JP2853585B2 - Scanning probe microscope - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning probe microscope represented by a scanning tunneling microscope (STM) and an atomic force microscope (AFM).

[0002]

2. Description of the Related Art In a scanning probe microscope, a physical quantity generated by an interaction between a probe and a surface of the sample is obtained by scanning the probe or the sample by bringing the sample close to the probe arranged opposite thereto. It detects and measures the shape of the sample surface at atomic-level resolution.
M), an atomic force microscope (AFM), and the like.
A scanning tunnel microscope applies a voltage between a sample and a probe arranged opposite thereto, and scans the probe or the sample so that a tunnel current flowing between the two becomes constant.
It observes the shape of the sample surface at the atomic level resolution. In other words, utilizing the property that the tunnel current is uniquely determined by the distance between the probe and the sample, the height of the probe or the sample is controlled by a precision driving mechanism using a piezoelectric element or the like so that the tunnel current becomes constant. Then, the unevenness of the sample surface is measured by measuring the control amount.

An atomic force microscope measures a minute atomic force generated between an atom at the tip of the probe and an atom on the sample surface by bringing a probe supported by a cantilever or the like close to the sample surface. Using the property that the atomic force is uniquely determined by the distance between the probe and the sample, adjust the distance between the probe and the sample so that the atomic force is constant while scanning along the sample surface Then, the irregular shape of the sample surface is measured by a probe or a locus in the height direction of the sample.

Here, since the performance of such a scanning probe microscope is sensitively influenced by the delicate shape of the probe, damage or contamination of the tip of the probe has a great adverse effect on the measurement accuracy, and is originally a square. This causes a problem that a hole having a shape is measured in a circular shape. Therefore, it is necessary to replace the probe before it deteriorates.

A configuration of a cantilever portion of a conventional scanning probe microscope will be described with reference to FIG. Reference numeral 5a denotes a silicon nitride film cantilever holding a probe 5b at the tip, and the end in the opposite direction to the probe 5b is a cantilever support 5c.
It is stuck to. 5d is a cantilever holder, 15
One end is fixed to the cantilever holder 5d by a fixing screw 16 with a holding plate. Cantilever support 5c
Is pressed and held by the cantilever holder 5d by a holding plate 15 made of a plate-shaped spring material. By the way, in order to stably press and hold the cantilever support 5c, the pressing plate A has a size such that the pressing portion A covers substantially the entire cantilever support 5c. Therefore, the detachability of the cantilever support 5c holding the probe at the tip at the time of replacement is poor, and it is difficult to finely adjust the mounting position.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and makes it easy to replace the cantilever support holding the probe at the tip, thereby improving the measurement performance of the scanning probe microscope. An object of the present invention is to always enable measurement with a normal probe so as not to deteriorate.

[0007]

According to the present invention, a probe support holding a probe at the tip is pressed and held on a cantilever holder by wires held at both ends by a plate-like elastic body.

[0008]

The wire, which receives the spring force from the plate-like elastic body at both ends in the direction perpendicular to the axial direction, comes into contact in the width direction of the cantilever support, presses the cantilever support and holds it on the cantilever holder. Since only the wire is covered on the cantilever support, the cantilever support holding the probe at the tip has good detachability at the time of replacement and fine adjustment of the mounting position can be easily performed.

[0009]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
This will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes a sample holder on which a sample 1a to be measured is placed. Reference numeral 2 denotes a Z-axis fine movement mechanism for finely moving the sample 1a in the Z-axis direction via the sample holder 1, and a Z-axis driver 2a
Driven by 3 is a Z-axis fine movement mechanism 2 and a sample holder 1
Is an XY fine movement mechanism for finely scanning the sample 1a in the X and Y axis planes via the XY scanning driver 3a. An XY coarse movement stage 4 is driven by an XY coarse movement driver 4a.

Reference numeral 5a denotes a cantilever for holding the probe 5b in a replaceable manner, and reference numeral 6 denotes a displacement detector for measuring the distance between the probe 5b and the sample surface. Here, the distance between the probe 5b and the sample surface is, for example, in the case of a scanning tunnel microscope.
The tunnel current flowing between the probe 5b and the sample surface,
In the atomic force microscope, it is determined by detecting an atomic force generated between the probe 5b and the sample surface. This utilizes the property that the tunnel current or the interatomic force is uniquely determined by the distance between the probe and the sample, as described above.

Reference numeral 7 denotes a servo mechanism for driving and controlling the Z-axis fine movement mechanism 2 via the Z-axis driver 2a so that the output of the displacement detector 6 indicating the distance between the probe 5b and the sample surface is always constant. It is. Reference numeral 8 denotes an A / D converter, which A / D converts the output of the servo mechanism 7 and outputs the result to the control means 9.

Reference numeral 9 denotes drive control of the above-described Z-axis driver 2a, XY scanning driver 3a, and XY coarse movement driver 4a, and the shape of the sample surface is determined from the locus of the sample to be measured on the XY plane and the locus in the Z-axis direction. Control means for measuring the Reference numeral 10 denotes a display unit for displaying the obtained measurement data, which is constituted by a CRT or the like.

Next, the operation of the embodiment of the present invention will be described. First, the XY coarse movement stage 4 is driven via the XY coarse movement driver 4a, and the sample 1a is arranged immediately below the probe 5b. After adjusting the distance between the sample 1a and the probe 5b to a predetermined distance via the Z-axis driver 2a and the Z-axis fine movement mechanism 2, the Z-axis driver 2a is placed under the control of the servo mechanism 7, and the XY scanning driver is set. The XY fine movement mechanism 3 is driven via 3a to measure the surface shape of the sample 1a.

Next, the structure of the cantilever portion is shown in FIG.
This will be described with reference to FIG. Reference numeral 5a denotes a cantilever made of a silicon nitride film holding a probe 5b at the tip, and an end of the cantilever opposite to the probe 5b is fixed to a cantilever support 5c. 5
d is a cantilever holder, 11a is a stainless steel wire, and both ends are welded to the bifurcated (U-shaped) tip of the leaf spring 11. The end of the leaf spring 11 on the side opposite to the wire 11 a is fixed by a fixing screw 12 to the cantilever holder 5.
It is fixed to d. The cantilever support 5c is pressed and held by the cantilever holder 5d via the wire 11a by the spring force of the leaf spring 11, but the wire 11a
When only the half portion on the side of the cantilever 5a is in contact with the center portion of the cantilever 5a, there is no obstacle when grasping both sides for attachment and detachment.

In the above embodiment, the leaf spring 11 is a one-piece, two-pronged shape. However, the two ends of the wire 11a may be separately held by two independent leaf springs. Further, holding of both ends of the wire 11a to the leaf spring 11 may be achieved by pressing with a band and fixing with screws instead of welding. In the above embodiment, the number of wires 11a is one, but two wires may be attached to the leaf spring 11 in parallel. Further, the shape may be a narrow rectangular cross section instead of the round bar. Wire 11
The material of a may be any material other than stainless steel, as long as it can withstand pressure holding in terms of strength and has corrosion resistance.

The deterioration of the performance of the probe 5b is measured by placing a sample for inspection whose shape is known in advance on the sample holder 1 and measuring the result. It can be confirmed by checking whether the shape is not deformed and displayed.

[0017]

As described above, according to the present invention, since only the wire is covered on the cantilever support and there is no obstacle in grasping the side surface of the cantilever support, the cantilever support can be attached and detached at the time of replacement. It is easy to perform fine adjustment of the mounting position.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a scanning probe microscope according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a cantilever portion of the scanning probe microscope according to the embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a cantilever portion of a conventional scanning probe microscope.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Sample holder 1a ... Sample 2 ... Z-axis fine movement mechanism 3 ... XY fine movement mechanism 4 ... XY coarse movement stage 5a ... Cantilever 5b ... Probe 5c ... Cantilever support body 6 ... Displacement detector 7 ... Servo mechanism 9 ... Control means 10 ... Display means 11 ... Leaf spring 11a ... Wire

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01N 37/00 G01B 21/30 G01B 7/34

Claims (1)

(57) [Claims] 1. A method in which a sample and a probe disposed opposite to the sample are brought close to each other, and the probe or the sample is scanned to detect a physical quantity generated by an interaction between the probe and the sample surface, thereby detecting a physical amount of the sample surface. In a scanning probe microscope for measuring a shape at an atomic level resolution, a probe support holding a probe at the tip is pressed and held on a holder by wire-like members held at both ends by an elastic body. Features scanning probe microscope.