JPH11118813A - Atomic force microscope with solution cell - Google Patents

Abstract

(57) [Problem] To eliminate the influence of bubbles remaining in a solution by an atomic force microscope for observing a sample in the solution. A cantilever holder, on which a cantilever is fixed, and a sample mounted on a piezo scanner for three-dimensionally scanning the sample, are sealed by a deformable seal. , Solution 4 is filled. The incident light N from the laser light source is reflected on the back surface of the cantilever, and a change in the direction of the reflected light H is detected by the light receiver. The direction of the reflected light H changes according to the unevenness of the sample surface, and the direction of the reflected light H changes. However, the piezo scanner 6 is controlled so as to cancel the change, and the unevenness of the sample can be observed and measured in the solution. . The inner upper surface of the cantilever holder 2 is inclined, and the air bubbles 5 remaining in the solution gather at the upper corner and deviate from the optical paths of the incident light N and the reflected light H,
Does not interfere with measurement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an atomic force microscope having a solution cell for observing a sample in a solution (or generally a liquid) as it is.

[0002]

2. Description of the Related Art When observing a sample in a solution with an atomic force microscope, the area around the sample together with the cantilever is filled with the solution, and the vertical movement of the cantilever when the sample is scanned three-dimensionally causes the shape of the sample surface to change. Observation and measurement are performed.

FIG. 2 shows an example of a conventional atomic force microscope equipped with a solution cell. The solution cell 18 includes a cantilever holder 12 having a cantilever 11 mounted inside and a seal 13.
Consists of The space between the piezo scanner 16 that moves the sample 17 three-dimensionally and the cantilever holder 12 is sealed with a seal 13, and the interior space is filled with a solution 14. The distance between the cantilever 11 and the surface of the sample 17 is adjusted to a distance at which an atomic force can be measured. Since the cantilever holder 12 is fixed to the frame of the apparatus, and the seal 13 is made of a soft material such as an O-ring, the sample 17 placed on the piezo scanner 16 is finely scanned by the piezo scanner 16. Is the cantilever 1
1 is scanned.

The cantilever holder 12 is formed of a transparent material, and the incident light N from the laser light source irradiates the back of the tip of the cantilever 11, and the reflected light H is composed of a photodiode having a light-receiving surface divided into two. The shift in the reflection direction of the reflected light H is detected by the light receiver. The direction of the reflected light H changes according to the irregularity of the sample surface, and the direction of the reflected light H changes. By controlling the piezo scanner 16 to cancel the change, it is possible to observe the irregularity of the sample surface and measure the shape. it can.

Although the inside of the solution cell 18 is filled with the solution 14, it is difficult to expel all the bubbles when the solution 14 is injected. Therefore, the bubbles 15 often remain in the solution cell 18.

[0006]

In the above-mentioned conventional solution cell, it is difficult to prevent air bubbles from remaining inside.
As shown in FIG. 2, if the bubble 15 happens to stay at a position corresponding to the optical path of the incident light N and the reflected light H, the scattered light S will be generated at the bubble 15 portion. Since the scattered light S becomes a background with respect to the light receiver, there is a problem that the signal-to-noise ratio is reduced and the measurement accuracy of the sample shape is deteriorated. In addition, if bubbles move due to vibration or the like during the measurement, the optical paths of the incident light N and the reflected light H slightly change due to the relationship between the refractive index and the like, which also deteriorates the measurement accuracy of the sample shape.

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide an atomic force microscope with a solution cell always having high measurement accuracy without being affected by bubbles remaining in the solution cell. Aim.

[0008]

In order to solve the above problems, the present invention provides an atomic force microscope having a solution cell for observing a sample surface in a solution. It is characterized by being inclined with respect to.

Even if bubbles remain in the solution cell when the solution is injected into the solution cell, the bubbles rise along the inclined surface because the upper portion of the inner surface of the solution cell is inclined with respect to the horizontal plane. As a result, it will be collected in the corner of the solution cell. Therefore, bubbles do not stay in the path of the incident light irradiated on the cantilever or the reflected light reflected by the cantilever, and scattered light that hinders measurement is not generated. At the same time, the optical path does not fluctuate due to bubbles, so that the measurement accuracy as an atomic force microscope is improved.

[0010] The solution referred to herein is not limited to pure water or an aqueous solution containing required components, but also includes oils and organic solvents appropriately selected depending on the sample to be measured.
It refers to all liquids.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a view showing a part of a solution cell 8 which is a main part of an atomic force microscope with a solution cell of the present invention.

The space between the cantilever holder 2 in which the cantilever 1 is fixed and the piezo scanner 6 for three-dimensionally scanning the placed sample 7 is sealed by an O-ring seal 3. Solution 4 is full. The outer shape of the cantilever holder 2 is cylindrical,
Piezo scanners are also generally cylindrical. The cantilever holder 2 is formed using a transparent material such as glass or plastic so that the upper surface 9 inside is inclined with respect to a horizontal plane. The incident light N of the laser beam is emitted from the outside of the solution cell 8 to the back surface of the tip of the cantilever 1, and the reflected light H therefrom is detected by a light receiver such as a photodiode having a light-receiving surface divided into two, and the reflected light H Is detected in the reflection direction. The deflection of the cantilever 1 is detected by this optical lever mechanism.

The distance between the cantilever 1 and the surface of the sample 7 is previously adjusted to a distance at which the measurement of the atomic force between the cantilever 1 and the surface of the sample 7 can be performed. The cantilever holder 2 is fixed to a frame or the like of the device.
Since the seal 3 is made of a soft material such as a rubber O-ring, the sample 7 placed on the piezo scanner 6 is finely scanned two-dimensionally in the horizontal direction.
Is scanned with respect to the cantilever 1.

When the piezo scanner 6 is scanned two-dimensionally in the horizontal direction, the cantilever 1 moves up and down according to the unevenness of the sample surface, and the direction of the reflected light H changes. , The amount of vertical movement of the piezo scanner 6 corresponds to the unevenness of the sample surface, so that the unevenness of the sample surface can be observed and measured based on the amount of movement.

The inner upper surface of the cantilever holder 2 is formed so as to be inclined with respect to a horizontal plane. When injecting the solution 4 into the solution cell 8, it is difficult to completely eliminate bubbles, and in many cases, bubbles remain inside the solution cell 8.
Since the bubbles (air) are lighter than the solution 4, they move to the upper part of the solution cell 8, but the upper surface 9 inside the solution cell 8 is inclined, so that the bubbles 5 gather in the corner as shown in FIG. Become. Since the cantilever 1 is arranged substantially at the center of the solution cell 8, the incident light N and the reflected light H applied to the tip thereof also pass near the center of the solution cell 8.
Therefore, the bubble 5 does not stay at the optical path position of the incident light N and the reflected light H, and does not affect the measurement.

In the cantilever holder constituting the solution cell illustrated in FIG. 1, the inner upper surface 9 is inclined and the outer surface is horizontal. However, the solution cell of the present invention has not only this form but also an outer surface. It may be inclined so as to be parallel to the inner surface. Further, the seal for sealing the solution cell is not limited to a rubber O-ring, and the shape is not limited as long as it is a deformable material.

In FIG. 1, the optical paths of the incident light and the reflected light are both affected by the refraction of light generated at the boundary between the solution 4 and the cantilever holder 2 and at the boundary between the cantilever holder 2 and the external space. Although it is neglected, in an actual apparatus, a light receiver and the like are arranged in consideration of the influence of refraction.

[0018]

According to the atomic force microscope with a solution cell of the present invention, since the upper surface inside the solution cell is inclined, air bubbles remaining inside the solution cell move to the corner of the solution cell and obstruct the optical path of the light lever. And never. Therefore, scattered light from bubbles serving as a background is not generated, and at the same time, the optical path does not fluctuate due to the bubbles, so that the measurement accuracy as an atomic force microscope is improved.

[Brief description of the drawings]

FIG. 1 shows a main part of an atomic force microscope according to an embodiment of the present invention.

FIG. 2 shows a main part of an atomic force microscope equipped with a conventional solution cell.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cantilever 2 ... Cantilever holder 3 ... Seal 4 ... Solution 5 ... Bubbles 6 ... Piezo scanner 7 ... Sample 8 ... Solution cell 9 ... Top surface 11 ... Cantilever 12 ... Cantilever holder 13 ... Seal 14 ... Solution 15 ... Bubbles 16 ... Piezo scanner 17: sample 18: solution cell N: incident light H: reflected light S: scattered light

Claims (1)

[Claims] 1. An atomic force microscope having a solution cell for observing a sample surface in a solution, wherein an upper portion of an inner surface of the solution cell is inclined with respect to a horizontal plane. Force microscope.