JP2007170861A - Scanning probe microscope device, and program for same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scanning probe microscope device capable of appropriately determining adjusting degree of sensitivity even when the inspected object has an unclear outline due to irregularity on the surface. <P>SOLUTION: The scanning probe microscope device comprises a scanning control section 24 for reciprocating and scanning a probe attached to a cantilever on the inspected object, a height control section 26 for controlling the height of the probe based on the deviation from a target value of a pressing force acting on the cantilever, a surface shape detection section 27a for detecting the surface shape on the scanning line based on the scanning positional information and height information of the probe, a deviation distribution detection section 27b for determining the deviation distribution on the scanning line, based on the scanning positional information and the deviation, a display control section 29 for overlaying and two-dimensionally displaying the deviation distribution on the approach route and back route of the reciprocating and scanning and overlaying and two-dimensionally displaying the obtained surface shapes on the approach route and back route, and an offset adjusting section 28 for offsetting the scanning positional information on the approach route and back route based on the offset amount specified by a user. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a scanning probe microscope apparatus and a program for the scanning probe microscope apparatus. More specifically, the present invention relates to a scanning probe microscope that detects the surface shape of a minute inspection object using a cantilever to which a probe is attached. It relates to the improvement of the device.

  A scanning probe microscope is known as an observation apparatus for observing the surface shape of a fine inspection object. A scanning probe microscope scans a probe (probe) attached to the tip of a cantilever (cantilever) on an inspection object, and measures the scanning position and height of the inspection object. The surface shape is detected (see, for example, Patent Document 1).

  The probe is pressed against the inspection object by the cantilever, and the height of the cantilever is feedback controlled so that the pressing force acting on the cantilever is constant. In this feedback control, the pressing force acting on the cantilever is detected based on the deflection amount and amplitude of the cantilever, and the height of the cantilever is controlled based on the deviation of the pressing force from the target value. Since the scanning position and height of the probe are obtained from the scanning position and height of the cantilever, the scanning position information and height information of the probe are obtained by scanning such a cantilever on the inspection object. Then, shape data indicating the surface shape of the inspection object is generated.

In such a scanning probe microscope, the followability and responsiveness of the probe to the unevenness of the surface of the inspection object change depending on the scanning speed of the probe, the target value for height control, and the feedback gain. For example, if the scanning speed of the probe is increased in order to shorten the generation time of the shape data, the followability of the probe is deteriorated. Therefore, it is necessary to determine the scanning speed according to desired observation accuracy. . Therefore, in the probe microscope described above, sensitivity adjustment is performed by changing the probe scanning speed, the target value of the pressing force, and the feedback gain. This sensitivity adjustment is usually performed based on an operation input by the user. For example, the degree of sensitivity adjustment is determined by looking at the screen display of the surface shape obtained by reciprocating scanning on the same scanning line. In the screen display of the surface shape, the surface shape on the scanning line obtained in each of the forward path and the backward path of the reciprocating scan is superimposed and displayed, and the user can compare the height for each scanning position between the forward path and the backward path, thereby Judging whether the adjustment is appropriate.
JP-A-5-157554

  In general, each surface shape obtained in the forward and backward passes of the reciprocating scan includes a delay in the response of the probe to the shape change of the surface of the object to be inspected, and a blur of the probe or cantilever caused by switching of the scanning direction. In many cases, a deviation occurs in the scanning direction. For this reason, the conventional scanning probe microscope apparatus as described above has a problem that when comparing the heights of the surface shapes, it is difficult to associate the forward path and the backward path, and the sensitivity adjustment is not easy. In particular, for an inspection object whose contour due to surface irregularities is not clear, the change in the surface shape becomes slow, so that the correspondence between the forward path and the backward path is extremely difficult.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a scanning probe microscope apparatus and a scanning probe microscope apparatus program that facilitate sensitivity adjustment. In particular, an object of the present invention is to provide a scanning probe microscope apparatus that can appropriately determine the degree of sensitivity adjustment even for an inspection object whose contour due to unevenness on the surface is not clear.

  The scanning probe microscope apparatus according to the first aspect of the present invention detects a pressing force acting on the cantilever, scanning means for reciprocally scanning the same scanning line by pressing a probe attached to the tip of the cantilever against the inspection object. And a height control means for controlling the height of the probe based on a deviation of the detected pressing force from a target value, and a surface shape on the scanning line based on scanning position information and height information of the probe. The surface shape detection means for detecting the deviation, the deviation distribution detection means for obtaining the deviation distribution on the scanning line based on the scanning position information and the deviation, and the surface shape obtained respectively in the forward and backward paths of the reciprocating scanning. A display control means for displaying the deviation distribution obtained in the forward path and the return path in a two-dimensional display, and displaying an offset specified by the user. Offset adjustment means for relatively offsetting the scanning position information in the forward path and the backward path based on a scanning amount, and the display control means calculates the surface shape and the deviation distribution based on the scanning position information after the offset. Configured to display.

  In this scanning probe microscope apparatus, the surface shape and deviation distribution obtained by reciprocating scanning are two-dimensionally displayed on the forward and backward paths of the reciprocating scanning, respectively, and based on the offset amount specified by the user, Scanning position information is offset. With such a configuration, the surface shape and the deviation distribution can be displayed with the offset amount changed as necessary, so that the correspondence when comparing the surface shape and the deviation distribution between the forward path and the backward path is facilitated. can do.

  In the scanning probe microscope apparatus according to the second aspect of the present invention, in addition to the above configuration, when the display control means displays the deviation distribution, the deviation sign of either the forward path or the backward path is inverted and displayed. Configured to do. According to such a configuration, when the deviation distribution is compared between the forward path and the backward path of the reciprocating scan, it becomes easier to associate the deviation for each scanning position. Even if it exists, it can be judged easily whether the adjustment degree of a sensitivity is appropriate.

  In the scanning probe microscope apparatus according to the third aspect of the present invention, in addition to the above-described configuration, the display control means simultaneously displays the surface shape and the deviation distribution on the same screen, and displays the scanning positions so as to coincide with each other. Composed. According to such a configuration, since the surface shape and the deviation distribution are displayed with the scanning positions being matched, it is easy to compare them, and it is possible to improve convenience when adjusting the offset amount and sensitivity.

  The scanning probe microscope apparatus according to the fourth aspect of the present invention includes a target value changing means for changing the target value based on a user operation in addition to the above-described configuration.

  A scanning probe microscope apparatus according to a fifth aspect of the present invention includes feedback gain changing means for changing a proportional gain and an integral gain based on a user operation, in addition to the above configuration, and the height control means includes the proportional gain and The height of the probe is feedback controlled based on the integral gain.

  A program for a scanning probe microscope apparatus according to a sixth aspect of the present invention is directed to a scanning unit that presses a probe attached to the tip of a cantilever against an object to be inspected and reciprocates on the same scanning line, and a pressing force that acts on the cantilever. A height control means for controlling the height of the probe based on the deviation of the detected pressing force from the target value, and on the scanning line based on the scanning position information and height information of the probe. A program for controlling a scanning probe microscope apparatus comprising surface shape detection means for detecting a surface shape and display control means for two-dimensionally displaying the surface shapes obtained in the forward and backward passes of the reciprocating scanning. A deviation distribution detection procedure for obtaining a deviation distribution on the scanning line based on the scanning position information and the deviation, and an offset amount designated by the user Based on the offset adjustment procedure for relatively offsetting the scanning position information in the forward path and the backward path, and the deviation distribution obtained in the forward path and the backward path are superimposed and displayed two-dimensionally, and the scanning position after the offset The computer is configured to execute a display processing procedure for displaying the surface shape and the deviation distribution based on the information.

  According to the scanning probe microscope apparatus and the scanning probe microscope apparatus program of the present invention, the offset amount can be changed as necessary to display the surface shape and the deviation distribution, so that comparison is made between the forward path and the backward path. In this case, the user can easily adjust the sensitivity, and the user can determine the degree of sensitivity adjustment by viewing these displays, thereby facilitating sensitivity adjustment. In particular, inversion display in the deviation distribution makes it easier to correlate deviations for each scanning position. Therefore, even for inspection objects whose contours due to surface irregularities are not clear, it is possible to appropriately determine the degree of sensitivity adjustment. Can do.

  FIG. 1 is a diagram showing an example of a schematic configuration of a scanning probe microscope apparatus according to an embodiment of the present invention, and shows an appearance of a microscope main body 10 to which a controller 20 is connected. The scanning probe microscope apparatus 100 according to the present embodiment is an observation apparatus that observes the surface shape of an object to be inspected by scanning a probe. From the microscope main body 10, the controller 20, and the monitor 30. Become.

  In this embodiment, a microscope apparatus including an atomic force microscope (AFM) 5 will be described as an example of an SPM (Scanning Probe Microscope). It may be a microscope apparatus equipped with a microscope, for example, a scanning tunneling microscope (STM). The AFM is a microscope that uses an atomic force acting between atoms at the tip of the probe and atoms on the surface of the inspection object. In contrast, the STM is a microscope that uses a conductive sample as an inspection target and uses a tunnel current flowing between the probe and the inspection object when the probe is brought close to the sample surface.

  The microscope main body 10 generates a side view image viewed from the side of the cantilever, a mounting table 11 on which an inspection object is mounted, an AFM 5 having a cantilever holding unit 12, an optical microscope 13 that generates a microscope image. A side view camera 14 and a housing 1a for housing these are provided.

  The mounting table 11 is a table having a horizontal mounting surface, and is used for positioning an inspection object. The cantilever holding part 12 is a holder that holds the cantilever in a detachable manner.

  The optical microscope 13 is an imaging device that images an inspection object on the mounting table 11 and generates a microscope image. Here, it is assumed that light from the inspection object is observed using the optical axis conversion mirror 15 and a microscope image is generated as a photographed image viewed from behind the cantilever, that is, from a position higher than the cantilever. The optical axis conversion mirror 15 is an optical element that reflects light and changes the direction of the optical axis. Such a microscope image is used for positioning the inspection object in the horizontal plane with respect to the probe.

  The side view camera 14 is an imaging device that photographs an inspection object and a cantilever arranged on the mounting table 11 and generates a captured image viewed from the side of the cantilever, that is, from the horizontal direction, as a side view image. The side view image is an image having a lower magnification than the microscope image generated by the optical microscope 13, and is used to monitor the approach between the inspection object and the probe when the inspection object is brought close to the probe. used.

  The housing 1a is provided with an opening that is used as an outlet when the inspection object is replaced, and the state inside the housing 1a can be directly seen through the opening. At the time of measurement by the AFM 5, the probe is scanned while the opening is closed by the detachable panel plate 1b. By doing so, it is possible to prevent sound, wind, light and the like from entering the inspection area near the mounting table 11, and to suppress the vibration of the air and the vibration caused by the wind from reducing the measurement accuracy of the AFM 5. can do. In particular, in the self-detecting AFM 5 that detects the deflection amount and amplitude of the cantilever based on an electric signal from the piezoelectric element, it is possible to prevent a malfunction from occurring in the operation of the piezoelectric element due to intrusion of light.

  Further, on the front panel of the housing 1a, there are adjustment knobs 2a, 2b and operation buttons 3 for adjusting the visual field position of the microscope image, and an operation button 4 for turning on / off an illumination LED for illuminating the inspection area. Has been placed.

  The controller 20 is a control device that controls each part of the microscope body 10 and performs scanning system control of the AFM 5, imaging control of the optical microscope 13, imaging control of the side view camera 14, and the like. In addition, the shape data, the microscope image, and the side view image detected by the AFM 5 are subjected to image processing and output to the monitor 30 as display data. Here, an operation mode for observing an inspection object using the AFM 5 and the optical microscope 13 (hereinafter referred to as AFM observation mode) and an operation mode for observing the inspection object using only the optical microscope 13 (hereinafter referred to as optical). It is assumed that the microscope mode is selectable.

  FIG. 2 is a perspective view showing a configuration example of the main part of the scanning probe microscope apparatus of FIG. 1, and shows the inside of the housing of the microscope main body 10. In the microscope main body 10, the scanning system 41, the movable stage 43, the drive systems 44 and 45, the optical axis conversion unit 51, the imaging unit 52, the AFM 5, the mounting table 11, the cantilever holding unit 12, the optical microscope 13, the side view camera 14, An optical axis conversion mirror 15 is disposed on the vibration isolation frame 40.

  The movable stage 43 is positioning means that changes the position of the inspection object on the mounting table 11 by being moved together with the mounting table 11. The position of the movable stage 43 in the horizontal plane (xy plane) is changed by controlling the drive system 44, and the position in the vertical direction (z-axis direction) is changed by controlling the drive system 45. By changing the position of the movable stage 43 in the horizontal plane, the area that can be scanned by the AFM 5 can be changed. Further, by moving the movable stage 43 in the vertical direction, it is possible to bring the inspection object closer to the probe or away from the probe.

  Further, it is assumed that the approaching operation when the movable stage 43 is raised to bring the inspection object close to the probe is performed in two stages. In other words, it is divided into a manual approach based on user operation and an automatic approach in which the inspection object is further moved closer to the probe and stopped based on the deflection amount and amplitude while monitoring the deflection amount and amplitude of the cantilever. .

  The AFM 5 is suspended by an L-shaped arm portion 40a (a part of the anti-vibration frame 40) in cross section by the xy plane and the yz plane, and the cantilever holding portion 12 is opposed to the mounting surface of the mounting table 11. Are arranged. In this AFM 5, by controlling the scanning system 41, the position of the cantilever holding portion 12 in the height direction (z-axis direction) is adjusted, and an operation of scanning in the horizontal direction is performed. Here, it is assumed that the scanning system 41 is driven by three voice coil motors (VCM) 42. The voice coil motor 42 is a linear motor that converts electric energy into linear motion. Each voice coil motor 42 can independently change the position of the cantilever in each of the x, y, and z axial directions.

  The optical microscope 13 is disposed on the side of the AFM 5, and generates a microscope image by reflecting light from the inspection object with the optical axis conversion mirror 15. The optical axis conversion mirror 15 is disposed in the vicinity of the cantilever so as to face the objective lens of the optical microscope 13. Light from the inspection object is incident on the objective lens via the optical axis conversion mirror 15, and the optical axis is bent at a substantially right angle by the optical axis conversion unit 51 and output to the imaging unit 52.

  Here, it is assumed that the cantilever is disposed so as to protrude from the cantilever holding portion 12 in the x-axis direction, and the probe at the tip of the cantilever is positioned at the center of the mounting table 11 (circular).

  FIG. 3 is a block diagram showing a configuration example of the main part of the scanning probe microscope apparatus of FIG. 1, and shows a functional configuration of the controller 20. The controller 20 includes an operation input unit 21, a sensitivity adjustment unit 22, a scanning information storage unit 23, a scanning control unit 24, a height control information storage unit 25, a height control unit 26, a surface shape detection unit 27a, and a deviation distribution detection unit. 27b, an offset adjustment unit 28, and a display control unit 29.

  The scanning control unit 24 performs an operation of controlling the scanning system 41 to scan the probe. The scanning of the probe is performed based on the scanning information stored in the scanning information storage unit 23. Specifically, the scanning range, resolution, scanning speed 23a, and the like of the probe are stored in the scanning information storage unit 23 as scanning information in a rewritable manner, and the position in the horizontal plane is controlled according to these scanning information. In sensitivity adjustment, an operation of reciprocating scanning on the same scanning line (reciprocal scanning) is performed, and scanning position information of the probe is output.

  The height controller 26 performs an operation of controlling the scanning system 41 and adjusting the height of the probe. This height control of the probe is performed by detecting the pressing force acting on the cantilever. The probe is pressed against the inspection object by the cantilever, and the height of the probe is feedback controlled so that the pressing force acting on the cantilever is constant. Since the deflection amount (distortion) and amplitude of the cantilever change according to the applied pressing force, the pressing force can be determined based on the deflection amount and amplitude.

  Here, the cantilever is composed of a piezoelectric element, and the pressing force acting on the cantilever is detected by obtaining the amount of deflection and the amplitude based on the electrical signal from the piezoelectric element. The feedback control of the probe height is performed based on the deviation of the pressing force detected in this way from the target value, the proportional gain (P gain) and the integral gain (I gain). Is output.

  In the height control information storage unit 25, these feedback gains and target values (hereinafter referred to as force references) are stored as rewritable feedback parameters 25a.

  Here, an operation mode in which the surface shape is measured in a state where the cantilever is vibrated at a constant frequency, a so-called damping force mode (DFM), and an operation mode in which the probe is brought into contact with the inspection object (contact mode) Is selectable. In DFM, the inspection object and the probe are brought close to each other while vibrating the cantilever at the resonance frequency peculiar to the cantilever, and the height of the probe is based on changes in amplitude, phase, and frequency generated when the inspection object and the probe are brought close to each other. Is controlled.

  The surface shape detection unit 27a performs an operation of detecting the surface shape on the scanning line based on the scanning position information and height information of the probe. This surface shape is shape data when the inspection object is cut by the scanning line, and is composed of height information for each scanning position.

  The deviation distribution detection unit 27b performs an operation of detecting a deviation distribution on the scanning line based on the scanning position information of the probe and the deviation. This deviation distribution is data indicating a deviation for defining a control amount in the height control of the probe for each scanning position, and corresponds to a change rate distribution of the height of the probe.

  The operation input unit 21 is a user interface that generates an input signal based on a user operation. The sensitivity adjustment unit 22 is a sensitivity changing unit that changes the probe scanning speed 23 a and the feedback parameter 25 a based on an input signal from the operation input unit 21.

  The offset adjustment unit 28 performs processing to relatively offset the scanning position information in the forward and backward strokes based on the offset amount designated by the user.

  The display control unit 29 performs an operation of displaying the surface shape detected by the surface shape detection unit 27a and the deviation distribution detected by the deviation distribution detection unit 27b on the screen 30. Specifically, the surface shapes obtained in the forward path and the backward path of the reciprocating scanning are displayed in a two-dimensional manner, and the deviation distributions obtained in the forward path and the return path are displayed in a two-dimensional manner.

  When displaying the deviation distributions in a superimposed manner, select either the reverse display mode for displaying the deviation distribution of either the forward path or the return path with the sign of the deviation inverted and the normal display mode for displaying the deviation distribution without being inverted. be able to. Here, it is assumed that the sign inversion is performed for the return path in the reverse display mode.

  The display control unit 29 displays the surface shape and the deviation distribution based on the scanning position information after the offset by the offset adjustment unit 28. Here, it is assumed that offset adjustment is performed by shifting the scanning position for the return path, and the display position of the surface shape and the deviation distribution is changed between the forward path and the return path.

<AFM observation>
Steps S101 to S110 in FIG. 4 are flowcharts showing an example of the operation in the scanning probe microscope apparatus in FIG. 1, and show the procedure of the measurement operation in the AFM observation mode. In the AFM observation mode, first, a selection screen for selecting the operation mode of the AFM 5 is displayed on the monitor 30, and a message for prompting the user to attach the cantilever is arranged (step S101).

  Next, the visual field position of the optical microscope 13 is adjusted by operating the adjustment knobs 2a and 2b so that the probe of the cantilever is at the center of the microscope image (step S102). When the adjustment of the visual field position is completed, an initialization process for detecting the resonance frequency of the cantilever and starting the vibration of the cantilever at the resonance frequency is performed (step S103).

  Next, the side view image is displayed together with the microscope image on the monitor 31, and the manual approach of the probe based on the user operation is started (step S104). When this manual approach is completed, the position of the movable stage 43 in the horizontal plane is adjusted to determine the position of the area in which the AFM 5 can be scanned (step S105).

  When the designation of the scanning range by the user operation for the scanable area of the AFM 5 is completed, the automatic probe approach is started (steps S106 to S108). When this automatic approach is completed, scanning by the AFM 5 is started and shape data is generated (steps S109 and S110).

  5 to 9 are diagrams showing an example of the operation of the scanning probe microscope apparatus of FIG. 1, and shows a state of the monitor screen 200 displayed on the monitor 30 in the AFM observation mode. The monitor screen 200 is a display screen that displays a microscope image taken by the optical microscope 13 and an observation result by the AFM 5. The monitor screen 200 includes a main title display area 201, a tab display area 202, a main image display area 203, a subtitle display area 204, an observation mode display area 205, an operation procedure display area 206, a message display area 207, and a procedure detail display area 208. And a user operation display area 209.

  The main title display area 201 is a display area for displaying a character string indicating the operating state, and is arranged at the top of the monitor screen 200. The tab display area 202 is a display area for displaying character strings indicating image data being processed as tabs in the order of processing. The main image display area 203 is a display area for displaying a microscope image being photographed and an observation result by the AFM 5.

  The subtitle display area 204 is a display area for displaying a character string indicating the subtitle. The observation mode display area 205 is a display area for displaying an observation mode, and selection boxes for an AFM observation mode and an optical microscope mode are arranged. This selection box can be operated and selected using a pointing device such as a mouse, and the observation mode can be switched to either the AFM mode or the optical microscope mode.

  The operation procedure display area 206 is a display area for schematically displaying an operation procedure at the time of AFM observation. Specifically, an icon indicating each operation procedure from “cantilever attachment” to “scan” and an icon indicating a stop button for stopping the scan are arranged. The operation procedure can be executed by selecting these icons. Here, it is assumed that the operation-selected icon is focused and displayed, for example, highlighted, so that the operation procedure being executed can be determined.

  The message display area 207 is a display area for displaying a message regarding the operation procedure being executed. The procedure detail display area 208 is a display area for displaying a character string indicating details of the operation procedure being executed. The user operation display area 209 is a display area for displaying user operation selection targets and operation targets regarding the operation procedure being executed. Specifically, a selection box for designating a measurement mode, an operation button for shifting to the next operation procedure, a side view image in manual approach, an operation button for moving the movable stage 43, a scanning range An input box or the like for designating is arranged in the user operation display area 209 according to the operation state. The display areas 206 to 209 are arranged on the right side of the main image display area 203 in the monitor screen 200.

  FIG. 5 shows a screen when the cantilever is mounted, and a microscope image is displayed in the main image display area 203. On the monitor screen 200, the state of the cantilever 12a attached to the cantilever holding portion 12 and the temperature compensation protruding portion 12b are displayed as a microscope image. In addition, positioning straight lines A1 and A2 intersecting at the center of the main image display area 203 are displayed.

  After the cantilever 12a is mounted, the user operates the adjustment knobs 2a and 2b to adjust the visual field position of the microscope image. Specifically, the visual field position is adjusted so that the probe of the cantilever 12a overlaps the intersection of the straight lines A1 and A2. After the adjustment of the visual field position, the operation can be shifted to the next operation procedure by operating the “next” button 209a or selecting the operation procedure “manual approach”.

  FIG. 6 shows a screen when the height of the movable stage 43 is adjusted by a manual approach, and a side view image 210 is displayed in the user operation display area 209. On the monitor screen 200, the focus position of the optical microscope 13 is switched from the cantilever 12a to a predetermined position on the inspection object side, and the state around the cantilever 12a is displayed as a side view image 210.

  In the user operation display area 209 on the monitor screen 200, in addition to the side view image 210, operation buttons 211 a to 211 d and 212 for moving the movable stage 43 and a shooting magnification of the side view camera 14 are selected. A selection box is placed. Here, it is assumed that the operation buttons 211a to 211d are arranged on the right side of the side view image 210, and two or three stages of movement speeds can be selected with respect to the movement speed when the movable stage 43 is raised or lowered.

  Specifically, by operating the operation buttons 211a and 211b, the movable stage 43 is raised, and the inspection object can be moved to the cantilever 12a side. At that time, the operation button 211a can be moved faster than the operation button 211b. Further, by operating the operation buttons 211c and 211d, the movable stage 43 is lowered, and the inspection object can be moved to the side opposite to the cantilever 12a. At this time, the operation button 211d can be moved faster than the operation button 211c.

  The operation button 212 is an operation button for moving the movable stage 43 to the lowest point in the movable range and retracting the probe. Further, as the shooting magnification of the side view camera 14, a shooting mode with a normal magnification (here, displayed as “× 1”) and a shooting mode with a higher magnification than the normal magnification (here, displayed as “× 2”). Either can be selected. Here, it is assumed that the shooting magnification by the side view camera 14 is increased by performing image processing on the captured image. After the adjustment of the height of the movable stage 43 is completed, if the “OK” button 213 is operated or the operation procedure “horizontal position adjustment” is selected, the next operation procedure can be entered.

  FIG. 7 shows a screen for adjusting the horizontal position of the movable stage 43, and icons for adjustment are displayed in the user operation display area 209. Specifically, an icon for adjusting the optical system of the optical microscope 13, a photographing button 220, a display area 221 graphically showing the movable range and probe position of the movable stage 43, and the horizontal position of the movable stage 43 are adjusted. The operation buttons 222 are arranged.

  Here, it is assumed that a microscope image is displayed by zooming up or moving the focal position by operating an icon. The shooting button 220 is an operation button for taking an image displayed in the main image display area 203 into a memory as a still image.

  In the display area 221, the movable range of the movable stage 43 in the horizontal plane is displayed as a probe position 221 a relative to the movable stage 43. The position of the movable stage 43 in the horizontal plane can be adjusted by operating the operation button 222 to move the probe position 221a back and forth and right and left. After the horizontal position adjustment of the movable stage 43 is completed, if the “OK” button 213 is operated or the operation procedure “scan setting” is selected, the next operation procedure can be entered.

  FIG. 8 shows a screen at the time of scan setting, and input boxes 231 to 234 for specifying a scanning range and a sensitivity adjustment button 235 for adjusting the sensitivity of the AFM 5 are arranged in the user operation display area 209. Yes. On the monitor screen 200, a rectangular frame A3 that defines an area that can be scanned by the AFM 5 is displayed in the main image display area 203 so as to overlap the microscope image. The user can designate a rectangular area A4 as the probe scanning range in the rectangular frame A3.

  Here, for the rectangular area A4, the scanning range of the probe is determined by designating the position coordinates of the center point, the vertical and horizontal scanning range, the aspect ratio (vertical and horizontal ratio), and the angle. After the setting of the scanning range of the probe as described above, if the operation procedure “scan” is selected, scanning by the AFM 5 can be started.

  FIG. 9 shows a screen upon completion of scanning, and the observation result by the AFM 5 is displayed in the main image display area 203. In this example, as an observation result by the AFM 5, a line profile indicating a height difference between a height image B1 indicating a change in height on the surface of the inspection object as a change in brightness and a cross section of the inspection object cut along a predetermined cutting line A5. B2 is displayed.

  The height image B1 is generated by converting shape data obtained by scanning the rectangular area A4 into luminance data for each pixel. In the height image B1, the height difference (unevenness) on the surface of the inspection object is represented as a luminance difference. Specifically, the higher the height, the brighter.

<Sensitivity adjustment>
Steps S201 to S209 in FIG. 10 are flowcharts showing an example of the operation in the scanning probe microscope apparatus in FIG. 1, and show processing procedures during sensitivity adjustment. First, when a scanning position is designated by the user, a reciprocating scan that reciprocally scans the scanning line within a predetermined range is started (steps S201 and S202). When this reciprocating scan is completed, the surface shape and deviation distribution are detected from the scanning position information, height information, and deviation information, and are displayed on the screen of the monitor 30 (steps S203 and S204).

  At this time, if the user selects and designates the deviation distribution inversion display mode, the process of inverting the sign of the deviation is performed for the return path (steps S205 and S208). Next, the user looks at the surface shape and deviation distribution on the monitor 30 to determine the deviation in the scanning direction between the forward path and the backward path, and performs an operation input for designating the offset amount. Based on this operation input, the scanning position information is offset, and the offset surface shape and deviation distribution are displayed (step S206).

  Next, the user determines the degree of sensitivity adjustment by looking at the offset surface shape and deviation distribution. If the sensitivity needs to be changed, the user inputs an operation for changing the sensitivity. Sensitivity adjustment is performed based on this operation input (steps S207 and S209), and the processing procedure from step S202 to step S206 is repeated. If the sensitivity adjustment level is appropriate and it is not necessary to change the sensitivity again, this process ends.

  FIGS. 11A to 11C are diagrams showing an example of the operation in the scanning probe microscope apparatus of FIG. 1, schematically showing the surface shape displayed on the monitor 30 when the reciprocating scan is completed. Yes. 11A and 11B show a case where the sensitivity of the AFM 5 is not appropriate, and FIG. 11C shows a case where the offset amount C2 is adjusted to optimize the sensitivity. Yes.

  In general, when the scanning speed of the probe is large or the target value in the height control of the probe is small, the followability of the probe to the unevenness of the surface of the inspection object is lowered, and the falling portion C1 of the surface shape or the like. Rounding occurs. (A) shows an example in which the falling portion C1 is rounded in the forward and backward paths of the reciprocating scan.

  Even if the scanning speed of the probe is low, if the target value is large, or if the proportional gain or integral gain in the probe height control is large, overshoot occurs at the time of rising, and the rising portion of the surface shape Oscillation noise C3 occurs. (B) shows an example in which oscillation noise C3 occurs at the rising portion of the forward path and the backward path.

  The user sees the screen display of such shape data and determines the degree of sensitivity adjustment. At this time, if the offset adjustment is performed in advance so that the offset amount C2 between the forward path and the backward path is small, it is easy to determine whether or not the sensitivity is appropriate.

  12 (a) and 12 (b) are diagrams showing an example of the operation in the scanning probe microscope apparatus of FIG. 1, and a deviation distribution corresponding to the surface shape of FIG. 11 is schematically shown. FIG. 12A shows a case where the sensitivity of the AFM 5 is not appropriate, and FIG. 12B shows a case where the offset amount C2 is adjusted to optimize the sensitivity.

  In this deviation distribution, a convex portion having a maximum point is generated on the positive region side of the deviation corresponding to the rising of the surface shape, and a convex portion having a minimum point is generated on the negative region side corresponding to the falling. According to such a deviation distribution, only a portion where a large change in the surface shape occurs is extracted as a convex portion, so that it is easy to perform offset adjustment for the forward path and the backward path. Therefore, if the offset amount C2 is adjusted based on such a deviation distribution and the sensitivity is adjusted based on the shape data after the offset adjustment, it is possible to appropriately determine the degree of sensitivity adjustment.

  Specifically, with respect to the deviation distribution, the offset amount C2 is adjusted so that the position of the convex portion in the scanning direction matches between the forward path and the backward path.

  FIG. 13 is a diagram showing an example of the operation in the scanning probe microscope apparatus of FIG. 1, and schematically shows a deviation distribution in the reverse display mode. In this example, the sign of the deviation is inverted for the deviation distribution on the return path. If the deviation distribution is displayed in this way, it is possible to determine whether or not the position correspondence in the scanning direction is appropriate depending on the overlap of the deviation distribution between the forward path and the backward path. Is even easier.

  14 to 16 are diagrams showing an example of the operation in the scanning probe microscope apparatus of FIG. 1, and shows the state of the monitor screen 200 during sensitivity adjustment. FIG. 14 shows a screen when setting the reciprocating scan. In the monitor screen 200, a microscope image is displayed in the main image display area 203, and an input box 241 for designating a scanning position for reciprocal scanning is arranged in the user operation display area 209.

  Here, if the position coordinate of the center point is input as the scanning position of the reciprocating scan, the scanning line D1 defined by the position coordinate is displayed in the rectangular frame A3. If the “reciprocating scan” button 242 is operated after designating the scanning position, the reciprocating scan with respect to the scanning line D1 can be started.

  FIG. 15 shows a screen when the reciprocating scan is completed, and the surface shape and deviation distribution obtained by the reciprocating scan are simultaneously displayed on the same screen. In the monitor screen 200, the main image display area is divided into upper and lower parts, a title 311 and a surface shape 312 are displayed in the upper area, and a title 321 and a deviation distribution 322 are displayed in the lower area.

  Further, on the right side of the main image display area, a display area 323 in which messages and schematic diagrams are arranged, display areas 330 and 331 relating to sensitivity setting, and display areas 340 and 341 relating to offset setting are arranged.

  The surface shape 312 is displayed with the left-right direction as the scanning direction (y-axis direction) and the up-down direction as the height direction (z-axis direction), and the forward waveform E1 and the backward waveform E2 each having a height for each scanning position are overlapped. Has been placed.

  The deviation distribution 322 is displayed with the surface shape 312 and the scanning position coincident with each other, and the forward waveform E3 and the backward waveform E4, which are deviations for each scanning position, are arranged in an overlapping manner. That is, the surface shape 312 and the deviation distribution 322 are displayed by matching the forward and backward scanning start positions, the scanning end positions, and the display scale in the scanning direction. In this deviation distribution 322, the zero point of deviation is displayed for the forward waveform E3 and the backward waveform E4.

  In the display area 323, a message or a schematic diagram showing a guideline for sensitivity adjustment, and a selection box 324 for selecting reverse display of the deviation distribution 322 are arranged. The sensitivity of the AFM 5 can be determined to be appropriate if the forward waveform and the return waveform of the surface shape match, or if the forward waveform and the return waveform of the deviation distribution are subject to vertical movement.

  In the sensitivity setting display area 331, an icon 332 for designating the scanning speed of the probe, an input box 333 for designating a target value (force reference) for height control, and an input for designating a feedback gain are provided. Boxes 334 and 335 are disposed.

  In the offset setting display area 341, an icon 342 for adjusting the offset amount between the forward path and the backward path is arranged for the surface shape 312 and the deviation distribution 322. In this example, if the operation lever of the icon 342 is moved to the right, the return waveforms E2 and E4 can be moved to the right, and if the operation lever is moved to the left, the return waveforms E2 and E4 are moved to the left. Can be made.

  FIG. 16 shows the surface shape 312 and the deviation distribution 322 after adjusting the offset amount. The monitor screen 200 displays a surface shape 312 and a deviation distribution 322 that have been offset adjusted by moving the backward waveforms E2 and E4 to the left. The user determines the degree of sensitivity adjustment by looking at the shape data that has been offset adjusted in this way, and adjusts the sensitivity as necessary. When the scanning speed, the force reference, and the feedback gain are changed as sensitivity adjustment, a reciprocating scan can be started by operating the “rescan” button 350. When this reciprocating scan is completed, the surface shape and the deviation distribution obtained by the rescan are displayed on the monitor screen 200.

  According to the present embodiment, the surface shape and the deviation distribution can be displayed with the offset amount changed as necessary, so that the correspondence when comparing the surface shape and the deviation distribution between the forward path and the backward path is made. Can be facilitated. In addition, since the deviation distribution is displayed in reverse for the deviation distribution, it becomes easier to correlate the deviation for each scanning position. Therefore, even if the inspection target is not clear due to surface irregularities, the degree of sensitivity adjustment is appropriate. It can be easily determined whether or not.

  In the present embodiment, an example has been described in which the offset is adjusted between the forward path and the backward path by shifting the scanning position for the backward path of the reciprocating scan, but the present invention is not limited to this. The offset may be adjusted by shifting the scanning position for the forward path. In the present embodiment, an example in which the sign of deviation is reversed for the return path in the reverse display mode has been described, but the sign of deviation may be inverted for the forward path.

  In the present embodiment, an example in which the movable stage 43 is moved to bring the inspection target close to the probe has been described, but the present invention is not limited to this. Other configurations may be used as long as the object to be inspected and the probe are brought closer by relatively moving the mounting table 11 and the cantilever 12a. For example, the probe can be moved closer to the inspection object by moving the cantilever.

1 is a diagram illustrating an example of a schematic configuration of a scanning probe microscope apparatus according to an embodiment of the present invention, and illustrates an appearance of a microscope main body 10. FIG. FIG. 2 is a perspective view showing a configuration example of a main part of the scanning probe microscope apparatus of FIG. FIG. 2 is a block diagram illustrating a configuration example of a main part of the scanning probe microscope apparatus of FIG. 1, in which a functional configuration of a controller 20 is illustrated. 2 is a flowchart showing an example of an operation in the scanning probe microscope apparatus of FIG. 1, showing a processing procedure of a measurement operation in an AFM observation mode. It is the figure which showed an example of the operation | movement in the scanning probe microscope apparatus of FIG. 1, and the screen at the time of cantilever mounting | wearing is shown. It is the figure which showed an example of the operation | movement in the scanning probe microscope apparatus of FIG. 1, and the screen at the time of the height adjustment of the movable stage 43 by a manual approach is shown. FIG. 2 is a diagram showing an example of the operation in the scanning probe microscope apparatus of FIG. 1, and shows a screen when the horizontal position of the movable stage 43 is adjusted. It is the figure which showed an example of the operation | movement in the scanning probe microscope apparatus of FIG. 1, and the screen at the time of a scan setting is shown. It is the figure which showed an example of the operation | movement in the scanning probe microscope apparatus of FIG. 1, and the screen at the time of completion of a scan is shown. It is the flowchart which showed an example of the operation | movement in the scanning probe microscope apparatus of FIG. 1, and the process sequence at the time of sensitivity adjustment is shown. It is the figure which showed an example of the operation | movement in the scanning probe microscope apparatus of FIG. 1, and the surface shape displayed on the monitor 30 at the time of completion of a reciprocating scan is typically shown. FIG. 12 is a diagram showing an example of the operation in the scanning probe microscope apparatus of FIG. 1, and schematically shows a deviation distribution corresponding to the surface shape of FIG. 11. It is the figure which showed an example of the operation | movement in the scanning probe microscope apparatus of FIG. 1, and the deviation distribution in reverse display mode is typically shown. It is the figure which showed an example of the operation | movement in the scanning probe microscope apparatus of FIG. 1, and the screen at the time of a reciprocating scan setting is shown. It is the figure which showed an example of the operation | movement in the scanning probe microscope apparatus of FIG. 1, and the screen at the time of completion of a reciprocating scan is shown. FIG. 2 is a diagram showing an example of an operation in the scanning probe microscope apparatus of FIG. 1, and shows a surface shape 312 and a deviation distribution 322 after adjusting an offset amount.

Explanation of symbols

1a Housings 2a, 2b Adjustment knobs 3, 4 Operation buttons 5 AFM
DESCRIPTION OF SYMBOLS 10 Microscope main body 11 Mounting stand 12 Cantilever holding part 12a Cantilever 13 Optical microscope 14 Side view camera 15 Optical axis conversion mirror 20 Controller 21 Operation input part 22 Sensitivity adjustment part 23 Scan information storage part 24 Scan control part 25 Height control information storage Unit 26 height control unit 27a surface shape detection unit 27b deviation distribution detection unit 28 offset adjustment unit 29 display control unit 30 monitor 40 anti-vibration frame 40a arm unit 41 scanning system 42 voice coil motor 43 movable stage 44, 45 drive system 51 light Axis conversion unit 52 Imaging unit 100 Scanning probe microscope apparatus

Claims (6)

Scanning means for pressing the probe attached to the tip of the cantilever against the inspection object and reciprocatingly scanning on the same scanning line;
A height control means for detecting a pressing force acting on the cantilever and controlling the height of the probe based on a deviation of the detected pressing force from a target value;
Surface shape detecting means for detecting the surface shape on the scanning line based on the scanning position information and height information of the probe;
Deviation distribution detecting means for obtaining a deviation distribution on the scanning line based on the scanning position information and the deviation;
Display control means for two-dimensionally displaying the surface shapes obtained in the forward path and the backward path of the reciprocating scanning, and displaying the deviation distributions obtained in the forward path and the backward path in a two-dimensional manner;
An offset adjusting means for relatively offsetting the scanning position information in the forward path and the backward path based on an offset amount designated by a user;
The scanning control microscope apparatus, wherein the display control means displays a surface shape and a deviation distribution based on the scanning position information after the offset.   2. The scanning probe microscope apparatus according to claim 1, wherein the display control means displays the deviation distribution by inverting the sign of the deviation for either the forward path or the backward path when displaying the deviation distribution.   2. The scanning probe microscope apparatus according to claim 1, wherein the display control means simultaneously displays the surface shape and the deviation distribution on the same screen, and displays the scanning positions at the same position.   The scanning probe microscope apparatus according to claim 1, further comprising target value changing means for changing the target value based on a user operation. Provided with feedback gain changing means for changing the proportional gain and the integral gain based on a user operation,
2. The scanning probe microscope apparatus according to claim 1, wherein the height control means feedback-controls the height of the probe based on the proportional gain and integral gain. A scanning means that presses the probe attached to the tip of the cantilever against the object to be inspected, and reciprocally scans on the same scanning line, detects the pressing force acting on the cantilever, and based on the deviation of the detected pressing force from the target value Height control means for controlling the height of the probe, surface shape detection means for detecting the surface shape on the scanning line based on scanning position information and height information of the probe, and reciprocal scanning. A program for controlling a scanning probe microscope apparatus comprising display control means for two-dimensionally displaying the surface shapes obtained in the forward path and the return path, respectively.
A deviation distribution detection procedure for obtaining a deviation distribution on the scanning line based on the scanning position information and the deviation;
An offset adjustment procedure for relatively offsetting the scanning position information in the forward path and the backward path based on an offset amount designated by the user;
Causing the computer to execute a display processing procedure for displaying the surface shape and the deviation distribution on the basis of the scanning position information after the offset while superimposing the deviation distributions obtained in the forward path and the backward path in a two-dimensional display. A program for a scanning probe microscope apparatus.

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