KR100548724B1 - AFM with dual tip and its test method - Google Patents

Abstract

The present invention relates to a dual tip atomic force microscope and a method for measuring the same. More specifically, the piezoelectric sensor, the cantilever, and the tip in an atomic force microscope for measuring the roughness of the surface of the sample by measuring the movement of the cantilever by the force between the sample and the tip atom. To install Dual to enable dual scan.

The dual tip atomic force microscopy method of the present invention detects the force between the atoms of the sample surface to be measured and the tip set to the plurality, and the plurality of cantilevers set to the plurality of tips bend up and down by the detected force. A plurality of piezoelectric sensors connected to the plurality of cantilevers to move a sample surface to detect a movement path of the cantilever, recognize a sample surface profile with the sensed data, and a measurement range between the plurality of tips set to a predetermined region When it is set to overlap, the technical feature consists in comparing the sample surface profile respectively recognized in the overlapped areas, and when the error of the compared data is more than a certain range, the area is measured again.

A dual tip atomic force microscope to achieve the above method of the present invention comprises a plurality of tips for sensing a mutual force with atoms of a sample surface to be measured; A plurality of cantilevers connected to the plurality of tips to bend up and down by the sensed force to move a sample surface; A plurality of piezoelectric sensors connected to the cantilever and configured to sense a movement path of the cantilever; A recognition unit for recognizing a sample surface profile with data sensed by the plurality of tips, cantilevers and piezoelectric sensors; A comparison unit comparing the sample surface profiles respectively recognized in the overlapped areas when the measurement range between the plurality of tips is set to overlap a predetermined area; Another technical feature is that the controller is configured to measure the area again when the error of the compared data exceeds a predetermined range.

AFM, dual tip, cantilever, piezoelectric sensor.

Description

Dual tip atomic force microscope and its measuring method {AFM with dual tip and its test method}             

1 illustrates a cantilever including a general piezoelectric sensor.

2 is a schematic diagram illustrating the principle of an AFM according to the present invention.

Figure 3 is a schematic diagram showing the profile results measured by the dual tip AFM measurement method of FIG.

<Description of the symbols for the main parts of the drawings>

10 scanner 20 piezoelectric sensor

30: cantilever 40: tip

50: sample

The present invention relates to a dual tip nuclear microscope and a method for measuring the same. More specifically, the piezoelectric sensor and the cantilever in an atomic force microscope for measuring the roughness of the surface of the sample by measuring the movement of the cantilever by the force between the sample and the tip atom. In other words, the tip is installed in dual to enable dual scanning.

Atomic Force Microscopes, commonly referred to as AFMs, are designed to analyze surfaces using interatomic forces to observe at the atomic magnification of a sample. Because of the force between atoms, almost all samples such as conductors, semiconductors, magnetic materials, and dielectrics can be easily observed in the air regardless of the conductivity of the sample.

At this time, the AFM measures the degree to which the cantilever is bent by the force acting between the atoms and the atoms of the sample by using a tip attached to a soft spring called a cantilever manufactured by micromachining.

Therefore, the cantilever is made to bend up and down easily even by a minute force, and the tip has a pointed needle, that is, a probe, about the size of several atoms. Approaching the probe surface to the sample surface, the attraction between the atoms at the tip of the probe and the atoms at the sample surface is attracted to each other, or the repulsive force is pushed. The AFM measures this force in an appropriate manner to produce an electrical signal. After conversion, this signal is inversely fed back to maintain a constant distance between the probe and the sample to provide three-dimensional information about the surface of the sample.

Typically in AFM operation, in contacting mode, a sharp tip is mounted at the end of the cantilever, which tip is placed on the sample surface with a very small tracking force (10 ^-5 to 10 ^-10 N).

The appearance of surface topography is very high resolution. An image showing the position of each atom is customarily obtained. In the second mode of operation, the tip maintains a short distance of about 5 to 500 angstroms from the sample surface, such that the tip is deflected by various forces including electrostatic, magnetic and van der Waals forces between the sample and the tip.

AFM can image not only insulating surfaces but also conductive surfaces with atomic resolution. Conventional AFM has a sensitivity of 0.1 Angstroms and a spring constant of about 1 Newton per meter (1 N / m) in measuring displacement. In addition, the cantilever must be mounted to allow access and contact with the sample.

Several methods of detecting cantilever deflection may utilize sub-angstrom sensitivity, including vacuum tunneling, optical interference, optical beam deflection, and capacitive techniques.

However, at present, such a conventional technology is still limited in improving the sensitivity of the piezo-resistive sensor. Currently, the cantilever uses a combination of various methods. However, there are still limitations to improving sensitivity.

The reason for further improving the sensitivity of the piezo-resistive sensor is not only the efficiency of sensing but also the secondary advantage of easier technology development of peripheral circuits. Therefore, more technology development is required to improve the sensitivity of the piezo-resistive sensor.

Although optically operated AFM is very accurate, it requires some optical elements and fine alignment, which makes it difficult to manufacture and difficult to operate, and also introduces problems that can cause errors when measuring small steps with a single tip. .

Accordingly, the present invention is to solve the above-mentioned disadvantages and problems of the prior art, in order to minimize the errors that may occur when measuring the sample with a single tip, the piezoelectric sensor, cantilever, tip installed in dual (dual) It is an object of the present invention to provide a dual tip nuclear microscope measurement method to enable dual scan.

The object of the present invention is to detect the force between the atoms of the sample surface to be measured and the tip set to the plurality, the plurality of cantilever set to the tip set to the plurality is bent up and down by the detected force to move the sample surface And a plurality of piezoelectric sensors connected to the plurality of cantilevers detect the movement path of the cantilever, recognize the sample surface profile using the sensed data, and set the measurement range between the plurality of tips to overlap a predetermined region. When this is achieved by a dual tip atomic force microscopy method consisting of comparing the sample surface profiles respectively recognized in the overlapped areas and re-measuring the area when the error of the compared data is above a certain range.

A dual tip AFM which achieves the above method of the present invention comprises: a plurality of tips configured to sense a mutual force with atoms of a sample surface to be measured; A plurality of cantilevers connected to the plurality of tips to bend up and down by the sensed force to move a sample surface; A plurality of piezoelectric sensors connected to the cantilever and configured to sense a movement path of the cantilever; A recognition unit for recognizing a sample surface profile with data sensed by the plurality of tips, cantilevers, and piezoelectric sensors; A comparison unit comparing the sample surface profiles respectively recognized in the overlapped areas when the measurement range between the plurality of tips is set to overlap a predetermined area; When the error of the compared data is a predetermined range or more, the control unit for measuring the area again.

In the dual tip atomic force microscopy method of the present invention, a piezoelectric sensor, a cantilever, and a tip are dually installed in an atomic force microscope in which the cantilever moves by a force between a sample and a tip atom to measure the roughness of a sample surface. Dual scan capability enables sample surface data to be measured twice as fast, reducing measurement time.

Details of the above object and technical configuration and the effects thereof according to the present invention will be more clearly understood by the following detailed description with reference to the drawings showing preferred embodiments of the present invention.

1 illustrates a cantilever including a general piezoelectric sensor. FIG. 1 is a perspective view illustrating a substrate 9 having a tip, a sensing unit 4 acting as a piezoelectric resistance by doping boron on the substrate 9, and the sensing unit 4. It consists of a sensing signal transmission unit 6 for transmitting an electrical signal.

In addition, an electrical signal is not generated between the contact portion 7 for forming an ohmic contact between the sensing signal transmitting portion 6 and the sensing portion 4 and the substrate 9 and the sensing signal transmitting portion 6. The insulating film 8 which prevents it is further comprised.

Since the sensitivity of piezo-resistive sensors (piezoresistor) incorporating the piezo-resistance sensor as described above is very important, various methods have been proposed to increase the sensitivity. There is.

In the AFM measuring method for measuring the roughness of the surface of the sample, the three-dimensional surface profile can be obtained by measuring the movement of the cantilever due to the force of the atom between the sample and the tip line by line.

FIG. 2 is a schematic diagram showing the principle of AFM according to the present invention. Referring to the configuration of FIG. 2, a scanner 10, a piezoelectric sensor 20, a cantilever 30, a tip 40, and a sample 50 may be used. It can be seen that, in particular, it can be seen that the piezoelectric sensor 20, the cantilever 30, the tip 40 is composed of a dual.

The principle of the AFM of FIG. 2 is to measure, by line, that the cantilever 30 bends up and down by a force between the atoms of the tip 40 and the surface of the sample 50. 20), since the cantilever 30 and the tip 40 are configured in dual, the measurement time can be shortened by measuring a range in which the plurality of tips 40 do not overlap each other. In addition, as a method for preventing an error caused by measuring a very fine step, a plurality of tips 40 set a certain range so that they can be overlapped with each other to measure the error between each tip (40) Measure the part where the error occurred again.

3 is a schematic view showing a profile result measured by the dual tip nuclear microscope measurement method of FIG.

The present invention is not limited to the above-described embodiments, and many variations and modifications can be understood by those skilled in the art within the scope of the present invention. In the above-described embodiment, the piezoelectric sensor 20, the cantilever 30, the tip 40 are configured in dual, but the number of each can be set higher than necessary.

Therefore, the dual tip atomic force microscopy method of the present invention provides dual scanning by installing a piezoelectric sensor, a cantilever, and a tip in an AFM so that the sample surface data can be measured twice as fast and the measurement time can be measured. Can be reduced.

In addition, by measuring a range in which a plurality of tips do not overlap each other, it is possible to shorten the measurement time, and by setting a predetermined range so that a plurality of tips overlap each other and measure the results of the measurement of each tip. When an error occurs, the part where the error occurred can be measured again, whereby a very fine step can be measured.

Claims (6)

In the roughness measurement method of the sample surface by an atomic force microscope, A first step of detecting the force between the atoms of the surface of the sample 50 to be measured and the tip 40 is set to a plurality; A second step in which the plurality of cantilevers 30 set in the plurality of tips 40 are bent up and down by the sensed force to move the sample surface; A third step of sensing a moving path of the cantilever 30 by a plurality of piezoelectric sensors 20 connected to the plurality of cantilevers 30; A fourth step of recognizing a surface profile of the sample 50 using the sensed data; A fifth step of comparing the sample surface profiles respectively recognized in the overlapped areas when the measurement ranges between the plurality of set tips 40 overlap each other; And A sixth step of measuring the area again when an error of the compared data is greater than or equal to a predetermined range; Dual tip nuclear microscope measurement method characterized in that consisting of. The method of claim 1, In the fifth step, when the measurement ranges between the plurality of tips 40 are not overlapped, the dual tip nuclear microscope measurement method of recognizing a sample surface profile by combining the data sensed at each tip (40). The method of claim 1, Dual tip nuclear microscope measurement method characterized in that the number of the plurality of tips (40), cantilever (30), the piezoelectric sensor (20) can be adjusted as needed. In the atomic force microscope which measures the roughness of a sample surface, A plurality of tips 40 configured to sense a mutual force with atoms of the surface of the sample 50 to be measured; A plurality of cantilevers 30 connected to the plurality of tips 40 to bend up and down by the sensed force to move a sample surface; A plurality of piezoelectric sensors 20 connected to the cantilever 30 to sense a moving path of the cantilever 30; Recognition unit for recognizing the surface profile of the specimen 50 by the data sensed by the plurality of tips 40, the cantilever 30, the piezoelectric sensor 20; A comparison unit comparing the sample surface profiles respectively recognized in the overlapped areas when the measurement ranges between the plurality of tips 40 are set to overlap each other; Control unit to measure the area again when the error of the compared data is more than a certain range Dual tip atomic force microscope, characterized in that consisting of. The method of claim 4, wherein The recognition unit dual tip nuclear microscope, characterized in that for recognizing the movement of the cantilever 30 by Line (Line by Line). The method of claim 4, wherein Dual tip nuclear microscope, characterized in that the number of the plurality of tips 40, cantilever 30, the piezoelectric sensor 20 can be configured to be adjusted as necessary.

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