A method and a measurement system for measuring three-dimensional atomic coordinates at the sub-nanometer scale

Abstract

The present invention provides a method and a measurement system for measuring three-dimensional atomic coordinates at the sub-nanometer scale. This method can achieve three-dimensional measurements with atomic precision, providing a more accurate measurement method and system for the development of nanotechnology. The invention uses the periodic atomic lattice arrangement pattern of lattice materials as a measurement scale. Its main components include: an atomic lattice measurement scale composed of a reference lattice material and its detection system, actuators for three axes, and a probe scanning module for detecting samples. Each nano-actuator on each axis is equipped with a counter. When the axis moves, the actuator drives the counter to count the atomic lattice, and then the result is used to feedback the movement distance of the axis. This system provides precise three-dimensional measurement functions for special application requirements from the sub-nanometer scale to the nanometer scale, achieving macroscopic measurement results with atomic lattice precision.

Description

Technical Field

[0001] The present invention belongs to the technical field of nano measurement, and particularly relates to a three-dimensional atomic coordinate measurement method and measurement system at the sub-nanometer scale. Background Art

[0002] Nano measurement technology is the prerequisite for the development of nano manufacturing technology. With the continuous development of nano manufacturing, especially nano lithography technology, the requirements for nano measurement technology are getting higher and higher, especially for measurements at the sub-nanometer scale. Facing such challenges, accurate measurement at the sub-nanometer scale has become the development direction in the field of metrology, and precise sub-nanometer measurement technology will open a new door for nano technology and its wide applications.

[0003] Currently, scanning electron microscopes (SEM), atomic force microscopes (AFM), and scanning tunneling microscopes (STM) are the main tools for nano-scale measurements, but these technologies all have their own limitations. These technologies have certain requirements for the samples to be measured, it is difficult to achieve large-area measurements, and the equipment cost is high. Among them, SEM can only measure two-dimensional information on the surface of materials, STM can only measure conductive materials, although AFM is not limited by the electrical properties of materials and can also obtain three-dimensional information on the surface of materials, it still cannot achieve large-area measurements. None of the above technologies can achieve atomic precision measurement.

[0004] For natural crystal materials, they have a dense atomic structure distribution and scale distance. For example, monolayer graphene is a two-dimensional material with a thickness of only one carbon atom, composed of carbon atoms arranged in a hexagonal honeycomb lattice, and its lattice constant a is only c is (001) plane mica has a lattice a of b is The lattice constant a of single crystal quartz is c is Such a precise lattice structure is the natural scale of metrology technology. Making good use of this point will break through the limits of existing measurement technologies and achieve measurements at the sub-nanometer scale. In 2006, a two-dimensional (2D) measurement method based on a reference pattern was proposed (Zuobin Wang, Shizhong Su, Yury Konstantinovich Verevkin, and Sergej Fatikow. "Reference pattern-based 2D measurement with nanoresolution", Proc. SPIE 6376, Optomechatronic Micro / Nano Devices and Components II, 63760M (17 October 2006)). In this method, a patterned periodic structure is obtained using four-beam laser interference lithography technology, and a 2D measurement technique is proposed based on this as a reference. The nanoresolution of the measurement is achieved by matching the reference pattern technology and counting the features of the structure. However, limited by laser interference technology, this technique can only achieve nano-scale measurements of two-dimensional structures, and the measurement accuracy also depends on the accuracy of the structure after laser interference processing. Summary of the Invention

[0005] To solve the problem of difficult three-dimensional measurement with sub-nanometer accuracy, since crystal materials have a dense structure and precise lattice scale, the present invention makes use of this natural advantage of crystal materials and uses the natural lattice structure as a scale to propose a three-dimensional atomic coordinate measurement method and measurement system at the sub-nanometer scale, aiming to achieve a macroscopic three-dimensional measurement technology with sub-nanometer accuracy. The present invention is used to solve the problem of difficult sub-nanometer scale measurement and studies a novel sensing and detection technology. This method provides precise three-dimensional measurement functions for special application requirements from the sub-nanometer level to the nanometer level and achieves macroscopic measurement results with atomic accuracy.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A three-dimensional atomic coordinate measurement method at the sub-nanometer scale, taking a lattice material as a reference, using the natural atomic lattice arrangement geometric distance of its lattice structure as a lattice measurement scale, identifying the atomic lattice arrangement pattern of its lattice structure and counting the atomic lattice as a lattice measurement scale, combining the three lattice measurement scales according to the X, Y, and Z axes, establishing a three-dimensional coordinate system with the atomic lattice distance of the material as the measurement unit, and forming a three-axis lattice measurement scale; the probe scanning module forms a three-axis scanning trajectory with the three lattice measurement scales as axes, and the movement distance of the probe scanning module is counted in units of the atomic lattice on this axis. After the three axes are calibrated respectively, the system drives the lattice measurement scales of the three axes respectively and uses the probe tip in the probe scanning module to sense and position the sample to be measured, mark the morphological coordinate values of the sample to be measured in the three-dimensional coordinate system, scan the sample to be measured, and mark the parameter positions of the surface morphology of the sample to be measured in the three-dimensional coordinate system in the way of atomic lattice counting. Finally, a three-dimensional morphological image of the sample to be measured is obtained in the three-dimensional coordinate system, and its resolution is at the atomic lattice scale. When the temperature, humidity, air pressure, and vibration conditions are stable, the lattice scale is a constant, realizing macroscopic measurement at the sub-nanometer scale. By inputting the corresponding lattice constant value of the lattice material, the specific morphological parameters of the sample to be measured can be further obtained.

[0008] Further, the lattice material is a two-dimensional lattice structure with a single atomic thickness, including a conductor lattice material, a semiconductor lattice material, or an insulator lattice material.

[0009] Further, the lattice measurement scale includes a two-dimensional lattice structure and an induction system for identifying the atomic lattice arrangement pattern and counting the atomic lattice. The induction system realizes the identification and counting of the atomic lattice through the detection and scanning of the microscopic force in the probe tapping or contact mode, or through the tunneling current detection method.

[0010] Further, the probe scanning module includes a scanning probe and a scanning motion sensor. The scanning probe is connected to the scanning motion sensor, and the scanning motion sensor is linked with the three-axis lattice measurement scale. The movement distance unit of the scanning motion sensor is the atomic lattice, and each lattice measurement scale records the movement trajectory of the scanning motion sensor in real time.

[0011] Further, the atomic lattice size is based on the atomic lattice of the lattice material.

[0012] Further, the lattice measurement scale is linked with a probe scanning module separately. After establishing a two-dimensional coordinate system through the identification of the atomic lattice arrangement pattern of the two-dimensional lattice structure, it is used for two-dimensional information measurement.

[0013] Furthermore, for the recognition of the atomic lattice arrangement pattern of the two-dimensional lattice structure, a relevant pattern recognition method is adopted to recognize and calibrate the atomic lattice arrangement pattern of the two-dimensional lattice structure.

[0014] Furthermore, the lattice measurement scale is used independently and applied to nano-lithography, sub-nano-lithography in integrated circuits, or other nano-imaging, nano-manipulation, nano-assembly, and nano-fabrication systems.

[0015] The present invention also provides a measurement system applying the three-dimensional atomic coordinate measurement method at the sub-nano scale, including a three-axis lattice measurement platform, a probe scanning module, a sample stage, a laser module, an optoelectronic signal processing module, and an anti-vibration platform; the three-axis lattice measurement platform is a displacement platform for placing lattice measurement scales along the X, Y, and Z axes, the probe scanning module holds a scanning probe, the sample stage is a three-axis micro-meter displacement sample stage, the laser module emits laser light to the cantilever of the scanning probe and is reflected to the optoelectronic signal processing module for processing, the anti-vibration platform prevents the platform from vibrating to ensure the measurement accuracy, the main control computer controls the three-axis lattice measurement platform for positioning and scanning, and simultaneously records the data of the optoelectronic signal processing module, and images with the data of the morphology coordinate values of the sample to be measured marked in the three-dimensional coordinate system, where the lattice materials of the lattice measurement scales are the same, or two or three different ones.

[0016] After the present invention adopts the above technical solutions, the following main advantages are obtained:

[0017] (1) Compared with the traditional method, the method involved in the present invention can achieve large-area measurement with sub-nano accuracy;

[0018] (2) The device involved in the present invention has the advantage of flexible use and can be applied to nano-lithography, sub-nano-lithography in integrated circuits, or other nano-imaging, nano-manipulation, nano-assembly, and nano-fabrication systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is the schematic diagram of the present invention: 1 - lattice material, 2 - recognition of atomic lattice arrangement pattern and atomic lattice counting, 3 - three-dimensional coordinate system, 4 - tip positioning and scanning of the scanning probe, 5 - sample to be measured, 6 - three-dimensional morphology imaging.

[0020] Figure 2 It is the system schematic diagram of the present invention: 7 - three-axis lattice measurement platform, 8 - probe scanning module, 9 - sample stage, 10 - laser module, 11 - optoelectronic signal processing module, 12 - anti-vibration platform.

[0021] Figure 3 It is the schematic diagram of measuring nano-particles with the graphene lattice material as the three-axis lattice measurement scale in the present invention.

[0022] Figure 4 It is a mica lattice structure.

[0023] Figure 5 It is a graphene lattice structure. Specific embodiments

[0024] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] As Figure 1 and Figure 2 shown, the present invention provides a three-dimensional atomic coordinate measurement method and measurement system at the sub-nanometer scale.

[0026] The three-dimensional atomic coordinate measurement method of the present invention uses the lattice material 1 as a reference, identifies the atomic lattice arrangement pattern of its lattice structure and counts the atomic lattice 2 to obtain a lattice measurement scale. The three lattice measurement scales are combined according to the X, Y, and Z axes to establish a three-dimensional coordinate system 3 with atoms as the measurement unit, forming a three-axis lattice measurement scale. The probe scanning module 8 forms a three-axis scanning trajectory with the three lattice measurement scales as the axes. The moving distance of the probe scanning module 8 is counted in units of the atoms on the lattice measurement scale of the axis. The tip of the probe in the probe scanning module 8 is used to perform scanning probe tip positioning and scanning 4 on the sample to be measured 5, mark the morphological coordinate values of the sample to be measured 5 in the three-dimensional coordinate system 3. After calibrating the three axes respectively, the sample to be measured 5 is scanned, and the parameter positions of the surface morphology of the sample to be measured 5 are marked in the three-dimensional coordinate system 3 in the way of atomic lattice counting. Finally, a three-dimensional morphological image 6 of the sample to be measured is obtained in the three-dimensional coordinate system 3, and its resolution is the atomic lattice scale. Under a controllable environment (temperature, humidity, air pressure, vibration, etc.), the lattice scale is a constant, realizing macroscopic measurement at the sub-nanometer scale. By inputting the corresponding lattice constant value of the lattice material, the specific parameters of the sample to be measured can be further obtained. Among them, the three-dimensional coordinate system 3 can be a spherical coordinate system or a rectangular coordinate system.

[0027] As Figure 2As shown, the measurement system of the present invention is used for a three-dimensional atomic coordinate measurement method at the sub-nanometer scale, which includes a three-axis lattice measurement platform 7, a probe scanning module 8, a sample stage 9, a laser module 10, an optoelectronic signal processing module 11, and a vibration isolation platform 12. The three-axis lattice measurement platform 7 is a displacement platform with lattice measurement scales placed along the X, Y, and Z axes. The probe scanning module 8 holds a scanning probe. The sample stage 9 is a three-axis micro-meter displacement sample stage. The laser module 10 emits laser light that hits the cantilever of the scanning probe and is reflected to the optoelectronic signal processing module 11 for processing. The vibration isolation platform 12 can prevent the platform from vibrating to ensure the measurement accuracy. The main control computer controls the three-axis lattice measurement platform 7 for positioning and scanning, and at the same time records the data of the optoelectronic signal processing module 11, and uses the data of the morphological coordinate values of the sample to be measured marked in the three-dimensional coordinate system for imaging. Among them, the lattice materials of the three-axis lattice measurement platform 7 can be the same, or two or three different ones.

[0028] The lattice material should be a two-dimensional lattice structure with a single atomic thickness, which can be a conductor lattice material, a semiconductor lattice material, and an insulator lattice material, such as the lattice material of the Au(111) plane, single-layer graphene, mica, quartz crystal, etc.

[0029] A lattice measurement scale includes a two-dimensional lattice structure and an induction system for identifying and counting the atomic lattice arrangement pattern. The identification and counting of atoms by this induction system can be achieved through the detection and scanning of the microscopic force in the probe tapping / contact mode, or through the detection of the tunneling current magnitude. The specific method for identifying the atomic lattice arrangement pattern of the lattice structure and counting the atomic lattice is mainly based on the conductivity of the reference lattice material. For example, if the lattice material is a conductive material such as graphene or metal, both the probe tapping / contact mode microscopic force and tunneling current detection can meet the requirements. If the lattice material is a mica or quartz-like lattice material, only the microscopic force detection and scanning method in the probe tapping / contact mode can be used.

[0030] The probe scanning module 8 holds a scanning probe. The scanning probe is connected to a scanning motion sensor, and the scanning motion sensor is linked with the three-axis lattice measurement platform 7. The movement distance unit of the scanning motion sensor is an atom, and each lattice measurement scale can record the movement trajectory of the scanning motion sensor in real time. In addition, the scale of the scanning probe is 2 nanometers. The probe scanning module 8 can not only collect the morphological information of the sample to be measured, but also collect other physical property information of the sample to be measured, such as mechanical properties, electrical properties, magnetic properties, acoustic properties, etc.

[0031] Multiple three-axis lattice measurement platforms 7 based on lattice materials can be used together, or can be individually linked with a probe scanning module. After establishing a two-dimensional coordinate system through the identification of the atomic lattice arrangement pattern of the two-dimensional lattice structure, it can be used for two-dimensional measurement.

[0032] In atomic lattice counting, the size of the atomic lattice is based on the atomic lattice of the lattice material.

[0033] For the recognition of the atomic lattice arrangement pattern of a two-dimensional lattice structure, relevant pattern recognition methods are adopted to recognize and calibrate the atomic lattice arrangement pattern of the two-dimensional lattice structure.

[0034] The lattice measurement scale proposed in the present invention based on the lattice material can also be used independently and applied to nano-lithography, sub-nano-lithography in integrated circuits, or other nano-imaging, nano-manipulation, nano-assembly, and nano-fabrication systems.

[0035] Example 1:

[0036] Based on the mica lattice material, after recognizing the atomic lattice arrangement pattern of its lattice structure and performing atomic lattice counting, it is used as the lattice measurement scale. The structure of the mica lattice is obtained by using the above probe scanning method. As Figure 4 shown, the image resolution is 256×256. The mica lattice structure is scanned in tapping mode, and the unit distances in each direction of the structure are 102 pm, 74.2 pm, 91.8 pm, and 215 pm respectively, which are used as the lattice measurement scale. Relevant pattern recognition methods are adopted to recognize and calibrate the atomic lattice arrangement pattern of the two-dimensional lattice structure to obtain a spherical coordinate system. Figure 3 As shown. Three identical mica lattice measurement scales are combined according to the X, Y, and Z axes to establish a three-dimensional coordinate system 3 with atoms as the measurement unit. Combined with an actuator, it is packaged into a three-axis lattice measurement platform 7. The probe scanning module 8 forms a three-axis scanning trajectory with the three lattice measurement scales as the axes. The moving distance of the probe scanning module 8 is counted in units of atoms of the lattice measurement scale on this axis. The nano-particle to be measured is placed on the sample stage 9. The computer controls the sample stage 9 to move the sample to an appropriate position. The computer uses the scan controller to position the scanning probe of the probe scanning module 8 and calibrate the three-axis lattice measurement scale, and then performs scanning. The probe scanning module 8 is linked with the three-axis lattice measurement platform 7 to record the scanning motion trajectory in real time. The induction system in each lattice measurement scale records the position of the nano-particle in the three-dimensional coordinate system by means of atomic lattice counting. The optoelectronic signal processing module 11 transmits the recorded information to the computer to obtain a three-dimensional morphology image 6 of the nano-particle in units of atoms. The mica lattice parameters obtained by the above probe scanning method are input into the three-dimensional image to obtain the specific morphology parameters of the nano-particle.

[0037] Example 2:

[0038] Taking a single-layer graphene lattice material as a reference, after identifying the atomic lattice arrangement pattern of its lattice structure and counting the atomic lattice, it is used as a lattice measurement scale. Adopting relevant pattern recognition methods to identify and calibrate the atomic lattice arrangement pattern of the two-dimensional lattice structure to obtain a spherical coordinate system, Figure 3 as shown. The graphene lattice structure scanned by the above probe scanning method is as shown in Figure 5 as shown. It can be clearly seen from the figure that it is composed of carbon atoms arranged in a hexagonal honeycomb lattice. The scanning range is 10nm×10nm, serving as a three-axis lattice measurement platform 7. Three identical graphene lattice measurement scales are combined according to the X, Y, and Z axes to establish a three-dimensional coordinate system 3 with atoms as the measurement unit. Combined with an actuator, it is packaged into a three-axis lattice measurement platform 7. The probe scanning module 8 forms a three-axis scanning trajectory with the three lattice measurement scales as axes. The moving distance of the probe scanning module 8 is counted in units of atoms on the lattice measurement scale of this axis. Place the nanoparticle to be measured on the sample stage 9. The computer controls the sample stage 9 to move the sample to an appropriate position. The computer controls the three-axis lattice measurement platform 7 to position the scanning probe of the probe scanning module 8 and calibrate the three-axis lattice measurement scale, and then conducts scanning. The probe scanning module 8 is linked with the three-axis lattice measurement platform 7 to record the scanning movement trajectory in real time. The induction system in each lattice measurement platform records the position of the nanoparticle in the three-dimensional coordinate system by counting the atomic lattice. The optoelectronic signal processing module 11 transmits the recorded information to the computer to obtain a three-dimensional morphology image 6 of the nanoparticle in units of atoms. Given that the lattice structure of graphene is composed of carbon atoms arranged in a hexagonal honeycomb lattice, its lattice constant a is c is Input these lattice constants into the three-dimensional image to obtain specific morphology parameters of the nanoparticle.

[0039] The above has introduced in detail a three-dimensional atomic coordinate measurement method and measurement system provided by the present invention. Providing the above examples is only to help understand the method of the present invention, rather than to limit the scope of the present invention. It should be noted that for those of ordinary skill in the art of this technology, the scope of the present invention is defined by the appended claims. Without departing from the spirit and principle of the present invention, all kinds of equivalent substitutions, modifications, improvements, and decorations should be covered within the scope of the present invention.

Claims

1. A three-dimensional atomic coordinate measurement method at the sub-nanometer scale, characterized in that: Based on the lattice material, using the natural atomic lattice arrangement geometric distance of its lattice structure as the lattice measurement scale, after identifying the atomic lattice arrangement pattern and counting the atomic lattice of its lattice structure, the three lattice measurement scales are combined according to the X, Y, and Z axes to establish a three-dimensional coordinate system with the atomic lattice distance of the material as the measurement unit, constituting a three-axis lattice measurement scale; the probe scanning module forms a three-axis scanning trajectory with the three lattice measurement scales as axes, and the moving distance of the probe scanning module is counted in the unit of the atomic lattice distance of the material on the axis. After calibrating the three axes respectively, the lattice measurement scales of the three axes are driven respectively, and the scanning probe tip in the probe scanning module is used to sense and position the sample to be measured, mark the topography coordinate values of the sample to be measured in the three-dimensional coordinate system, scan the sample to be measured, and mark the parameter positions of the surface topography of the sample to be measured in the three-dimensional coordinate system in the way of counting the atomic lattice distance of the material. Finally, a three-dimensional topography image of the sample to be measured is obtained in the three-dimensional coordinate system, and its resolution is the atomic lattice distance of the material. When the temperature, humidity, air pressure, and vibration conditions are stable, the atomic lattice distance of the material is a constant, realizing macroscopic measurement at the sub-nanometer scale. By inputting the corresponding lattice constant value of the lattice material, the specific topography parameters of the sample to be measured can be further obtained.

2. The three-dimensional atomic coordinate measurement method at the sub-nanometer scale according to claim 1, characterized in that: The lattice material is a two-dimensional lattice structure with a single atomic thickness, including a conductor lattice material, a semiconductor lattice material, or an insulator lattice material.

3. The three-dimensional atomic coordinate measurement method at the sub-nanometer scale according to claim 1, characterized in that: The lattice measurement scale includes a two-dimensional lattice structure and an induction system for identifying the atomic lattice arrangement pattern and counting the atomic lattice. The identification and counting of the atomic lattice by the induction system are realized through the detection and scanning of the microscopic force in the probe tapping or contact mode, or through the tunneling current detection method.

4. The three-dimensional atomic coordinate measurement method at the sub-nanometer scale according to claim 3, characterized in that: The probe scanning module includes a scanning probe and a scanning motion sensor. The scanning probe is connected to the scanning motion sensor, and the scanning motion sensor is linked with the three-axis lattice measurement scale. The moving distance unit of the scanning motion sensor is the atomic lattice distance of the material, and each lattice measurement scale records the moving trajectory of the scanning motion sensor in real time.

5. The three-dimensional atomic coordinate measurement method at the sub-nanometer scale according to claim 1, characterized in that: The atomic lattice size is based on the atomic lattice of the lattice material.

6. The three-dimensional atomic coordinate measurement method at the sub-nanometer scale according to claim 3, characterized in that: The lattice measurement scale is individually linked with a probe scanning module. After establishing a two-dimensional coordinate system by identifying the atomic lattice arrangement pattern of the two-dimensional lattice structure, it is used for two-dimensional information measurement.

7. The three-dimensional atomic coordinate measurement method at the sub-nanometer scale according to claim 3, characterized in that: The identification of the atomic lattice arrangement pattern of the two-dimensional lattice structure adopts the method of correlation pattern recognition to identify and calibrate the atomic lattice arrangement pattern of the two-dimensional lattice structure.

8. The three-dimensional atomic coordinate measurement method at the sub-nanometer scale according to claim 3, characterized in that: The lattice measurement scale is used independently and applied to nano-lithography, sub-nano lithography in integrated circuits, or other nano-imaging, nano-manipulation, nano-assembly, and nano-fabrication systems.

9. A measurement system for implementing the three-dimensional atomic coordinate measurement method at the sub-nanometer scale according to any one of claims 1-8, characterized in that: It includes a three-axis lattice measurement platform (7), a probe scanning module (8), a sample stage (9), a laser module (10), an optoelectronic signal processing module (11) and a vibration isolation platform (12); the three-axis lattice measurement platform (7) is a displacement platform with lattice measurement scales placed along the X, Y, and Z axes, the probe scanning module (8) holds a scanning probe, the sample stage (9) is a three-axis micron-level displacement sample stage, the laser module (10) emits laser light onto the cantilever of the scanning probe and the reflected light is processed by the optoelectronic signal processing module (11), the vibration isolation platform (12) prevents the platform from vibrating to ensure measurement accuracy, the main control computer controls the three-axis lattice measurement platform (7) to position and scan the scanning probe of the probe scanning module, and at the same time records the data of the optoelectronic signal processing module (11), and images are formed using the data of the morphology coordinate values of the sample to be measured marked in a three-dimensional coordinate system, where the lattice materials of the lattice measurement scales are the same, or two or three different ones.

Images