JPH04171646A - Interatomic force microscope device - Google Patents

Abstract

PURPOSE:To facilitate the positioning of a measurement position and obtain a clear optical microscope image without requiring professional knowledge by forming a specific optical displacement detecting means. CONSTITUTION:A sensor head 8 is constituted of a mirror 82, the first half mirror 84, the second half mirror 85, a reflection objective lens 86, the third half mirror 87, a CCD camera 88, and a photo-diode 89. The white light 83 is radiated from a white light source, and the sensor head 8 is vertically moved by a sensor head vertical movement system to focus an optical microscope image on a sample 6. The sample 6 is horizontally moved to the measurement position by an XY rough movement system in the focused state. The measurement position on the sample 6 is positioned. The positioning of the measurement position can be easily performed, and a clear optical microscope image can be obtained without requiring professional knowledge.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an atomic force microscope device that measures the three-dimensional shape of a sample surface using atomic force, and particularly relates to an atomic force microscope device that measures the three-dimensional shape of a sample surface using atomic force. The present invention relates to an atomic force microscope device that allows for easy selection and to obtain clear optical microscope images without requiring specialized knowledge.

(Prior Art) In general, an atomic force microscope (AFM) is capable of displacing or vibrating the tip of the cantilever due to the atomic force generated between the sample and the tip of the cantilever when the cantilever is brought close to the sample on the order of angstroms. Detect and
This is used to measure the surface shape of a sample. In this case, the cantilever is formed from a thin metal foil, has a tip for detecting atomic force disposed at its tip, and is fixed to the main body of the atomic force microscope device by force on its terminal end.

By the way, in this type of atomic force microscope device, the method for detecting the displacement or vibration of the cantilever is to irradiate the cantilever with a light beam and receive the reflected light, in order to detect the displacement or vibration of the cantilever. The so-called optical lever method is often used. Furthermore, as another method, an optical heterodyne method is used in which a light beam is irradiated onto a cantilever and a phase change of the light applied from the cantilever is detected as a result. Furthermore, recently, in a method using a tip probe (critical angle method) as an optical detection method, an apparatus combined with an optical microscope has been proposed.

However, most of the optical methods for detecting the displacement of a cantilever are used only for detecting the displacement of the cantilever, and therefore, when positioning a measurement point on a sample, it is necessary to use another optical microscope or the like. In this case, since the cantilever and sample are observed obliquely,
Positioning was extremely rough.

In addition, with a device that combines an optical microscope and a tip-type cantilever displacement detection system, when attempting to observe the position of a sample using the same optical path, aberrations occur due to the use of an objective lens made of glass, resulting in sharp images. Obtaining a clear optical microscope image requires specialized optical knowledge, and tip probe two surface roughness meters generally use two optical paths for the optical microscope and the tip probe.

However, in such a device, two optical systems are required, and as a result, the optical system itself has a complicated configuration.

(Problem to be solved by the invention) As described above, in the conventional atomic force microscope device,
There are problems in that it is not only difficult to position (select) a measurement point, but also that specialized knowledge is required to obtain a clear optical microscope image.

An object of the present invention is to provide an atomic force microscope device with a simple configuration, which allows easy positioning (selection) of measurement points, and can obtain clear optical microscope images without requiring specialized knowledge. It's about doing.

[Configuration of the Invention (Means for Solving the Problem) In order to achieve the above object, the present invention includes a cantilever that detects the atomic force generated between the sample and the sample that is provided at a predetermined distance. , an atomic force microscope device comprising: an optical displacement detection means disposed opposite to the side of the cantilever opposite to the sample and detecting displacement or vibration of the cantilever; white light output from a white light source; and a first half mirror that reflects a part of the laser light output from the laser light source, a second half mirror that reflects a part of the light reflected by the first nof mirror, and a second half mirror. - while making the light reflected by the cantilever enter the cantilever,
a reflective objective lens that receives light reflected by the cantilever; a third half mirror that receives the light received by the reflective objective lens via a second half mirror and branches it into two; and a third half mirror that receives the light that is reflected by the cantilever. - a camera that receives one light from the third half mirror and captures an image, and a light amount detection means that receives the other light from the third half mirror and detects the amount of light,
It constitutes an optical displacement detection means.

(Function) Therefore, in the atomic aperture force microscope apparatus of the present invention, it is possible to more easily position the measurement point of the sample than in the conventional apparatus without an optical microscope. Furthermore, since the irradiation position of the laser beam on the cantilever can be confirmed using the same optical microscope, the measurement can be easily performed. Furthermore, compared to a conventional device that combines an optical microscope and a probe-type cantilever displacement detection system, the optical system can be assembled with a simple one, so no specialized optical knowledge is required.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of the overall configuration of an atomic force microscope apparatus according to the present invention. In FIG. 1, a base 1 is provided with two coarse movement mechanisms 2, an xyz coarse movement mechanism 3, and an xyz fine movement mechanism 4. Further, the xyz fine movement mechanism 4 is provided with a sample stage 5 on which a sample 6 is placed so that the sample 6 can be moved in three dimensions.

On the other hand, the base 1 is provided with a sensor head vertical movement mechanism 7, and the sensor head vertical movement mechanism 7 is provided with a sensor head 8 which is an optical displacement detection means, and the sensor head 8 is moved vertically with respect to the base 1. It allows you to move. Further, the base 1 is provided with an XY moving mechanism 9 for the lever, and the lever holder 1 is attached to the XY moving mechanism 9 for the lever.
Further, a cantilever 11 is provided on the lever holder 10 so that the cantilever 11 can be moved horizontally with respect to the base 1. Here, cantilever 1
1 is provided with a chip 12 for detecting atomic force on one surface (side surface of the sample 4), and is placed between the sample 6 and the sensor head 8 to detect the atomic force generated between the sample 6 and the sensor head 8. I try to do that.

FIG. 2 is a schematic diagram showing a detailed configuration example of the sensor head 8. As shown in FIG. Note that an optical lever method is used as the displacement detection means.

In FIG. 2, the sensor head 8 includes a mirror 82 that reflects laser light 81 output from a laser light source, which will be described later.
and a first half mirror 84 that reflects white light 83 output from a white light source, which will be described later, and a portion of the laser beam 81 reflected by the mirror 82;
a second half mirror 8 that reflects a part of the light reflected by the
5, a reflective objective lens 86 that allows the light reflected by the second half mirror 85 to enter the cantilever 11 and receives the light reflected by the cantilever 11;
The light received by the reflective objective lens 86 is received through the second half mirror 85, the third half mirror 87 splits into two, and one of the lights from the third half mirror 87 is received. The photodiode 89 is a light amount detection means that receives the other light from the third half mirror 87 and detects the amount of light. Here, each element except the laser beam 81 and the photodiode 89 constitutes an optical microscope.

The control, drive, and display of each element in the sensor head 8 is performed by a control, drive, and display device configured as shown in FIG. 3. In FIG. 3, 31 is a white light source, 32 is a laser light source, 33 is a CRT monitor, 3
Reference numeral 4 indicates a data display/recording device, and reference numeral 35 indicates a control circuit.

That is, an image obtained by the CCD camera 88 is displayed on the CRT monitor 33.

Furthermore, based on the detection signal from the photodiode 89, the control circuit 35 outputs a control signal to the XYZ fine movement mechanism 4 to keep the distance between the cantilever 11 and the sample 6 constant, and the same signal is also used to display and record data. The data is output to a device 34 for storage and display.

Next, the operation of the atomic force microscope apparatus of this embodiment configured as described above will be explained.

First, the operation for positioning the measurement point on the sample 6 will be described.

First, white light 83 is irradiated from the white light source 31, and the sample 6 is
In order to focus the optical microscope image upward, the sensor head 8 is moved up and down by the sensor head up and down movement mechanism 7. Then, in a focused state, the sample 6 is horizontally moved by the XY coarse movement mechanism 3 to a measurement location. Through the above operations, the measurement location on the sample 6 is positioned (selected).

Also, at this time, since the reflective objective lens 86 is used,
A clear optical microscope image without aberrations can be easily obtained.

Next, the sensor head 8 is moved upward by the sensor head vertical movement mechanism 7, and the cantilever 11 is moved horizontally by the lever XY movement mechanism 9 so that it enters the center of the field of view of the image of the optical microscope. Thereafter, the sensor head 8 is moved to focus on the cantilever 11. And this state is C
This can be checked on the RT monitor 33 and the optical path -10= to the cantilever 11 can be easily adjusted.

Next, laser light? A laser beam 81 is also irradiated from R32, and the position of the cantilever 11 is adjusted by the lever XY movement mechanism 9 while checking the irradiation position of the cantilever 11 and the laser beam 81 on the CRT monitor 33. In this case, C.C.
Since the relative position between the D camera 88 and the photodiode 89 is constant, the laser beam 81 is successfully incident on the photodiode 89 in this state.

Next, the white light source 31 is turned off and the irradiation of the white light 83 is stopped. Then, while measuring the amount of laser light 81 incident on the photodiode 89, the sample 6 is brought close to the cantilever 11 by the Z coarse movement mechanism 2. As a result, when a force such as an atomic force acts between the cantilever 11 and the sample 6, the tip of the cantilever 11 is displaced or vibrated and the optical path changes, so the amount of light to the photodiode 89 changes.

While measuring this amount of light, the surface shape of sample 6 (
unevenness) is measured.

As described above, the atomic force microscope device of this embodiment provides the following various effects.

(a) Compared with a conventional device without an optical microscope, the device of this embodiment makes it possible to easily position (select) a measurement location on the sample 6.

(b) Since the irradiation position of the laser beam 81 on the cantilever 11 can be confirmed using the same optical microscope, it becomes possible to easily determine nj.

(c) Compared to a conventional device that combines an optical microscope and a tip lever displacement detection system, the optical system of this example can be assembled with a simple device, so it requires no specialized optical knowledge. do not need.

(d) Since the reflective objective lens 86 is used, the optical system can be configured simply as an optical path for the laser beam 81 and the white light 83.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be similarly implemented in the following manner.

(a) In the above embodiment, a photodiode with one light-receiving surface is used, but a split-type photodiode in which the light-receiving surface is divided by -12 may also be used.

(b) It is also possible to obtain an uneven image by vibrating the cantilever with a piezoelectric element and measuring changes in the vibration frequency.

(C) In the above embodiment, a case was described in which an optical lever method was used to measure the displacement of the cantilever. However, even if a laser interferometer is used as shown in FIG. 4, the same effect as described above can be obtained. It is something that can be done.

[Effects of the Invention] As explained above, according to the present invention, it is possible to easily position (select) a measurement point and obtain a clear optical microscope image without requiring specialized knowledge. A simple atomic force microscope device can also be provided.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram showing an example of an atomic force microscope device according to the present invention, Fig. 2 is a schematic diagram showing a detailed configuration example of a sensor head in the same embodiment, and Fig. 3 is a control diagram in the same embodiment. - A block diagram showing an example of the configuration of the drive/display device. FIG. 4 is a schematic diagram showing another embodiment of the atomic force microscope device according to the present invention. 1...Base, 2...2 coarse movement mechanism, 3...xyz coarse movement mechanism, 4...xyz fine movement mechanism, 5...sample stage, 6
... Sample, 7... Sensor head vertical movement mechanism, 8.
...Sensor head, 9...XY movement mechanism for lever,
10... Lever holder, 11... Cantilever,
12... Atomic force detection chip, 31... White light source, 32... Laser light source, 33... CRT monitor, 34
...Data display/recording device, 35...Control circuit, 8
DESCRIPTION OF SYMBOLS 1... Laser light, 82... Mirror, 83... White light, 84... First half mirror-185... Second half mirror-186... Second half mirror-187.
...Third half mirror-188...CCD camera, 8
9...Photodiode. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Scope of Claims] A cantilever for detecting atomic force generated between a sample and a sample provided at a predetermined distance; or an optical displacement detection means for detecting vibrations, the first half reflects the white light output from the white light source and a part of the laser light output from the laser light source. a mirror; a second half mirror that reflects a portion of the light reflected by the first half mirror; and the light reflected by the second half mirror is incident on the cantilever and is reflected by the cantilever. a reflective objective lens that receives the light received by the reflective objective lens; and a third mirror that receives the light received by the reflective objective lens via the second half mirror and branches it into two parts.
a half mirror, a camera that receives one of the lights from the third half mirror and captures an image, and a light amount detection means that receives the other light from the third half mirror and detects the amount of light. An atomic force microscope apparatus comprising: said optical displacement detecting means.