JPH0961720A - Confocal scanning type optical microscope and measuring method using the microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always perform a correct shape measurement even for a sample whose shape of an observation surface continuously changes and whose reflectivity of the observation surface is largely different depending on the shapes by surely detecting a boundary part of an observation sample. SOLUTION: In a confocal scanning type optical microscope provided with a photodetector 13 receiving the reflected light by a sample 8 and outputting a detection signal corresponding to the intensity of the received light, and a gain adjusting circuit 33 varying the signal level of the detection signal from the photodetector 13, a level discriminating circuit 31 judging whether the signal level of the detection signal of the photodetector 13 is in a previously set proper range or not, and a CPU 30 performing an adjustment so that the signal level becomes to be in the previously set proper range by variably adjusting the gain of the gain adjusting circuit 33 when the signal level of the detection signal is judged to be out of the proper range by the level discriminating circuit 31 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a confocal scanning optical microscope used for measuring surface information of an observation sample.

[0002]

2. Description of the Related Art Conventionally, a point light source illuminates the surface of an observation sample in a point shape, and the transmitted light or reflected light from the illuminated sample surface is condensed again in a point shape to have a pinhole opening. There has been a confocal scanning optical microscope in which an image is formed on a detector and the density information of the image is obtained by this detector.

FIG. 8A is a schematic configuration diagram of a general confocal scanning optical microscope. In the figure, a point light source 91
The point-like light emitted from the laser beam passes through the half mirror 92 and is then point-formed into an image on the surface of the observation sample 94 by the objective lens 93 whose aberration is corrected.

Then, the light reflected by the sample 94 of the point-like illumination passes through the objective lens 93 again and is reflected by the half mirror 92 to be condensed. A pinhole 95 is provided at this light collecting position.
The reflected light that has passed through 5 is detected by the photodetector 96.

Such point illumination is performed over the entire measurement area of the surface of the observation sample 94, and the detection signal of the reflected light by the photodetector 96 is two-dimensionally scanned, such as raster scanning, to obtain the surface of the observation sample 94. The two-dimensional image of is obtained.

By the way, the surface of the observation sample 94 is not necessarily flat over the entire surface, and there is a surface at a position deviated from the condensing position of the objective lens 93 as shown by L in FIG. 8A. The reflected light reflected from such a surface L is
The light is not focused on the pinhole 95. Therefore,
Such reflected light cannot pass through the pinhole 95 and is therefore not detected by the photodetector 96. That is, the confocal scanning optical microscope can measure only the optical image of the sample surface existing at the focusing position of the objective lens 93, that is, the focusing position.

Next, for example, when observing a sample 94 'having a plurality of observation planes A, B and C having different heights with a confocal scanning optical microscope as shown in FIG. When focused, the optical images on the other observation planes B and C are completely invisible. Therefore, it is impossible to simultaneously observe the focused images on all the observation planes A, B, and C.

However, for example, the observation planes A, B, and C are sequentially focused, and the focused images are sequentially stored in the image memory,
By synthesizing these focused images by arithmetic processing, it is possible to obtain an observed image focused on all the observation planes A, B, and C. It should be noted that the combination of the focused observation images is actually performed by holding the value that maximizes the brightness for each pixel.

Regarding the method of observing the sample surface described above, for example, "THEORY AND PRACTICE"
OF SCANNING OPTICAL MICRO
SCOPY "(pages 126-130).
That is, in a state where the focused light is irradiated to one point on the sample surface, first, the focused light is scanned in the optical axis direction (Z direction), and a position (Z position) where the brightness is maximum is detected during the scanning. save. Next, by moving the focused light in the X direction, the initial irradiation point of the focused light is positioned at the next point on the sample surface, and in this state, the focused light is scanned in the Z direction, and during the scanning. The position where the brightness is maximum (Z position) is detected and saved.

Similarly, each time the position of the initial irradiation point of the focused light is moved stepwise in the X and Y directions, the focused light is scanned in the Z direction, and the maximum value of the brightness detected by these scannings is determined. Save each. Thus, the surface information of the sample is measured based on the change in brightness.

However, when the above-mentioned observation is performed, the following problems occur in the conventional confocal scanning optical microscope. That is, the detection signal obtained by the photodetector is amplified in the variable gain amplifier circuit so that the signal level becomes the optimum value. In this case, there is no problem if the reflectance of the sample in the observation or measurement range is constant.
However, if there are a plurality of regions having different reflectances in the observation or measurement range of the sample, an accurate detection signal cannot be obtained.

Therefore, in Japanese Patent Application No. 7-35474, when the sample has an observation surface whose reflectance greatly differs depending on the height, the reflectance is changed by changing the signal level in the middle of the measurement range. It can be observed at multiple sites.

[0013]

However, a sample having a plurality of portions having different reflectances, which is assumed by Japanese Patent Application No. 7-35474, is a sample as shown in FIG. 8 (b), for example. It is a step-shaped sample, the A side is a glass surface,
This is dealt with by setting the position where the signal level is changed to a vertical portion between the A surface and the B surface, or between the B surface and the C surface, such that the B surface is a mirror surface.

Therefore, in the case of a sample in which the flat surface portion and the sloped surface portion are continuous, such as a shape having a V-shaped groove,
There is a problem in that the signal level cannot be reliably changed at the boundary between the flat surface portion and the sloped surface portion, and accurate observation and measurement cannot be performed at the boundary portion.

The present invention has been made in view of the above-mentioned circumstances, and is an observation sample in which the shape of the observation surface continuously changes and the reflectance of the observation surface greatly differs depending on the shape. However, the confocal scanning optical microscope and this microscope that can always accurately measure the shape by accurately detecting the boundary part where the shape changes and setting the signal level to an appropriate value from that position. The purpose is to provide the measurement method used.

[0016]

According to the first aspect of the present invention,
An objective optical system for irradiating a sample with focused light, a two-dimensional scanning means for moving and scanning the focused light and the sample relatively in a two-dimensional direction, a focus position of the objective optical system and a position of the sample Optical axis scanning means for relatively moving and scanning in the optical axis direction, light detecting means for receiving the reflected light of the focused light by the sample and outputting a detection signal according to the received light intensity, and the light detecting means. In the confocal scanning optical microscope provided with a variable gain type level varying means for varying the signal level of the detection signal output from the above, the signal level of the detection signal from the photodetection means falls within a preset proper range. Determining means for determining whether or not there is any, and when the determining means determines that the signal level of the detection signal is out of a preset proper range, the gain of the variable gain type level varying means is variably controlled. The belief Levels are such that and a gain control means for adjusting to be within a proper range that is set in advance.

As a result, according to the first aspect of the present invention,
The judging means judges from time to time whether or not the signal level of the detection signal from the light detecting means is within a preset proper range. When the determination means determines that the signal level of the detection signal is out of the preset proper range, the gain control means variably controls the gain of the variable gain type level variation means to obtain the signal level. Will be adjusted to fall within a preset proper range. Therefore, even in the case of an observation sample in which the shape of the observation surface changes continuously, and the reflectance of the observation surface greatly differs depending on the shape, it is possible to reliably detect the boundary portion where the shape changes,
By setting the signal level to an appropriate value from that position, it is possible to realize a confocal scanning optical microscope capable of always performing accurate shape measurement.

According to a second aspect of the present invention, an objective optical system for irradiating a sample with focused light, a two-dimensional scanning means for moving the focused light and the sample relatively in a two-dimensional direction, and the objective. Optical axis scanning means for relatively moving and scanning the focal point position of the optical system and the position of the sample in the optical axis direction, and the reflected light of the focused light of the sample is received and a detection signal corresponding to the received light intensity is received. The surface of the sample is measured by using a confocal scanning optical microscope equipped with a light detecting means for outputting and a variable gain type level varying means for varying the signal level of the detection signal outputted from the light detecting means. At this time, a determination step of determining whether or not the signal level of the detection signal from the photodetection means is within a preset proper range, and an appropriate range in which the signal level of the detection signal is preset by this determination step. Outside The gain of the variable gain type level varying means variably controlled to have to have a gain control step of adjusting so that the proper range the signal level is set in advance when it is determined.

As a result, whether or not the signal level of the detection signal from the light detecting means is within the preset proper range is determined at any time in the determination step. When it is determined in this determination step that the signal level of the detection signal is out of the preset proper range, the process proceeds to the gain control step to variably control the gain of the variable gain type level varying means, The signal level is adjusted so as to be within a preset proper range. Therefore, even in the case of an observation sample in which the shape of the observation surface changes continuously and the reflectance of the observation surface varies greatly depending on the shape, the boundary portion where the shape changes can be reliably detected and its position Therefore, by setting the signal level to an appropriate value, accurate shape measurement can always be performed.

[0020]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the system configuration of the entire confocal scanning optical microscope according to an embodiment of the present invention. In the figure, 1 is a confocal scanning optical microscope main body, and 2 in the microscope main body 1 is a laser light source which is a light source of scanning light. The laser light as the spot light generated by the laser light source 2 is totally reflected by the mirror 3 and is sent to the two-dimensional scanning mechanism 5 after passing through the half mirror 4.

Here, the intensity of the laser beam can be adjusted by the laser power source unit 26, which is the power source of the laser light source 2, and the ND filter 27 disposed between the laser light source 2 and the mirror 3 is rotated, It can also be adjusted by changing the amount of laser light transmission.

The ND filter 27, whose detailed configuration will be described later, is rotatably driven by a motor 28 to variably control the amount of laser light transmission, and the motor 28 follows a drive signal from a motor drive circuit 29. Is. These adjustments are sent to the image processing unit 14 in response to a command from the computer 17, and the image processing unit 1
This is done by sending a control signal to the laser power supply unit 26 and the motor drive circuit 29 by the CPU 30 in the CPU 4.

The two-dimensional scanning mechanism 5 has, for example, a galvano mirror for X-axis direction scanning and a galvano mirror for Y-axis direction scanning, and the XY scanning control unit 1 to be described later.
Under the control of 6, the two galvanometer mirrors are swung in the X-axis direction and the Y-axis direction to perform XY scanning of the spot light similarly to the raster scanning in the television system. The spot light is applied to the sample 8 mounted on the fine movement stage 9 by the objective lens 7 via the revolver 6.

That is, the revolver 6 holds a plurality of objective lenses 7 having different magnifications, and the fine movement stage 9 holds the sample 8. The fine movement stage 9 is provided on the coarse movement stage 10.

Among the plurality of objective lenses 7 held by the revolver 6, a person having a desired magnification is switched by rotating the revolver 6 and is set in the observation optical path of the microscope.
The spot light from the two-dimensional scanning mechanism 5 is transmitted to the sample 8 on the fine movement stage 9 via the objective lens 7 set in this position.
Irradiation can be performed while performing dimension scanning.

The reflected light by this irradiation returns to the two-dimensional scanning mechanism 5 through the objective lens 7 and is returned from the two-dimensional scanning mechanism 5 to the half mirror 4. The half mirror 4 is provided on the emission optical path of the laser light source 2 with respect to the two-dimensional scanning mechanism 5, and is for guiding the reflected light from the sample 8 obtained through the two-dimensional scanning mechanism 5 to the detection system. The reflected light from the sample 8 obtained in 4 is condensed by the lens 11 and sent to the photodetector 13 via the pinhole plate 12 having an opening of a predetermined diameter.

That is, the photodetector 13 is provided with the lens 11 and the pinhole plate 12 at the focal position of the lens 11 on its light receiving surface, and the light obtained through the pinhole plate 12 is It is converted into an analog electric signal (luminance signal) corresponding to the amount of light, and the level determination circuit 31 in the image processing unit 14 and the CPU 30 to the D / A conversion circuit 3
7, an offset adjustment circuit 32 in which an offset value is set, and a CPU 30 to D / A conversion circuit 36.
The gain value is set via the gain adjusting circuit 33, and the A / D conversion circuit 34 converts the data into digital data in synchronization with the sampling clock from the counter circuit 38, and then sends the digital data to the image memory 14a.

The image processing unit 14 has two image memories 14a and 14b, and each of the image memories 14a and 14b has a storage capacity for one frame. Here, the storage capacity of one frame is, for example, 512 pixels × 512 pixels × 8 bits (256 gradations / pixel).

Of the two image memories 14a and 14b, the image memory 14a stores the brightness information of the reflected light obtained by the photodetector 13 in the pixel position corresponding to the current XY scanning position of the spot light. The image signal of the sample 8 is stored by storing as 8-bit data in synchronization with the write timing signal from the counter circuit 38.

When the luminance information of this time has a larger value (brightness) than the luminance information of the previous same scanning position, this image memory 14a is updated and held as the image information of this scanning position. Thus, it is possible to add images having different height positions.

Further, the other image memory 14b has a Z position at the pixel position corresponding to the current XY scanning position of the spot light.
The information on the moving direction, specifically, the number of times the revolver 6 has moved from the Z moving circuit 15 is counted, and the count value is counted.
The data is stored in synchronization with the write timing signal from 8.

In this case, when the image processing unit 14 updates and holds the brightness information in the image memory 14a, that is, by referring to the image data in the image memory 14a, this time, rather than the brightness information at that position last time, this time. When the luminance information of 1 is larger (brighter), the image memory 14b has a function of updating the value of the number of times as data and storing and holding the data.

In this way, when the image memory 14b has information indicating the maximum brightness at each pixel position, the revolver movement count value indicates information in the Z scanning direction, that is, the height position. It is stored as information.

The Z moving circuit 15 is a computer 17
Alternatively, the revolver 6 is controlled by the image processing unit 14 to move the revolver 6 in the height direction, that is, Z along the observation optical path axis.
A circuit for performing control so as to move in the axial direction in units of the reference width, a count function of counting position information each time the revolver 6 is moved in the unit of the reference width, and a function of sending the count value to the image memory 14b. And have.

However, the image processing unit 14 and Z
XY for controlling the moving circuit 15 and the two-dimensional scanning mechanism 5
A computer 17 is provided to integrally control the scan control unit 16.

In addition to the overall control of the XY scanning control unit 16, the Z movement circuit 15 and the image processing unit 14, the computer 17 performs overall control and processing such as storage, reproduction and editing of image data. It plays a central role in displaying necessary information and images on the monitor display 18.

Further, a television optical system is prepared for roughly focusing on the sample 8 mounted on the fine movement stage 9 when the sample 8 is measured. This is used in consideration of the point that it is slightly difficult to use because the focal depth is extremely shallow when focusing is performed on a confocal image obtained by laser scanning.

That is, the light generated by the white light source 19 is totally reflected by the half mirror 21 after passing through the lens 20, and is inserted into the laser optical path between the two-dimensional scanning mechanism 5 and the revolver 6 through the lens 22. The sample 8 is reflected by the mirror 23 and is radiated to the sample 8 mounted and supported on the fine movement stage 9 by the objective lens 7 via the revolver 6.

The light reflected by this irradiation passes through the objective lens 7, is reflected by the mirror 23, passes through the lens 22, and then passes through the half mirror 21, and the lens 2
An image is formed on the television camera 25 by the camera 4.

The sample image taken by the television camera 25 is displayed on the monitor display 18,
The observer moves the coarse movement stage 10 while looking at the image on the monitor display 18 to focus. At this time, the observer can know the approximate shape and in-focus position of the sample 8.

Next, as the operation of the above-described embodiment, details of the case where the shape of the sample 8 is measured by the laser light generated by the laser light source 2 will be described. However, when measuring the shape of the sample 8, even if there is a large difference in reflectance due to the shape of the sample 8, the level of the luminance signal should be changed according to the change in reflectance so that the signal can be reliably captured. Need to be adjusted. Here, the present invention is characterized by
A signal adjusting function for detecting a change in reflectance due to a change in shape, which will be described later, and setting the level of the luminance signal in an appropriate range is used.

In the following description, the sample 8 having a V-shaped groove as shown in FIG. 2 is used. That is, the sample 8 shown in FIG. 2 has two plane portions A, A and a pair of slope portions B, B sandwiched between these plane portions A, A.

At the beginning of the operation, first, the flat surface portion A and the sloped surface portion B are
Examine its signal level so that it can be imaged. The output of the laser light source 2 and the value of the ND filter 27 prior to scanning,
Gain and offset adjustment circuit 3 in the gain adjustment circuit 33
The offset value of 2 is a preset value (default value). Laser scanning is started in this state, and the focus position is aligned with the plane portion A.

FIG. 3 shows the level of the luminance signal of the sample 8 in the X direction. FIG. 3A exemplifies the level of the luminance signal at the default value, and the hatched range is a preset proper range (the same applies hereinafter).
In this state, it can be seen that the brightness signals of both the flat surface portion A and the sloped surface portion B are out of the proper range, and in particular, the sloped surface portion B is not at the in-focus position, so that the brightness signal is at the zero level.

When the luminance signal with the default value as shown in FIG. 3A is obtained, the observer changes the gain value so that the luminance signal of the flat surface portion A is within the proper range. . The computer 17 sends a message to the image processing unit 14 to change the gain value.

The CPU 30 of the image processing unit 14 converts the instructed numerical data into an analog value by the D / A conversion circuit 36, and then supplies it to the gain adjusting circuit 33 to set it as a new gain value.

Therefore, the obtained luminance signal is amplified by the new gain value. FIG. 3B shows the luminance signal with the new gain value α, and it can be seen that the plane portion A is within the proper range.

Next, the revolver 6 is moved in the Z direction by the Z moving circuit 15 while keeping the gain value in the gain adjusting circuit 33 at α, and the focus position is adjusted to the slope B of the sample 8.
Since the laser light is reflected in the oblique direction on the slope portion B,
The amount returned to the photodetector 13 is extremely smaller than that in the flat surface portion A. Therefore, even if the gain value in the gain adjusting circuit 33 is α, the level of the luminance signal may not fall within the proper range, and this depends on the inclination of the slope portion B.
Here, it is assumed that the inclination is steep, and it is assumed that a luminance signal having a level as shown in FIG. 3C can be obtained, for example. At this time, the luminance signal of the plane portion A is at the zero level because the plane portion A is out of the in-focus position due to the movement of the revolver 6.

Therefore, in order to keep the luminance signal of the slope B within the proper range, a gain β different from the above α is set in the gain adjusting circuit 33 in the same manner as above. Here, "α <
β ”, and FIG. 3D shows the level of the luminance signal obtained when the gain β is set.

As a matter of course, if the focus position is adjusted to the plane portion A with the gain value set to β, the level of the luminance signal of the plane portion A greatly exceeds the appropriate range as shown in FIG. 3 (e). Result in a saturation level, which causes inconvenience in measurement. Therefore, the boundary between the flat surface portion A and the sloped surface portion B is surely detected, and the gain is changed from α to β.
Or you have to switch from β to α.

Since the optimum gain values of the flat surface portion A and the sloped surface portion B are obtained as described above, the measurement range is set next. The measurement range is set by utilizing the phenomenon that the luminance signal becomes zero level when the sample 8 deviates from the in-focus position as described above. At the beginning, the position where the plane portion A is in the in-focus position is set. The revolver 6 is moved in the upward direction, that is, the objective lens 7 and the sample 8 are separated from each other.

Then, the plane portion A also moves out of the in-focus position, so that the luminance signal gradually decreases and finally reaches the zero level. When this luminance signal becomes zero level,
The image of the sample 8 is not displayed on the monitor display 18 and becomes black. Therefore, the observer can determine that this position is the upper limit of the measurement range.

The lower limit position is set by moving the revolver 6 downward,
That is, the objective lens 7 and the sample 8 may be moved toward each other to find a position where the image on the slope B disappears. When the setting of the measurement range is completed, it is determined how fine the range is, that is, the resolution. The relationship between the measurement range, resolution, and number of movements is as follows. That is, measurement range = resolution × number of movements For example, when measuring a measurement range of 100 μm with a resolution of 1 μm, the revolver 6 is moved 100 times in the Z direction.

As described above, the parameters required for measurement can be obtained. In order to actually start the measurement, the software for setting the parameters as shown in FIG. 4 is prepared and the above-mentioned FIG.
Input the numerical values of the above parameters according to the screen as shown in. It should be noted that this numerical value input can be input individually when the numerical value of each parameter is known.

When the parameter setting is completed as described above, the measurement is subsequently started. That is, at the start of measurement, the computer 17 issues a measurement start command to the image processing unit 14 and the Z movement circuit 15. The Z movement circuit 15 moves the revolver 6 in the Z direction so that the objective lens 7 is located at the upper limit of the measurement range. Further, from the image processing unit 14, a signal which is a basis of the XY scanning drive signal is output from the counter circuit 38 and given to the XY scanning control unit 16.

From the counter circuit 38, the XY
In addition to signals related to XY scanning to the scanning control unit 16, a sampling clock for the above-mentioned A / D conversion circuit 34 for converting a luminance signal into a digital value in synchronization with XY scanning, and writing timing to the image memories 14a and 14b. A signal, a signal for moving the revolver 6 with respect to the Z moving circuit 15 at a resolution (reference unit amount) set by a parameter, and the like are output each time XY scanning is completed.

As shown in FIG. 5, XY scanning and movement in the Z direction are performed with the gain value α from the upper limit of the measurement range.
When the movement is completed several times, the in-focus position of the objective lens 7 coincides with the flat surface portion A of the sample 8. X at this position
When the Y scanning ends, the focus position moves by the reference unit amount and moves to the slope portion B.

When the focus position of the objective lens 7 is moved to the slope B while the gain value α remains the same, the level of the obtained luminance signal is out of the proper range as shown in FIG. 3 (c). This phenomenon is detected by the level determination circuit 31.

That is, the level judging circuit 31 is composed of a comparator, and is a circuit for judging whether or not the level of the input signal, here the luminance signal, is higher than the preset reference signal level. Two are used, one is used to detect the upper limit of the proper range and the other is used to detect the lower limit of the proper range. As a matter of course, the reference signal used for these two comparators is the CP
It can be freely set by U30.

In this way, the fact that the state of the observation surface has changed is transmitted from the level determination circuit 31 to the CPU 30, so that the CPU 30 changes the gain value from α to β. Then, at the slope B, the image is captured with the gain value β until the focus position of the objective lens 7 reaches the lower limit position of the measurement range.

After that, the measurement ends when the focus position of the objective lens 7 reaches the lower limit position of the measurement range. As described above, the level determination circuit 31 detects that the state of the observation surface has changed by utilizing the fact that the level of the luminance signal is out of the proper range. However, at the position in the Z-axis direction immediately after the start of measurement, the plane portion A is apart from the in-focus position of the objective lens 7, and the level of the luminance signal at this position is also outside the proper range. The gain value will be changed from α to β at the position.

In order to avoid such a malfunction, the level judgment circuit 31 is provided with a condition that the level judgment is started for the luminance signal once it has entered the proper range.
Although the case where the gain value is changed has been described in the operation of the above-described embodiment, the same operation is performed for the offset position, the ND filter value, and the laser output value, as shown in FIG.

Of these, as shown in FIG. 6 (a), the offset value has a large change in the entire level of the luminance signal, that is, the DC component, and a change within a minute time, that is, the AC component is small. This is effective when you want to increase only the AC component.

This is because, for example, if the gain value is increased in the state shown in FIG. 6 (a), the DC component is larger and the saturation level is easily reached. By subtracting the components and then increasing the gain value, only the AC component can be amplified as shown in FIG. 6 (b).

Further, the larger the light amount of the laser light applied to the sample 8, the larger the light amount of the reflected light returning to the photodetector 13. For example, the sample 8 having the shape shown in FIG.
However, it is possible that the level of the luminance signal of the slope B falls within the appropriate range even though the gain value is the minimum because the irradiation amount of laser light is large.

In such a state, when the focus position of the objective lens 7 reaches the plane portion A, the level of the luminance signal of the plane portion A is saturated. However, since the gain value is the minimum, it cannot be further reduced.

The parameters of the ND filter value and the laser output value are prepared to be variably set in such a state. Both have a function of adjusting the light amount of the laser light with which the sample 8 is irradiated. With this function, the light amount on the plane portion A is adjusted so that the level of the luminance signal is adjusted even if the gain is the minimum value. It is possible to put it in the proper range.

Specifically, the level output value is adjusted by the CPU 30 of the image processing unit 14 by directly controlling the laser power supply unit 26. On the other hand, the ND filter value is
As shown in FIG. 7A, the ND filter 27a that continuously changes its transmittance on the same circumference, or a plurality of ND filters having different transmittances as shown in FIG. ND1 "to" ND5 ") are arranged on the same circumference, and the ND filter 27b is used by the motor 28 under the control of the CPU 30 to selectively move the laser beam in the laser optical path. By inserting it, as a result, the laser light amount is changed.

In the above embodiment, the objective lens 7
The movement of the revolver 6 in the Z-axis direction for changing the relative position of the sample 8 and the sample 8 was performed. On the contrary, the position of the revolver 6 was fixed and the fine movement stage 9
Alternatively, the coarse movement stage 10 may be moved in the Z-axis direction.

Further, it is not necessary to set all the gain value, offset, ND filter value and laser output value of the luminance signal, and only the necessary values may be set. You may make it select and configure only what is required.

Further, the shape of the sample 8 can be dealt with as long as the shape of the observation surface continuously changes, and it is needless to say that the shape is not limited to the shape shown in FIG. Even if there are two or more portions where the reflectance greatly changes due to a change in shape, it is possible to deal with the same problem by setting the number of regions shown in FIGS. 4 and 5 according to the number.

[0072]

As described above, according to the present invention, even with an observation sample in which the shape of the observation surface changes continuously and the reflectance of the observation surface varies greatly depending on the shape, A confocal scanning optical microscope that can always perform accurate shape measurement by reliably detecting the boundary portion where the shape changes and setting the signal level to an appropriate value from that position, and measurement using this microscope A method can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a system configuration of an entire confocal scanning optical microscope according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating the shape of the sample of FIG.

FIG. 3 is a diagram exemplifying a change in level of a luminance signal according to the same embodiment.

FIG. 4 is a view showing an example of a parameter setting screen according to the same embodiment.

FIG. 5 is a diagram illustrating a focusing operation according to the same embodiment.

FIG. 6 is a diagram exemplifying a change in a luminance signal according to the same embodiment, which is caused by an offset value.

FIG. 7 is a diagram illustrating a specific configuration of the ND filter of FIG.

FIG. 8 is a schematic configuration diagram of a general confocal scanning optical microscope and a diagram showing an example of a sample.

[Explanation of symbols]

 1 ... Microscope main body 2 ... Laser light source 3, 23 ... Mirror 4, 21, 92 ... Half mirror 5 ... Two-dimensional scanning mechanism 6 ... Revolver 7, 93 ... Objective lens 8, 94 ... Observation sample 9 ... Fine movement stage 0 ... Coarse movement Stage 11, 20, 22, 24 ... Lens 12 ... Pinhole plate 13, 96 ... Photodetector 14 ... Image processing unit 14a, 14b ... Image memory 15 ... Z moving circuit 16 ... XY scanning control unit 17 ... Computer 18 ... Monitor Display 19 ... White light source 25 ... Television camera (TVC) 26 ... Laser power supply unit 27, 27a, 27b ... ND filter 28 ... Motor 29 ... Motor drive circuit 30 ... CPU 31 ... Level determination circuit 32 ... Offset adjustment circuit 33 ... Gain adjustment Circuit 34 ... A / D conversion circuit 36, 37 ... D / A conversion circuit 38 ... Counter circuit 1 ... point light source 95 ... pinhole

Claims (2)

[Claims] 1. An objective optical system for irradiating a sample with focused light, a two-dimensional scanning means for moving and scanning the focused light and the sample relatively in a two-dimensional direction, and a focus position of the objective optical system. Optical axis scanning means for moving and scanning the position of the sample relatively in the optical axis direction, and light detection means for receiving reflected light of the focused light by the sample and outputting a detection signal according to the received light intensity. In a confocal scanning optical microscope equipped with a variable gain type level varying means for varying the signal level of the detection signal output from the light detecting means, the signal level of the detection signal from the light detecting means is preset. And a gain of the variable gain type level varying means when the signal level of the detection signal is determined to be outside the preset proper range by the determining means. Allowed Control to confocal scanning optical microscope, characterized by comprising a gain control means for adjusting so that the proper range the signal level is set in advance. 2. An objective optical system for irradiating a sample with focused light, a two-dimensional scanning means for moving and scanning the focused light and the sample relatively in a two-dimensional direction, and a focus position of the objective optical system. Optical axis scanning means for moving and scanning the position of the sample relatively in the optical axis direction, and light detection means for receiving reflected light of the focused light by the sample and outputting a detection signal according to the received light intensity. When performing the surface measurement of the sample using a confocal scanning optical microscope equipped with a variable gain type level varying means for varying the signal level of the detection signal output from the light detecting means, the light detecting means is used. Judgment step for judging whether or not the signal level of the detection signal from is within a preset proper range, and this judgment step judges that the signal level of the detection signal is outside the preset proper range. In case above And a gain control step of variably controlling the gain of the variable gain type level varying means to adjust the signal level so as to be within a preset proper range. The measurement method used.