JPH07234119A - Finely adjusting mechanism, scanning type probe microscope and infinitesimal displacement detecting method - Google Patents

Abstract

PURPOSE:To enhance fine adjustment detecting sensitivity of a scanning type probe microscope and to accurately measure finely adjusting coordinates by calculating a moving displacement of a flexible system from a detection signal from a single photoreceiving surface of a photoreceiver or detection signal of multisegment photoreceiving surfaces. CONSTITUTION:A laser light emitted from a focused beam light source 11 is reflected on an outer spherical mirror, and received by a quarter or split-half photoreceiving surface type photoreceiver 12. Photoelectric conversion outputs of the split photoreceiving regions are input to a signal differential amplifier 14 to detect axial output differences,DELTAEx-DELTAEz. These differences are all input to a calculator 18 to be calculated. A controller 16 calculates a deflection of a laser light spot of the surface of the photoreceiver 12 from the difference of the calculator 18, and obtains a displacement of a piezoelectric element l from the deflections of the respective axial directions. This relation is previously measured, its formula is obtained by the controller 16, and finely adjusting coordinates at the time of operating an external force of arbitrary magnitude can be accurately calculated from measured values of the DELTAEx-DELTAEz.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine movement mechanism having a minute displacement detecting device, a scanning probe microscope using the same, and a fine movement position detecting method.

[0002]

2. Description of the Related Art A scanning tunneling microscope has been developed as a means for observing the surface of an object more finely. A tunnel microscope is a phenomenon in which electrons can come and go between two conductors when the two conductors are brought close to the atomic size (nm size) by focusing on the “bleeding out” of the electron's wave function in a solid. Are using. In the case of a clean metal surface, the tunnel current flowing between both conductors flows about 1 nA when it approaches 1 nm, and the current value decreases by one digit when the distance between them increases or decreases by 0.1 nm. The scanning tunneling microscope scans the sample surface by maintaining the probe-sample distance so that the tunnel current value flowing between both conductors (between the metal probe and the sample to be measured) becomes constant. This is a mechanism for observing the surface roughness image of the sample.

Therefore, the probe (probe) is set to 0.1 n.
A technique is required to control the movement while finely moving with m accuracy. Since the development of the scanning tunneling microscope (STM), another surface roughness meter utilizing the quantum effect acting between the probe and the sample has been developed. Typical examples thereof are an atomic force microscope (AFM) and a magnetic force microscope (MFM).

The AFM utilizes an attractive force or a repulsive force based on a dispersion force acting between non-polar objects and is suitable for observing the surface of a non-conductive object. Further, the MFM is for observing magnetic domains and domain walls of a magnetic material sample and utilizes magnetic attractive force and repulsive force. Each of these quantum effect microscopes uses two
While scanning dimensionally, the surface roughness (or characteristic difference) of nm size is to be measured by scanning along the locus of the vertical movement of the probe.
PM).

In the scanning probe microscope, a fine movement mechanism is used for accurately grasping the fine movement position of the probe and controlling the movement thereof. The fine movement mechanism normally has one end fixed to the fixed portion (outer wall) of the microscope, and the external force is applied directly to a flexible jig with the other end having a probe in a free state, so that the Z-axis direction (probe / X axis perpendicular to the Z axis
There are a type in which the probe is moved in the -Y plane direction, and a type in which a device that is slightly moved by the action of an external force is sandwiched between the outer walls. In any case, in order to grasp and control the movement of the probe, a drive system for operating the probe with an accuracy of 0.1 nm or less and a detection system for quantitatively detecting the movement are required. .

The minute driving system often controls the movement by utilizing the relationship between the piezoelectric strain of the piezoelectric ceramics element and the applied voltage. As the detection system, in the case of STM, a device that electrically amplifies the tunnel current value is used, but in AFM and MFM, the movement of the free end of the flexible jig that is bent by the quantum force acting on the probe is expanded. A capture device is used.

The free end displacement measuring method includes a tunnel detection method using an STM probe, a light wave interference method using multiple interference of light, and light reflection at the free end which is received at a remote position and photoelectrically converted. An optical lever method and a piezo method using a strain sensor have been proposed and partially put into practical use.

As a measuring method for minute displacements using the optical lever method, for example, a measuring system using a combination of a lens, a reflecting sphere, and a light receiving element has been proposed (Ohara, Takamasu; 1991 Autumn Meeting of the Precision Engineering Society Conference). Conference Proceedings, 295-29
Page 6). In this method, He-Ne laser light is collimated by a convex lens, and the vibrating surface of the light is aligned by a polarization beam splitter, then squeezed by a first convex lens A, and the light is reflected by focusing on a reflecting sphere. It is bent in the orthogonal direction by a polarization beam splitter and then narrowed down by another second convex lens (C) to focus on the photoelectric conversion detector surface. The reflective spheres perpendicular to the optical axis the X-Y plane direction in this state (x _d, y _d) when displacing the displacement on the detector surface (2kX _d, 2k
It uses the principle of being extended to y _d ). Here, k is the focal length of the convex lenses A and C, respectively.
_{Letting a} and f _c be constants given by f _c / f _a .

[0009]

Among the detection systems in the fine movement mechanism of the SPM described above, the piezo system in which the displacement detection sensor is directly installed in the flexible system is disclosed in, for example, Japanese Patent Publication No. 4-7250.
As described in No. 4, a piezoelectric thin film element is formed on the upper surface of the cantilever, and a phenomenon in which the current flowing through the element changes due to piezoelectric strain is amplified and detected. There is also an attempt to detect by photoelectrically converting and amplifying the amount of change in the amount of light passing through the thin film optical path attached to the lower surface of the cantilever due to the displacement of the cantilever.

However, it is difficult for these methods to detect the displacement with a high resolution such as 1 nm or less.
A method of attaching a high-precision displacement gauge such as a laser displacement gauge to a flexible jig can be considered to increase the resolution, but this is not realistic because it miniaturizes the flexible jig and significantly impairs the minute driving capability.

Of the SPM detection systems described above, the method that does not directly contact the flexible jig is highly practical. However, in the tunnel detection method in which the tunnel current probe is placed close to the back surface of the cantilever, the detection sensitivity is limited because the force is exerted on the lever through various molecules adsorbed on the lever surface, and its operation becomes unstable. There is a drawback. On the other hand, in light wave interferometry and optical lever method using light, the radiation pressure of light is very small (radiation pressure of light of 1 mW is 7 × 10 ^-12 N) and the force of the detection system exerted on the lever is actually Can be ignored.

However, since the detection system using light uses photoelectric conversion as a photodetector, if the change in light quantity is small, S
The / N ratio decreases and the movement of the flexible jig cannot be captured with sufficient accuracy. As a result, a burden is placed on the flexible jig. That is, a flexible jig having high followability with respect to the surface unevenness of the sample to be measured is required. For this reason, the sharpness of the tip shape of the probe, the material of the flexible support portion, the film thickness, and the mechanical strength become problems, and the processing accuracy and durability of the flexible jig often become difficult. Has been done.

For example, in the above-mentioned optical lever system using the lens / reflection sphere / light-receiving element combination, the magnification of the light-receiving surface of the light-receiving element is 2K = 2f _c / f _a with respect to movement in the X and Y axis directions. If f _a → small and f _c → large, the magnification increases, but in consideration of practicality, the minimum value of f _a is limited to about 4 mm. Therefore, in order to increase the movement distance on the light receiving surface of the light receiving element 100 times (= 10 μm) in order to detect a minute displacement of 0.1 μm, f _c is 200 mm from the above formula with respect to this f _a minimum value. Therefore, it is unsuitable for a compact minute displacement detection system, particularly for a fine movement device detection device applicable to SPM.

According to this optical lever system, He-N
e Laser light is used for polarization beam splitter and phase control 1
Since the light is transmitted back and forth (twice) through the / 4 wavelength plate, the intensity on the light receiving surface of the light receiving element is significantly reduced. As a result, the S / N ratio is reduced, which causes a problem of detection sensitivity reduction including an error during photoelectric conversion.

An object of the present invention is to reduce the size of the detection system of the fine movement mechanism of the SPM and to increase its sensitivity more than before, thereby relaxing the requirements for material and processing precision required for the flexible jig of the fine movement mechanism. It is to provide a mechanism.

Another object of the present invention is to provide an SPM incorporating the above-mentioned fine movement mechanism with high detection sensitivity, and to provide a method for detecting a minute displacement thereof.

[0017]

According to the present invention, a flexible system having a fixed end fixed to an outer wall and a moving end finely moved by the action of an external force, and a spherical surface fixed to the moving end of the flexible system. A mirror, a focused beam light source for irradiating a focused beam of light to one point of a spherical mirror, and a single light receiving surface type or multi-divided light receiving surface type light receiving element for receiving the reflected light, and the focused beam light source and the light receiving element A flexible system based on a detection signal from a single light-receiving surface of a light-receiving element of the optical detection system or a detection signal from the multi-divided light-receiving surfaces of the optical detection system, which is installed at predetermined positions on the outer wall at predetermined intervals. There is disclosed a fine movement mechanism including means for calculating the movement displacement of.

Further, according to the present invention, a flexible system having a fixed end fixed to the outer wall and a moving end finely moved by the action of an external force, a spherical mirror fixed to the moving end of the flexible system, and a spherical mirror. A plurality of focused beam light sources that irradiate focused beam light from different directions to each other, and a plurality of light receiving elements that receive the reflected light and that are paired with the focused beam light source. A plurality of pairs of optical detection systems in which a light source and a light receiving element are installed at predetermined positions different from each other on the outer wall and at predetermined intervals, and a moving displacement of a flexible system from detection signals of the light receiving elements of the plurality of pairs of optical detection systems. And a fine movement mechanism including the means for calculating.

Further, according to the present invention, a flexible system having a fixed end fixed to the outer wall and a moving end finely moved by the action of an external force, a spherical mirror fixed to the moving end of the flexible system, and a spherical mirror. A plurality of focused beam light sources for irradiating focused beam light from different directions to each other, and a plurality of multi-divided light receiving surface type light receiving elements for pairing with the focused beam light source, which receive the reflected light, A plurality of pairs of focused beam light sources and a multi-divided light receiving surface type light receiving element are installed at predetermined positions different from each other on the outer wall at predetermined intervals, and a multi-division of the plurality of pairs of optical detection systems. Disclosed is a fine movement mechanism including means for calculating the movement displacement of the flexible system from the detection signal of the light receiving surface type light receiving element as independent values with interference components removed.

According to the present invention, a flexible system having a fixed end fixed to an outer wall and a moving end finely moving in a maximum of three axial directions by the action of an external force, and a spherical surface fixed to the moving end of the flexible system. A mirror and a first focused beam light source that sends focused beam light to a spherical mirror, which is fixedly installed at a predetermined interval at an outer wall position capable of detecting displacement along one plane in one of the three axes of the moving end; A four-division light-receiving surface type light-receiving element that receives this reflected light from the outer spherical surface, and an outer wall position that can detect displacement along a plane perpendicular to the above-mentioned one plane at the moving end, are fixedly installed at predetermined intervals. A second focused beam light source for sending the focused beam light to the spherical mirror and a four-division light receiving surface type light receiving element for receiving the reflected light from the outer spherical surface, and a light receiving surface of the first four division light receiving surface type light receiving element. Detects parallel displacement of moving end as output change in each light receiving area , The displacement of the moving end, which is parallel to the light receiving surface of the second four-division light receiving surface type light receiving element, is detected as an output change in each light receiving area, and the three-axis movement displacement of the flexible system is interfered from these detection signals. Disclosed is a fine movement mechanism including means for calculating values independent of each other with components removed.

Further, according to the present invention, the movable end is displaceable in three axial directions of X, Y, Z (X, Y are coordinate axes along the plane of the movable end, and Z is a coordinate axis perpendicular to this plane) with respect to the fixed end. A flexible piezoelectric system, a spherical mirror fixed to the moving end of the flexible system, and an outer wall position capable of detecting a displacement along one plane of the three axes of the moving end at predetermined intervals. A fixed first fixed beam light source for sending the focused beam light to the spherical mirror, a four-division light receiving surface type light receiving element for receiving the reflected light from the outer spherical surface, and a plane perpendicular to the one plane at the moving end. A second focused beam light source for sending focused beam light to a spherical mirror and a four-division light receiving surface type for receiving the reflected light from the spherical surface, which is fixedly installed at a predetermined interval at an outer wall position along which displacement can be detected. The light receiving element and the moving end parallel to the light receiving surface of the first four-division light receiving surface type light receiving element The displacement is detected as an output change in each light receiving area, the displacement of the moving end parallel to the light receiving surface of the second four-division light receiving surface type light receiving element is detected as an output change in each light receiving area, and these detections are made. Disclosed is a fine movement mechanism including means for calculating the triaxial movement displacement of a flexible system from a signal as mutually independent values with interference components removed.

Further, according to the present invention, the moving end is displaceable in the three axis directions of X, Y, Z (X, Y are coordinate axes along the plane of the moving end, and Z is a coordinate axis perpendicular to this plane) with respect to the fixed end. A flexible piezoelectric system, a spherical mirror fixed to the moving end of the flexible system, and an outer wall position capable of detecting a displacement along one plane of the three axes of the moving end at predetermined intervals. A fixed first fixed beam light source for transmitting the focused beam light to the spherical mirror and a four-division light receiving surface type light receiving element for receiving the reflected light from the spherical surface, and a plane perpendicular to the one plane at the moving end. Fixed along the outer wall position where the displacement along it can be detected at a predetermined interval,
A second focused beam light source for sending the focused beam light to the spherical mirror and a four-division light receiving surface type light receiving element for receiving the reflected light from the spherical surface, and at least any one of X, Y and Z is provided in the piezoelectric scanner. A voltage is applied to give a displacement in the direction of one axis, causing a displacement at the moving end of the piezoelectric scanner,
In this displacement, the displacement of the moving end, which is parallel to the light receiving surface of the first four-division light receiving surface type light receiving element, is detected as an output change in each light receiving region, and the second four-division light receiving surface type light receiving element is detected. The displacement of the moving end, which is parallel to the light receiving surface of the element, is detected as an output change in each light receiving region, and the triaxial moving displacement of the flexible system is calculated from these detection signals as mutually independent values with interference components removed. A small displacement detection method for a piezoelectric scanner is disclosed.

Further, according to the present invention, the three-axis movement displacement is

[Equation 3] I decided. Further, the present invention discloses a scanning probe microscope using the fine movement mechanism.

[0024]

In the present invention, a spherical mirror is provided at the moving end of the flexible system, and the displacement of the flexible system is detected by utilizing the focused beam light source and the light receiving element from a fixed position. This allows the displacement of the flexible system itself to be detected. As the light receiving element, there are a single light receiving surface type and a plurality of divided light receiving elements such as a four-divided light receiving surface type. The four-division light-receiving surface type light-receiving element is suitable for detecting displacements on the light-receiving surface in two directions orthogonal to each other. Further, according to the present invention, an optical detection system including a focused beam light source and a four-division light receiving surface type light receiving element is fixedly arranged at a position orthogonal to each other with respect to the spherical mirror. Then, the displacements of the spherical mirrors on the two orthogonal planes are detected by the corresponding optical detection systems. After that, the displacements in the X, Y, and Z coordinate systems are calculated as independent values.

[0025]

EXAMPLES The present invention will now be described in more detail based on examples. FIG. 1 is a perspective view showing the main components of the fine movement mechanism according to the embodiment. It should be noted that the hatching of each electrode surface in the figure is to make the figure easier to see. The same applies to FIG. 2 and the like described later. In FIG. 1, reference numeral 1 denotes a piezoelectric element, which constitutes a flexible system together with the outer spherical mirror 10. The piezoelectric element 1 is
It is composed of a hollow piezoelectric ceramic cylinder and a plurality of electrodes electrically and independently arranged on the inner and outer circumferential surfaces thereof. Four of the electrodes are inner peripheral electrodes, which are used as common electrodes (ground electrodes) when driving each axis. Further, 5x ₁ (not shown) and 5x ₂ are X-axis direction displacement electrodes arranged along the X axis of the hollow piezoelectric ceramic cylinder, and 5y ₁ and 5y ₂ are along the Y axis of the cylinder. It is the arranged electrode for Y-axis direction displacement. Further, 5z is a Z-axis displacing electrode which is arranged seamlessly along the cylindrical circumferential surface.

The upper end surface 2 of the hollow piezoelectric ceramic cylinder is fixed to an outer wall (not shown), while the lower end surface 3 is a free end (moving end) provided with a probe or the like. A bottom plate 6 for attaching the outer spherical mirror 10 is attached to the lower end surface 3.
As shown in the drawing, the outer spherical mirror 10 has a hemispherical shape arranged around the Z axis at the center of the cylinder (radius r ₀ ).

On the other hand, a pair of focused beam light source 11 and four-division light receiving surface type light receiving element 12 are fixedly installed at a predetermined distance on the outer wall in the inner region of the cylinder. 11 and 12
Is arranged so that the focused beam light emitted from 11 is reflected by the outer spherical mirror 10 and the reflected light is reliably received by the four-division light receiving surface of 12.

FIG. 2 is a diagram for explaining fine movement of the moving end of the piezoelectric element 1 shown in FIG. In the figure, a side view as seen from the XZ plane of the cylinder is shown. Figure 2 (A)
Shows the case where no voltage is applied between any electrodes of the cylinder. The cylinder is not deformed because no piezoelectric strain is induced. FIG. 2B shows a case where an electrode having a direction in which tensile strain acts on a cylinder is applied between the electrodes 4-5z. It is shown that the piezoelectric element 1 extends in the Z-axis direction. Although not shown, if the polarity of the applied voltage is reversed, the piezoelectric element 1 contracts in the Z-axis direction.

On the other hand, FIG. 2C shows a state where the cylinder is bent in the X-axis direction. In this case, electrodes 4-5x
A voltage having a polarity inducing compressive strain is applied between the _two electrodes, and a voltage having a polarity inducing tensile strain is applied between the electrodes 4-5x ₁ . Although not shown, the Y-direction displacement can be similarly generated.

As can be understood from FIG. 2C, the fine movement of the XY plane using the piezoelectric ceramic cylinder in the proper direction is always accompanied by a slight rotation about an axis perpendicular to the displacement direction. .

The focused beam light source 11 shown in FIG.
-It may be an optical fiber that guides a Ne laser to the position. The light emission direction can be easily adjusted by adjusting the emission surface of the optical fiber.

FIG. 3 shows the light receiving surface of the four-division light receiving surface type light receiving element 12 of FIG. 1 and the beam light intensity distribution on the light receiving surface. The light-receiving surface is a four-divided region 1 having a uniform area and uniform light-receiving sensitivity.
3a, 13b, 13c, 13d. A region separation groove is cut between each light receiving region. The respective light receiving regions are arranged along the X-axis and Y-axis directions of the cylinder as shown in the figure.

Each light receiving area 13a, 13b, 13c, 13
The photoelectric conversion outputs of d are Ea, Eb, Ec, and Ed, respectively. The light intensity distribution in the radial direction of the laser beam spot on the light receiving surface is normally a Gaussian distribution, as shown by the solid line in FIG. However, in the following description, for simplicity, it is approximated that the light intensity distribution of the beam spot is uniform as shown by the broken line in FIG. The photoelectric conversion output of each region is proportional to the amount of received light for laser beam light having the same emission spectrum. When the laser beam light is incident on the light receiving surface across the line X ₁ -X _{2 in} FIG.

[Equation 4] It is represented by. By detecting a photoelectric conversion output difference Delta] E _x corresponding to the difference between the left and right of the light quantity of X ₁ -X _2, it is possible to detect the displacement of the X-axis direction illustrated. On the other hand, when the laser beam light is incident on the light receiving surface across the line Y ₁ -Y _{2 in} FIG.

[Equation 5] The displacement in the Y-axis direction shown in the figure can be detected by detecting the difference ΔE _y between the light amounts above and below Y ₁ -Y ₂ .

When the laser beam is initially in the neutral position, the center of the laser beam light should be adjusted near the intersection of X ₁ -X ₂ and Y ₁ -Y ₂ in FIG. 3, that is, the beam spot should be adjusted to the position 14a. desirable. Even if the laser beam light is shifted in a direction that forms an appropriate angle with the X and Y axes, the X axis and the Y axis can be measured by measuring both ΔE _x and ΔE _y expressed by (Equation 4) and (Equation 5).
Axial displacement can be detected.

For example, as shown in FIG. 3A, assume that the laser beam spot shifts from the neutral position by Δx in the X-axis direction and the spot shifts from 14a to 14b. If the total value of the areas (shaded areas in the figure) increased in 13a and 13d by the shift is ΔS, then (E _a + E _d ) is C ₁ Δ
S (where C ₁ is a proportional constant) increases, and conversely (E _b + E
_c ) is reduced by C ₁ ΔS. As a result, ΔE _x shown in (Equation 4) changes by 2C ₁ ΔS due to the shift of Δx.
That is, ΔE _x is an output proportional to the area change ΔS. On the other hand, when the change amount Δx is small, it may be considered that ΔS is almost proportional to Δx, and C ₂ is a constant of proportionality.

[Equation 6] Becomes Further, even if Δx is not very small, ΔE _x and Δx are functions having a certain relation, and in any case ΔE _x
Δx can be detected by measuring

Δ detected by the four-division light receiving surface type photodetector 12
Since E _x and ΔE _y are actually high-sensitivity amplified values through a differential amplifier (not shown), it is necessary to detect about 0.1 μm as the moving distance of the laser beam light spot on the light receiving surface. Is also possible.

FIG. 9 shows an example of the output characteristic of the four-division light receiving surface type light receiving element (photodiode) 12 shown in FIG. 3 with respect to the laser light spot displacement. However, the light-receiving element output on the vertical axis in the figure indicates the output value after passing through the differential amplifier with an amplification factor of 100 times. According to FIG. 9, it is 2 for 1 μm spot displacement.
An output change of 1.5 mV can be obtained. When measuring this output change with a general-purpose 12-bit AD converter (0 to 5 V), the converter resolution is 1.22 mV / bit, so 1.22 (mV / bit) /21.5 (mV / μ)
m) = 0.057 (μm / bit), which is sufficiently 0.1
The displacement can be measured with a resolution of μm.

FIG. 6 is a perspective view of the main components of the fine movement mechanism in an embodiment different from FIG. 1 of the present invention. The outer spherical mirror provided on the lower end surface 3 of the piezoelectric element 1 is fixed to the central portion of the bottom plate in the embodiment of FIG. 1, but in the case of this embodiment, the tip of the protrusion 7 (in the XY plane) outside the cylinder. It is fixed to. Therefore, the focused beam light is emitted outside the cylinder, not inside the cylinder.

In FIG. 6, a pair of focused beam light sources and a four-divided light receiving surface type light receiving element are arranged on the outer wall (not shown) in such directions that the focused beam lights entering and reflected by the outer spherical mirror 10 are substantially orthogonal to each other. No.) is fixed in place.

Reference numerals 11xy and 12xy denote a focused beam source and a four-divided light receiving surface type light receiving element for measuring the X-Y plane displacement, and 11zx and 12zx, a focused beam source and a four-divided light receiving unit for the ZX plane displacement measurement, respectively. It is a planar light receiving element. The outputs of the light receiving elements 12xy and 12zx are connected so as to be input to the analog circuit 18A of the arithmetic unit 18 at the same time.

The arithmetic unit 18 determines the area difference Δ of the light receiving element.
An analog circuit 18A for inputting E _x , ΔE _y , and ΔE _z ,
It is composed of an A / D converter 18B that converts an analog voltage value into a digital signal, and an arithmetic circuit 18C that calculates displacements of three axes independently, and the calculated displacement is output as a highly accurate minute displacement value.

The focused beam sources 11xy and 11zx correspond to, for example, the emission ends of an optical fiber into which He-Ne laser light is introduced. The beam emission direction is adjusted so that the focused beam light is incident on the apex of the outer spherical mirror 10 when piezoelectric strain is not applied to the piezoelectric element 1. Next, the principle of measuring the displacement using the outer spherical mirror 10 of FIG. 6 will be described.

FIG. 4 is a top view of the outer spherical mirror 10 in FIG. 6 viewed from the Z-axis direction. First, when no voltage is applied to each electrode in FIG. 6, the laser beam light is adjusted in position so as to be reflected at point 0 (vertex of outer spherical mirror 10) in FIG. Next, the inner peripheral electrode 4 of FIG.
And outer electrodes 5x _1, 5x _2, 5y _1, predetermined polarity 5y _2, the result of applying a predetermined magnitude of voltage, distorted lower end surface 3 of the piezoelectric element 1, the outer spherical surface mirror 10 of the laser beam
It is assumed that the apex of moves to the point 0 _{1 in} FIG. The 0 ₁ point is a position shifted from the X axis by the angle α and from the 0 point by Δr in distance. Laser beam light source 11xy,
11zx and four-division light-receiving surface type light-receiving elements 12xy, 12z
Since x is fixed, the reflection point on the outer spherical mirror 10 remains at 0 point. A top view of the moved outer spherical mirror 10 is shown by a dotted line.

When the displacement amounts of the outer spherical mirror 10 in the X and Y axis directions are Δx and Δy, respectively, the following equation is established.

[Equation 7]

FIG. 5 is a diagram showing the relationship between incidence and reflection of a laser light beam on a plane including the line A ₁ -A _{2 of} FIG. 4 and the Z axis of FIG. However, in the figure, the laser beam light source 11xy and the four-division light receiving surface type light receiving element 12xy, and the incident beam and the reflected beam are projected and drawn in the plane of the figure.

Before the deformation of the piezoelectric element 1, it is assumed that the laser light beam is incident on the point 0 (the apex of the outer spherical mirror 10 at this time) at the angle θ. At this time, the Z ′ axis parallel to the Z axis passes through the zero point, and the angle θ represents the inclination from the Z ′ axis. The reflection angle is also θ, and the reflected beam is incident on the four-division light receiving surface type light receiving element 12xy located at a distance L from the 0 point, and is reflected by lines X ₁ -X ₂ and Y ₁ -Y _{2 in} FIG. Photoelectric conversion is performed in each of the light receiving regions 13a to 13d of the light receiver 12 such that the center of the beam spot is substantially at the intersection.

Now, it is assumed that the piezoelectric element 1 is distorted and the moving end, and hence the outer spherical mirror 10 is shifted by Δr.
Since the vertex 0 ₁ of the outer spherical mirror 10 shifts in the moving direction as shown by the dotted line in the figure, the tangent plane at the 0 point (the entrance / reflection point of the laser light beam) is inclined by Δψ.
As a result, the incident beam angle with respect to the vertical line passing through the 0 point standing on this tangent plane (the plane that is in contact with the spherical surface at 0 point) is (θ + Δ
ψ), and the reflection angle is also (θ + Δψ). That is, Δ
Due to the outer spherical mirror shift of r, the reflected beam from the point 0 is inclined by (θ + 2Δψ) with respect to the Z axis. Of course, the incident beam angle to the 0 point is invariable (θ) with respect to the Z axis.

As a result, the four-division light receiving surface type light receiving element 12x
The light receiving beam spot on the light receiving surface of y (see FIG. 3) is deflected by Δb = 2Δφ · L in the direction opposite to the moving direction of the piezoelectric element 1 by the principle of light lever. In FIG. 4, the focused beam light source 11xy and the light receiving element 12xy are described by projecting them on the paper surface. Therefore, the incident / reflection angle θ of the focused beam light with respect to the Z axis projected on the paper surface is also different from the actual incident / reflection angle shown in FIG. 1, but the magnitude of θ is the deviation Δb of the focused beam spot on the light receiving surface of the light receiver. Is not relevant, the conclusions drawn in FIG. 4 are not affected. However, Δr
Is a small displacement, so that r ₀ >> Δr, that is, Δ
ψ is minute.

Below, Δφ is obtained as a function of distance.
In FIG. 5, the coordinates showing the position of the outer spherical mirror 10 shifted by the deformation of the cylindrical piezoelectric element 1 are represented by (x _a , y _a ).
Then the semicircle shown is the equation

[Equation 8] It is the upper half of the circle represented by. When y _a is obtained from this equation,

[Equation 9] When this equation is differentiated by x _a and the equation expressing the inclination of the point on the circumference is obtained,

[Equation 10] In (Equation 10), the slope of the point on the circumference when x _a = Δr is Δψ
Therefore,

[Equation 11]

Here, considering Δr / r ₀ << 1,

[Equation 12] Is obtained. Therefore, the deflection of the focused beam light spot on the light receiving surface of the light receiving element is

[Equation 13] Becomes 4-division light receiving surface type light receiving element 12xy shown in FIG.
X of the laser beam spot on the light receiving surface of the deflection of the Y-axis direction, respectively [Delta] b _x, if [Delta] b _y,

[Equation 14]

[Equation 15] Therefore, by substituting the relationships of (Equation 7) and (Equation 13),

[Equation 16] Becomes Actual shakes Δx and Δy are (2L /
r ₀₎ multiplied (referred to as a lateral magnification) enlarged shake [Delta] b _x and [Delta] b _y, and the deviation Delta] E _x and Delta] E _y of the photoelectric conversion output of the light receiver 12 to the result generated, (Equation 4), (the number It is measured as shown in 5) and is detected with high sensitivity through the differential amplifier.
Therefore, in advance,

[Equation 17] Can be calculated using (Equation 6) or can be obtained experimentally, and an arbitrary Δr shift that occurs when an external force acts can be obtained from F ⁻¹ (ΔE _x , ΔE _y ). . For example, when r ₀ = 1 mm and L = 50 mm, Δx =
If it is 1 nm, it is observed by being enlarged to Δb _x = 100 nm (= 0.1 μm) on the light receiving surface of the light receiver by the optical lever method. The deflection of the beam spot is a value that can be detected by using the differential amplifier and the A / D converter as estimated above. That is, it becomes possible to detect the displacement of the outer spherical mirror with a resolution of 1 nm.

In the conventional example of the combination of the lens / reflecting sphere / light receiving element described above, in order to magnify the beam spot displacement on the light receiving surface of the light receiver by 100 times, the distance between the lens C ′ / light receiving element must be 200 mm. Notwithstanding, the device including the polarization beam splitter, the lens A, and the quarter-wave plate was enlarged. However, in this example, these optical parts are not required to obtain the same magnification, and the distance L between the reflecting sphere and the light receiving element is shortened to 1/4, which is a great effect for downsizing the fine motion detection system. Further, in the case of the present invention, since the polarization beam splitter is not used, the laser beam is not attenuated, and the intensity of the beam spot on the light receiving surface is sufficiently high, so that the detection sensitivity is high.

From (Equation 16), the shake of the laser beam spot on the light receiving surface and the X axis due to the piezoelectric strain of the piezoelectric element 1,
Since the Y-axis direction shift is in a proportional relationship, the XY in-plane shift of the moving end due to piezoelectric strain, that is, the translational motion components Δx and Δy.
Can be detected independently of each other.

Based on the principle described above, the displacement of the outer spherical mirror 10 in FIG. 6 in the X and Y directions can be detected from the output of the four-division light receiving surface type light receiving element 12xy. In exactly the same manner, the displacement of the outer spherical mirror 10 in the Z and X directions can be detected from the output of the four-division light receiving surface type light receiving element 12zx in FIG.

However, as shown in FIG. 2C, the shift of the moving end in the XY plane due to the piezoelectric strain is the displacement in the Z-axis direction (the displacement due to the interference), and the shift in the Z-X plane is the Y.
Since displacement in the axial direction (displacement due to interference) is involved, it is not possible to detect the displacement amount with high accuracy unless the correction is performed. For example, simply displacing only in the Z direction causes the twisting of the beam on the light receiving surface as shown in (Equation 21). Due to this twist, a detection signal is output from each divided surface of the light receiving element, and it is calculated by simple calculation as if it were displaced in the X and Y directions. If this is called an interference component, the determinants after (Equation 26) are used to remove this interference component. The equations after (Equation 26) are equations for independently calculating the displacement components of the three axes. Hereinafter, the influence of the unintentional displacement (that is, interference) in the axial direction orthogonal to the plane in which the intentional shift is performed on the output of the four-division light receiving surface type light receiving element is described, and further each displacement calculation method is disclosed. In the embodiments, a method capable of removing an interference component and accurately detecting the amount of movement for each axis, a fine movement mechanism (using it), and a microscope are disclosed.

With the mechanism shown in FIG. 6, the output change of the four-division light receiving surface type light receiving element 12xy when the spherical mirror 10 is shifted parallel to the Z axis will be evaluated. An explanatory view corresponding to FIG. 5 is shown in FIG. In FIG. 12A, a dotted line shows a state where outer spherical mirror 10 in the neutral position shown by the solid line is shifted by Δz only in the Z-axis direction. As shown, the focused beam source 11
Since the incident beam from xy is unchanged, the beam incident point on the outer spherical mirror 10 is changed from 0 to 0 ₂ by the shift of Δz.
Move to the point. As a result, the tangent plane of 0 ₂ points is inclined by Δφ _Z as compared with the tangent plane at 0 points as in the shift of FIG. Therefore, the shift of the focused beam spot (beam deflection) Δb on the light receiving surface of the four-division light receiving surface type light receiving element 12xy.
_Z is the shift Δb due to the parallel movement of the reflection point in the Z-axis direction.
_It is the sum of _Z1 and the shift Δb _Z2 due to the inclination Δψ _Z of the outer spherical mirror 10 at the reflection point.

FIG. 12B is an enlarged view of the outer spherical mirror 10 near the reflection point of the focused beam. Since Δz is an unintentional shift, it can be approximated to be sufficiently smaller than the radius of curvature r ₀ of the outer spherical mirror 10. That is, a straight line can be approximated between O ₂ B indicated by the dotted line. This allows

[Equation 18] Becomes

Next, Δb _Z2 is calculated. The inclination Δψ _Z of the outer spherical mirror tangent plane of the reflection point O ₂ is given by (Equation 11)

[Formula 19] Therefore, the beam deflection Δb _Z2 due to Δψ _Z is

[Equation 20] From (Equation 18) and (Equation 20), Δb _Z is

[Equation 21]

The same applies to the unintentional displacement Δby in the Y-axis direction when the moving end is shifted in the Z-X plane (in this case, the change in the output of the 4-divided light receiving surface type light receiving element 12zx). Unlike the case of the intentional displacement as shown in (Equation 16), these unintentional displacements have the incident angle θ dependence of the focused beam on the outer spherical mirror.

The unintentional displacement in the Z-axis direction expressed by (Equation 21) is eventually the output ΔE of the 4-division light-receiving surface light-receiving element 12xy.
It is divided into x and ΔEy and behaves as if the outer spherical mirror 10 were displaced in the X and Y axis directions.

This error can be eliminated as follows. First, let us say that the light receiving area output differences shown in (Expression 4) and (Expression 5) of the 4-division light receiving surface type light receiving element 12xy for XY plane displacement measurement are ΔE _1x and ΔE _1y , respectively. Similarly Z-
The light receiving area output differences of the light receiving element 12zx for X-plane displacement measurement are set as ΔE _2z and ΔE _2x , respectively. Then, the displacements of the outer spherical mirror 10 in the X, Y, and Z axis directions are respectively U _x ,
Let U _y and U _z .

As described above, ΔE _1x is the displacement output in the X-axis direction, but is influenced by the unintentional displacement in the Z-axis direction. However, it is not affected by the displacement in the Y-axis direction. Therefore,

[Equation 22] Can be expressed as Similarly, ΔE _1y , ΔE _2z , and ΔE _2x

[Equation 23]

[Equation 24]

[Equation 25] It can be expressed as. Where C ₂₂ , C ₂₃ , C ₃₂ ,
C ₃₃ , C ₄₁ , and C ₄₂ are constants. However, each of these constants includes the incident angle θ of the focused beam on the outer spherical mirror, as is clear from (Equation 21). Therefore, it is necessary to fix θ in advance and obtain it by actual measurement.

Now

[Equation 26]

[Equation 27]

[Equation 28] And the matrix is a constant, (Equation 22) to (Equation 25) are summarized as

[Equation 29] Can be written. If you expand this,

[Equation 30] Where C ^T is the transposed matrix of C and (C ^T · C) ⁻¹ is (C
Shows the ^T · C) of the inverse matrix.

If (Equation 30) is used, the light receiving element 12x
By using a total of four outputs of y and 12zx, the X, Y, and Z axial displacements can be accurately and independently obtained by removing the interference components.

In the embodiment shown in FIG. 6, a minute displacement in the X-axis direction is detected by both the four-division light receiving surface type light receiving elements 12xy and 12zx. As described above, when the outer spherical mirror 10 is arranged on the lower end surface of the piezoelectric element 1, the piezoelectric element 1
Is driven to perform an intentional displacement in the X-axis direction, an unintentional displacement in the Z-axis direction is accompanied. Therefore, four output values from the two light receiving elements are necessary for the calculation. However, when the flexible system of the fine movement mechanism has a structure that can perform displacement in only one direction, the combination of the pair of focused beam light sources and the four-division light receiving surface type light receiving element is required. It is possible to simplify the combination of one pair to the focused beam light source and the two-divided light receiving surface type light receiving element instead of the detection system using two pairs.

In addition to the above-described combination of two pairs of focused beam light sources and light receiving elements, it is also possible to use a combination of three pairs of focused beam light sources and two split light receiving surface type light receiving elements. When the obtained output values are simultaneously input to the arithmetic device and the above-mentioned arithmetic operation is performed, highly accurate displacement coordinates (Δx, Δ
y, Δz) is obtained.

In the above description, the outer spherical mirror 10 is
Although it is assumed to be a perfect hemisphere, it is self-evident that only the region for reflecting the focused beam and its vicinity may be spherical with a radius r ₀ .

The input / output linearity of the light receiving element 12 shown in FIGS. 1 and 6 is 0.1% as shown in FIG. 10 (Source: Hamamatsu Photonics Co., Ltd., Photodiode Catalog, 1992, page 13). Since it can be kept below 10 ^-3 ),
The displacement detection accuracy by this method can be in the order of 0.1%.

FIG. 11 shows an example of data obtained by using the fine movement mechanism and the measurement system shown in FIG. FIG. 11 shows the piezoelectric element 1.
5 shows the photodetector output (vertical axis) of the four-division light-receiving surface type light-receiving element 12 with respect to the minute displacement amount (horizontal axis) of the lower end surface 3 of FIG. However, the vertical axis represents the value obtained through a 100-fold differential amplifier. In this case, r ₀ = 1 mm and L = 50 mm.
The displacement amount on the horizontal axis of the figure is detected by a capacitance type displacement sensor (resolution 0.01 μm or less). It has been shown to be a system that can measure minute displacements with high sensitivity.

By repeatedly using the optical lever method, it is possible to further increase the deflection of the focused beam spot on the light receiving surface of the light receiving element. For example, in FIG.
An example is shown in which an outer spherical mirror 10 (having a radius r ₀ ) is used. In FIG. 5, a second outer spherical mirror is arranged at a position where the light receiving element 12 is arranged (a position at a distance L from the first outer spherical mirror 10) to reflect the light, and the first outer spherical mirror 10 is further reflected.
The third outer spherical mirror is arranged at the same position on the XY plane as the above (a position separated from the second outer spherical mirror by a distance L), and is reflected once again, and this reflected light is reflected by the second outer spherical mirror. The light is made incident on the four-divided light-receiving surface of the light-receiving element 12 fixed at the same position on the XY plane as the spherical mirror (a position separated from the third outer spherical mirror by a distance L). As a result, the optical lever is used in three stages, and the deflection Δb of the focused beam light spot on the light receiving surface of the light receiving element is

[Equation 31] Therefore, the one-digit deviation can be enlarged as compared with the example of FIG. That is, the detection sensitivity can be increased accordingly.

According to the embodiment of FIG. 6 described above, it is possible to accurately measure the displacement coordinate of the fine movement mechanism on the XY plane. That is, since the spherical mirror is used as the detecting element of the movable portion, even if the movable portion rotates as shown in FIG. 2C, the spherical mirror 10 does not affect the rotation at all. Only purely translational component displacements can be detected.

In each of the above embodiments, the light reflection of the outer spherical mirror is used, but the same applies when a concave spherical mirror is used.
Further, if the displacement coordinates (Δx, Δy) of the light reflection point and the curved surface curvature r ₀ (var) at that position are all measured in advance, it is possible in principle to use a mirror having a curvature other than a spherical surface. is there. The idea is to use a mirror having a surface of a rotating body obtained by rotating an arbitrary curve having a curvature on an axis perpendicular to the X and Y planes. Further, other elements that replace the four-division light receiving surface type light receiving element are possible.

FIG. 7 is a block diagram of a control and measurement circuit for the flexible system and the detection system by the fine movement mechanism of the present invention described above. The displacement of the piezoelectric element 1 that has driven the piezoelectric element driving circuit 17 due to piezoelectric strain is caused by the laser beam emitted from the focused beam light source 11 including the optical fiber emitting end into which the laser beam emitted by the driving of the laser oscillation circuit 15 is introduced. Is reflected by the outer spherical mirror 10 fixed to the moving end 3 of the piezoelectric element 1, the displacement is enlarged by using the optical lever method, and the light is received by the four-division (or two-division) light-receiving surface light-receiving element 12. . The divided photoelectric conversion outputs of the light receiving regions 13a to 13d are respectively input to the signal differential amplifier circuit 14 and amplified, and the respective axial output differences ΔE _x , ΔE _y , and ΔE _z are detected. All of these output differences are input to the calculation device 18 and calculated. The controller 16 calculates the shake of the laser light spot on the light receiving surface of the light receiving element 12 from the output difference of the arithmetic device 18, and further obtains the displacement of the piezoelectric element 1 from the shake in each axial direction.

This relationship is measured in advance and the controller 1
By formulating and converting into 6, the fine movement coordinates when an external force of arbitrary magnitude acts are ΔE _x , ΔE _y , ΔE.
_It can be calculated immediately and accurately from the measured value of _z .

The fine movement mechanism of FIG. 6 can be used as a fine movement device of a scanning probe microscope, especially a scanning tunneling microscope (STM). A probe or a sample table is fixedly provided on the lower surface of the lower end surface 3 of the piezoelectric element 1, and the X, Y, and Z axis coordinate values detected as described above are fed back to the fine movement control unit, and a deviation from a predetermined coordinate value is detected. The fine movement value of the piezoelectric element 1 can be controlled so as to become zero.

Although not described in the above embodiment, if a cantilever having one end fixed as a flexible system is used instead of the piezoelectric element 1 and the outer spherical mirror is installed on the back side of the probe, an atomic force microscope (AFM) is used. As the above), the fine motion detection system of the present invention can be used. Further, as the above-mentioned embodiment, the case where the piezoelectric strain is described as the external force is described, but it is obvious that the present invention also includes a case where other force such as atomic force or magnetic force acts on the flexible system in addition to this. Is.

[0076]

As described above, according to the present invention, the sensitivity of the fine motion detection of the scanning probe microscope (SPM) can be increased more than ever before, and the fine motion coordinates in the X, Y, and Z axis directions can be detected with high accuracy. It can be measured and controlled. Further, the fine movement detection system can be made smaller and simpler than before, and the loss of the detection light in the measurement system is small. Therefore, the present invention provides a fine movement mechanism,
In particular, it can contribute to improving the characteristics of the SPM fine movement device.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main component of a fine movement mechanism according to an embodiment.

FIG. 2 is a diagram showing a fine movement operation of the piezoelectric element 1 of FIGS.

FIG. 3 is a diagram showing a light receiving region of the four-division light receiving surface type light receiving element of FIGS. 1 and 6;

FIG. 4 is a top view showing fine movement positions of the outer spherical mirror of FIGS. 1 and 6;

5 is a diagram for explaining a shift of a reflection angle due to fine movement of the outer spherical mirror of FIGS. 1 and 6. FIG.

FIG. 6 is a perspective view showing the main components of a fine movement mechanism according to another embodiment.

FIG. 7 is a block diagram showing a configuration of a minute displacement measuring circuit by the fine movement mechanism of FIGS. 1 and 6.

FIG. 8 is a diagram showing an application example (using 3 outer spherical mirrors) of the optical lever method according to another embodiment.

FIG. 9 is a diagram showing an output characteristic of a four-division light receiving surface type light receiving element 12 through an amplifier.

FIG. 10 is an example showing input / output linearity of a light receiving element.

11 is a diagram showing measurement data obtained through an amplifier for minute displacement using the apparatus of FIG.

FIG. 12 is a diagram showing an application example of an optical lever method according to another embodiment.

[Explanation of symbols]

1 the piezoelectric element 2 the upper end surface 3 the lower end face 4 inner circumference electrode (ground electrode) 5x _1, 5x ₂ X-axis direction displacement electrode 5y _1, 5y ₂ Y-axis direction displacement electrode 5z Z axis direction displacement electrode 6 bottom 7 projections Part 10 Outer spherical mirror 11 Focused beam light source 11xy Focused beam source for XY plane displacement measurement 11zx Z-X plane displacement measurement focused beam source 12 4-division light receiving surface type light receiving element 12xy XY plane displacement measurement 4-division light reception Surface type light receiving element 12zx Z-X four-sided light receiving surface type light receiving element for displacement measurement 13a, 13b, 13c, 13d Light receiving area 14 Signal differential amplifier circuit 15 Laser oscillation circuit 16 Controller 17 Piezoelectric element drive circuit 18 Arithmetic device

Claims (11)

[Claims] 1. A flexible system having a fixed end fixed to an outer wall and a moving end finely moved by the action of an external force, a spherical mirror fixed to the moving end of the flexible system, and a spherical mirror at one point. A focused beam light source for irradiating a focused beam light and a single light receiving surface type or a multi-divided light receiving surface type light receiving element for receiving the reflected light thereof, wherein the focused beam light source and the light receiving element are disposed at predetermined positions on the outer wall at predetermined intervals. An optical detection system installed at a position, and means for calculating the movement displacement of the flexible system from a detection signal from a single light-receiving surface of the light-receiving element of the optical detection system or a detection signal between multi-divided light-receiving surfaces, Fine movement mechanism consisting of. 2. A flexible system having a fixed end fixed to the outer wall and a moving end finely moved by the action of an external force, a spherical mirror fixed to the moving end of the flexible system, and a spherical mirror different from each other. A plurality of focused beam light sources for irradiating the focused beam light from a direction, and receiving the reflected light thereof,
A plurality of light receiving elements paired with the focused beam light source, and a plurality of pairs of the focused beam light source and the light receiving elements, which are paired with each other, are installed at predetermined positions different from each other on the outer wall at predetermined intervals. And a means for calculating the displacement of the flexible system from the detection signals of the light receiving elements of the plurality of pairs of optical detection systems. 3. A flexible system having a fixed end fixed to the outer wall and a moving end finely moved by the action of an external force, a spherical mirror fixed to the moving end of the flexible system, and a spherical mirror different from each other. A plurality of focused beam light sources for irradiating the focused beam light from a direction, and receiving the reflected light thereof,
A plurality of multi-segmented light receiving surface type light receiving elements paired with a focused beam light source, and the plurality of focused beam light source and multi segmented light receiving surface type light receiving elements which are paired with each other are provided at predetermined positions different from each other on the outer wall. A plurality of pairs of optical detection systems that are installed at intervals and a plurality of pairs of optical detection systems, which are independent of each other, are obtained by removing the interference component from the movement displacement of the above flexible system from the detection signals of the multi-divided light receiving surface type light receiving element. A fine movement mechanism comprising means for calculating a value and. 4. A flexible system having a fixed end fixed to the outer wall and a moving end finely moving in a maximum of three axial directions by the action of an external force, and a spherical mirror fixed to the moving end of the flexible system. From the first focused beam light source and the spherical surface, which are fixed at predetermined intervals at the outer wall position where displacement along one plane of the three axes of the moving end can be detected and which send the focused beam light to the spherical mirror A four-division light receiving surface type light receiving element for receiving this reflected light, and a spherical mirror fixed at a predetermined interval at an outer wall position capable of detecting a displacement along a plane perpendicular to the one plane at the moving end. A second focused beam light source for sending the focused beam light to the four split light receiving surface type light receiving element for receiving the reflected light from the spherical surface, and a light receiving surface of the first four split light receiving surface type light receiving element
The displacement of the moving end is detected as an output change in each light receiving area, and the displacement of the moving end parallel to the light receiving surface of the second four-division light receiving surface type light receiving element is detected as an output change in each light receiving area, A fine movement mechanism comprising means for calculating the triaxial movement displacement of the flexible system from these detection signals as mutually independent values with interference components removed. 5. The movable end is X, Y, Z with respect to the fixed end.
A piezoelectric flexible system displaceable in three axial directions (X and Y are coordinate axes along the plane of the moving end and Z is a coordinate axis perpendicular to this plane), and a spherical mirror fixed to the moving end of the flexible system. And a first focused beam light source for transmitting focused beam light to a spherical mirror, which is fixedly installed at a predetermined interval at an outer wall position capable of detecting displacement along one plane of the three axes of the moving end, and a spherical surface. A four-division light-receiving surface type light-receiving element that receives this reflected light from, and a spherical surface that is fixed at a predetermined interval at the outer wall position where the displacement along the plane perpendicular to the one plane at the moving end can be detected. A second focused beam light source for sending the focused beam light to the mirror and a four-division light receiving surface type light receiving element for receiving the reflected light from the spherical surface, and a light receiving surface of the first four division light receiving surface type light receiving element,
The displacement of the moving end is detected as an output change in each light receiving area, and the displacement of the moving end parallel to the light receiving surface of the second four-division light receiving surface type light receiving element is detected as an output change in each light receiving area, A fine movement mechanism comprising means for calculating the triaxial movement displacement of the flexible system from these detection signals as mutually independent values with interference components removed. 6. The fine movement mechanism according to any one of claims 4 to 5, wherein the means for calculating is: Fine movement mechanism. 7. The fine movement mechanism according to claim 1, wherein the focused beam light source is a laser light source, and the spherical mirror has a spherical shape only at a portion where the focused beam light is incident. 8. The focused beam light source is a laser light source, and in place of the spherical mirror, a mirror having at least a portion on which the focused beam light is incident has an arbitrary curved surface is used.
7. The fine movement mechanism according to any one of to 6. 9. The scanning probe microscope according to claim 1, wherein a mechanism for supporting the fine motion probe is provided.
A scanning probe microscope in which two fixed mechanisms are used, and the fixed end for fixing the flexible system, the focused beam light source, and the light receiving element is part of the fixed portion of the microscope. 10. A fixed end of the movable end is X, Y, Z.
A piezoelectric flexible system displaceable in three axial directions (X and Y are coordinate axes along the plane of the moving end and Z is a coordinate axis perpendicular to this plane), and a spherical mirror fixed to the moving end of the flexible system. And a first focused beam light source for transmitting focused beam light to a spherical mirror, which is fixedly installed at a predetermined interval at an outer wall position capable of detecting displacement along one plane of the three axes of the moving end, and a spherical surface. A four-division light-receiving surface type light-receiving element that receives this reflected light from, and a spherical surface that is fixed at a predetermined interval at the outer wall position where the displacement along the plane perpendicular to the one plane at the moving end can be detected. A second focused beam light source for sending the focused beam light to the mirror and a four-division light receiving surface type light receiving element for receiving the reflected light from the spherical surface, and at least any one of X, Y and Z is provided in the piezoelectric scanner. A voltage is applied to give a displacement in the axial direction, Caused displacement in end passes, in this displacement, parallel to the light receiving surface of the first quartered light-receiving surface form the light receiving element,
The displacement of the moving end is detected as an output change in each light receiving area, and the displacement of the moving end parallel to the light receiving surface of the second four-division light receiving surface type light receiving element is detected as an output change in each light receiving area, A method for detecting a small displacement of a piezoelectric scanner, which calculates the three-axis movement displacement of the flexible system as independent values from which interference components are removed from these detection signals. 11. The method for detecting a minute displacement according to claim 10, wherein the calculation is: Small displacement detection method.