TWI416110B - Horizontal atomic force microscope for horizontal and rotary scanning surface - Google Patents

Abstract

This invention is used to scan surface vertically and rotationally for the measurement of nanostructure on the surface. Which is composed of force sensing element including micro cantilever beam and probe, piezo-electrical resistance detector, aerostatic lead screws for both horizontal and feed transmission, aerostatic bearing and guide slidway, control module for compensation of surface contour, aero-bearing spindle, compensation system for thermal shift, image data acquisition and display, vibration isolator, lead screw will be used by scan and feed in large distance, piezo actuators are used in servo control for final position, rotational scan and horizontal servo control the angular position and axial position of surface scanning, respectively, feed-servo control the distance between probe and surface, the surface feature will be measured by piezo-electrical resistance detector, the position accuracies for rotational, horizontal and feed servo-control will be compensated by the thermal deformation determined by using thermal shift compensator, the relative position between probe and surface are keep on by using vibration isolator, nanostructure data of surface can finally be obtained by the determination of surface contour.

Description

Horizontal and rotating scanning surface horizontal atomic force microscope

Nano feed, aerostatic bearing spindle, aerostatic bearing, aerostatic lead screw, atomic force microscope, surface measurement

The nano surface structure made on a curved surface, a spherical surface or a circular surface is widely used in the industry, that is, the measurement and detection of the resolution of the nanometer or even the eutectic on the circular surface, the spherical surface or the curved surface. Demand; however, the resolution of the roundness meter only reaches the micro-nano or sub-nano level, so the present invention is an atomic force microscope (AFM) device for detecting the surface structure of the surface on the curved surface; at the same time, a specific probe can also be used. Needle and measurement methods, through which the physical properties and chemical properties of the surface structure of the nanometer are detected and affected by curvature or double curvature.

The idea of scanning tunneling microscopy (STM) was proposed as early as the 1950s; Benny and Rorell [1] brought the tip of the needle close to the surface of the sample to create a tunneling current. In 1979, the new microscope of STM was proposed. Patent application Please, in 1981, the first STM entity was finally produced, but the surface structure of the conductor and the semiconductor could only be observed directly. For the non-conductive material, a conductive film must be applied to the surface, so that the surface morphology and surface electronic properties can only be measured. The combined results; in 1986, Dr. Benny and Professor Quart [2] used STM to detect the change of tunnel current, so that a very sensitive microcantilever measured the change of the force between atoms, thus inventing the atomic force microscope (AFM). ), AFM, like STM, can work in different environments, measure the repulsive force between the tip and the surface atoms, and even reach the atomic resolution. It can study the force-related friction, magnetic force and electrostatic force with extremely high resolution. Multi-gravity phenomenon of interaction.

The working principle of AFM is to use a tip of the cantilever beam that is extremely sensitive to force to detect the atomic interaction between the tip and the sample, and realize the working principle of surface imaging, as shown in Figure 1. The weakly sensitive elastic microcantilever is fixed at one end, and the tip of the other end is in light contact with the surface of the sample. Although there is a very weak force (10 ^-8 ~10 ^-6 N) at the tip end of the tip and the sample surface, the micro cantilever still A slight elastic deformation occurs; the relationship between the interaction force F and the displacement of the microcantilever according to Hooke's law, the displacement can be measured to obtain the force between the tip and the sample; during the probe scanning process, The feedback circuit keeps the force between the needle tip and the sample fixed, that is, the deformation displacement of the micro cantilever is kept constant in the constant force mode, the needle tip moves up and down along with the surface undulation, and the trajectory of the needle tip up and down is recorded to obtain the surface. The signal of the shape.

The AFM image can also be obtained using the Constant height mode, that is, during the scanning process, the positioning servo return loop is used to keep the distance between the tip and the sample fixed, and the detector measures the deformation displacement of the microcantilever. The amount is used for imaging. This method can have a higher scanning speed because it does not use a force feedback loop. It is usually used when observing atomic and molecular images, but it is not suitable for samples with large surface fluctuations. Should use The mode of scanning the force mode.

The traditional detection method of AFM microcantilever deformation displacement includes tunneling current method, capacitance method and optical method, but the detection system and the micro cantilever must be aligned to detect the fixed sensor of the system, and the measurement reference point is fixed. The micro cantilever moves the test piece to scan the test piece with the micro-cantilever tip, so the traditional AFM detection method limits the scanning range and scanning speed.

[1] Binnig, G., et al., Appl. Phys. Lett., 1982, 40(2): 178.

[2] Binnig, G., Quate, C.F., Gerber, C. Phys Rev. Lett., 1986, 56: 930.

The structure of the surface scanning horizontal atomic force microscope of the present invention is shown in FIG. 2, and the components thereof are: (1) AFM body structure, (2) piezoelectric resistance detecting device for motion-sensitive component movement, and (3) scanning servo force Control or equidistance control system, (4) Piezo Actuation Module, (5) Aerostatic Bearing (C-Axis) and Aerostatic Guide (Z-Axis), (6) Thermal Drift Compensation System, (7) Image collection display and processing systems, (8) curved contour compensation control calculation module, (9) vibration isolation system, (10) probe and force sensitive components.

The invention is used for horizontally and rotating scanning curved surfaces to measure the nanostructure on the surface of the curved surface. The composition of the invention comprises a force sensitive component of a micro cantilever and a probe, a piezoelectric resistance detecting device for measuring, and an air for horizontal scanning. Static pressure lead screw drive, air static pressure lead screw drive for vertical feed, curved contour compensation control calculation module, aerostatic bearing and guide rail, aerostatic rotary scanning spindle, thermal drift compensation system, diagram Image collection display processing system and vibration isolation device, horizontal scanning and vertical feed servo piezoelectric actuator module, when using a lead screw drive when scanning or feeding a large distance, and finally using a piezoelectric actuator when accurately positioning The servo control rotates the spindle to measure the circumferential angular position of the curved surface, and the horizontal scanning servo controls the axial position of the positioning curved surface. The feed servo controls the correct distance between the positioning curved surface and the probe, and the surface feature obtained by the scanning is detected by the piezoelectric resistance. Thermal drift compensation system calculates ambient temperature change The amount of thermal deformation is compensated for the servo control positioning amount to control the rotation and horizontal scanning accuracy and feed accuracy. The vibration isolation system prevents the measurement error caused by the relative displacement of the measurement area, and the surface contour compensation calculates the nanostructure characteristics of the curved surface. News.

The curved surface workpiece made of nano structure is mounted on the rotating shaft. Both ends are supported by aerostatic two-way bearing and neck bearing. The servo motor is driven. When the servo motor rotates, the curved workpiece is rotated one turn or rotated by a limited angle. The needle is scanned, and the surface structure of the curved surface is read by the probe of the microcantilever. The surface features of the curved workpiece are transmitted through the probe, causing deformation of the microcantilever, and the deformation of the microcantilever is measured by the Wheatstone bridge. After conversion and image analysis , to get the information of the surface nanostructure features of the surface.

One end of the micro-cantilever is fixed to the micro-feeding seat, and the micro-feeding is performed by the piezoelectric actuator. The precise positioning of the probe is close to the curved surface of the workpiece, and the micro-feeding seat is mounted on the lead screw moving seat and the supporting feeding thereof. Block.

The feed assembly includes a lead screw moving seat and a feed support. The large feed of the assembly is driven by a servo motor, driven by an air static pressure lead screw, and the lead screw is supported by an air static pressure two-way bearing and an air static pressure neck bearing. The micro cantilever is given a large feed and a precise micro feed with the feed lead screw and the feed piezoelectric actuator according to the shape of the scan surface. When the feed of the assembly is moved up and down in the vertical direction, The air static pressure feed support of the assembly is guided by the feeding guide rail in the lateral direction, and the assembly seat and the feed guide rail are respectively supported and supported by the air static pressure translation, and the horizontal guide rails and the lateral horizontal and horizontal translation movements are transmitted. The micro-feed is servo-positioned by the translating piezoelectric actuator, and the piezoelectric actuator is mounted on the actuating seat. The large translational actuation of the actuating seat is driven by the horizontal servo motor to pressurize the lead screw, so that the lead screw moves the seat. In the assembly seat, the lead screw is supported by an air static pressure neck bearing and a two-way bearing.

The translation assembly seat is composed of a feed guide rail, an air static pressure translation support, a translational piezoelectric actuator seat, and a feed guide guide is introduced to the vertical assembly of the assembly seat. The movable, translational support is used to support the probe microcantilever and the sensor assembly of the Wheatstone bridge, the feed actuator assembly, and the translational scan actuator assembly.

Translational translation of the sensor Short-range precise servo positioning is driven by a translating piezoelectric actuator, the piezoelectric actuator is placed in the actuator base, mounted on the air static pressure lead screw moving seat, and the lead screw moving seat is used for horizontal scanning. The servo motor is driven by an air static pressure lead screw, which is supported by an aerostatic two-way bearing and a radial bearing.

The semiconductor film is deposited on the micro cantilever, and the semiconductor is used as a piezoelectric resistance deflection sensor. The potential difference is detected by the Wheatstone bridge, and the resistance change is calculated to reflect the strain generated by the semiconductor film, corresponding to the deformation displacement of the micro cantilever, and the pressure is utilized. The method of electrical resistance detection, the micro-cantilever can no longer be required to be fixed, thus breaking the limitation of scanning range and scanning speed.

Compared with all media of other types of bearings, the aerostatic bearing and the air static pressure guide are the only ones that can achieve a rotation accuracy of less than 10 nm and a vibration amount of less than 0.1 nm. Therefore, the present invention develops an air static pressure. The bearing is used as the bearing of the rotary platform, the air static pressure guide is used as the static pressure support of the linear feed of the worktable, the air static pressure screw is used for the long stroke feeding, the piezoelectric actuator is still used for the short stroke, and the adaptive controller is used. Long stroke positioning of the servo motor and nano precise servo positioning control of the piezoelectric actuator.

The curved surface workpiece 1 having a surface of a nanostructure is mounted on the rotating shaft 11, and both ends are supported by an aerostatic two-way bearing 311 and a neck bearing 312, and are driven by a servo motor 41. When the servo motor 41 rotates, the curved workpiece 1 is rotated one turn. Or rotating a limited angle to scan the probe, the probe 2 of the microcantilever 21 reads the surface structural features of the curved surface, and the surface features of the curved workpiece 1 are transmitted via the probe 2, causing deformation of the microcantilever 21, using Wheatstone The bridge 22 measures the deformation of the microcantilever 21, and through conversion and image analysis, obtains the information of the surface nanostructure characteristics of the curved surface.

One end of the micro-cantilever 21 is fixed to the micro-feeding seat 61, and the micro-feeding is performed by the piezoelectric actuator 51, so that the probe 2 is precisely positioned close to the workpiece curved surface 1, and the micro-feeding seat 61 is mounted on the lead screw moving seat and It supports the feed assembly 71.

The feed assembly 71 includes a lead screw moving seat 711 and a feed support 712. The large feed of the assembly 71 is driven by the servo motor 42 and is driven by the air static pressure lead screw 81. The lead screw 81 is an aerostatic two-way bearing. 312 and the air static pressure neck bearing 322 support, the micro cantilever 21 gives a large feed and precise micro feed, respectively, with the feed lead screw 81 and the feed piezoelectric actuator 51 along with the shape of the scan curved surface, the assembly When the feed of the seat 713 is moved up and down in the vertical direction, the air static pressure feed support of the assembly 71 is guided laterally by the feed guide 91, and the assembly seat 713 and the feed rail 91 are respectively moved by air static pressure. The supports 101 and 102 support horizontal and horizontal translational movements on the horizontal guides 92 and 93. The transmission micro-feed is servo-controlled by the translational piezoelectric actuator 52, and the piezoelectric actuator 52 is mounted on the actuation seat 62. The large translational actuation of the movable seat 62 is driven by the horizontal servo motor 43 to the aerostatic lead screw 82, which causes the lead screw moving base 72 to drive the assembly seat 713. The lead screw 82 is supported by the aerostatic neck bearing 332 and the two-way bearing 331.

The translating assembly 72 is composed of a feed guide 91, an aerostatic translation support 102 and 103, and a translating piezoelectric actuator base 62. The feed guide 91 is guided to the vertical up and down movement of the assembly 71, and the translation support 102 And 103 are used to support the probe 2 microcantilever 21 and the Wheatstone bridge 22 sensor assembly, the feed actuator assembly, and the translational scan actuator assembly.

The translational scanning short-range precise servo positioning of the sensor is driven by the translating piezoelectric actuator 52, which is placed in the actuator base 62, mounted to the aerostatic lead screw moving seat 72, and the lead screw moving seat The servo motor 43 for horizontal scanning is driven by the aerostatic lead screw 82, and the lead screw 82 is supported by the aerostatic two-way bearing 331 and the radial bearing 332.

Depositing a semiconductor film on the microcantilever 21, the semiconductor being used as a piezoresistive bias The sensor is used to detect 22 potential difference with Wheatstone bridge, calculate the resistance change, and reflect the strain generated by the semiconductor film, corresponding to the deformation displacement of the micro cantilever. With the method of piezoelectric resistance detection, the micro cantilever can no longer be Requires a fixed stay, thus breaking the limits of scanning range and scanning speed.

1‧‧‧Surface workpiece

2‧‧‧ probe

11‧‧‧ shaft

101, 102‧‧‧Vertical aerostatic translation support

103, 104‧‧‧ horizontal air static pressure translation support

181‧‧‧Laser light source

182‧‧‧ lens

183‧‧‧Mirror

184‧‧‧Detector

185‧‧‧Computer Control Software and Hardware

186‧‧‧ display

192‧‧‧ probe

193‧‧‧Test pieces

194‧‧‧ Piezoelectric Actuator

21‧‧‧Micro cantilever

22‧‧‧ Wheatstone Bridge

23‧‧‧ Piezoelectric Resistance Sensor

201, 202‧‧‧ transverse frame

311,321,331‧‧‧Aerostatic two-way bearing

312, 322, 332‧‧‧ aerostatic neck bearings

41‧‧‧Rotary Scanning Servo Motor

42‧‧‧Probe feed servo motor

43‧‧‧Horizontal scanning servo motor

51‧‧‧Vertical piezoelectric actuator

52‧‧‧Horizontal piezoelectric actuator

61‧‧‧Micro feed seat

62‧‧‧ Piezoelectric actuator

711‧‧‧Vertical feed assembly

712‧‧‧ translation seat

721‧‧‧Vertical guide screw moving seat

722‧‧‧Horizontal guide screw moving seat

81‧‧‧ Feeding lead screw

82‧‧‧ horizontal guide screw

91, 92‧‧‧ feed rails

93, 94‧‧‧ horizontal rails

Figure 1 Principle of atomic force microscopy (AFM)

Figure 2 Surface measurement of horizontal and rotational scanning of horizontal atomic force microscopy

1‧‧‧Surface workpiece

2‧‧‧ probe

11‧‧‧ shaft

101, 102‧‧‧Vertical aerostatic translation support

103, 104‧‧‧ horizontal air static pressure translation support

21‧‧‧Micro cantilever

22‧‧‧ Wheatstone Bridge

23‧‧‧ Piezoelectric Resistance Sensor

201, 202‧‧‧ transverse frame

311,321,331‧‧‧Aerostatic two-way bearing

312, 322, 332‧‧‧ aerostatic neck bearings

41‧‧‧Rotary Scanning Servo Motor

42‧‧‧Probe feed servo motor

43‧‧‧Horizontal scanning servo motor

51‧‧‧Vertical piezoelectric actuator

52‧‧‧Horizontal piezoelectric actuator

61‧‧‧Micro feed seat

62‧‧‧ Piezoelectric actuator

711‧‧‧Vertical feed assembly

712‧‧‧ translation seat

721‧‧‧Vertical guide screw moving seat

722‧‧‧Horizontal guide screw moving seat

81‧‧‧ Feeding lead screw

82‧‧‧ horizontal guide screw

91, 92‧‧‧ feed rails

93, 94‧‧‧ horizontal rails

Claims (1)

A horizontal and rotating scanning surface horizontal atomic force microscope for horizontal and rotating scanning surfaces to measure the nanostructure on the surface of the curved surface. The composition includes the body structure, force sensing components, and piezoresistors for measurement. Sensor, horizontal hydrostatic lead screw drive, aerostatic pilot screw drive for vertical feed, curved profile compensation control calculation module, aerostatic bearing and guide rail, aerostatic rotary scan Main axis, scanning servo equal force control or equidistance control system, thermal drift compensation system, image collection display and processing system, vibration isolation device, and horizontal scanning and vertical feed servo piezoelectric actuator module; force sensitive The component includes a micro cantilever and a probe, the probe is fixed on the free end of the micro cantilever, the micro cantilever is fixed on the piezoelectric actuator, and the piezoelectric actuator is fixed on the micro feed. Seat, the micro feed seat is fixed in the feed assembly seat, the feed assembly seat is fixed with the vertical guide screw moving seat, and the vertical feed guide screw moving seat is driven by the feed lead screw, and the probe feed servo The motor drive feed lead screw, the vertical guide screw move the seat drive feed assembly seat, the feed guide rail is fixed to the translation seat, the vertical air static pressure translation support is mounted on the feed assembly seat, and the air static pressure translation support floating straddle On the feed rail, the guide is introduced into the vertical displacement of the assembly seat along the feed rail, and the horizontal air static pressure translation support is mounted on the translation seat, which sits on the horizontal rail and the horizontal rail is fixed on the horizontal frame. The cross frame is fixed on the body structure, the horizontal piezoelectric actuator is mounted on the translation seat, the piezoelectric actuator is fixed with the horizontal guiding screw moving seat, and is driven by the horizontal guiding screw, and the horizontal scanning servo motor transmission horizontal guide The screw, the feed lead screw and the horizontal guide screw are supported by the air static pressure two-way bearing and the air static pressure neck bearing at both ends; the surface workpiece made of the nano structure is mounted on the rotating shaft, and the rotating Both ends are supported by aerostatic two-way bearing and neck bearing, and are driven by a rotary scanning servo motor. When the servo motor rotates, the curved workpiece is rotated one turn or rotated by a limited angle to scan the probe to read the probe of the microcantilever. Taking the surface structure features of the curved surface, the surface features of the curved workpiece are transmitted through the probe, causing deformation of the microcantilever. When scanning or feeding a large distance, the lead screw is used for transmission, and finally, when the precise positioning is performed, the piezoelectric actuator is used for servo transmission. The servo control rotates the spindle to measure the circumferential position of the curved surface, the horizontal scanning servo controls the axial position of the positioning surface, and the feed servo controls the correct distance between the positioning surface and the probe, and uses the Wheatstone bridge to measure the deformation of the microcantilever. The obtained surface features are detected by a piezoresistive sensor, and the thermal deflection amount calculated by the ambient temperature change is calculated by the thermal drift compensation system, and the servo control positioning amount is compensated to control the rotation and horizontal scanning precision and the feed precision, and vibration isolation. The system prevents the relative displacement of the isolation zone from causing measurement errors, and the surface contour compensation calculates the surface table. The nanostructure feature information.