KR20110111581A - Atomic force microscope - Google Patents

Abstract

The present invention discloses an atomic force microscope capable of randomly scanning large area substrates at high speed. The microscope includes a substrate stage portion for supporting a substrate and moving horizontally, a scan head portion for scanning an upper portion of the substrate facing the substrate stage portion with a probe and a cantilever, a frame for supporting the scan head portion, A behavior stage portion for attaching and detaching the scan head portion to a frame and moving the scan head portion in a direction perpendicular to the substrate when the probe and the cantilever are replaced in the scan head portion, the behavior stage portion and the scan head portion And a micro-movement stage unit which connects the probe to the surface of the substrate during scanning of the scan head unit and spaces the probe from the surface of the substrate during horizontal movement of the substrate by the substrate stage unit.

Description

Atomic force microscope

The present invention relates to an atomic force microscope, and more particularly, to an atomic force microscope capable of measuring the surface of a substrate to the size of an atom.

Atomic Force Microscopes (AFMs) can measure down to the atomic level with probe tips scanned along the substrate surface. The probe may be scanned onto the substrate surface in a contact manner, a non-contact manner, an intermittent contact manner, or the like. Atomic Force Microscopy can be represented by imaging changes in position of the probe. In addition, the atomic force microscope can be applied to measure the frictional force, hardness, magnetic properties, electrical properties, electrochemical properties, capacitance of the substrate surface.

The problem to be solved by the present invention is to provide an atomic force microscope capable of measuring a large area substrate. Another object of the present invention is to provide an atomic force microscope capable of randomly measuring a large area substrate at high speed. There is.

The atomic force microscope of the present invention for achieving the above object, the micro-movement stage for rapidly approaching the probe to the surface of the substrate during scanning of the substrate surface, and rapidly moving the probe from the surface of the substrate during horizontal movement of the substrate Contains wealth. The microscope includes: a substrate stage portion supporting the substrate and moving horizontally; A scan head unit scanning an upper portion of the substrate facing the substrate stage unit with a probe and a cantilever; A frame supporting the scan head portion; A movement stage portion which detaches the scan head portion from the frame and moves the scan head portion in a direction perpendicular to the substrate when the probe and the cantilever are replaced in the scan head portion; And connecting the behavior stage part and the scan head part, and approaching the probe to the surface of the substrate during scanning of the scan head part and from the surface of the substrate during horizontal movement of the substrate by the substrate stage part. It includes an accessible variable stage spaced apart.

According to an embodiment of the present invention, the variable access stage unit may include a micro moving stage unit for raising and lowering the probe at intervals from nanometer units to sub-micro units on the substrate surface. The micro-movement stage unit may raise and lower the probe to about ± 100 ㎛ from the surface of the substrate.

According to another embodiment of the present invention, the micro moving stage may include a stacked piezoelectric ceramic bar that is contracted or expanded in the behavior stage. The stacked piezoelectric ceramic bar may include a plurality of piezoelectric plates stacked in one direction, stack electrodes formed between the plurality of piezoelectric plates, and a ground terminal and a power supply terminal alternately connected to the stack electrodes. In addition, the micro moving stage unit may further include a leaf spring which is lifted and lowered by the stack piezoelectric ceramic bar.

According to an embodiment of the present invention, the leaf spring is an atomic force microscope connected to the micro moving stage and the behavior stage.

According to another embodiment of the present invention, the scan head portion may include a scanner, and the scanner may include a piezoelectric ceramic tube.

According to an embodiment of the present invention, the behavior stage unit may include a macro movement stage unit for elevating the probe at intervals of sub-micro units to millimeters on the surface of the substrate. The macro moving stage unit includes a linear motor that contracts and expands in the frame, and a linear guide that restricts movement of the scan head unit and the accessible variable stage unit in a direction perpendicular to the substrate according to the contraction and expansion of the linear motor. can do. The frame may include a vertical frame in which the linear guide is formed vertically on the table outside the substrate stage, and a horizontal frame fixing the stepping motor in the vertical frame.

An atomic force microscope according to another embodiment of the present invention includes a table; A substrate stage unit supporting the substrate and moving horizontally on the table; A scan head portion including a piezoelectric ceramic tube for scanning an upper portion of the substrate facing the substrate stage portion with a probe and a cantilever; A frame supporting the scan head portion on the table; A macro moving stage part which detaches the scan head part from the frame and moves the scan head part in a direction perpendicular to the substrate when the probe is replaced in the scan head part; And connecting the behavior stage part and the scan head part, and approaching the probe to the surface of the substrate during scanning of the scan head part and from the surface of the substrate during horizontal movement of the substrate by the substrate stage part. And a micro moving stage having a stacked piezoelectric ceramic bar spaced apart from each other.

As described above, according to the problem solving means of the present invention, the variable access stage portion may be disposed between the scan head portion and the behavior stage portion. The variable access stage unit may approach the probe to the surface of the substrate during scanning of the scan head unit. In addition, the variable access stage unit may space the probe from the surface of the substrate to prevent damage to the probe due to the step of the substrate surface during the horizontal movement of the substrate. Therefore, when the approach variable stage part wants to randomly scan a plurality of measurement positions on a large area substrate with the scan head part, there is an effect that enables high-speed measurement.

1 is a view schematically showing an atomic force microscope according to an embodiment of the present invention.
Figure 2 is a perspective view showing in more detail the atomic microscope of Figure 1;
3 is an exploded perspective view illustrating the scan head portion and the fine movement stage portion and the behavior stage portion in FIG. 2.
4 is a perspective view of the scanner of FIG. 3;
FIG. 5 is a perspective view illustrating the fine motion stage unit and the behavior stage unit of FIG. 3. FIG.
FIG. 6 is a perspective view illustrating the stacked piezoelectric ceramic bar of FIG. 5. FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Advantages and features of the present invention, and methods of achieving the same will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in different forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the invention to those skilled in the art, and the invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. As used herein, the terms 'comprises' and / or 'comprising' mean that the stated element, step, operation and / or element does not imply the presence of one or more other elements, steps, operations and / Or additions. In addition, since they are in accordance with the preferred embodiment, the reference numerals presented in the order of description are not necessarily limited to the order.

1 is a view schematically showing an atomic force microscope according to an embodiment of the present invention.

Referring to FIG. 1, an atomic force microscope according to an exemplary embodiment of the present invention includes a scan head unit 60 scanning a substrate 30 on a substrate stage 20 of a table 10, and the scan head unit 60. It may include a micro-moving stage (70) for approaching the surface of the substrate (62) at a high speed (approach), or at a high speed (lifting). The fine movement stage 70 contacts / closes the probe 62 to the surface of the substrate 30 when scanning the substrate 30 of the scan head 60, and moves the substrate 30 horizontally of the substrate stage 20. The probe 62 and the cantilever 64 may be spaced apart from the substrate 30 at the time.

Accordingly, the atomic force microscope according to the embodiment of the present invention includes a microscopic stage portion 70 for contacting or spaced apart from the probe 62 of the scan head portion 60 on the surface of the substrate 30. 30 can be scanned at high speed randomly.

The substrate stage unit 20 may move the substrate 30 horizontally. The probe 62 may be spaced apart from the surface of the substrate 30 by a predetermined distance or more by the microscopic stage 70 when the substrate 30 is horizontally moved. Because of this, the probe 62 can prevent collisions from patterns (not shown) on the substrate 30 or steps (not shown) on the surface of the substrate 30.

The surface of the substrate 30 may be measured when the probe 62 and the cantilever 64 of the scan head 60 are close to the substrate 30. The scan head 60 may scan the probe 62 and the cantilever 64 on the surface of the substrate 30. The probe 62 may be in contact with the surface of the substrate 30 or may be scanned in a non-contact manner. The probe 62 may be formed to protrude sharply from the end of the cantilever 64. The probe 62 may be formed in a pyramid, tetrahedron, or cone shape. The contact probe 62 may be formed to have a rounded tip than the non-contact probe 62. For example, the probe 62 may be manufactured by a micro-machining method and then connected to the cantilever 64.

The cantilever 64 may be bent as the probe 62 moves up and down. The cantilever 64 may have a modulus of elasticity lower than the bond modulus (for example, 10 N / m) between atoms of the substrate 30. The cantilever 64 to which the contact probe 62 is connected may have a smaller modulus of elasticity than the cantilever 64 to which the non-contact probe 62 is connected. In addition, the cantilever 64 to which the non-contact probe 62 is connected may be quickly vibrated at a resonance frequency of about several tens of kHz to several hundreds of kHz. Therefore, the cantilever 64 to which the non-contact probe 62 is connected may have higher horizontal resolution and stability as the elastic modulus is larger. For example, the cantilever 64 may be formed to be horizontal or inclined with the substrate 30 in a triangular shape. The cantilever 64 may be formed of single crystal silicon, a silicon nitride film, or the like.

The scan head portion 60 may include a scanner 66 that scans with the probe 62 and cantilever 64 along the surface of the substrate 30. The scanner 66 may be connected to the frame 40 on the table 10 through the microscopic moving stage 70 and the macro-moving stage 50. The behavior stage 50 may raise the scan head 60 and the fine stage 70 in a direction perpendicular to the substrate 30 when the new probe 62 and the cantilever 64 are replaced. Thus, the behavior stage unit 50 may be a component replacement stage unit. The scan head portion 60 and the fine movement stage portion 70 and the movement stage portion 50 are supported by the frame 40, which will be described in more detail with reference to FIGS. 2 to 6.

FIG. 2 is a perspective view showing the atomic microscope of FIG. 1 in more detail, and is an exploded perspective view showing the scan head portion and the fine moving stage portion and the behavior stage portion of FIG. 2. 4 is a perspective view illustrating the scanner of FIG. 3, FIG. 5 is a perspective view illustrating the fine motion stage unit and the behavior stage unit of FIG. 3, and FIG. 6 is a perspective view illustrating the stack piezoelectric ceramic bar of FIG. 5.

2 and 3, the table 10 may fix the substrate stage 20 and the frame 40. The substrate stage unit 20 may move the substrate 30 horizontally in a plane formed by the X and Y axes. The frame 40 may include a column frame 42 formed in a direction perpendicular to the table 10 and a plate frame 44 extending from the column frame 42 to the upper portion of the substrate 30. The column frame 42 may fix the plate frame 44 on the table 10. The plate frame 44 may support the behavior stage unit 50. The movement stage unit 50 may support the fine movement stage unit 70 and the scan head unit 60. The behavior stage unit 50 may be supported by the column frame 42 and the plate frame 44. The behavior stage unit 50 may be moved up and down along the column frame 42 in a direction perpendicular to the substrate 30.

The behavior stage unit 50 may be moved vertically along the linear guide 56 fastened to the column frame 42 by the driving of the linear motor 52 fixed to the plate frame 44. The linear motor 52 may be disposed between the plate frame 44 and the scan head portion 60. The linear motor 52 may generate a force for moving the shaft 54 in a straight line according to a current applied from the outside. The linear guide 56 may assist the vertical movement of the scan head unit 60 and the fine moving stage unit 70.

For example, the movement stage unit 50 may vertically move the scan head unit 60 and the fine movement stage unit 70 in a range of about 10 mm. The behavior stage unit 50 may be a macro moving stage unit for elevating the probe 62 on the surface of the substrate 30 at intervals from sub-micro units to millimeters. As described above, the behavior stage 50 can be moved vertically when the cantilever 64 and the probe 62 are replaced in the scanner 66 of the scan head 60. The cantilever 64 and the probe 62 may be replaced periodically as the cumulative usage time elapses, and may be replaced in an emergency due to breakage.

The scan head unit 60 may include an optical system 68 for detecting a rising / lowering position of the probe 62 and the cantilever 64. The optical system 68 can detect the rising / lowering position change of the probe 62 by an optical method. The optical system 68 generates a laser light 65 and emits a laser source 67 that irradiates the cantilever 64 on the probe 62, and a light that detects the laser light 65 reflected by the cantilever 64. Sensor 69 may be included. The laser source 67 may pass through the inside of the scanner 66 to irradiate the laser light 65 to the end of the cantilever 64. The optical sensor 69 may detect the laser light 65 reflected at the end of the cantilever 64. The optical system 68 can continuously detect the rising / lowering position change of the probe 62 corresponding to the change in the reflection angle of the laser light 65.

The scanner 66 can precisely move the cantilever 64 and the probe 62 horizontally and vertically. For example, the scanner 66 may include the piezoelectric ceramic tube 80 of FIG. 4. Piezoelectrics may be contracted or expanded by a power supply voltage applied from the outside. The piezoelectric ceramic tube 80 may have a small mass while passing the laser light 65 of the optical system 68 therein. The piezoelectric ceramic tube 80 is small in mass so that the scanner 66 can be quickly scanned at the measurement position.

Referring to FIG. 4, the scanner 66 has a surface of the substrate 30 parallel to a plane formed by the X and Y axes according to voltages applied to the ± X power terminals 86 and the ± Y power terminals 88. The probe 62 and the cantilever 64 may be scanned along the same. Here, the ± X power terminals 86 may be connected to the X electrodes 82, and the ± Y power terminals 88 may be connected to the Y electrodes 84. The scanner 66 may be driven by a raster. The scanner 66 may scan all the two-dimensional areas by scanning the first line and then moving back and moving one space in the vertical direction to repeatedly perform the second, third, and nth lines.

In addition, the scanner 66 may be vibrated in the Z-axis direction according to the height of the patterns formed on the surface of the substrate 30. The scanner 66 expands and contracts by the first variable height ΔL1 from the existing first height L1 when the same voltage is applied to the ± X power terminals 86 and the ± Y power terminals 88. Can be. For example, the scanner 66 of the piezoelectric ceramic tube 80 may be contracted and expanded to within ± 5 μm.

In particular, the piezoelectric ceramic tube 80 is small in mass, which allows the scanner 66 to enable fast scanning at the measurement position. In the piezoelectric ceramic tube 80, the vibration frequency in the Z-axis direction of the scanner 66 may be represented by Equation 1.

[Equation 1]

Where 2π is the modulus of elasticity and m is the mass of the scanner 66. The Z-direction vibration frequency of the scanner 66 is inversely proportional to the mass. Therefore, the scanner 66 can quickly scan the surface of the substrate 30 when the mass is small. The scanner 66 of the piezoelectric ceramic tube 80 may move the probe 62 vertically to within ± 5 μm from the surface of the substrate 30. The scanner 66 may damage the probe 62 when scanning the surface of the substrate 30 having a step of ± 5 μm or more. Therefore, the scanner 66 may be spaced apart from the surface of the substrate 30 in the vertical direction by the fine moving stage 70 during the horizontal movement of the substrate 30.

3 and 5, the fine moving stage 70 may move the scan head 60 to the surface of the substrate 30 or may be spaced apart from the surface of the substrate 30 by a predetermined distance or more. The fine movement stage unit 70 may be a contact variable stage unit for moving the probe 62 of the scan head unit 60 to a height of about ± 100 μm from the surface of the substrate 30. In addition, the micro-movement stage unit 70 may be a micro-movement stage unit for elevating the probe 62 at intervals from nanometer units to sub-micro units on the surface of the substrate 30.

The fine motion stage unit 70 may be connected to the behavior stage unit 50 by at least one leaf spring 72. The leaf spring 72 may include a plate contact surface 76 between the fine motion stage portion 70 and the behavior stage portion 50. The leaf spring 72 may move the fine motion stage 70 in a direction perpendicular to the substrate 30 by contraction and expansion of the stacked piezoelectric ceramic bar 74. The stacked piezoelectric ceramic bars 74 may be supported inside the behavior stage 50.

Referring to FIG. 6, the stacked piezoelectric ceramic bar 74 may include a plurality of piezoelectric plates 73 stacked with each other, and stack electrodes 75 between the piezoelectric plates 73. The stack electrodes 75 may be alternately connected between the ground terminal and the power supply terminal 78 between the plurality of front plates 73. The stacked piezoelectric ceramic bars 74 may be shrunk or expanded in proportion to the number of piezoelectric plates 73. The stacked piezoelectric ceramic bars 74 may be expanded or contracted by a distance of the second variable height ΔL2 from the second height L2. Stacked piezoelectric ceramic bar 74 may have more mass and length than piezoelectric ceramic tube 80 of scanner 66. Stacked piezoelectric ceramic bar 74 may be shrunk or expanded at a significantly longer distance than piezoelectric ceramic tube 80 of scanner 66. In addition, the stacked piezoelectric ceramic bars 74 can be quickly shrunk or expanded. The power supply voltage input to the power supply terminal of the stacked piezoelectric ceramic bar 74 may be interrupted by a signal output from the optical system 68 that detects the rising and falling positions of the probe 62 and the cantilever 64.

Therefore, the atomic force microscope according to the embodiment of the present invention is used at any measurement position of the large-area substrate 30 by using the microscopic stage portion 70 including the stacked piezoelectric ceramic bars 74 that contract and expand in a linear direction. Scanning at high speed.

For example, the fine stage 70 may access the probe 62 having a height of about 100 μm from the surface of the substrate 30 to the surface of the substrate 30 within about 1 second. The scan head portion 60 can scan the surface of the substrate 30 in an area of about 1 cm ² within about 3 seconds. Again, the fine stage 70 may separate the probe 62 within about 1 second from the surface of the substrate 30 to a height of about 100 μm. Accordingly, the atomic force microscope according to the embodiment of the present invention can measure the surface of the substrate 30 within about 5 seconds at any measurement position on the large area substrate 30.

As a result, the atomic force microscope according to the embodiment of the present invention uses high-speed stage portions 70 that move or separate the scan head portion 60 to the substrate 30 at high speed. Can be scanned by

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood. It is therefore to be understood that the above-described embodiments are illustrative and non-restrictive in every respect.

10: Table 20: substrate stage portion
30: substrate 40: frame
50: behavior stage portion 60: scan head portion
70: fine movement stage part

Claims (12)

A substrate stage unit supporting the substrate and moving horizontally;
A scan head unit scanning an upper portion of the substrate facing the substrate stage unit with a probe and a cantilever;
A frame supporting the scan head portion;
A movement stage portion which detaches the scan head portion from the frame and moves the scan head portion in a direction perpendicular to the substrate when the probe and the cantilever are replaced in the scan head portion; And
The probe is connected to the behavior stage unit and the scan head unit, and the probe approaches the surface of the substrate when scanning the scan head unit, and the probe is removed from the surface of the substrate during horizontal movement of the substrate by the substrate stage unit. An atomic force microscope comprising a variable access stage portion spaced apart. The method of claim 1,
And the access variable stage unit comprises a micro moving stage unit for raising and lowering the probe at intervals from nanometer units to sub-micro units on the substrate surface. The method of claim 2,
And the micro moving stage portion comprises a stacked piezoelectric ceramic bar. The method of claim 3, wherein
The stacked piezoelectric ceramic bar includes a plurality of piezoelectric plates stacked in one direction, stack electrodes formed between the plurality of piezoelectric plates, a ground terminal and a power terminal connected to the stack electrodes, respectively. The method of claim 3, wherein
The micro-movement stage unit further comprises a leaf spring which is raised and lowered by the stacked piezoelectric ceramic bar. The method of claim 4, wherein
And the leaf spring includes a plate contact surface coupled to the micro moving stage portion and the behavior stage portion. The method of claim 1,
The scanning head portion atomic microscope including a scanner. The method of claim 7, wherein
The scanner comprises an atomic force microscope comprising a piezoelectric ceramic tube. The method of claim 1,
And the behavior stage portion comprises a macro movement stage portion for raising and lowering the probe at intervals from the sub-micro to millimeter units on the surface of the substrate. The method of claim 9,
The macro moving stage unit includes a linear motor that contracts and expands in the frame, and a linear guide that restricts movement of the scan head unit and the accessible variable stage unit in a direction perpendicular to the substrate according to the contraction and expansion of the linear motor. Atomic Force Microscope. The method of claim 10,
The frame includes a vertical frame in which the linear guide is formed vertically on the table outside the substrate stage, and a horizontal frame fixing the stepping motor in the vertical frame. table;
A substrate stage unit supporting the substrate and moving horizontally on the table;
A scan head portion including a piezoelectric ceramic tube for scanning an upper portion of the substrate facing the substrate stage portion with a probe and a cantilever;
A frame supporting the scan head portion on the table;
A macro moving stage part which detaches the scan head part from the frame and moves the scan head part in a direction perpendicular to the substrate when the probe is replaced in the scan head part; And
The probe is connected to the behavior stage unit and the scan head unit, and the probe approaches the surface of the substrate when scanning the scan head unit, and the probe is removed from the surface of the substrate during horizontal movement of the substrate by the substrate stage unit. An atomic force microscope comprising a micro moving stage with spaced apart piezoelectric ceramic bars.

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