JP2008209127A - Scanning probe microscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scanning probe microscope capable of correcting the optical axis shift of a displacement detection mechanism caused by the difference of a cantilever or a solution or the warpage of the cantilever in the atmosphere or the solution. <P>SOLUTION: In the scanning probe microscope for measurement in a liquid composed of a displacement detection mechanism 10 constituted of a light source part 11 and a light detection part 13 and a cantilever holder 30 having a liquid level holding part 31 comprising a material pervious to the light of the light source part 11, the cantilever holder 30 is constituted so that the thickness of an incident light passing part in the direction vertical to the incident surface 31b of the incident light of the liquid level holding part 31 and the thickness of the reflected light passing part in a direction vertical to a reflected light emitting surface 31c. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention detects the interaction between a cantilever having a probe at the tip and the sample surface in the atmosphere or in a liquid and controls the distance between the sample and the probe by a fine movement mechanism while performing distance control. The present invention relates to a scanning probe microscope for measuring surface irregularities and physical characteristics, processing a sample surface, or moving a material on a sample surface with a probe.

  In a conventional scanning probe microscope, a base portion provided at the end of a cantilever having a probe at the tip is fixed to a cantilever holder, and a sample is placed on a three-axis (XYZ axis) fine movement mechanism constituted by a cylindrical piezoelectric element or the like. It is a mounted configuration.

  When measuring with a scanning probe microscope, the sample is brought close to the probe by a coarse movement mechanism such as a stepping motor, and then the probe and the sample are sufficiently brought close to each other by a triaxial fine movement mechanism. Then, a physical force such as an interatomic force acts between the sample and the probe, and the probe receives an attractive force at the beginning, and the probe receives a repulsive force as it approaches further. These attractive and repulsive forces cause the cantilever to bend. The deflection at this time is usually detected by a displacement detection mechanism called an optical lever system.

  In the optical lever method, laser light (incident light) is irradiated on the back surface of the cantilever from a light source such as a semiconductor laser. This incident light is reflected by the back surface of the cantilever, and the reflected light strikes a photodetector comprising a cantilever semiconductor detector. In this photodetector, the light receiving surface is divided into two parts up and down, or four parts up and down and left and right, and the incident position of the reflected light can be detected from the light amount of the divided light receiving surface to measure the deflection amount of the cantilever. It is.

  The physical force such as the interatomic force depends on the distance between the probe and the sample, and the probe and the sample are brought close to the region in which the interatomic force acts, and the three-axis fine movement mechanism is used in a two-dimensional plane. By controlling the distance between the sample and the probe so that the amount of deflection of the cantilever is always constant while scanning with, an uneven image on the sample surface is imaged. Such a distance control method is called a contact-type atomic force microscope. At this time, it is also possible to measure physical properties such as electrical physical properties and optical physical properties by detecting physical actions at the probe tip and the sample surface.

  In addition to the contact-type atomic force microscope described above, a vibration-type atomic force microscope is also widely used. In this method, a vibrating means such as a piezoelectric element is provided in the cantilever holder, the cantilever is vibrated at a frequency near the resonance frequency by the vibrating means, and the amplitude and phase at that time are measured by a displacement detecting means such as an optical lever method. . When the probe and the sample are sufficiently close together, a physical force such as an interatomic force acts between the sample and the probe, and when closer, the sample and the probe respond to the vibration of the cantilever. Contact intermittently, and contact force acts on both. The atomic force and contact force change the amplitude and phase of the cantilever. Since these forces depend on the distance between the probe and the sample, distance control is performed by controlling the distance between the sample and the probe so that the amount of change in the amplitude and phase of the cantilever is always constant. . The vibration-type atomic force microscope has an advantage that it causes less damage to the probe and the sample than the contact-type atomic force microscope.

  Many scanning probe microscope measurements are performed in the atmosphere. For example, in the case of organic or biological samples such as macromolecules, cells, chromosomes, DNA, and proteins, the samples may be altered by exposure to the atmosphere. Therefore, the sample and the cantilever may be immersed in a solution such as a culture solution for measurement. For example, in-situ observation of biological samples or organic polymer samples, or measurements that combine electrochemical reactions in the solution. Applied.

  Here, the principle will be described with reference to an overview of the conventional scanning probe microscope for measurement in liquid in FIG. 7 (see, for example, Patent Document 1).

  This prior art is a contact-type atomic force microscope that observes the sample S with a cantilever 101 having a probe at the tip. The cantilever support portion 102 that supports the cantilever 101 and the cantilever 101 are displaced by an optical lever method. A displacement detection mechanism (103, 104, 105, 106) for measurement, a solution cell 111 for holding the sample S in the solution 110, and a triaxial fine movement mechanism 107 for scanning the sample S by moving the sample S relative to the cantilever 101 are provided. Prepare.

  The solution cell 111 includes a bottom surface 118 that supports the sample S and a side wall 119 that surrounds the periphery of the bottom surface 118, and can hold the solution 110 inside. The solution 110 is injected into the solution cell 111, and the cantilever 101 and the sample S are immersed in the liquid.

The displacement detection mechanism includes a laser light source 103 that emits laser light, a beam splitter 104 that directs the emitted laser light toward the cantilever 101, a mirror 105 that adjusts the direction of the laser light reflected by the cantilever 101, and a reflected laser. A photodiode 106 for detecting light is provided.
Here, the cantilever support portion 102 is made of a permeable material, and is disposed in a state where the side on which the cantilever is supported is immersed in the solution. The incident laser beam and the reflected laser beam with respect to the cantilever 101 are transmitted from the atmosphere through the cantilever support portion 102 made of a transmissive material, pass through the solution 110, and are reflected by the cantilever 101 disposed in the solution. The light enters the cantilever support 102 from 110 again, and passes through the atmosphere to the photodiode 106 via the mirror 105. If laser light is incident on the solution as it is from the atmosphere, the accuracy of displacement detection is greatly reduced due to irregular reflection due to shaking of the surface of the solution and changes in the optical path. However, in this prior art, the interface between the cantilever support portion 102 and the solution is continuously connected, and the cantilever support portion 102 also serves as a liquid level holding portion. The incident light of the laser can travel directly into the solution, and the displacement of the cantilever 101 can be accurately measured even in the solution.
In this state, by using the three-axis fine movement mechanism, the sample is scanned in the sample plane while feedback controlling the distance between the cantilever 101 and the sample S so that the displacement of the cantilever 101 is constant. A shape image can be measured.
JP-A-11-142418

  However, in the conventional cantilever holder in a scanning probe microscope for measurement in liquid, the laser beam travels in a cantilever support made of a transparent material or in a solution. Defocus occurs when traveling in the atmosphere. In addition, since the light is refracted when traveling in the atmosphere, the incident position on the photodiode is shifted.

  In a general scanning probe microscope, the cantilever has a width of several tens of μm, and an optical system that forms an image of light from the light source on the back surface of the cantilever using a lens is used to irradiate light to a narrow region.

  In addition to measuring in solution, it is often possible to use both atmospheric measurement and measurement in solution to improve versatility. To reduce costs, the displacement detector mechanism is used for atmospheric and solution applications. In most cases, it is also used in

  For defocusing, the thickness of the liquid level holder attached to the cantilever holder (corresponding to the conventional cantilever holder) is adjusted, and the holder is designed to focus on the back of the cantilever even in solution. When incident light and reflected light are passed through a liquid surface holding portion having the same thickness, the incident position on the photodiode is greatly shifted due to refraction.

  For this reason, it has been necessary to increase the mirror of the displacement detection mechanism to provide an adjustment mechanism, or to incorporate a positioning mechanism having a moving amount larger than that required in the atmosphere in the photodiode. In this case, due to the increase in size of the apparatus and the increase in operating parts, the rigidity is lowered and the measurement accuracy is deteriorated. Furthermore, the problem that the number of parts increased and the cost increased occurred.

  In addition, scanning probe microscopes select cantilevers of various shapes according to the purpose of measurement, and furthermore, since solutions with various refractive indexes are used, the reflected light incident on the photodiode may be displaced in some cases. In some cases, the adjustment range of the detection mechanism was exceeded and measurement was not possible.

In addition, the conventional cantilever for a scanning probe microscope is warped due to temperature or internal stress of the metal coating provided on the cantilever, and the reflected light to the photodetector shifts when detecting displacement by the optical lever method. There was a case.
An object of the present invention is to provide a scanning probe microscope capable of correcting an optical axis shift of a displacement detection mechanism due to a difference in cantilever or solution, warpage of the cantilever, etc., regardless of whether it is in the air or in a solution. is there.

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

  The scanning probe microscope for measuring in liquid according to the present invention includes a cantilever having a probe at the tip and a base at the end, and a sample for placing a sample to be measured disposed at a position facing the probe. Displacement detection mechanism that consists of a holder part, a light source part, and a light detection part, irradiates the back surface of the cantilever with light from the light source part, and receives the reflected light from the cantilever with the light detection part to detect displacement of the cantilever Part, a cantilever fixing part for fixing the base part of the cantilever, and a cantilever holder which is disposed above the cantilever and has a liquid level holding part made of a material transmissive to the light of the light source part. The

  The sample and the cantilever are disposed in an arbitrary solution, the displacement detection mechanism is disposed in the atmosphere, the surface above the cantilever of the liquid level holding unit is in contact with the solution, and incident light from the light source to the cantilever is In the atmosphere, the liquid level holding part, the reflected light after passing in the order of the solution and reflected by the cantilever reaches the light detection part through the liquid, the liquid level holding part, the optical path in the order of the atmosphere, Cantilever displacement detection is performed.

  In the scanning probe microscope for in-liquid measurement configured as described above, according to the present invention, the thickness of the incident light passing part perpendicular to the incident light incident surface of the liquid level holding part and the emission of the reflected light The thickness of the reflected light passing portion in the direction perpendicular to the surface is different.

  Further, in the scanning probe microscope for measuring in liquid according to the present invention, the reflected light in the liquid level holding part is more than the thickness of the incident light passing part perpendicular to the incident light incident surface of the liquid level holding part. The thickness of the reflected light passing portion in the direction perpendicular to the emission surface of the light is increased.

  Furthermore, in the scanning probe microscope of the present invention, in the liquid level holding part, at least a portion of the surface in contact with the solution through which the incident light and the reflected light pass is disposed on the same plane, and the incident light and the reflection on the surface in contact with the atmosphere are reflected. The surface through which light passes was not on the same plane.

  In the scanning probe microscope for measuring in liquid according to the present invention, a substrate that is transmissive to the light from the light source unit is inserted into the optical path on the reflected light side in the atmosphere.

  Furthermore, in the scanning probe microscope of the present invention, a common displacement detection mechanism is used so that measurement in the atmosphere and measurement in the solution can be combined.

  Further, in the scanning probe microscope of the present invention, a cantilever having a probe at the tip and a base at the end, a sample holder part placed at a position facing the probe, and for placing a sample to be measured, A displacement detection mechanism that is composed of a light source unit and a light detection unit, irradiates the back surface of the cantilever with light from the light source unit, receives light reflected from the cantilever by the light detection unit, and detects displacement of the cantilever; The cantilever holder has a cantilever fixing portion for fixing the base portion of the cantilever, and a substrate transparent to the light from the light source portion is inserted into the optical path on the reflected light side.

  The present invention has the following effects.

  According to the scanning probe microscope according to the present invention, the thickness of the reflected light passage part is adjusted even when the optical path of the displacement detection mechanism is refracted in the liquid level holding part or the solution and the incident position on the light detection part is shifted. This makes it possible to arbitrarily adjust the incident position on the light detection unit.

  Therefore, it is not necessary to make the light source part of the displacement detection mechanism and the positioning mechanism of the light detection part larger than necessary, or to provide a tilt mirror for adjusting the incident position to the light detection part. It became possible to prevent deterioration. In addition, the number of parts can be reduced and the cost can be suppressed.

  Furthermore, even when the type of cantilever or solution is changed in accordance with the measurement purpose, it is possible to prevent the reflected light incident on the light detection unit from being out of the adjustment range of the displacement detection mechanism and becoming impossible to measure.

  Furthermore, the atmospheric displacement detection mechanism can be used in the solution as it is.

  Furthermore, in the scanning probe microscope of the present invention, a substrate that is transparent to the light of the light source unit is inserted in the optical path on the reflected light side, so that the ambient temperature and the coating material to the cantilever are Even when the cantilever is warped due to the internal stress, the optical axis deviation can be corrected by adjusting the thickness of the substrate.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  A first embodiment according to the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic view of a scanning probe microscope used in the atmosphere according to the first embodiment of the present invention.

  The cantilever 1 used in the present invention has a rectangular shape made of silicon, and has a structure having a triangular pyramid-shaped probe 2 at the tip and a base 3 at the end. The cantilever holder 4 is attached to a plate-type piezoelectric element 7 for cantilever excitation via a ceramic insulating substrate 6 on a base block 5 made of stainless steel, and the piezoelectric element 7 holds the cantilever 1. The cantilever holding portion 8 is bonded and fixed. When measurement is performed using the vibration method, a voltage is applied to the piezoelectric element 7 and the cantilever 1 is vibrated at a frequency near the resonance frequency of the cantilever via a cantilever holding portion 8 attached to the piezoelectric element 7. When the measurement is performed by the contact method, no voltage is applied to the piezoelectric element 7 and the electrodes of the piezoelectric element 7 are used in a short-circuited state. The base block 5 of the cantilever holder 4 thus configured is fixed to the main body base portion 9 of the scanning probe microscope.

  The displacement detection mechanism 10 used for detecting the displacement of the cantilever 1 detects the displacement of the cantilever 1 by a detection method generally called an optical lever method. The displacement detection mechanism of the present invention includes a light source unit 11, a beam splitter 12 that bends an optical path, and a light detection unit 13. These members are arranged in a case 14, and the case 14 is a main body of a scanning probe microscope. It is fixed to the base part 9.

  The light source unit 11 includes a light source composed of a semiconductor laser having a wavelength of 670 nm and a condensing lens for collecting the light of the semiconductor laser and condensing it on the back surface of the cantilever (the semiconductor laser and the condensing lens are not shown). . The photodetection unit 13 is a silicon photodiode whose surface is divided into four. The light emitted from the light source unit 11 is bent by the beam splitter 12 and condensed on the back surface of the cantilever 1 from directly above. The light reflected by the cantilever 1 is guided to the light detection unit 13.

  Here, when the deflection of the cantilever 1 occurs, the spot on the photodiode 13 moves, and the displacement of the cantilever 1 is detected by detecting the intensity difference between the four light receiving surfaces.

  Here, the light source unit 11 is provided with a biaxial stage 15 movable in the vertical direction and the vertical direction with respect to the paper surface of FIG. 1, and the cantilever 1 is shown by the optical microscope image 17 arranged on the upper side of the beam splitter 12. The laser beam is positioned on the back surface of the cantilever 1 by the biaxial stage 15 while confirming the image of the laser beam and the image of the laser spot reflected from the surface of the sample 18.

  In addition, the light detection unit 13 is also provided with a biaxial stage 16 that can move in a direction perpendicular to the left-right direction with respect to the paper surface of FIG. 1, and at the center of the photodiode 13 while checking the output of the photodiode 13. The spot of the reflected light is positioned.

  On the other hand, a sample 18 is placed on a sample stage 19 on the side facing the probe 2, and the sample stage 19 is fixed to a three-axis fine movement mechanism 20 composed of a cylindrical piezoelectric element. The triaxial fine movement mechanism 20 is fixed to a coarse movement mechanism 21 for bringing the probe 2 and the sample 18 closer by a feed screw and a stepping motor.

  In the present embodiment, vibration-type atomic force microscope measurement is performed, and the probe 2 and the sample 18 are brought close to each other by the coarse movement mechanism 21 until the preset amplitude is attenuated, and the sample 18 is obtained by the triaxial fine movement mechanism 20. By controlling the distance between the probe 2 and the sample 18 so that the amount of attenuation of the amplitude becomes constant while performing the raster scan in the plane, it is possible to measure an uneven image on the surface of the sample 18. .

  Next, FIG. 2 shows an overview of a scanning probe microscope when measuring in a liquid.

  Here, the difference between the configuration in the atmosphere in FIG. 1 and the configuration in the solution in FIG. 2 is only the cantilever holder 30 and the solution cell 35 for immersing the sample in the solution. The three-axis fine movement mechanism 20, the coarse movement mechanism 21, and the main body base portion 9 have the same configuration as that in the atmosphere of FIG. Therefore, the same number is attached | subjected to the overlapping member and detailed description is abbreviate | omitted.

  A cantilever holder 30 for measuring in liquid is attached to a liquid level holding part 31 made of quartz glass, a plate type piezoelectric element 32 for cantilever vibration attached to the liquid level holding part 31, and the piezoelectric element 32. The cantilever holding portion 33 and the liquid level holding portion 31 are fixed, and the base block 34 is made of a stainless material for fixing the cantilever holder 30 to the base portion 9 of the scanning probe microscope. The piezoelectric element 32 is waterproofed for use in a solution.

  The liquid level holding unit 31 includes a surface 31a on which the cantilever is attached and an incident surface 31b on which light from the displacement detection mechanism is incident.

  The sample is placed in the solution cell 35, and the solution cell 35 is placed on the sample holder 19. A solution (distilled water) 36 is placed in the solution cell 35, and the solution 36 is in contact with the surface 31 a of the liquid surface holding unit 31 on the side where the cantilever 1 is installed by surface tension. The cantilever 1 and the sample 18 are arranged in the solution 36.

  Here, the incident light 37 emitted from the light source unit 11 of the displacement detection mechanism 10 enters the incident surface 31 b of the liquid level holding unit 31 at an incident angle of 0 °. Since quartz glass, which is a constituent material of the liquid level holding part 31, has a transmittance of about 94% with respect to the wavelength of 670 nm of the laser light, the incident light 37 passes through the liquid level holding part 31 and further passes through the solution 36. The light passes through and is irradiated on the back surface of the cantilever 1. The cantilever 1 is mounted at a mounting angle of 13 ° with respect to the horizontal plane and reflects at a reflection angle of 26 °. The reflected light 38 passes through the solution 36, passes through the quartz glass of the liquid level holding unit 31, exits into the atmosphere, and reaches the light detection unit 13.

  Here, the optical path of the incident light 37 incident on the cantilever 1 from the light source unit 11 will be described with reference to FIG. In FIG. 3, the beam splitter 12 is omitted, and the light source unit 11 to the cantilever 1 are illustrated in a straight line.

  The light from the light source unit 11 is condensed on the back surface of the cantilever with an opening angle of 4.3 ° in the atmosphere. As shown in FIG. 1, when passing through the atmosphere, an image is formed on the back surface of the cantilever 1 at a distance of f <b> 1 from the light source unit 11. In this embodiment, f1 is 53 mm. Here, when quartz glass (refractive index 1.46) and distilled water (refractive index 1.33), which are larger than the refractive index 1 of the atmosphere, enter the optical path, the distance from the light source unit 11 to the imaging point. Extends to f2. In this example, the thickness T1 of the quartz glass portion was 24 mm, and f2 was 61 mm. At this time, the distance from the surface 31a in contact with the liquid surface of the liquid surface holding portion 31 to the cantilever 1 is about 2 mm. This distance and the area of the surface 31a in contact with the liquid surface of the liquid surface holding part 31 contribute to the amount of solution necessary for the measurement, and the measurement with a smaller amount of solution becomes possible as the distance is shorter and the area is smaller.

  Here, although the height of the mounting portion of the cantilever with respect to the main body base portion 9 of the scanning probe microscope differs in the atmosphere and in the solution, both the cantilever holders 4 can be adjusted because the height of the sample 18 can be adjusted by the coarse movement mechanism 21. , 30 can be installed without problems.

Next, the optical path of the reflected light after the cantilever reflection will be described with reference to FIGS. After being reflected at a reflection angle of 26 ° with respect to the incident light 22 from the light source unit 11 in the atmosphere, the reflected light 23 travels straight in the atmosphere and reaches the light receiving surface of the light detection unit 13.
On the other hand, in the case of measurement in liquid, since each medium has a different refractive index, the reflected light is refracted at the interface. The cantilever reflects the incident light at a reflection angle of 26 °, and the reflected light 38a traveling through the solution is refracted at a refraction angle of 23.5 ° at the interface 31a of the liquid level holding part 31 made of the solution 36 and quartz glass. Thereafter, the reflected light 38b that has traveled through the liquid level holding unit 31 is refracted at a refraction angle of 35.7 ° at the interface 31c between the liquid level holding unit 31 and the air, and then the reflected light 38c travels in the atmosphere and travels in the direction of the light detection unit. To reach. At this time, in the conventional submerged holder, the surface on which the incident light is incident on the liquid surface holding portion 31, the surface on which the reflected light 38b is emitted, and the surface on which the reflected light 38b is emitted are on the same plane and perpendicular to the incident surface 31b of the incident light 37. The thickness of the part passing through the liquid level holding part 31 in the direction is equal to the thickness of the part passing through the liquid level holding part 31 in the direction perpendicular to the emission surface of the reflected light 38b, and the reflected light 38b is incident on the incident surface 31b. The light is refracted and passes through an optical path such as 38d, and the irradiation position on the light detection unit 13 is greatly deviated from the position of the reflected light in the atmosphere shown in FIG. 1, and from the detection area of the photodiode 13 of the light detection unit. It will come off. The light detection unit 13 is provided with a biaxial stage 16 and is configured to be able to correct this deviation amount to some extent. It is necessary to mount a large two-axis stage 16, and there is a problem that there is no arrangement space and it is difficult to arrange, and even if it can be arranged, the rigidity of the apparatus decreases and the cost increases.

  In the case of the present embodiment, when the reflected light 38b is emitted on the same surface as the incident surface 31b of the incident light 38, the position of the photodiode 13 is shifted as compared with the case in the atmosphere. In addition to this, there may be a further deviation due to an error in the mounting position of the cantilever 1 or a warp that occurs during manufacturing of the cantilever.

  Therefore, in this embodiment, the quartz glass 41 having a thickness of 10 mm is attached only to the portion where the reflected light of the in-liquid cantilever holder passes, and the thickness of the quartz glass of the liquid surface holding portion 31 of the reflected light passage portion is set to the incident light passage portion. The liquid surface holding portion 31 is configured so that the incident surface 31b for incident light and the exit surface 31c for reflected light 38b are not flush with each other. As a result, the reflected light 38b that passed through the liquid level holding part 31 was refracted at the refraction angle 35.7 ° at the exit surface 31c, and passed through the optical path indicated by 38c. As a result, the amount of deviation in the light detection unit 13 is smaller than that in the case where the thicknesses of both are equal, and the amount of deviation can be suppressed to 4.5 mm compared to the case in the atmosphere. Since the biaxial stage 16 of the light detection unit is provided with a stage whose movement amount is ± 5 mm for each axis, this deviation amount can be corrected by the biaxial stage 16.

  In addition, this time, the liquid level holding part 31 is composed of three parts 39, 40, 41, a disc-shaped intermediate part 40, a liquid level holding projection part 39 and a 10 mm thick quartz glass part 41 for correction. Each was manufactured by fusing. The quartz glass portion 41 for correction may be optically brought into close contact with the matching oil having the same refractive index.

  As a result, it was possible to construct a scanning probe microscope that can be used for both atmospheric and liquid measurement by replacing only the cantilever holder and the solution cell without reducing the rigidity of the apparatus or increasing the cost.

4A is a schematic view of a scanning probe microscope for measuring in liquid used in the liquid according to the second embodiment of the present invention, and FIG. 4B is a plan view of the cantilever holder portion of FIG. 4A. It is.
In this embodiment, except for the cantilever holder 50 for measuring in liquid, the apparatus has the same configuration as that of the first embodiment. The displacement detection mechanism 10, the main body base 9 of the scanning probe microscope, the triaxial fine movement mechanism 20, and the solution cell 35 are used. Is the same as in Example 1. When used in the atmosphere, it is used in the same configuration as in FIG. Therefore, the same reference numerals are given to the overlapping members, and the detailed description is omitted, and only different portions of the configuration of the cantilever holder 50 for measuring in liquid will be described.

  The liquid level holding part 51 of the in-liquid measuring cantilever holder 50 of this embodiment is made of quartz glass, and is composed of a cylindrical base part 52 and a protruding part 53 in contact with the liquid surface fused to the tip thereof. The Further, the cylindrical base portion 52 is formed by cutting the surface on the side on which incident light is incident and opening a hole 53 to form the liquid level holding portion 51. The incident surface 51a of the incident light 55 is polished to such an extent that the scattered light of the incident light 55 does not affect the measurement.

  Incident light 55 enters the processed hole 53 and passes through the liquid level holding part 51. The thickness from the incident surface 51a of the liquid level holding part 51 to the surface 51b in contact with the solution is such that the incident light 55 travels through the quartz glass constituting the liquid level holding part 51 and the solution (distilled water) 36. The optical path length is the same as that of the optical path diagram of FIG. On the other hand, the reflected light 56 reflected by the cantilever 1 passes through a portion 54 having no hole corresponding to the cylindrical portion. At this time, the incident surface 51a of the incident light 55, the interface 51b with the solution, and the exit surface 51c of the reflected light 56b that has traveled through the liquid level holding unit 51 are processed in parallel.

  The liquid level holding part manufactured in this way is fixed to the base block 57 to constitute the cantilever holder 50 for measuring in liquid, so that the surface 51a on which the incident light 55 enters the liquid level holding part 51 and the liquid level holding. The surface 51c from which the reflected light 56b traveling through the portion 51 exits is not coplanar, and is perpendicular to the exit surface of the reflected light 56b rather than the thickness of the portion of the incident light 55 that passes through the quartz glass in the direction perpendicular to the incident surface 51a. It is possible to increase the thickness of the portion that passes through the quartz glass in any direction. With this configuration, the reflected light 56 from the cantilever 1 is refracted at the interface 51b between the solution and the quartz glass and the interface 51c between the quartz glass and the atmosphere, and passes through an optical path 56c indicated by a one-dot chain line in FIG. The light detection unit 13 is reached. As a result, similarly to the first embodiment, from the optical path 56d shown by a two-dot chain line in FIG. 4A, which is an optical path when the exit surface of the reflected light 56 is provided on the same plane as the incident surface 51a of the incident light 55. In addition, the amount of shift to the light detection unit 13 can be suppressed small.

FIG. 5 is a schematic view of a scanning probe microscope for measuring in liquid according to the third embodiment of the present invention.
In the present embodiment, except for the in-liquid cantilever holder 60 and the parallel flat substrate 70 disposed in the optical path of the reflected light, the apparatus has the same configuration as that of the first embodiment, and is the main body base of the displacement detection mechanism 10 and the scanning probe microscope. The unit 9, the triaxial fine movement mechanism 20, and the solution cell 35 are the same as those in the first embodiment. When used in the atmosphere, it is used in the same configuration as in FIG. Therefore, the same reference numerals are given to the overlapping members, and a detailed description thereof is omitted, and only different portions of the configuration of the submerged cantilever holder 60 and the parallel plane substrate 70 will be described.

  The submerged cantilever holder 60 used in the present embodiment is manufactured by fusing a projection 63 to a disk-shaped member 62 with a liquid surface holding portion 61 made of quartz glass. The incident surface 61a of the incident light 64 and the exit surface 61a of the reflected light 65b that has traveled through the liquid level holding unit 61 are formed to be on the same plane, and the incident surface 61a of the incident light 64 and the surface 61b in contact with the solution are parallel to each other. It has become. Further, the incident light 64 is arranged to enter the incident surface 61a at an incident angle of 0 °. The optical path diagram of the incident light 64 has the same dimensions as those in FIG.

  On the other hand, a parallel plane substrate 70 made of BK7 for optical path correction is inserted into the optical path of the reflected light 65 in a form separated from the cantilever holder 60. The parallel flat substrate 70 is fixed to the displacement detection mechanism 10 in a removable manner, and is disposed in parallel with the incident surface 61 a of the incident light 64 of the liquid level holding unit 61.

  The reflected light 65a reflected from the cantilever 1 at a reflection angle of 26 ° travels in the solution, enters the liquid surface holding portion 61 at a refraction angle of 23.5 °, and the reflected light 65b travels through the quartz glass, and has a refraction angle of 35. Once in the atmosphere at 7 °, the reflected light 65c travels through the air. Thereafter, the light again passes through the parallel flat substrate 70 made of BK7, and further enters the atmosphere to reach the light detection unit 13.

  Here, BK7 is a refractive index of quartz glass having a transmittance of about 92% with respect to 670 nm, which is the wavelength of the light source 11 of the displacement detection mechanism 10, and having a refractive index of 1.51 and used for the liquid surface holding unit 61. Refractive index greater than 1.46.

  Accordingly, the reflected light 65c traveling in the air is incident on the parallel plane substrate 70 at a refraction angle of 22.7 °, and the reflected light 65d (the one-dot chain line in the figure) travels in the BK 7 and again at a refraction angle of 35.7 °. It goes out to the atmosphere and reaches the light detector 13. If the parallel plane substrate 70 is not inserted, the reflected light 65b follows the optical path of the two-dot chain line 65f in FIG. 5 at a refraction angle of 35.7 ° after exiting the interface 61a with the air of the liquid level holding unit 61. The amount of deviation at the position of the light detection unit 13 becomes large.

  In this embodiment, the amount of deviation by about 3 mm can be reduced by inserting the parallel plane substrate 70. Further, the amount of correction can be made larger than that of quartz glass by using BK7 having a refractive index larger than that of quartz glass for the parallel flat substrate 70.

FIG. 6 is a schematic view of a scanning probe microscope for measuring in the atmosphere according to the fourth embodiment of the present invention.
This embodiment has the same configuration as that of the embodiment of FIG. 1 except that parallel plane substrates 80 and 81 are inserted in the optical path of the reflected light. Description is omitted.

  In this embodiment, the cantilever 1 to be used is an apparatus for performing optical path correction when warpage occurs due to the influence of the ambient temperature or the internal stress of the metal to be coated.

  First, when the cantilever 1 has a mounting angle of 13 ° and no warp occurs, a parallel flat substrate 80 made of BK7 having a thickness of 3 mm is removably inserted into the optical path of the reflected light 84 from the cantilever 1. Keep it.

  At this time, the reflected light 84 reflected at a reflection angle of 26 ° travels in the air and is refracted by the parallel plane substrate 80 at a refraction angle of 16.9 °, and further travels from the parallel plane substrate 80 to the air at a refraction angle of 26 °. The light detector 13 is reached.

  Here, if the cantilever 1 is bent at an angle of 3 ° to the sample 18 side, the cantilever 1 is reflected at a reflection angle of 32 °, and the reflected light 84 is refracted by the parallel plane substrate 80 having a thickness of 3 mm originally inserted. It enters at 20.5 °, passes through the atmosphere again at a refraction angle of 32 °, and travels in the direction of the photodetector 13 along the optical path of the two-dot chain line 84b. At this time, the arrival position of the photodetector 13 is largely deviated as compared with the case where there is no warp. Therefore, in the present invention, the parallel plane substrate 80 having a thickness of 3 mm that was originally inserted in the optical path of the reflected light 82 is removed, and the parallel plane substrate 81 having a thickness greater than 3 mm is inserted. After passing through the substrate 81, it passes through the one-dot chain line optical path 84a, and the amount of deviation is corrected closer to the center than when passing through the parallel flat substrate 80 having a thickness of 3 mm.

  Considering the case where the cantilever 1 is bent by 3 ° on the opposite side to the sample 18, the reflected light 83 is reflected at a reflection angle of 20 °, and the reflected light 83 is refracted to the originally inserted parallel flat substrate 80 having a thickness of 3 mm. It enters at an angle of 13.1 °, passes through the atmosphere again at a refraction angle of 20 °, and travels in the direction of the photodetector 13 along the optical path of a two-dot chain line 83b. Also in this case, the arrival position of the photodetector 13 is greatly deviated compared to the case where there is no warp. Therefore, in the present invention, the parallel plane substrate 80 having a thickness of 3 mm that was originally inserted in the optical path of the reflected light 82 is removed, and the parallel plane substrate is omitted. Thereby, the reflected light passes through the optical path of the one-dot chain line 83a while maintaining the reflection angle of 20 °, and the shift amount is corrected closer to the center than when the parallel plane substrate 80 is inserted.

  With this configuration, even when the cantilever is warped, the amount of deviation can be corrected by the parallel plane substrate.

  As mentioned above, although the Example of this invention was described, this invention is not limited to these Examples.

  For example, in place of the cantilever, the present embodiment can be applied to a near-field microscope using a probe in which an optical fiber is sharpened, a metal coating is applied to the tip of the cantilever, and the tip is bent with respect to the long axis.

  Further, although the incident light has an incident angle of 0 ° with respect to the incident surface of the liquid level holding unit, a method of entering from an oblique direction may be used.

  Further, in the liquid level holding unit and the correction substrate, the light incident surface and the light emitting surface are not necessarily parallel planes.

Further, the liquid level holding unit and the correction substrate are not limited to quartz glass or BK7, and any medium can be used as long as it is transparent to the wavelength of the light source of the displacement detection mechanism. The greater the rate, the greater the correction effect.
In addition, the liquid level holding part and the correction substrate are laminated so that a plurality of materials are optically continuous, or a configuration in which a liquid medium is sandwiched between solid media and a plurality of correction substrates are used. In addition, the thickness of the incident light passage portion perpendicular to the incident light incident surface and the thickness of the reflected light passage portion perpendicular to the reflected light exit surface are different from those of the liquid surface holding portion. The present invention includes a configuration in which substrates for use are combined.

  Further, a light path switching mirror and a lens for image formation and light collection may be included in the optical path of the optical lever.

  Furthermore, the type of the solution is not limited to distilled water, and any solution can be used.

1 is an overview of a scanning probe microscope for measurement in air according to a first embodiment of the present invention. 1 is a schematic view of a scanning probe microscope for measuring in liquid according to the first embodiment of the present invention. It is an optical path diagram of the incident light to the cantilever of the displacement detection mechanism used in the first embodiment of the present invention. (A) It is a general-view figure of the scanning probe microscope for submerged measurement of the 2nd Example of this invention, (b) is a top view of the cantilever holder used for (a). It is a general-view figure of the scanning probe microscope for the measurement in the liquid used for the 3rd Example of this invention. It is a general-view figure of the scanning probe microscope for atmospheric measurement used for the 4th example of the present invention. It is a general-view figure of the conventional probe probe microscope for measurement in liquid.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 Cantilever 2 Probe 4 Atmospheric measurement cantilever holder 9 Main body base part 10 Displacement detection mechanism 11 Light source part 13 Light detection part 17 Optical microscope part 18 Sample 19 Sample holder 20, 107 Triaxial fine movement mechanism 21 Coarse movement mechanism 30, 50, 60 Cantilever holders for measurement in liquid 31, 51, 61, 102 Liquid level holding part 35, 111 Solution cell 36, 110 Solution (distilled water)
37, 55, 64 Incident light 38, 56, 65, 82, 83, 84 Reflected light 70, 80, 81 Parallel plane substrate

Claims (6)

A cantilever having a probe at the tip and a base at the end;
A sample holder for placing the sample to be measured, disposed at a position facing the probe; and
A displacement detection mechanism that includes a light source unit and a light detection unit, irradiates the back surface of the cantilever with light from the light source unit, and receives the reflected light from the cantilever with the light detection unit to detect displacement of the cantilever. And
A cantilever holder having a cantilever fixing portion for fixing a base portion of the cantilever, and a liquid level holding portion which is disposed above the cantilever and is made of a material transmissive to the light of the light source portion;
A solution cell for containing an arbitrary solution, and
The sample and the cantilever are disposed in the solution, the displacement detection mechanism is disposed in the atmosphere, and the surface on the side where the cantilever is installed of the liquid level holding unit is in contact with the solution and reaches from the light source to the cantilever. Incident light passes in the order of the atmosphere, the liquid level holder, and the solution, and the reflected light after being reflected by the cantilever passes through the optical path in the order of the solution, the liquid level holder, and the atmosphere. To the detector,
The thickness of the incident light passage part perpendicular to the incident surface of the incident light of the liquid level holding part is different from the thickness of the reflected light passage part perpendicular to the exit surface of the reflected light. A scanning probe microscope. In the liquid level holding part, the thickness of the reflected light passing part in the direction perpendicular to the outgoing surface of the reflected light is larger than the thickness of the incident light passing part in the direction perpendicular to the incident light incident face of the liquid level holding part The scanning probe microscope according to claim 1, wherein the thickness of the scanning probe microscope is increased. In the liquid level holding portion, at least a portion of the surface in contact with the solution through which incident light and reflected light pass is arranged on the same plane, and a surface in contact with the atmosphere through which incident light and reflected light pass are on the same plane. The scanning probe microscope according to claim 1, wherein the scanning probe microscope is configured so as not to exist. A cantilever having a probe at the tip and a base at the end;
A sample holder for placing the sample to be measured, disposed at a position facing the probe; and
A displacement detection mechanism that includes a light source unit and a light detection unit, irradiates the back surface of the cantilever with light from the light source unit, receives light reflected from the cantilever with the light detection unit, and detects displacement of the cantilever. When,
A cantilever holder having a cantilever fixing portion for fixing a base portion of the cantilever, and a liquid level holding portion which is disposed above the cantilever and is made of a material transmissive to the light of the light source portion;
A solution cell for containing an arbitrary solution, and
The sample and the cantilever are disposed in the solution, the displacement detection mechanism is disposed in the atmosphere, and the surface on the side where the cantilever is installed of the liquid level holding unit is in contact with the solution, and reaches the cantilever from the light source. Incident light passes in the order of the atmosphere, the liquid level holding part, and the solution, and the reflected light after being reflected by the cantilever is detected through the optical path in the order of the liquid, the liquid level holding part, and the atmosphere. To the department,
A scanning probe microscope characterized by being configured to insert a substrate that is transparent to the light of the light source unit in the optical path on the reflected light side in the atmosphere.   5. The scanning probe microscope according to claim 1, wherein the displacement detection mechanism is common for both measurement in the atmosphere and measurement in a solution. A cantilever having a probe at the tip and a base at the end;
A sample holder for placing the sample to be measured, disposed at a position facing the probe; and
A displacement detection mechanism that includes a light source unit and a light detection unit, irradiates the back surface of the cantilever with light from the light source unit, receives light reflected from the cantilever with the light detection unit, and detects displacement of the cantilever. When,
A cantilever holder having a cantilever fixing portion for fixing a base portion of the cantilever,
A scanning probe microscope characterized in that a substrate that is transparent to the light from the light source unit is disposed in the optical path on the reflected light side in an exchangeable manner.

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