JP2006052971A - Critical dimension measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately and simultaneously measure a plurality of patterns even when an object to be measured is arranged at an angle or patterns on the object to be measured is very slightly displaced from a specified position. <P>SOLUTION: A plurality of detecting parts 26 and 28 are arranged in such a way as to asynchronously move along an X-axis frame 18. The detecting parts 26 and 28 as a whole are arranged in such a way as to move along a Y-axis frame 20. Each of the detecting parts 26 and 28 is arranged in such a way as to asynchronously move along a Y-axis direction within a prescribed range. When a flat panel 46 is arranged in such a way as not to be in parallel with X-Y coordinate axes and arranged at an angle to the Y-axis or when patterns of a liquid crystal monitor 48 are displaced from registered patterns, the detecting parts 26 and 28 are independently moved along the Y-axis direction to correct positional displacements according to the inclination and pattern displacements of the flat panel 46 to accurately and simultaneously measure a plurality of patterns on the liquid crystal monitor 48 and shorten tact time. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a micro dimension measuring machine configured to take an image of an object to be measured as a subject and process an image obtained by the imaging to measure the minute dimension of the object to be measured.

  For measuring the minute dimensions of the object to be measured, for example, the space facing each liquid crystal monitor on the flat panel on which the liquid crystal monitor is formed is used as a moving space, and the detector is moved in a three-dimensional direction to There is one in which the line width of the formed pattern is measured by a detector. This type of micro-dimension measuring machine is formed on each liquid crystal monitor by mounting an imaging camera or the like on the detector, imaging each liquid crystal monitor with the imaging camera, and processing the image obtained by this imaging. The line width of the pattern can be measured.

  However, in a configuration in which a plurality of liquid crystal monitors are measured with a single detector, it takes time to move the detector to the position of each liquid crystal monitor, and the measurement time for the flat panel cannot be shortened. In order to shorten the measurement time (tact time) of a flat panel on which a plurality of liquid crystal monitors are formed, it is conceivable to employ a configuration in which a plurality of detectors are prepared and each detector is moved to each liquid crystal monitor simultaneously. .

  For example, a flat panel is arranged in parallel to the XY coordinates (machine coordinates) of the measuring machine, and a plurality of detectors are slidably arranged on an X-axis frame constituting the X axis. Each detector can be moved to the position of each liquid crystal monitor by moving the arranged X-axis frame along the Y-axis direction by the Y-axis drive unit.

  However, in a configuration in which a plurality of detectors are slidably arranged on the X-axis frame and the X-axis frame on which the plurality of detectors are arranged is moved along the Y-axis direction, each detector is moved along the X-axis direction. Can be moved individually, but not individually in the Y direction. For this reason, when the flat panel is not arranged parallel to the XY coordinates of the measuring machine, for example, when arranged in a state inclined with respect to the Y axis, the detectors are simultaneously moved along the Y axis direction. Later, even if each detector is moved individually along the X-axis direction, one detector can be positioned at a specified measurement position, but the other detector can be positioned at a specified measurement position. It is impossible to measure a plurality of patterns simultaneously by each detector.

  Even if the flat panel can be arranged parallel to the XY coordinates, if the pattern at any measurement site is slightly shifted from the registered pattern, each detector is moved to the measurement site. Measuring the pattern cannot measure the exact dimensions of the pattern. That is, when the pattern is slightly deviated from the registered pattern, a plurality of patterns cannot be measured accurately unless the position of each detector is corrected according to the deviation.

  The present invention has been made in view of the above-described conventional problems. The object of the present invention is that the object to be measured is not arranged parallel to the machine coordinates of the measuring machine, and the object to be measured is arranged at an inclination. Or, even if the pattern on the object to be measured is slightly deviated from the specified position, a plurality of patterns can be measured accurately and simultaneously.

  In order to achieve the above object, in the micro-dimension measuring machine according to claim 1, a plurality of detection units that respectively capture a plurality of patterns on the object to be measured, and an image captured by the plurality of detection units are processed. An image processing unit that calculates minute dimensions related to the plurality of patterns, and a space that faces the measurement region of the object to be measured is at least a movement space, and the detection units are arranged in a three-dimensional direction in the movement space. A drive unit that moves the main drive unit that moves the whole of the plurality of detection units along a one-dimensional direction of the three dimensions, and at least a two-dimensional direction of the three dimensions. And an auxiliary driving unit that moves each of the plurality of detection units asynchronously.

  (Operation) When a plurality of patterns on the object to be measured are imaged by each detection unit, and an image obtained by this imaging is processed to measure a minute dimension related to each pattern, the entire plurality of detection units are arranged in a one-dimensional direction, for example, Since the plurality of detectors are moved along the Y-axis direction and are moved asynchronously along at least two-dimensional directions, for example, the X-axis direction and the Y-axis direction, the object to be measured is the machine of the measuring machine. The object to be measured is not arranged in parallel to the coordinates, for example, the XY coordinates, and the object to be measured is disposed to be inclined with respect to the Y axis, or the position of the pattern on the object to be measured is slightly deviated from the specified position. However, by moving each detection unit asynchronously along at least the two-dimensional direction, the position of each detection unit can be finely adjusted, and multiple patterns can be measured accurately and simultaneously. It can be, it is possible to shorten the tact time. In addition, a plurality of measurement points can be measured at the same time, and the tact time can be shortened.

  According to a second aspect of the present invention, in the micro-dimension measuring machine according to the first aspect, the auxiliary driving unit sets the X, Y, and Z directions as a three-dimensional direction and the plurality of detection units asynchronously along the X direction. A plurality of X-direction auxiliary drive units to be moved, a plurality of Y-direction auxiliary drive units to move the plurality of detection units asynchronously along the Y direction, and a plurality of detection units to the Z direction, respectively. A plurality of Z-direction auxiliary driving units that are moved asynchronously are provided.

  (Operation) After moving the entire plurality of detection units to the vicinity of each pattern, each detection unit is moved asynchronously along the X direction, the Y direction, or the Z direction, thereby finely adjusting the position of each detection unit individually. can do.

  According to a third aspect of the present invention, in the micro-dimension measuring machine according to the second aspect, at least one of the plurality of X-direction auxiliary drive units, the plurality of Y-direction auxiliary drive units, or the plurality of Z-direction auxiliary drive units. Any one of them is composed of a linear motor including a magnet arranged along a designated direction among the X, Y, and Z directions and a coil arranged in each of the detection units.

  (Operation) By configuring the auxiliary drive unit with a linear motor having a magnet and a coil, each detection unit can be moved asynchronously even if multiple detection units are arranged on the same axis. Simplification can be achieved.

  As is clear from the above description, the micro dimension measuring machine according to claim 1 can reduce the tact time.

  According to the second aspect, the position of each detection unit can be finely adjusted individually.

  According to the third aspect, the configuration can be simplified.

  Next, embodiments of the present invention will be described based on examples. FIG. 1 is a perspective view of a micro-dimension measuring machine showing an embodiment of the present invention, and FIG. 2 is a perspective view of the micro-dimension measuring machine showing an embodiment of the present invention when the detection unit is omitted. FIG. 3 is a plan view of a flat panel, FIG. 4 is an enlarged plan view of a measurement pattern, FIG. 5 is a configuration diagram of a fully closed loop control system, and FIG. 6 is a view when the flat panel is tilted. It is a top view which shows the state of.

  In these drawings, a micro-dimension measuring machine 16 is a three-dimensional measuring machine, which is an X-axis frame 18 constituting the X axis of XY coordinates (machine coordinates) and a pair of Y-axis frames constituting the Y axis. 20, a base 22, a measurement table 24 fixed on the base 22, a plurality of detection units 26, 28 arranged so as to be asynchronously movable on the X-axis frame 18, and each detection unit 26, 28. An X-axis drive unit 30 for moving along the X-axis direction, a Y-axis drive unit 32 for moving the detection units 26 and 28 along the Y-axis direction, and the detection units 26 and 28 in the Z-axis direction A Z-axis drive unit 34 for movement along the PC, a personal computer (hereinafter referred to as a PC) 36 for performing calculations for controlling the drive of each drive unit, and a display for displaying the processing results of the PC 36, etc. Various information on the device 38 and the PC 36 Keyboard 40 for force, is configured to include a like control box 42 to indicate a driving direction of the drive units.

  Sliding portions (not shown) are formed at both axial ends of the X-axis frame 18, and each sliding portion is configured to be slidable along each Y-axis frame 20. The X-axis frame 18 can be moved along the Y-axis direction by driving the Y-axis drive unit 32. The Y-axis drive unit 32 includes a plurality of Y-axis linear motor magnets 32a and a Y-axis linear. It is comprised with the linear motor provided with the coil 32b for motors. When the coil 32b of the linear motor is energized and the energization amount and energization direction to the coil 32b are controlled by the PC 36, the X-axis frame 18 moves along the Y-axis direction (Y-axis frame 20). . That is, by driving the Y-axis drive unit 32, the entire detection units 26 and 28 can move along the Y-axis direction as the X-axis frame 18 moves. In this case, the Y-axis drive unit 32 constitutes a main drive unit that moves the detection units 26 and 28 along the Y-axis direction.

  The X-axis frame 18 is provided with an X-axis drive unit 30 for moving the detection units 26 and 28 asynchronously along the X-axis direction (X-axis frame 18). The X-axis drive unit 30 includes a plurality of X-axis linear motor magnets 30 a disposed along the X-axis frame 18 and X-axis linear motor coils 30 b mounted on the detection units 26 and 28. Configured. By controlling the energization amount and energization direction for each coil 30b by the PC 36, the detection units 26 and 28 can be moved asynchronously (independently) along the X-axis direction. In this case, the X-axis drive unit 30 configured by a linear motor constitutes an X-direction auxiliary drive unit that moves the detection units 26 and 28 asynchronously along the X-axis direction.

  The base 22 on which the X-axis frame 18 and the Y-axis frame 20 are fixed is supported by a plurality of frame bodies 44 fixed on the base. A measurement table 24 constituting XY coordinates serving as machine coordinates is arranged. Both ends of the measurement table 24 are supported by table frames 24a, and a flat panel 46 as an object to be measured is mounted on the measurement table 24 as shown in FIG. A plurality of liquid crystal monitors 48 as measurement objects are formed on the flat panel 46 formed in a substantially rectangular shape. Alignment marks M1 and M2 are formed on the upper and lower portions of the flat panel 46 on the left end side. Measurement points (management points) P1 to P4 are set on each liquid crystal monitor 48, and patterns PT1, PT2,... Constituting a driving circuit and the like are formed as shown in FIG.

  The detection units 26 and 28 are arranged so as to be movable along the three-dimensional direction in at least a movement area, which is a space facing the liquid crystal monitor 48 arranged in the measurement area of the flat panel 46. The units 26 and 28 include a detection unit main body 50. An objective lens 54 and a CCD camera 56 are housed in the lens barrel 52 of each detection unit main body 50 as an imaging means for imaging a pattern on the liquid crystal monitor 48 using the liquid crystal monitor 48 on the flat panel 46 as a subject. ing. The objective lens 54 and the CCD camera 56 have a function as an electron microscope, enlarge the pattern on the liquid crystal monitor 48 and take an image, and transfer a signal related to the taken image to the PC 36 via a cable (not shown). It has become. In addition, each lens barrel 52 is respectively connected to a Z-axis servo motor 58 as an auxiliary drive unit for Z direction for moving the image pickup means along the Z-axis direction according to a control signal from the PC 36 for focusing of the image pickup means. It is connected. In this case, one Z-axis servo motor 58 functions as a Z1-axis servo motor, the other Z-axis servo motor 58 functions as a Z2-axis servo motor, and the objective lens 54 and the CCD camera 56 in one lens barrel 52 are connected. It can reciprocate along the Z1 axis, and the objective lens 54 and the CCD camera 56 in the other lens barrel 52 can reciprocate along the Z2 axis.

  Further, in each detection unit main body 50, in response to a control signal from the PC 36, a Y-axis servomotor 60 as an auxiliary drive unit for Y direction that moves each detection unit 26, 28 asynchronously along the Y-axis direction. Is provided. One Y-axis servomotor 60 is a Y1S servomotor, and can reciprocate one detection unit 26 along an auxiliary Y-axis (Y1S-axis) parallel to the Y-axis frame 20, while the other Y-axis As the Y2S servomotor, the servomotor 60 can reciprocate the other detection unit 28 along the auxiliary Y axis (Y2S axis) parallel to the Y axis frame 20.

  Here, in order to determine the positions of the detection units 26 and 28 in the X-axis direction with high accuracy, the X-axis drive unit 30 has a full closed loop control system as shown in FIG. It is configured.

  Specifically, a plurality of magnets 30a are arranged in parallel with the X axis (X axis frame 18), and a linear guide 62 and glass for guiding the movement of each detection unit main body 50 in parallel with the X axis. A scale 64 is arranged. Each detection unit main body 50 is equipped with a position sensor (linear sensor) 66, and each position sensor 66 detects the scale of the glass scale 64 and outputs a detection signal to the scale counter 68. The scale counter 68 counts the number of scales on the glass scale (linear scale) 64 in response to the detection signal of the position sensor 66 and outputs the count value to the monitor driver 70. The monitor driver 70 outputs position information of each detection unit main body 50 to the linear motor and the PC 36, and the PC 36 can control an energization amount and an energization direction to the coil 30b on each detection unit main body 50 based on the position information. In addition, the positioning of each detection unit main body 50 in the X-axis direction can be controlled with high accuracy.

  Also, in the Y-axis drive unit 32, similarly to the X-axis drive unit 30, the position sensor 66a and the like are used to form a full-closed loop control system, thereby positioning the detection units 26 and 28 in the Y-axis direction. It can be performed with high accuracy.

  When the pattern of the liquid crystal monitor 48 formed on the flat panel 46 is measured using the micro-dimension measuring device 16 having the above-described configuration, the flat panel 46 disposed on the measurement table 24 is measured as shown in FIG. In order to detect the positions of the alignment marks M1 and M2, for example, the detection unit 26 is arranged at a position corresponding to the alignment marks M1 and M2, and the X-axis frame 18 is moved along the Y-axis direction. Then, the alignment marks M1 and M2 are sequentially imaged, and the image obtained by the imaging is processed by the PC 36 to determine whether or not the flat panel 46 is arranged in parallel to the XY coordinates. When it is determined that the flat panel 46 is arranged in parallel to the XY coordinates, the X-axis frame 18 is placed in the Y-axis with the detection units 26 and 28 being placed at specified positions on the X-axis frame 18, respectively. First, it is positioned on a liquid crystal monitor 48 disposed on the upper left side of the flat panel 46. At this time, the detectors 26 and 28 are moved along the X-axis frame 18 to position the detectors 26 and 28 at positions corresponding to the measurement points P1 and P2. Further, focusing is performed by moving the detection units 26 and 28 in the Z-axis direction by driving the Z-axis servomotor 58, respectively. When this focusing is performed, each measurement point P1, P2 is imaged by the CCD camera 56, and an image obtained by this imaging is processed by the PC. In this case, pattern matching between a pattern obtained by measurement and a registered pattern registered in advance is performed, and it is determined whether or not there is a deviation between the two. When there is no deviation between the two, the images picked up by the detectors 26 and 28 are processed, and the line widths of the patterns PT1 and PT2 at the measurement points P1 and P2 are measured as shown in FIG. In this case, the PC 36 functions as an image processing unit that processes an image captured by the CCD camera 56 and calculates minute dimensions related to a plurality of patterns. When the PC 36 performs these processes for the measurement points P1, P2, P3, and P4 on each liquid crystal monitor 48 and measures the measurement points P1 to P4, the pattern PT1 at the measurement points P1, P2 and the measurement points P3, P4. The tact time can be shortened by simultaneously measuring the minute dimensions of PT2 by the detection units 26 and 28, respectively.

  When there is a slight deviation between the two in the pattern matching, the detection unit 24 or the detection unit 26 that has detected the deviation among the detection units 26 and 28 is driven by the Y-axis servomotor 60 and the Y-axis (auxiliary Y-axis) ) Can be corrected by moving in the direction.

  On the other hand, as shown in FIG. 6, due to the measurement of the alignment marks M1 and M2 on the flat panel 46, the flat panel 46 is not arranged in parallel to the XY coordinates of the micro dimension measuring device 16, and the Y axis (Y When it is determined that the Y-axis servo motor 60 is disposed in an inclined state with respect to the axis frame 20), each Y-axis servo motor 60 is driven based on the inclination of the flat panel 46 with respect to the Y-axis direction in order to correct the inclination with respect to the Y-axis. Then, the offset amount in the Y-axis direction of each of the detection units 26 and 28 is corrected. In this case, the detection unit 28 is positioned away from the detection unit 26 with respect to the origin of the XY coordinates, and thus is positioned at a position slightly moved in the Y-axis direction relative to the detection unit 26. The origin of the XY coordinates is provided on the lower left side of FIG. 1 for convenience, but may be the XY movement center.

  After the offset amounts for the detection units 26 and 28 are corrected, the detection units 26 and 28 are moved along the Y-axis direction together with the X-axis frame 18 by driving the linear motor, and the measurement points P1 and Positioned above P2. At this time, the driving of the Z-axis servomotor 58 causes the detection unit 28 to move in the Z-axis direction to perform focusing. The origins of the detection units 26 and 28 in the Y-axis direction are the centers of forward and backward movement of the detection units when the detection units 26 and 28 are translated along the X-axis, respectively. Further, as long as the detection units 26 and 28 are parallel to the X axis, any position of the movement may be used as the origin. Thereafter, when the CCD 56 of the detectors 26 and 28 performs imaging for each of the measurement points P1 and P2, images associated with the imaging are processed by the PC 36, and pattern matching between the detected pattern and the registered pattern is performed. Done. When it is determined by this pattern matching that there is a slight deviation between the two, a process for correcting the deviation is performed on the detection unit 26 or the detection unit 28 that has detected the deviation. That is, the Y-axis servomotor 60 is driven according to the control signal for correcting the deviation, and the deviation is corrected by the movement of the detection unit 26 or the detection unit 28 in the Y-axis (auxiliary Y-axis) direction. In this case, coordinate conversion is performed from the machine coordinate system using the alignment marks M1 and M2 as a reference.

  Thereafter, the measurement points P1 and P2 are imaged again by the detection units 26 and 28, and the image obtained by the imaging is processed by the PC 36, and the fine line widths of the patterns PT1 and PT2 on the measurement points P1 and P2 are processed. Measurements on (CD) and overlay (OL) are made. That is, processing for measuring the width and size of the pattern in micron order as minute dimensions is executed.

  After the measurement is completed, a process for returning the offset correction amount calculated by the pattern matching is performed, and the process proceeds to a process for measuring at the next measurement points P3 and P4. At the next measurement points P3 and P4, a process for correcting the offset amount in the Y-axis direction of each of the detection units 26 and 28 is performed based on the inclination of the flat panel 46, and the same process is repeated.

  As described above, according to the present embodiment, even if the flat panel 46 is inclined with respect to the Y-axis or the pattern of the liquid crystal monitor 48 is slightly shifted from the registered pattern, the detection units 26 and 28 can be connected to each other. Since the servo motor 60 can be asynchronously moved along the Y-axis (auxiliary Y-axis) direction by driving the servo motor 60, a plurality of patterns can be measured accurately and simultaneously, and the tact time can be shortened. Become.

  In the present embodiment, the detection units 26 and 28 can be moved asynchronously (independently) along the Z-axis by driving the Z-axis servo motor, so that focusing can be performed accurately, and a plurality of patterns can be obtained. More accurate measurement can be performed, and the tact time can be shortened.

  Further, since a linear motor is employed as the X-axis drive unit 30, the detection units 26 and 28 can be moved asynchronously over a wide range along the X-axis direction, and the configuration can be simplified.

It is a perspective view of the micro dimension measuring machine which shows one Example of this invention. It is a perspective view of the micro dimension measuring machine which shows one Example of this invention, Comprising: It is a perspective view which shows a state when a detection part is abbreviate | omitted. It is a top view of a flat panel. It is an enlarged plan view of a measurement pattern. It is a block diagram of a fully closed loop control system. It is a top view which shows a state when a flat panel inclines.

Explanation of symbols

16 Micro dimension measuring machine 18 X-axis frame 20 Y-axis frame 22 Base 24 Measurement table 26, 28 Detection unit 30 X-axis drive unit 32 Y-axis drive unit 34 Z-axis drive unit 36 PC
38 Display device 46 Flat panel 48 Liquid crystal monitor 50 Detection unit main body 56 CCD camera 58 Z-axis servo motor 60 Y-axis servo motor

Claims (3)

  A plurality of detection units that respectively capture a plurality of patterns on the object to be measured; an image processing unit that processes images captured by the plurality of detection units to calculate minute dimensions related to the plurality of patterns; and the object to be measured And a drive unit that moves the plurality of detection units along a three-dimensional direction in the movement space, wherein the drive unit is a one-dimensional one of the three dimensions. A main drive unit that moves the whole of the plurality of detection units along the direction, and an auxiliary drive unit that moves the plurality of detection units asynchronously along at least a two-dimensional direction of the three dimensions. A micro dimension measuring machine.   2. The micro dimension measuring machine according to claim 1, wherein the auxiliary driving unit is configured to move the plurality of detection units asynchronously along the X direction with the X, Y, and Z directions as a three-dimensional direction. Auxiliary drive units, a plurality of Y-direction auxiliary drive units that move the plurality of detection units asynchronously along the Y direction, and a plurality of movement units that move the plurality of detection units asynchronously along the Z direction, respectively. A micro-dimension measuring machine comprising an auxiliary driving unit for Z direction.   The minute dimension measuring machine according to claim 2, wherein at least one of the plurality of X-direction auxiliary drive units, the plurality of Y-direction auxiliary drive units, or the plurality of Z-direction auxiliary drive units is A micro dimension measuring machine comprising a linear motor provided with a magnet arranged along a designated direction in the X, Y, or Z directions and a coil arranged in each of the detection units.

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