CN109186434B - Non-contact sub-nanometer sensing method and device based on three-dimensional quantum tunneling - Google Patents

Abstract

A non-contact sub-nanometer sensing method and a device based on three-dimensional quantum tunneling belong to the precise sensing and measuring technology; aiming at a conductor measured object, the method adopts a three-dimensional quantum tunneling principle for sensing, firstly, an aiming gap between the measured object and a micrometering ball is adjusted to a tunneling working interval, then a bias electric field generating system is adopted to generate a bias voltage to be loaded between the micrometering ball and a measured object to form a bias electric field, then the aiming gap is converted into a sensing signal through the generation of the quantum tunneling effect, and then the aiming gap information is extracted through a tunneling signal detection system with sub-nanometer resolution; the invention also provides a sensing device; the invention effectively considers the characteristics of sub-nanometer resolution, three-dimensional isotropy and non-contact sensing, and can realize high resolution measurement of the micro-nano/micro structure with large depth-to-width ratio.

Description

Non-contact sub-nanometer sensing method and device based on three-dimensional quantum tunneling

technical field

The invention belongs to the technical field of precision sensing and measurement, and mainly relates to a non-contact sub-nanometer sensing method and device based on three-dimensional quantum tunneling.

Background technique

With the increasing level of precision machining and manufacturing, micro-nano/micro structures with large aspect ratio features are applied in cutting-edge technology fields, and sensing methods and sensing probes for precision measurement of such structures have become current Research hotspots. High resolution and aiming accuracy, three-dimensional isotropy and non-destructive rapid measurement capabilities are the key elements to realize high-precision measurement of large aspect ratio structures. However, it is difficult to achieve sub-nanometer high resolution, three-dimensional isotropy, large aspect ratio measurement capability and wireless Effective consideration of damage measurement characteristics and high-precision measurement.

At present, the existing precision measuring head and sensing technology solutions can be divided into three types according to the basic principles: the micro-force contact measurement solution, the scanning probe solution and the focused light probe solution. It is difficult for the micro-force contact measurement scheme to obtain the matching two-dimensional in-plane and axial sensitivity characteristics perpendicular to the measuring rod at the same time. Problems such as the attitude error of the measuring head are more prominent, and it is difficult to achieve true three-dimensional measurement. Due to its poor dynamic characteristics, it is impossible to achieve rapid measurement without damage; scanning probes and focused light probes generally only have one-dimensional sensitivity characteristics, and do not have the potential to achieve high lateral resolution. With motion scanning, they can only achieve two-and-a-half-dimensional measurement at most. Does not have true three-dimensional measurement capability. Therefore, for the measurement of large aspect ratio structures, it is urgent to propose a sensing technology solution with sub-nanometer high resolution, true three-dimensional, large aspect ratio measurement capabilities and non-contact measurement features.

In response to this problem, Harbin Institute of Technology proposed a sensing measurement method based on the principle of spherical scattering electric field (1. Ultraprecision 3D probing system based on spherical capacitive plate. Sensors and Actuators A: Physical, 2010; 2. Ultraprecision 3D probing system based on spherical capacitive plate. Precision non-contact 3D aiming and measuring sensor, Chinese patent number: ZL200910072143.2). The technical features of this sensing technology solution are: (1) For the first time, the principle of spherical scattering electric field is applied to a metal measuring ball to make it as a spherical capacitive plate to realize non-contact measurement, so that the measuring head has the ability of rapid measurement without damage ; (2) The sensing characteristics of this technical solution are closely related to the diameter of the metal measuring ball, and the sensing resolution becomes worse as the diameter of the metal measuring ball decreases; the minimum diameter of the measuring ball that has been realized in the project is 500 μm, At present, it is still impossible to measure the large aspect ratio structure of the micro-nano scale.

Chongqing University of Technology proposed a nano-displacement sensor scheme based on tunnel effect (a contact nano-displacement sensor based on tunnel effect, Chinese Patent No.: ZL201010101154.1). The technical characteristics of this scheme are: (1) This scheme is a micro-force contact measurement scheme. During the measurement process, the probe touches the object to be measured, and the vertical height change of the surface to be measured is transmitted to the probe and graphite through the guide rod. block spacing, and use the one-dimensional tunnel effect principle to sense the distance between the probe and the graphite block as a sensitive unit, which can achieve vertical nanoscale high resolution; (2) because the sensing technology scheme uses Probes only have vertical high-resolution measurement capabilities, and basically do not have horizontal measurement capabilities, that is, they only have vertical one-dimensional measurement capabilities but not three-dimensional measurement capabilities, so they cannot measure the size parameters and horizontal dimensions of small structures with large aspect ratios. (3) Since the probe and the measured object need to be in contact to cause tunneling between the probe and the graphite block, there is a risk of scratching the surface to be measured and the probe, so the dynamic characteristics of the contact sensing technology scheme Poor, it is difficult to achieve fast and non-destructive measurement; (4) Like all contact probes, the measurement force deformation will inevitably introduce errors and lead to a decrease in accuracy when the length of the measuring rod increases.

Schottky Schottky emission effect in surface topography: Method and application. International Journal of Nanomanufacturing, 2011; 2. Electrical probing for dimensional micro metrology. CIRP Journal of Manufacturing Science and Technology, 2008). The technical characteristics of the sensing technology scheme are: (1) The scheme uses the Schottky radiation effect as the sensing principle, which is a non-contact sensing principle, and can theoretically achieve rapid measurement without damage; (2) The research literature is A preliminary exploration of the principle, the probe is composed of solid metal rods and metal balls directly welded, no complete and specific technical solutions have been given for the measurement of structures with large aspect ratios, and no mechanical structure and signal transmission of the probe have been given Technical solutions such as shielding and shielding interference cannot realize the actual engineering measurement of structures with large aspect ratios.

In summary, through the innovation of sensing measurement methods and devices, a sensing technology solution that effectively takes into account the sub-nanometer resolution, three-dimensional isotropy, large aspect ratio measurement capability and non-destructive rapid measurement capability of sensing is provided. The precision measurement of micro-nano/microstructures with large aspect ratio is of great significance.

Contents of the invention

The purpose of the present invention is to provide a non-contact sub-nano sensing method and device based on three-dimensional quantum tunneling to solve the problems existing in the high-aspect-ratio micro-nano/micro-structure precision measurement in the prior art, in order to realize the sensing An effective combination of sub-nanometer resolution, three-dimensional isotropic properties, large aspect ratio and non-destructive rapid measurement capabilities.

Technical solution of the present invention is:

A non-contact sub-nanometer sensing method based on three-dimensional quantum tunneling, the sensing method comprising the following steps:

① Use the probe attitude adjustment mechanism to adjust the attitude of the tunneling probe relative to the measured piece, so that the tunneling probe enters the aiming attitude; then use the measurement drive mechanism to drive the tunneling probe or the tested piece, between the two After the relative distance enters the tunneling working area, the measuring driving mechanism stops driving;

②A bias electric field generation system is used to generate a bias voltage to form a bias electric field between the micrometer ball and the tested object, and then through the adjustment and control of the bias electric field, a three-dimensional Quantum tunneling effect, which converts the aiming gap between the micrometer ball and the tested object into a sensing signal;

③A tunneling signal detection system is used to detect and process the sensing signal in the above ②, and according to the model of the corresponding relationship between the aiming gap and the sensing signal, the aiming distance between the micrometer ball and the measured object is extracted with sub-nanometer resolution. Gap information to realize three-dimensional, sub-nanometer resolution sensing and measurement.

A non-contact sub-nanometer sensing device based on three-dimensional quantum tunneling, including a tunneling probe, a tunneling signal processing system, a probe attitude adjustment mechanism, an anti-collision safety protection mechanism, and a measurement drive mechanism. The tunneling probe It is composed of a micrometer ball, a signal transmission mechanism, a shielding mechanism, a card loading mechanism, a signal connector, an insulating part and a signal line. The micrometer ball is connected to the lower end of the signal transmission mechanism, and the upper end of the signal transmission mechanism is connected to the The signal connectors are connected, the main body of the signal transmission mechanism is located in the shielding mechanism, the shielding mechanism is assembled on the clamping mechanism, and insulating parts are assembled in the shielding mechanism, the signal connector is connected to the signal transmission cable, and the shielding mechanism, the clamping mechanism and the signal connection The shell of the device is seamlessly connected with the shielding layer of the signal transmission cable; the tunneling signal processing system is composed of a bias electric field generation system, a tunneling signal detection system, a current limiting unit, a communication cable and an instrument main control computer. The electric field generation system and the tunneling signal detection system are respectively connected to the main control computer of the instrument through communication cables; the signal connector of the tunneling probe, the current limiting unit, the tunneling signal detection system, the bias electric field generation The signal transmission cables are sequentially connected in series to form a sensor signal detection circuit; the tunneling probe is assembled on the probe attitude adjustment mechanism, the probe attitude adjustment mechanism is fixedly assembled with the anti-collision safety protection mechanism, and the measurement drive mechanism Installed on the anti-collision safety protection mechanism or the tested part.

The technological innovation of the present invention and the good technical effect that produces are in:

(1) The principle of three-dimensional quantum tunneling is used to realize precise sensing, and at the same time, it realizes sub-nanometer resolution and non-contact measurement capabilities. When the diameter of the micrometer ball is as small as 1 μm, the sensing characteristics of sub-nanometer resolution can still be kept unchanged, thus significantly The minimum measurable size is reduced; the non-contact measurement method can realize fast measurement without damage, and avoid friction, wear and damage to the test piece, and avoid the problem that the measurement force deformation restricts the measurement accuracy and the measurable depth-to-width ratio. dynamic characteristics of the head;

(2) The sensing technology solution can realize three-dimensional isotropic characteristic sensing and has three-dimensional measurement capability. It can not only measure the shape/morphological characteristics of micro/nano/small large aspect ratio structures, but also measure vertical depth, lateral The measurement of geometric parameters of size and space coordinates has the characteristics of isotropy, three-dimensional sub-nanometer resolution and precision;

(3) Due to the use of the three-dimensional quantum tunneling principle and the micrometer ball structure, this technical solution can realize three-dimensional isotropic and non-contact sensing characteristics, so it can solve the problem of measuring the large depth and width of the conductor material in the existing sensing technology solution The problem that the accuracy decreases with the increase of the aspect ratio when compared with the micro/nano/micro structure can increase the maximum measurable aspect ratio.

The invention can effectively take into account sub-nanometer resolution, three-dimensional isotropy, and large aspect ratio measurement capability, and provides an effective sensing measurement method and device for precision measurement of large aspect ratio micro/nano/micro structures.

Description of drawings

Figure 1 is a schematic structural diagram of a non-contact sub-nanometer sensing device based on three-dimensional quantum tunneling in which the measurement drive mechanism is installed on the anti-collision safety protection mechanism;

Fig. 2 is a schematic structural diagram of a non-contact sub-nano sensing device based on three-dimensional quantum tunneling in which the measurement drive mechanism is installed on the measured object;

Figure 3 is an actual measurement result of the relationship between the measured distance and the tunnel current.

Part number description in the figure: 1 Tunneling probe, 2 Tunneling signal processing system, 3 Probe attitude adjustment mechanism, 4 Anti-collision safety protection mechanism, 5 Measurement drive mechanism, 6 Micro measuring ball, 7 Signal transmission mechanism, 8 Shielding mechanism, 9 card loading mechanism, 10 signal connector, 11 signal transmission cable, 12 bias electric field generation system, 13 tunneling signal detection system, 14 current limiting unit, 15 DUT, 16 communication cable, 17 instrument main control computer , 18 insulation components, 19 signal wires.

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

A non-contact sub-nanometer sensing method based on three-dimensional quantum tunneling, the sensing method comprising the following steps:

① Use the probe attitude adjustment mechanism to adjust the attitude of the tunneling probe relative to the measured piece, so that the tunneling probe enters the aiming attitude; then use the measurement drive mechanism to drive the tunneling probe or the tested piece, between the two After the relative distance enters the tunneling working area, the measuring driving mechanism stops driving;

②A bias electric field generation system is used to generate a bias voltage to form a bias electric field between the micrometer ball and the tested object, and then through the adjustment and control of the bias electric field, a three-dimensional Quantum tunneling effect, which converts the aiming gap between the micrometer ball and the tested object into a sensing signal;

③A tunneling signal detection system is used to detect and process the sensing signal in the above ②, and according to the model of the corresponding relationship between the aiming gap and the sensing signal, the aiming distance between the micrometer ball and the measured object is extracted with sub-nanometer resolution. Gap information to realize three-dimensional, sub-nanometer resolution sensing and measurement.

A non-contact sub-nanometer sensing device based on three-dimensional quantum tunneling, including a tunneling probe 1, a tunneling signal processing system 2, a probe attitude adjustment mechanism 3, an anti-collision safety protection mechanism 4, and a measurement drive mechanism 5. The tunneling probe 1 is composed of a micrometer ball 6, a signal transmission mechanism 7, a shielding mechanism 8, a card loading mechanism 9, a signal connector 10, an insulating component 18 and a signal line 19. The micrometer ball 6 and the signal transmission mechanism The lower ends of 7 are connected, and the upper end of signal transmission mechanism 7 is connected with signal connector 10 through signal line 19. The main body of signal transmission mechanism 7 is located in shielding mechanism 8, and shielding mechanism 8 is assembled on the card-loading mechanism 9. The insulating part 18 is equipped inside, the signal connector 10 is connected to the signal transmission cable 11, and the shell of the shielding mechanism 8, the clamping mechanism 9 and the signal connector 10 is seamlessly connected with the shielding layer of the signal transmission cable 11; the tunneling signal processing The system 2 is composed of a bias electric field generation system 12, a tunneling signal detection system 13, a current limiting unit 14, a communication cable 16, and an instrument main control computer 17. The bias electric field generation system 12 and the tunneling signal detection system 13 communicate The cables 16 are respectively connected to the main control computer 17 of the instrument; the signal connector 10 of the tunneling probe 1, the current limiting unit 14, the tunneling signal detection system 13, the bias electric field generation system 12, and the DUT 15 pass through the signal transmission cable 11 connected in series to form a sensing signal detection circuit; the tunneling probe 1 is assembled on the probe attitude adjustment mechanism 3, the probe attitude adjustment mechanism 3 is fixedly assembled with the anti-collision safety protection mechanism 4, and the measurement drive The mechanism 5 is installed on the anti-collision safety protection mechanism 4 or the tested object 15 .

The micrometer ball 6 is made of stainless steel or tungsten carbide, and the surface of the ball is plated with a thin film of gold or platinum.

The diameter of the micrometer ball 6 is within the range of φ1 μm˜φ1 mm.

The probe attitude adjustment mechanism 3 is a two-dimensional flexible hinge, two-dimensional air bearing or air bearing structure.

Both the shielding mechanism 8 and the signal transmission cable 11 are of multi-coaxial structure.

An embodiment of the present invention is given below with reference to FIG. 1 and FIG. 3 . FIG. 1 is a schematic structural diagram of a non-contact sub-nanometer sensing device based on three-dimensional quantum tunneling of the present invention. In this embodiment, the measurement driving mechanism 5 drives the tunneling probe 1 . The surface to be tested of the tested piece 15 is a cylindrical surface in a small hole. The micro measuring ball 6 in the tunneling probe 1 is a stainless steel ball, and the surface is plated with a thin film of a gold material. The wall thickness of the shielding mechanism 8 is 20 μm. The signal transmission mechanism 7 is electrically connected with the micrometer ball 6 by welding. The shielding mechanism 8 and the signal transmission mechanism 7 are coaxially assembled to form a coaxial structure, and the two are insulated by an insulating component 18 made of insulating material, and the components are reliably insulated and positioned. The shielding mechanism 8 is clamped on the clamping mechanism 9, and the clamping mechanism 9 is assembled on the probe attitude adjustment mechanism 3, and the probe attitude adjustment mechanism 3 is assembled with the anti-collision safety protection mechanism 4. The probe attitude adjustment mechanism 3 is a two-dimensional flexible hinge structure. The anti-collision safety protection mechanism 4 adopts a magnetic suction type protection mechanism and is fixed on the measurement driving mechanism 5 . The measurement drive mechanism 5 has sub-nanometer displacement resolution. The bias electric field generation system 12 and the tunneling signal detection system 13 are connected to the instrument main control computer 17 through the communication cable 16, and the instrument main control computer 17 controls both.

First, adjust the relative position of the tunneling probe 1 and the measured object 15, and control the measurement driving mechanism 5 to drive the tunneling probe 1 so that the micro-probe 6 gradually approaches the surface to be measured of the measured object 15. The distance gradually decreases until it enters the tunneling working range. At this time, the bias electric field generating system 12 is adjusted so that the output set constant voltage is applied to form a bias electric field between the micrometer ball 6 and the tested object 15. The adjustment and control of the electric field causes a three-dimensional quantum tunneling effect to occur between the micrometer ball 6 and the test piece 15, and the gap information between the micrometer ball 6 and the test piece 15 is converted into a sensing signal. At the same time, the tunneling signal processing system 2 is monitored, and the sensing signal is processed by controlling the tunneling signal detection system 13 to obtain the aiming gap between the measured object 15 and the micrometer ball 6 . A measured curve of the relationship between the normalized measured distance and the normalized tunneling current is shown in Figure 3, and a measurement model can be established accordingly.

FIG. 2 shows another embodiment of the present invention, the measurement drive mechanism 5 drives the object under test 15 . Fix the test piece 15 on the measurement drive mechanism 5, and the test drive mechanism 5 drives the test piece 15 close to the micro-probe 6 of the tunneling probe 1 to complete the measurement. The tunneling probe 1 is connected and fixed with the probe attitude adjustment mechanism 3 and the anti-collision safety protection mechanism 4, and can be installed on the Z-axis motion mechanism of the coordinate machine for easy measurement.

Claims (3)

1. A method for sensing by using a non-contact sub-nanometer sensing device based on three-dimensional quantum tunneling is characterized by comprising the following steps: the non-contact sub-nanometer sensing device based on three-dimensional quantum tunneling comprises a tunneling measuring head (1), a tunneling signal processing system (2), a measuring head posture adjusting mechanism (3), an anti-collision safety protection mechanism (4) and a measurement driving mechanism (5); the tunneling measuring head (1) is composed of a micro measuring ball (6), a signal transmission mechanism (7), a shielding mechanism (8), a card installing mechanism (9), a signal connector (10), an insulating part (18) and a signal line (19), wherein the micro measuring ball (6) is connected with the lower end of the signal transmission mechanism (7), the diameter of the micro measuring ball (6) is in the range of phi 1 mu m-phi 1mm and is made of stainless steel or tungsten carbide materials, a gold or platinum material film is plated on the surface of a ball body, the upper end of the signal transmission mechanism (7) is connected with the signal connector (10) through the signal line (19), the main body of the signal transmission mechanism (7) is located in the shielding mechanism (8), the shielding mechanism (8) is assembled on the card installing mechanism (9), the insulating part (18) is assembled in the shielding mechanism (8), the signal connector (10) is connected with the signal transmission cable (11), and the shells of the shielding mechanism (8), the card installing mechanism (9) and the signal connector (10) are connected with a shielding layer of the signal transmission cable (11); the tunneling signal processing system (2) is composed of a bias electric field generating system (12), a tunneling signal detecting system (13), a current limiting unit (14), a communication cable (16) and an instrument main control computer (17), wherein the bias electric field generating system (12) and the tunneling signal detecting system (13) are respectively connected with the instrument main control computer (17) through the communication cable (16); a signal connector (10), a current limiting unit (14), a tunneling signal detection system (13), a bias electric field generation system (12) and a tested piece (15) of the tunneling probe (1) are sequentially connected in series through a signal transmission cable (11) to form a sensing signal detection loop; the tunneling measuring head (1) is assembled on the measuring head posture adjusting mechanism (3), the measuring head posture adjusting mechanism (3) is fixedly assembled with the anti-collision safety protection mechanism (4), and the measuring driving mechanism (5) is installed on the anti-collision safety protection mechanism (4) or a measured piece (15);

the sensing method comprises the following steps:

(1) adjusting the posture of the tunneling measuring head relative to the measured piece by adopting a measuring head posture adjusting mechanism to enable the tunneling measuring head to enter an aiming posture; then, the tunneling measuring head or the measured piece is driven by the measuring driving mechanism, and the measuring driving mechanism stops driving after the relative distance between the tunneling measuring head and the measured piece enters a tunneling working interval;

(2) a bias electric field generating system is adopted to generate bias voltage to be loaded between the micro measuring ball and the measured piece to form a bias electric field, then, the three-dimensional quantum tunneling effect is generated between the micro measuring ball and the measured piece through the adjustment and control of the bias electric field, and the aiming gap between the micro measuring ball and the measured piece is converted into a sensing signal;

(3) and (3) detecting and processing the sensing signals in the step (2) by adopting a tunneling signal detection system, and extracting aiming gap information between the micro-measuring ball and the measured piece by using sub-nanometer resolution according to a model of the corresponding relation between the aiming gap and the sensing signals so as to realize three-dimensional and sub-nanometer resolution sensing and measurement.

2. The method of claim 1, wherein: the measuring head posture adjusting mechanism (3) is of a two-dimensional flexible hinge, a two-dimensional air bearing or an air ball bearing structure.

3. The method of claim 1, wherein: the shielding mechanism (8) and the signal transmission cable (11) are both of a multi-coaxial structure.

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