| In recent decades,Micro-Electro-Mechanical System(MEMS)technology has developed rapidly,and MEMS based systems have been widely used in different fields,including automation,aviation,consumer electronics,national defense,industrial manufacturing,medical equipment,life sciences,and electronic communications,to name a few.However,even a simple MEMS device can have very complicated multiphysical interactions between their millimeter-/micro-components,such as optical force,magnetic force,electrostatic force and van der Waals force.Therefore,understanding the interactions between components,or more fundamentally interactions between interfaces,is crucial for the manufacture and design of MEMS devices.Recently,as the most effective tool for micro-/nano-characterization,scanning probe microscope is also widely used to measure the interactions between structural interfaces.However,due to the limited size of the cantilever,it cannot load the structure exceeding 10μm in size.Moreover,because the cantilever has a low spring constant,when the probe is close to the sample surface,the probe will occur ‘jumping to contact’phenomenon,which makes it impossible to measure the interaction between the probe and the sample.To address the above issues of the conventional cantilever probe,we propose to use a quartz-crystal sensor instead of cantilever to measure the interactions between the material interfaces.This quartz-crystal sensor can not only load millimeter-scale macrostructures,but also can reach ～1 p N level precision.In addition,the spring constant of this quartz crystal sensor is more than two orders of magnitude higher than that of the cantilever probe,which can avoid the phenomenon of ‘jumping to contact’.Due to the above advantages,this kind of quartz crystal sensor has a good application prospect in the measurement of weak force.This thesis first reviews the research background,theoretical models and measurement methods of interaction between the interfaces.Besides,this article briefly describes the drawbacks of the traditional cantilever probe.The second chapter mainly introduces a kind of quartz crystal sensor instead of cantilever,and analyzes its performance.In this paper,the same structures are attached to the two prongs of the quartz crystal to reduce the quality difference of the prongs.By the way,we can improve the quality factor of the quartz crystal.Besides,the second chapter introduces the principles of the scanning probe microscope used for measurement of the weak forces and the analysis of the sensitivity of the measurememt system.The third chapter introduces the preparation process of the quartz crystal probe in detail,and discusses the details of the weak force measurement system based on the quartz tuning fork.In addition,using the tuning fork system,we quantitatively measured the interactions between interfaces in both ambient and high vacuum environments in this thesis,and carry out the corresponding theoretical analysis of the measured results.In summary,using the tuning fork system,we quantitatively measured the interactions between a sub-millimeter sphere and a flat surface in both ambient and high vacuum environments in this thesis.The experimental results show that in the atmospheric environment,not only the van der Waals force exists between the interfaces,but it is also affected by the surrounding gases.In a vacuum environment,van der Waals forces dominate the interactions between the macroscopic interfaces. |
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