JPH06294638A - Surface profile measuring equipment - Google Patents

Abstract

PURPOSE:To obtain a surface profile measuring equipment in which the surface can be measured at high speed through a compact structure. CONSTITUTION:A diffraction grating 3 is provided on the plane opposite to the probe supporting plane 1 of a probe supporting member 2. A drive element 5 holding the probe supporting member 2 is connected with a controller 29. A displacement detector 8 projects light 6 and detects the position of the diffraction grating 7. The displacement detector 8 is connected with the controller 29.

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) and a magnetic 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 atomic force microscope, for example, there is an invention described in JP-A-3-296612. The above invention is shown in FIG. The probe support member 52 holds the probe 51. The probe support member 52 is displaced by bringing the sample 53 closer to the probe 51, and the displacement amount is detected by an optical lever type detector composed of a laser 54, an optical fiber 55, a lens 56, a mirror 57 and an optical sensor 58. .

In order to keep the distance between the sample 53 and the probe 51 at a constant position, the optical fiber 55 held by the drive element 59, the lens 56, the mirror 57, the optical sensor 58, the probe support member 52 and the probe. While controlling 51 in the Z direction,
At the same time, the surface of the sample 53 is scanned in the XY directions to observe the unevenness of the sample surface.

[0004]

However, in the above-mentioned prior art, in order to keep the distance between the sample and the probe at a constant position, an optical fiber, a lens, a mirror, an optical sensor,
Since the probe support member and the entire probe must be controlled by the drive element, the drive mass becomes large, the control characteristic becomes low, and the measurement speed becomes slow. Furthermore, the positional relationship among the lens, the optical sensor, and the probe support member is defined by the law of light reflection, so that the size cannot be reduced.

Therefore, the present invention was developed in view of the above-mentioned drawbacks of the prior art, and provides a surface shape measuring apparatus which is small in size and has a small driving portion mass and which can be controlled at high speed. The purpose is to

[0006]

The surface observing device of the present invention comprises a diffraction grating in one or more directions on the probe support member, and the light reflection angle is set by the direction and pitch of the grating. is there.

FIG. 1 is a conceptual diagram of the present invention, FIGS. 2 to 5 show a diffraction grating, FIG. 2 is a perspective view, and FIGS. 3 to 5 are schematic plan views showing examples of the shape of the diffraction grating. As shown in FIG. 1, in this device, the probe 1 is arranged so as to face the sample 4, and a physical amount acts between the two to displace the probe support member 2 by approaching or contacting them. This physical quantity is
AFM acts as an atomic force, and a magnetic force microscope acts as a magnetic force.

The driving element 5 is a probe 1 which moves the surface of the sample 4 two times.
Then, the displacement detector 8 detects the amount of displacement of the probe support member 2, and the controller 29 performs a control operation in the Z direction so as to make the displacement constant. At this time, the surface shape of the sample 4 can be measured by monitoring the control operation in the Z direction.

The probe support member 2 holding the probe 1 is
It is composed of an elastic member such as a leaf spring, and as shown in FIG. 2, the diffraction grating 3 is formed on the surface opposite to the surface on which the probe 1 is held. The displacement detector 8 has a function of projecting a laser beam and a function of detecting the position of the light diffracted by the diffraction grating.

The angle θ between the projected light 6 and the diffracted light 7 is P, where the incident angle of the laser light on the diffraction grating is 1, the reflection angle is θ, the wavelength of the laser light is λ, and the diffraction grating pitch is P.
It is represented by (sinI + sinθ) = mλ. m is the order of the m-th order diffracted light.

By changing the grating direction and the grating pitch of the diffraction grating 3 in this way, it is possible to emit diffracted light in any direction. The diffraction angle of the diffracted light 7 changes when the probe supporting member 2 changes, and the displacement detector 8 can detect this and know the displacement amount.

[0012]

First Embodiment FIG. 6 is a schematic configuration diagram showing this embodiment.
The support 11 holds the laser light source 16, the lens 22, the sensor 14, the sensor 15, the drive element 5, and the coarse movement mechanism 26. As shown in FIG. 2, the probe 1 is arranged at the tip of the probe supporting member 2 so as to face the sample 4, and the diffraction grating 23 is arranged at a position corresponding to the back surface of the probe 1. The probe support member 2 is held by the drive element 5. As the probe support member 2, a sufficiently thin phosphor bronze foil piece or a Si foil manufactured by a semiconductor manufacturing technique is used.

The laser light source 16 and the lens 22 are arranged at positions facing the diffraction grating 23. The sensors 14 and 15 are arranged according to the diffraction angle θ determined by the grating pitch of the diffraction grating 23 and the laser light source 16. The diffraction angle is
As an example, with respect to the laser light source 16 having a wavelength of 0.8 μm, the first-order diffracted light is generated in the direction of 23.6 degrees when the grating pitch is 2 μm. The sensors 14 and 15 are commercially available sensors such as a position sensor or a two-divided sensor.

The outputs of the sensor 14 and the sensor 15 are sent to an amplifier 17 and an amplifier 18, respectively, and an adder 19
And is processed by the control circuit 20 to be a Z direction control signal of the driving element 5. Further, the XY scanning signal generated by the output of the control circuit 20 and the driving element 5 is input to the monitor unit 21. The control circuit 20 is generally composed of a PID (proportional / integral / derivative) control circuit.

The drive element 5 is a fine movement mechanism composed of a piezoelectric element and a simple scanning signal generating circuit, and is configured to be operable in three orthogonal directions of XYZ, where the direction perpendicular to the paper surface is the Y direction. . The coarse movement mechanism 26 is composed of a stage or the like that operates in the XYZ directions.

In the apparatus having the above-described structure, the coarse movement mechanism 26 for roughly adjusting the positions of the probe 1 and the sample 4 is operated to bring the sample 4 close to the probe 1, thereby making the probe 1 and the sample 4 closer to each other. A force acts between the two, and the probe support member 2 is displaced. The light emitted from the laser light source 16 for detecting the displacement amount is condensed by the lens 22 and projected onto the diffraction grating 23.

The diffracted light obtained as a result is received by the sensor 14 and the sensor 15, and the change in angle due to the displacement of the probe support member 2 is detected as a change in position based on the principle of the optical lever detection method. The output from the sensors 14 and 15 is fed to the amplifier 1
The position signals are calculated by 7 and 18, and both signals are added by the adder 19. In order to control the displacement of the probe support member 2 due to the change in the unevenness of the surface of the sample 4 to be constant, the probe support member 2 is operated in the Z direction by the drive element 5.

At this time, the light on the sensors 14 and 15 is
According to the amount of movement by the drive element 5, the directions change in opposite directions,
The amount changed by adding the outputs of the both in the adder 19 cancels each other out, and the output of the adder 19 does not change. This serves to eliminate the displacement sensitivity of the probe support member 2 due to the control operation and to detect only the displacement change due to the unevenness of the sample 4.

The operation of the probe support member 2 in the Z direction is performed by the drive element 5.
The output of the control circuit 20 is feedback-controlled so that the output of the adder 19 becomes constant. Further, the drive element 5 scans the sample 4 in the XY directions. XY at this time
The surface shape of the sample is displayed on the monitor unit 21 by the directional scanning signal and the control signal of the control circuit 20.

According to this embodiment, high speed control is possible.

[0021]

[Embodiment 2] FIGS. 7 and 8 show the present embodiment, FIG. 7 is a schematic configuration diagram, and FIG. In this embodiment,
The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. The support 24 holds a sensor 27 and a sensor 28 in addition to the first embodiment. The probe support member 2 constitutes a diffraction grating as shown in FIG. 4 or 5.

As shown in the light projection arrangement diagram of FIG. 8, the sensors 27 and 28 are arranged in accordance with the diffraction angle diffracted in the direction perpendicular to the grating direction of FIG. 3 shown in the first embodiment. The sensors 27 and 28 are sensors such as a position sensor and a two-divided sensor.

The outputs of the sensor 27 and the sensor 28 enter the amplifier 31 and the amplifier 32, respectively, and input them to the adder 33. The output of the adder 33 is the drive element 5
It is input to the display unit 34 at the same time as the XY scanning signal generated in.

In this embodiment, the coarse movement mechanism 26, the probe 1, the probe support member 3, the drive element 5, the sensor 14, the sensor 15,
Laser light source 16, lens 22, amplifier 17, amplifier 1
8, the adder 19, the control circuit 20, and the monitor unit 21 operate in the same manner as in the first embodiment, and control the displacement of the probe support member 2 to be constant.

At this time, in order to detect the amount of bending displacement of the probe support member 2 due to friction on the sample surface, a diffraction grating 25 in which a vertical grating element is added to the diffraction grating 23 of the first embodiment.
And scans the probe support member 2 in the Y direction perpendicular to the paper surface. Therefore, the laser light is diffracted by the sensors 14 and 15 and also diffracted by the sensors 27 and 28.

The change in the light position on the sensor 27 and the sensor 28 is calculated by the amplifier 31, the amplifier 32 and the adder 33, which have the same functions as the amplifier 17, the amplifier 18 and the adder 19 of the first embodiment, and the deflection displacement. The quantity is displayed on the display 34. The display 34 can measure the surface characteristics of the sample 4 by synchronously displaying the XY scanning signal generated by the driving element 5 and the deflection displacement amount output from the adder 33.

According to this embodiment, the surface characteristics of the sample can be measured with high accuracy.

[0028]

Third Embodiment FIG. 9 is a schematic configuration diagram showing this embodiment.
In this embodiment, the coarse movement mechanism 26, the probe 1, the probe support member 2, the diffraction grating 23, the sensor 14, the sensor 15, the amplifier,
The configurations of the amplifier 18, the adder 19, the control circuit 20, and the monitor unit 21 are the same as those in the first embodiment.

The XY fine movement mechanism 45 is fixed by the coarse movement mechanism 26, holds the sample 4, and operates in the planes X and Y parallel to the plane perpendicular to the paper surface and to the left and right. The Z fine movement mechanism 35 holds the probe support member 2, is held by the coarse movement mechanism 29, and moves in the Z direction. The XY fine movement mechanism 45 and the Z fine movement mechanism 35 are composed of a piezoelectric actuator such as a cylindrical piezoelectric element.

The laser light source 16, the lens 22, and the optical isolator 42 are coaxially arranged, and the dichroic mirror 4 is used.
The light polarized by 3 is arranged so that it can be projected onto the diffraction grating 23 through an objective lens 44 arranged at a position facing the diffraction grating 23. The angle fine movement mechanism 46 holds the dichroic mirror 43 and constitutes a rotation mechanism about the optical center axis.

The objective lens 44, the prism 38, the eyepiece lens 36, the half mirror 39, the illumination lens 40 and the light source 41 have the structure of an ordinary microscope. The camera 37 is arranged at the image forming position of the objective lens 44, and its output is connected to the video monitor 48. The infrared cut filter 47 is arranged between the half mirror 39 and the dichroic mirror 43.

In this embodiment, the coarse movement mechanism 26, the probe 1, the probe support member 2, the drive element 5, the sensor 14, the sensor 15,
The amplifier 17, the amplifier 18, the adder 19, the control circuit 20, and the monitor unit 21 operate in the same manner as in the first embodiment. The laser light emitted from the laser light source 16 is reflected by the lens 2
2, passes through the optical isolator 42, the dichroic mirror 43, and the objective lens 44, and is projected onto the diffraction grating 23.

The optical isolator 42 has a function of preventing the 0th-order diffracted light reflected on the diffraction grating 23 from returning to the laser light source 16. The dichroic mirror 43 functions to align the optical axis of the optical system of the microscope component with the optical axis of the laser light source 16, reflects infrared light emitted from the laser light source 16, and transmits visible light. . With this configuration, the surfaces of the probe support member 2 and the sample 4 can be observed with a microscope, and at the same time, laser light can be projected onto the diffraction grating 23.

The light source 41, the illumination lens 40 and the half mirror 39 illuminate the sample surface as epi-illumination for a microscope. The prism 38 displays the observation image on the eyepiece 36 and the camera 3.
It works to distribute to 7. The video monitor 48 monitors the observation image captured by the camera. The infrared cut filter 47 prevents the infrared light reflected by the diffraction grating 23, which is harmful during observation, from passing through the dichroic mirror 43 without being completely reflected by the eye 49 or the camera 37. Has the function of cutting infrared rays.

The angle fine movement mechanism 46 is an angle correction adjustment mechanism of the dichroic mirror 43, and when the probe support member 2 is mounted at an inclination, the diffraction angle of the laser beam is detected by the sensor 1.
Laser light source 16
The optical axis of is rotated by the dichroic mirror 43 to change the projection angle so that the diffraction angle is changed so that the laser light is incident on the sensors 14 and 15. Coarse movement mechanism 29
Adjusts the probe support member 2 with respect to the objective lens 44,
It has a function to change the projection position of laser light.

According to this embodiment, the surface of the sample can be optically observed.

[0037]

As described above, according to the surface profile measuring apparatus of the present invention, the surface observation capable of high speed measurement can be performed with a compact structure.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing a diffraction grating.

FIG. 3 is a schematic plan view showing an example of the shape of a diffraction grating.

FIG. 4 is a schematic plan view showing an example of the shape of a diffraction grating.

FIG. 5 is a schematic plan view showing an example of the shape of a diffraction grating.

FIG. 6 is a schematic configuration diagram showing a first embodiment.

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

FIG. 8 is a light emitting layout diagram showing a second embodiment.

FIG. 9 is a schematic configuration diagram showing a third embodiment.

FIG. 10 is a schematic configuration diagram showing a conventional example.

[Explanation of symbols]

 1 probe 2 probe support member 3 diffraction grating 4 sample 5 driving element 6 projection light 7 diffracted light 8 displacement detector 29 controller

Claims (1)

[Claims] 1. A probe for detecting a force acting between the probe and a sample surface, a probe support member for supporting the probe, a displacement detector for detecting displacement of the probe, the sample surface and the probe. Needle and 3
In a surface shape measuring device for observing a sample surface having a driving element for moving the two-dimensionally relatively, and a controller for keeping the probe and the sample surface at a constant position based on the output of the displacement detector, A surface shape measuring apparatus characterized in that a displacement detecting surface of a probe supporting member is composed of a diffraction grating in one or more directions.