TWI402495B - Three-dimensional measuring device - Google Patents

Description

Three-dimensional measuring device Technical field

The present invention relates to a three-dimensional measuring device, and more particularly to a three-dimensional measuring device for measuring the shape of a comparatively high sample using an optical mechanism such as a conjugate focal length microscope.

Background technique

In recent years, a three-dimensional measuring apparatus for obtaining a conjugate focal point image of a sample such as an LCD or a semiconductor wafer by using a conjugate focal length microscope and measuring the surface shape (height) of the sample using the image has been provided. The three-dimensional measuring device uses a shallow-focus conjugate focusing optical microscope to move the focus position of the conjugate focal length optical microscope in the optical axis direction, and takes an optical image of the sample magnified by the microscope with a camera. The image data is stored in the memory. Then, from the captured image data, the pixel with the highest brightness is detected, and the pixel of the maximum brightness is collected, and one image is combined to obtain an extended focus image. Alternatively, the focus position (height) at which the maximum brightness is obtained is taken as the position of each pixel, and one image is created, and a height image or a cross-sectional view can be obtained.

The conjugated focal microscope is provided with a pinhole at a focus position and an optically conjugated position to prevent light passing outside the focus point, thereby obtaining a microscope that is more detailed than that of a general optical microscope. A conventional conjugate focal length microscope is illustrated in Fig. 1. Fig. 1 is a schematic view for explaining the basic principle of a conventional conjugate focal length microscope. 100 series light source, 101 series imaging lens, 102 series half mirror, 103 series Niepokov rotating the image disc, 104-series pinhole, 105-series objective lens, 106-series sample surface of the object to be measured, 107-series imaging lens, and 108-series imaging surface.

In Fig. 1, the parallel light output from the light source 100 is imaged by the imaging lens 101 at a specific pinhole 104 of the Niepokov rotating mirror disk 103. In front of the Niepokov rotating mirror disk 103, there is a half mirror 102 which penetrates the light of the imaging lens 101 and reflects the reflected light incident from the opposite direction (described later).

Light passing through the pinhole 104 enters the objective lens 105 and reaches the sample surface 106. The reflected light from the sample surface 106 is returned to the objective lens 105 and passed through the pinhole 104 to obtain a conjugate focus effect. The reflected light passing through the pinhole 104 enters the half mirror 102, changes the direction of 90 [∘] (π/2 [rad]), and is imaged on the imaging surface 108 through the imaging lens 107.

The Niepokov rotating mirror disk has thousands of pinholes, and by rotating the pinholes, thousands of lights will scan the sample face 106. The reflected light scans the imaging surface 108, and one image can be obtained on the imaging surface 108.

The conjugate focal length microscope does not allow light other than the focus point to pass, and the depth of field is shallower than that of a general optical microscope.

For example, as shown in Fig. 2, the sample 1201 having a flat mountain shape in the center portion is oriented in the Z-axis direction (height direction), and moves from the foot of the mountain to the top of the mountain to obtain an image while recording the time. The Z coordinate value.

A cross section of the mountain-shaped portion is taken along the broken line of Fig. 2 to form a third (a) figure. The third diagram (a) is a pattern in which the vertical axis is in the height (Z-axis direction) and the horizontal axis is in the X-axis direction. In this figure, for convenience of explanation, the horizontal axis is the position coordinate of the X-axis direction, and the position coordinate on the XY plane can also be used.

Fig. 3(b) shows the luminance values of the pixels of the height (Z-axis coordinate) at the position of the focus point in Z1, Z2, Z3, ..., Z7, Z8 in Fig. 3(a). In the third (b) diagram, the vertical axis is the height of the mountain shape, and the horizontal axis is the luminance value of the pixel at the height of the focus point (Z-axis coordinate) at Z1, Z2, Z3, ..., Z7, and Z8.

As shown in the third figure (b), it can be seen that the height of each focus point, that is, the Z coordinate position (Z1, Z2, Z3, ..., Z7, Z8) has the peak value of each brightness value (11, 12, 13). , ..., 17, 18). Further, the curve of the third (b) graph is hereinafter referred to as a Z curve.

In a conjugated focus microscope, the depth of field of this I-Z curve is shallower than that of a conventional optical microscope, and is a steep curve. Therefore, the position of the focus point can be defined by the Z coordinate value of the peak position of the luminance value. Therefore, the Z-curve is obtained for each pixel of the imaging surface, and the height information of each pixel position can be obtained.

However, when only the Z coordinate is changed and the image is acquired, the focus position, as shown in Fig. 4(a), has the maximum brightness value, the Z coordinate value cannot be defined, or the brightness is as shown in Fig. 4(b). The value is small and the Z coordinate cannot be defined. When the noise component is large, even if the gain is amplified, the measurement is not easy.

In addition, in order to capture two or more substances having greatly different reflectances, it is determined whether the level of the light receiving signal of the reflected light from the sample is within an appropriate range set in advance, and if it is outside the appropriate range, the gain of the received light gain is variable. The mechanism can adjust the signal position level to an appropriate range (for example, refer to Patent Document 1).

Further, in a biological microscope or the like, a PSF (Point Spread Function) obtained by observing a fluorescent bead is used to perform a three-dimensional deconvolution (Dec Onvolution), improve the spatial decomposition ability.

[Patent Document 1] Japanese Patent Laid-Open No. 3568286

Invention The problem to be solved by the invention

However, in a sample containing two or more substances having greatly different reflectances (or transmittances), the reflectance (or transmittance) of light having a portion to be measured is largely different depending on the composition of the sample. . When the height of the measurement target portion of such a sample is measured by the above-described conventional measuring device, accurate measurement cannot be performed due to the difference in reflectance of the measurement target portion.

For example, when a sample of residual photoresist on a chromium vapor-deposited film having a high reflectivity such as a mirror surface is blended with a chrome film, when the amount of light irradiated by the microscope is set, the illuminance is insufficient for the resist portion. The noise was buried. As a result, due to noise, the height at which the maximum brightness is accidentally detected is erroneously detected as the height of the photoresist.

Due to the structure of the sample, insufficient illumination or reflected light is generated. This state will be described with reference to Figs. 16 to 18.

Fig. 16 is a perspective view and a cross-sectional view of a hypothetical sample which will be described below. The sample has a central portion having a height A and a central portion having a height B and a bottom portion having a height C, and the height is gradually increased in the order of A, B, and C. The bottom is the bottom of the deep trench structure, and has a steep cone shape with a continuous height between the outer peripheral portion and the bottom portion and between the bottom portion and the central portion. In addition, this sample is composed of a single substance.

Figure 17 is a height image, a cross-sectional view, and an all-focus image measured at the outer periphery of the sample shown in Figure 16 under the most appropriate illumination. Peripheral illumination When the illumination is most suitable, since the illumination of the bottom is narrow due to the width of the bottom, the light beam from the objective lens is shielded from the outer peripheral portion or the central portion before convergence. Moreover, the reflected light at the bottom is also scattered by the taper. Therefore, in an all-focus image, the bottom is quite dark (such as a brightness value of 0). Of course, the cone body is also very dark because the illumination light is not reflected by the objective lens. Therefore, when the focus position used to change the shooting position is high, the camera image is accidentally measured for noise (for example, a brightness value higher than 0), and the height is then used, as shown in the height image and the cross-sectional view of FIG. The measurement result is a protrusion like a needle.

On the other hand, Fig. 18 is a height image, a cross-sectional view, and an all-focus image measured at the bottom of the sample shown in Fig. 16 under the most appropriate illumination. When the most suitable illumination is applied to the bottom, since the reflected light of the peripheral portion and the central portion is too strong, even the blurred image passing through the non-focus surface of the pinhole disposed at the conjugate focal point exceeds the dynamic range of the camera. And cause white vision. Due to the type of camera, when there is too much incident light in one part of the shooting surface, the part that produces no incident light can also observe the phenomenon of strong signal (such as smear or blooming) in the non-focus. The surface also exceeds the dynamic range. As a result, the maximum brightness is also measured at a position different from the actual height. As shown in the sectional view of Fig. 18, a cross-sectional view is formed which is flat at the height A' at which the maximum brightness is finally measured (for example, the final position of the Z scan).

Thus, due to the above phenomenon and the well-known diffraction phenomenon, when there is a bright portion in the vicinity, there is a tendency that the maximum luminance position shifts to the height of the bright portion. Improvements are known to increase the likelihood of problems with such phenomena or noise when applied using the measurement method of deconvolution. However, therefore, a large memory capacity and calculation time are required, and a short measurement time (processing time) is required. Industrial use is not suitable. It is not effective for shooting images that are out of range of the camera.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sample having a plurality of measurement target portions having different light reflectances and a measurement target portion which is likely to cause insufficient illumination light and reflected light due to a three-dimensional structure. The three-dimensional measuring device capable of accurately measuring the accuracy can also be surely performed within a predetermined time.

Means to solve the problem

In order to achieve the above object, the three-dimensional measuring apparatus of the present invention comprises a conjugated focus microscope for amplifying an optical image of a sample having a first and a second measurement target portion having different reflectances; and the photographing is performed by the conjugate focal length microscope After the optical image of the sample, a camera that outputs the image data, and a light quantity variable light source that irradiates the sample with the light for imaging; and the focus of the conjugate focal length lens relative to the sample is A drive mechanism that changes in the direction of the optical axis and a control unit that is coupled to the camera, the light source, and the drive mechanism. The control unit includes a memory, a first image acquisition control unit, a second image acquisition control unit, and a calculation unit. The memory memory displays light quantity setting data of the first and second light amounts which are set in advance corresponding to the first and second measurement target portions of the sample; the first image acquisition control means stores the first image acquisition control means in the memory a light amount setting data, wherein an amount of light emitted by the light source is set, and in this state, an optical image of the sample is captured by the camera while changing a focus position of the conjugate focal length microscope with respect to the sample by the driving mechanism To get the image of it. The second image acquisition control means stores the second amount of light in the memory Setting data to set the amount of light emitted by the light source, and in this state, the optical image of the sample is captured by the camera while the focus position of the conjugate focal length microscope relative to the sample is changed by the driving mechanism It shoots images. The calculation means selects, from the captured image obtained by the first and second image acquisition control means, a luminance value included in a pixel region within a maximum range set in advance, and obtains a luminance value of the selected pixel region in the foregoing The height of the first and second measurement target portions is calculated based on the focus position of the conjugate focal length microscope at the time of the image in a wide range.

Further, the height measuring device of the present invention controls a conjugate focal length microscope for amplifying a sample, a light source for irradiating the sample, a dimming control unit for adjusting the amount of light of the light source, a Z-axis driving unit for driving the Z-axis to change the focus height, and photographing. The camera and measuring device of the image of the conjugate focal microscope, and the height of the sample is measured from the image taken by the camera. The height measuring device has a linear scale, and the control unit moves the Z-axis, reads the linear scale data and the image of the camera, compares the brightness value of the previous image, and records the pixel with higher brightness value and its Z coordinate.

Moreover, the height measuring device of the present invention is preferably a picture obtained by the same process as the height measurement before the measurement is performed, and the peak value or the representative value of the preset image area is used as a parameter of the dimming, and the parameter is determined according to the parameter. Whether or not to perform automatic dimming within the specified range, find the optimum light amount value.

Effect of invention

Therefore, the sample is irradiated with light of a light amount suitable for each of the reflectances of the first and second measurement target portions, and an enlarged image thereof is obtained. Therefore, when the sample has the first and second measurement target portions having different reflectances, the test may be performed according to the measurement. The target portion is detected, and the focus position at which the maximum brightness is formed is detected, whereby high-accuracy height measurement can be performed. When the sample has a three-dimensional structure and is easy to generate an illumination target or a portion of the measurement target having insufficient reflected light, the focus position of the measurement target portion can be detected, and high-accuracy height measurement can be performed.

In other words, according to the present invention, it is possible to provide a sample having a plurality of measurement target portions having different light reflectances and a sample having a three-dimensional structure, which is likely to generate illumination light and insufficient reflection light, and may be in a predetermined time. A three-dimensional measuring device that accurately measures the accuracy is performed.

The best form for implementing the invention

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are attached to the components having the common functions, and the description is omitted as much as possible in order to avoid redundancy.

(First embodiment)

The structure of the height measuring device using the conjugate focal length microscope of the present invention will be described with reference to Fig. 5. Fig. 5 is a schematic block diagram showing the structure of an embodiment of the height measuring device of the present invention. The height measuring device is almost the same structure as the line width measuring device, and the difference in structure is that the microscope includes the microscope of the part of the conjugate focus shown in FIG. 1 and has the correct Z coordinate (height coordinate). Linear scale, with height and height measurement mechanism for image and Z coordinates from image sensors such as cameras.

In Fig. 5, a 150-series camera, a 151-series microscope, a 152-series objective lens, a 153-series sample, a 154-series sample stage, a 155-series Y-axis drive unit, a 156-series X-axis drive unit, and a 157-series linear scale, 158 Z-axis drive unit, 159 series XYZ axis control The system is a 160-series PC (Personal Computer), a 161-series light source, a 162-series light source control unit, and a 163-series height measuring unit.

The light source 161 is a metal enclosed in a bulb which is a metal halide compound (for example, a mercury lamp or the like). The camera 150 can be an image sensor that can perform continuous shooting such as a TV (Tele-Vision) camera.

Further, the Z-axis mechanism for moving the focus position uses a fine-motion Z-axis mechanism (for example, flatness error: 10 [nm]) which is excellent in flatness in the horizontal direction even if the position of the Z-axis is changed.

In the above figure, the sample is moved up and down in order to move the focus position. However, it is also possible to move the objective lens or the rotator having the objective lens or the entire microscope up and down. Furthermore, all of these can be moved.

The light output from the light source 161 is input to the microscope 151, passes through the objective lens 152, and reaches the surface of the sample 153. The sample 153 emits the reflected light of the arriving light, and the reflected light that has been emitted again passes through the objective lens 152 to be imaged on the imaging surface of the camera 150.

The camera 150 captures an image formed on the imaging surface, converts it into an image signal, and outputs it to the PC 160. Thereby, the captured image is read by the PC 160, and image processing is performed.

The position of the focus point of the sample 153 and the designation of the measurement point are performed by the PC 160. In other words, the PC 160 is controlled by the XYZ axis control unit 159 to control the X-axis drive unit 156, the Y-axis drive unit 155, and the Z-axis drive unit 158. For example, by controlling the Z-axis driving unit 158, the Z coordinate is relatively changed, and the distance between the sample 153 and the camera 150 and the sample 153 and the height of the pinhole of Nipkov becomes the designated focus point position.

In order to explain the automatic dimming mechanism of the above-described line width measuring device, the fifth, sixth, seventh, and eighth drawings are used at the same time. 6 to 8 are flowcharts for explaining an embodiment of the automatic dimming processing procedure of the height measuring device of the present invention using a conjugate focal length microscope.

In Fig. 6, the user has fixed the sample 153 to the sample stage 154 to correspond to the measurement program (measurement method) of the sample to make the height measuring device operate.

First, in the dimming area setting step 601, the user sets the X-Y area for dimming via the user interface of the PC 160 in cooperation with the sample 153.

In the Z-axis movement range setting step 602, the user specifies the range of the Z-axis for which the height measurement is performed.

In the initial target range setting step 603, the user sets the initial target range (upper limit and lower limit) of the automatic dimming.

At the Z-axis start position shifting step 604, the Z-axis is moved to the start position of the range set in the Z-axis movement range setting step 602 or to a position suitable for automatic dimming.

In the automatic dimming step 605, the program shown in Fig. 8 which will be described later is executed.

In the height measurement program step 606, while the Z axis is moved in the Z coordinate range set in the Z axis movement setting step 602, the subject image and the Z coordinate position in the region set in the dimming area setting step 601 are acquired, and execution is performed. Processing of pixels with brighter brightness and their coordinate positions.

In addition, in order to realize the above embodiment, the microscope 151 shown in FIG. 5 needs to be a conjugate focal length microscope, and in order to obtain the correct Z coordinate value, it is necessary to have a linear scale 157, the image obtained from the camera 150 and the linear marker. Degree 157 Z The height measuring unit 163 whose height value can be measured.

When the height measurement program step 606 is performed, the height (Z coordinate value) corresponding to each pixel position of one image can be determined.

The height measurement procedure step 606 is illustrated in a flow chart of FIG.

As shown in Fig. 7, in the video 1 acquisition step 701, the video 1 at the start position is acquired. Then, at step Z of step Z, the Z coordinate is obtained.

Next, in the Z-axis moving step 703, the predetermined predetermined amount of focus point position is moved in the direction from the start position to the end position of the Z coordinate.

Then, in the video 2 acquisition step 704, the new video 2 is acquired, and in the Z coordinate acquisition step 705, the Z coordinate value of the image is obtained.

In the luminance value comparison processing step 706, the luminance values are compared for the corresponding pixel positions of the video 1 and the video 2.

Then, in the luminance value and Z coordinate update step 707, the image 1 is updated with pixels having a higher luminance value than the luminance value, and the Z coordinate of the updated pixel is recorded.

At the Z coordinate end position determining step 708, it is determined whether or not the current Z coordinate is the end position, and when the non-end position is reached, the process returns to the Z axis movement step 703. Moreover, when it is the end position, the process of the flowchart of FIG. 7 is completed, and it progresses to the brightness average acquisition step 607 of FIG.

As described above, by performing the processing of the height measurement program described in the flowchart of FIG. 7, the image 1 becomes the image in the Z-axis moving range corresponding to the full pixel position, leaving only the brightest luminance value, and has the brightest The Z coordinate value of the pixel.

Returning to Fig. 6, in the luminance average obtaining step 607, the average value of the luminance of the image 1 in the dimming region set in step 601 is obtained.

Then, in the target range upper limit determining step 608, it is determined whether or not the average value of the image 1 luminance values acquired in the luminance average obtaining step 607 is greater than a predetermined target upper limit value. When the average value of the brightness of the image 1 is greater than the target upper limit value, the process moves to step 609, and if not, the process moves to step 610.

In the automatic dimming target upper limit lowering step 609, the automatic dimming target upper limit value is lowered by a predetermined value, and the Z-axis start position moving step 604 is returned.

In the target range lower limit determining step 610, when the average value of the brightness of the image 1 is smaller than the target lower limit value, the process proceeds to step 611, and if not, the process of the flowchart of Fig. 6 is ended.

In the automatic dimming target lower limit value increasing step 611, the target lower limit value of the automatic dimming is increased by a predetermined value, and the Z-axis start position shifting step 604 is returned.

According to the embodiment of Fig. 6 described above, the optimum amount of light can be set in the Z-axis movement range.

Next, with reference to Fig. 8, an automatic dimming procedure step 605 of Fig. 6 will be described.

First, the luminance average obtaining step 801 acquires a new image from the camera 150 at the current Z coordinate, and calculates an average value of the brightness of the dimming region set in the dimming region setting step 601.

In the target range upper limit determining step 802, it is determined whether the average value of the luminances of the luminance regions is greater than a predetermined target upper limit value. When the average value is greater than the target upper limit value, the process moves to step 803, and if not, the process moves to step 804.

In the automatic dimming target upper limit lowering step 803, the amount of light is lowered by a predetermined value, and the brightness average obtaining step 801 is returned.

In the target range lower limit determining step 804, when the average value of the brightness of the brightness area is less than the target lower limit value, the process moves to step 805. If not, the process of the flowchart of FIG. 8 is ended, and the process proceeds to FIG. Height measurement procedure step 606.

In the automatic dimming target lower limit value increasing step 805, the amount of light is increased by a predetermined value, and the brightness average obtaining step 801 is returned.

Further, in the embodiments of Figs. 6 to 8, the average value of the brightness of the image 1 of the dimming area is obtained, and it is determined whether or not the average value of the brightness values is larger than a predetermined target upper limit value. However, in addition to the above average value, it is of course possible to represent a representative value (central value or the like) other than the peak value or the average value.

Further, steps 609 and 611 are not limited to correcting the predetermined amount, and may be halved by a predetermined amount at the time of correction. Further, the initial predetermined amount is set to the upper limit value as 1/2 of the difference between the current target upper limit value and the physical upper limit value. The same is true for the lower limit.

As described above, the present invention is a height measuring device using a conjugate focal length microscope, which has a dimming control unit that adjusts the amount of light of the light source, has a control unit that can drive the XYZ axis, has a linear scale at the Z coordinate, and exerts a side to make Z The axis moves, reading the linear scale data and the microscope image, comparing the brightness value of the previous image with each pixel, and recording the data with higher brightness value and the Z coordinate when the brightness value is obtained.

Before performing the measurement, the peak or representative value of the preset image area is used as the parameter of the dimming in the image obtained by the same process as the height measurement, and the parameter is automatically dimmed to determine whether the parameter is within the specified range. The most suitable amount of light.

Thereby, the following problem can be solved, that is, the Z-curve (the graph of the luminance value and the Z coordinate) applied to the height measuring device with the conjugate focal length microscope in the Z-axis by the automatic dimming of the conventional line width measuring device The range of movement reaches the maximum brightness value in almost the full range, or the brightness value decreases in almost the entire range of the Z-axis movement range.

That is, before the height measurement of the present invention, the peak or representative value of the preset image area is used as the parameter of the dimming in the image obtained by the same process as the height measurement, and whether the parameter is within the specified range is automatically performed. Dimming to find the most suitable amount of light.

The following describes an embodiment applied to the three-dimensional measuring device using the above-described automatic dimming function of the present invention. In this embodiment, the microscope of the height measuring device of Fig. 5 uses a conjugate focal length microscope with a microlens turntable.

A TV camera that captures an image magnified by this conjugate focal microscope is a high-speed reader. The microscope can be used for cameras up to 360 [fps] because it can obtain images up to 360 [fps]. However, here, the description is made with a camera of 120 [fps].

First, the Z-axis driving unit 158 for moving the focus position uses a fine-motion Z-axis mechanism (flatness error: 10 [nm]) which is excellent in flatness in the horizontal direction even if the position of the Z-axis is changed. . Here, the Z-axis driving unit 158 is equipped with a high-decomposition linearity scale for obtaining high-accuracy linearity with high accuracy, and Z-axis coordinates (Z-coordinates) are obtained from the linear scale. In addition, the coordinate movement of the Z-axis is described in the form of moving between the conjugate focal point optical unit and the objective lens, and as long as the focus position or the focal length can be moved, the sample can be moved, or the entire microscope can be operated, or only Nie Po can be made. Cove rotates the mirror to move slightly.

The Z-axis coordinate and the camera image data and the data processing for performing arithmetic processing when the Z-axis is moved and the focus position is changed are set on the PC 160.

Fig. 9 shows the image obtained by moving the Z-axis from the focus position A to the focus position E with the resist pattern as the sample, and obtaining the image at each focus position when the image is obtained. 901 series chrome mask, 902 series photoresist film, 901-1 series bottom chrome 901 vapor deposition surface (top) image, 902-1 series photoresist film 902 image, 903 series photoresist film 902 cone Image of the department.

At the focus position A, the surface of the chrome mask 901 and the photoresist film 902 are not focused, and all of the images 901-1, 902-1, and 903 are black images.

At the focus position B, the vapor deposition surface (top surface) 901-1 of the chromium 901 is focused, and the brightest image of the region of the vapor deposition surface 901-1 is obtained.

At the focus position C, the brightest image of the tapered portion 903 at the intermediate position between the chrome vapor deposition surface 901-1 and the upper surface 902-1 of the photoresist film is obtained.

At the focus position D, the upper surface of the photoresist film 902-1 is focused to obtain the brightest image of the image 902-1 area on the photoresist film surface 902.

At the focus position E, it is impossible to focus again, and an image of darkness is obtained.

In fact, since the focus position A~E is 2 [μm], and the Z axis is changed (displaced) in 1 second, if 120 [fps] camera is taken, 120 image data can be obtained, so the Z axis information A decomposition energy of about 16.6 [nm] can be obtained by the following formula.

Further, when a high-speed camera is used, the decomposition information of the height information can be further improved.

2[μm]/120≒0.0166[μm]≒16.6[nm]The above decomposition energy Z The axis coordinate and the image data corresponding thereto are stored in the data processing, and the arithmetic processing is performed to obtain the data of the Z-axis position coordinate when the brightness level of each pixel of the pixel data reaches a peak value.

Based on this data, when specifying two areas of height in the image, the height dimension can be measured from the difference in height information of the area.

Further, the Z-axis information data in this screen can be analyzed by displaying the cross-sectional shape in the screen on the 3D (three-dimensional) screen.

By displaying all the image data at the time of shooting, it is also possible to display a stereoscopic image with a deep depth of focus.

Since the conjugate focal length microscope with the microlens turntable has the characteristics of being brighter than the conventional conjugate focal microscope, it is possible to perform high-magnification measurement which is conventionally impossible to observe, and the selection of the objective lens can be performed to measure the range width.

As described above, in the embodiment described in FIG. 9, a three-dimensional measuring device having a conjugate focal length microscope that magnifies an inspection object (sample) and obtains a shallow depth of focus image is realized. A conjugate focal length microscope is used to input illumination light (for example, white light), a high-accuracy Z-axis drive unit for changing the focus position of the microscope, a camera for taking an enlarged image, a PC, and a PC to memorize the image data output from the camera. The memory unit, the automatic dimming unit that keeps the brightness caused by the difference in the reflectance of the object to be inspected, and the brightness position of each pixel from the coordinate position data of the Z-axis and the image data are processed to obtain the data for the three-dimensional measurement. The control unit is configured to perform measurement control using the data.

Moreover, the optical system of the conjugate focal length microscope is characterized in that the structure of the Niepokov rotating mirror disk and the microlens turntable is synchronously rotated. Brightness can also be measured at high magnifications that are not possible with conventional co-focus displays. Since the brightness of the microlens turntable can be obtained, a very high speed reading can be performed, and an image of up to 360 [fps] can be obtained, and in the case of three-dimensional measurement, high speed processing can also be performed.

(Second embodiment)

Fig. 10 is a view showing the structure of a three-dimensional measuring device according to a second embodiment of the present invention. This three-dimensional measuring device has a Nipkow-type conjugate focal length microscope 10.

In the conjugate focal length microscope 10, the objective lens 11 irradiates the light output from the light source 20 to the sample 30, and the reflected light of the irradiation light of the sample 30 is used to obtain a conjugate focus image. The conjugate focal length microscope 10 has a conjugate focal point scanner 12 that uses a Niepokov rotating image disc, and scans the reflected light passing through the objective lens 11 at a pinhole provided at a confocal position.

The light source 20 is a light source using a metal halide lamp, and the amount of light (illuminance) and the wavelength frequency range can be changed by an electric aperture or a filter. When the illumination light is irradiated to the sample, there is a case where the conjugate focus scanner 12 is used and a case where it is not used.

The camera 40 is connected to the above-described conjugate focus scanner 12, and reads a conjugate focus image scanned by the conjugate focus scanner 12 as image data. In the conjugate focal length microscope 10, since a maximum 360 fps (picture/second) image can be obtained, it is preferable to use a camera having a maximum of 360 fps. In the present embodiment, a 120 fps CCD camera is used.

The drive unit 50 moves the focus position of the conjugate focal length microscope 10 with respect to the sample 30 in the vertical (Z-axis) direction, that is, the optical axis direction of the conjugate focal length microscope 10 in accordance with the activation instruction of the control unit 60. The drive unit 50 uses even the Z-axis direction The position of the movement, the horizontal direction (X, Y direction) is still unchanged, the flatness is excellent, the fine-motion Z-axis mechanism (flatness error: 10 nm). The driving unit 50 obtains the high-accuracy information with high accuracy, and is equipped with high-decomposition energy, and the Z-axis coordinate obtained thereby is controlled to coincide with the instruction of the control unit. Further, in the present embodiment, the case where the entire operation of the microscope is operated by the driving unit 50 will be described. However, the sample 30 can be moved as long as the focus position can be moved, and only the Niepokov rotating mirror or the objective lens can be moved.

The control unit 60 is a digital signal processing unit such as a CPU, a DSP (Digital Signal Process), or a PGA (Programmable Gate Array), and is configured as follows.

Fig. 11 is a block diagram showing the functional structure of the control unit 60. The control unit 60 includes a main control unit 61, a first video acquisition control unit 62, a second video acquisition control unit 63, a height calculation unit 64, and two memory units 65 and 66. The main control unit 61, the first video acquisition control unit 62, the second video acquisition control unit 63, and the height calculation unit 64 realize their functions by a signal processing unit.

The main control unit 61 includes a measurement actor that controls the three-dimensional measurement device, and also has an interface function of receiving a transmission signal between the light source 20, the camera 40, the drive unit 50, and a display unit (not shown).

When the sample 30 has a plurality of measurement target portions having different light reflectances, the light amount setting data indicating the most suitable light amount value set in advance in the measurement target portion is stored in the memory 65 in accordance with the identification information of the measurement target object. For example, when the sample 30 is formed by a pattern of chromium formed on the glass surface, generally, the top surface of the chromium has a high light reflectance, and the glass surface reflectance is lower than the top surface of the chromium. Therefore, at this time, it is set corresponding to the reflectance of the top surface of the chromium. The first light amount setting data and the second light amount setting data set corresponding to the reflectance of the glass surface are stored in the memory 65. Further, the memory 66 is used to store image data obtained by the first and second image acquisition control units 62 and 63 to be described later.

The first video acquisition control unit 62 sets the amount of light emitted by the light source 20 based on the first light amount setting data stored in the memory 65. The first video acquisition control unit 62 drives the drive unit 50 while the light of the first light amount setting material setting light amount is irradiated from the light source 20 to the sample 30, and the focus position of the conjugate focal length microscope 10 is in the optical axis direction. The camera 40 is moved in stages to capture an image of the sample 30 at each focus position. Whenever the image of the sample 30 at each focus position is acquired by this photographing, the brightness value is compared between the pixels at the same position as the maximum brightness image. When the brightness value of the current image is high, the brightness value of the pixel of the maximum brightness image is updated and stored in the memory 66. At the same time, the focus position of the conjugate focal length microscope 10 when the pixel having the high luminance value is captured is stored in the memory 66 corresponding to the pixel. This becomes a height image. Further, since the initial value of the maximum luminance image is 0, the initial image obtained by moving the focus position to the first position directly becomes the maximum luminance image at that point in time.

The second video acquisition control unit 63 sets the amount of light emitted by the light source 20 based on the second light amount setting data stored in the memory 65. Then, the same processing as that of the first video acquisition control unit 62 is performed, and the luminance value and the focus position are stored in the memory 66. The processing of the first and second video acquisition control units 62 and 63 is performed in advance with the speed at which the video is acquired.

The height calculation unit 64 controls the acquisition of the first and second video acquisition control units 62 and 63, and finally remains in the same two maximum luminance images of the memory 66. Between the pixels, the upper limit value of the preset brightness value is not exceeded, and one brightness image is synthesized by using pixels of a larger brightness value. A height image is synthesized in the same manner as the pixels of the synthesized luminance image. The upper limit is the same as or slightly lower than the saturation level of the camera. The height calculation unit 64 can also automatically calculate the height of the top surface of the chrome from the composite height image with respect to the glass surface, and if the height exceeds a predetermined range, the display unit outputs a warning to the display unit.

Next, the height measuring operation of the three-dimensional measuring device constructed as above will be described in accordance with the processing procedure of the control unit 60. Figure 12 is a flow chart showing the processing procedure and processing contents. Here, as described above, the sample 30 is exemplified by a case where a chrome pattern is formed on a glass surface.

The amount of light recorded in the memory 65 with a corresponding pre-set to the reflectance of the top surface 31 of the chromium setting information OP ₁ and corresponds to the reflection of glass deposited surface 32 of the light quantity setting of the configuration data OP _2. The light amount setting materials OP ₁ and OP ₂ are photographed by the camera 40 by manually irradiating the sample 30 with light while actually irradiating the sample 30 with a method known as Patent Document 1, and manually or from the image data. Automatically determine the most suitable amount of light. Typically, the top surface 31 of the chrome is mirror-like and has a higher reflectance than the reflectivity of the glass surface 32. Therefore, the value of the first light amount setting data OP ₁ is set such that the light amount is smaller than the value of the second light amount setting data OP ₂ .

The control unit 60 first performs image acquisition control by the first image acquisition control unit 62 as follows. That is, in step 3a, 65 is read from the memory corresponding to the top surface 31 and the chromium amount is set the setting information OP _1.

In step 3b, the light amount of the light source 20 is adjusted according to the light amount setting data OP ₁ read as described above. Thereby, the light of the light amount specified by the light amount setting data OP _{1 is} irradiated from the light source 20 to the sample 30.

In this state, the first video acquisition control unit 62 starts the video acquisition from the first focus position (A in FIG. 14) in step 3c.

Fig. 13 is a flow chart showing the processing contents of the imaging control (steps 3c and 3g) of the first and second video acquisition control units. First, in step 4a, the first video acquisition control unit 62 initializes each pixel value of the maximum luminance image and the height image to zero. Next, in step 4b, the first video acquisition control unit 62 controls the drive unit 50 to move the focus position to A shown in Fig. 14.

Then, in step 4c, the main control unit 61 acquires the image IMG captured by the camera 40. In essence, at the same time, in step 4d, the position coordinate data of the correct Z-axis direction of the focus position A is obtained from the scale of the conjugate focal length microscope 10.

Next, in step 4e, the luminance value is compared for each pixel between the image IMG (A) of the focus position A currently acquired and the maximum luminance image IMG _{MAX1 stored} in the memory 66. As a result of this comparison, if the luminance value is IMG (A) > IMG _MAX1 , in step 4g, the pixel is written to IMG _MAX1 at IMG (A) and updated. At the same time, the pixel of the height image IMGZ _MAX1 is updated with the position coordinate data obtained in step 4d. The processing of steps 4e to 4g is performed on all the pixels in the image captured by the camera 40.

Then, the first video acquisition control unit 62 returns from step 4h to step 4b, and controls the drive unit 50 to move the focus position to B shown in FIG. Then, in steps 4c to 4g, similarly to the case of the focus position A, the acquisition of the image, the comparison with the maximum luminance image IMG _{MAX1 stored} in the memory 66, and the maximum luminance image IMG _MAX1 and the height according to the comparison result are performed. Update processing of image IMGZ _MAX1 . Thereafter, similarly, the above-described processes of steps 4b to 4h are repeatedly performed until it is detected in step 4h that the focus position has reached E shown in FIG. The maximum brightness image IMG _MAX1 when it arrives at E is also called an all-focus image.

Fig. 14 is a view showing an example of a conjugate focus image obtained at each focus position A to E during the processing of the first image acquisition control unit 62. In this figure, the region 301 of the conjugate focus image shows the image of the vapor-deposited surface (top) of the glass 32, the area 302 shows the image of the top surface of the chrome 31, and the area 303 shows the image of the taper of the chrome 31.

In Fig. 14, in the focus position A, it is impossible to focus, and all the corresponding areas are dark images. At the focus position B, since the reflectance of the glass 32 is small with respect to the reflectance of the chrome 31, an image in which all areas reflected by the vapor deposition surface of the glass 32 are dark is obtained. At the focus position C, the taper portion at the intermediate position between the glass vapor deposition surface 32 and the top surface 31 of the chrome is focused to obtain the brightest image of the region 303. At focus position D, focus on the top surface 32 of the chrome to obtain the brightest image of region 302. At the focus position E, it is impossible to focus again, and an image of darkness is obtained.

As a result of the image acquisition processing by the first image acquisition control unit 62, the image having the highest brightness among the respective focus positions A to E shown in Fig. 14 is selected, and finally stored in the memory 66. Further, the position coordinate data in the Z-axis direction at which the focus position at the time of capturing the last memory pixel is displayed corresponds to the pixel, and is stored in the memory 66.

Returning to Fig. 12, in step 3d, it is determined whether the image acquisition has reached the end focus position (E in Fig. 14), and if not, returns to step 3c, The focus is moved in a stepwise manner, and the image acquisition is continued. If it has arrived, the process proceeds to step 3e.

The control unit 60 performs image acquisition control by the second video acquisition control unit 63 as follows. That is, firstly, to step 3e, 65 is read from the memory corresponding to the deposition surface of the glass 32 and the light quantity setting of the configuration data OP _2, configuration data OP in accordance with light amount of the reading of ₂ to step 3f adjust the light amount of the light source 20 of . In this state, the second video acquisition control unit 63 performs the same processing as that of step 3c on the same conditions except for the light amount. The maximum brightness image and height image obtained here are IMG _MAX2 and IMGZ _{MAX2 respectively} .

Fig. 15 is a view showing an example of a conjugate focus image obtained at each of the focus positions A to E during the processing by the second image acquisition control unit 63. Compared with Fig. 14, although at the focus position B, the reflected light of the appropriate brightness above the noise level is obtained from the glass surface, at the focus position D, excessive brightness exceeding the dynamic range is formed, and the area 302 is infiltrated, which is not easy. Master the boundaries.

When the video acquisition control of the second video acquisition control unit 63 is completed, the control unit 60 finally activates the height calculation unit 64 in step 3i to perform the height calculation processing as follows. The height calculation unit 64 sets a normal upper limit value of the luminance value in advance. The height calculation unit 64 compares the high-intensity images IMG _MAX1 and IMG _{MAX2 for} each pixel, and selects a pixel having a large luminance value within a range not exceeding the upper limit value, and combines one height image IMGZ _MAX and maximum brightness image IMG _MAX . Then, based on the predetermined position (XY coordinate) of the combined height image IMGZ _MAX , the height of the top surface 31 of the chrome and the vapor deposition surface 32 of the glass are selected, and the difference is calculated.

In addition, in the actual measurement, the driving portion 50 is driven to make the conjugate focal length The width of the focus position of the micromirror 10 in the Z-axis direction is related to the half-value width of the IZ curve (the curve when the vertical axis is the brightness and the horizontal axis is the Z-axis coordinate). When the moving width is too large, the correct measurement cannot be performed. . Therefore, in order to measure the predetermined Z scan range in a short time, it is only necessary to increase the brightness, maintain a high S/N ratio, and perform camera shooting at a higher speed.

Since the conjugate focal length microscope with the microlens turntable used in this example has the characteristics of being brighter than the conventional conjugate focal length microscope, it is possible to perform high-magnification measurement which is conventionally impossible to observe, and the range of the amplitude can be measured by the selection of the objective lens.

(Third embodiment)

In the three-dimensional measuring apparatus according to the second embodiment of the present invention, the image combining and height calculating processing (step 3i) of the first embodiment is changed. That is, the maximum luminance images IMG _MAX1 and IMG _{MAX2 are not} compared according to the respective pixels, and the maximum luminance images IMG _MAX1 and IMG _MAX2 and the predetermined appropriate luminance upper limit value Th _HIGH and the lower limit value Th _{LOW are} compared as shown in Table 1. Here, the upper limit value Th _{HIGH is} set to be equal to or slightly smaller than the saturation level of the camera in the same manner as the upper limit value of the first embodiment, and the lower limit value Th _{LOW is} set to the vicinity of the class having an S/N ratio of about 0 dB. can. The premise is based on the light quantity setting data OP ₁ >OP ₂ .

In the image synthesis and height calculation processing, when the brightness value of the obtained maximum brightness image IMG _MAX1 is less than the lower limit value Th _LOW , the brightness value of the maximum brightness image IMG _MAX is 0 regardless of the maximum brightness image IMG _MAX2 . The height image IMGZ _MAX is the lowest value. When the brightness value of the maximum brightness image IMG _MAX1 is above the lower limit value Th _LOW and below the upper limit value Th _HING , the brightness value of the maximum brightness image IMG _MAX is the maximum brightness image IMG _MAX1 regardless of the maximum brightness image IMG _MAX2 . The height image IMGZ _MAX is the height image IMGZ _MAX1 . Moreover, when the brightness value of the maximum brightness image IMG _MAX2 is less than the upper limit value Th _HING , the brightness value of the maximum brightness image IMG _MAX is the maximum brightness image IMG _MAX2 , and the height image IMGZMAX is the height image IMGZ _MAX2 . When the brightness value of the maximum brightness image IMG _MAX1 is greater than the upper limit value Th _HING , and the brightness value of the maximum brightness image IMG _MAX2 is greater than the upper limit value Th _HING , the brightness value of the maximum brightness image IMG _MAX is the maximum value, and the height image IMGZ _MAX is The value is the highest value that is set.

That is, the light amount setting information OP _1> OP _2, the if the maximum brightness of the image IMG _MAX1 in the range of appropriate brightness, by unconditionally use S / N ratio is trustworthy the maximum brightness of the image IMG _MAX1 as the maximum brightness of the image IMG _MAX, but may be omitted Steps 3e~3g. Further, in the image composition and height calculation processing, by reading the memory access of the maximum brightness image IMG _MAX2 , higher speed processing can be performed.

Alternatively, the image is synthesized according to Table 2 below under any lighting conditions.

That is, in the image synthesis and height calculation processing, the luminance value of the obtained maximum luminance image IMG _MAX1 is less than the lower limit value Th _LOW , and the luminance value of the maximum luminance image IMGZ _MAX2 is less than the lower limit value Th _LOW or greater than the upper limit value. When Th _HING , the brightness value of the maximum brightness image IMG _MAX is 0, and the value of the height image IMGZ _MAX is the predetermined minimum value. Moreover, the height value of the maximum brightness image IMG _MAX1 is less than the lower limit value Th _LOW or greater than the upper limit value Th _HING , and the brightness value of the maximum brightness image IMG _MAX2 is greater than or equal to the lower limit value Th _LOW , and below the upper limit value Th _HING , Let the brightness value of the maximum brightness image IMG _MAX be the maximum brightness image IMG _MAX2 divided by the value of the light quantity setting data OP ₂ , and the height image IMGZ _MAX value is the height image IMGZ _MAX2 . Moreover, when the brightness value of the maximum brightness image IMG _MAX1 is greater than or equal to the lower limit value Th _LOW and below the upper limit value Th _HING , the brightness value of the maximum brightness image IMG _MAX is the maximum brightness image IMG _MAX1 regardless of the maximum brightness image IMG _MAX2 . In addition to the value of the light amount setting data OP ₁ , the height image IMGZ _MAX is the height image IMGZ _MAX1 . The brightness value of the maximum brightness image IMG _MAX1 is greater than the upper limit value Th _HING , and the brightness value of the maximum brightness image IMG _MAX2 is less than the lower limit value Th _LOW or greater than the upper limit value Th _HING , so that the brightness value of the large brightness image IMG _{MAX is} taken. For the maximum value, the height image IMGZ _MAX is the highest value.

At this time, when both the maximum brightness image IMG _MAX1 and the maximum brightness image IMG _MAX2 are outside the appropriate range, the comparison result with the maximum brightness image IMG _MAX1 takes precedence. The brightness value is divided by the light amount setting data OP ₁ , OP ₂ (preferably the amount of light), and can be combined into a line shape in any lighting condition.

Further, when the all-in-focus image IMG _MAX (and the height image IMGZ _MAX ) synthesized as described above is displayed, the 0 or the maximum value may be displayed differently from other values or aspects. An example is to assign a display color that is significantly different from other values to 0 and the maximum value, or a light-dark display or a hatched display. By thus making the display aspect different, the user can easily know that the light amount setting data OP ₁ and OP ₂ are both inappropriate.

Further, the present invention is not limited to the above embodiments. For example, in each of the above embodiments, the control unit 60 adjusts the amount of light of the light source 20 and performs height measurement. When the user of the three-dimensional measuring device adjusts the amount of light of the light source 20, the same can be applied.

Further, in each of the above embodiments, the image data captured by the camera 40 is converted by the first and second image acquisition control units 62 and 63 to select only the maximum brightness among the images obtained at the respective focus positions. The example in which the height is calculated after the image of the pixel is described is not limited to this method. For example, the first and second image acquisition control units 62 and 63 store the conjugate focus image of the conjugate focus positions A to E together with the conjugate focus position in the memory 66. Then, the height calculation unit 64 reads the focus position of the conjugate focal point image of the pixel including the maximum luminance, and when the height is measured based on the conjugate focus position, the same can be applied.

Further, in each of the above embodiments, the sample 30 is composed of two measurement targets, and the light source 20 is described by the light amount setting data OP ₁ and the light amount setting data OP ₂ , and the measurement amount of the sample is 2 One or more of them may be used, and the amount of light of the light source may be two or more and variable, and the same may be applied.

In the implementation stage of the present invention, the measurement object is deformed and embodied without departing from the scope of the gist. Various inventions can be formed by appropriate combinations of the plurality of measurement objects disclosed in the above embodiments. For example, several measurement objects can also be deleted from all measurement objects displayed in the embodiment. Furthermore, it is also possible to appropriately combine measurement objects of different embodiments.

Industrial availability

Each of the above embodiments is an example of a reflective illumination type, and the through illumination type can also be applied in the same manner, or can be used for viewing the fluorescent light as excitation light. That is, the present invention can also exert an advantageous effect when a sample in which a portion of the transmittance of almost 100% is mixed with a portion of almost 0% is measured. The present invention is not limited to use in an industrial conjugated focus microscope, and can also be used in various microscopes such as medical use (biological use).

1‧‧‧ images

2‧‧‧ images

10‧‧‧ Confocal microscope

11‧‧‧ Objective lens

12‧‧‧ Conjugate Focus Scanner

20‧‧‧Light source

30‧‧‧sample

31‧‧‧Chromium

32‧‧‧ glass

40‧‧‧ camera

50‧‧‧ Drive Department

60‧‧‧Control Department

61‧‧‧Main Control Department

62‧‧‧1st image acquisition control unit

63‧‧‧2nd image acquisition control unit

64‧‧‧ Calculation Department

65‧‧‧ memory

66‧‧‧ memory

100‧‧‧Light source

101‧‧‧ imaging lens

102‧‧‧half mirror

103‧‧‧Niprik Rotating Image Disc

104‧‧‧ pinhole

105‧‧‧ objective lens

106‧‧‧The sample surface of the object to be measured

107‧‧‧ imaging lens

108‧‧‧Photographing surface

150‧‧‧ camera

151‧‧‧Microscope

152‧‧‧ Objective lens

153‧‧‧sample

154‧‧‧Sample table

155‧‧‧Y-axis drive unit

156‧‧‧X-axis drive unit

157‧‧‧linear scale

158‧‧‧Z-axis drive unit

159‧‧‧XYZ axis control department

160‧‧‧PC

161‧‧‧Light source

162‧‧‧Light source control department

163‧‧‧ Height Measurement Department

301‧‧‧Area

302‧‧‧Area

303‧‧‧Area

901‧‧‧chrome mask

901-1‧‧‧Image of the vaporized surface of the bottom chrome 901

902‧‧‧Photoresist film

902-1‧‧‧Image of the photoresist film 902

903‧‧‧Image of the taper of the photoresist film 902

Fig. 1 is a schematic view for explaining the basic principle of a conventional conjugate focal length microscope.

The second graph shows the change in the height direction of the sample.

The third graph shows the relationship between the change in the height direction of the sample and the brightness value.

Fig. 4 shows the relationship between the change in the height direction of the sample and the brightness value as a difference in dimming.

Fig. 5 is a schematic block diagram showing the structure of an embodiment of the height measuring device of the present invention.

Figure 6 is a flow chart for explaining one embodiment of the automatic dimming processing program of the present invention.

Figure 7 is a flow chart for explaining one embodiment of the automatic dimming processing program of the present invention.

Figure 8 is a flow chart for explaining one embodiment of the automatic dimming process of the present invention.

Fig. 9 is a schematic view for explaining the image and the brightness signal level when the pattern surface of the sample having the step is taken.

Fig. 10 is a structural view showing a three-dimensional measuring device according to an embodiment of the present invention.

Figure 11 is a block diagram showing the functional structure of the control unit of Figure 10.

Figure 12 is a flow chart showing the processing procedure of the control unit of Figure 11.

Fig. 13 is a flow chart showing the imaging control of the first and second video acquisition control units in Fig. 11.

Fig. 14 is a conjugate focus image of the first image acquisition control unit of the above embodiment.

Fig. 15 is a conjugate focus image of the second video acquisition control unit of the above embodiment.

Figure 16 is a perspective view and a cross-sectional view of a hypothetical sample.

Figure 17 is a height image, a cross-sectional view, and an all-focus image measured at the outer periphery of the sample shown in Figure 16 under the most appropriate illumination.

Figure 18 is the bottom of the sample shown in Figure 16 under the most appropriate illumination. The height image, section view and all-focus image of the measurement.

20‧‧‧Light source

40‧‧‧ camera

50‧‧‧ Drive Department

60‧‧‧Control Department

61‧‧‧Main Control Department

62‧‧‧1st image acquisition control unit

63‧‧‧2nd image acquisition control unit

64‧‧‧ Calculation Department

65‧‧‧ memory

66‧‧‧ memory

Claims (3)

A three-dimensional measuring device comprising: a conjugate focal length microscope for magnifying an optical image of a sample having first and second measurement target portions having different reflectances; and a camera for taking a magnification of the conjugate focal length microscope After the optical image of the sample is output, the image data is output; the light quantity variable light source is configured to irradiate the sample with the light for photographing; and the driving mechanism may be the conjugate focal length microscope with respect to the sample. The focus position is changed in the direction of the optical axis thereof; and the control unit is connected to the camera, the light source, and the driving mechanism; and the control unit has a memory, and the memory display corresponds to the first and The light amount setting information of the first and second light amounts set in advance in the second measurement target portion; the first image acquisition control means sets the light emission amount of the light source based on the first light amount setting data stored in the memory, In this state, the focus position of the conjugate focal length lens relative to the sample is changed by the driving mechanism while the camera is photographed before the camera. The optical image of the sample is obtained by the image capturing device; the second image capturing control means sets the amount of light emitted by the light source according to the second light amount setting data stored in the memory, and in this state, The driving mechanism changes the optical position of the sample with the camera according to the focus position of the conjugate focal length microscope of the sample, and obtains the imaged image by the camera; and the calculation mechanism is based on the first and the first 2 image acquisition control mechanism The captured image is selected from a pixel region in which the luminance value is included in a preset maximum range, and the focus position of the conjugate focal microscope is obtained when the luminance value of the selected pixel region is within the aforementioned wide range. The standard calculates the height of the first and second measurement target portions. A height measuring device for controlling a conjugate focal length microscope for amplifying a sample, a light source for irradiating the sample, a control portion for adjusting the amount of light of the light source, a Z-axis driving portion for driving the Z-axis to change the focal height, and a conjugate focal length microscope The image camera and the measuring device, and the height of the sample is measured from the image captured by the camera, and is characterized by having a linear scale, and the control unit includes: a setting mechanism for setting a region for performing dimming and measuring the height. The Z-axis range, and the target upper limit value and the target lower limit value for adjusting the light amount; the height measurement program mechanism determines the height of one image; and the dimming program mechanism is before executing the height measurement program mechanism. Determining whether the parameter is within a range of the target upper limit value and the target lower limit value by using a peak value or a representative value of the preset image area as a parameter of the dimming, and determining the most suitable light quantity value; The obtaining means obtains the peak value or representative value of the brightness value of the previous image of the region where the dimming is performed; and the lowering mechanism determines that the peak value is obtained Or whether the peak value or the representative value of the brightness value of the previous image obtained by the obtaining means of the representative value is greater than the target upper limit value, and when the peak value or the representative value of the brightness value of the previous image is greater than the target upper limit value, Lowering the above upper limit target range by a predetermined value; and The improvement mechanism determines whether the peak value or the representative value of the brightness value of the previous image obtained by the acquiring unit that obtains the peak value or the representative value is greater than the target lower limit value, and the peak value or the representative value of the brightness value of the previous image When the target lower limit value is smaller than the target lower limit value, the control unit changes the focus height by the Z-axis drive unit, thereby reading the linear scale data and the camera. The image compares the brightness value of the previous image, and records the pixel with higher brightness value and its Z coordinate. The height measuring device of claim 2, wherein the control unit performs the following mechanism: the height measuring program mechanism; and obtaining the brightness of the previous image in the region where the dimming is performed, before executing the automatic dimming program mechanism a mechanism for obtaining a peak value or a representative value; determining whether the peak value or the representative value of the brightness value of the previous image obtained by the acquiring unit that obtains the peak value or the representative value is greater than the target upper limit value, when the foregoing And when the peak value or the representative value of the brightness value of the image is greater than the target upper limit value, the upper limit target range is lowered by a predetermined value; and the improvement mechanism determines the previous image obtained by the acquiring unit that obtains the peak value or the representative value Whether the peak value or the representative value of the brightness value is greater than the target lower limit value, and when the peak value or the representative value of the brightness value of the previous image is smaller than the target lower limit value, the lower limit target range is increased by a predetermined value.