JPH0954101A - Scanning near-field optical microscope - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To obtain only shape information of a sample and optical information of a separated sample. This prevents a situation where the SN ratio is lowered and the sample cannot be measured with light having a desired wavelength. SOLUTION: The cantilever 1 bends in response to an atomic force acting between a probe 2 and a sample surface. The amount of deflection is converted into a resistance value by the PZT film 12 formed on the cantilever 1, and a signal corresponding to this is output from the detection unit 22. The control unit 23 and the driving device 21 move the cantilever 1 in the Z direction so that the amount of bending becomes constant, while moving the cantilever 1 in the X and Y directions so that the probe 2 scans the sample surface. To be The light detection unit 30 detects the evanescent wave reflected on the sample surface. Processing unit 3
Reference numeral 1 captures each control signal from the control unit 23 and the detection signal of the photodetection unit 30 to obtain both optical information and shape information of the sample 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning near field optical microscope.

[0002]

2. Description of the Related Art In recent years, non-contact and non-destructive high-resolution microscopes have been demanded in a wide range of fields such as biology, semiconductor device development, and surface analysis. Conventionally used optical microscopes are excellent in that they are non-contact and non-destructive,
On the principle of using an imaging optical system, the field of application has been limited due to the limited resolution due to the diffraction limit.

In order to solve these problems, scanning electron microscopes, transmission electron microscopes, scanning tunnel microscopes, scanning near-field optical microscopes (or optical near-field scanning microscopes, photon scanning tunnel microscopes, etc.) are used. Although developed, a scanning near-field optical microscope is the only means for obtaining the optical properties of a sample with high resolution.

As this type of scanning near-field optical microscope, the one disclosed in Japanese Patent Laid-Open No. 59-121310 is known. The basic principle of this scanning near-field optical microscope is to scan the surface of the sample with an aperture smaller than the wavelength of the irradiation light emitted from the light source to irradiate the sample, and measure the surface shape and the optical properties of the surface. Since the aperture is scanned from the sample at a distance shorter than the aperture diameter, it is called a scanning near-field optical microscope.

According to the theory of waves, the resolution of an ordinary optical microscope is limited to about λ / 2, so that it is limited to 200 to 300 nm in the visible light region. However, when light is guided to a minute aperture smaller than the wavelength as described above, a free space cannot be spread like ordinary light, but there exists an optical field that exudes near the aperture. This optical electric field is called an annihilation wave (evanescent wave), and it enables high-resolution optical measurement by irradiating the sample surface.

Further, when the irradiation light is incident from the back surface of the sample so that the total reflection condition is satisfied on the sample surface, an evanescent wave is generated on the sample surface. Since the evanescent wave decreases exponentially with the distance from the sample surface,
High-resolution optical measurement can also be performed by detecting the evanescent wave with a probe that scans the sample surface in a non-contact manner.

As described above, by utilizing the scanning near-field optical microscope, it is possible to measure the shape and optical information of the sample surface with high resolution. However, the intensity of the evanescent wave is greatly influenced not only by the distance from the sample surface to the probe, but also by local optical properties (reflectance, refractive index, absorbance, etc.) on the sample surface. Therefore, the shape and optical properties of the sample surface can be measured at the same time, but the two are not separated. Therefore, when it is desired to obtain only optical information, it is necessary to use some means to separate the two.

Therefore, it has been considered to combine the function of an atomic force microscope (AFM) with a scanning near field microscope. The atomic force microscope is a scanning probe microscope in which a cantilever having a probe at its tip is brought close to the sample surface and the deflection of the cantilever due to the atomic force acting between the probe and the sample surface is measured. As a method for detecting the amount of deflection of the cantilever, an optical lever method, an optical interference method, etc. are generally used, and the cantilever is irradiated with light for detecting deflection. As a scanning near-field optical microscope having such an atomic force microscope function, for example, a paper (NF van Hust, MH
P. Moers, OFJ Noordman, T. Fauldner, FB Segeri
nk, KO van der Werf, BG de Groothand B. Bolge
r, Operating of a scanning near field optical micr
oscope inreflection in combination with a scanning
force microscope, SPIE Vol.1639 Scanning Probe Mi
croscopies, pp.36-43 (1992)).

According to the scanning near-field optical microscope having the function of such an atomic force microscope, an atomic force acts between the probe and the sample surface, and the cantilever bends in response to this force. The cantilever is irradiated with light separately from the light for generating the evanescent wave to detect the amount of bending of the cantilever, and based on the detection signal, the cantilever is placed perpendicular to the sample surface so that the amount of bending of the cantilever becomes constant. While moving in the direction, the cantilever is moved so that the probe scans the sample surface in the direction parallel to the sample surface. Therefore, the probe scans the sample surface in the direction of a plane substantially parallel to the sample surface while keeping the distance between the probe and the sample constant by following the unevenness of the sample surface.
Therefore, only the optical information is included in the evanescent wave detection signal, and only the optical information of the sample can be obtained separately from the shape information.

[0010]

However, in the conventional scanning type near-field optical microscope having the function of the atomic force microscope, the optical lever method, the optical interferometry method or the like is adopted to detect the deflection of the cantilever, and the evanescent method is used. Since the light is applied to the cantilever separately from the light for generating the wave, the S / N ratio may decrease, and it may not be possible to measure the sample with light of a desired wavelength. It became clear by the research of the person.

This point will be described in detail below with reference to FIG.

FIG. 5 is a diagram showing the characteristics of the detected light by the evanescent wave generated by generating the evanescent wave by the white light and reflected at a certain point on the sample surface. In FIG. 5, the horizontal axis indicates the wavelength and the vertical axis indicates the intensity of the detection light. FIG.
FIG. 5A shows an ideal characteristic of the detection light reflecting only the optical information on the sample surface, FIG. 5B shows the characteristic of the actual detection light, and FIG. 5C shows the cantilever deflection. The characteristics of the detection light transmitted through the optical filter in order to remove the influence of light for Note that the light emitted to the cantilever for detecting the bending of the cantilever (hereinafter, referred to as “bending detection light”) is usually monochromatic light, and therefore the wavelength of the bending detection light is set to λ ₀ in FIG. Shows.

In the conventional scanning near-field optical microscope, since the deflection detection light is irradiated, a part of the deflection detection light becomes stray light and is detected by the evanescent wave detection system, and the deflection detection light shown in FIG. As shown in b), the detected light includes not only the evanescent wave but also the stray light (FIG. 5).
(See also (a)). In FIG. 5B, A indicates a stray light component. Therefore, when the intensity of the detected light is detected as white light (normally, it is detected as white light), the integrated value of the curve in FIG. 5 is the intensity, but the stray light component A
Is deviated from the original detected light intensity, and that amount becomes noise. And the deflection detection light is several meters.
Since it is much larger than W and the evanescent wave (1 pW to 1 mW), the noise due to the stray light is large and the SN ratio is considerably lowered.

Therefore, the detection light may be transmitted through an optical filter that cuts the component near the wavelength λ ₀ of the deflection detection light. In this case, the detection light transmitted through the optical filter is as shown in FIG. 5C, and the stray light component A in FIG. 5B is cut. However, in this case, when detecting the intensity of the detection light transmitted through the optical filter as white light, the component around the wavelength λ ₀ is cut off, so that the curve in FIG. The intensity, which is the integral value of, decreases. Further, since the optical filter actually has a characteristic deviated from the ideal filtering characteristic, the intensities of other wavelength components also inevitably decrease, which also shows in FIG.
The intensity, which is the integral value of the curve in (b), decreases. In this way, the optical filter reduces the intensity of the detection light, so that the SN ratio is reduced.

By the way, depending on the sample (eg, photosensitive material), it is required to measure the optical property of the sample at a predetermined wavelength. In this case, the intensity of the detection light is detected as monochromatic light by dispersing the detection light with a spectroscope or the like. In this case,
As can be seen from FIGS. 5B and 5C, the wavelength λ ₀
In the vicinity, it becomes impossible to measure the optical properties of the sample. Moreover, when an optical filter is used,
As indicated by reference characters B and C in FIG. 5C, the characteristics of the optical filter (deviation from the ideal filtering characteristics) are reflected, and the strength of the detection light transmitted through the optical filter is reflected for the strength of a certain wavelength. Is largely deviated from the original detection light intensity (FIG. 5A), and the SN ratio is greatly reduced for the wavelength.

Further, depending on the sample, optical information may be measured by irradiation with light having a predetermined wavelength. For example, when measuring the optical information of a photosensitive material that has the property of being exposed to blue light to change to red when exposed to red light and returning to the original color by being irradiated with red light, an evanescent wave due to blue light is generated to generate an evanescent wave. Observe the changes in the photosensitive material. At this time, if the bending detection light is red light, stray light of the bending detection light irradiates the photosensitive material to restore the original color, and desired measurement cannot be performed.

The present invention has been made in view of the above circumstances, and it is possible to obtain only the shape information of the sample and the optical information of the separated sample, and further, to reduce the SN ratio and the sample by the light of the desired wavelength. It is an object of the present invention to provide a scanning near-field optical microscope capable of preventing a situation in which the above measurement cannot be performed.

[0018]

In order to solve the above-mentioned problems, a scanning near-field optical microscope according to the first aspect of the present invention comprises a cantilever having a probe at its tip and an evanescent wave from the tip of the probe. Irradiation means for irradiating the probe with light so as to generate, a light detection means for detecting an evanescent wave transmitted through the sample or reflected on the sample surface, and the probe in a direction substantially perpendicular to the sample surface. First moving means for moving the cantilever relative to the sample, second moving means for moving the cantilever relative to the sample in a direction substantially parallel to the sample surface, and the sample surface And a means for obtaining information about a detection signal from the photodetection means according to a relative position of the cantilever with respect to the sample surface in a direction of a plane substantially parallel to the scanning near-field optical microscope. A detection means for outputting a signal according to the voltage generated by the piezoelectric film or the resistance value of the film by forming a piezoelectric film or a film whose resistance value changes according to the applied pressure on the cantilever; While controlling the first moving means so that the deflection of the cantilever becomes constant based on a signal from the means, the probe scans the sample surface in a direction substantially parallel to the sample surface. And a control means for controlling the second moving means.

The scanning near-field optical microscope according to the second aspect of the present invention irradiates light from the cantilever having a probe at the tip and the back surface of the sample under total reflection conditions so that an evanescent wave is generated on the sample surface. Irradiation means, light detection means for detecting an evanescent wave captured by the probe or reflected at the tip of the probe, and the probe is moved relative to the sample in a direction substantially perpendicular to the sample surface. First to let
Moving means for moving the cantilever relative to the sample in a direction substantially parallel to the surface of the sample, and a second moving means for moving the cantilever in a direction substantially parallel to the surface of the sample. In a scanning near-field optical microscope provided with a means for obtaining information on a detection signal from the photodetection means according to a relative position with respect to the sample surface, the resistance value changes according to the piezoelectric film or the applied pressure. A film that is formed on the cantilever and outputs a signal according to the voltage generated by the piezoelectric film or the resistance value of the film, and the deflection of the cantilever becomes constant based on the signal from the detection device. Control means for controlling the second moving means such that the probe scans the sample surface in the direction of a plane substantially parallel to the sample surface while controlling the first moving means as described above. , In which further comprising a.

A scanning near-field optical microscope according to a third aspect of the present invention is the scanning near-field optical microscope according to the first or second aspect, wherein the cantilever of the cantilever in a direction substantially parallel to the sample surface is provided. It further comprises means for obtaining information on the relative position of the cantilever with respect to the sample surface in a direction substantially perpendicular to the sample surface, according to the relative position with respect to the sample surface.

According to the first to third aspects, an atomic force acts between the probe and the sample surface, and the cantilever bends in response to this force. The amount of bending of the cantilever is converted into a voltage or a resistance value by the piezoelectric film or the film, and a signal corresponding to this is output from the detection means. The first and second moving means and the control means move the cantilever in a direction substantially perpendicular to the sample surface so that the deflection amount of the cantilever becomes constant based on the signal from the detecting means, and the sample surface The cantilever is moved so that the probe scans the sample surface in a direction substantially parallel to. Therefore, the probe scans the sample surface in the direction of a plane substantially parallel to the sample surface while keeping the distance between the probe and the sample constant by following the unevenness of the sample surface. Therefore, the detection signal from the light detection means contains only optical information,
Only the optical information of the sample can be obtained separately from the shape information.

According to the first to third aspects, the deflection amount of the cantilever is detected by the piezoelectric film or the film formed on the cantilever and the detecting means, and the conventional scanning near-field optical microscope. Unlike the above, since the bending detection light is not emitted, the influence of stray light due to the bending detection light is eliminated and it is not necessary to use an optical filter.
Therefore, it is possible to prevent a situation in which the SN ratio is reduced and the sample cannot be measured with light having a desired wavelength.

According to the first and second aspects, since the movement control of the probe similar to the so-called contact mode in the atomic force microscope can be realized, the relative position can be controlled as in the third aspect. By obtaining the information regarding the above, it is possible to obtain the shape data of the unevenness of the sample surface, which is more preferable for observing the sample.

[0024]

DETAILED DESCRIPTION OF THE INVENTION A scanning near-field optical microscope according to the present invention will be described below with reference to the drawings.

(Embodiment 1) First, a scanning type near-field optical microscope according to a first embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

FIG. 1 is a schematic configuration diagram schematically showing the scanning near-field optical microscope according to this embodiment. Further, FIG. 2 is a schematic sectional view showing the cantilever 1.

The scanning near-field optical microscope according to this embodiment includes a cantilever 1 having a probe 2 at its tip, as shown in FIG. In the present embodiment, the cantilever 1 has a plate-shaped beam portion (lever portion) 3 and a support 4 that supports one end of the beam portion 3 as shown in FIG. The probe 2 is provided in a projecting manner on the tip side region of the lower surface. The beam portion 3 is composed of a silicon nitride film 5 extending from the portion of the support body 4. The support 4 is composed of a silicon nitride film 5, silicon oxide films 6 and 7, a silicon substrate 8 and a silicon nitride film 9. The probe 2 includes a hollow weight 5a having a bottom surface (upper surface) made of silicon nitride and continuously protruding from the silicon nitride film 5 and having an opening, and the weight 5a.
And a metal coating (light-shielding film) 10 formed on the periphery thereof. A minute opening 11 smaller than the wavelength of incident light is formed at the apex of the weight 5a, and the metal coating 10 is formed so as not to collapse the minute opening 11. Such a cantilever 1 can be manufactured using semiconductor manufacturing technology.

The structure of the cantilever 1 is not limited to the structure described above, and the cantilever disclosed in the above-mentioned paper can be used, for example. This cantilever is made of silicon nitride having a pyramid type probe. This probe has no physical aperture and is solid rather than hollow. Moreover, the probe is not coated with metal. In this cantilever, for example, when light for generating an evanescent wave is irradiated from the back surface near the tip of the probe, since the refractive index of silicon nitride (transparent material) is as high as 2.0, the irradiated light is a pyramidal type. Although it is totally reflected on the side surface of the probe, the condition of total reflection is not satisfied at the tip of the probe, so
A small amount of light passes through the probe and an evanescent wave is generated at the tip of the probe.

The PZT film 1 is formed on the cantilever 1.
2 is formed as a film whose resistance value changes according to the applied pressure. That is, in this embodiment, as shown in FIG.
As shown in, the PZT film 12 is formed on the beam portion 3 of the cantilever 1.
Are formed by sputtering or the like, and electrodes 13 and 14 are formed on both sides of the PZT film 12. The electrode 13 between the PZT film 12 and the silicon nitride film 5 extends to the support 4. A film whose resistance value changes according to the applied pressure is P
The film is not limited to the ZT film, and various other films can be used.

Referring again to FIG. 1, the scanning near-field optical microscope according to the present embodiment has a Z direction perpendicular to the surface of the sample 20 and a direction parallel to the surface of the sample 20 and orthogonal to each other. The cantilever drive device 21 that independently moves the cantilever 1 in the X and Y directions, the detection unit 22 that outputs a signal according to the resistance value of the PZT film 12 formed on the cantilever 1, and the detection unit 22 Of the cantilever 1 (that is, the beam 3
Cantilever drive device 21 so that the
Control unit 2 that controls the drive of the cantilever drive device 21 in the X and Y directions so that the probe 2 scans the surface of the sample 20 in the X and Y directions while controlling the drive in the Z direction.
3 and 3 are provided. In FIG. 1, 24 is a sample table on which the sample 20 is mounted, and 25 is a vibration isolation table for removing the influence of external vibration.

In the present embodiment, only the cantilever 1 side is moved by the cantilever drive device 21, but either the cantilever 1 side or the sample 20 side may be actually moved. For example, the cantilever 1 side may be moved only in the Z direction and the sample 20 side may be moved in the X and Y directions.

As for the cantilever drive device 21, a tripot type scanner provided with a piezoelectric body that can be independently moved in the X direction, the Y direction and the Z direction is used, or a tube type scanner is also used. It doesn't matter which one.

By the way, in this tube type scanner, a piezoelectric body having a cylindrical shape is provided with electrodes on either the inner surface or the outer surface, and the other surface is divided into a plurality of parts. It has the structure provided with the electrode.
Then, this tube-type scanner applies an arbitrary voltage between an electrode provided on one surface and a divided electrode provided on the other surface, whereby the cantilever 1
Can be moved in any X, Y and Z directions.

Further, as the detection unit 22, for example,
You can use the Wheatstone bridge.

Further, the scanning near-field optical microscope according to this embodiment includes an evanescent wave generating light source (a laser light source in this embodiment) 26, a polarization beam splitter 27, a quarter wavelength plate 28, The condenser lens 29 and the photodetector 30 are provided. The evanescent wave generation light source 26 does not necessarily have to be a laser light source, and may emit incoherent light. Further, the light source 26 may emit monochromatic light or may emit white light.

The linearly polarized laser light emitted from the light source 26 passes through the polarization beam splitter 27 and is circularly polarized by the quarter wavelength plate 28. The condenser lens 29 condenses the light from the back surface (upper surface) of the probe 2 to the vicinity of the minute opening 11 of the probe 2. As a result, an evanescent wave is generated from the minute opening 11 of the probe 2. This evanescent wave is
The light is reflected on the surface of the sample 20, returns to the minute aperture 11, and again passes through the quarter-wave plate 28 via the condenser lens 29. 1
Since the plane of polarization of the light transmitted through the quarter wave plate 28 is orthogonal to the plane of polarization of the original laser light, the quarter wave plate 28
The return light that has passed through is reflected by the polarization beam splitter 27 and received by the photodetector 30.

As can be seen from the above description, in the present embodiment, the light source 26, the polarization beam splitter 27, 1 /
The four-wave plate 28 and the condenser lens 29 configure an irradiation unit that irradiates the probe 2 with light so that an evanescent wave is generated from the tip of the probe 2. Further, the photodetection section 30 constitutes a photodetection means for detecting the evanescent wave reflected on the sample surface. Note that, as the light detection unit 30, specifically, for example, a light detector such as a photodiode can be used. When measuring the optical property of the sample at a predetermined wavelength, in the photodetection section 30, for example, a spectroscope may be provided in front of the photodetector.

Further, as shown in FIG. 1, the scanning near-field optical microscope according to this embodiment includes a processing section 31 and a display section 32. The control signal in the Z direction given from the control unit 23 to the cantilever drive device 21 is the probe 2
Indicates the relative position in the Z direction with respect to the sample surface. Further, the control signals in the X and Y directions given from the control unit 23 to the cantilever drive device 21 indicate the relative position of the probe 2 in the X and Y directions with respect to the sample surface. The processing unit 31 takes in each control signal from the control unit 23 and the detection signal of the light detection unit 30, and detects the detection signal of the light detection unit 30 according to the relative position of the probe 2 in the X direction and the Y direction with respect to the sample surface. Information about the level (that is, optical information of the sample 20) is obtained, and the probe 2 corresponding to the relative position of the probe 2 in the X direction and the Y direction with respect to the sample surface.
The information about the relative position of the Z direction with respect to the sample surface (that is, the shape information of the sample) is obtained. Then, these pieces of information are displayed as images on the display unit 32 such as a CRT.

According to the scanning near-field optical microscope of this embodiment, an atomic force acts between the probe 2 and the sample surface, and the cantilever 1 bends in response to this force. The deflection amount of the cantilever 1 is converted into a resistance value by the PZT film 12,
A signal corresponding to this is output from the detection unit 22. Then, the control unit 23 and the cantilever driving device 21 move the cantilever 1 in the Z direction so that the amount of bending of the cantilever 1 becomes constant based on the signal from the detection unit 22, while searching in the X direction and the Y direction. The cantilever 1 is moved so that the needle 2 scans the sample surface. Therefore, the probe 2 and the sample 20 follow the unevenness of the sample surface.
The probe 2 scans the sample surface in the direction of a plane substantially parallel to the sample surface while maintaining a constant distance between the sample surface and the sample surface. Therefore, only the optical information is included in the detection signal from the light detection unit 22, and only the optical information of the sample 20 can be obtained separately from the shape information.

According to the present embodiment, the amount of bending of the cantilever 1 is detected by the PZT film 12 formed on the cantilever 1 and the detecting portion 22, and the bending detection is different from the conventional scanning near-field optical microscope. Since the use light is not emitted, the influence of stray light due to the deflection detection light is eliminated and it is not necessary to use an optical filter. Therefore, the light detected by the light detection unit 22 becomes ideal as shown in FIG. 5A, for example, to prevent a decrease in the SN ratio and a situation in which the sample cannot be measured with light of a desired wavelength. be able to.

Further, in this embodiment, the shape information of the sample 20 is obtained by the processing unit 23, which is preferable for observing the sample 20. However, in the present invention, it is not always necessary to obtain the shape information of the sample.

(Second Embodiment) Next, a scanning type near-field optical microscope according to a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

FIG. 3 is a schematic configuration diagram schematically showing the scanning near-field optical microscope according to this embodiment. 3, constituent elements that are the same as or correspond to the constituent elements in FIG. 1 are assigned the same reference numerals, and descriptions thereof will be omitted.

The scanning near-field optical microscope according to this embodiment differs from the scanning near-field optical microscope according to the first embodiment in that the polarization beam splitter 2 in FIG.
7, the quarter wave plate 28 and the condenser lens 29 are deleted,
The only difference is that the photodetection section 30 is arranged on the back side of the sample 20 so that the photodetection section 30 detects the evanescent wave transmitted through the sample 20. That is, in the present embodiment, the light source 30 constitutes an irradiation unit that irradiates the probe 2 with light so that an evanescent wave is generated from the tip of the probe 2, and the photodetection unit 30 transmits the evanescent wave through the sample. It constitutes a light detecting means for detecting.

Whereas the scanning near-field optical microscope according to the first embodiment is a so-called reflection type for detecting the evanescent wave reflected on the sample surface, the scanning near-field optical microscope according to the present embodiment. Is a so-called transmission type that detects an evanescent wave that has passed through the sample.

According to the present embodiment, as in the case of the first embodiment, it is possible to prevent a decrease in the SN ratio and a situation in which the sample cannot be measured with light of a desired wavelength.

(Third Embodiment) Next, a scanning type near-field optical microscope according to a third embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

FIG. 4 is a schematic configuration diagram schematically showing the scanning near-field optical microscope according to this embodiment. 4, the same components as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. Note that, also in the present embodiment, the cantilever 1 as disclosed in the above-mentioned paper can be adopted as the cantilever 1.

The scanning near-field optical microscope according to this embodiment differs from the scanning near-field optical microscope according to the first embodiment in that the polarization beam splitter 2 in FIG.
7, the quarter wave plate 28 and the condenser lens 29 are deleted,
A prism 40 having a triangular prism shape is provided as a sample table instead of the sample table 24, and light from the light source 26 is incident from the back surface of the sample 20 through the prism 40 so that the total reflection condition is satisfied on the surface of the sample 20. The only difference is that the light source 26 is arranged on the side of the prism 40 and the photodetector 30 is arranged above the probe 2.

In the present embodiment, the light from the light source 26 is incident from the back surface of the sample 20 through the prism 40 so as to satisfy the condition of total reflection on the surface of the sample 20, whereby the evanescent wave is emitted near the surface of the sample 20. Occurs. Probe 2
The evanescent wave near the tip of the probe 2 enters the probe 2 from the tip of the probe 2 (that is, is captured by the probe 2), becomes propagating light, passes through the probe 2, and is detected by the photodetector 30. .

As can be seen from the above description, in the present embodiment, the light source 26 and the prism 40 constitute the irradiation means for irradiating light from the back surface of the sample under the condition of total reflection so that the evanescent wave is generated on the surface of the sample. The light detection unit 30 constitutes light detection means for detecting the evanescent wave captured by the probe 2. The shape of the prism 40 is not limited to the triangular prism.

According to the present embodiment, as in the first embodiment, it is possible to prevent the situation where the SN ratio is lowered and the sample cannot be measured with the light of the desired wavelength.

In the present embodiment, as described above, the photodetector 30 is arranged above the probe 2, and the photodetector 30 detects the evanescent wave captured by the probe 2. However, the light detection unit 30 may be arranged on the side of the probe 2 so that the light detection unit 30 detects the evanescent wave scattered (that is, reflected) at the tip of the probe 2.

Although the respective embodiments of the present invention have been described above, the present invention is not limited to these embodiments.

For example, in each of the above embodiments, the PZT film 12 is formed on the cantilever 1 as a film whose resistance value changes in accordance with the applied pressure, but instead of this, a piezoelectric film is formed on the cantilever 1. You may form. As the piezoelectric film, various kinds can be adopted, but PZT
Membranes can also be used. When a PZT film is formed as a piezoelectric film on the cantilever 1, the crystal axis direction of the PZT film and the like are determined so that the flexure of the cantilever 1 causes a voltage as large as possible between the electrodes 13 and 14. When the piezoelectric film is formed on the cantilever 1, the detection unit 22 may have the same configuration as a voltmeter, for example.

[0056]

As described above, according to the present invention,
It is possible to obtain only the shape information of the sample and the optical information of the separated sample, and it is possible to prevent a situation in which the SN ratio is lowered and the sample cannot be measured with light of a desired wavelength.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram schematically showing a scanning near-field optical microscope according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a cantilever.

FIG. 3 is a schematic configuration diagram schematically showing a scanning near-field optical microscope according to a second embodiment of the present invention.

FIG. 4 is a schematic configuration diagram schematically showing a scanning near-field optical microscope according to a third embodiment of the present invention.

FIG. 5 is a diagram showing characteristics of detection light.

[Explanation of symbols]

 1 cantilever 2 probe 12 PZT film 20 sample 21 cantilever drive device 22 detection unit 23 control unit 24 sample stage 26 light source for evanescent wave generation 27 polarized beam splitter 28 quarter wave plate 29 condenser lens 30 photodetection unit 31 processing unit 32 display 40 prism

Claims (3)

[Claims] 1. A cantilever having a probe at its tip,
An irradiation unit that irradiates the probe with light so that an evanescent wave is generated from the tip of the probe, a light detection unit that detects the evanescent wave that passes through the sample or is reflected by the sample surface, and substantially perpendicular to the sample surface. First moving means for moving the probe relative to the sample in any direction, and second moving means for moving the cantilever relative to the sample in a direction substantially parallel to the sample surface. Scanning means, including means for obtaining information about a detection signal from the photodetection means according to the relative position of the cantilever with respect to the sample surface in the direction of a plane substantially parallel to the sample surface. In a field optical microscope, a piezoelectric film or a film whose resistance value changes according to the applied pressure is formed on the cantilever, and a voltage generated by the piezoelectric film or a signal corresponding to the resistance value of the film Outputting detection means and the probe in a direction substantially parallel to the sample surface while controlling the first moving means so that the deflection of the cantilever becomes constant based on the signal from the detection means. A scanning near-field optical microscope, further comprising: a control unit that controls the second moving unit to scan the surface of the sample. 2. A cantilever having a probe at its tip,
Irradiation means for irradiating light from the sample back surface under total reflection conditions so that an evanescent wave is generated on the sample surface, and light detection means for detecting an evanescent wave captured by the probe or reflected at the tip of the probe, First moving means for moving the probe relatively to the sample in a direction substantially perpendicular to the sample surface, and the cantilever relative to the sample in a direction substantially parallel to the sample surface. Second moving means for moving the cantilever, and means for obtaining information regarding a detection signal from the light detecting means in accordance with the relative position of the cantilever with respect to the sample surface in the direction of a plane substantially parallel to the sample surface. In a scanning near-field optical microscope provided with, a piezoelectric film or a film whose resistance value changes according to applied pressure is formed on the cantilever, and a voltage generated by the piezoelectric film or Detecting means for outputting a signal according to the resistance value of the recording film; and controlling the first moving means so that the deflection of the cantilever becomes constant based on the signal from the detecting means, The scanning near-field optical microscope further comprising: a control unit that controls the second moving unit so that the probe scans the sample surface in the direction of a substantially parallel surface. 3. Information relating to the relative position of the cantilever with respect to the sample surface in a direction substantially perpendicular to the sample surface, according to the relative position of the cantilever with respect to the sample surface in the direction of a plane substantially parallel to the sample surface, The scanning near-field optical microscope according to claim 1 or 2, further comprising means for obtaining.