JP5632131B2 - Method of vibrating cantilever for scanning probe microscope and scanning probe microscope using the method - Google Patents

Description

  The present invention oscillates a cantilever having a probe at the tip, detects the interaction acting on the sample surface, performs distance control, relatively scans the probe and the sample, and shapes and physical characteristics of the sample surface The present invention relates to a method for exciting a cantilever for a scanning probe microscope and a scanning probe microscope using the method for measuring the above, processing a sample surface, or moving a material on the sample surface with a probe.

  Based on FIG. 7, the structure of a conventional vibration-type scanning probe microscope will be described (see Patent Document 1).

  In a conventional scanning probe microscope, a submerged cell 101 is placed on a three-axis fine movement mechanism 102, the solution is filled in the submerged cell 101, and a sample 103 is set.

  A cantilever 106 having a probe at the tip is disposed at a position facing the sample.

  In the cantilever holder for holding the cantilever 106, the piezoelectric element 110 is fixed to the base portion 104 via the insulator 109, and the holding block 108 is fixed via the insulator 109. A cantilever 106 is detachably fixed to the holding block 108 by a cantilever presser 107. The cantilever 106, a part of the holding block 108, and the cantilever presser 107 are immersed in the solution.

  Above the cantilever holder 104, an optical lever type displacement detection mechanism 114 composed of a laser and a detector is disposed. A glass plate 111 is fixed to the base portion 104 so as to be positioned above the cantilever 106. By bringing the glass plate 111 into contact with the liquid surface, the liquid surface can be prevented from shaking and the laser beam of the displacement detection mechanism 114 can enter and exit between the liquid and the air without being scattered on the liquid surface. .

  A measurement method of the scanning probe microscope using the apparatus configured as described above will be described. The displacement detection mechanism 114 measures the amplitude and phase of the cantilever 106 while the cantilever 106 is vibrated in the vicinity of the primary resonance frequency by the piezoelectric element 110 acting as an excitation mechanism, and the sample 103 is brought close to the probe of the cantilever 106. To go. Then, a physical force such as an atomic force acts between the sample 103 and the probe, and the sample 103 and the probe come into intermittent contact in response to the vibration of the cantilever 106 as they come closer to each other. The contact force acts on. Due to the interatomic force or contact force, the amplitude, phase, or resonance frequency of the cantilever 106 changes. Since the amount of change depends on the distance between the probe and the sample, the distance between the probe and the sample is set to the three-axis fine movement mechanism 102 so that the amount of change in the amplitude and phase of the cantilever or the resonance frequency is always constant. By controlling with, distance control in the height direction is performed. Furthermore, the shape image of the sample surface can be measured by raster scanning the probe 3 within the surface of the sample 101 by the triaxial fine movement mechanism 102.

  In the case of the vibration type atomic force microscope, in addition to the method of performing excitation near the first-order resonance frequency described above, there is also a method for performing measurement while exciting near the second-order or higher-order resonance frequency. is there. In the case of higher-order vibration modes, it is applied to measurements that take advantage of the characteristics of each vibration mode. For example, in the case of a vibration mode in which torsional vibration occurs around the long axis of the cantilever, there is a feature that the distance between the sample being measured and the probe can be kept substantially constant.

  When measuring with a scanning probe microscope, cantilevers with various shapes and special functions are commercially available depending on the sample type, measurement method, and physical quantity to be measured. Select the most suitable cantilever and place it in the cantilever holder. Used.

  In addition to the case where the measurement is performed in the liquid described with reference to FIG. 7, the measurement by the scanning probe microscope is performed in the air or in a vacuum. The apparatus configuration and measurement method in this case are substantially the same as in FIG. 7, but in the case of measurement in air, the submerged cell 101, the glass plate 111, etc. are not required in FIG. The sample and the cantilever are arranged in a vacuum chamber.

JP 2003-329565 A

  In the scanning probe microscope configured in this way, the excitation force by the excitation mechanism of the cantilever holder may be insufficient, and the cantilever may not obtain a sufficient amount of amplitude. At this time, the noise level with respect to the amplitude detection signal in the signal detected by the displacement detection mechanism is increased, the measurement accuracy is deteriorated, and the resolution is lowered. In addition, in order to obtain a sufficient amount of amplitude, when the amplitude of the excitation mechanism is increased by increasing the voltage applied to the piezoelectric element, the vibration of the members constituting the cantilever holder and the scanning probe microscope increases. Vibration noise increases.

  In particular, when measurement is performed in a solution, a sufficient amplitude cannot be obtained due to the viscous resistance that the cantilever receives from the solution, and the noise level of the signal of the displacement detection mechanism becomes very high. In addition, when the amplitude of the excitation mechanism is increased, vibration noise increases, and the glass plate and the liquid surface also vibrate, and the laser spot of the displacement detection mechanism vibrates finely, generating noise. As a result, the resolution of the scanning probe microscope was deteriorated.

  Accordingly, an object of the present invention is to reduce the noise level of the displacement detection mechanism by a vibration method in which the cantilever vibrates efficiently in a vibration type scanning probe microscope, and to suppress the vibration noise of the member, thereby measuring with high resolution. It is an object to provide a method for exciting a cantilever for a scanning probe microscope and a scanning probe microscope using the same.

  The present invention provides the following means in order to solve the above problems.

In the cantilever oscillating method of the present invention, a cantilever holder having a holding block for holding the base portion of the cantilever having a probe at the tip and a base portion at the end, and vibrating the holding block to move the cantilever Operation of the cantilever when performing measurement as a scanning probe microscope in a scanning probe microscope having an excitation mechanism for exciting and an optical lever type displacement detection mechanism for detecting displacement of the cantilever A first frequency adjusting step for setting the frequency to an arbitrary frequency between the resonance peak and the baseline in the resonance spectrum of the cantilever, and the structure of the cantilever holder including the holding block vibrates in a vibration mode in a resonance state. Frequency and the behavior of the cantilever when measuring with a scanning probe microscope A wave number, with a, a second frequency adjustment step of adjusting it to match.

  In the present invention, when measurement is performed in a vibration mode in which the longitudinal axis of the cantilever is bent and deformed by the operating frequency, the operation related to vibration in the resonance state of the structure of the cantilever including the holding block is performed. The cantilever performs a translation operation or a bending operation in a plane where the bending deformation is performed.

  Further, when the measurement is performed by vibrating in the torsional mode around the longitudinal axis of the cantilever at the operating frequency, the operation related to the resonance state of the structure of the cantilever holder including the holding block is the longitudinal direction of the cantilever. An operation to give a rotational moment around the direction axis was performed.

Further, in the cantilever oscillating method of the present invention, when the measurement is performed by immersing part or all of the cantilever and the holding block in a liquid, the second frequency adjustment step is performed by the scanning probe microscope. It was made to carry out in the liquid at the time of measuring .

In the cantilever excitation method of the present invention, the excitation mechanism includes a piezoelectric element, the piezoelectric element is attached to the cantilever holder, and the second frequency adjustment step includes the piezoelectric element and / or the holding. The block shape was adjusted.

Further, the present invention shows the above-mentioned as well as providing a scanning probe microscope for performing measurements by a vibration method of cantilever, the cantilever holder, removable structure comprising a pre-Symbol retaining blocks from the base portion structure provided in it It was.

  In the present invention, in the vibration method of a scanning cantilever for a scanning probe microscope of a vibration type that vibrates the cantilever on the primary or higher order resonance spectrum, the holder is structured as described above, so that the measurement by the scanning probe microscope can be performed. Since the operating frequency of the cantilever and the frequency when the structure of the cantilever holder including the holding block vibrates in the vibration mode in the resonance state are matched, it is possible to efficiently excite the piezoelectric element. Even when driven with a low voltage, the cantilever can vibrate with a large displacement, and the noise component of the signal of the displacement detection mechanism is reduced, enabling measurement with high resolution.

  Further, the vibration efficiency is further improved because the direction of displacement of the vibration mode of the cantilever and the direction of displacement of the vibration mode of the structure of the cantilever holder including the holding block are substantially matched. In this case, since the amount of deformation of the structure of the cantilever holder including the holding block in a direction other than the direction that contributes to the vibration mode during operation of the cantilever is reduced, the direction unnecessary for the members constituting the cantilever holder and the scanning probe microscope Is prevented from propagating to the vibration, and noise components caused by the vibration are reduced. In addition, even when the cantilever is vibrated with a low amplitude, the noise level of the displacement detection mechanism becomes small and is not affected by vibration, so that accurate measurement is possible.

  In addition, a sufficient amount of amplitude can be obtained even in a solution in which it is difficult to obtain the amplitude of the cantilever due to viscous resistance.

  Furthermore, by making the member including the holding block replaceable, it is possible to replace the member with a holding block that operates in an optimal vibration mode according to the type of cantilever.

It is a general-view figure of the scanning probe microscope used for the measurement in air | atmosphere which concerns on 1st embodiment of this invention. It is a general-view figure which shows the operation state of the cantilever holder and cantilever of the scanning probe microscope which concerns on 1st embodiment of this invention. It is a general-view figure which shows the operation state of the cantilever holder and cantilever of the scanning probe microscope which concerns on 2nd embodiment of this invention. It is a general-view figure which shows the operation state of the cantilever holder and cantilever of the scanning probe microscope which concerns on 3rd embodiment of this invention. It is a general-view figure which shows the operation state of the cantilever holder and cantilever of the scanning probe microscope which concerns on 4th embodiment of this invention. It is a general-view figure of the scanning probe microscope used for the measurement in the solution which concerns on 5th embodiment of this invention. It is a general-view figure of the conventional cantilever holder for scanning probe microscopes.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a schematic view of a vibration type scanning probe microscope used for measurement in the atmosphere according to the first embodiment of the present invention.

  In the scanning probe microscope 1 shown in FIG. 1, a cantilever 2 made of silicon having a probe 3 at the tip of a cantilever 4 and a base 5 at the end, and a base 5 of the cantilever 2 and holding the cantilever 2 A cantilever holder 6 used for shaking, a displacement detection mechanism 7 for detecting the displacement of the cantilever 4, a triaxial fine movement mechanism 9 for finely moving the sample 8, and a sample 8 fixed to the triaxial fine movement mechanism 9 The scanning probe microscope 1 is composed of a sample stage 10 to be placed, a coarse movement mechanism 11 on which a triaxial fine movement mechanism is mounted, and a housing 12.

  In the cantilever holder 6, the end of a holding block 14 having an inclined flat surface portion 13 for placing the cantilever base portion 5 on the tip is bonded and fixed to a flat plate-shaped piezoelectric element 15 that acts as an excitation mechanism. The surface of the element 15 opposite to the bonding surface of the holding block 14 is bonded and fixed to the substrate 16. The substrate 16 is screwed to the base portion 17 of the cantilever holder 6 so as to be detachable. A leaf spring 18 is attached to the holding block 14 in order to fix the base portion 5 of the cantilever. By inserting the base portion 5 of the cantilever between the leaf spring 18 and the flat portion 13 of the holding block, the cantilever 2 is It is installed interchangeably. The base portion 17 of the cantilever holder 6 is detachably fixed to the housing 12 of the scanning probe microscope.

  The displacement detection mechanism 7 includes a semiconductor laser 19, a photodetector 21 whose surface is divided into four parts, and a beam splitter 20, and detects the displacement of the cantilever 4 by a method generally called an optical lever method. First, the light of the semiconductor laser 19 is collected, the optical path is bent by the beam splitter 20, and the rear surface of the cantilever 4 is irradiated from directly above. Since the back surface of the cantilever 4 is inclined by 10 ° with respect to the surface orthogonal to the incident light 23, the light reflected by the back surface is reflected at an angle of 20 ° with respect to the incident light and enters the detection surface of the photodetector 21. . When the longitudinal axis of the cantilever 4 is bent, the spot moves up and down within the surface of the photodetector 21. At this time, the displacement of the cantilever 4 is detected by detecting the signal intensity difference between the detection surfaces of the divided photodetectors 21. When detecting the torsion angle around the longitudinal axis of the cantilever 4, the spot moves on the photodetector 21 in the direction orthogonal to the direction in which the deflection is detected, and the signal intensity of the detection surface divided at this time is detected. By detecting the difference, the torsion angle is detected. These members constituting the displacement detection mechanism 7 are arranged in the casing 22 of the displacement detection mechanism and are installed on the casing 12 of the scanning probe microscope.

  The triaxial fine movement mechanism 9 is constituted by a cylindrical piezoelectric element. The end of the cylindrical piezoelectric element 9 is fixed, and a sample holder 10 for mounting the sample 8 is attached to the tip. The cylindrical piezoelectric element 9 performs an expansion and contraction operation in a direction parallel to the central axis of the cylinder, and an electrode portion that acts as a vertical fine movement mechanism 24 and a sample stage by moving the sample stage at the tip centered around the fixed end in an arc. An electrode portion is provided that acts as a horizontal fine movement mechanism 25 that moves the sample in the sample plane. The triaxial fine movement mechanism 9 is attached to the coarse movement mechanism 11.

  Next, the measurement method in the first embodiment will be described with reference to FIGS. FIG. 2 is a schematic view showing the vibration mode of the cantilever 4 and the structure including the piezoelectric element 15 and the holding block 14 when the piezoelectric element 15 of the cantilever holder 6 is vibrated. The illustration of the leaf spring 18 attached to the holding block is omitted.

  In the present embodiment, the cantilever 4 is vibrated in the vicinity of the primary resonance frequency. The operating frequency at this time is an arbitrary frequency between the peak of the peak waveform of the resonance spectrum and the baseline measured with the primary resonance frequency as the peak when the frequency characteristic of the amplitude of the cantilever 4 is measured. The vibration mode of the cantilever 4 at this time is a vibration mode in which the longitudinal axis of the cantilever 4 is bent and deformed as shown in FIG. 2, and the tip of the probe 3 is vertically moved with respect to the sample 8 (FIG. 2). The direction of the arrow shown on the left side of the probe 3).

  In this state, when the sample 8 is brought close to the probe 3 to the measurement region by the coarse movement mechanism 11, the amplitude of the cantilever 4 changes due to an atomic force or an intermittent contact force. Since the amplitude change amount depends on the distance between the probe 3 and the sample 8, the probe 3 is servo-operated by the vertical fine movement mechanism 24 so that the amplitude change amount at this time becomes a preset value. And the distance between the samples 8 can be kept constant. In this state, the sample 8 is raster-scanned by the horizontal fine movement mechanism 25, and an image is obtained by multiplying the applied voltage of the vertical fine movement mechanism 24 and the applied voltage of the horizontal movement mechanism 25 applied to the triaxial fine movement mechanism 9 by the calibration value. As a result, it is possible to measure the uneven shape of the sample 8.

  When the cantilever 4 is vibrated, an AC voltage having the same frequency as the operating frequency of the cantilever 4 is applied to the piezoelectric element 15 to vibrate the holding block 14 and the cantilever 4 fixed on the holding block 14 with a leaf spring 18 is used. The base unit 5 is vibrated.

  In this embodiment, the structure of the cantilever holder 6 including the piezoelectric element 15 and the holding block 14 has a tip end portion of the holding block 14 that is perpendicular to the fixed surface of the piezoelectric element 15 as indicated by a two-dot broken line in FIG. Resonance was performed in a vibration mode in which the translation operation was performed (in the direction of the arrow on the holding block 14 in FIG. 2). The excitation frequency in this vibration mode was made to coincide with the operating frequency set on the primary resonance spectrum of the cantilever 4.

  That is, the structure made up of the piezoelectric element 15 and the holding block 14 is expanding and contracting within the plane in which the longitudinal axis of the cantilever 4 undergoes bending deformation, and the amplitude of the structure made up of the piezoelectric element 15 and the holding block 14 is expanded. When the frequency characteristic is measured, an arbitrary frequency between the peak of the peak-shaped waveform of the resonance spectrum having a peak at the resonance frequency that operates in the vibration mode of the stretching operation and the baseline is the primary resonance spectrum of the cantilever 4. Matched the above operating frequency.

  At this time, the resonance frequency and the vibration mode of the structure including the piezoelectric element 15 and the holding block 14 are the shape and material of the piezoelectric element 15 and the holding block 14, the electrode pattern and the poling direction of the piezoelectric element 15, and the fixing method of the components. It is determined by the environment around the member (in the atmosphere, liquid, or vacuum).

  In the present embodiment, the material and shape of the piezoelectric element 15 are determined, polling is performed in the thickness direction, electrodes are disposed on both surfaces facing each other in the thickness direction, and the shape and material density of the holding block 14 are determined on the piezoelectric element 15. Under the model assuming the load mass, the piezoelectric element 15 is resonated in the thickness direction, so that the structure including the holding block 14 and the piezoelectric element 15 is resonated in the vibration mode of the expansion / contraction operation.

  Thus, when the tip of the holding block 14 is resonated in the expansion / contraction mode, even if the piezoelectric element 15 is driven at a low voltage, the cantilever base 5 is translated with a large displacement in a direction in which the cantilever 4 is bent. Thus, the cantilever 4 can be vibrated efficiently. As a result, the noise component of the signal of the displacement detection mechanism 7 is reduced, and measurement with high resolution becomes possible.

  Further, since the amount of deformation of the structure composed of the piezoelectric element 15 and the holding block 14 in the direction other than the direction contributing to the vibration mode during the operation of the cantilever 4 is reduced, members constituting the cantilever holder 6 and the scanning probe microscope 1 The vibration in the unnecessary direction is prevented from propagating, and the noise component caused by the vibration is reduced. In addition, when the cantilever 4 is vibrated with a low amplitude, for example, when performing high-resolution measurement, the influence of the noise level and vibration of the displacement detection mechanism 6 is reduced, and accurate measurement is possible.

  In this embodiment, the structure including the piezoelectric element 15 and the holding block 14 is fixed to the substrate 16, and the substrate 16 can be attached to and detached from the base portion 17 of the cantilever holder 6. In a scanning probe microscope, a cantilever having a primary resonance frequency of about several kHz to 1 MHz is generally selected and used in accordance with the purpose of measurement. Also, it may be used in higher-order vibration modes other than the primary. Therefore, the shape and material of the piezoelectric element 15 and the holding block 14, the electrode pattern of the piezoelectric element 15 and the poling direction are appropriately changed according to the operating frequency and vibration mode of the cantilever 4, and the optimum resonance frequency for each cantilever to be used. By exchanging the combination of the piezoelectric element 15 having the vibration mode and the holding block 14 together with the substrate 16, it becomes possible to correspond to the vibration mode during operation for each type of cantilever.

(Second embodiment)
FIG. 3 is a schematic diagram showing the vibration mode of the structure including the piezoelectric element 15 and the holding block 14 and the cantilever 4 when measurement is performed while vibrating the cantilever 2 near the primary resonance frequency, as in the first embodiment. is there. Since the structure and measurement principle of the main body of the scanning probe microscope are the same as those in the first embodiment, detailed description thereof is omitted.

  In this embodiment, when the structure composed of the piezoelectric element 15 and the holding block 14 is resonated, the portion where the piezoelectric element 15 is bonded to the substrate 16 is held as a fixed end, as shown by a two-dot broken line in FIG. The vibration mode in which the tip of the block 14 is bent and deformed in a plane including the longitudinal axis of the cantilever 4 and the longitudinal direction of the holding block 14 (thickness direction of the piezoelectric element 15) (the arrow shown on the holding block 14 in FIG. 3) In the direction of). At this time, the frequency of the alternating voltage applied to the piezoelectric element 15 was made to coincide with the operating frequency on the primary resonance spectrum in which the longitudinal axis of the cantilever 4 performs bending vibration.

  In the present embodiment, the piezoelectric element 15 is polled in the thickness direction, electrodes are provided on two surfaces facing the thickness direction, a voltage is applied, and the piezoelectric element 15 and the holding block resonate due to bending deformation. Fourteen shapes were designed.

  Thus, when the holding block 14 is resonated in the bending mode and the tip is moved in a circular arc, a large rotational moment can be applied in the direction of bending deformation to the longitudinal axis of the cantilever 4, and the cantilever 4 can be efficiently applied. Therefore, the same effect as that of the first embodiment can be obtained.

(Third embodiment)
FIG. 4 is a schematic view showing the vibration mode of the cantilever 4 and the structure composed of the piezoelectric element 15 and the holding block 14 when the scanning probe microscope is measured while vibrating the cantilever 4 in the torsion mode. FIG. 4 is a view of the cantilever 4 mounted on the holding block 14 as viewed from the front side of the probe 3 perpendicular to the longitudinal axis in FIG. Since the structure of the main body of the scanning probe microscope is the same as that of the first embodiment, detailed description thereof is omitted.

  In the present embodiment, when the structure including the piezoelectric element 15 and the holding block 14 is in a resonance state, a portion where the piezoelectric element 15 is bonded to the substrate 16 is used as a fixed end as shown by a two-dot broken line in FIG. The tip of the holding block 14 vibrates in a vibration mode in which bending deformation is performed in a plane orthogonal to the plane including the longitudinal axis of the cantilever 4 and the tip of the probe 3 (shown on the holding block 14 in FIG. 4). Arrow direction). At this time, the frequency of the AC voltage applied to the piezoelectric element 15 was made to coincide with the operating frequency on the resonance spectrum where the cantilever 4 vibrates in the torsion mode around the longitudinal axis.

  In the present embodiment, the piezoelectric element 15 is polled in the thickness direction, electrodes are provided on two surfaces facing the thickness direction, a voltage is applied, and the piezoelectric element 15 and the holding block resonate due to bending deformation. Fourteen shapes were designed.

  Thus, when the holding block 14 is resonated in the bending mode and the tip is moved in a circular arc, a large rotational moment can be applied in a direction in which torsional vibration is applied to the cantilever 4, and the cantilever can be vibrated efficiently. Become.

  When the sample and the probe are brought close to each other while the cantilever 4 is vibrated at such a frequency as to vibrate in the torsion mode, the amount of twist changes according to the distance between the probe and the sample. The distance between the probe 3 and the sample 8 can be controlled to be constant by controlling the distance with the vertical fine movement mechanism 24 so that the twist amount is set in advance.

(Fourth embodiment)
FIG. 5 shows a schematic view of a structure including the piezoelectric element 30 and the holding block 31 of the cantilever holder of the scanning probe microscope according to the fourth embodiment of the present invention. In this embodiment as well, measurement is performed while vibrating the cantilever 4 in a vibration mode in which bending deformation is performed near the primary resonance frequency.

  In the present embodiment, the flat piezoelectric element 30 is fixed to the substrate 34, the end of the flat holding block 31 is bonded, and the flat portion 33 for holding the base portion 5 of the cantilever is provided at the tip, and the base portion 5 of the cantilever is provided. Is placed on the flat surface portion 33 and pressed by the leaf spring 32.

  In the present embodiment, as shown by a two-dot broken line in FIG. 5, the holding block 31 has a bonded portion to the piezoelectric element 30 as a fixed end, and the cantilever 4 is in a resonance operation in a plane in which the cantilever 4 is bent and deformed along the longitudinal axis. It was made to vibrate in a vibration mode in which bending deformation was sometimes performed (the direction of the arrow described on the holding block 31 in FIG. 5). The frequency applied to the piezoelectric element 30 at this time was made to coincide with the operating frequency on the primary resonance spectrum of the cantilever 4.

  Also in the case of this embodiment, a rotational moment can be given in the direction in which the cantilever 4 is bent and deformed, and the cantilever 4 can be vibrated efficiently.

(Fifth embodiment)
FIG. 6 is a schematic view of a scanning probe microscope for performing measurement in the liquid according to the fifth embodiment of the present invention. In this embodiment, the same parts as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this embodiment, a glass plate 42 provided with a projection 43 having a flat surface portion is attached to the base portion 40 of the cantilever holder 40. A piezoelectric element 15 acting as a vibration mechanism is bonded and fixed to the glass plate 42, and a holding block 14 provided with an inclined flat surface portion 13 on which the base portion 5 of the cantilever is mounted is fixed to the piezoelectric element 15. The cantilever 2 has a base portion 5 mounted on the inclined flat surface portion 13 of the holding block 14 and is exchangeably attached by a leaf spring 18.

  On the other hand, the submerged cell 44 is placed on the sample holder 10 on the triaxial fine movement mechanism 9. The sample 8 is fixed to the bottom surface of the submerged cell 44 and the solution 45 is put inside the submerged cell 44. 8 is a state immersed in the solution. As the probe 3 and the sample 8 are brought closer, the liquid level comes into contact with the flat surface of the projection 43 of the glass plate 42. At this time, the cantilever 2 and part of the tip of the holding block 14 are also immersed in the solution. The laser beam 23 from the displacement detection mechanism 7 disposed on the upper part of the cantilever holder 40 passes through the glass plate 42 and enters the solution 45, is reflected on the back surface of the cantilever 4, and again passes from the solution 45 through the glass plate 42 into the atmosphere. It reaches the arranged photodetector 21 and detects the amount of deflection and the amount of twist of the cantilever 4.

  When the holding block 14 is vibrated with the piezoelectric element 15 in a state immersed in the solution, the resonance frequency shifts to a lower frequency side than when it is vibrated in the atmosphere. The resonance frequency of the cantilever is also shifted to the low frequency side. In the present embodiment, as in the case shown in FIGS. 2 to 4, when the structure including the holding block 14 and the piezoelectric element 15 performs a resonance operation, the cantilever is vibrated in the vibration mode of the expansion / contraction operation or the bending operation. 4 is operated by bending the longitudinal axis or in a resonance mode of torsional motion around the axis. At this time, the shape of the structure including the holding block 14 and the piezoelectric element 15 was changed so as to be in a resonance state at the same frequency as the operating frequency of the cantilever in the solution.

  Further, the glass plate 42 can be detached from the base portion 41 of the cantilever holder 40, and the optimum combination of the holding block 14 and the piezoelectric element 15 can be selected in accordance with the type of the cantilever 2.

  With this configuration, the cantilever 4 can be efficiently vibrated even in the solution.

  Although the embodiment of the present invention has been described above, the present invention is not limited to this.

  The vibration mode of the cantilever is not limited to the above-described primary bending vibration or torsional vibration, and any resonance mode can be applied.

  In addition, the normal cantilever is vibrated in the vicinity of the resonance frequency. Even when the cantilever is vibrated in a non-resonant state, the cantilever holder includes a holding block that vibrates in the vibration mode of the cantilever and the resonance mode. If the frequency of the structure matches, it is included in the present invention.

  In the above embodiment, the distance control is performed using the amplitude change amount as a parameter. However, the distance control is performed based on the AC signal for excitation and the phase difference between the cantilever vibration detected by the displacement detection mechanism and the change in the resonance frequency. May be performed.

  The measurement environment is not limited to the atmosphere or the solution, and can be applied in a vacuum.

  In the above embodiment, the triaxial fine movement mechanism is attached to the sample side, but it may be attached to the cantilever side, or may be divided and attached to the sample and the cantilever side.

  Further, the displacement detection mechanism is not limited to the optical lever system, and for example, a system in which a resistor is provided on a cantilever and a resistance value is detected may be used.

  If the structure including the holding block vibrates in the vibration mode in the resonance state, any actuator other than the piezoelectric element can be used as the actuator used in the vibration mechanism. For example, magnetic force, electromagnetic force, light, heat, etc. can be used as energy. An excitation mechanism as a source can also be used.

  The holding mechanism and the vibration mechanism such as the piezoelectric element do not necessarily have to be directly bonded, and they may be attached separately. In addition, an excitation mechanism may be provided outside the cantilever holder to vibrate the holding block.

  Further, the present invention is not limited to an atomic force microscope that measures unevenness of a sample, but is applied to a scanning probe microscope that uses various vibration methods for measuring electrical characteristics, magnetic characteristics, optical characteristics, mechanical characteristics, and the like. be able to.

DESCRIPTION OF SYMBOLS 1 Scanning probe microscope 2 Cantilever 3 Probe 4 Cantilever 5 Cantilever base 6 and 40 Cantilever holder 7 Displacement detection mechanism 8 Sample 9 Triaxial fine movement mechanism 10 Sample holder 11 Coarse movement mechanism 12 Case
14, 31 Holding block 15, 30 Piezoelectric element (vibration mechanism)
16, 34 Substrate 17, 41 Base part 18, 32 of cantilever holder Leaf spring 19 Semiconductor laser 20 Beam splitter 21 Photo detector 24 Vertical fine adjustment mechanism 25 Horizontal fine adjustment mechanism 42 Glass plate 44 Submerged cell

Claims (7)

A cantilever holder having a holding block for holding the base portion of the cantilever having a probe at the tip and a base portion at the end, and a vibration mechanism for vibrating the holding block to vibrate the cantilever; In a scanning probe microscope equipped with an optical lever type displacement detection mechanism for detecting the displacement of the cantilever,
A first frequency adjustment step of setting the operating frequency of the cantilever when performing measurement as a scanning probe microscope to an arbitrary frequency between the resonance peak and the baseline in the resonance spectrum of the cantilever;
A second frequency adjusting the frequency at which the structure of the cantilever holder including the holding block vibrates in a vibration mode in a resonance state and the operating frequency of the cantilever at the time of measurement with a scanning probe microscope are matched. And a frequency adjusting step. A method of exciting a cantilever for a scanning probe microscope.   When measurement is performed in a vibration mode in which the longitudinal axis of the cantilever is bent and deformed by the operating frequency, the operation related to vibration in the resonance state of the structure of the cantilever including the holding block is bent and deformed. The method for exciting a cantilever for a scanning probe microscope according to claim 1, wherein the method is a translation operation or a bending operation within a plane in which the scanning probe microscope is performed.   When measurement is performed by vibrating in the torsional mode around the longitudinal axis of the cantilever at the operating frequency, the operation related to the vibration in the resonance state of the structure of the cantilever holder including the holding block is the longitudinal direction of the cantilever. 2. The method for exciting a cantilever for a scanning probe microscope according to claim 1, wherein the rotating moment is applied around a direction axis.   When the measurement is performed by immersing a part or all of the cantilever and the holding block in the liquid, the second frequency adjustment step is performed in the liquid when performing the measurement with the scanning probe microscope. The method for exciting a cantilever for a scanning probe microscope according to any one of claims 1 to 3. The method for exciting a cantilever for a scanning probe microscope according to any one of claims 1 to 4,
A scanning probe in which the excitation mechanism includes a piezoelectric element, the piezoelectric element is attached to the cantilever holder, and the second frequency adjustment step is performed by adjusting the shape of the piezoelectric element and / or the holding block. A method for exciting a cantilever for a microscope.   A cantilever having a probe at the tip and a base at the end, a cantilever holder structure having a holding block for holding the base, and a cantilever holder base that fixes the cantilever holder structure to the main body A vibrating mechanism for vibrating the holding block to vibrate the cantilever, and an optical lever type displacement detecting mechanism for detecting the displacement of the cantilever,
  The scanning probe microscope characterized in that the cantilever holder structure has a resonance frequency equal to the operating frequency of the cantilever when the scanning probe microscope is measured. The scanning probe microscope according to claim 6,
A scanning probe microscope in which the cantilever holder structure is detachable from the cantilever holder base.