JP2011252764A - Atomic force microscope and cantilever support of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an atomic force microscope which can precisely detect interaction quantity due to interatomic force between a cantilever and a sample with a measurement method using light such as an optical lever method, even when the cantilever is driven in high speed in the Z direction, and to provide a cantilever support of the atomic force microscope.SOLUTION: An atomic force microscope 100 comprises: a cantilever support 13 for supporting a cantilever 14; and a Z scanner 12 for driving the cantilever support 13 with a height direction as a driving direction. The cantilever support 13 comprises: a cantilever attachment part which projects in a direction perpendicular to the driving direction of the Z scanner 12; and a balance projection part which projects in a direction opposite to the projecting direction of the cantilever attachment part.

Description

  The present invention relates to an atomic force microscope and its cantilever support. The present invention is suitably applied to a high-speed atomic force microscope that detects displacement of a cantilever by a measuring method using light such as an optical lever method and its cantilever support.

  An atomic force microscope (AFM) is a microscope that acquires information on the surface of a sample by detecting the amount of interaction caused by the atomic force between the sample and a cantilever having a probe at the tip. is there. Since the cantilever bends due to the interaction, the atomic force microscope detects this bend amount as an interaction amount (in the case of DC mode), or the amplitude change amount, phase change amount of the cantilever vibration due to the bend of the cantilever, A frequency change amount is detected as an interaction amount (in the case of AC mode).

  In the atomic force microscope, the amount of interaction is changed while the relative position of the cantilever and the sample in the sample surface direction (XY direction) is changed, that is, while the cantilever is scanned relative to the sample in the sample surface direction. The cantilever height (Z-direction position) or the sample stage height (Z-direction position) is feedback controlled so that the height of each point on the surface of the sample is controlled based on the amount of control. Get information on sheath properties.

  In such an atomic force microscope, methods for moving the cantilever relative to the sample in the XYZ directions include a stage scanning method for moving the sample stage side and a tip scanning method for moving the cantilever side. is there. Since the tip scan method only needs to move a cantilever having a small mass, it can be applied even when the sample is large, and has an advantage that the relative movement between the cantilever and the sample can be speeded up.

  In the chip scan method, actuators are used in the three directions of X, Y, and Z, respectively. For example, a piezoelectric actuator is used as the actuator. Generally, since the scanning frequency in the Z direction is the highest among the three directions of X, Y, and Z, the Z scanning actuator is provided at the end. That is, a cantilever is attached to a Z scanning actuator via a cantilever supporting jig, and the cantilever supported by the jig is driven in the X direction (or Y direction) together with the Z scanning actuator. The actuator is provided, and the entire cantilever, the jig holding the cantilever, the Z scanning actuator holding the jig, and the X scanning (or Y scanning) actuator are driven in the Y direction (or X direction). A Y-scanning (or X-scanning) actuator is provided.

  In a conventional atomic force microscope, an optical lever method or the like is used in which a cantilever is irradiated with a laser beam, its reflected light is detected, and a displacement due to bending of the cantilever is measured. For this reason, in the tip-scan type atomic force microscope, the cantilever needs to protrude outward in the XY plane direction from the Z scanning actuator so that the laser beam is not blocked by the Z scanning actuator.

  FIG. 9 is a view showing a conventional cantilever attached to a Z scanning actuator. The cantilever 1 is attached to a Z scanning piezo actuator 3 via a jig 2. As shown in FIG. 9, the cantilever 1 is attached to the lower surface of the tip portion 2 a of the jig 2 such that the upper surface 1 a slightly protrudes from the tip portion 2 a of the jig 2. Thus, the laser beam is applied to the upper surface 1a of the cantilever 1, and the laser beam reflected from the upper surface 1a is detected by a sensor such as a two-divided photodiode, thereby detecting the displacement in the Z direction due to the bending of the cantilever 1.

  As shown in FIG. 9, the tip portion 2 a of the jig 2 is configured so that the laser light incident on the upper surface 1 a of the cantilever 1 and the laser light reflected from the upper surface 1 a of the cantilever 1 are not blocked by the Z scanning piezo actuator 3. It projects in the XY plane direction with respect to the Z scanning piezoelectric actuator 3. As a result, the optical path of the laser beam can be secured, and the displacement in the Z direction due to the bending of the cantilever 1 can be detected by a measuring method using light such as an optical lever method.

  The prior art as described above is described in Patent Document 1, for example.

Japanese Patent Laid-Open No. 08-083789

  However, as shown in FIG. 1, when the jig 2 is protruded in one direction with respect to the Z scanning piezo actuator 3, and the jig 2 is vibrated at high speed by the Z scanning piezo actuator 3, the jig 2 Torque is applied to 2 and the jig 2 vibrates in the Z direction with rotation within a certain range. The Z-scanning piezo actuator 3 also receives torque from the jig 2 and vibrates in the Z direction while being shaken in the protruding direction of the jig 2.

  When such an undesirable vibration of the jig 2 or the Z-scanning piezo actuator 3 occurs, the amount of deflection of the cantilever 1 due to the atomic force between the cantilever 1 and the sample in a detection method using light such as an optical lever method, The amount of vibration change cannot be detected accurately. When the cantilever 1 is driven in the Z direction at a low speed, the generation of the undesirable vibration does not cause a problem, but the undesired vibration becomes more remarkable as the cantilever 1 is driven in the Z direction at a high speed.

  FIG. 10 is a graph showing vibration characteristics when the cantilever 1 is fixed to the Z scanning piezo actuator 3 with the jig 2 shown in FIG. FIG. 10 shows the result of observing the gain and phase by vibrating the piezo actuator 3 for Z scanning with a sine wave while changing the vibration frequency with a constant amplitude. The horizontal axis of the graph of FIG. 10 is the vibration frequency (logarithmic display), the left scale on the vertical axis represents gain (dB), and the right scale represents phase (deg).

  Here, the gain on the vertical axis is the amplitude of the cantilever 1 in the Z direction. When the gain becomes zero, it means that the cantilever 1 vibrates completely in the same manner as the input vibration (vibration of the Z scanning piezo actuator). The phase of the vertical axis is the phase difference of the cantilever vibration with respect to the input vibration (vibration of the Z scanning piezo actuator). When no undesirable vibration is generated in the jig, the phase becomes −90 degrees at the frequency at which the gain reaches a peak. As can be seen from FIG. 10, when a jig having a conventional structure as shown in FIG. 9 is used, vibrations already appear at 1 kHz and 2 kHz, and vigorously vibrate above 10 kHz. The resonance frequency is about 12 kHz.

  The present invention has been made to solve the above-described problems. Even when the cantilever is driven at high speed in the Z direction, an atom between the cantilever and the sample can be obtained by a measurement method using light such as an optical lever method. It is an object of the present invention to provide an atomic force microscope and its cantilever support that can accurately detect the amount of interaction due to an interatomic force.

  In order to solve the above-described conventional problems, the atomic force microscope of the present invention includes a cantilever having a probe, and changes the relative position of the cantilever and the sample in the direction of the sample surface. An atomic force microscope that acquires information on the surface of the sample by controlling the position of the cantilever in the height direction with respect to the sample surface so that the amount of interaction caused by the atomic force is constant. The atomic force microscope further includes a cantilever support that supports the cantilever, and a Z scanner that drives the cantilever support using the height direction as a drive direction. The cantilever support has a cantilever mounting portion that protrudes in a direction orthogonal to the driving direction of the Z scanner, and a balance protrusion that protrudes in a direction opposite to the protruding direction of the cantilever mounting portion.

  Thus, since the cantilever mounting portion protrudes in a direction orthogonal to the driving direction of the Z scanner, it becomes possible to detect the displacement of the cantilever by a measuring method using light such as an optical lever method, and the balance protruding portion. Protrudes in a direction opposite to the protruding direction of the cantilever mounting portion, so even when the Z scanner is driven at a high speed, the balance protruding portion cancels the moment generated by the cantilever mounting portion in the jig and the Z scanner. The Z scanner is less likely to bend due to moment, and the amount of interaction due to the atomic force between the cantilever and the sample can be accurately detected by a measurement method using light such as an optical lever method.

  The cantilever support may have a shape and a specific gravity distribution in which moments generated by driving the Z scanner are balanced.

  With this configuration, the moment generated in the jig or the Z scanner is canceled out by the cantilever mounting portion and the balance protrusion, so that the jig or the Z scanner is not deformed by the moment.

  The cantilever support may have a plane-symmetric shape with respect to a second plane that includes the drive shaft of the Z scanner and is perpendicular to the protruding direction of the cantilever mounting portion. Further, the drive shaft of the Z scanner In addition, the first plane parallel to the protruding direction of the cantilever mounting portion may have a plane-symmetric shape.

  Thereby, the structure with which the moment by a cantilever attachment part and a balance protrusion part balances by a simple structure is realizable.

  The cantilever support is formed with an attachment surface attached to the Z scanner at the top, and a first leg extends obliquely downward from the attachment surface, and a second leg extends in a direction opposite to the first leg. The leg portion extends, the first leg portion and the second leg portion are connected by a horizontal leg portion at a lower end portion, and the cantilever attaching portion is connected to the connecting portion between the first leg portion and the horizontal leg portion. And the balance protrusion having the same shape as the cantilever mounting portion may protrude from the connecting portion between the second leg portion and the lateral leg portion.

  With this configuration, the first plane including the drive shaft of the Z scanner and parallel to the protruding direction of the cantilever mounting portion and the second plane including the drive shaft of the Z scanner and perpendicular to the protruding direction of the cantilever mounting portion. In addition, a shape that is plane-symmetric can be realized, and a lightweight jig can be configured.

  The cantilever support may have a substantially trapezoidal conical shape in which an attachment surface to be attached to the Z scanner is formed at the top.

  According to this configuration, either the first plane including the drive shaft of the Z scanner and parallel to the protruding direction of the cantilever mounting portion or the second plane including the drive shaft of the Z scanner and perpendicular to the protruding direction of the cantilever mounting portion. Also, a shape that is plane-symmetric can be realized, and in particular, any plane that includes the drive axis of the Z scanner can be realized.

  The cantilever may be attached to the cantilever attaching portion, and a dummy cantilever that is not used for acquiring information on the surface of the sample may be attached to the balance protruding portion.

  With this configuration, it is possible to realize a jig balanced on the cantilever mounting part side and the balance protrusion part side including the mass of the cantilever.

  Another aspect of the present invention is a cantilever support attached to a Z scanner of an atomic force microscope that supports a cantilever and drives the height direction of the cantilever with respect to a sample surface as a driving direction. A cantilever mounting portion that protrudes in a direction orthogonal to the driving direction and a balance protrusion that protrudes in a direction opposite to the protruding direction of the cantilever mounting portion.

  Also with this jig, as described above, the cantilever mounting portion protrudes in a direction perpendicular to the driving direction of the Z scanner, so that the displacement of the cantilever can be detected by a measurement method using light such as an optical lever method. At the same time, since the balance protrusion protrudes in the direction opposite to the protrusion direction of the cantilever mounting portion, even when the Z scanner is driven at high speed, the balance protrusion cancels the moment generated by the cantilever mounting portion in the jig or Z scanner. As a result, bending due to moment is less likely to occur in jigs and Z scanners, and the amount of interaction due to the atomic force between the cantilever and the sample can be accurately detected by a measurement method using light such as the optical lever method.

  With respect to a second plane that includes the central axis and is perpendicular to the protruding direction of the cantilever mounting portion, the surface is symmetrical with respect to the axis that coincides with the driving axis of the Z scanner when attached to the Z scanner. And a first axis parallel to the protruding direction of the cantilever mounting portion including the central axis, with the axis coincident with the drive axis of the Z scanner when attached to the Z scanner as the central axis. The plane may have a plane-symmetric shape.

  Thereby, the structure with which the moment by a cantilever attachment part and a balance protrusion part balances by a simple structure is realizable.

  In the present invention, even when the cantilever is driven at high speed in the Z direction, the amount of interaction due to the atomic force between the cantilever and the sample can be accurately detected by a measurement method using light such as an optical lever method.

Front view of the jig in the first embodiment of the present invention Side view of the jig in the first embodiment of the present invention The perspective view of the jig in the 1st Embodiment of this invention Configuration diagram of an atomic force microscope in an embodiment of the present invention The graph which shows the vibration characteristic at the time of using the jig in embodiment of this invention The top view of the jig in the 2nd Embodiment of this invention Sectional drawing of the jig in the 2nd Embodiment of this invention The perspective view of the jig in the 2nd Embodiment of this invention A perspective view of a conventional jig Graph showing vibration characteristics when using a conventional jig

  The detailed description of the present invention will be described below. The following detailed description and the accompanying drawings do not limit the invention. Instead, the scope of the invention is defined by the appended claims.

  1 to 3 are diagrams showing an embodiment of a jig employed in the atomic force microscope according to the embodiment of the present invention, and FIG. 4 is a configuration of the atomic force microscope according to the embodiment of the present invention. FIG. In the following, first, the overall configuration of the atomic force microscope will be described with reference to FIG. 4, and then the configuration of the jig will be described in detail.

  In FIG. 4, the left-right direction is the X direction, the up-down direction is the Z direction, and the direction perpendicular to the paper surface is the Y direction. The atomic force microscope 100 includes a cantilever having a probe, and the amount of interaction caused by the atomic force between the cantilever and the sample is constant while changing the relative position of the cantilever and the sample in the sample surface direction. As described above, the microscope acquires information on the surface of the sample by controlling the position of the cantilever in the height direction with respect to the sample surface.

  As shown in FIG. 4, the atomic force microscope 100 includes a microscope main body 10, a processing unit 20, and a monitor 30. The microscope main body 10 includes an XY scanner 11, a Z scanner 12, a jig 13, a cantilever 14, a dummy cantilever 14 ′, a piezo driver 15, a laser light source 16, a two-divided photodiode 17, and a sample stage 18.

  A Z scanner 12 is attached to the XY scanner 11. The XY scanner 11 moves the Z scanner 12 in the X direction and the Y direction. A jig 13 that is a support for the cantilever 14 is attached to the Z scanner 12. A cantilever 14 is attached to the jig 13. The Z scanner 12 moves the jig 13 and the cantilever 14 supported by the jig 13 in the height direction (Z direction) of the cantilever with respect to the sample surface. In other words, the jig 13 is a highly rigid member that is fixed to the Z scanner 12 and the cantilever 14 so that the cantilever 14 moves in the Z direction as the Z scanner 12 is driven in the Z direction.

  The XY scanner 11 and the Z scanner 12 are constituted by piezoelectric actuators. The piezo driver 15 supplies drive signals to the XY scanner 11 and the Z scanner 12 based on the control signal input from the processing unit 20. Each of the XY scanner 11 and the Z scanner 12 is driven according to a drive signal. The Z scanner 12 has a quadrangular prism shape that is long in the Z direction. The Z scanner 12 may have a cylindrical shape that is long in the Z direction.

  A probe is provided on the lower surface of the cantilever 14 (the probe is not shown in FIG. 4 because it is much smaller than the size of the cantilever 14). The microscope body 10 is configured such that the tip of the probe of the cantilever 14 approaches the surface of the sample S when the sample S is placed on the sample stage 18. The cantilever 14 is attached to the lower surface of the jig 13 so that the probe faces downward, and the tip portion protrudes from the tip portion of the jig 13. In addition to the cantilever 14, a dummy cantilever 14 ′ is attached to the jig 13. The dummy cantilever 14 'is a member having the same configuration as that of the cantilever 14, but is not used for acquiring information on the surface of the sample. The structure including the jig 13, the cantilever 14, and the dummy cantilever 14 'will be described later.

  The laser light source 16 is installed so as to irradiate the tip of the cantilever 14 protruding from the jig 13 with laser light. The two-divided photodiode 17 is provided on the optical path of the reflected light that is irradiated from the laser light source 16 and reflected by the cantilever 14. When the cantilever 14 is bent by the atomic force between the probe provided on the lower surface of the cantilever 14 and the sample, the reflection direction of the laser light changes, and this is detected by the two-divided photodiode 17. With this configuration, the displacement of the cantilever 14 can be measured using an optical lever method. The atomic force microscope 100 may have a configuration that employs an optical interference method as a method for measuring the displacement of the cantilever 14.

  The processing unit 20 includes an amplitude measurement unit 21, a subtracter 22, a PID calculation unit 23, and a calculation control unit 24. The amplitude measuring unit 21 is connected to the two-divided photodiode 17. The output current of the two-divided photodiode 17 is input to the amplitude measuring unit 21.

  The atomic force microscope 100 according to the present embodiment adopts an AC mode, and in measuring a sample, the Z scanner 12 is sine-wave oscillated and the amount of change caused by the atomic force between the probe of the cantilever 14 and the sample. The amplitude of the vibration added with is measured by the amplitude measuring unit 21. The amplitude measuring unit 21 measures the amplitude of the cantilever 14 based on the current output from the two-divided photodiode 17 and outputs the measured value. The output terminal of the amplitude measuring unit 21 is connected to the first input terminal (non-inverting input terminal) of the subtractor 22. The present invention can also be applied to the DC mode. In that case, the amplitude measuring unit 21 is not necessary, and the output of the two-divided photodiode 17 is input to the first input terminal of the subtractor 22.

  A constant value (set point) for control is input to the second input terminal (inverted input terminal) of the subtractor 22. In the subtracter 22, the output of the measurement value subtracter 22 output from the amplitude measurement unit 21 is connected to the input of the PID calculation unit 23. The PID calculation unit 23 calculates a control value for the Z scanner 12 by performing a proportional calculation, an integral calculation, and a differential calculation on the output of the subtractor 22. The output of the PID calculation unit 23 is connected to the input terminal of the calculation control unit 24 and the Z input terminal of the piezo driver 15.

  The calculation control unit 24 associates the control value for the Z scanner input from the PID calculation unit 23 with the XY coordinate from which the control value is obtained, thereby generating information on the height and physical properties of the sample at the XY coordinate. Information on the height and physical properties of the sample for each XY coordinate is output to the monitor 30 in the form of image information. The X output terminal and the Y output terminal of the arithmetic control unit 24 are connected to the X input terminal and the Y input terminal of the piezo driver 15, respectively. The arithmetic control unit 24 outputs control signals for the X scanner and Y scanner for scanning the cantilever 14 in the XY plane with respect to the sample S from the X output terminal and the Y output terminal, respectively.

  Next, the configuration of the jig and cantilever of this embodiment will be described in detail. In the following description, the driving direction of the Z scanner 12 passing through the center of the Z scanner 12, that is, the axis extending in the Z direction is referred to as the driving shaft of the Z scanner 12, and when the jig 13 is attached to the Z scanner 12 The axis of the jig 13 that overlaps the drive axis of the scanner 12 is referred to as the center axis of the jig 13.

  The jig 13 has a first protrusion that protrudes away from the central axis in a direction parallel to the first plane including the central axis as the distance from the attachment surface to the Z scanner 12 increases. The cantilever 14 is attached to the first protrusion. And it has the 2nd protrusion part which is parallel to the 1st plane and protrudes in the direction opposite to the 1st protrusion part. The second protrusion is for balancing with the first protrusion, and corresponds to the balance protrusion of the present invention. The jig 13 of the present embodiment has a plane-symmetric shape with respect to a second plane orthogonal to the first plane. Furthermore, the jig 13 has a plane-symmetric shape with respect to the first plane.

  Hereinafter, with reference to FIGS. 1-3, the specific shape of the jig 13 of this Embodiment is demonstrated. 1, 2, and 3 are a front view, a side view, and a perspective view of a jig according to the present embodiment, respectively. In the following description, the left-right direction in FIG. 1 is the X direction, the up-down direction is the Z direction, the left-right direction in FIG. 2 is the Y direction, and the up-down direction is the Z direction. The X, Y, and Z directions coincide with the X, Y, and Z directions in FIG.

  First, with reference to the front view of FIG. 1, the shape of the jig 13 according to the present embodiment as viewed from the front will be described. Refer to the perspective view of FIG. 3 as appropriate. The jig 13 has a symmetrical shape about the central axis C in the left and right (X direction). The jig 13 has a generally upward triangular shape. The top of the triangle is a flat attachment surface 131 that is attached to the Z scanner 12.

  The mounting surface 131 is a quadrangle in plan view, and the central axis C passes through the center of the quadrangle. From the mounting surface 131, the left leg 132 extends diagonally downward to the left, and the right leg 133 extends diagonally downward to the right. The left leg portion 132 and the right leg portion 133 are connected to each other at a lower end portion by a horizontal leg portion 134 extending in the X direction. With this configuration, a triangular structure is formed by the left leg portion 132, the right leg portion 133, and the lateral leg portion 134, and the inside of the triangle is hollow.

  A cantilever mounting portion 135 protrudes leftward from the connecting portion between the left leg portion 132 and the horizontal leg portion 134. A dummy cantilever mounting portion 136 protrudes rightward from the connecting portion between the right leg portion 133 and the horizontal leg portion 134. The lower surfaces of the cantilever mounting portion 135 and the dummy cantilever mounting portion 136 are slightly inclined downward from the horizontal.

  The mounting surface 131 of the jig 13 and the shape of the lower surface of the Z scanner 12 are the same. The jig 13 is attached to the Z scanner 12 such that the center of the attachment surface 131 coincides with the center of the lower surface of the Z scanner 12. When the jig 13 is attached to the Z scanner 12, the cantilever attachment portion 135 protrudes from the attachment surface 131 in a direction perpendicular to the drive direction of the Z scanner 12, and the cantilever attachment is performed with respect to the drive shaft of the Z scanner 12. The dummy cantilever mounting portion 136 also protrudes in the direction opposite to the protruding direction of the portion 135.

  The jig 13 is made of duralumin and has a uniform density (specific gravity distribution) as a whole. As the material of the jig 13, aluminum, PEEK resin, glass or the like may be adopted. The jig 13 can be manufactured by mold molding.

  A probe is provided on the lower surface of the tip of the cantilever 14. The upper surface of the cantilever 14 is fixed to the lower surface of the cantilever mounting portion 135 so that the lower surface having the probe faces downward. The cantilever 14 is attached such that the tip end portion having the probe protrudes from the tip end of the cantilever attachment portion 135. Thereby, the upper surface portion of the cantilever 14 protruding from the tip of the cantilever mounting portion 135 becomes the laser light reflecting surface 141.

  The dummy cantilever 14 ′ is attached to the dummy cantilever attachment portion 136 at a position and posture that is symmetrical to the cantilever 14. That is, the upper surface of the dummy cantilever 14 ′ is fixed to the lower surface of the dummy cantilever mounting portion 136 so that the front end portion protrudes from the front end of the dummy cantilever mounting portion 136. The dummy cantilever 14 ′ has the same configuration as the cantilever 14.

  Next, the shape of the jig 13 viewed from the side surface direction will be described with reference to FIG. As shown in FIG. 2, the jig 13 has a symmetrical shape in the left-right direction (Y direction) when viewed from the side surface direction (X direction). The jig 13 has a certain width in the left-right direction. The cantilever 14 and the dummy cantilever 14 'are attached to the center in the left-right direction.

  The operation of the jig 13 configured as described above will be described. The jig 13 is vibrated in the Z direction by the Z scanner 12 at a frequency of about several tens of kHz. Since the jig 13 is symmetric in both the X direction and the Y direction, the mass of the jig 13 is balanced around the central axis C. For this reason, torque is hardly applied to the jig 13 in spite of high-frequency vibration in the Z direction, and therefore bending due to such torque is difficult to occur. That is, a moment is generated in the jig 13 by high-speed driving in the Z direction, but the shape of the jig 13 is symmetrical in the X direction and the Y direction with respect to the central axis. Therefore, the jig 13 and the Z scanner 12 are less likely to be deformed.

  FIG. 5 is a graph showing vibration characteristics when the jig 13 is used. FIG. 5 corresponds to FIG. 10 and shows the gain and phase when the Z scanner 12 is sine-wave oscillated with a constant amplitude. The horizontal axis is the frequency of sinusoidal vibration (represented in logarithm), the left scale on the vertical axis is gain (dB), and the right scale on the vertical axis is phase (deg). As is apparent from FIG. 5, the resonance frequency (frequency at which the gain reaches a peak) reaches 90 kHz.

  The phase at this resonance frequency is close to -90 degrees, which indicates that the jig 13 has less resonance below the resonance frequency. Therefore, by using the jig 13 of the present embodiment, when the Z scanner 12 is driven at high speed, even if the vibration frequency is increased to about 90 kHz, undesirable vibration does not occur in the cantilever 14, and the optical lever method is used. The amount of interaction due to the atomic force between the cantilever 14 and the sample S can be accurately detected.

  As described above, according to the jig 13 of the present embodiment, the portion to which the cantilever 14 is attached protrudes from the drive shaft of the Z scanner 12 to which the jig 13 is attached in a direction orthogonal to the drive direction of the Z scanner 12. Therefore, it is possible to detect the displacement of the cantilever 14 by the optical lever method, and it has a shape protruding in the direction opposite to the protruding direction of the portion where the cantilever 14 is attached with respect to the drive shaft of the Z scanner 12. The moment generated in the jig 13 and the Z scanner 12 is canceled out by the protruding portion on the opposite side by the protruding portion on the side where the cantilever 14 is attached by driving the Z scanner 12, and as a result, the jig 13 and the Z scanner 12 are deflected by the moment. Due to the atomic force between the cantilever 14 and the sample S by the optical lever method. The interaction dose can be accurately detected.

  Further, the jig 13 of the present embodiment has a uniform specific gravity distribution and a symmetrical shape in the X and Y directions perpendicular to the drive direction of the Z scanner 12 to which the jig 13 is attached. The moments generated by driving the scanner 12 completely cancel each other, and the jig 13 and the Z scanner 12 are not deformed by the moment.

  In order to balance the moment with respect to the drive shaft of the Z scanner 12, the jig 13 does not necessarily have a protruding side on which the cantilever 14 is attached and the shape of the portion opposite to the drive shaft with respect to the drive shaft of the Z scanner 12. It is not necessary to have a symmetrical shape. That is, the jig may be configured with a shape and specific gravity distribution that cancels the moment with respect to driving in the Z direction. However, by adopting a symmetrical shape after making the specific gravity distribution uniform as in the above embodiment, it is possible to easily attach the cantilever 14 without calculating the shape and specific gravity distribution by performing complicated calculations. It is possible to realize a configuration in which the moments of the side and the portion on the opposite side with respect to the drive shaft are balanced.

  In the above embodiment, a member having the same configuration as that of the cantilever 14 is used as the dummy cantilever 14 ′, but another member having the same mass as the cantilever 14 may be used. Further, the dummy cantilever 14 'may be omitted. In particular, when the mass of the cantilever 14 or the dummy cantilever 14 ′ is negligibly small relative to the mass of the jig 13, the dummy cantilever 14 ′ may be omitted.

  Further, since the jig 13 of the present embodiment has a generally triangular shape, bending due to deformation hardly occurs, and also in this respect, undesirable vibration can be suppressed. Further, since the triangular shape is a hollow triangular shape composed of the left leg portion 132, the right leg portion 133, and the lateral leg portion 134, the jig 13 can be reduced in weight, and high-speed driving is facilitated.

  In addition, the jig of this invention is not restricted to said shape. Hereinafter, jigs according to other embodiments will be described. FIG. 6 is a plan view of a jig according to the second embodiment, and FIG. 7 is a cross-sectional view taken along line A-A ′ of FIG. 6. FIG. 8 is a perspective view of a jig according to the second embodiment. 6 and 8 show a state where the cantilever and the dummy cantilever are attached. FIG. 7 shows a jig with no cantilever and dummy cantilever attached.

  The jig 43 of the present embodiment has a generally trapezoidal cone shape. The top of the trapezoidal cone is a flat mounting surface 431 that is mounted on the Z scanner 12. The mounting surface 431 is circular in plan view. In the case of the present embodiment, the Z scanner 12 may have a cylindrical shape, and in this case, the bottom surface of the Z scanner and the circle of the mounting surface 431 can be configured to coincide with each other. In this case, the center axis C of the jig 43 passes through the center of the circle of the mounting surface 431.

  The jig 43 has a shape in which the diameter gradually increases downward from the mounting surface 431. The bottom of the jig 43 is formed in a donut shape with a bottom surface 432 inclined slightly upward from the edge toward the center, and a conical cavity portion 433 that is bent toward the mounting surface 431 is formed at the center of the bottom. Is formed.

  The jig 43 of the present embodiment has a three-dimensional shape formed by rotating the conventional jig shown in FIG. The ridgeline of the jig 43 has a shape that becomes gentler toward the bottom from the mounting surface 431 and becomes steep again near the bottom.

  The cantilever 14 and the dummy cantilever 14 ′ are attached to the jig 43. As in the above embodiment, the upper surface of the cantilever 14 is fixed to the bottom surface 432 so that the lower surface having the probe faces downward. The cantilever 14 is attached such that the tip having the probe protrudes from the tip of the bottom surface 432. As a result, the upper surface portion of the cantilever 14 protruding from the edge of the bottom surface 432 becomes the laser light reflecting surface 141. The dummy cantilever 14 ′ is attached at a position symmetrical to the cantilever 14 with respect to the central axis C.

  In the jig 43, a plane passing through the central axis C, the cantilever 14 and the dummy cantilever 14 ′ is a first plane, and a plane passing through the central axis C and perpendicular to the first plane is a second plane. Of the two parts to be divided, if the cantilever 14 is attached to the first protrusion, and the dummy cantilever 14 'is attached to the second protrusion, the first protrusion and the second protrusion Has a plane-symmetric shape with respect to the second plane. The jig 43 also has a plane-symmetric shape with respect to the first plane.

  The jig 43 is made of duralumin and has a uniform density (specific gravity distribution) as a whole. As a material of the jig 43, aluminum, PEEK resin, glass or the like may be adopted. The jig 43 can be manufactured by mold molding.

  With this configuration of the jig 43, the mass of the jig 43 is balanced around the central axis C. For this reason, despite the high-frequency vibration in the Z direction, torque is hardly applied to the jig 43, and therefore bending due to such torque is unlikely to occur. That is, a moment is generated in the jig 43 by high-speed driving in the Z direction. However, since the shape of the jig 43 is axisymmetric with respect to the central axis, this moment is balanced in the jig 43, and the jig 43 and The Z scanner 12 is less likely to be deformed.

  Shapes that are plane-symmetrical with respect to both the first plane passing through the center axis and the center of the cantilever as described above and the second plane passing through the center axis and perpendicular to the first plane are also realized in shapes other than the above. it can.

  For example, in the second embodiment, the jig 43 is configured to have a substantially trapezoidal cone shape, but the jig may be configured to have a generally trapezoidal elliptical cone shape. In this case, the cantilever 14 and the dummy cantilever 14 'can be mounted on the major axis of the bottom ellipse. Moreover, you may comprise a jig so that it may become trapezoid square pyramid shape with a substantially rectangular bottom face. In this case, the cantilever 14 and the dummy cantilever 14 'can be attached so as to be located at the center of the short side of the bottom surface. Further, the lateral leg portion 134 of the jig 13 described in the first embodiment may be omitted, and a bifurcated shape with the left leg portion 132 and the right leg portion 133 may be formed.

  In the above embodiment, the tip-scan type atomic force microscope in which the sample stage is fixed and the cantilever is moved in the three directions X, Y, and Z has been described. Since scanning at a speed as high as that in the Z direction is not required, the sample stage side may be moved for relative movement between the sample and the cantilever in the X direction, the Y direction, or both directions. Even in such an atomic force microscope, a Z scanner is attached to the jig that supports the cantilever. Therefore, in order to detect the displacement of the cantilever by a measuring method using light such as an optical lever method, In order for the upper surface to avoid interference with the Z scanner, the jig must protrude from the Z scanner, so the present invention is effective.

  As described above, according to the present invention, even when the cantilever is driven at high speed in the Z direction, the amount of interaction due to the atomic force between the cantilever and the sample can be accurately measured by a measurement method using light such as an optical lever method. And can be suitably used for a high-speed atomic force microscope and its cantilever support.

DESCRIPTION OF SYMBOLS 100 Atomic force microscope 10 Microscope main body 11 XY scanner 12 Z scanner 13 Jig 14 Cantilever 14 'Dummy cantilever 15 Piezo driver 16 Laser light source 17 Bisection photodiode 18 Sample stage 20 Processing part 21 Amplitude measurement part 22 Subtractor 23 PID Arithmetic unit 24 Arithmetic control unit 30 Monitor 131 Mounting surface 132 Left leg 133 Right leg 134 Horizontal leg 135 Cantilever mounting unit 136 Dummy cantilever mounting unit 141 Laser light reflecting surface 43 Jig 431 Mounting surface 432 Bottom surface 433 Cavity

Claims (10)

A cantilever having a probe, and while changing the relative position of the cantilever and the sample in the sample surface direction, the amount of interaction generated by the atomic force between the cantilever and the sample is constant, By controlling the position of the cantilever in the height direction, an atomic force microscope that acquires information on the surface of the sample,
A cantilever support for supporting the cantilever;
A Z scanner that drives the cantilever support with the height direction as a driving direction;
The cantilever support has a cantilever mounting portion that protrudes in a direction perpendicular to the driving direction of the Z scanner, and a balance protrusion that protrudes in a direction opposite to the protruding direction of the cantilever mounting portion. Atomic force microscope.   The atomic force microscope according to claim 1, wherein the cantilever support has a shape and a specific gravity distribution in which moments generated by driving the Z scanner are balanced.   3. The atom according to claim 1, wherein the cantilever support has a plane-symmetric shape with respect to a second plane that includes a drive shaft of the Z scanner and is perpendicular to a protruding direction of the cantilever mounting portion. Atomic force microscope.   The said cantilever support tool has a plane symmetrical shape about the 1st plane parallel to the protrusion direction of the said cantilever attachment part including the drive shaft of the said Z scanner. An atomic force microscope according to claim 1.   The cantilever support is formed with an attachment surface attached to the Z scanner at the top, and a first leg extends obliquely downward from the attachment surface, and a second leg extends in a direction opposite to the first leg. The leg portion extends, the first leg portion and the second leg portion are connected by a horizontal leg portion at a lower end portion, and the cantilever attaching portion is connected to the connecting portion between the first leg portion and the horizontal leg portion. The balance protruding portion having the same shape as the cantilever mounting portion protrudes from a connecting portion between the second leg portion and the lateral leg portion. Item 5. The atomic force microscope according to Item 4.   5. The atomic force according to claim 1, wherein the cantilever support has a substantially trapezoidal conical shape with a mounting surface formed on a top thereof and attached to the Z scanner. microscope.   The said cantilever is attached to the said cantilever attaching part, The dummy cantilever which is not used for acquisition of the information of the surface of a sample is attached to the said balance protrusion part, The Claim 1 thru | or 6 characterized by the above-mentioned. Atomic force microscope. A cantilever support that is attached to a Z scanner of an atomic force microscope that supports a cantilever and drives the height direction of the cantilever with respect to a sample surface as a driving direction,
A cantilever support, comprising: a cantilever mounting portion that protrudes in a direction orthogonal to the driving direction of the Z scanner; and a balance protrusion that protrudes in a direction opposite to the protruding direction of the cantilever mounting portion.   With respect to a second plane that includes the central axis and is perpendicular to the protruding direction of the cantilever mounting portion, the surface is symmetrical with respect to the axis that coincides with the driving axis of the Z scanner when attached to the Z scanner. The cantilever support according to claim 8, wherein the cantilever support is provided. With respect to a first plane that includes the central axis and is parallel to the protruding direction of the cantilever mounting portion, the surface is symmetrical with respect to the axis that coincides with the driving axis of the Z scanner when attached to the Z scanner. The cantilever support according to claim 8 or 9, wherein the cantilever support is provided.