JPH06180228A - Surface observation apparatus - Google Patents

Abstract

PURPOSE:To obtain an apparatus wherein it can perform the transmitted illumination of a sample without lowering its measuring accuracy and it is suitable for the observation of a living thing by a method wherein an actuator is formed to be a hollow shape and an illumination system is arranged in its hollow part. CONSTITUTION:A probe 2 is arranged so as to face a sample 4, and a physical quantity such as an interatomic force or the like is made to act between both by bringing both close to each other or by bringing both into contact with each other. A hollow actuator 5 scans the face of the sample 4 three-dimensionally. At this time, the physical quantity is monitored on a display device 3, and the face shape of the sample 4 can be measured. An observation optical system 1 is constituted in such a way that it can observe the surface of the sample 4 optically and that it can align the probe 2 with a measuring position on the sample 4. A transparent member 7 is attached directly to the actuator 5, and the actuator 5 is bonded and fixed integrally to the base of an illumination device 6 for the transmitted illumination of the sample 4. As a result, the structure of the actuator is resistant to a vibration. In addition, since the transparent member 7 is held by the actuator 5, the member is not supported unilaterally from the viewpoint of its structure and it is resistant to a vibration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for observing the surface of a sample, such as an atomic force microscope (hereinafter abbreviated as AFM) or a magnetic force microscope, by bringing a probe close to the sample surface and observing the physical quantity received from the sample.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for observing a sample surface for optical observation, there is an invention described in Japanese Patent Laid-Open No. 3-71001, for example. The above invention uses the epi-illumination, which will be described below with reference to FIG.

Light emitted from the detector 54 is emitted from the half mirror 5.
5 and the lens 52, and is reflected by the cantilever 53. The reflected light returns along the same optical path to the detection unit 54. Through this series of operations, the detection unit 54 has a function of detecting the displacement of the cantilever 53, and detects the force acting between the cantilever 53 and the sample 50.

Since the detected force corresponds to the unevenness on the surface of the sample 50, the surface can be observed by displaying it. In addition, since it is necessary to specify the observation position in advance, the surface of the sample 50 and the cantilever 53 are measured by using an optical observation means.
Observe the position of.

In the conventional example, the illumination light emitted from the light source 58 is collimated by the lens 57 and reflected by the half mirror 56. The illumination light reflected by the half mirror 56 passes through the half mirror 55, enters the lens 52, and further illuminates the cantilever 53 and the sample 50. The illumination light reflected from the sample 50 is reflected by the lens 52 and the half mirror 5.
After passing through 5 and the half mirror 56, a lens 59 forms an image on the video camera 60 to observe the surface of the sample 50 and the cantilever 53.

[0006]

In the above prior art, when observing a transparent sample, since the optical observation illumination is epi-illumination, there is almost no reflected light from the sample and the observation site cannot be specified. Not suitable for organism observation.
Therefore, it is not possible to observe the unevenness of the transparent sample surface at the molecular level.

Therefore, in order to identify the observation site by the transmitted illumination irradiated from the lower side of the sample, simply incorporating the conventionally known transmitted illumination for microscopes is a sample consisting of an X / Y table on which a transparent sample is placed. The vibration of the holding part became a problem, and the measurement accuracy at the molecular level on the sample surface could not be obtained. In other words, when a transparent sample is placed and an X / Y table having a through hole so that it is illuminated from below, is slidably supported on a microscope base, the X / Y table and the base Although it forms a sliding surface with the guide surface of, the XY table is easy to move with respect to the guide surface of the base because it is slidable (the XY table can be moved by the external vibration transmitted through the base. However, the sample vibrates and the measurement accuracy at the molecular level was not obtained.

Therefore, the present invention was developed in view of the above problems in the prior art, and an object of the present invention is to provide a surface observation apparatus suitable for biological observation, capable of transmitting and illuminating a sample without lowering measurement accuracy. And

[0009]

SUMMARY OF THE INVENTION According to the present invention, a sample surface, a probe needle arranged to face the sample surface, and a probe surface which is brought into contact with or brought into contact with the sample surface to scan the sample surface. In a surface observation device having an actuator, a display device for displaying the surface shape of a sample from the displacement of the probe or the sample, and an observation optical system for optically observing the sample surface, the actuator has a hollow shape. An illumination system for illuminating the sample surface is formed in the hollow portion of the actuator, and a transparent member for mounting the sample is provided on the upper end portion of the actuator.

FIG. 1 is a conceptual diagram showing the present invention. As shown in the figure, in this device, the probe needle 2 is arranged so as to face the sample 4, and a physical quantity is exerted between them by approaching or contacting them. Specifically, this physical quantity acts as a tunnel current in the STM, an atomic force in the AFM, and a magnetic force in the magnetic force microscope.

The hollow actuator 5 three-dimensionally scans the surface of the sample 4. At this time, the surface shape of the sample 4 can be measured by monitoring the physical quantity with the display device 3. The observation optical system 1 is configured to optically observe the surface of the sample 4 and align the probe 2 with the measurement position on the sample 4. The lower end of the hollow actuator 5 is integrally bonded and fixed to the base of an illuminating device 6 which transmits and illuminates the sample 4 through the hollow portion of the hollow actuator 5, and a transparent member 7 is integrally provided on the upper end thereof. Has been.

[0012]

In the present invention, since the transparent member 7 is directly attached to the hollow actuator 5 and the hollow actuator 5 is integrally bonded and fixed to the base of the lighting device 6, the structure has a strong vibration resistance. Furthermore, since the transparent member 7 is held by the hollow actuator 5, the structure does not become a cantilever and is strong against vibration.

[0013]

Embodiment 1 FIGS. 2 to 6 show the present embodiment, FIG. 2 is a schematic configuration diagram, FIG. 3 is a perspective view of a cylindrical actuator, FIG. 4 is a cross-sectional view of the same, and FIGS. 5 and 6 show a cylindrical actuator. It is a perspective view which shows operation.

In FIG. 2, reference numeral 2 denotes a probe needle formed by mechanically polishing or electrolytically polishing the tip of a metal wire such as tungsten.
It is supported by the glass 15 at a position close to the surface of the sample 4. The glass 15 is held by the columns 25. The sample 4 is arranged so as to face the probe 2, and is supported by a cylindrical actuator 5 that holds a glass 16 at the upper end. The cylindrical actuator 5 is adhesively fixed to the column 25.

The cylindrical actuator 5 is a fine movement mechanism that can move in three orthogonal directions of X, Y and Z, and is formed as follows. First, the piezoelectric material is processed (sintered) into a hollow cylindrical shape. On its outer surface, four + x poles, which are the entire surface in the length direction,
Ag electrodes composed of −x pole, + y pole, and −y pole are equally spaced,
Moreover, the + x pole and the −x pole and the + y pole and the −y pole are provided so as to face each other. An Ag electrode (z pole) is provided on the entire inner peripheral surface.

On the other hand, the tunnel current detection controller 7 is composed of an I / V conversion circuit for applying a bias voltage to the sample 4 and converting the tunnel current between the probe 4 and the probe 2, and a log amp. The scanning signal generator 8 is composed of a high voltage amplifier, a sawtooth waveform generating circuit, and the like, and drives the cylindrical actuator 5. The shape display 9 is composed of a computer or the like for inputting the tunnel current value and the drive signal of the scanning signal generator 8.

The light source 13 is composed of a tungsten lamp or the like and is connected to a power source 14. The light emitted from the light source 13 is a cold filter 17 which is a commercially available infrared cut filter.
Through the lens 11, the mirror 12, the lens 10 and the glass 16 to illuminate the surface of the sample 4. Each of these parts is arranged by the Keller illumination method which is a general illumination method. The observation optical system 1 is a normal microscope optical system, and includes an objective lens and an eyepiece lens.

In the surface observing apparatus having the above structure, the scanning signal generator 8 finely moves the cylindrical actuator 5 to scan the sample surface 4. The fine movement of the cylindrical actuator 5 is X
In the axial direction, if the ± y pole and the inner z pole are made constant and +200 V is applied to the + x pole and −200 V is applied to the −x pole, the upper end thereof is in the −x pole direction due to the electrostriction effect (in FIG. 5, left side). Direction) for several tens of μm. Further, when -200 V is applied to the + x pole and +200 V is applied to the -x pole, it moves in the + x pole direction (reverse direction) (see FIG. 5). In the Y-axis direction, the ± x pole and the z-pole are kept constant, and ± 200 V is applied to the ± y pole to operate in the Y-axis direction. In the Z-axis direction, when a voltage is applied to the inner z-pole, it operates in the Z-axis direction (vertical direction) (see FIG. 6).

At this time, since the bias voltage is applied, a tunnel current flows between the probe 2 and the sample 4, and this value is taken into the shape display 9 and used as a drive signal for the scanning signal generator 8. By displaying the shape of the sample 4 in synchronism, the state of the surface of the sample 4 can be observed. At the same time, the light sources 13 and 11, 12, 10 are used for optical observation of the surface of the sample 4.
The sample 4 is transmitted and illuminated by the relay optical system, and the illumination light is focused on the observation optical system 1. The cold filter 17 is for preventing heat generation of the illumination system.

According to this embodiment, since the cylindrical actuator and the illumination lens are separated, the natural frequency of the cylindrical actuator is increased and the control characteristics are improved.

[0021]

Second Embodiment FIG. 7 is a schematic configuration diagram showing this embodiment.
In this example, the lens 10 and the glass 16 in Example 1 were eliminated, and a lens 18 was used instead. The lens 18 is held on the upper end of the cylindrical actuator 5 and supports the sample 4. Further, the lens 1 in the first embodiment
1, mirror 12, light source 13 and cold filter 17
Was abolished and replaced by a fiber light source 19 and an optical fiber 20 connected thereto. One end surface of the optical fiber 20 is arranged so that an image is formed on the entrance pupil of the observation optical system 1 by the lens 18. The fiber light source 19 consists of a tungsten lamp and simple optical parts, and
The other end surface of 0 is illuminated. Hereinafter, the configuration is the same as that of the first embodiment, the same reference numerals are given, and the description of the configuration is omitted.

An optical fiber 20 for guiding the light from the fiber light source 19 to the cylindrical actuator 5 is used. The lens 18 uniformly illuminates the surface of the sample 4 with the light from the optical fiber 20. Hereinafter, the operation is similar to that of the first embodiment, and the description of the operation is omitted.

According to this embodiment, since the glass plate contacting the sample and the illumination lens are made common, the structure is simplified. Furthermore, since the light from the light source is guided by the optical fiber, the pillar does not drift due to heat generated from the light source, and a stable surface observation image can be obtained.

[0024]

Third Embodiment FIG. 8 is a schematic configuration diagram showing the present embodiment.
In the present embodiment, the same components as those in the second embodiment are designated by the same reference numerals and the description thereof will be omitted. The probe needle 2 is arranged at the tip of the cantilever 24 whose one end is fixed to the column 25. As the cantilever 24, a sufficiently thin phosphor bronze foil piece or a foil manufactured by a semiconductor manufacturing technique is used.

A lens 27 is arranged so as to face the sample 4, a dichroic mirror 28 is placed between the cantilever 24 and the lens 26 of the observation optical system, and a detector 29 is provided at a position where the reflected light of the dichroic mirror 28 can be detected. To place. The dichroic mirror 28 is composed of a dichroic mirror manufactured to selectively reflect the light wavelength used in the detector 29.

As the detector 29, an optical sensor such as a triangulation method, an astigmatism method and a critical angle method is used. The detected signal is input to the control circuit 23. The control circuit 23 is composed of a general PID (proportional, integral, derivative) control circuit, and inputs it to the cylindrical actuator 5. The control amount of the control circuit 23 is input to the shape display 9. Transparent sample table 20
Holds the sample 4 by making it detachable from the cylindrical actuator 5.

The lens 27 is composed of a simple image forming optical system, and is held by the column 25. The lens 30 is the transparent sample table 2
It is arranged at the lower part of 0 and is held by the column 25. Filter 21
Is arranged at a position for blocking the light emitted from the fiber light source 19, and is configured to selectively block the wavelength reflected by the dichroic mirror 28, and is constituted by a commercially available optical filter or interference filter. Hereinafter, the configuration is the same as that of the second embodiment, and the description of the configuration is omitted.

Although the optical type is used as the detector in this embodiment, it can be easily realized by using the STM, the capacitance sensor or the like. Further, by configuring the transparent sample table 20 with the material of the filter 21, the filter 21 can be eliminated and the same effect can be realized.

The surface observing apparatus having the above-mentioned structure is provided with the detector 2 via the dichroic mirror 28 and the lens 27.
9 detects the amount of displacement of the cantilever 24. Then, the control circuit 23 controls the cylindrical actuator 5 so that the displacement becomes constant at a predetermined displacement amount. At this time, the scanning signal generator 8 scans the surface of the sample 4, and the surface shape is displayed on the shape display 9 based on the scanning signal and the control amount.

Filter 21 and dichroic mirror 2
8 is configured so that the light of the fiber light source 19 does not enter the detector 29, and selectively excludes the wavelengths emitted from the fiber light source 19 that can be reflected by the dichroic mirror 28. The sample 4 is illuminated with light other than the above, and the surface of the sample 4 is optically observed with the lenses 27 and 26.

According to this embodiment, since the disturbance due to the illumination light does not enter the detector, the surface shape can be measured with high accuracy while the illumination is on.

[0032]

As described above, according to the surface observation apparatus of the present invention, by integrating the cylindrical actuator and the transillumination system, it is possible to perform transillumination while preventing the rigidity of the apparatus from decreasing, and to achieve high accuracy. You can observe various surfaces.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing the present invention.

FIG. 2 is a schematic configuration diagram showing a first embodiment.

FIG. 3 is a perspective view of a cylindrical actuator according to the first embodiment.

FIG. 4 is a cross-sectional view of the cylindrical actuator according to the first embodiment.

FIG. 5 is a perspective view showing the operation of the cylindrical actuator in the first embodiment.

FIG. 6 is a perspective view showing the operation of the cylindrical actuator according to the first embodiment.

FIG. 7 is a schematic configuration diagram showing a second embodiment.

FIG. 8 is a schematic configuration diagram showing a third embodiment.

FIG. 9 is a schematic configuration diagram showing a conventional example.

[Explanation of symbols]

 1 Observation Optical System 2 Probe 3 Display Device 4 Sample 5 Hollow Actuator 6 Illumination Device 7 Transparent Member

Claims (1)

[Claims] 1. A sample surface, a probe needle arranged to face the sample surface, an actuator for scanning the sample surface by bringing the probe needle close to or in contact with the sample surface, and the probe needle or In a surface observation device having a display device for displaying the surface shape of a sample from the displacement amount of the sample and an observation optical system for optically observing the sample surface, the actuator is formed in a hollow shape, and a hollow portion of the actuator is formed. A surface observing apparatus comprising: an illumination system for illuminating the sample surface, and a transparent member for mounting the sample on an upper end of an actuator.