JP2010019742A - Straightness measurement method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique easily and precisely measuring straightness of a stage moving in a prescribed direction while suppressing the costs for measurement. <P>SOLUTION: The central position of a straight linear pattern 21 in an X axis direction at each point is measured when a pattern body 2 having the straight linear pattern 21 on its upper surface is moved in Y axis direction for each of the cases when the pattern body 2 is fixed at a first position POS1 of the stage 1 and when it is fixed at a second position POS2 shifted by a prescribed length parallel to the moving direction of the stage 1 (+Y direction). By obtaining the difference between the obtained measurement results D1, D2, the displacement amount of the pattern 21 itself in the X axis direction is canceled out, and the amount of variation of the position of the stage 1 during movement at each position in the X axis direction is calculated. Further, by cumulatively adding the differential results, the displacement amount (movement errors, straightness) at each position in the X axis direction of the stage 1 moving in the (+Y) direction is calculated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for measuring the straightness of a support that moves in a predetermined direction.

  2. Description of the Related Art Conventionally, in a drawing apparatus that draws a pattern on a semiconductor substrate or a glass substrate, drawing on the entire substrate is performed by moving a stage on which the substrate is placed. In such a drawing apparatus, a slight deviation from the moving axis of the stage (movement error in a direction orthogonal to the moving direction (lateral direction, etc.)) due to the processing accuracy of the guide for guiding the stage in the moving direction, etc. Occurs. Therefore, when drawing a fine pattern, the influence of such a movement error on the drawing process cannot often be ignored.

  Thus, several techniques for measuring the movement error (straightness) of the moving stage have been proposed (Patent Documents 1 and 2). For example, in Patent Document 1, laser light is irradiated from a laser length measuring device toward a stage mirror provided on a side surface along the moving direction of the stage, and interference between reflected light from the stage mirror and the original laser light occurs. A technique for measuring the position and yawing angle in the moving direction of the stage is disclosed.

  Patent Document 2 discloses an adjustment mechanism that rotates a plane mirror attached to the side of the stage relative to the stage. According to this, when the stage is moved, the reflected light from the plane mirror can be reliably received by the light receiving unit.

JP 2005-90983 A JP 2008-91785 A

  However, in Patent Documents 1 and 2, the processing accuracy of the flatness of the mirror and the mounting accuracy are important in measuring the straightness of the stage. For example, if there is a problem with the flatness of the mirror, the measurement result of the laser length measuring instrument can accurately measure the straightness of the stage because the error of the mirror flatness is added to the movement error of the stage. It becomes difficult. Even when the mounting accuracy is poor, it is difficult to accurately measure the straightness of the stage.

  Further, the above technique directly measures the amount of displacement in the direction perpendicular to the moving direction of the stage, so that it is necessary to prepare an expensive laser length measuring device, and there is a problem that the measurement cost is high.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique for easily and accurately measuring the straightness of a moving stage while suppressing the cost required for measurement.

  In order to solve the above problems, the invention of claim 1 is a straightness measurement method for measuring the straightness of a support when the support that supports the object to be processed is moved along the first direction. A first fixing step of fixing the measurement reference object at the first position of the support, and the support in which the measurement reference object is fixed at the first position in the first fixing step. A first measurement step of measuring a displacement amount of the measurement reference object in a second direction substantially orthogonal to the first direction while moving along the direction, and at least the first direction from the first position. A second fixing step of fixing the measurement reference object to a second position of the support body shifted by a predetermined length; and the support in which the measurement reference object is fixed at the second position in the second fixing step. The second side of the measurement reference object while moving the body along the first direction Taking a difference between the second measurement step of measuring the displacement amount of the measurement reference object and the displacement amount of the measurement reference object measured in the first measurement step and the second measurement step. A displacement amount calculating step of offsetting the displacement amount in the second direction and calculating the displacement amount in the second direction of the support when the support is moved along the first direction. Features.

  The invention of claim 2 is the straightness measurement method according to the invention of claim 1, wherein the measurement reference object is the first reference measurement step and the second fixation step. It includes a pattern extending at least in the first direction when fixed at the first position and the second position.

  Further, the invention of claim 3 is a straightness measurement method according to the invention of claim 2, wherein in the first measurement step and the second measurement step, the displacement of the center position of the pattern in the second direction. It is characterized by measuring each quantity.

  According to a fourth aspect of the present invention, there is provided a straightness measuring apparatus for measuring the straightness of a support when the support that supports the object to be processed is moved along the first direction. A moving means for moving in one direction, a measurement reference object fixed to the support, and the first direction when the support to which the measurement reference is fixed is moved in the first direction. Displacement amount measuring means for measuring the displacement amount of the measurement reference object in a second direction perpendicular to the first position, first position fixing means for fixing the measurement reference object to the first position of the support, and the measurement reference object Is fixed at the first position by a second position fixing means for fixing the support body to a second position shifted from the first position by a predetermined distance along the first direction. The result of measuring the displacement of the predetermined measurement reference object and the second position By taking the difference from the measured displacement amount of the measurement reference object, the displacement amount of the measurement reference object itself in the second direction is offset, and the support is moved along the first direction. Displacement amount calculating means for calculating a displacement amount in the second direction of the support when moved is provided.

  According to the first to fourth aspects of the invention, when measuring the straightness (movement error) of the moving stage, the measurement reference object is fixed at the first position and the second position is fixed. , The measurement result of the position of the moving measurement reference object in the second direction is acquired, and the displacement amount of the measurement reference object itself in the second direction is canceled from the measurement result. Accordingly, since it is possible to suppress the requirement for the shape accuracy of the measurement reference object, it is possible to easily and accurately measure the straightness of the moving stage while reducing the processing cost of the measurement reference object. In addition, since the position detecting mechanism that directly measures the amount of displacement of the moving stage in the second direction orthogonal to the moving direction is not used, the cost required for the measurement can be suppressed.

  According to the second aspect of the present invention, the measurement reference object is fixed to the stage so that the pattern of the measurement reference object extends in the moving direction of the stage, so that the position of the pattern when the stage is moved is measured. By doing so, the straightness of the moving stage can be measured easily and accurately.

  According to the invention described in claim 3, since the center position of the pattern is measured, the measurement error in the pattern position measurement can be reduced.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.

<1. Embodiment>
<1.1. Configuration and Function>
FIG. 1 is a perspective view showing an outline of a measuring apparatus 100 according to an embodiment of the present invention.

  In FIG. 1, for the sake of illustration and explanation, the Z-axis direction is defined as the vertical direction and the XY plane is defined as the horizontal plane, but these are defined for convenience in order to grasp the positional relationship. The directions described below are not limited. The same applies to the following drawings.

[Schematic configuration]
The measuring apparatus 100 is an apparatus for measuring the straightness of the stage 1 in the X-axis direction when the stage 1 is moved in the Y-axis direction. As shown in FIG. 3, the moving mechanism 4, the stage position detection mechanism 5, and the control part 6 are mainly provided. Such a measuring apparatus 100 is, for example, an exposure apparatus that performs patterning on a substrate to be processed such as a glass substrate on which a photosensitive layer is formed, or a coating that forms a photosensitive layer by applying a resist solution to a glass substrate or the like. It is installed in a device.

[Stage 1]
Stage 1 is an object to be inspected of measuring apparatus 100. The stage 1 has a substantially rectangular parallelepiped outer shape, and a mounting surface 10 that supports a substrate to be processed (object to be processed) is formed in a substantially horizontal region on the upper surface of the stage 1 in an exposure apparatus or a coating apparatus. Has been. That is, the stage 1 has a function as a support in the present embodiment.

  The mounting surface 10 is provided with two pin insertion holes H1 and H2 along the X-axis direction at a position biased toward the (+ Y) side, and one pin insertion hole at a position biased toward the (+ X) side. H3 is provided.

  In addition, although illustration is abbreviate | omitted, in the upper surface of the mounting surface 10, the several suction hole is distributed and provided. These suction holes are connected to a vacuum pump through a pipe and are provided to suck and hold the substrate to be processed on the placement surface 10. In the present embodiment, the suction hole is used to suck a pattern body 2 (described later) onto the mounting surface 10 when measuring the straightness of the moving stage 1.

  FIG. 2 is a cross-sectional view of the stage 1 showing a state in which the T-shaped pin P1 is inserted into the pin insertion hole H1. FIG. 3 is a cross-sectional view of the stage 1 showing a state in which the I-shaped pin P2 is inserted into the pin insertion hole H1.

  As shown in FIG. 2, the T-shaped pin P <b> 1 has a disk-shaped head with a diameter L <b> 1 and is approximately the same as the diameter of the circular opening of the pin insertion holes H <b> 1 to H <b> 3 on the opposite side to the head. Columnar leg portion having a diameter L2. Moreover, as shown in FIG. 3, the I-shaped pin P2 has a cylindrical main body having a diameter L2.

  The T-shaped pin P1 and the I-shaped pin P2 are fixed at respective positions on the mounting surface 10 by being inserted into the pin insertion holes H1 to H3, and the outer peripheral portion of the portion protruding upward from the mounting surface 10 Then, the mounting position of the pattern body 2 is positioned by contacting the pattern body 2. In addition, the outer periphery of the part inserted into the pin insertion holes H1 to H3 of each pin and the inner periphery of the pin insertion holes H1 to H3 have a bolt / nut structure, and these pins are screwed together to place each pin on the mounting surface 10. You may fix to each position.

  FIG. 4 is a top view of the stage 1 showing a state in which the pattern body 2 is arranged at the first position POS1. FIG. 5 is a top view of the stage 1 showing a state in which the pattern body 2 is disposed at the second position POS2.

  In the present embodiment, as shown in FIG. 4, the T-shaped pin P1 is inserted into each of the pin insertion holes H1 to H3, and the end of the pattern body 2 is brought into contact with each pin. The placement position of the pattern body 2 at this time is the first position POS1. Further, as shown in FIG. 5, the I-shaped pin P2 is inserted into the pin insertion holes H1 and H2, the T-shaped pin P1 is inserted into the pin insertion hole H3, and the pattern body 2 is brought into contact with each pin. The position of the pattern body 2 at this time is the second position POS2.

  Since the outer diameters of the portions of the T-shaped pin P1 and the I-shaped pin P2 that are in contact with the substrate are the diameter L1 and the diameter L2, respectively (see FIGS. 2 and 3), the second position POS2 shown in FIG. Is a position shifted in parallel to the (+ Y) direction by a predetermined length (deviation amount L3 (= (L1-L2) / 2)) from the first position shown in FIG.

  Thus, the mounting position of the pattern body 2 on the mounting surface 10 can be changed by appropriately determining the insertion positions of the T-shaped pin P1 and the I-shaped pin P2 having different diameters L1 and L2. The positioning mechanism for the pattern body 2 is not limited to the one using the above pins, and may be realized by other methods.

[Pattern 2]
Returning to FIG. 1 again, the pattern body 2 has a square plate shape, and when the flatness of the stage 1 is measured, a predetermined position (first position POS1, first position) on the mounting surface 10 is measured. 2 positions POS2) are fixedly arranged. Further, the upper surface of the pattern body 2 has a substantially linear pattern 21 extending along the moving direction (Y-axis direction) of the stage 1 when the pattern body 2 is disposed at the predetermined position. The material of the pattern body 2 is not particularly limited, but the pattern 21 portion and the non-pattern 21 portion of the pattern body 2 can be identified in image processing when captured by the line camera 3 described later. Made of material.

  In the present embodiment, while the stage 1 is moved in the Y-axis direction, the amount of displacement in the X-axis direction of the pattern 21 on the pattern body 2 is measured by the line camera 3 or the like, so that the stage 1 being moved is moved. Measure straightness. Therefore, in the present embodiment, although the displacement amount of the pattern 21 in the X-axis direction is a direct measurement target, the pattern 21 is in a fixed positional relationship with respect to the pattern body 2. This is substantially equivalent to measuring the amount of displacement of the body 2 in the X-axis direction. That is, in the present embodiment, the pattern body 2 is a measurement reference object.

[Line camera 3]
FIG. 6 is a diagram for explaining the imaging position of the pattern 21 by the line camera 3. The line camera 3 is fixed at a predetermined position on the placement surface 10 (see FIG. 1), and images the pattern 21 on the pattern body 2. As shown in FIG. 6, the line camera 3 includes a line sensor 31 having a plurality of light receiving elements arranged along a predetermined direction (here, the X-axis direction).

  In the measuring apparatus 100, the pattern 21 is imaged by the fixed line camera 3 while moving the stage 1 as the object to be measured in the (+ Y) direction. Therefore, the imaging positions (Y1) to (Ym) shown in FIG. 6 are originally the arrangement positions (fixed positions) of the line camera 3. However, for convenience of explanation, FIG. 6 shows a relative positional relationship between the pattern 21 and the imaging position of the line camera 3 when viewed from the stage 1.

  In the present embodiment, every time the stage 1 moves a predetermined distance in the (+ Y) direction, the line sensor 31 images the pattern 21 that moves in the (+ Y) direction. When this is seen from the coordinate system of the stage 1, as shown in FIG. 6, a plurality of imaging points ((Y1) to (Ym)) are set on the stage 1 for each imaging interval Dy.

  Data of the captured image ID of the pattern 21 captured by the line sensor 31 is sent to the control unit 6 described later. The captured image ID is processed by the control unit 6 and the center position of the pattern 21 is calculated. Then, based on the displacement amount in the X-axis direction of the center position of the pattern 21 while the stage 1 is moving, the displacement amount (movement error) in the X-axis direction of the moving stage 1 is calculated.

  Although the pattern 21 has been described as having a substantially linear shape, as shown in FIG. 6, there are cases where the pattern 21 is locally curved due to a processing error or the like. Therefore, the displacement amount of the center position of the moving pattern 21 in the X-axis direction is a value obtained by adding the displacement amount of the pattern 21 itself in the X-axis direction to the movement error of the stage 1.

  Here, the amount of displacement of the pattern 21 from the predetermined reference is the amount of positional deviation with respect to the Y axis of the center position at each position of the pattern 21 itself. That is, when the pattern 21 extends straight along the Y-axis direction, the amount of displacement of the pattern 21 itself in the X-axis direction is zero. As shown, it is difficult to form a substantially straight line on the pattern body 2.

  However, although details will be described later, in the present embodiment, the straightness of the stage 1 is calculated while offsetting the displacement amount of the pattern 21 itself in the X-axis direction. That is, the measuring apparatus 100 can accurately calculate the movement error (straightness) in the X-axis direction of the moving stage 1 even if the pattern 21 itself is not a straight straight line but is partially bent.

  In the present embodiment, the line sensor 31 is described as acquiring a captured image ID of a monochrome multi-gradation (for example, 4 bits = 16 gradations, 8 bits = 256 gradations) image expression using a plurality of bits. However, the configuration may be such that the image is acquired as a color multi-tone expression image. In the case of acquiring an image having a color multi-tone expression, monochrome multi-tone processing is appropriately performed when calculating the center position of the pattern 21.

[Movement mechanism 4]
Returning to FIG. 1 again, the moving mechanism 4 has a function of moving the stage 1 in the Y-axis direction in a horizontal plane. The moving mechanism 4 includes a Y-axis moving plate 41 that moves in the Y-axis direction, a linear motor 42 that extends along the Y-axis direction, and a Y-axis moving plate 41 that is provided on the lower surface of the Y-axis moving plate 41. The guide mechanism 43 which prescribes | regulates the movement of is provided. The Y-axis moving plate 41 moves in the Y-axis direction along the guide mechanism 43 by the operation of the linear motor 42.

  Since the stage 1 is provided on the upper surface of the Y-axis moving plate 41, the stage 1 moves along the Y-axis direction as the Y-axis moving plate 41 moves. Measuring apparatus 100 in the present embodiment measures a movement error (straightness) of stage 1 in the X-axis direction at this time.

  The moving mechanism 4 is not limited to the above-described configuration. For example, the moving mechanism of the stage 1 may be realized by a ball screw and a motor.

[Stage position detection mechanism 5]
Returning to FIG. 1 again, the stage position detection mechanism 5 mainly includes a laser length measuring device 51 and a corner cube 52 installed on the side surface of the stage 1 on the (+ Y) side. The laser length measuring device 51 includes a laser light source, a linear interference system, and a receiver (not shown), and detects (measures) the position of the stage 1 that is a detection target.

  The corner cube 52 is a combination of mirrors that reflect the laser light emitted from the laser length measuring device 51 so that three planar plates are perpendicular to each other. For example, the light incident on the inside of the corner cube 52 is reflected three times on each mirror surface, and as a result, returns to the original direction.

  The laser length measuring device 51 is disposed on the (+ Y) side of the stage 1, emits a light beam, and enters the corner cube 52 through a linear interference system. Then, the reflected light interferes with the original light beam by the linear interference system and is received by the receiver. Based on the output from the receiver, the position of the stage 1 in the Y-axis direction is detected with high accuracy.

  In the measurement apparatus 100, the stage position detection mechanism 5 detects the position of the stage 1 in the moving direction (Y-axis direction), but the present invention is not limited to this. For example, the linear motor 42 is provided with an encoder. Thus, the position of the stage 1 may be detected.

[Control unit 6]
FIG. 7 is a block diagram showing the connection between the control unit 6 and each component of the measurement apparatus 100. The control unit 6 mainly includes a CPU 61, a storage unit 62, a display unit 63, and an input unit 64, and is wired (or wireless) via the line camera 3, the moving mechanism 4, the stage position detection mechanism 5, and bus wiring. Connected).

  The CPU 61 performs calculations on various data stored in the storage unit 62 by reading and executing a program stored in the storage unit 62. Thus, the control unit 6 has a configuration as a general computer.

  The center position calculation unit 610, the change amount calculation unit 611, and the integration processing unit 612 are functional blocks that are realized by the CPU 61 operating according to a program stored in the storage unit 62 or the like.

  FIG. 8 is a diagram for explaining a procedure for obtaining the center position of the pattern 21 in the X-axis direction based on the captured image ID. The center position calculation unit 610 extracts two extreme points exceeding a predetermined threshold by analyzing the distribution of gradation values of the captured image ID acquired by the line sensor 31 and performing a differentiation process. The positions of the two extreme points correspond to edge portions on the image in the X-axis direction of the pattern 21.

  Then, the center position calculation unit 610 calculates the position (center position) of the intermediate point between the two extracted inflection points. Note that the position of the intermediate point calculated by the image processing is position information on the image data (that is, virtual), and thus is converted into position information of the physical pattern 21 by a predetermined calculation process. Thus, since the center position calculation unit 610 calculates the physical center position of the pattern 21 at each position based on the captured image ID captured at each imaging point, the measurement result of the position of the pattern 21 is obtained. Measurement error can be reduced.

  Although details will be described later, in the present embodiment, the measurement result D1 of the center position of the pattern 21 and the pattern body 2 when the pattern body 2 is fixed to the first position POS1 and the stage 1 is moved are displayed. The measurement result D2 of the center position of the pattern 21 when the stage 1 is moved while being fixed at the second position POS2 is acquired and stored in the storage unit 62.

  The change amount calculation unit 611 calculates the change amount of the position in the X-axis direction between the imaging points of the stage 1 that is moving in the (+ Y) direction based on the measurement results D1 and D2. More specifically, a difference result D3 in which the amount of displacement of the pattern 21 itself from the predetermined reference is canceled is obtained by taking the difference between the measurement results D1 and D2.

  In the present embodiment, since the straightness of the moving stage 1 is measured by canceling out the displacement amount of the pattern 21 itself in the X-axis direction, it is possible to suppress the requirement for the shape accuracy of the pattern 21 itself.

  The integration processing unit 612 performs integration processing based on the change amount at each imaging point calculated by the change amount calculation unit 611. In the integration result D4 acquired in this way, movement error (displacement amount from a predetermined reference position) information of the stage 1 moving in the (+ Y) direction in the X-axis direction is described.

  Thus, in the present embodiment, the straightness of the moving stage 1 is measured by the change amount calculation unit 611 and the integration processing unit 612. It should be noted that these functional blocks may be realized in hardware as a result of dedicated circuitry taking part or all of the functions.

  The storage unit 62 mainly includes a ROM, a RAM, a hard disk, and the like, and stores programs read by the CPU 61 and various data. Note that the storage unit 62 may include a recording medium and a reading device thereof, and the CPU 61 may read a program or data recorded on the recording medium. Various data corresponds to measurement results D1, D2, difference result D3, integration result D4, and the like.

  The display unit 63 corresponds to a general CRT monitor or a liquid crystal display, and displays various data to the operator. The input unit 64 includes various buttons, keys, a mouse, a touch panel, and the like, and is operated by an operator to input instructions to the measurement apparatus 100.

  The above is the description of the configuration and functions of the measuring apparatus 100 in the present embodiment. Next, a method for measuring the straightness of the moving stage 1 using the measuring apparatus 100 will be described.

<1.2. Stage 1 straightness measurement method>
FIG. 9 is a schematic flowchart of a method for measuring the straightness of the stage 1 moving in the (+ Y) direction using the measuring apparatus 100. First, the operator fixes (sucks and holds) the pattern body 2 to a predetermined position (for example, the first position POS1 shown in FIG. 4) on the placement surface 10, and performs each imaging by the operations of the line camera 3 and the moving mechanism 4. The position in the X-axis direction of the pattern 21 at the point is measured (step S1).

  FIG. 10 is a flowchart showing details of the measurement operation. First, as shown in FIG. 5, the operator installs T-shaped pins P1 in all of the pin insertion holes H1 to H3, brings the pattern body 2 into contact with each pin, and places the pattern body 2 in the first position. Deploy. Then, after the pattern body 2 is placed, the control unit 6 operates the vacuum pump to suck and fix the pattern body 2 to the placement surface 10 (step S11).

  Then, the control unit 6 moves the stage 1 to a predetermined measurement start point by the operation of the moving mechanism 4. This measurement start point is a position at which the line sensor 31 is disposed at the imaging position (Y1) on the stage 1 (the (+ X) side end of the pattern 21) when viewed from the stage 1 (see FIG. 6). . From this point, by moving the stage 1 in the (+ Y) direction, the line camera 3 is moved in the (−Y) direction relative to the stage 1, and at each of the imaging points (Y1) to (Ym). The center position of the pattern 21 in the X-axis direction is calculated (step S12).

  Further, the control unit 6 determines whether or not a specific imaging point has been reached based on the position detection result of the stage 1 by the stage position detection mechanism 5. Based on the captured image ID acquired by the line camera 3 when it is determined that the specific imaging point has been reached, the position information of the center position of the pattern 21 calculated by the center position calculation unit 610 is the specific information. This is a measurement result of the position of the pattern 21 at the imaging point.

  In step S12, when the measurement at all the imaging points is completed, the control unit 6 stops the operation of the vacuum pump and releases the suction state of the pattern body 2. Then, the operator removes the T-shaped pin P1 inserted in the pin insertion holes H1 and H2, attaches the I-shaped pin P2, and brings the end of the pattern body 2 into contact with each pin. The body 2 is placed at the second position POS2. Furthermore, the control unit 6 operates the vacuum pump again to suck and fix the pattern body 2 on the placement surface 10 (step S13).

  When the suction holding is completed, the control unit 6 operates the moving mechanism 4 and the line camera 3 to move the stage 1 in the (+ Y) direction and move the imaging point (Y1 on the stage 1 as in step S12). ) To (Ym), the pattern 21 is imaged, and the center position of the pattern 21 at each imaging point is measured from the obtained captured image ID (step S14).

  In the present embodiment, the imaging interval Dy is made to coincide with the shift amount L3 (= (L1−L2) / 2) between the first position POS1 and the second position POS2 of the pattern body 2.

  The above steps S11 to S14 are a detailed flow of the measurement operation (step S1, FIG. 9). The measurement result D1 obtained in steps S11 and S12 and the measurement result D2 obtained in steps S13 and S14 are stored in the storage unit 62, respectively.

  Note that the execution order of steps S11 and S12 and steps S13 and S14 is not limited to this. For example, the execution order may be changed as appropriate, for example, steps S13 and S14 are executed first.

  Returning to FIG. 9 again, when the measurement operation is completed, the control unit 6 performs difference calculation processing by the change amount calculation unit 611 based on the measurement results D1 and D2 (step S2). Thereby, when the stage 1 is moved in the (+ Y) direction, the change amount of the movement error in the X-axis direction of the stage 1 between the respective imaging points is calculated. Further, after performing the difference calculation process, the integration processing unit 612 performs the integration process on the difference result D3 (step S3). Thereby, the displacement amount of the height position in each imaging point of the mounting surface 10 is calculated. Details of steps S2 and S3 will be described with reference to FIG.

  FIG. 11 is a diagram illustrating an example of the integration result D4 based on the measurement results D1 and D2. As described above, the center position of the pattern 21 calculated by the center position calculation unit 610 depends on the movement error (straightness) from the predetermined reference in the X axis direction of the moving stage 1 with respect to the Y axis of the pattern 21 itself. The amount of displacement at the center position in the X-axis direction is taken into account.

  Therefore, in the following, the movement error of the stage 1 in the X-axis direction at the i-th imaging point (Yi) is A (i). Further, the displacement amount of the center position of the pattern 21 itself at the imaging point (Yi) when the pattern body 2 is placed at the first position POS1 will be described as B (i).

  As shown in FIG. 11, the measurement result D1 at the imaging point (Yi) when the pattern body 2 is placed at the first position POS1 is expressed as A (i) + B (i) + α by the above setting. . On the other hand, the measurement result D2 at the imaging point (Yi) when the pattern body 2 is placed at the second position POS2 is (L1-L2) / 2 from the first position POS1 to the (+ Y) direction. Since it is shifted by (= imaging interval Dy), it is expressed as A (i) + B (i + 1) + α. Although the description is omitted in FIG. 11, the value α here is a value that changes depending on the method of reference when calculating the center position of the pattern 21 during stage movement, and is a value that is common to all imaging points. is there.

  The change amount calculation unit 611 is, for example, a measurement result D1 (= A (i) + B (i) + α) at the imaging point (Yi), an imaging point adjacent to the imaging point (Yi), and one of the imaging directions. The difference from the measurement result D2 (= A (i) + B (i-1) + α) at the imaging point (Y (i-1)) on the near side (that is, (+ Y) direction on the stage 1) is taken. Thus, the displacement amount B (i) and the value α at the center position of the pattern 21 itself are canceled out. Thereby, the change amount (= A (i) −A (i−1)) of the movement error between the imaging point (Y (i−1)) and the imaging point (Yi) of the stage 1 is calculated.

  In the present embodiment, by performing such difference calculation processing, the amount of change in the position in the X-axis direction of the stage 1 that moves in the (+ Y) direction between adjacent imaging points is calculated. Then, by performing the same difference calculation process based on the measurement results D1 and D2 at all the imaging points, the amount of change in the position of the moving stage 1 in the X-axis direction between the respective imaging points is calculated.

  Further, the integration processing unit 612 calculates the amount of displacement (movement error) in the X-axis direction of the stage 1 at each imaging point by performing integration (cumulative addition) based on the difference value calculated by the change amount calculation unit 611. To do. That is, for the movement error at the imaging point (Yi), the amount of change (difference value between the measurement results D1 and D2) between the imaging points from the imaging point (Y1) as the imaging start position to the imaging point (Yi) is integrated. It is calculated by doing.

  For example, the movement error in the X-axis direction of the stage 1 at the third imaging point (Y3) is based on the center position (= A (1)) in the X-axis direction of the pattern 21 at the imaging point (Y1). At this time, the amount of change in the position of the stage 1 between the first and second imaging points (Y1) and (Y2) (= A (2) -A (1)) and the second and third imaging points ( It is calculated as an integrated value (= A (3) −A (1)) with the amount of change in the position of the stage 1 (= A (3) −A (2)) between Y2) and (Y3). By performing such integration processing, the amount of displacement of the stage 1 in the X-axis direction at each imaging point is calculated.

  Returning to FIG. 11 again, when the integration process is completed, the integration processing unit 612 stores the integration result D4 in the storage unit 62. The data stored in the storage unit 62 is appropriately processed and moved, for example, when evaluating the straightness of the stage 1 moving in the Y-axis direction with respect to the X-axis direction or in a specific apparatus (for example, an exposure apparatus). This is used when correcting the processing position (for example, exposure position) according to the straightness of the stage 1 in the middle.

  As described above, in this embodiment, when measuring the movement error in the X-axis direction of the stage 1 moving in the Y-axis direction, the measurement result D1 of the pattern 21 center position and the pattern 21 are shifted in the Y-axis direction. By taking the difference from the measurement result D2 in the measured state, the amount of displacement in the X-axis direction at each position of the pattern 21 itself is canceled. Therefore, since it is possible to suppress the demand for the processing accuracy of the shape of the pattern 21 itself, it is possible to easily and accurately measure the straightness of the stage 1 moving in the Y-axis direction while suppressing the processing cost of the pattern body 2.

  In the present embodiment, the X axis direction orthogonal to the moving direction of the stage 1 does not require a position detection mechanism (for example, a laser length measuring device and a corner cube) for precise detection. Cost can be reduced.

  In the present embodiment, the direction of deviation between the first position POS1 and the second position POS2 is parallel to the moving direction of the stage 1. Further, the shift amount L3 (= (L1−L2) / 2) between the first position POS1 and the second position POS2 and the imaging interval Dy are made to coincide with each other. Thereby, since one-to-one correspondence can be performed when the difference calculation process is performed between the measurement result D1 and the measurement result D2, the measurement results D1 and D2 can be used efficiently, and the time required for the measurement Can be shortened.

<2. Modification>
Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made.

  For example, in the above embodiment, the stage 1 is moved and measured in the (+ Y) direction. However, the stage 1 may be moved and moved in the (−Y) direction. In this case, the measurement may be started from the imaging point (Ym).

  Moreover, in the said embodiment, although the shape of the pattern 21 when mounting the pattern body 2 on the mounting surface 10 was made into the substantially straight line, as above-mentioned, the displacement amount of the shape of pattern 21 itself is a difference calculation. Since the pattern 21 is canceled out by the processing, the pattern 21 may have any shape (including a curve and a broken line). However, in order to efficiently measure the straightness, the size of the pattern 21 may be a shape that falls within the range of the imaging region in the X-axis direction of the line camera 3 (specifically, the line sensor 31). preferable.

  In the above embodiment, the center position in the X-axis direction of the pattern 21 at each imaging point is measured. For example, the position of the edge portion on the (+ X) side or (−X) side of the pattern 21 is measured. You may comprise so that it may calculate, or you may comprise so that the arbitrary positions between each edge may be calculated.

  Moreover, in the said embodiment, although the position of the said pattern 21 is measured using the pattern body 2 in which the linear pattern 21 was formed in the upper surface, for example, the position of the pattern body 2 itself is measured. By doing so, the straightness of the moving stage 1 may be measured.

  In the above-described embodiment, the line camera 3 has been described as acquiring a captured image ID as a multi-valued image. However, the present invention is not limited to this and may be configured to acquire an image as a binary image.

  In the above-described embodiment, the shift amount L3 (= (L1−L2) / 2) between the first position POS1 and the second position POS2 and the imaging interval Dy in the Y-axis direction are matched. It is not limited. However, from the viewpoint of efficiently performing the measurement, it is desirable that the amount of deviation is a natural number times the imaging interval Dy. In addition, the imaging interval Dy at each imaging point is not limited to a fixed one, but from the viewpoint of efficiently using the measurement result, it should be set at regular intervals as in the present embodiment. Is desirable.

  In the above embodiment, the pattern body 2 (pattern 21) is shifted between the first position POS1 and the second direction so as to follow the moving direction of the stage 1, but the shifting direction is limited to this. It is not a thing. That is, the second position POS2 may be shifted from the first position POS1 along at least the moving direction of the stage 1, and may be shifted by a predetermined length in the X-axis direction, for example. In this case, for example, the measurement apparatus 100 may be configured to generate data in which a predetermined length in the X-axis direction is excluded from the measurement result D2 at the stage of obtaining the measurement result D2.

  In the above embodiment, the method for measuring the straightness in the X-axis direction of the stage 1 moving in the Y-axis direction has been described. However, the present invention is also effective when measuring the straightness in the Z-axis direction. is there. This point will be described with reference to FIG.

  FIG. 12 is a perspective view showing an outline of a measuring apparatus 100a according to a modification. In addition, about the structure similar to the said embodiment, the same code | symbol is attached | subjected suitably and description is abbreviate | omitted. In this measuring apparatus 100a, the pattern body 2a is fixed to the side surface of the stage 1 in the X-axis direction (here, -X side). Although not described in detail, the measuring apparatus 100a is configured to be able to fix the fixed position of the pattern body 2 to a position shifted from the position shown in FIG. 1 by the imaging interval Dy along the Y-axis direction.

  The line camera 3a is provided with a line sensor (not shown) extending in the Z-axis direction, and images the pattern 21a on the pattern body 2a when the stage 1 is moved in the Y-axis direction.

  Here, a method for measuring the movement error (straightness) of the stage 1 in the Z-axis direction when the stage 1 is moved in the Y-axis direction by the measuring apparatus 100a will be described.

  First, as in the above embodiment, the measurement of the center position of the pattern 21a in the Z-axis direction when the stage 1 is moved in the Y-axis direction, and the pattern 21a with respect to the stage 1 along the Y-axis direction. In the shifted state, the center position in the Z-axis direction of the pattern 21a when the stage 1 is moved in the Y-axis direction is measured. Thereby, two measurement results are acquired.

  Similarly to the above embodiment, the difference calculation process based on the two measurement results is performed so as to cancel out the displacement amount in the Z-axis direction of the pattern 21a itself. Further, by performing these integration processes (accumulation addition of differences), the displacement amount (movement error, straightness in the Z-axis direction) of the stage 1 moving in the Y-axis direction from the predetermined reference in the Z-axis direction for each imaging point. Degree) is calculated.

  Even in this case, the straightness in the Z-axis direction of the stage 1 moving in the Y-axis direction can be easily and accurately measured regardless of the shape of the pattern 21a, as in the above-described embodiment. The above is the description of the method for measuring the straightness of the moving stage 1 in the Z-axis direction.

  In addition, each structure demonstrated by the said embodiment and modification can be suitably combined unless it mutually contradicts.

It is a perspective view which shows the outline of the measuring apparatus in embodiment which concerns on this invention. It is sectional drawing of the stage which shows the state which inserted the T-shaped pin in the pin insertion hole. It is sectional drawing of the stage which shows the state which inserted the I-shaped pin in the pin insertion hole. It is a top view of the stage which shows the state which has arrange | positioned the pattern body in the 1st position. It is a top view of the stage which shows the state which has arrange | positioned the pattern body in the 2nd position. It is a figure for demonstrating the imaging position of the pattern by a line camera. It is a block diagram which shows the connection of a control part and each structure of a measuring device. It is a figure for demonstrating the procedure which calculates | requires the center position of the X-axis direction of a pattern based on a captured image. It is a rough flowchart of the straightness measurement method of the stage which moves to a (+ Y) direction using a measuring device. It is a flowchart which shows the detail about measurement operation | movement. It is a figure which shows an example of an integration result based on a measurement result. It is a perspective view which shows the outline of the measuring apparatus which concerns on a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100,100a Measuring apparatus 1 Stage 2, 2a Pattern body 21, 21a Pattern 3, 3a Line camera 31 Line sensor 4 Moving mechanism 5 Stage position detection mechanism 6 Control part 61 CPU
610 Center position calculation unit 611 Change amount calculation unit 612 Integration processing unit D1, D2 Measurement result D3 Difference result D4 Integration result H1-H3 Pin insertion hole I1 Captured image L1, L2 Diameter L3 Deviation amount Ly Imaging interval P1 T-shaped pin P2 I-shaped pin POS1 1st position POS2 2nd position

Claims (4)

A straightness measurement method for measuring the straightness of the support when the support that supports the object to be processed is moved along the first direction,
A first fixing step of fixing a measurement reference object at a first position of the support;
A second reference that is substantially orthogonal to the first direction of the measurement reference object while moving the support on which the measurement reference object is fixed at the first position in the first fixing step along the first direction. A first measuring step for measuring a displacement amount in a direction;
A second fixing step of fixing the measurement reference object to a second position of the support that is shifted from the first position by a predetermined length along at least the first direction;
The displacement of the measurement reference object in the second direction is measured while moving the support body in which the measurement reference object is fixed at the second position in the second fixing step along the first direction. A second measuring step,
By taking the difference of the displacement amount of the measurement reference object measured in the first measurement step and the second measurement step, the displacement amount of the measurement reference object itself in the second direction is offset, and the support A displacement amount calculating step of calculating a displacement amount in the second direction of the support when the body is moved along the first direction;
A straightness measurement method comprising: The straightness measurement method according to claim 1,
The measurement standard is
Straightness measurement comprising a pattern extending at least in the first direction when the measurement reference object is fixed at the first position and the second position in the first fixing step and the second fixing step. Method. The straightness measurement method according to claim 2,
In the first measurement step and the second measurement step, the displacement amount of the center position in the second direction of the pattern is measured, respectively. A straightness measuring device that measures the straightness of the support when the support that supports the object to be processed is moved along the first direction,
Moving means for moving the support in the first direction;
A measurement reference fixed to the support;
Displacement amount measuring means for measuring a displacement amount of the measurement reference object in a second direction substantially orthogonal to the first direction when the support to which the measurement reference object is fixed is moved in the first direction. When,
First position fixing means for fixing the measurement reference object to a first position of the support;
Second position fixing means for fixing the measurement reference object to a second position shifted by a predetermined length along the first direction from the first position of the support;
The difference between the measurement result of the displacement of the predetermined measurement reference object fixed at the first position and the measurement result of the displacement of the measurement reference object fixed at the second position by the displacement measurement means. The amount of displacement of the measurement reference object itself in the second direction is canceled out, and the amount of displacement of the support in the second direction when the support is moved along the first direction. A displacement amount calculating means for calculating;
A straightness measuring apparatus comprising:

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