measurement target points can be picked up at a common table position. Needless to say, there is no limitation on the number of measurement target points that can be measured regardless of the number of cameras as long as the camera moving mechanism is moved. However, between the movement of the camera movement mechanism and the next movement of the camera movement mechanism, imaging of the reference scale must be performed once with a camera supported by the camera movement mechanism.

(6) The position measuring method according to any one of (1) to (5), wherein a pattern that can be picked up is provided on the substrate, and a measurement target point on the substrate is at least two reference marks selected from the pattern, The position and attitude of the said pattern may also be calculated | required using the obtained position of the at least 2 reference mark.

(7) The position measuring method according to any one of (1) to (5), wherein an image pickup pattern is provided on the substrate, and a measurement target point on the substrate is a first point and a second point selected from the pattern. It is a point, and the position of the obtained 1st point and 2nd point may be used, and also the distance between a 1st point and a 2nd point may be calculated | required.

(8) The position measuring method according to any one of the above (1) to (5), wherein an image pickup pattern is provided on the substrate, and the measurement target points on the substrate are selected from the first, second, and third patterns. And a fourth point, a straight line connecting the first point and the second point using the positions of the obtained first, second, third, and fourth points, and the third point and the fourth point. The angle formed by the straight line connecting each other may be obtained.

The second point and the third point may be one common point.

According to this embodiment, the information regarding the deformation | transformation of a pattern can be obtained. In particular, when selecting a point to be measured so that two straight lines are orthogonal, the orthogonality is measured to obtain deformation information with high sensitivity.

(9) The position measuring device of the present invention includes a base, a table moving in a first direction from the base, a movement amount measuring unit for measuring the amount of movement of the table, a mount fixed to the base, and the mount A camera moving mechanism provided with a second direction orthogonal to the first direction, as a movable direction, a camera supported by the camera moving mechanism and moving in a second direction from above the base, and a moving direction of the table It is provided on the table along the direction perpendicular | vertical to and has the reference scale which gives the information regarding the position of the visual field of a camera in a picked-up image when it is picked up by the said camera.

According to the position measuring device of the present invention, it is possible to prevent the influence of the error in the movement amount of the camera and the error in the field of view of the camera caused by the change in the attitude of the camera caused by the imaging of the reference scale so as not to fall short of the position measurement result.

In addition, since the camera is stopped with respect to the base during the imaging of the measurement target point and the reference scale on the substrate, it is possible to prevent an error in the viewing position of the camera during this time. Thereby, the measurement precision of the position of a measurement object location improves.

(10) In one embodiment of the position measuring apparatus of this invention, the said reference scale is provided in the both sides of the movement direction of a table, sandwiching the area | region where the board | substrate on the table should be mounted.

According to the present embodiment, any reference scale can be used as long as the positional relationship between the reference scales on both sides is known, so that the movement amount of the table can be reduced by appropriately selecting the reference scale to be used.

(11) The position measuring system of the present invention includes the position measuring device (9) or (10) and a control device connected to the position measuring device and capable of transmitting information to each other, wherein the control device controls A computer for executing a program, wherein the control program captures any one of a measurement target point on a substrate placed on a table of the position measuring device and a reference scale with the camera, and captures the camera movement mechanism. Move only the table without moving as it is, and pick up the measurement target point on the substrate and the other side of the reference scale with the camera, measure the movement amount of the table in the movement by the movement amount measuring device, and obtain the measurement target point. The position of the measurement target point is calculated by using the image of the image, the image of the reference scale, and the amount of movement of the table. It is provided with a tab.

According to the position measuring system of this invention, when measuring the position of the measurement target point on a board | substrate, the influence of the error of the camera's visual field position which arises by the camera movement amount error and the attitude | position fluctuation of a camera by imaging of a reference scale is a position measurement. It is possible not to fall short of the results. In addition, since the camera is stationary with respect to the base during the imaging of the measurement target point and the reference scale on the substrate, it is possible to prevent an error in the viewing position of the camera at this time. This improves the position measurement accuracy at the measurement target point.

To practice the invention  Best form for

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail based on drawing.

1 is a perspective view showing a schematic configuration of a position measuring system according to an embodiment of the present invention, and FIG. 2 is a plan view of the position measuring device.

As shown in FIG. 1, the position measuring system of this embodiment is equipped with the position measuring apparatus 1 and the control apparatus 2 connected to this position measuring apparatus 1 so that mutual information transmission is possible, The control device 2 has a built-in computer that executes a control program for controlling the position measuring device 1.

The position measuring device 1 includes a base 5 made of stone such as granite, a table 5 movable along a pair of guide rails 4 provided thereon, and the table 5. The door-shaped mount frame 6 arranged at a fixed position on the base 3 in the form of crossing the frame, a plurality of camera movement mechanisms (not shown) provided in the mount frame 6, and each camera movement mechanism. A plurality of supported cameras (three in this embodiment) are provided.

The rectangular plate-shaped table 5 is movable in the y direction (left-right direction of FIG. 2) of the figure which is 1st direction by drive mechanisms, such as a linear motor which is not shown in figure. Each of the cameras A to C is independent of each other in the x direction by each camera moving mechanism whose x direction (up and down direction in FIG. 2) in the drawing, which is the second direction orthogonal to the first direction, is the moving direction. It is movable.

The linear scale 10 which extends along the y direction which is the moving direction of the table 5 is provided on the base 3, The lower surface of the table 5 is not shown to move integrally with the said table 5, The encoder head is provided, and the linear scale 10 and the encoder head constitute a linear encoder as a movement amount measuring device for measuring the movement amount in the y direction of the table 5.

Two linear scales 10 and two encoder heads are provided, and two linear encoders are comprised, and each linear encoder measures the amount of movement of the front side and the crossing side in FIG. 1 of the table 5, respectively.

Each encoder head is provided with a light-transmitting part and a light-receiving part, and receives the reflected light emitted from the light-transmitting part and modulated by the linear scale 10 at the light-receiving part, so that the amount of movement of the table 5 is increased. A number of pulse signals can be obtained. Moreover, since the origin pattern is provided in one place of each linear scale 10, the origin signal of a table position can also be obtained. The two linear scales 10 are provided in order to correct the error of the amount of table movement caused by yawing (rotation in the horizontal plane) of the posture of the table 5.

Instead of the linear encoder, a laser interferometer or any other known movement amount measuring instrument can be used.

On the base 3, a laser displacement meter 11 is provided so as to face the side surface of the table 5, and the laser displacement meter 11 performs displacement measurement using the side surface of the table 5 as an object.

The laser displacement meter 11 includes a light transmission optical system for irradiating a laser beam to an object, and a light receiving optical system for receiving reflected light from the object by a position detecting element through a light receiving lens. The light-receiving optical axis intersects at a predetermined crossing angle in the vicinity of the object, and the position of the beam spot image formed by the formation of the spot of the laser beam on the object on the position detecting element is increased to the object. By using the displacement when the distance is changed, the distance to the object or the amount of change of the distance is determined by the principle of triangulation. The displacement measurement result by this laser displacement meter 11 is a value which shows the displacement amount of the table 5 with the movement of the table 5 in the x direction, and the board | substrate 12 as a measurement object mounted on the table 5 was carried out. It is used for the correction of the position measurement result about the measurement target point of the phase. Although the laser displacement meter 11 is shown in FIG. 1, 2, illustration of the laser displacement meter 11 is abbreviate | omitted in the following figure.

The table 5 on which the substrate 12 to be measured is placed is made of granite or the like like the base 3, and the table 5 includes positioning pins for contacting and positioning the substrate 12. A suction hole for sucking air from below the substrate 12 and bringing the substrate 12 into close contact with the table 5 is provided.

Further, near one end (left end of the drawing) on the table 5, a reference scale 13 extending in the x direction perpendicular to the moving direction (y direction) of the table 5 is provided, and this reference scale 13 Indicates information about the position of the visual field of each camera A to C in the captured image when the cameras A to C are imaged.

The substrate 12 is, for example, a glass substrate for a liquid crystal panel, and has a size of 730 mm in the x direction and 920 mm in the y direction. On the board | substrate 12, the reference mark and the wiring pattern which are not shown are formed by the etching of a metal film. The cross marks P, Q, R, S in Fig. 2 are reference marks. The position measurement with the precision of +/- 0.5 micrometer is calculated | required over the whole board | substrate 12.

Each camera moving mechanism incorporated in the mount 6 moves each camera A to C for imaging the substrate 12 mounted on the table 5 in the x direction. This camera movement mechanism is provided with the linear encoder, and each camera (A-C) by the x coordinate commanded from the control apparatus 2 is measured by the linear encoder, measuring the movement amount of each camera A-C in the x direction. Move). Since the error of the camera movement amount is corrected by the imaging of the reference scale 13, this linear encoder has no problem even if the resolution is rough, for example, about 1 m.

Each camera A-C has the structure which has an objective lens like a microscope, and is equipped with the two-dimensional CCD imaging element. The imaging magnification can be changed by replacing the objective lens. The magnitude | size of the visual field on the board | substrate 12 at the highest magnification is 144 micrometers in the x direction of FIG. 2, and 110 micrometers in a y direction.

The control apparatus 2 is equipped with a keyboard and a display, sends a command to the position measuring apparatus 1 in real time, observes the image imaged by the position measuring apparatus 1, or the position measuring apparatus 1 You can enter or control the program that controls). The program controlling the position measuring device 1 can also be downloaded from the outside via a network.

3 is an enlarged view of a part of the reference scale 13 of FIG. 2, and the x direction (up and down direction) of FIG. 2 corresponds to the up and down direction of FIG. 3, and the y direction (left and right direction) of FIG. 2. This corresponds to the left-right direction of FIG.

This reference scale 13 is made of glass such as soda glass, and in this embodiment, a repeating pattern of 100 µm cycle is formed in the x direction (up and down direction). This repeating pattern is a pattern arranged in the center of the long rectangular pattern so that the cross pattern is connected to the upper and lower sides without being connected to the left and right sides of the rectangular pattern.

This rectangular pattern has a length in the x direction (up and down direction) of 100 µm, a length in the y direction (left and right direction) of 200 µm, a length in the y direction (left and right direction) of the center cross pattern is 100 µm, The line width of each line constituting the pattern is 10 占 퐉.

The positional variation of the visual field of the cameras A to C caused by the movement amount error of the cameras A to C and the posture variation of the cameras A to C is made to be sufficiently smaller than 100 μm by mechanical precision. Therefore, by using the command value or the measured value of the camera position in the x direction, it is determined which cycle pattern of the reference scale 13 is being viewed. When the reference scale 13 is imaged, the pattern of the reference scale 13 in the field of view is taken. The x coordinate in the coordinate system based on the table 5 of the point of the image (for example, the center of the cross pattern closest to the viewing center) can be known, and the table 5 is determined from the x coordinate of the point on the pattern. The x coordinate of the visual field center in the coordinate system used as a reference can be known.

Since the variation in the field of view in the y direction is also sufficiently smaller than 100 µm, when the table 5 is moved to a predetermined position, the reference scale 13 can be reliably put in the field of view of the cameras A to C, and the captured reference scale From the image of (13), the y coordinate of the visual field center at this time can be known. The x-coordinate and y-coordinate of the visual field center thus obtained are used for correction when obtaining the coordinates of the measurement target point.

At intervals of at least one in the field of view of the cameras A to C, information of the coordinates of the location is added to the pattern of the reference scale 13 by a number or a figure coded, and the coordinates of the coordinates are taken from the captured image. The value may be read directly. In this way, the coordinates of the viewing center can be obtained only by the captured image without using the command value or the measured value of the camera position or the table position.

FIG. 4: shows the outline of the measurement procedure of the measurement object location of the board | substrate 12 using this position measuring apparatus 1, First, the board | substrate 12 is mounted in the table 5 (step n1), The measurement is performed as described later (step n2), the substrate 12 is recovered from the table 5 (step n3), and the process ends.

Next, the detail of the measurement in step n2 is applied and demonstrated to some specific examples.

FIG. 5: shows the measurement procedure of the coordinate of the reference mark P which is the measurement object location on the board | substrate 12 using camera A, and is a positional relationship of the table and camera in each step 1-3. And the content of the processing.

Here, the coordinate of the reference mark P means the center coordinate of the cross mark P of FIG. 2. The thing about the cross mark P is called the point P simply.

In Step 1, the camera 5 is moved in the x direction and the camera 5 is moved in the x direction while the camera moving mechanism is moved so as to be in a positional relationship assumed to enter the point P in the field of view of the camera A. 6, the point P of the board | substrate 12 is imaged with the camera A, making the positional relationship of the table 5 and the camera A into the state a shown in FIG.

Although it is preferable to perform the movement of the camera A and the table 5 simultaneously, you may carry out in order.

In addition, in the following description, although the measurement object location and the movement of the camera which image | photographs the reference scale 13 are demonstrated, the other camera which does not image | photograph is also taken to the x direction as needed so that the movement of the imaged camera may not be disturbed. To move.

In this step 1, when the point P is not in the visual field even if the point P is supposed to exist by the camera A, the camera A and the table 5 are moved. For example, as shown in FIG. 9, the area | region surrounding the initial imaging position Z shown by the oblique line is imaged by dividing | dividing into 8 times, for example until the point P enters a visual field. If the point P cannot be picked up still, the outside area is further divided into a plurality of images until the point P enters the field of view.

In addition, in FIG. 9, the table 5 is imaged by moving the table 5 once in the y direction from the first imaging position Z shown by an oblique line, and since the point P was not in the field of view, the camera A was again taken. The image was imaged by moving microscopically once in the x direction and the point P entered into the field of view, and the fine movement of the imaging position when the point P did not enter the field of view in the second imaging is represented by an imaginary line. .

Next, in Step 2 of FIG. 5, only the table 5 is moved in the y direction without moving the camera moving mechanism while the point P is picked up, that is, the camera A is stopped. ) And the camera A as the state b shown in FIG. 7, the reference scale 13 is captured by the camera A. FIG.

In step 3, the coordinates of the point P are calculated by image processing and calculation.

8 illustrates the field of view when the point P is imaged and the field of view when the image of the point P is imaged and the table 5 to explain the calculation of the coordinates of the point P according to this image processing and calculation. The positional relationship with) is shown schematically.

First, the image which picked up the point P is processed, and the coordinate (x1, y1) of the point P in the visual field coordinate system which makes the origin the visual center O shown in FIG. 8 (a) as an origin is calculated | required.

Next, the image of the reference scale 13 captured by moving only the table 5 without moving the camera A from the point P image-capturing state is processed, and the reference scale shown in Fig. 8B. The coordinates (X1, Y1) of the viewing center O in the table coordinate system at the time of imaging are obtained. At this time, the command values or measured values of the camera position in the x direction and the command values or measured values of the table position in the y direction are also used to find the coordinates (X1, Y1) of the viewing center (O). That is, since the coordinates of the x and y directions in the table coordinate system of the point on the pattern of the reference scale 13 in the picked-up image can be known based on the command value or the measured value, the position of this pattern and the viewing center O The coordinates (X1, Y1) of the visual field center O in the table coordinate system are obtained from the relationship.

Further, the measured value Δy of the amount of movement by the linear encoder is acquired as the amount of movement of the table 5 from imaging the point P to imaging the reference scale 13. When it is guaranteed that the command value of the table shift amount coincides with the measured value? Y by the linear encoder, this command value may be acquired as the shift amount of the table 5. In this case, the measured value of the movement amount of the table 5 by the linear encoder is acquired indirectly.

The x-coordinate x1 of the point P in the field-of-view coordinate system of FIG. 8 (a) to the x-coordinate X1 of the field-of-view center O in the table coordinate system obtained at the reference scale image picking up in FIG. 8 (b). The added value (X1 + x1) is the x-coordinate of the point P in the table coordinate system.

Table shift amount Δy and the point P in the field coordinate system of FIG. 8A in the y coordinate Y1 of the field of view center O in the table coordinate system obtained at the reference scale imaging obtained in FIG. 8 (b). The value (Y1 + Δy + y1) obtained by adding the y coordinate y1 of) is the y coordinate of the point P in the table coordinate system.

In addition, if the relative positional relationship between the table 5 and the base 3 is proved when measuring the movement amount of the table 5, the position of the point P which is a measurement target point based on the base 3 is determined. You can get it.

As described above, the coordinate (position) of the point P is obtained by using three types of information that use an image obtained by photographing the reference scale 13 and an amount of movement of the table 5 and an image photographed by the point P. will be.

By the image which image | photographed the reference scale 13 which is the 1st information of these three types of information, the position (X1, Y1) of the visual field of the camera A at the time of reference scale imaging can be calculated | required as mentioned above. . The position of this visual field is a position with respect to the position of the reference scale 13 at the time of reference scale imaging, ie, the position of the table 5 at that time. An error occurs in the position of the field of view due to an error in the movement amount of the camera A and a change in the attitude of the camera A, but even if there is an error in the position of the field of view, the field of view obtained from the image of the reference scale 13 captured By using the positions X1 and Y1, the error of the position of the visual field does not affect the position measurement result.

In other words, even if an error due to the movement amount of the camera and an error due to the attitude change occurs, the coordinates of the viewing position are determined from the positional relationship with the pattern of the reference scale 13 in the field of view by imaging the reference scale 13 on the table 5. By calculating (X1, Y1) and using these coordinates (X1, Y1), the influence on the position measurement result by the error of the position of the visual field is excluded.

If the amount of movement Δy of the table 5 between the reference scale image pickup and the point P image pickup as the second information and the coordinates X1 and Y1 of the visual field position as the first information are used, the reference scale The position of the visual field at the time of picking point P based on the position of the table 5 at the time of imaging can be calculated | required.

Moreover, the position (x1, y1) of the point P with respect to the visual field of the camera A at the time of point P imaging as mentioned above by the image which image | photographed the point P which is 3rd information. Can be obtained. Therefore, by using all the information, the position (X1 + x1, Y1 + Δy + y1) of the point P based on the position of the table 5 at the time of reference scale imaging can be obtained.

As mentioned above, when measuring the position of the point P which is a measurement target point on the board | substrate 12, the imaging-quantity 13 is imaged, and the movement amount error of the camera A and the attitude | position fluctuation of the camera A are made. It is possible to prevent the influence of the error of the field of view position caused by the camera from reaching the position measurement result. In addition, since the camera A is stationary with respect to the base 3 during the imaging of the point P and the reference scale 13 on the substrate 12, the error in the viewing position of the camera A during this time It can be prevented from occurring. Thereby, the measurement precision of the position of the point P which is a measurement object location improves.

In the position measuring method of FIG. 5 described above, the image of the reference scale 13 is imaged after the point P, which is the measurement target point, has been imaged. Although imaging may be considered, in that case, the mounting posture of the board | substrate 12 may shift | deviate so that it may rotate in surface, or the precision of the formation position of imaging object may be bad, etc. On the other hand, the point P may not be found, and the assumed position where the point P is found must be changed as shown in FIG. 9 as mentioned above.

In the case where the position of the camera A is moved along with this, an error in the field of view position occurs due to the movement amount error and the posture change in the camera A by moving the camera A. Again, it should be done again from the imaging of the reference scale 13. On the other hand, in the method of imaging the reference scale 13 after imaging the point P, when the point P is not found in the visual field which put the assumed position of the point P, the table 5 and a camera Move point one or both of (A) little by little to search for point P, and move the reference scale 13 by moving only the table 5 without moving the camera A from the position where the point P can be picked up. Since imaging may be performed, it is not necessary to perform imaging of the reference scale 13 again.

FIG. 10: is a figure which shows the measurement procedure of the coordinate of the reference marks P, Q, R, S of the board | substrate 12, a related dimension, and an angle using camera A. FIG.

As shown in FIG. 2, the points P and Q and the points R and S are two measurement object points spaced apart in the moving direction of the table 5, respectively. The imaging is performed in the order of R and S).

First, similarly to Fig. 5 described above, in Step 1, the point P as the first measurement target point is captured by the camera A as the state a in Fig. 6, and in Step 2, the camera moving mechanism is moved. Without moving the camera A in the x direction, only the table 5 is moved in the y direction to perform the first movement, and the reference scale 13 is performed by the camera A in the state b of FIG. Is picked up and the 1st image of the reference scale 13 is acquired.

Next, in step 3, the second movement is performed by moving only the table 5 in the y direction without moving the camera moving mechanism, i.e., without moving the camera A in the x direction. ) And the position A of the camera A as state c shown in FIG. 11, the point Q which is a 2nd measurement target point is imaged with the camera A. FIG.

At this time, if there is no point Q in the field of view of the camera A, the point A is moved by moving the camera A and the table 5 similarly as described with reference to FIG. Search for images.

At the time of searching for the point Q, when the camera A is microscopically moved in the x direction to capture the point Q, the process moves to step 4, and only the table 5 is moved in the y direction to perform the third movement. With the positional relationship between the table 5 and the camera A as the state b 'shown in FIG. 12, the reference scale 13 is imaged with the camera A, and a second image of the reference scale 13 is acquired. Then, it moves to step 5.

In addition, when searching the point Q, when the table 5 was microscopically moved to the y direction and the point Q was imaged, the cumulative amount which added the fine powder to the movement amount (second movement amount) of the said 2nd movement is accumulated. Let the movement amount be a 2nd movement amount.

In the step 3, when the point Q exists in the field of view of the camera A and there is no need for a search, or when the search is performed but the camera A is not moved, the camera A steps. Since the reference scale 13 is not moved as it is in 2, the step 4 in which the reference scale 13 is captured by the camera A is skipped, and the process moves to step 5.

The coordinates of the points P and Q separated in the moving direction of the table 5 are calculated in step 9 described later.

Next, similarly to the points P and Q with respect to the points R and S, in step 5, the camera A is moved in the x direction, and the table 5 is moved in the y direction so that the table 5 ) And the position of the camera A as the state d shown in FIG. 13, the point A as the first measurement target point is captured by the camera A. FIG.

Next, in Step 6, only the table 5 is moved in the y direction (first movement) without moving the camera A in the x direction, and the positional relationship between the table 5 and the camera A is shown. In the state e shown in 14, the reference scale 13 is imaged with the camera A. FIG.

Next, in Step 7, only the table 5 is moved in the y direction (second movement) without moving the camera A in the x direction, and the positional relationship between the table 5 and the camera A is determined. With the state f shown in FIG. 15, the point S is imaged with the camera A. FIG. At this time, when there is no point S in the field of view of the camera A, similarly to FIG. 9 mentioned above, the camera A and the table 5 are moved, and the point S is searched and imaged.

When the camera A is microscopically moved in the x direction when searching for this point S, the process moves to step 8, and only the table 5 is moved in the y direction (third movement) so that the table 5 and With the positional relationship of the camera A as the state e 'shown in FIG. 16, the reference scale 13 is imaged with the camera A, and it moves to step 9. FIG.

In addition, when the point Q is imaged by moving the table 5 in the y direction when searching for the point S, the cumulative addition of the fine content to the movement amount (second movement amount) of the second movement is performed. Let the movement amount be a 2nd movement amount.

In the step 7, when the point S exists in the field of view of the camera A and there is no need for searching, or when the searching is performed but the camera A is not moved, the camera A is checked in step 6 Since the reference scale 13 is not moved as it is, the step 8 in which the reference scale 13 is captured by the camera A is skipped, and the process moves to step 9.

In Step 9, the coordinates of the points P and Q are calculated as described below. That is, in step 3, when the point Q exists in the field of view of the camera A, and it does not need to search, the picked-up image of the point P and Q by the camera A, the camera A The coordinates of the points P and Q are calculated in the same manner as in FIG. 8 described above using the first image of the reference scale 13 and the first movement amount and the second movement amount of the table 5 according to FIG. .

In addition, in said step 3, the point Q does not exist in the visual field of the camera A, the point Q is searched, and at that time, the table 5 is moved in the y direction, and the point Q is made into it. At the time of image pick-up, the coordinates of points P and Q are computed using the cumulative movement amount which added the fine powder to the said 2nd movement amount as a 2nd movement amount.

In addition, in said step 3, the point Q does not exist in the visual field of the camera A, the point Q is searched, and at that time, the camera A is moved in the x direction and the point Q is moved. At the time of imaging, the picked-up image of the point P and Q by the camera A, the 1st and 2nd image of the reference scale 13, and the 1st, 2nd and 3rd movement amounts of the table 5 were measured. Using this, the coordinates of the points P and Q are calculated.

Similarly, the coordinates of the points R and S are also calculated.

In step 10, the angle formed by the two straight lines in the straight line connecting the dimension between each reference mark and each reference mark is calculated from the coordinates of each calculated point.

For example, the distance (dimension) between the reference marks P and Q is calculated from each coordinate of the reference marks P and Q, or, for example, a straight line connecting the reference marks P and Q and the reference mark ( The angle formed by the straight lines connecting Q and S), that is, the orthogonality, is calculated.

Thus, by calculating the dimension between the reference marks P, Q, R, and S on the board | substrate 12, and the angle which the straight line which connects them forms, the distortion and orthogonality of the pattern on a board | substrate can be grasped | ascertained.

FIG. 17 is a diagram illustrating a procedure of measuring the coordinates of the reference marks S and Q of the substrate 12 using the cameras A and B as the first and second cameras.

The points S and Q as the first and second measurement target points are two points spaced apart in the direction perpendicular to the moving direction of the table 5.

First, in Step 1, the cameras A and B are moved in the x-direction so as to be in a positional relationship where the points S and Q are respectively entered into the visual fields of the cameras A and B, and the table 5 is moved. Is moved in the y direction so that the positional relationship between the table 5 and the cameras A and B is set to the state g shown in Fig. 18, and the point A as the first measurement target point is the camera A as the first camera ( While imaging S), the point Q as a 2nd measurement object location is imaged with the camera B as a 2nd camera.

Next, in Step 2, only the table 5 is moved in the y direction without moving the camera moving mechanism, that is, without moving the cameras A and B, and thus the table 5 and the cameras A and B are moved. 19, the reference scale 13 is imaged with cameras A and B as 1st and 2nd cameras, respectively, and the 1st and 2nd image is acquired. In Step 3, the image of the point S, Q by the cameras A and B, the first and second images of the reference scale 13 by the cameras A and B, and the amount of movement of the table 5 The coordinates of the points Q and S are calculated by using image processing and calculation.

FIG. 20 is a diagram corresponding to FIG. 5 showing a procedure of measuring coordinates in the substrate coordinate system of the point T on the substrate 12 shown in FIG. 21 using the cameras A to C. FIG.

The point T on the board | substrate 12 is a characteristic point, such as the center of the figure selected from the wiring pattern, the corner of a figure, etc., for example.

First, in Step 1, the camera moving mechanism is moved in the x direction by moving the camera moving mechanism so as to assume an assumed positional relationship where the points S and Q are respectively entered in the field of view of the cameras A and C. While the table 5 is moved in the y direction, the positional relationship between the table 5 and the cameras A and C is set to the state i shown in FIG. 21, and the point A is captured by the camera A. The point Q is picked up by the camera C. FIG.

In this step 1, the camera B is also preferably moved to the position where the point T is assumed to enter the field of view only by the movement of the table 5 at the same time as the movement of the cameras A and C. Do. That is, when there is a possibility that the viewing position of the cameras A and C may be changed by the movement in the x direction of the camera B, for example, vibration caused by the movement of the camera B is caused by the cameras A and C. In the case of affecting the visual field position of the camera), when the cameras A and C are moved in the x direction, the cameras B are also moved in the x direction at the same time. Afterwards, it is possible to prevent variations in the viewing positions of the cameras A and C.

Next, in Step 2, the table 5 is moved in the y direction to perform the first movement, and the positional relationship between the table 5 and the camera B is set to state j shown in FIG. The point T is picked up by B).

Next, in Step 3, the second movement is performed by moving only the table 5 in the y direction without moving the camera moving mechanism, that is, without moving the cameras A to C. With reference to the state k shown in FIG. 23 and the positional relationship of the cameras A-C, the reference scale 13 is imaged with cameras A-C, respectively. In step 4, a table is processed by image processing and arithmetic. The coordinates of the points Q and S and the point T in the coordinate system are calculated.

Next, in step 5, the board coordinate system with respect to the table coordinate system is determined using the coordinates of the points Q and S, and then, the coordinates of the point T obtained from the table coordinate system are converted into the board coordinate system. Converting the coordinates of the point T into the substrate coordinate system is because the design coordinates of the point T are originally displayed in the substrate coordinate system, so if the actual coordinates of the point T are converted into coordinates in the substrate coordinate system, This is because the actual coordinates of the point T can be compared directly with the coordinates in the design, which is convenient.

Here, the conversion from the table coordinate system to the substrate coordinate system will be described.

If the xy coordinates in the board coordinate system are already known about the point Q and the point S which are two points on the board | substrate 12, by measuring the xy coordinates in the table coordinate system of those points Q and S, both coordinate systems are measured. Since the angle formed by the positional relationship between the origins of the coordinates (for example, the coordinates of the table coordinates of the origin of the substrate coordinate system) and the coordinate axes of the two coordinate systems can be obtained, the coordinate transformation between the two coordinate systems can be used using these. However, for example, when the point Q is provided as the coordinate origin in the board | substrate coordinate system, even if the design coordinate of the board | substrate coordinate system in the board | substrate coordinate system is (Sx, 0), by the manufacturing error, the point (S) Since the distance from the point Q may actually be slightly off Sx, the coordinates of the point S are not known. However, by defining the line connecting the point Q and the point S as the x coordinate axis in the substrate coordinate system, the angle formed by the x axis of the table coordinate system and the x axis of the substrate coordinate system can be obtained. Therefore, in this example, since the coordinates of the table coordinate system of the point Q (that is, the origin of the substrate coordinate system) and the x-axis of both coordinate systems can be obtained, the coordinate transformation between the two coordinate systems can be used. Can be.

The measurement procedure of FIG. 20 is a method of obtaining the position and attitude of the pattern on the substrate 12 using at least two reference marks selected from the imageable patterns on the substrate 12 such as the cross marks S and Q. I can figure it out.

In addition, in the said measurement procedure of FIG. 20, the 1st measuring object point (point S) on the board | substrate 12 is made into a 1st camera (camera A), and the 2nd measuring object point (point Q) is made into 2nd. Imaging with a camera (camera C), moving the table 5 without moving each moving mechanism supporting the first and second cameras, and imaging the reference scale 13 with the first and second cameras, respectively. , The image of the 1st and 2nd measurement object points obtained by measuring the movement amount of the table 5 from the imaging of the 1st and 2nd measurement object point to the imaging of the reference scale 13 with the movement amount measuring device, It can be grasped as a method of obtaining the positions of the first and second measurement target points using the first and second images of the reference scale 13 and the amount of movement of the table 5 respectively captured by the first and second cameras. have.

In addition, in the said measurement procedure of FIG. 20, the 1st measuring object point (point S) on the board | substrate 12 is imaged with a 1st camera (camera A), and the moving mechanism which supports a 1st camera is 1st. The first movement is made to the table 5 without moving as it was when the imaging of the measurement target point of the image was taken, and the second measurement target point (point T) on the substrate 12 was moved to the second camera (camera B). The image is taken, the first movement amount of the table 5 in the first movement is measured by a movement amount measuring device, and the second movement is performed on the table 5 without moving the respective movement mechanisms supporting the first and second cameras. The reference scale 13 is imaged with the 1st and 2nd camera, respectively, and the 2nd movement amount of the table 5 in a 2nd movement is measured with the movement amount measuring device, and 1st and 1st obtained 1st of the reference scale 13 image | photographed with the image of 2 measurement object points, and the 1st and 2nd camera, respectively. The can be grasped as a method using the first and the second movement amount of an image and a table 5 of the second to obtain the first and second positions of the measurement object point of the.

It is a top view corresponding to FIG. 2 of the position measuring apparatus of other embodiment of this invention.

The difference from the above-described embodiment shown in FIG. 2 is that in addition to the reference scale 13 (referred to as the reference scale 13a in FIG. 24) shown in FIG. 2, the reference scale 13b is used as a substrate ( 12) is inserted and provided in the position on the opposite side to the reference scale 13a on the table 5. As shown in FIG.

The position of the reference scale 13b with respect to the reference scale 13a is measured beforehand, and when the reference scale 13b is imaged, the position of the visual field at that time is calculated based on the reference scale 13a. . Therefore, the reference scale 13b can be used in place of the reference scale 13a at any time. Therefore, the measurement procedure is similar to each measurement procedure so far, and when only the measurement target point is close to the reference scale 13b, instead of imaging the reference scale 13a as appropriate, the image is captured by the reference scale 13b. By reducing the amount of movement of the table 5, the time required for the measurement can be shortened.

As another embodiment, by using a position measuring device that supported more cameras on each camera moving mechanism, images of the measurement target points corresponding to the number of cameras are sequentially photographed while moving a table, and the Imaging may be performed at a common table position.

Moreover, when providing a some camera in a position measuring apparatus, you may make it distribute | distribute installation of a camera moving mechanism to both sides of the mount 6, ie, both sides of a table movement direction so that the mount 6 may be fitted. By doing so, it is easy to design the camera moving mechanisms provided on different sides of the mount 6 so that interference with respect to the moving range does not occur, so that the independence of the movement between the cameras can be increased.

In addition, a plurality of mounts may be provided to distribute the installation of the camera moving mechanism to the mounts. By doing so, it is not only easy to prevent interference of the moving range with respect to the camera moving mechanisms provided on different mounts, and the camera moving mechanisms provided on the other mount even when the camera moving mechanisms provided on one mount are moved. Since it is easy to prevent the field of view of the camera supported by the camera from being changed, the degree of freedom regarding the procedures of moving and imaging the camera moving mechanism and the table is increased.

However, in the case where the cameras are provided on both sides of the mount or the cameras are provided on a plurality of mounts as described above, if the field of view of those cameras is at a different position in the moving direction of the table, By setting the reference scale or increasing the reference scale in the direction of the table movement, allowing each camera to see different reference scales or different parts of one reference scale at the same table position, or dividing the imaging of the reference scale into multiple timings In the meantime, you need to move the table, or consider. When the imaging of the reference scale is divided into a plurality of timings and the table movement is performed in the meantime, the movement amount must also be used when the position of the measurement target point is obtained.

According to the present invention, when measuring the position of the measurement target point on the substrate, the influence of the error of the movement amount of the camera and the error of the field of view of the camera caused by the variation of the attitude of the camera caused by the imaging of the reference scale does not fall short of the position measurement result. In addition, since the camera is stationary with respect to the base during the imaging of the measurement target point and the reference scale on the substrate, it is possible to prevent an error in the viewing position of the camera at this time. Thereby, the measurement precision of the position of a measurement object location improves.

Industrial availability

The present invention is useful for, for example, dimensional inspection of a substrate.

Claims (11)

A base, a table moving in a first direction from the base, a movement amount measuring device for measuring the amount of movement of the table, a mount fixed to the base, a first direction provided on the mount, A camera moving mechanism having a second direction perpendicular to the movable direction, a camera supported by the camera moving mechanism and moving in a second direction from above the base, and a table in a direction perpendicular to the moving direction of the table Preparing a position measuring device having a reference scale that is provided on the image and gives information on the visual field position of the camera in the captured image when the image is captured by the camera, The board | substrate made into a measurement object is mounted to the said table, One of the measurement target points on the substrate and the reference scale is picked up by the camera, Only the table is moved without moving the camera movement mechanism as it is when the imaging is performed, and the other part of the measurement target point and the reference scale on the substrate is imaged with the camera. The movement amount of the table in the movement is measured by the movement amount measuring instrument, A position measuring method is obtained by using the obtained image of the measurement target point, the image of the reference scale, and the movement amount of the table. The method of claim 1, Prepare the position measuring device, The board | substrate made into a measurement object is mounted to the said table, The measurement object point on the said board | substrate is imaged with the said camera, The camera moving mechanism is moved without moving as it is when the imaging is performed, and only the table is moved to capture a reference scale with the camera. The movement amount of the table in the movement is measured by the movement amount measuring instrument, A position measuring method is obtained by using the obtained image of the measurement target point, the image of the reference scale, and the movement amount of the table. The method of claim 2, Prepare the position measuring device, The board | substrate made into a measurement object is mounted to the said table, The 1st measurement object location on the said board | substrate is imaged with the said camera, The first scale is moved to the table without moving the camera moving mechanism to capture a reference scale with the camera to obtain a first image of the reference scale, The first movement amount of the table in the first movement is measured by the movement amount measuring device, A second surface is moved to the table without moving the camera moving mechanism, and the substrate surface portion assumed to have a second measurement target point is imaged with the camera. If the second measurement target point is contained in the image picked up, the image is adopted as the image of the second measurement target point, If the second measurement target point does not enter the picked-up image, the imaging is repeated by moving the table or camera moving mechanism until the imaging of the second measurement target point is successful, When the second movement amount of the table is measured by the movement amount measuring device, or when the table is fine-tuned, the accumulated movement amount which is added to the second movement amount by the fine powder is measured by the movement amount measuring device as a second movement amount, When the camera movement mechanism is moved until the imaging of the second measurement target point is successful, the third movement is made to the table without moving the camera movement mechanism from the state when the imaging of the second measurement target point is successful. Image of the reference scale to obtain a second image of the reference scale, The third movement amount of the table is measured by the movement amount measuring instrument, The obtained images of the first and second measurement target points, the first image of the reference scale and the first and second movement amounts of the table, and the second image of the reference scale and the third movement amount of the table, if present And the positions of the first and second measurement target points are obtained. The method of claim 2, A first camera moving mechanism and a second camera moving mechanism that can move independently of each other, a first camera supported by the first camera moving mechanism, and a second camera supported by the second camera moving mechanism. And the position measuring device in which the visual fields of the first and second cameras are separated from each other in a direction perpendicular to the moving direction of the table, The board | substrate made into a measurement object is mounted to the said table, The first measuring object point on the substrate is photographed with a first camera, and the second measuring object point is photographed with a second camera, The table is moved without moving the first and second camera moving mechanisms, and the reference scale is imaged by the first and second cameras, respectively. The movement amount of the table in the movement is measured by the movement amount measuring instrument, The 1st and 2nd measurement object point using the obtained image of the 1st and 2nd measurement object point, the 1st and 2nd image of the reference scale imaged with the 1st, 2nd camera, and the movement amount of a table, respectively. Position measuring method, characterized in that to obtain the position of. The method of claim 2, A first camera moving mechanism and a second camera moving mechanism that can move independently of each other, a first camera supported by the first camera moving mechanism, and a second camera supported by the second camera moving mechanism. It is equipped with the said position measuring apparatus which the visual field of the 1st and 2nd camera mutually spaces in the direction perpendicular to the movement direction of a table, The board | substrate made into a measurement object is mounted to the said table, The first measurement target point on the substrate is picked up by a first camera, The first camera moving mechanism is subjected to the first movement to the table without being moved as it is when the imaging is performed, and the second measurement target point on the substrate is imaged by the second camera. The first movement amount of the table in the first movement is measured by the movement amount measuring device, The second scale is moved to the table without moving the first and second camera moving mechanisms, and the reference scale is imaged by the first and second cameras, respectively. The second movement amount of the table in the second movement is measured by the movement amount measuring device, The first and second images of the first and second measurement target points obtained, the first and second images of the reference scales respectively photographed with the first and second cameras, and the first and second movement amounts of the table are used. The position measuring method is obtained by obtaining a position of a second measurement target point. The method according to any one of claims 1 to 5, On the board | substrate, the pattern which can be imaged is provided, The measurement target point on the substrate is at least two reference marks selected from the pattern, The position measuring method characterized by using the calculated | required position of the at least 2 reference mark calculated | required, and the position and attitude | position of the said pattern further. The method according to any one of claims 1 to 5, On the board | substrate, the pattern which can be imaged is provided, The measurement target point on the substrate is a first point and a second point selected from the pattern, The distance between the 1st point and the 2nd point is calculated | required using the calculated | required position of the 1st point and the 2nd point. The method according to any one of claims 1 to 5, On the board | substrate, the pattern which can be imaged is provided, The measurement target point on the substrate is the first, second, third and fourth points selected from the pattern, The angle formed by a straight line connecting the first point and the second point and a straight line connecting the third point and the fourth point using the obtained positions of the first, second, third and fourth points. Obtaining a position, characterized in that for obtaining. With expectation, A table moving in a first direction on the base, A movement amount measuring device for measuring the movement amount of the table; Trestle fixed to the expectations, A camera moving mechanism provided in the mount and having a second direction orthogonal to the first direction as the movable direction; A camera supported by the camera moving mechanism and moving in a second direction above the base; And a reference scale provided on the table along a direction perpendicular to the moving direction of the table, and giving a reference scale in the picked-up image when photographing with the camera. The method of claim 9, The said reference scale is provided with the area | region where the board | substrate on the table should be mounted, and is provided in the both sides of the movement direction of a table, The position measuring apparatus characterized by the above-mentioned. The position measuring device according to claim 9 or 10, A control device connected to the position measuring device and capable of transmitting information to each other; The control device includes a computer that executes a control program, The control program, Any one of the measurement target point on the substrate mounted on the table of the position measuring device and the reference scale is imaged with the camera, Only the table is moved without moving the camera movement mechanism as it is when the imaging is performed, and the other part of the measurement target point and the reference scale on the substrate is imaged with the camera. The movement amount of the table in the movement is measured by the movement amount measuring instrument, And a step of obtaining the position of the measurement target point using the obtained image of the measurement target point, the image of the reference scale, and the movement amount of the table.

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