JP2007286284A - Confocal scanning type microscopic system and observation method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a confocal scanning type optical microscopic system capable of performing measurement without being influenced by a following condition, that is, when a level difference exists on the measurement object surface of a sample, when a part having different reflectance exists or when a transmission surface exists. <P>SOLUTION: The confocal scanning type optical microscopic system sets divided areas that are areas obtained by dividing an area that is the measurement object range of the sample into plurality, and a divided area observation range that is an observation range set corresponding to the divided area in an optical axis direction in terms of the divided area, and acquires representative pixel data that is pixel data as a representative out of the respective pixel data of a two-dimensional image acquired within the divided area observation range by displacing the sample in the divided area observation range by a relative position displacing means. The above-mentioned problem is solved by constructing an observation image based on the representative pixel data. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an apparatus for observing the height of a sample surface, and more particularly to a confocal scanning microscope apparatus that acquires height information.

  The confocal scanning microscope scans the sample surface with the light from the light source as a spot, and converts only the light that has passed through the confocal stop out of the reflected light from the sample surface into an electrical signal by a photodetector. Three-dimensional information on the sample surface can be obtained.

  In such a confocal scanning microscope, the amount of light detected when focused on the optical axis is maximized, and the amount of light is almost zero when it is out of focus. Accordingly, the sample height information can be obtained by two-dimensionally scanning the sample surface with the spot light while moving the sample surface at a predetermined pitch in the Z-axis direction.

In recent years, an infrared confocal scanning microscope that can obtain the height information of the internal structure by transmitting the sample with infrared light has been put into practical use.
Japanese Patent No. 3704387 JP-A-9-68413

  By the way, the sample surface is not necessarily flat throughout, and the reflectance often varies depending on the surface. For example, Patent Document 1 discloses that an image is acquired by providing a region, setting a gain value of a detector according to reflectance, and the like. In Patent Document 1, an attempt is made to perform measurement without being affected by the difference in reflectivity even when there are portions having different reflectivities on the measurement target surface.

  However, in this technique, the detection signal obtained at each capture height is used for height image construction regardless of the region, so the result of the region of interest influences the gain condition for another region. There is a possibility of receiving.

In addition, when the transparent film is observed or infrared light is observed, the upper surface and the lower surface of the transmission surface cannot be distinguished and imaged.
In view of the above circumstances, in the present invention, even when there is a step on the measurement target surface of the sample, when there is a portion with a different reflectance, or when there is a transmission surface, the sample is not affected by these. The present invention provides a confocal scanning optical microscope system and an observation method using the same.

  The confocal scanning microscope system according to the present invention includes a light source that emits light, a two-dimensional scanning unit that relatively scans a sample in a two-dimensional direction with irradiation light emitted from the light source, and the scanned light. An objective optical system for condensing the illumination light, and detecting the reflected light reflected by irradiating the sample with the illumination light condensed by the objective optical system, and outputting a detection signal corresponding to the detected intensity A light detection means, a two-dimensional image acquisition means for acquiring a two-dimensional image based on the detection signal output from the light detection means, and a relative position for relatively displacing the position of the sample with respect to the objective optical system Displacement means and division area related information storage in which information related to the division area observation range that is an observation range in the optical axis direction corresponding to the division area obtained by dividing the measurement target range of the sample into a plurality of areas is stored When the sample is displaced by the relative position displacement means in each divided region observation range, representative pixel data is acquired from each pixel data of the two-dimensional image acquired in the divided region observation range. It comprises a representative pixel data acquisition means and an observation image construction means for constructing an observation image based on the representative pixel data.

  In the confocal scanning microscope system, the representative pixel data acquisition unit converts pixel data having the maximum luminance among the pixel data of the two-dimensional image acquired within the divided region observation range to the representative pixel data. It is characterized by acquiring as.

  In the confocal scanning microscope system, when the sample is discretely displaced by the relative position displacement unit in each divided region observation range, the representative pixel data acquisition unit is acquired within the divided region observation range. For each pixel data of the plurality of two-dimensional images, a luminance value change curve is calculated based on pixel data including pixel data having the maximum luminance value, and the maximum value of the change curve is acquired as the representative pixel data It is characterized by doing.

The confocal scanning microscope system further includes light detection control means for controlling detection sensitivity of the light detection means in accordance with the respective divided regions.
The divided area related information storage means further stores the detection level of the light detection means for each divided area, and the light detection control means detects the detection level for each divided area from the divided area related information storage means. And the detection sensitivity of the light detection means is controlled.

In the confocal scanning microscope system, the light source, the objective optical system, and the light detection means are an infrared light source, an infrared optical system, and an infrared light detection device, respectively.
The representative pixel data includes at least a luminance value and position information in the optical axis direction.

  An observation method of a confocal scanning microscope system in which an observation image is displayed on a display device according to the present invention is a method in which a measurement target range of a sample displayed on the display device is divided into a plurality of regions, and the division in an optical axis direction is performed. A measurement range is set for each of the regions, and the relative position between the sample and the objective optical system of the confocal scanning microscope is changed in the optical axis direction, and illumination light focused by the sample objective optical system is 2 Luminance of each pixel based on the detection signal acquired within the set measurement range by obtaining a detection signal corresponding to the detection intensity by detecting reflected light that is irradiated and reflected on the sample by scanning in the dimension direction Of the information, representative pixel data having representative luminance information is acquired, and an observation image is constructed based on the representative pixel data.

  By using the present invention, even when there is a step on the measurement target surface of the sample, when there is a part with different reflectance, or when there is a transmission surface, measurement is performed without being affected by these. Can do.

  A confocal scanning microscope system according to an embodiment of the present invention includes a light source, a two-dimensional scanning unit, an objective optical system, a light detection unit, a two-dimensional image acquisition unit, a relative position displacement unit, and a divided region. An information storage unit, a representative pixel data acquisition unit, and an observation image construction unit are provided.

  A light source (for example, corresponding to the light source 1) emits light. A two-dimensional scanning unit (for example, corresponding to the two-dimensional scanning mechanism 3) relatively scans the sample with irradiation light irradiated from the light source in a two-dimensional direction. The objective optical system (for example, corresponding to the objective lens 7) collects the illumination light scanned by the two-dimensional scanning means.

  The light detecting means (for example, corresponding to the light detector 11) detects the reflected light reflected by irradiating the sample with the illumination light condensed by the objective optical system, and outputs a detection signal corresponding to the detected intensity. Output.

  A two-dimensional image acquisition unit (for example, corresponding to the computer 12) acquires a two-dimensional image based on the detection signal output from the light detection unit. Relative position displacement means (for example, corresponding to the Z revolver 6) relatively displaces the position of the sample with respect to the objective optical system.

  The divided region related information storage means (for example, corresponding to the region height range setting table 30) includes a divided region that is a region obtained by dividing the measurement target range of the sample into a plurality of regions, and the divided regions. The information regarding the divided area observation range which is the observation range related to the optical axis direction for the divided area set in this manner is stored.

  When representative pixel data acquisition means (for example, corresponding to the computer 12) displaces the sample in the measurement target range of the sample by the relative position displacement means, if the relative position falls within the respective divided area observation ranges, the division is performed. Representative pixel data (representative pixel data) is acquired from each pixel data (a plurality of pixel data indicated by the same two-dimensional coordinates) of a plurality of two-dimensional images acquired within the region observation range.

An observation image construction unit (for example, corresponding to the computer 12) constructs an observation image based on the representative pixel data.
By configuring in this way, even if there is a step on the measurement target surface of the sample, there is a part with different reflectance, or there is a transmission surface, each arbitrarily set in the optical axis direction Since a representative value of each pixel within the range can be obtained, an observation image from which noise components have been removed can be obtained.

  The representative pixel data can be obtained by various methods. For example, the representative pixel data acquisition unit can acquire pixel data having the maximum pixel value as representative pixel data among the pixel data of a plurality of two-dimensional images acquired within each divided region observation range. .

With this configuration, pixel data having the maximum brightness of each pixel within each range arbitrarily set in the optical axis direction can be obtained.
Further, the representative pixel data acquisition means calculates a luminance value change curve based on pixel data including pixel data having the maximum luminance value for each pixel data of a plurality of two-dimensional images acquired within the divided region observation range. The maximum value of the change curve can be calculated and acquired as the representative pixel data.

With this configuration, the interval between the movement steps in the direction of the optical axis can be increased, so that the time required for measurement can be shortened.
The confocal scanning microscope system further includes light detection control means (for example, corresponding to the computer 12) for controlling the detection sensitivity of the light detection means in accordance with the respective divided regions.

With this configuration, the gain of the light detection unit can be adjusted according to each divided region.
The divided area related information storage means further stores the detection level of the light detection means for each divided area, and the light detection control means acquires the detection level for each divided area from the divided area related information storage means, and The detection sensitivity of the detection means can be controlled.

With this configuration, the gain of the light detection unit can be set according to each divided region.
In this confocal scanning microscope system, an infrared light source, an infrared optical system, and an infrared light detection device may be used for the light source, the objective optical system, and the light detection unit, respectively.

With this configuration, when a silicon substrate is used as a sample, for example, a surface region of the silicon substrate and a surface region obtained by internal transmission can be obtained.
The representative pixel data includes at least a luminance value and position information in the optical axis direction.

  By configuring in this way, the relative distance between the representative pixel data can be obtained by acquiring the difference between the representative pixel data, so that the step of the sample can be easily obtained.

<First Embodiment>
In this embodiment, when there are steps on the measurement target surface of the sample, an observation region corresponding to each step and a range in the Z direction corresponding to the observation region are set, and the revolver is displaced to acquire a two-dimensional image. A microscope system that acquires the highest pixel value among the luminance values of each pixel in the set range will be described.

  FIG. 1 shows a configuration of a scanning confocal microscope system according to the present embodiment. In FIG. 1, the scanning confocal microscope system generally includes a scanning confocal microscope, a computer (hereinafter referred to as a PC) 12, and a monitor 15.

In this scanning confocal microscope, light emitted from the light source 1 passes through the beam splitter 2 and then enters the two-dimensional scanning mechanism 3.
The two-dimensional scanning mechanism 3 includes a first optical scanner 3a and a second optical scanner 3b. In the two-dimensional scanning mechanism 3, the light beam from the light source 1 is two-dimensionally scanned by the first optical scanner 3 a and the second optical scanner 3 b, and the light beam is guided to the objective lens 7.

  The light beam incident on the objective lens 7 becomes focused light and scans the surface of the sample 8. The light reflected from the surface of the sample 8 is again introduced into the beam splitter 2 from the objective lens 7 via the two-dimensional scanning mechanism 3. Then, the light reflected by the beam splitter 2 is condensed on the pinhole 10 by the imaging lens 9.

  In the pinhole 10, only the light from the condensing point of the sample 8 passes, and the reflected light from other than the condensing point of the sample 8 is cut. The light passing through the pinhole 10 is detected by the photodetector 11.

  The Z revolver 6 has a plurality of objective lenses 7, and the objective lens 7 having a desired magnification can be inserted into the optical path for two-dimensional scanning. Further, since the Z revolver 6 is movable in the Z-axis direction, the condensing position of the objective lens 7 and the relative position of the sample 8 can be changed.

The sample 8 is placed on the sample stage 13 and can be moved in the XY (perpendicular direction to the optical axis) direction by the stage 14.
The PC 12 is connected to components of the scanning confocal microscope such as the two-dimensional scanning mechanism 3, the Z revolver 6, and the photodetector 11. These components are controlled by a microscope control program stored in the PC 12. Therefore, the user can operate each unit constituting the scanning confocal microscope through a predetermined screen displayed on the monitor 15.

  Here, the condensing position by the objective lens 7 is at a position conjugate with the pinhole 10. For example, when the sample 8 is at a condensing position by the objective lens 7, the reflected light from the sample 8 is condensed on the pinhole 10 and passes through the pinhole. When the sample 8 is located at a position deviated from the condensing position by the objective lens 7, the reflected light from the sample 8 does not pass through the pinhole.

FIG. 2 shows the relationship (I-Z curve) between the relative position (Z) in the Z direction between the objective lens 7 and the sample 8 and the detection signal level (I) of the photodetector 11. When the sample 8 is at the condensing position Z _c of the objective lens 7, the detection signal level output from the photodetector 11 becomes the maximum, and as the relative position between the objective lens 7 and the sample 8 increases from this position, the photodetector The detection signal level of 11 drops rapidly.

  With this characteristic, if the condensing point is two-dimensionally scanned by the two-dimensional scanning mechanism 3 and the output of the photodetector 11 is imaged in synchronization with the two-dimensional scanning mechanism 3, only a certain height of the sample 8 is obtained. An image (confocal image) obtained by imaging and optically slicing the sample 8 is obtained. The image is displayed on the monitor 15 together with the operation screen.

Next, a sample information measuring method to which this embodiment is applied will be described.
FIG. 3 shows an example of the sample 8 used for observation in order to explain the present embodiment. In the figure, a sample having a step between an upper surface A and a lower surface B is shown. Hereinafter, the sample 8 will be described as an observation target.

  FIG. 4 shows a two-dimensional image captured by the scanning confocal microscope according to the present embodiment. This figure is a two-dimensional image 20 displayed on the monitor 15 by imaging the sample 8 of FIG. 3 from the upper surface side (Z-axis direction) with a scanning confocal microscope. Note that the two-dimensional image may be an image captured by an imaging unit (CCD or the like not shown) of the scanning confocal microscope.

  When the two-dimensional image 20 is displayed on the monitor 15, the operator can arbitrarily set the position and size of the region setting frame 23 using an input device (such as a mouse (not shown)) of the PC 12. Here, the region setting frame 23 is set in accordance with the contour of the upper surface A in FIG.

  In the present embodiment, the area set in the area setting frame 23 is the first area 21, and the area outside the area setting frame 23 is the second area 22. The area can be set by setting a plurality of rectangles, a circle including an ellipse, and a figure surrounded by an arbitrary curve.

  FIG. 5 shows a region height range setting table in the present embodiment. The area height range setting table 30 is an area height range setting table for setting and storing a capture height range for each area. In the area height range setting table 30, the lower limit and the upper limit of the Z position of each area set in FIG. 4 can be set. The area height range setting table 30 is stored in a storage device (not shown) of the computer 12.

  FIG. 6 shows an example of the sample surface height and the effective capture range for each region in the present embodiment. This figure shows a case where the sample 8 of FIG. 3 is observed from the side surface direction. The vertical axis indicates the relative position in the Z direction between the objective lens 7 and the sample 8.

  In FIG. 6, the range from the capture start position 40 to the capture end position 41 is the scanning target range. Among these, the range in which the image is actually captured is a portion indicated by a data valid range 42 in the first area 21 and a data valid range 43 in the second area 22.

  FIG. 7 shows a processing flow for setting the Z position in the region height range setting table 30 in the present embodiment. This flow is executed by the PC 12. Here, it is assumed that the area shown in FIG. 4 has been set in advance.

The operator first observes the sample 8 with a confocal image on the monitor 15 (step 1. Hereinafter, the step is referred to as “S”).
Next, the operator lowers the Z revolver 6 until the lower surface B becomes invisible, and determines the capture start position (S2). Here, the operator controls the Z revolver 6 with the PC 12 and lowers the Z revolver 6 to a position where the lower surface B cannot be seen while referring to the monitor 15. Thereafter, when the operator presses a predetermined button on the operation screen of the PC 12, for example, the stop position of the Z revolver 6 is determined as the capture start position 40. The Z position information at that time is read into the PC 12 and stored in the area height range setting table 30.

  Next, the operator raises the Z revolver 6 until the upper surface A becomes invisible, and determines the capture end position (S3). Here, the operator controls the Z revolver 6 by the PC 12 and raises the Z revolver 6 to a position where the upper surface A cannot be seen while referring to the monitor 15. Thereafter, when the operator presses a predetermined button on the operation screen of the PC, for example, the stop position of the Z revolver 6 is determined as the capture end position 41. The Z position information at that time is read into the PC 12 and stored in the area height range setting table 30.

  Next, the operator controls the Z revolver 6 with the PC 12, lowers the Z revolver 6 again, and the upper and lower Z positions at which the upper surface A designated in the first region 21 cannot be seen (in FIG. 6, The upper and lower limits of the data valid range 42 of the first area 21 are registered (S4). In this state, for example, an image of a table as shown in FIG. 5 is displayed on the monitor 15 in an observing state, and the place indicating the lower limit and the upper limit Z position of each area in the screen is a button. The Z position information of the monitor 15 may be displayed by being registered in the area height range setting table 30 in the PC 12 by pressing each button.

  Furthermore, the operator controls the Z revolver 6 with the PC 12 to lower the Z revolver 6, and the upper and lower Z positions at which the lower surface B cannot be seen (in FIG. 6, the data valid range of the second area 22 43 (upper limit and lower limit) are registered in the same manner as described above (S5). The process here is the same as S4.

  In the example of FIG. 6, the lower limit of the data valid range 43 of the capture start position 40 and the first area 21, and the upper limit of the data valid range 43 of the capture end position 41 and the second area 22 are the same position. It is not limited to this. For example, the lower limit of the data valid range 43 of the capture start position 40 and the first area 21 and the upper limit of the data valid range 43 of the capture end position 41 and the second area 22 may be different.

  In the example of FIG. 6, there are two areas to be set, but the present invention is not limited to this. For example, a region larger than that may be set. In this case, it is necessary to repeat the registration of the upper limit and the lower limit of the area. Note that the procedure in FIG. 7 is an example, and the procedure from S2 to S5 may be switched.

Next, as an example from the scanning range, the operation on the pixel (x ₁ , y ₁ ) in the first region 21 shown in FIG. 4 will be described with reference to FIG.
FIG. 8 shows a flow for constructing an observation image in the present embodiment. This flow is a process in which a program according to the present embodiment stored in the storage device of the PC 12 is read out and executed by the control device of the PC 12. In the following flow, the counter variable relating to the Z position is i (initial value: i = 0), the counter variable for specifying the region in the image is n (initial value: n = 1), and the coordinates (x, y, z). ) Is represented by I (x, y, z), and the maximum luminance value is represented by I _max (initial value: I _max = 0).

First, move the Z revolver 6 in Z _i position (S11). The process time of the first time (i = 0), is instructed to capture start from PC12, Z revolver 6 moves to the capture start position Z _0. Then, a two-dimensional image at the Z position is acquired (S12).

Next, in the acquired two-dimensional image, it is determined which region the pixel (x, y) currently focused on is included (S13, S14). For example, in the case of FIG. 4, the pixel (x _1, y ₁₎ is determined to be included in the second region 22.

  Next, the capture height range R corresponding to the region determined in S13 is read from the region height range setting table 30. In the above case, “second region lower limit: 1000, upper limit: 2400” is acquired as the capture height range R from the region height range setting table 30 of FIG.

Next, it is determined whether or not the position Z _i of the Z revolver 6 is within the capture height range R of the region determined in S13 (S16). In the above case, it is determined whether the position Z _i of the Z revolver 6 is within the capture height range R (lower limit: 1000 to upper limit: 2400) corresponding to the second region 22 (S16). If the position Z _i of the Z revolver 6 is outside the capture height range R (proceed to “No” in S16), the process proceeds to S18.

If the position Z _i of the Z revolver 6 is within the capture height range R (proceed to “Yes” in S16), the luminance value I (x, y, z) of the pixel (x, y) is the maximum luminance value. It is compared with I _max (S17). In the above case, the luminance value I (x ₁ , y ₁ , z ₀ ) of the pixel (x ₁ , y ₁ ) is compared with the maximum value I _max (S17).

Next, the luminance value I of a pixel (x, y) is (advances in S17 to "Yes") is greater than the maximum value I _max, stores the brightness value to the maximum value I _max. At the same time, the height information Z _i at that time is stored as Z _p (S18).

In the determination of S17, the luminance data of the pixel (x, y) is (advances in S17 to "No") equal to or smaller than the maximum value I _max, the processing proceeds to S19.
Next, the counter variable i is incremented, and the Z position is calculated so that the Z revolver moves by a predetermined movement amount (S19). The process returns to S11 and repeats the same process until the capture end position 42 is exceeded (S20).

  For convenience of explanation, S13 to S18 in FIG. 8 show the action for a specific pixel as an example, but in practice, the same processing is applied to all the pixels in the two-dimensional scanning range. An observation image can be constructed based on the pixel data thus obtained.

  When a two-dimensional image is captured in this way, the maximum luminance value of each pixel in each region in the capture height range R can be acquired. That is, the maximum luminance value and the coordinates (x, y, z) of the pixel having the maximum luminance value are acquired as representative pixel data. In the above case, as the luminance data for the pixel (x1, y1), only the maximum luminance data among the luminance data acquired at the Z position within the data effective range of the second region 22 is acquired as effective information.

  In the present embodiment, the maximum luminance data is acquired from the luminance data acquired at the Z position within the data valid range of each region, but the present invention is not limited to this. For example, by applying the method shown in Patent Document 2, the Z revolver 6 is discretely changed in the Z direction, the light intensity from the sample at each relative position is detected, and a plurality of values including the maximum light intensity detection value are included. Based on the detected light intensity value, the relative position value that gives the maximum value on the change curve indicated by the light intensity may be estimated, and the luminance value corresponding to the estimated relative position value may be calculated as representative pixel data. .

  Further, for example, by applying the method shown in Patent Document 2, the Z revolver 6 is discretely changed in the Z direction to detect the light intensity from the sample at each relative position, and among these light intensity detection values. The maximum light intensity detection value and the minimum light intensity detection value are extracted from the above, and the change curve indicated by the light intensity by linear approximation with the two light intensity detection values before and after sandwiching the average value of the two light intensity detection values The two Z positions giving the average value are obtained, the midpoint of the two Z positions is estimated as the relative position value giving the maximum value on the change curve, and the luminance value corresponding to the estimated relative position is calculated. It may be calculated as representative pixel data.

  According to the present embodiment, the representative value of each pixel can be obtained in each observation range arbitrarily set by the user in the Z direction. Thereby, since information other than the vicinity of the surface height of interest is ignored and the height information is acquired, it is possible to acquire a height image that is hardly affected by noise.

<Second Embodiment>
In this embodiment, when there is a part with different reflectivity or a transmissive surface, an arbitrary range is set for the Z direction of the region corresponding to each part or surface, and the revolver is displaced within the range in the Z direction. A microscope system that acquires the highest pixel value among the luminance values of each pixel of the image captured in this manner will be described. In addition, about this embodiment, only a different part from 1st Embodiment is demonstrated.

  FIG. 9 shows a two-dimensional image captured by the scanning confocal microscope according to the present embodiment. This figure is a two-dimensional image 50 displayed on the monitor 15. The operator sets the first region 51 and the second region 52 by dividing the two-dimensional image 50 into left and right parts as in FIG. 4 while referring to the monitor 15. As will be described later, it is assumed that the reflectance of the second region 52 (lower film surface) is lower than the reflectance of the first region 51 (upper film surface).

  FIG. 10 shows the IZ curve and the sample surface height of the transparent film, which is a sample in this embodiment, and the effective loading range for each region. As shown in the IZ curve, the reflectance of the lower film surface is lower than the reflectance of the upper film surface.

  As described above, the area is set in the same manner as in the first embodiment. As described with reference to FIG. 9, the two-dimensional image 50 is divided into right and left parts, and a first region 51 (film upper surface side) and a second region 52 (film lower surface side) are set.

Further, as in the first embodiment, the data valid range 62 of the first area 51 and the data valid range 63 of the second area 52 are determined.
FIG. 11 shows an area height range setting table in the present embodiment. The area height range setting table 70 is obtained by adding a data item “gain” to the area height range setting table 30 of FIG. In the data item “gain”, the gain of the photodetector 11 adjusted corresponding to each region can be stored. Here, although gain is taken up, setting items related to imaging other than gain may be used. The area height range setting table 70 is stored in the storage device of the computer 12.

FIG. 12 shows a flow for constructing an observation image in the present embodiment. This flow is a process in which a program according to the present embodiment stored in the storage device of the PC 12 is read out and executed by the control device of the PC 12. In the following flow, the counter variable relating to the Z position is i (initial value: i = 0), the counter variable for specifying the region in the image is n (initial value: n = 1), and the coordinates (x, y, z). ) Is represented by I (x, y, z), and the maximum luminance value is represented by I _max (initial value: I _max = 0).

First, the Z revolver 6 is moved to the Z _i position (S21). The process time of the first time (i = 0), is instructed to capture start from PC12, Z revolver 6 moves to the capture start position Z _0. Then, a two-dimensional image at the Z position is acquired (S22).

Next, it is determined in which region the height capture range R is included in the Z position Z _i (S22, S23). Here, the upper and lower limits of each area in the area height range setting table 70 are compared with the current Z position Z _i, and the Z _i position falls within the upper and lower limits of the height capture range R corresponding to which area. It is judged whether it is in. Thereby, it is specified which region the current Z position Z _i belongs to.

  Next, a gain corresponding to the region determined in S22 is acquired from the region height range setting table 70, and the gain is set in the photodetector 11 (S24). A two-dimensional image is acquired with the set gain (S25).

Thereafter, the same processing as S13 to S18 of FIG. 8 described in the first embodiment is executed (S26).
Next, the counter variable i is incremented, and the Z position is calculated so that the Z revolver moves by a predetermined movement amount (S27).

  The process returns to S11 and repeats the same process until the capture end position Z is exceeded (S28). In this flow, for the sake of convenience of explanation, the action on a specific pixel is shown as an example. However, in practice, the same processing is performed on all the pixels in the two-dimensional scanning range. An observation image can be constructed based on the pixel data thus obtained.

  As shown in FIG. 10, the image acquired in this way is a data effective range of the first region 51 including the upper surface of the film having a high reflectance in the data effective range of the second region 52 including the lower surface of the film having a low reflectance. Since it is acquired with a higher gain than the above, it is possible to obtain an effect that there is little noise with a signal having a sufficient light amount.

  In the first area 51 shown in FIG. 9, since the maximum luminance is extracted from the luminance data within the data valid range of the first area 51 shown in FIG. 10, only the upper surface of the film is imaged. In the second area 52 shown in FIG. 9, since the maximum luminance is extracted from the luminance data within the data valid range of the second area 52 shown in FIG. 10, only the lower surface of the film is imaged.

  As a result, an image capable of simultaneously observing and displaying the upper and lower surfaces of the film in one image can be obtained by a single capture operation. In addition, the measurement of the film thickness (which can be obtained from the interval between the peak values of the I-Z curve) that has been conventionally performed on the IZ profile is measured on the image acquired as described above. Is also possible. That is, the maximum luminance value of each pixel is acquired from the flow of FIG. 12, and the Z position information at that time is also acquired. That is, since each pixel of the image referred to after the flow of FIG. 12 has a luminance value and three-dimensional coordinate information, the relative distance in the Z direction between any two points in the image can be easily calculated.

(Modification)
Below, the modification of 2nd Embodiment is demonstrated. In this modification, a case where observation is performed using an infrared laser microscope instead of the scanning confocal microscope will be described.

  FIG. 13 shows a two-dimensional image captured by an infrared laser microscope in a modification of the present embodiment. For example, when a silicon substrate or the like is observed as a sample instead of a transparent film with an infrared laser microscope, a two-dimensional image 80 is obtained by executing the processing of FIG. The two-dimensional image 80 can obtain a visually effective image as seen through a region 82 of interest from the surface image 81 of the sample. In this example, a wiring pattern image on the back surface of the silicon substrate appears in the region 82 through the transmission.

  Even if there is a step between the surface and the surface obtained by internal transmission, the surface region and the surface region obtained by internal transmission are obtained by one image acquisition as in the first embodiment. be able to.

  In addition, when a certain sample is repeatedly observed, it is easy to obtain a good image for non-defective product determination by executing different image processing such as noise removal and feature extraction for each region after imaging.

Further, by setting auto focus at the center of each area and setting a certain range of height from the in-focus height to the effective range, the setting burden on the operator can be reduced.
According to the present invention, when there is a step on the measurement target surface of the sample, when there are parts having different reflectivities, and when there is a transmission surface, measurement can be performed without being affected by these. .

  The present invention is not limited to the embodiments described above, and can take various configurations or forms without departing from the gist of the present invention.

1 shows a configuration of a scanning confocal microscope system according to a first embodiment. The relationship (I-Z curve) between the relative position (Z) between the objective lens 7 and the sample 8 and the detection signal level (I) of the photodetector 11 is shown. An example of the sample 8 used for observation in order to explain the first embodiment is shown. The 2D image imaged with the scanning confocal microscope in 1st Embodiment is shown. The area | region height range setting table in 1st Embodiment is shown. The sample surface height in 1st Embodiment and the example of the taking-in effective range for every area | region are shown. 6 shows a processing flow for setting the Z position in the region height range setting table 30 in the first embodiment. 5 shows a flow for constructing an observation image in the first embodiment. The two-dimensional image imaged with the scanning confocal microscope in 2nd Embodiment is shown. The IZ curve of the transparent film which is a sample in 2nd Embodiment, the sample surface height, and the capture effective range for every area | region are shown. The area | region height range setting table in 2nd Embodiment is shown. 10 shows a flow for constructing an observation image in the second embodiment. The two-dimensional image imaged with the infrared laser microscope in the modification of 2nd Embodiment is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Beam splitter 3 Two-dimensional scanning mechanism 3a 1st optical scanner 3b 2nd optical scanner 6 Revolver 7 Objective lens 8 Sample 9 Imaging lens 10 Pinhole 11 Photo detector 12 PC
13 Sample stage 14 Stage 15 Monitor

Claims (8)

A light source that emits light;
Two-dimensional scanning means for relatively scanning the irradiation light irradiated from the light source with respect to the sample in a two-dimensional direction;
An objective optical system for condensing the scanned illumination light;
Photodetection means for detecting reflected light reflected by illuminating the sample with illumination light condensed by the objective optical system and outputting a detection signal corresponding to the detection intensity;
Two-dimensional image acquisition means for acquiring a two-dimensional image based on the detection signal output from the light detection means;
Relative position displacement means for relatively displacing the position of the sample with respect to the objective optical system;
A divided region related information storage unit storing information about a divided region observation range that is an observation range in the optical axis direction corresponding to a divided region obtained by dividing the measurement target range of the sample into a plurality of regions;
Representative pixel data for obtaining representative pixel data from each pixel data of the two-dimensional image acquired in the divided region observation range when the sample is displaced by the relative position displacement means in each divided region observation range. Acquisition means;
Observation image construction means for constructing an observation image based on the representative pixel data;
A confocal scanning microscope system comprising: The representative pixel data obtaining unit obtains pixel data having the maximum luminance among the pixel data of the two-dimensional image obtained within the divided region observation range as the representative pixel data. Item 2. The confocal scanning microscope system according to Item 1. When the sample is discretely displaced by the relative position displacing unit in each divided region observation range, the representative pixel data acquisition unit is configured to display each of the plurality of two-dimensional images acquired in the divided region observation range. The pixel data includes calculating a luminance value change curve based on pixel data including pixel data having a maximum luminance value, and acquiring the maximum value of the change curve as the representative pixel data. The confocal scanning microscope system described in 1. The confocal scanning microscope system further comprises:
Light detection control means for controlling the detection sensitivity of the light detection means according to the respective divided areas;
The confocal scanning microscope system according to claim 1, further comprising: The division area related information storage means further stores the detection level of the light detection means for each of the division areas,
The confocal point according to claim 4, wherein the light detection control unit acquires a detection level for each of the divided regions from the divided region related information storage unit, and controls detection sensitivity of the light detection unit. Scanning microscope system. 2. The confocal scanning microscope system according to claim 1, wherein the light source, the objective optical system, and the light detection means are an infrared light source, an infrared optical system, and an infrared light detection device, respectively. The confocal scanning microscope system according to claim 1, wherein the representative pixel data includes at least a luminance value and position information in the optical axis direction. An observation method of a confocal scanning microscope system in which an observation image is displayed on a display device,
Dividing the measurement target range of the sample displayed on the display device into a plurality of regions,
Set the measurement range for each of the divided areas in the optical axis direction,
The relative position between the sample and the objective optical system of the confocal scanning microscope is changed in the optical axis direction, and the illumination light focused by the sample objective optical system is scanned in a two-dimensional direction to irradiate the sample. Detecting the reflected light reflected and obtaining a detection signal according to the detected intensity,
Obtaining representative pixel data having representative luminance information among luminance information of each pixel based on the detection signal acquired within the set measurement range;
An observation method characterized in that an observation image is constructed based on the representative pixel data.