JP4526988B2 - Minute height measuring method, minute height measuring apparatus and displacement unit used therefor - Google Patents

Description

  The present invention relates to a minute height measuring method for measuring a minute height of an object to be measured, and more specifically, a minute point for measuring the height of a measuring point at high speed by arbitrarily selecting a measuring point on the object to be measured. The present invention relates to a height measuring method, a minute height measuring device used therefor, and a displacement unit.

  A conventional minute height measuring apparatus of this type includes a laser oscillator as a light source, a laser beam deflecting unit for scanning the object to be measured with a laser beam, and an objective for condensing the scanned laser beam on the object to be measured. A lens, an optical system for branching reflected light from the object to be measured into two optical paths, and two optically different openings arranged near the imaging position of the reflected light in each branched optical path, Reflection obtained from an optical path provided with a small aperture, which includes a photodetector that detects reflected light that has passed through each aperture, and a processing unit that calculates the height of the object to be measured from the output signal of the photodetector. The measured value depending on the height of light is divided by the absolute value of the reflected light obtained from the optical path with a large aperture to obtain the height of the object to be measured, and this is calculated and stored in advance. Compared with the height conversion table, Has thus obtain a height corresponding to the (see Patent Document 1).

  However, since the above-mentioned minute height measuring apparatus scans the laser beam using a galvanometer mirror or the like, there is a limit to the scanning speed, and there is a problem of fluctuation phenomenon of the scanning beam.

  Therefore, in order to cope with such a problem, another device is configured to rotate integrally with a microlens disk in which a large number of microlenses are arranged in an array and the same rotation axis as the microlens disk. A pinhole disk in which a pinhole is formed at the focal position of each microlens of the microlens disk, and a light beam that has passed through the microlens of the microlens disk and the pinhole of the pinhole disk is condensed on the object to be measured. Between the microlens disk and the pinhole disk, an objective lens to be detected, a photodetector that is optically conjugate with the focal position of the objective lens and detects reflected / scattered light from the object to be measured. A light branching means for reflecting reflected / scattered light from the object to be measured to the photodetector side; and And a relay lens for condensing onto the detecting surface of the vessel (see Patent Document 2).

With the above-described configuration, the above-mentioned other apparatus condenses the laser beam as an individual light beam by each microlens arranged on the microlens disk, passes through the light branching means, and then is provided on each pinhole disk. It passes through the pinhole and is condensed on the object to be measured by the objective lens. Then, the reflected / scattered light generated from the object to be measured is condensed again on each pinhole of the pinhole disk by the objective lens, and after passing through each pinhole, reflected by the light branching means and reflected by the relay lens. The light is collected on the light detection means. As a result, the microlens disk and the pinhole disk can be rotated together to scan the laser beam at high speed over the entire observation area.
Japanese Patent Laid-Open No. 07-128025 JP 2004-340663 A

  However, since all of these conventional minute height measuring devices mechanically scan the light beam, the scanning speed of the light beam is limited and high-speed measurement is difficult. . In addition, since the entire observation area is scanned with a laser beam to measure the height of the object to be measured, it is not possible to select and measure any measurement point, and any point on the object to be measured. Could not be measured at high speed.

  In view of the above, the present invention addresses such a problem, and allows a measurement point on the measurement object to be arbitrarily selected so that the height of the measurement point can be measured at a high speed and a minute height used in the method. An object of the present invention is to provide a measuring device and a displacement unit.

  In order to achieve the above object, a minute height measuring method according to a first invention is arranged in an optically conjugate relationship with a focal position of an objective lens for condensing a light beam on an object to be measured. Among the micromirrors of the measurement point selection means in which the mirrors are arranged in a matrix, at least one micromirror is tilted to reflect the light beam from the light source toward the object to be measured, and reflected by the at least one micromirror. The light beam is condensed on the object to be measured by the objective lens, and the reflected and scattered light from the condensing point of the light beam condensed on the object to be measured is converted into the at least one micro of the measurement point selecting means. Detecting through the mirror, detecting the amount of displacement by displacing the object to be measured in the optical axis direction relative to the objective lens, and detecting through the at least one micromirror From the data of brightness and the detected amount of displacement of the light it is intended to obtain the displacement amount indicating the maximum brightness value as the height of the measurement point of the object to be measured.

  The measurement point selecting means arbitrarily selects and drives at least one of the plurality of micromirrors. Thereby, at least one micromirror is arbitrarily selected and driven among the plurality of micromirrors of the measurement point selection means.

  According to a second aspect of the present invention, there is provided a micro-height measuring apparatus comprising: a light source for irradiating a light beam; an objective lens for condensing the light beam from the light source on an object to be measured; And measuring point selection means in which a plurality of micromirrors individually arranged in a matrix are arranged so that the light beam from the light source is reflected in the direction of the object to be measured, and is collected on the object to be measured. A light detection means for detecting reflected and scattered light from the condensing point of the light beam through the measurement point selection means; and the object to be measured relative to the objective lens in the optical axis direction. Displacement means that detects and outputs the displacement amount, and each micromirror of the measurement point selection means is individually driven and controlled to control the displacement of the displacement means and detected by the light detection means Luminance of light and the change And control means for obtaining a displacement amount indicating the maximum luminance value from the input displacement amount of data from the means as the height of the measurement point of the object to be measured, but with a.

  With such a configuration, a light beam is emitted from a light source, and a plurality of micromirrors arranged in a matrix of measurement point selection means arranged in an optically conjugate relationship with the focal position of the objective lens are individually controlled by a control means. The light beam from the light source is tilted so as to be reflected in the direction of the object to be measured, and the light beam reflected by the micromirror by the objective lens is condensed on the object to be measured. The reflected and scattered light from the condensing point of the light beam collected on the object to be measured is detected through the measuring point selection means, the displacement of the displacement means is controlled by the control means, and the object to be measured is detected by the displacement means. Is displaced relative to the objective lens in the direction of the optical axis, the amount of displacement is detected and output, and the luminance of the light detected by the light detection means by the control means and the displacement input from the displacement means Maximum from quantity data A displacement amount indicating the degree value determined as the height of the measurement point of the object to be measured.

  According to a third aspect of the present invention, there is provided a micro-height measuring apparatus comprising: a light source that generates a light beam that irradiates an object to be measured; and a plurality of individually inclined light beams that reflect the light beam from the light source toward the object to be measured. Measurement point selection means in which micromirrors are arranged in a matrix, light detection means for detecting reflected and scattered light from the irradiation point of the light beam on the object to be measured via the measurement point selection means, and the measurement points Displacement means for displacing the selection means in the irradiation direction of the light beam to the object to be measured, and the displacement of the measurement point selection means and the luminance of the light detected by the light detection means while controlling the displacement of the displacement means A displacement meter unit having a displacement meter control circuit that outputs the data of the displacement meter in association with each other, an objective lens that focuses the light beam from the light source of the displacement meter unit on the object to be measured, and measurement of the displacement meter unit The micromirrors of the selection means are individually driven and controlled, and the displacement amount indicating the maximum luminance value is obtained as the height of the measurement point of the object to be measured from the displacement amount and light luminance data output from the displacement meter unit. And a control means.

  With such a configuration, a light beam is generated by the light source of the displacement meter unit, and a plurality of micromirrors arranged in a matrix of measurement point selection means are individually driven and controlled by the control means, so that the light beam from the light source is generated. Tilt so as to reflect in the direction of the object to be measured, the light beam reflected by the micromirror by the objective lens is condensed on the object to be measured, and the displacement of the displacement means is controlled by a displacement meter control circuit. Then, at least the measurement point selection means is displaced in the irradiation direction of the light beam on the object to be measured, and the reflected and scattered light from the irradiation point of the light beam on the object to be measured is detected by the light detection means via the measurement point selection means. The displacement meter control circuit outputs the displacement amount of the measurement point selection means and the light brightness data detected by the light detection means in association with each other, and the control means outputs the maximum brightness value based on the data. Obtaining a displacement amount indicating the height of the measurement point of the object to be measured.

  Further, the control means arbitrarily selects and drives at least one micromirror among the plurality of micromirrors of the measurement point selection means. Thereby, at least one micromirror is arbitrarily selected and driven among the plurality of micromirrors of the measurement point selection means by the control means.

  Further, the light detection means is disposed on the optical path between the light source and the measurement point selection means, and is reflected by the light branching means that branches the optical path from the measurement point selection means in two. Is received. Thereby, the light splitting means is arranged on the optical path between the light source and the measuring point selecting means and splits the optical path from the measuring point selecting means in two, and reflects the light from the measuring point selecting means. Is received by the light detection means.

  Furthermore, the light detection means is a photomultiplier tube or an image pickup device, or a combination of the two, which can be switched to enable light detection. As a result, the reflected and scattered light from the object to be measured is detected by a photomultiplier tube or an image sensor, or a combination of the two is switched to detect the reflected and scattered light from the object to be measured.

  The light source is a laser light source or a white light source, or a combination of the two can be switched for irradiation, or a combination of laser light sources having different wavelengths can be switched for irradiation. Thereby, the laser light source or the white light source is used for irradiation, or a combination of the two or a combination of laser light sources having different wavelengths is used for irradiation.

  According to a fourth aspect of the present invention, there is provided a displacement meter unit comprising: a light source that generates a light beam that irradiates an object to be measured; and a plurality of micromirrors that are individually tilted so that the light beam from the light source is reflected toward the object to be measured. Measurement point selection means arranged in a matrix, light detection means for detecting reflected and scattered light from the irradiation point of the light beam on the object to be measured via the measurement point selection means, and the measurement point selection means. Displacement means for displacing the object to be measured in the irradiation direction of the light beam, and controlling the displacement of the displacement means, the displacement amount of the measurement point selection means, and the luminance data of the light detected by the light detection means Is provided with a displacement meter control circuit that outputs in association with each other.

  With such a configuration, a light beam is generated by the light source, and the light beam from the light source is reflected in the direction of the object to be measured by the measurement point selection means in which a plurality of micromirrors that are individually inclined are arranged in a matrix, and the light detection means Reflected and scattered light from the irradiation point of the light beam on the object to be measured is detected via the measurement point selecting means, and at least the measuring point selecting means is displaced by the displacing means and the irradiation direction of the light beam on the object to be measured. The displacement amount of the measurement point selecting means and the luminance data of the light detected by the light detecting means are output in association with each other by the displacement meter control circuit.

  Further, the light detection means is disposed on the optical path between the light source and the measurement point selection means, and is reflected by the light branching means that branches the optical path from the measurement point selection means in two. Is received. Thereby, the light splitting means disposed on the optical path between the light source and the measuring point selecting means splits the optical path from the measuring point selecting means into two, and the light reflected by the light splitting means by the light detecting means Is received.

  Furthermore, the light detection means is a photomultiplier tube or an image pickup device, or a combination of the two, which can be switched to enable light detection. As a result, the reflected and scattered light from the object to be measured is detected by a photomultiplier tube or an image sensor, or a combination of the two is switched to detect the reflected and scattered light from the object to be measured.

  The light source is a laser light source or a white light source, or a combination of the two can be switched for irradiation, or a combination of laser light sources having different wavelengths can be switched for irradiation. Thereby, the laser light source or the white light source is used for irradiation, or a combination of the two or a combination of laser light sources having different wavelengths is used for irradiation.

  According to the first or third aspect of the present invention, the measurement point selection means are arranged in a matrix in an optically conjugate relationship with the focal position of the objective lens that focuses the light beam on the object to be measured. Among the plurality of micromirrors, at least one micromirror is tilted to reflect the light beam from the light source toward the object to be measured, and the reflected and scattered light from the measurement point of the object to be measured is reflected by the measurement point selection unit. By detecting through at least one micromirror, the measurement point can be arbitrarily selected, and the height of the measurement point on the object to be measured can be measured at high speed. Therefore, for example, the height of the foreign matter in the cell gap of the liquid crystal display panel can be inspected at high speed.

  According to the invention according to claim 2 or 5, at least one micromirror of the plurality of micromirrors of the measurement point selection means is arbitrarily selected and driven, so that a desired measurement point and The number of measurement points can be arbitrarily selected. Therefore, the height of an arbitrary measurement point on the object to be measured can be measured at a high speed.

  Further, according to the invention according to claim 4, the displacement meter unit is configured by including the light source, the measurement point selection means, the light detection means, the displacement means, and the displacement meter control circuit, and the displacement meter unit. Since the measurement point selection means is displaced in the direction of irradiation of the light beam to the object to be measured, the displacement of the measurement point selection means is expanded according to the magnification of the objective lens, and the optical axis direction of the objective lens The measurement accuracy of the minute height can be improved as compared with the case where the object to be measured is relatively displaced. Further, when the measurement accuracy is the same as the case of relatively displacing the object to be measured, the measurement of the displacement amount of the measurement point selection means can be performed roughly. Therefore, in this case, a special sensor such as an encoder or a linear scale for measuring the displacement amount is not required, and the displacement amount can be measured by counting the number of drive pulses of the displacement device. It will be easy. Furthermore, since the minute height at each measurement point can be measured with the objective lens focused on the object to be measured, the measurement point can be easily specified.

  Further, according to the invention according to claim 6 or 10, the light is reflected by the light branching means which is arranged on the optical path between the light source and the measurement point selection means and branches the optical path from the measurement point selection means in two. Since the received light is received, the light from the measurement point selecting means can be received without interfering with the light emitted from the light source.

  Furthermore, according to the invention according to claim 7 or 11, the photodetection means is a photomultiplier tube or an image pickup device, or a combination of the two can be switched to enable photodetection. When a double tube is used, the detection sensitivity is high, so that the light detection accuracy is improved, and the measurement accuracy of a minute height can be improved. In addition, when an image sensor is used, the height of a plurality of measurement points can be measured at the same time, and the minute height can be measured at a higher speed. Furthermore, if both can be switched in combination, they can be switched appropriately according to the purpose, and convenience is expanded.

  According to the invention according to claim 8 or 12, the light source is a laser light source or a white light source, or a combination of the two can be switched for irradiation, or a combination of laser light sources having different wavelengths can be switched for switching. By using a laser light source with multiple wavelengths, the wavelength of the laser light source can be selected according to the color of the ground at the measurement point of the object to be measured. It can be performed with high sensitivity. Further, when a white light source is used, light detection can be performed with high sensitivity without being affected by the color of the background of the measurement point of the object to be measured.

  According to the ninth aspect of the invention, the plurality of micromirrors of the measurement point selection means in which a plurality of micromirrors are arranged in a matrix are individually tilted to reflect the light beam from the light source toward the object to be measured. Detecting the reflected and scattered light from the irradiation point of the light beam on the object to be measured, and displacing the measuring point selection means in the irradiation direction of the light beam to the object to be measured, Since the luminance data of the detection light is output in association with each other, it is possible to easily configure a minute height measuring device attached to an existing microscope.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a conceptual diagram showing a first embodiment of a minute height measuring apparatus according to the present invention. This minute height measuring apparatus measures the height of the DUT 1 using a confocal optical system, and includes a light source 2, an objective lens 3, a measuring point selecting means 4, a light detecting means 5, The displacement means 6 and the control means 7 are intended to inspect a cell gap of a liquid crystal display panel at a high speed, for example.

The light source 2 emits a light beam and is, for example, a laser oscillator.
An objective lens 3 is provided opposite to the object to be measured 1. The objective lens 3 condenses the light beam from the light source 2 on the object 1 to be measured.

Measuring point selection means 4 is arranged in an optically conjugate relationship with the focal position of the objective lens 3. This measuring point selection means 4 arbitrarily selects a fixed point on the object 1 to be measured, and a plurality of micromirrors 10 that are individually tilted so that the light beam from the light source 2 is reflected in the direction of the object 1 to be measured. _{(1, 1)} to 10 _{(m, n)} are arranged in a matrix. The size of the micromirror 10 _(1,1) to 10 _{(m, n)} can be formed to about 16 μm square, for example, and the micromirror 10 _(1,1) to 10 _{(m, n)} Spot light of approximately the same size can be generated.

An imaging lens 8 is provided between the objective lens 3 and the measurement point selecting means 4 so as to coincide with the optical axis of the objective lens 3 and is generated on the object 1 to be measured by the objective lens 3. The image of the beam spot of the light beam is formed on the micromirror 10 _(1,1) to 10 _{(m, n)} . The objective lens 3, the measurement point selection unit 4, and the imaging lens 8 constitute a confocal optical system 9.

  A light detection means 5 is provided between the light source 2 and the measurement point selection means 4. This light detection means 5 detects the reflected and scattered light from the condensing point of the light beam collected on the device under test 1 by photoelectric conversion via the measurement point selection means 4, For example, a photomultiplier tube (PMT). The light detection means 5 is disposed on the optical path between the light source 2 and the measurement point selection means 4, and the light branching means 11 for branching the optical path from the measurement point selection means 4 into two, for example, half The light from the measurement point selection means 4 reflected by a mirror or the like can be received without interfering with the light beam emitted from the light source 2. The light detection means 5 is not limited to the PMT as long as it can detect light by photoelectric conversion.

  The confocal optical system 9 is provided with a displacement means 6. The displacement means 6 is for displacing the confocal optical system 9 in the optical axis direction, and includes a motor (not shown) and a position detection sensor, and the motor is controlled based on a control signal from the control means 7 described later. The confocal optical system 9 is driven to displace in the optical axis direction (directions indicated by arrows A and B in FIG. 1), the amount of displacement from a preset reference position is detected by the position detection sensor, and the detection signal Is sent to the control means 7.

A control means 7 is provided in connection with the measurement point selection means 4, the light detection means 5 and the displacement means 6. As shown in FIG. 2, the control means 7 arbitrarily selects and drives one of the plurality of micromirrors 10 _{(1, 1)} to 10 _{(m, n)} of the measurement point selection means 4. At the same time, the amount of displacement indicating the maximum luminance value is obtained as the height at the measurement point of the DUT 1 from the luminance of the light detected by the light detection means 5 and the amount of displacement of the confocal optical system 9. A control and processing unit 12, an A / D conversion unit 13, a memory 14, and a home computer (hereinafter referred to as “control PC”) 15.

The control and processing unit 12 measures the address information of the micromirrors 10 _{(1, 1)} to 10 _{(m, n)} corresponding to each measurement point designated in advance by the control PC 15 connected to the outside. The data is sent to the point selection means 4 to drive the micromirrors 10 _{(1, 1)} to 10 _{(m, n)} at the addresses specified by the address information. Further, a command signal related to the sampling interval and the number of samplings and the displacement speed specified in advance by the control PC 15 is sent to the displacement means 6, and the confocal optical system 9 is displaced at a predetermined speed by the maximum displacement amount determined by the command signal. Let Further, a conversion timing signal for activating the A / D conversion unit 13 at the sampling interval is output to the A / D conversion unit 13 and acquired from the A / D conversion unit 13 at the timing. The luminance data and the displacement amount data generated based on the detection signal of the position detection sensor input from the displacement means 6 at the timing are associated and written to the memory 14. Then, all the luminance data read from the memory 14 and the displacement data associated therewith are output to the control PC 15.

The A / D conversion unit 13 converts the analog signal input from the light detection means 5 into digital data, and performs digital conversion at a predetermined timing based on the conversion timing signal input from the control and processing unit 12. It is supposed to be. The memory 14 stores luminance data and displacement amount data in association with each other, and is, for example, a RAM. Then, the control PC 15 allows the operator to address information of the micromirrors 10 _{(1, 1)} to 10 _{(m, n)} corresponding to each measurement point, the displacement speed and sampling interval of the confocal optical system 9, and the number of samplings. Can be input, and the displacement 1 indicating the maximum luminance value from the brightness and displacement data output in association with each other from the control and processing unit 12 is measured at each measurement point 1 to be measured. The height is obtained, and the result is displayed on the display unit 15a.

Next, the operation of the minute height measuring apparatus configured as described above and the minute height measuring method performed using the apparatus will be described with reference to FIG.
First, in step S1, the control and processing unit 12 of the control means 7 sets the address information of the micromirrors 10 _{(1, 1)} to 10 _{(m, n)} corresponding to the measurement points input and designated in advance by the operator. In addition, various parameters such as a sampling interval for acquiring the displacement speed and displacement amount data of the confocal optical system 9 and the number of times of sampling are input from the control PC 15. When the coordinate position of each measurement point is measured in advance, it may be automatically set by fetching the data from the saved file into the control PC 15.

In step S2, the inputted various parameters are processed to set the driving order K = 1 to k of each micromirror 10 _(1,1) to 10 _{(m, n)} , and the driving is performed according to the set order K. The address information of the micromirrors 10 _{(1, 1)} to 10 _{(m, n)} to be sent is sequentially sent to the measurement point selection means 4.

In step S3, the measurement point selecting means 4 first measures the light beam emitted from the light source 2 by driving the micromirror 10 _{(1, i)} (see FIG. 1 ₎ set to K = 1. Reflects on the object 1 side. The light beam reflected by the micromirror 10 _{(1, i)} passes through the imaging lens 8 and the objective lens 3 and is condensed on the selected first measurement point on the object 1 to be measured. In this case, since the light beams reflected by the other micromirrors are directed in a different direction from the object to be measured 1, these light beams are not condensed on the object to be measured 1. .

The reflected and scattered light of the light beam generated at the first measurement point on the object to be measured 1 passes through the objective lens 3 and is condensed on the micromirror 10 _{(1, i)} by the imaging lens 8. The reflected and scattered light is reflected by the micromirror 10 _{(1, i)} toward the light source 2 and enters the light branching means 11, and is reflected by the light branching means 11 in a direction different from that of the light source 2. The light enters the light detection means 5.

  In step S4, the light intensity analog signal received by the light detection means 5 is converted into digital luminance data by the A / D conversion unit 13 of the control means 7. In this case, the A / D conversion unit 13 is predetermined at a predetermined timing by the conversion timing signal generated by the control and processing unit 12 based on the sampling interval and the sampling frequency data among the various parameters input from the control PC 15. Digital conversion is performed as many times as necessary.

  At the same time, the control and processing unit 12 sends a command signal regarding the sampling interval and the number of times of sampling and the displacement speed input from the control PC 15 to the displacement means 6 and drives the motor of the displacement means 6 to send the confocal optical system 9 to the command. It is displaced in the direction of arrow A or B shown in FIG. 1 at a predetermined speed by a displacement determined by the signal.

  In step S <b> 5, the control and processing unit 12 sequentially inputs luminance data digitally converted at a predetermined timing from the A / D conversion unit 13. At the same time, displacement data of the confocal optical system 9 is generated based on detection signals sequentially input from the position detection sensor of the displacement means 6 in synchronization with the above timing.

In this case, when the position of the measurement point of the DUT 1 coincides with the focal position of the objective lens 3 of the confocal optical system 9, substantially all of the reflected light from the focal position is micromirror 10 _{(1, i )} is reflected by condensing the reflecting surface of a result, the brightness value detected by the light detection means 5 (light intensity) is high. On the other hand, when the position of the measurement point of the DUT 1 is deviated from the focal position of the objective lens 3, the beam spot at the measurement point is blurred and enlarged, and the beam spot is placed on the micromirror 10 _{(1, i)} . The size of the image formed is larger than the size of the micromirror 10 _{(1, i)} . Therefore, the amount of light reflected by the reflecting surface of the micromirror 10 _{(1, i)} decreases, and the luminance value (light intensity) detected by the light detection means 5 decreases. The luminance value (light intensity) decreases as the amount of deviation of the measurement point from the focal position increases.

  In step S6, the control and processing unit 12 writes the luminance data and displacement data obtained at each timing in association with each other as information on the first measurement point in the memory 14.

In step S7, the control and processing unit 12 determines whether or not K = k. If "NO" is determined here, the process returns to step S3 to switch to driving of the micromirror 10 _{(1, i + 1)} set to K = 2, and the above steps S4 to S6 are executed. Then, luminance data and displacement amount data at the second measurement point of the DUT 1 are obtained, and these are associated with each other and written in the memory 14.

  On the other hand, if “YES” determination is made in step S 7, the acquisition of the measurement data for all the measurement points is completed, and the process proceeds to step S 8, where the control and processing unit 12 transmits the luminance data and displacement data of each measurement point from the memory 14. Are successively determined as the height of each measurement point on the DUT 1 and the result is displayed on the display unit 15a of the control PC 15.

  In the above embodiment, the case where the confocal optical system 9 is displaced has been described. However, the present invention is not limited to this, and the measured object 1 side may be displaced in the optical axis direction of the objective lens 3.

  FIG. 4 is a front view showing a second embodiment of the minute height measuring apparatus according to the present invention. This minute height measuring apparatus is disposed opposite to the object to be measured 1, and has an objective lens 3 that focuses a light beam on the object to be measured 1, and the object to be measured 1 with respect to the objective lens 3. As shown in FIG. 5, a light source 2 that irradiates a light beam and a plurality of micromirrors that are individually tilted so that the light beam from the light source 2 is reflected in the direction of the object to be measured 1 are arranged in a matrix. Measuring point selecting means 4 arranged in a line, light detecting means 5 for detecting reflected and scattered light from the irradiation point of the light beam on the object 1 to be measured 1 via the measuring point selecting means 4, and at least the measuring point Displacement means 6 for separating the selection means 4 from the objective lens 3 and displacing the object to be measured 1 in the irradiation direction of the light beam, and controlling the displacement of the displacement means 6 and the displacement amount and light of the measurement point selection means 4 The luminance data of light detected by the detection means 5 A displacement meter unit 17 having a displacement meter control circuit 16 that outputs in combination and each micromirror of the measurement point selection means 4 of the displacement meter unit 17 are individually driven and controlled to control the displacement of the displacement means 6. And a control means 18 comprising, for example, a host computer, which obtains the displacement indicating the maximum luminance value as the height of the measurement point of the object to be measured from the displacement and light luminance data output from the displacement meter unit 17. It is provided.

  The objective lens 3 and the imaging lens 8 that forms an image of the device under test 1 on the mirror surface of the measurement point selecting means 4 are provided in a lens barrel 19 to constitute a microscope. In FIG. 5, reference numeral 19 denotes a motor driver that drives the displacement means 6, reference numeral 20 denotes a motor controller that controls the motor driver 19, reference numeral 21 denotes a reflection mirror that reflects the light beam, and reference numeral 22. Is a light absorber that absorbs unnecessary light reflected by the measurement point selection means 4.

Hereinafter, the operation of the second embodiment and the minute height measurement method performed using the operation will be described in detail with reference to FIG. FIG. 6 shows a case where measurement points are set manually.
First, in step S11 shown in FIG. 6, an image on the object to be measured 1 acquired through the objective lens 3 is picked up by an autofocus camera (not shown) attached to the lens barrel 19 of the microscope and the objective lens 3 is captured. Is focused on the DUT 1.

  In step S12, various parameters such as a sampling interval and the number of times of sampling for acquiring the displacement speed and displacement amount data of the displacement meter unit 17 set in advance by the operator input to the control means 18 comprising a host computer are displayed. The data is input to the unit 17 and stored in the memory 11.

  In step S13, for example, the microscope is moved in the XY-axis direction based on the coordinate data of the first measurement point among the coordinate positions of the measurement points previously measured and stored in the control means 18, and the first The measurement point is set within the field of view of the objective lens 3. In this case, an image on the object to be measured 1 acquired via the objective lens 3 is picked up by an observation camera (not shown) attached to the lens barrel 19 of the microscope and displayed on the display unit of the control means 18. To do. The microscope may be moved manually while the operator observes the image displayed on the display unit. Further, it may be moved not on the microscope side but on the measured object 1 side.

  Here, the operator selects the mouse cursor 23 provided in the control means 18 on the screen of the display unit as a reference point on the flat surface in the vicinity of the measurement point and clicks the mouse to confirm it. Place the cursor 23 and click to confirm the measurement point. Thereby, frame information for driving the reference point and the micromirror corresponding to the measurement point of the measurement point selection unit 4 is created from the control unit 18 and output to the displacement meter unit 17. When the measurement points are close and, for example, as shown in FIG. 7A, a plurality of points, for example two measurement points, are observed in the same field of view, a flat point arbitrarily selected as a reference point first with the mouse. Click the point R on the surface, then click the point P1 of the measurement point, and click the point P2. The frame information is sent to the measurement point selection means 4 via the control and processing unit 12 and temporarily stored in a memory (not shown) provided therein.

  In step S14, the control and processing unit 12 of the displacement meter unit 17 turns off the illumination light source (not shown) that has been turned on for observing the autofocus and the surface to be measured, and the measurement light source 2, for example, a laser light source. Turn on.

  In step S15, the measurement point selection means 4 is driven based on the frame information, and the micromirrors corresponding to the reference point R and the measurement points P1 and P2 send the light beam from the light source 2 toward the object 1 to be measured. Tilt to reflect.

  In step S <b> 16, the control and processing unit 12 reads out the speed data and the sampling interval data for displacing the displacement meter unit 17 from the various parameters stored in the memory 11 of the displacement meter control circuit 16, and the motor controller 20. Send to. The motor controller 20 drives the displacement means 6 by pulse-controlling the motor driver 19 based on each data, and displaces the displacement meter unit 17 by a predetermined amount.

  When the displacement meter unit 17 is displaced, the conversion timing signal generated by the control and processing unit 12 is output to the A / D conversion unit 13, and the A / D conversion unit 13 is driven for a predetermined time and designated. Luminance data of light reflected and scattered from the reference point R and measurement points P1, P2 of the device under test 1 and detected by the light detection means 5 is taken in the specified order. Then, the displacement amount data of the displacement meter unit 17 at this time and the luminance data detected by the light detection means 5 are stored in the memory 11 in association with each other.

  In step S <b> 17, the control and processing unit 12 determines whether or not the measurement of the preset number of times of sampling has been completed. Here, when the measurement with respect to the reference point R and the measurement points P1 and P2 is not completed, the determination is “NO”, the process returns to step S16, the displacement meter unit 17 is further displaced by a predetermined amount, and new values at the respective points are obtained. The amount of displacement and brightness data are acquired. On the other hand, when all the measurements for the reference point R and the measurement points P1 and P2 are completed, the determination is “YES” and the process proceeds to step S18. The total amount of displacement can be detected by counting the number of pulses when the amount of movement of the displacement meter unit 17 per pulse of the motor controller 20 is known in advance.

  In step S18, the control and processing unit 12 determines whether or not the height measurement for all the measurement points set on the DUT 1 has been completed. Here, when the measurement has not been completed yet, “NO” determination is made and the process proceeds to step S19, where the light source 2 is turned off and the proof light source is turned on. Then, returning to step S16, the microscope is set to the next measurement point, and the height of the measurement point is measured in the same manner as described above. On the other hand, when the measurement for all the measurement points is completed, the determination is “YES” and the process proceeds to step S20.

  In step S20, the reference point and the measurement data at each measurement point are read from the memory 11 and sent to the control means 18. Based on the input reference points and the measurement data at each measurement point, the control means 18 determines a displacement amount indicating the maximum luminance value at each point as the height at each point. Then, the relative height is calculated by comparing the height of each of the measurement points, for example, points P1 and P2, with the height of the reference point R, and the display unit corresponds to each measurement point as shown in FIG. The height value is displayed. The display method is not limited to the above method, and any method such as list display may be used.

  The measurement point is not limited to the method of manually setting the measurement points as described above, and the measurement points may be automatically set and measured. In this case, in step S13 of FIG. 6, the control means 18 automatically sets and stores the measurement order of each measurement point in advance. Next, as shown in FIG. 8, for example, the microscope is moved and the first measurement point P <b> 1 is drawn into the field of view of the objective lens 3. Further, the acquired image obtained by the labor-saving observation camera shown in the figure is subjected to image processing to measure the distance between the center of the screen and the measurement point P1, and the measurement point P1 is finely moved by the same dimension as shown in FIG. Is set to the optical axis of the objective lens 3 to set a measurement point. Also, as shown in FIG. 5C, a point that is separated by a predetermined distance in the vicinity of the measurement point P1 is set as a reference point. In this case, for example, the size information is obtained from the measurement data of the measurement point P1 measured in advance and stored in the control means 18, and a point that is several times larger than the size in a predetermined direction is set as the reference point R. You may make it do. Thus, when the measurement point P1 and the reference point R are set, the micromirror of the measurement point selection unit 4 corresponding to the measurement point P1, the micromirror matching the optical axis of the objective lens 3, and the above Frame information for driving the micromirror corresponding to the reference point R is created by the control means 18 and output to the displacement meter unit 17. Hereinafter, if steps 14 to 20 are executed, the minute height of each measurement point on the DUT 1 can be measured.

  Further, according to the second embodiment, the profile at the measurement position can be measured. For example, as shown in FIG. 9A, the measurement method first confirms the position of the measurement point P1 from the acquired image of the observation camera, designates the position for measuring the profile with the mouse, and displays it on the screen. To do. Next, as shown in FIG. 4B, the micromirror of the measurement point selection means 4 corresponding to the profile measurement position is tilted and irradiated with a light beam to the profile measurement position to confirm the measurement position, and then illumination for observation The brightness of the reflected and scattered light at each measurement point on the measurement position is measured while turning off the light source and displacing the displacement meter unit 17 in a predetermined step. Then, the height of each point is calculated based on the maximum luminance value and the displacement amount data at each point, and the measured profile information is displayed on the screen as shown in FIG.

  In the above description, the case where the light source 2 is a single laser light source has been described. However, the present invention is not limited to this, and the light source 2 may be a plurality of laser light sources or white light sources having different wavelengths. It may be used by switching with. The wavelength of the laser light source or the white light source may be selected according to the color of the ground at the measurement point of the object to be measured. Since the laser light source has high luminance, the measurement sensitivity can be improved, and the white light source can be measured without being influenced by the color of the background of the object to be measured.

  The light detection means 5 is not limited to the PMT, but may be a CCD or CMOS image sensor, and these may be used by switching them with a changeover switch. In this case, the PMT is limited to point-by-point measurement, but the measurement accuracy can be improved because the light detection sensitivity is high. On the other hand, although the image sensor has a low detection sensitivity, it can simultaneously measure multiple points, so that the measurement speed can be improved.

Furthermore, when a two-dimensional image sensor such as a CCD or CMOS is used as the light detection means 5, the three-dimensional shape of the object to be measured can be measured. The measurement method is 10 micro-mirror 10 _(1,1) of the measuring point selection unit 4 as to correspond to the observation range of the observation camera as shown in (a) shown in FIG. (B) to 10 _{( m, n)} is provided, the micromirrors 10 _{(1, 1)} to 10 _{(m, n)} are tilted, for example, every two sheets as shown in FIG. The light beam is reflected toward the object to be measured 1 as shown by a solid line in FIG. 5, and reflected and scattered light from the object to be measured 1 is reflected by the same micromirror as shown by a broken line in the figure to perform two-dimensional imaging. The reflected light is detected by the light detection means 5 made of an element, and luminance data of a two-dimensional image is acquired. In the following, as shown in an enlarged view in FIG. 11 (b), the micromirrors 10 _{(1, 1)} to 10 _{(m, n)} are tilted in the order indicated by numerals in the figure, for example, and nine two-dimensional An image is acquired, and luminance data of each two-dimensional image is acquired. The micromirrors in other parts are also tilted in the order shown in FIG.

Next, the displacement meter unit 17 is displaced by a predetermined amount in a predetermined direction, nine two-dimensional images are acquired in the same manner as described above, and luminance data of each two-dimensional image is acquired. Hereinafter, when all of the luminance data of the two-dimensional image in the height direction of the device under test 1 is obtained by repeating this, the amount of displacement indicating the maximum luminance value of each measurement point on the device under test 1 corresponding to each micromirror Is calculated by the control means 18 and obtained as the height of each measurement point. Then, by displaying the result on the display unit of the control means 18, the three-dimensional shape of the DUT 1 can be represented. In order to avoid interference of reflected and scattered light from adjacent measurement points on the DUT 1 on the micromirror, the micromirrors 10 _(1,1) to 10 _{(m, n)} tilted simultaneously are At least every other sheet should be used. Preferably, when the micromirror has a size of 15 μm × 15 μm, the distance is 15 μm × 4 (sheets) = 60 μm or more. Thereby, the height measurement can be performed with high accuracy while avoiding the interference of light.

Furthermore, in the minute height measuring apparatus of the present invention, the case where the measurement point selecting means 4 is a plurality of micromirrors 10 _{(1, 1)} to 10 _{(m, n)} arranged in a matrix has been described. The measurement point selection means 4 may be a transmissive liquid crystal panel. In this case, each cell of the liquid crystal panel may be individually driven to transmit light, and a measurement point may be arbitrarily selected.

It is a conceptual diagram which shows embodiment of the micro height measuring apparatus by this invention. It is a block diagram which shows the structure of the control means of the said micro height measuring apparatus. It is a flowchart explaining the operation | movement of the minute height measuring apparatus by this invention, and the minute height measuring method implemented using it. It is a front view which shows 2nd Embodiment of the micro height measuring apparatus by this invention. It is a block diagram which shows the structure of the displacement meter unit of the said 2nd Embodiment. It is a flowchart explaining the operation | movement of the said 2nd Embodiment, and the micro height measurement method performed by setting a measurement point manually using it. It is explanatory drawing which shows the method of setting the said measurement point manually. It is explanatory drawing which shows the method of setting the said measurement point automatically. It is explanatory drawing which shows the method of measuring the profile in the designated measurement position. It is a top view which shows the example of the picked-up image on the to-be-measured object by the camera for observation, and the example of an arrangement | sequence of the micromirror of the measurement point selection means provided corresponding to the observation range. It is explanatory drawing which shows an example of the micromirror tilted simultaneously in the said measurement point selection means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Object to be measured 2 ... Light source 3 ... Objective lens 4 ... Measurement point selection means 5 ... Light detection means 6 ... Displacement means 7, 18 ... Control means 10 _(1,1) -10 _{(m, n)} , 10 _{(1 , I)} ... Micromirror 11 ... Optical branching means 16 ... Displacement meter control circuit 17 ... Displacement meter unit

Claims (12)

At least one of the micromirrors of the measurement point selection means, which is arranged in an optically conjugate relationship with the focal position of the objective lens for condensing the light beam on the object to be measured, and in which a plurality of micromirrors are arranged in a matrix. Tilt the micromirror to reflect the light beam from the light source toward the object being measured,
The light beam reflected by the at least one micromirror is condensed on the object to be measured by the objective lens,
Detecting reflected and scattered light from a condensing point of the light beam collected on the object to be measured via the at least one micromirror of the measuring point selecting means;
Detecting the amount of displacement by displacing the object to be measured relative to the objective lens in the optical axis direction;
A displacement amount indicating a maximum luminance value is obtained as a height of the measurement point of the object to be measured from the luminance of the light detected through the at least one micromirror and the detected displacement amount data.
A minute height measuring method characterized by the above.   2. The minute height measuring method according to claim 1, wherein the measuring point selecting means arbitrarily drives at least one of the plurality of micromirrors. A light source that emits a light beam;
An objective lens for condensing the light beam from the light source on the object to be measured;
Measuring point selection means in which a plurality of micromirrors arranged in an optically conjugate relationship with the focal position of the objective lens and individually tilted so that the light beam from the light source reflects toward the object to be measured are arranged in a matrix. When,
A light detection means for detecting reflected and scattered light from the light collection point of the light beam collected on the object to be measured via the measurement point selection means;
Displacement means for displacing the object to be measured relative to the objective lens in the optical axis direction and detecting and outputting the displacement amount;
Each micromirror of the measurement point selection means is individually driven and controlled, and the displacement of the displacement means is controlled, and the maximum is determined from the data of the luminance of the light detected by the light detection means and the displacement amount input from the displacement means. Control means for obtaining the amount of displacement indicating the luminance value as the height of the measurement point of the object to be measured;
A minute height measuring device characterized by comprising: A light source that generates a light beam that irradiates the object to be measured, and a measuring point selection unit that includes a plurality of micromirrors that are individually inclined so that the light beam from the light source is reflected in the direction of the object to be measured; Light detecting means for detecting reflected and scattered light from the irradiation point of the light beam on the object to be measured via the measuring point selecting means, and the irradiation direction of the light beam to the object to be measured using the measuring point selecting means And a displacement meter control circuit for controlling the displacement of the displacement means and outputting the displacement amount of the measurement point selection means and the luminance data of the light detected by the light detection means in association with each other. A displacement meter unit having
An objective lens for condensing the light beam from the light source of the displacement meter unit on the object to be measured;
The micromirrors of the measurement point selection means of the displacement meter unit are individually driven and controlled, and the displacement amount indicating the maximum luminance value is calculated from the displacement amount and light luminance data output from the displacement meter unit. Control means to obtain as the height of the measurement point;
A minute height measuring device characterized by comprising:   5. The minute height measuring apparatus according to claim 3, wherein the control means arbitrarily selects and drives at least one of the plurality of micromirrors of the measurement point selection means.   The light detection means is disposed on an optical path between the light source and the measurement point selection means, and receives light reflected by the light branching means that branches the optical path from the measurement point selection means in two. The minute height measuring device according to any one of claims 3 to 5, wherein:   The photodetection means is a photomultiplier tube or an image sensor, or a combination of the two, and each of them can be switched to enable photodetection. Micro height measuring device.   The light source is a laser light source or a white light source, or a combination of the two can be switched for irradiation, or a combination of laser light sources having different wavelengths can be switched for irradiation. Item 8. The minute height measuring device according to any one of Items 3 to 7. A light source for generating a light beam for irradiating the object to be measured;
Measuring point selecting means in which a plurality of micromirrors individually inclined so that the light beam from the light source is reflected in the direction of the object to be measured are arranged in a matrix;
Light detection means for detecting reflected and scattered light from the irradiation point of the light beam on the object to be measured via the measurement point selection means;
Displacement means for displacing the measurement point selection means in the irradiation direction of the light beam to the object to be measured;
A displacement meter control circuit that controls the displacement of the displacement means and outputs the displacement amount of the measurement point selection means and the luminance data of the light detected by the light detection means in association with each other;
A displacement meter unit characterized by comprising:   The light detection means is disposed on an optical path between the light source and the measurement point selection means, and receives light reflected by the light branching means that branches the optical path from the measurement point selection means in two. The displacement meter unit according to claim 9.   11. The displacement meter unit according to claim 9 or 10, wherein the light detection means is a photomultiplier tube or an image sensor, or a combination of the two is used to switch the light detection unit so that light can be detected.   The light source is a laser light source or a white light source, or a combination of the two can be switched for irradiation, or a combination of laser light sources having different wavelengths can be switched for irradiation. Item 12. The displacement meter unit according to any one of Items 9 to 11.

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