Design Of AFM Microcantilever Spring Constant Calibration System Based On Homemade Precision Balance

As an important tool for exploring the mechanical and physical properties of materials at the nanoscale,atomic force microscopy(AFM)is widely used in nanomechanics,life sciences,semiconductor manufacturing,and nanofabrication.In the AFM-based mechanical test,the AFM microcantilever plays a crucial role,so it is very urgent to carry out the AFM microcantilever spring constant calibration study.In this paper,the design and key technology research of the micro-cantilever spring constant calibration system based on flexible mechanism and micro-nano-magnitude micro-force measurement are carried out.The main research works are as follows:The principle design of the AFM micro-cantilever spring constant calibration system was completed based on the balance method,and the system structure design and simulation analysis were performed.A micro-displacement feed control is implemented using a precision stage,and the homemade precision balance is used to measure the bending force on the probe,and the spring constant of the micro-cantilever is calculated from the obtained force-displacement curve.The finite element static simulation and thermal deformation simulation verified the rationality of the system structure design.A flexible suspension mechanism with multi-stage spiral hinge was designed,and the stiffness theory modeling,simulation analysis and dynamic performance analysis were performed.Based on the theory of elastic mechanics,research on stiffness modeling of flexible suspension mechanism was carried out.The finite element simulation verified that the structure has good motion decoupling performance.The step response test results show that the dynamic performance of the structure meets the system experimental requirements.An electromagnetic force calibration system was designed based on the electromagnetic theory,and the structure design and electromagnetic force calibration experiments of the electromagnetic drive balance were carried out.Experimental research shows that the electromagnetic force calibration system can realize the synchronous and precise measurement of micro-force and micro-displacement.This system was used to calibrate the Z-direction stiffness of the flexible suspension mechanism.The experimental research of the AFM micro-cantilever spring constant calibration system was completed.A homemade precision balance system was built based on the flexible suspension mechanism.Weighing experimental studies showed the precision of homemade precision balance system is 0.105 μN.An AFM microcantilever spring constant calibration system was built based on the precision balance system.The experimental study of the spring constants calibration shows that the system has high measurement accuracy.The above research enriches the study on the calibration method and system of AFM micro-cantilever spring constant,and provides important guarantee and reference for the further application of AFM.