JP2022040403A - Scan probe microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scan probe microscope that can display at least one of measurement data and a distribution image of the differential data, can obtain an edge emphasis image, and can increase the convenience for a user.

SOLUTION: The present invention relates to a scan probe microscope 200 including: a cantilever 1; and a displacement detector 5 for detecting a signal which shows a displacement of the cantilever, and the scan probe microscope acquires measurement data when a probe 99 is relatively scanned along the surface of a sample 300. The scan probe microscope 200 further includes: distribution image calculation means 40a for calculating a first distribution image 201 as a one-dimensional or two-dimensional image of the measurement data and a second distribution image 202 as a one-dimensional or two-dimensional image of differential data next to the measurement data; and display control means 40b for instructing the distribution image calculation means to calculate at least one of the first distribution image and the second distribution image and causing predetermined display means to display the calculated distribution image.

SELECTED DRAWING: Figure 4

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a scanning probe microscope that detects a physical interaction between a sample and a probe, controls the distance between the sample and the probe, and acquires physical measurement data that interacts with the sample.

A scanning probe microscope (SPM) measures the surface shape and physical properties of a sample by bringing a probe close to or in contact with the surface of the sample. There are many types of measurement modes of the scanning probe microscope, such as STM (scanning tunneling microscope) and AFM (scanning atomic force microscope). The most commonly used AFMs are (1) a contact mode that detects the atomic force between the probe and the sample as the deflection of the cantilever and keeps it constant to measure the surface shape of the sample, as well as (2) the cantilever. Is forcibly vibrated near the resonance frequency by a piezo element or the like, and when the probe is in contact with or close to the sample, the shape of the sample is changed by the intermittent force acting between the two. (Hereinafter, appropriately referred to as "dynamic force mode (DFM measurement mode)") and the like are known.
These scanning probe microscopes detect a signal indicating the displacement of the cantilever, and based on this signal, the probe of the sample is used while keeping the physical quantity (force and vibration amplitude) between the cantilever and the surface of the sample constant. The sample surface shape and the physical measurement data of the interaction between the cantilever and the sample are acquired by scanning relatively along the surface.

By the way, for example, the uneven image (shape image) of the sample surface obtained by using SPM is generally colored in high and low, and the low place is dark and the high place is bright. However, in the conventional shape image, when the sample surface contains large unevenness and small unevenness, if the color is arranged according to the height of the large unevenness, the contrast of the small unevenness becomes small and difficult to see, while the color is arranged according to the height of the small unevenness. Then, the contrast of the large unevenness exceeded the range, and it was difficult to express both in the same image.
On the other hand, conventionally, in the field of image processing, a technique called edge enhancement (image enhancement) has been used to generate a difference image of adjacent image data to make it easier to see. However, in the field of scanning probe microscopes, the difference data has been limited to the use for improving the accuracy of the image by removing the distortion component of the image, for example (see Patent Document 1). The reason for this is that edge enhancement in the field of scanning probe microscopes obtains an error signal image using an error signal which is a displacement signal of the cantilever in the scanning direction in the AFM and a displacement signal of the vibration amplitude of the cantilever in the scanning direction in the DFM. It is thought that it is done by.

Japanese Unexamined Patent Publication No. 11-94851

Therefore, when it is desired to differentiate the measurement data of the conventional scanning probe microscope and emphasize the edge, it is necessary to perform the difference processing of the captured measurement data with another software or the like and display the screen separately from the measurement data, which makes the work complicated. Inferior in convenience.
Further, depending on the application, there are cases where it is desired to acquire and display only the measurement data, there are cases where it is desired to acquire and display the difference data, or there are cases where it is desired to display both the measurement data and the difference data on the screen. For example, if the difference data is calculated uniformly in response to such various requests, there is a problem that the processing of the computer is wasted and the processing speed is lowered when the difference data is unnecessary. Further, it cannot be applied when it is desired to selectively acquire the difference data only in the case of a specific sample or surface shape.
A scanning probe microscope that displays both measurement data and difference data on the screen has not been developed so far.

Further, the error signal image in the field of the scanning probe microscope is based on the error signal obtained by making the light receiving amount of the quadrant light receiving cell for detecting the displacement of the cantilever uneven in the so-called optical lever system. In other words, it is a deviation from the displacement control standard, and it is ideal to control so that there is no deviation. Therefore, since the difference between the error signal image and the shape image becomes smaller as the measurement accuracy is improved, there is a problem that the error signal image cannot be used as an edge enhancement means as the measurement accuracy is improved.

The present invention has been made to solve the above problems, and it is possible to selectively or both display the measurement data and the distribution image of the difference data, and an edge-enhanced image can be obtained regardless of the measurement accuracy. It is an object of the present invention to provide a scanning probe microscope with improved user convenience.

In order to achieve the above object, the scanning probe microscope of the present invention includes a cantilever provided with a probe in contact with or close to the surface of the sample, and a displacement detector for detecting a signal indicating the displacement of the cantilever. , Measurements obtained when the probe is relatively scanned along the surface of the sample while maintaining a constant predetermined physical quantity between the cantilever and the surface of the sample based on the signal. In a scanning probe microscope for acquiring data, the first one-dimensional or two-dimensional distribution image of the measurement data and the measurement data are arranged in the order of the scanning direction, and separated from each scan in a direction intersecting the scanning direction. With respect to the distribution image calculation means for calculating the one-dimensional or two-dimensional second distribution image of the difference data of the adjacent data when they are arranged side by side and arranged on the two-dimensional surface, and the first distribution image calculation means. The feature is that a display control means for instructing the calculation of one or both of the distribution image and the second distribution image and displaying the calculated distribution image on a predetermined display means is further provided. do.

According to this scanning probe microscope, when the first distribution image consisting of measurement data is difficult to see, an edge-enhanced image can be obtained by calculating the second distribution image consisting of the difference data, and the physical quantity of the sample surface can be obtained. It becomes easier to see the distribution. In particular, by using the difference data, a second distribution image (edge-enhanced image) can be obtained regardless of the measurement accuracy, unlike the conventional scanning probe microscope using the error signal image.
Further, if the first distribution image and the second distribution image are displayed on one display means, the first image (for example, a shape image) which is the original image is compared with the case where one of the distribution images is displayed. Since the distribution image and the second distribution image composed of the difference data can be compared on one screen, more useful information can be obtained.

In the scanning probe microscope of the present invention, when the display control means displays both the first distribution image and the second distribution image, the measurement data and the difference data at the same position may be displayed at the same time. good.
According to this scanning probe microscope, since the first distribution image and the second distribution image at the same position are displayed at the same time, the difference between the two distribution images can be compared at the same position, and more useful information can be obtained.

The scanning probe microscope of the present invention further includes a calculation direction designating means for designating a calculation direction of data when calculating the first distribution image and the second distribution image, and the distribution image calculation means is the calculation. Of the first distribution image and the second distribution image, the distribution image displayed on the display means may be calculated along the calculation direction designated by the direction designating means.
Depending on the calculation direction of the data, the contrast of the first distribution image and the second distribution image may be lowered to make it difficult to see, and useful information may not be obtained. Therefore, according to this scanning probe microscope, by changing the calculation direction, the contrast of the first distribution image and the second distribution image is increased to make it easier to see, and more useful information can be obtained.

The scanning probe microscope of the present invention further includes a subtraction order designating means for designating a subtraction order of differences between adjacent data when calculating the second distribution image, and the distribution image calculation means is the subtraction. The second distribution image may be calculated in the deduction order designated by the order designating means.
Depending on the order in which the data is subtracted, the contrast of the second distributed image may decrease, making it difficult to see, and useful information may not be obtained. Therefore, according to this scanning probe microscope, the light and darkness of the second distribution image is reversed by changing the subtraction order, the contrast and the like are increased to make it easier to see, and more useful information can be obtained.

In the scanning probe microscope of the present invention, the display control means sequentially displays the second distribution image for each difference data along the scanning direction or the calculation direction, and the distribution image calculation means is the second distribution image. When the calculation direction and / or the deduction order is specified by the calculation direction designating means and / or the deduction order designating means, the specified calculation direction and / or the deduction order is displayed. The second distribution image may be calculated based on the above.
According to this scanning probe microscope, by sequentially displaying the second distribution image for each difference data, the calculation direction and / / when it is felt that the contrast of the second distribution image is lowered and becomes difficult to see. Alternatively, the subtraction order can be changed to make the subsequent second distribution image easier to see and to obtain useful information.

In the scanning probe microscope of the present invention, the distribution image calculating means recalculates the second distribution image based on the measurement data before the designation based on the designated calculation direction and / or the subtraction order. The display control means may display both the recalculated second distribution image and the designated second distribution image.
According to this scanning probe microscope, by sequentially displaying the second distribution image for each difference data, the contrast and the like of the second distribution image are lowered and it is difficult to see the past (calculated) first. Since the distribution image of 2 is recalculated by changing the calculation direction and / or the subtraction order, the second distribution image in the past can be easily seen and useful information can be obtained.

In the scanning probe microscope of the present invention, the display control means may display the measurement data and the difference data for each line in the scanning direction or the calculation direction.
According to this scanning probe microscope, the measurement data and / or the difference data is displayed for each line, so that the measurement data and / or the difference data can be immediately seen in real time. Further, when the measurement data and / or the difference data is difficult to see, it is possible to immediately respond (change the calculation direction and / or the deduction order).

According to the present invention, the measurement data of the scanning probe microscope and the distribution image of the difference data can be selectively or both displayed, an edge-enhanced image can be obtained, and the convenience of the user can be improved.

It is a block diagram of the scanning probe microscope which concerns on embodiment of this invention. It is a block diagram of a computer of a scanning probe microscope. It is a figure which shows the processing flow in a computer of a scanning probe microscope. It is a schematic diagram which shows the state which both the 1st distribution image and the 2nd distribution image are displayed on one monitor. It is a figure which shows the calculation direction of the 2nd distribution image when a sample has a convex part of a cross. It is a schematic diagram which shows the 2nd distribution image in the scanning direction of the sample of FIG. It is a schematic diagram which shows the 2nd distribution image when the calculation direction of the sample of FIG. 5 is orthogonal to the scanning direction. It is a figure which shows an example of the calculation direction of data. It is a schematic diagram which shows the mode which displays both the recalculated second distribution image and the designated second distribution image when the calculation direction is specified. It is a figure which shows the subtraction order of the difference of data at the time of calculating the 2nd distribution image. It is a schematic diagram which shows the mode that when the calculation direction and the deduction order are both specified, the recalculated second distribution image and the designated second distribution image are displayed together. It is a figure which shows the 1st distribution image and the 2nd distribution image of an actual sample. It is another figure which shows the 1st distribution image and the 2nd distribution image of an actual sample.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a scanning probe microscope 200 according to an embodiment of the present invention. Note that FIG. 1A is an overall view of the scanning probe microscope 200, and FIG. 1B is a partially enlarged view of the vicinity of the cantilever 1.
In FIG. 1A, the scanning probe microscope 200 includes a cantilever 1 having a probe 99 at its tip, a sample table 10 on which a sample 300 is placed, a cantilever vibration unit 3 that vibrates the cantilever 1, and a cantilever. A vibration power supply (vibration signal generator) 21 for driving the vibration unit 3, a displacement detector 5 for detecting a signal indicating the displacement of the cantilever 1, an AC-DC conversion mechanism 6, and a control means (probe). It has a microscope controller 24, a computer 40) and the like.
The probe microscope controller 24 has a frequency / vibration characteristic detection mechanism 7.
The computer 40 has a control board for controlling the operation of the scanning probe microscope 200, a storage means such as a CPU (central control processing unit), a ROM, a RAM, and a hard disk, an interface, an operation unit, and the like. Further, a monitor (display means) 41 and a keyboard 42 are connected to the computer 40.
The scanning probe microscope 200 is a sample scanning method in which the cantilever 1 is fixed and the sample 300 side is scanned.

The probe microscope controller 24 includes a Z control circuit 20, a frequency / vibration characteristic detection mechanism 7, a vibration power supply 21, an X, Y, Z output amplifier 22, and a coarse motion control circuit 23, which will be described later. The probe microscope controller 24 is connected to the computer 40 to enable high-speed data communication. The computer 40 controls the operating conditions of the circuit in the probe microscope controller 24, captures and controls the measured data, and realizes measurement of surface physical properties such as surface shape.
The probe microscope controller 24 appropriately amplifies the measurement data and acquires the sample surface shape and the physical quantity of the interaction between the cantilever and the sample. The bias power supply circuit 29 applies a bias voltage directly to the sample table 10 to obtain a probe. It is also used in KFM or the like for measuring the surface potential between 99 and the sample 300.

The computer 40 corresponds to the "distribution image calculation means", "display control means", "calculation direction designation means", and "subtraction order designation means" in the claims.

The coarse motion mechanism 12 roughly moves the actuator 11 and the sample table 10 above the actuator 11 in three dimensions, and the operation is controlled by the coarse motion control circuit 23.
The actuator (scanner) 11 moves (finely moves) the sample table 10 (and the sample 300) in three dimensions, and scans the sample table 10 in the xy (plane of the sample 300) direction, respectively, in two (two-axis) directions. ) It is a cylinder provided with piezoelectric elements 11a and 11b and a piezoelectric element 11c that scans the sample table 10 in the z (height) direction. Piezoelectric elements are elements in which the crystal is distorted when an electric field is applied, and an electric field is generated when the crystal is forcibly distorted by an external force. As a piezoelectric element, PZT (lead zirconate titanate), which is a type of ceramic, is generally used. Although it can be used, the shape and operation method of the coarse motion mechanism 12 are not limited to this.
The piezoelectric elements 11a to 11c are connected to the X, Y, Z output amplifier 22, and a predetermined control signal (voltage) is output from the X, Y, Z output amplifier 22 to drive the piezoelectric elements 11a and 11b in the xy direction, respectively. , Drive the piezoelectric element 11c in the z direction. The electric signal output to the piezoelectric element 11c is detected in the probe microscope controller 24 and is taken in as the above-mentioned "measurement data".

The sample 300 is placed on the sample table 10, and the sample 300 is arranged to face the probe 99.
The cantilever 1 is in contact with the side surface of the cantilever tip portion 8 and constitutes a cantilever structure. The cantilever tip portion 8 is pressed against the slope block 2 by the cantilever tip portion retainer 9, and the slope block 2 is fixed to the exciter 3. Then, the vibrating machine 3 vibrates by the electric signal from the vibrating power source 21, and vibrates the cantilever 1 and the probe 99 at the tip thereof. The vibration method of the cantilever includes a piezoelectric element, an electric field or a magnetic field, light irradiation, and energization of an electric current.

Then, the laser light from the laser light source 30 is incident on the die clock mirror 31 and irradiates the back surface of the cantilever 1, and the laser beam reflected from the cantilever 1 is reflected by the mirror 32 and detected by the displacement detector 5. The displacement detector 5 is, for example, a 4-split photodetector, and the displacement amount in the vertical direction (z direction) of the cantilever 1 is detected by the displacement detector 5 as a change (incident position) in the optical path of the laser reflected from the cantilever 1. Will be done. That is, the vibration amplitude of the cantilever 1 corresponds to the amplitude of the electric signal of the displacement detector 5.
The amplitude of the electric signal of the displacement detector 5 passes through the preamplifier 50 and is appropriately amplified, and is converted into a DC level signal corresponding to the magnitude of the amplitude by the AC-DC conversion mechanism 6.

The DC level signal of the AC-DC conversion mechanism 6 is input to the Z control circuit 20. The Z control circuit 20 transmits a control signal to the Z signal section of the Z output amplifier 22 so as to match the target amplitude of the probe 99 in the DFM measurement mode, and the Z signal section drives the piezoelectric element 11c in the z direction. Outputs a control signal (voltage). That is, the displacement of the cantilever 1 caused by the atomic force acting between the sample 300 and the probe 99 is detected by the above-mentioned mechanism, and the actuator 11c is displaced so that the vibration amplitude of the probe 99 (cantilever 1) becomes the target amplitude. The contact force between the probe 99 and the sample 300 is controlled. Then, in this state, the actuators 11a and 11b are displaced in the xy direction by the X, Y, and Z output amplifiers 22 to scan the sample 300, and the surface shape and physical property values are mapped.

Further, the DC level signal of the AC-DC conversion mechanism 6 is input to the frequency / vibration characteristic detection mechanism 7 of the probe microscope controller 24. Further, the electric signal from the vibration power supply 21 is also input to the frequency / vibration characteristic detection mechanism 7. The frequency / vibration characteristic detection mechanism 7 processes a predetermined frequency / vibration characteristic signal calculated based on the input from the AC-DC conversion mechanism 6 and the excitation power supply 21, and performs sin, cos, amplitude signal, etc. by lock-in detection. Is acquired and transmitted to the computer 40.
Then, with respect to the displacement of the sample table 10 in the xy plane, (i) a three-dimensional shape image is obtained from the displacement of the height of the sample table 10, (ii) a phase image is obtained from the phase value in the resonance state, and (iii). Operates as a probe microscope by displaying an error signal image due to the difference between the vibration amplitude and the target value, and (iv) a multifunctional measurement image from the physical property values between the probe samples on the computer 40, and performing analysis and processing. Let me.

Next, a feature portion of the present invention will be described with reference to FIGS. 2 to 10. The present invention selectively or both calculates a one-dimensional or two-dimensional first distribution image of measurement data and a one-dimensional or two-dimensional second distribution image of difference data of adjacent data of measurement data. To display. Hereinafter, the case where the measurement data is shape data will be described as an example.

As shown in FIG. 2, the display control means 40b instructs the keyboard 42 to calculate the distribution image requested by the user. The distribution image calculation means 40a takes in the measurement data from the probe microscope controller 24 and calculates the distribution image instructed by the display control means 40b.
Further, the distribution image calculation means 40a calculates the first distribution image and the second distribution image in the calculation direction according to the instruction from the calculation direction designating means 40c. Similarly, the distribution image calculation means 40a calculates the second distribution image in the deduction order according to the instruction from the deduction order designating means 40d.
The user gives instructions to the calculation direction designating means 40c and the deduction order designating means 40d from the keyboard 42.
Then, the display control means 40b causes the monitor 41 to display the distribution image calculated by the distribution image calculation means 40a.

Next, the processing flow in the computer 40 will be described.
In FIG. 3, for example, the user wants to acquire (display) either the first distribution image or the second distribution image (in this example, both the first distribution image and the second distribution image) from the keyboard 42. When the request is input, the display control means 40b instructs the distribution image calculation means 40a to calculate the requested distribution image (step S100).
The distribution image calculation means 40a calculates the instructed distribution image for each line after the determination process in step S110 described later (step S102).
The display control means 40b causes the monitor 41 to display the calculated distribution image for each line (step S104).
Here, unless otherwise specified in step S110 described later, in steps S102 and 104, the calculation direction and the subtraction order described later are default values (for example, the calculation direction is the same as the scanning direction). Further, when the calculation direction is the same as the scanning direction, one line corresponds to one scanning line.

FIG. 4 is a schematic diagram showing a state in which both the first distribution image 201 and the second distribution image 202 are displayed on one monitor 41 by the processing of FIG. L1 to L3 of the first distribution image 201 each show a distribution image of one-dimensional measurement data for each line in this order. Similarly, D1 to D3 of the second distribution image 202 show distribution images of one-dimensional difference data for each line in this order. Then, by arranging each line over time, a two-dimensional distribution image of measurement data and difference data can be obtained.

The first distribution image 201, which is a shape image, includes a large mountain M1 and a small mountain M2, and when the colors are arranged two-dimensionally according to the height of the large unevenness, the contrast of the small mountain M2 becomes small. There are problems such as being difficult to see.
Therefore, by calculating and displaying the second distribution image 202 composed of the difference data of the adjacent measurement data, for example, even if the large mountain M1 and the small mountain M2 are included in the same image, the edge is emphasized. A clear image 202 that distinguishes the mountains M1 and M2 can be obtained.

In particular, if the first distribution image 201 and the second distribution image 202 are displayed on one monitor 41, the first distribution image (for example, a shape image) is the original image as compared with the case where one of the distribution images is displayed. Since the distribution image 201 of 1 and the second distribution image 202 composed of the difference data can be compared on one screen, more useful information can be obtained.
In particular, if the measurement data and the difference data at the same position are displayed simultaneously in the first distribution image 201 and the second distribution image 202, the difference between the two distribution images can be compared at the same position, which is more useful information. Is obtained.

Here, the "same position" may be, for example, one corresponding to one pixel of the measurement data, but since it is usually displayed for each line such as a scanning line, a specific one line of the measurement data and one thereof. The data for one line based on the difference data based on the measurement data of the line may be set at the same position.
Further, "simultaneously" means that when one pixel of the measurement data is sequentially displayed, one pixel of the measurement data and one pixel of the difference data before and after the measurement data are associated with each other and displayed at the same time. However, since display is normally performed for each line such as a scanning line, one specific line of measurement data and one line of data based on the difference data may be displayed at the same time.
Further, as long as it is included in the above purpose, the unit of other data may be displayed at "same position" or "simultaneously" (for example, two lines are displayed at the same time as one unit).

By the way, as shown in FIG. 5, for example, when the sample 301 has a convex portion of a cross, if the scanning direction S1 is parallel to one of the crosses, the sample 301 passes through the center of the cross of the convex portion on a flat surface. No unevenness information can be obtained when scanning, and as shown in FIG. 6, the second distribution image 202x, which is the difference data, may be flat and do not contain useful information.
Therefore, assuming that the calculation direction S2 for calculating the first distribution image and the second distribution image is not the same direction as the scanning direction S1 but, for example, a vertical direction crossing a cross, the second distribution image is shown in FIG. Useful information can be included in the distribution image 202y.

The process of FIG. 7 can be performed as in steps S110 to 114 of FIG.
First, the distribution image calculation means 40a determines whether or not the data calculation direction and / or the deduction order is specified after step S100 and before S102 (step S110). The deduction order will be described later.
Here, the calculation direction can be specified by, for example, when the user inputs the calculation direction from the keyboard 42, the calculation direction designating means 40c sets the calculation direction in the distribution image calculation means 40a.
If "Yes" in step S110, the process proceeds to step S112, and if "No", the process proceeds to step S102.

In step S112, the distribution image calculation means 40a is a distribution image displayed on the display means among the first distribution image and the second distribution image along the designated calculation direction (in this example, the first distribution image). Both the distribution image and the second distribution image) are calculated for each line.
Subsequently, if "No" is obtained in step S114, the process proceeds to step S104, and the distribution image calculated in the designated calculation direction is displayed.

FIG. 8 shows an example of the data calculation direction. A1 to a9 in FIG. 8 show individual measurement data.
Assuming that the direction in which the measurement data a1, a2, and a3 are lined up is the scanning direction S1, there are many calculation directions different from the scanning direction S1. Is not limited as long as it is a direction connecting individual measurement data in a row, such as the calculation direction S31 which is a bisector of 90 degrees), the calculation direction S32 between S1 and S31, and the calculation direction S33 between S2 and S31. ..
Further, the 1 line is, for example, in the case of the calculation direction S31, all the data on the individual lines parallel to the calculation direction S31. In FIG. 8, the data a1, a5, a9 are 1 line, and the data a4, a8 are 1. It is a line. Further, when the calculation direction is diagonal to the scanning direction S1 (excluding the calculation direction S2 orthogonal to the scanning direction S1) as in the calculation direction S31, the number of data in one line is not constant. In that case, there may be two or three different data in one line. However, if one line has one data, it is excluded from the calculation direction.

By the way, there are cases where the user looks at the second distribution image 202 of FIG. 6 sequentially for each line and decides that it is better to change the calculation direction S2 from the middle, but rather the optimum calculation direction is known from the beginning. It is considered that the calculation direction is often corrected after seeing the second distribution image 202.
In this case, as shown in FIG. 9A, each of the three lines D1, D2, D3 is displayed from the measurement start, and when the user who sees this changes the calculation direction S2, the second distribution image 202xy In, the flat distribution image in each line D1, D2, D3 and the distribution image of each line D4 to D6 in the calculation direction S2 coexist, and it may be difficult to grasp the whole image in the calculation direction S2.

Therefore, as shown in FIG. 9B, the second distribution image is recalculated for each line in the calculation direction S2 for the measurement data before the calculation direction S2 is changed (before the designation), and the calculation direction after the designation is made. It is preferable to display it together with the second distribution image of S2 (each line D4 to D6).
In FIG. 9B, in the scanning direction S1 before designation, the second distribution image based on the measurement data is obtained in three lines (D1 to D3), but as shown in the calculation direction S31 in FIG. 8, the calculation direction. When is slanted with respect to the scanning direction S1, even if the measurement data from the measurement start is the same, the obtained second distribution image does not always have the same number of lines and decreases to two lines (D11, D12). It doesn't matter.

The process of FIG. 9B can be performed as in steps S114 to 120 of FIG.
First, the distribution image calculation means 40a determines whether or not to recalculate the second distribution image before the designation of the calculation direction after step S112 (step S114).
Here, whether or not to recalculate can be determined by, for example, when the user inputs a request for recalculation from the keyboard 42, and the distribution image calculation means 40a acquires the request. Further, it may be set to be recalculated by default.
If "Yes" in step S114, the process proceeds to step S116 to determine whether or not there is a flag described later. If "Yes", the process proceeds to step S104, and if "No", step S118. Move to.

In step S118, the distribution image calculation means 40a recalculates the second distribution image in the calculation direction designated by the measurement data before the designation, and sets a flag to the effect that the second distribution image has been recalculated.
Subsequently, in step S120, the display control means 40b displays the second distribution image recalculated in S118 and the second distribution image after designating the calculation direction on the monitor 41 together.
Following step S120 or step S104, in step S130, the distribution image calculation means 40a determines whether or not the measurement data has been completed, and if "Yes", the process is terminated, and if "No", the step. Return to S110 and repeat the process.

When the second distribution image is recalculated in the first step S114, the second distribution image recalculated in S120 after the flag is set in S118 and the second distribution image after the calculation direction is specified. Are displayed together. Next, in the second and subsequent steps S114, since the flag indicating that the recalculation has already been set is set, it is determined as "No", and the process proceeds to S104 without further recalculation.
That is, for example, in FIG. 9B, the second distribution images D11 and D12 recalculated in the first step S114 and the second distribution images D4 to D6 after designating the calculation direction are collectively displayed. In the second and subsequent steps S114, the second distribution image after the designation is added after D6 for each line.

Next, the deduction order will be described with reference to FIGS. 10 and 11.
As shown in FIG. 10A, when calculating the second distribution image, the order of subtracting the differences between the adjacent data is as follows: (1) Time-series from the later data a2 on one line. In addition to calculating the difference D (= a2-a1) by subtracting the previous data a1, there is a method of calculating the difference −D (= a1-a2) in the reverse order of (2) and (1). Then, the difference D and the difference −D are opposite in height and have the effect of reversing the brightness of the second distribution image. When the second distribution image due to the difference D is difficult to see, the difference is reversed. Displaying -D may make it easier to see. In this way, the deduction order can be selected according to the purpose.
Therefore, for example, in FIG. 7, when the second distribution image 202 of D1 to D3 is difficult to see, for example, when the user inputs the deduction order from the keyboard 42, the deduction order designating means 40d distributes the deduction order. It can be set to the image calculation means 40a.

The adjacent data for which the difference D is obtained is not limited to the data string along the horizontal axis of FIG. 8 as shown in FIG. 10 (a), but the data along the vertical axis of FIG. 8 as shown in FIG. 10 (b), for example. It may be a column or a data column diagonally along the horizontal axis and the vertical axis.
Hereinafter, the difference in FIG. 10B based on the data string along the vertical axis of FIG. 8 is represented by D'and −D'.

The process of calculating the second distribution image by the distribution image calculation means 40a in the deduction order designated by the deduction order designating means 40d is performed in the designated calculation direction in steps S110 to S120 (FIG. 3). Is similar to.
Further, as shown in FIG. 11, both the calculation direction and the deduction order can be specified. In this case, in FIG. 11A corresponding to FIG. 9B, the difference corresponding to the difference D by the user who sees the second distribution image (each line D11, D12, D4 to D6) in the calculation direction S2. When the subtraction order d is changed to -d corresponding to the difference -D, the second distribution image (each line D11, D12, D4 to D6) before the subtraction order is changed is the second in the subtraction order-d. It is preferable to recalculate the distribution image of the above and display it together with the second distribution image (each line D7 or later) in the specified subtraction order. The second distribution image recalculated in the deduction order −d is schematically represented by lines D110, D120, D40 to D60.

12 and 13 show actual measurement examples of the first distribution image (shape image) and the second distribution image based on the difference. Note that FIG. 12 is an image of a sample in which a plurality of corrugated ridges are arranged in parallel, and FIG. 12 is an image of a sample in which a plurality of linear ridges are arranged in parallel.
12 (a) is the first distribution image (shape image) P1, and FIGS. 12 (b) and 12 (c) are differences + D and −D along the horizontal axis of FIG. 8 (see FIG. 10 (a), respectively). ) Is shown in the second distribution images P1 _{+ D} and P1- _D .
On the other hand, in FIGS. 12 (d) and 12 (e), the second distribution images P1 _{+ D' and} P1- Indicates _D' .
The same applies to FIG. 13, and the reference numerals P1 in FIG. 12 are replaced with P2, respectively.
It can be seen that the high and low (bright and dark) are reversed between the difference + D and -D, and the high and low (bright and dark) are similarly reversed between the difference + D'and-D'. Therefore, more information can be obtained by obtaining a second distribution image by performing a predetermined difference as needed.

Although only the second distribution image is displayed in FIGS. 7, 8 and the like, when both the first distribution image and the second distribution image are displayed in step S104, the corresponding first distribution image is displayed. Needless to say, the calculation is performed again in the calculation direction S2 after the designation, as in FIGS. 7 and 8.

The present invention is not limited to the above embodiment.
For example, in the above embodiment, the case where the measurement data is shape data has been described, but other physical quantities that can be measured by a scanning probe microscope may be used. Further, in the above embodiment, the DFM measurement mode has been described, but the present invention can be applied to, for example, the contact mode. For example, the present invention can be applied when measuring a friction image in a contact mode.
The present invention can also be applied to a lever scan method in which the cantilever side of a scanning probe microscope is scanned for measurement.

1 Cantilever 5 Displacement detector 40a Distribution image calculation means 40b Display control means 40c Calculation direction designation means 40d Subtraction order designation means 41 Display means (monitor)
99 Probe 200 Scanning probe microscope 201 First distribution image 202, 202x Second distribution image 202y Second distribution image after specifying the calculation direction 206 Second distribution image after specifying the subtraction order 300,301 Sample S1 Scanning direction S2, S31, S32, S33 Calculation direction L1 to L3 One line in the scanning direction D1 to D3, D4 to D7, D11, D12, D110, D120, D40 to D60 One line in the calculation direction

In order to achieve the above object, the scanning probe microscope of the first aspect of the present invention is a cantilever provided with a probe that comes into contact with or is in close proximity to the surface of a sample, and a displacement that detects a signal indicating the displacement of the cantilever. When the probe is relatively scanned along the surface of the sample while the detector is provided and the predetermined physical quantity between the cantilever and the surface of the sample is kept constant based on the signal. In a scanning probe microscope for acquiring the measurement data obtained in the above, the direction in which the one-dimensional or two-dimensional first distribution image of the measurement data and the measurement data are arranged is the scanning direction, and the scanning direction and the scanning direction are defined as the scanning direction. The calculation direction is the direction orthogonal to each other or the direction that is the bisector of the angle formed by the scanning direction and the direction orthogonal to the scanning direction, and the difference data of the data adjacent to the calculation direction is one-dimensional or two-dimensional. The distribution image calculation means for calculating the second distribution image and the distribution image calculation means are instructed to calculate one or both of the first distribution image and the second distribution image, and the said person concerned. It is further provided with a display control means for displaying the calculated distribution image on a predetermined display means.

The scanning probe microscope of the second aspect of the present invention includes a cantilever provided with a probe that comes into contact with or is close to the surface of the sample, and a displacement detector that detects a signal indicating the displacement of the cantilever. Based on this, the measurement data obtained when the probe is relatively scanned along the surface of the sample while maintaining a constant predetermined physical quantity between the cantilever and the surface of the sample is acquired. In the scanning probe microscope, the measurement data includes at least the first measurement data obtained by performing the first scan, and has a distribution image calculation means for calculating the first distribution image and the second distribution image. The first distribution image is at least the first measurement data, and the second distribution image is the difference between the desired data and the data behind it among the individual data of the first measurement data. Or, the display control means includes the difference data obtained by calculating the difference between the desired data and the data before the desired data, and further displays the information on the display means, and the display control means has the first distribution. It is characterized in that at least one of the image and the second distribution image is displayed.
The scanning probe microscope according to the third aspect of the present invention includes a cantilever provided with a probe that is in contact with or close to the surface of the sample, and a displacement detector that detects a signal indicating the displacement of the cantilever. Based on this, while maintaining a constant physical quantity between the cantilever and the surface of the sample, the measurement data obtained when the probe is relatively scanned along the surface of the sample is acquired. In the scanning probe microscope, the measurement data includes at least the first measurement data obtained by performing the first scan and the second measurement data obtained by performing the second scan, and the first measurement data is included. It has a distribution image calculation means for calculating a distribution image and a second distribution image, the first distribution image is at least the first measurement data, and the second distribution image is the first measurement data. It is a second distribution image including the difference data obtained by calculating the difference between the second measurement data and the second measurement data, and further has a display control means for displaying information on the display means, and the display control means is said. It is characterized in that at least one of the first distribution image and the second distribution image is displayed.
In the scanning probe microscope of the present invention, when the display control means displays both the first distribution image and the second distribution image, the measurement data and the difference data at the same position may be displayed at the same time. good.
According to this scanning probe microscope, since the first distribution image and the second distribution image at the same position are displayed at the same time, the difference between the two distribution images can be compared at the same position, and more useful information can be obtained.

Claims (7)

A cantilever provided with a probe that comes into contact with or close to the surface of the sample and a displacement detector that detects a signal indicating the displacement of the cantilever are provided, and the cantilever is located between the cantilever and the surface of the sample based on the signal. In a scanning probe microscope that acquires measurement data obtained when the probe is relatively scanned along the surface of the sample while maintaining a constant physical quantity.
The one-dimensional or two-dimensional first distribution image of the measurement data and the measurement data are arranged in the order of the scanning direction, and arranged in a direction intersecting the scanning direction at intervals for each scan and arranged in two dimensions. A distribution image calculation means for calculating a one-dimensional or two-dimensional second distribution image of the difference data of adjacent data at the time, and
Display control for instructing the distribution image calculation means to calculate one or both of the first distribution image and the second distribution image, and displaying the calculated distribution image on a predetermined display means. Means and
A scanning probe microscope characterized by being further equipped with. The scanning probe microscope according to claim 1, wherein the display control means simultaneously displays the measurement data and the difference data at the same position when displaying both the first distribution image and the second distribution image. Further provided with a calculation direction designating means for designating the calculation direction of the data when calculating the first distribution image and the second distribution image.
The distribution image calculating means calculates a distribution image displayed on the display means among the first distribution image and the second distribution image along the calculation direction designated by the calculation direction designating means. The scanning probe microscope according to claim 1 or 2. Further provided with a deduction order specifying means for designating a deduction order of differences between adjacent data when calculating the second distribution image.
The scanning probe microscope according to any one of claims 1 to 3, wherein the distribution image calculating means calculates the second distribution image in the deduction order designated by the deduction order designating means. The display control means sequentially displays the second distribution image for each difference data along the scanning direction or the calculation direction.
The distribution image calculation means is designated when the calculation direction and / or the deduction order is designated by the calculation direction designating means and / or the deduction order designating means during the display of the second distribution image. The scanning probe microscope according to claim 3 or 4, wherein the second distribution image is calculated based on the calculation direction and / or the subtraction order. The distribution image calculation means recalculates the second distribution image based on the measurement data before the designation based on the designated calculation direction and / or the deduction order.
The scanning probe microscope according to claim 5, wherein the display control means displays both the recalculated second distribution image and the designated second distribution image. The scanning probe microscope according to any one of claims 1 to 6, wherein the display control means displays the measurement data and / or the difference data for each line in the scanning direction or the calculation direction.

Images