| The principles, fabrication methods and problems of micro-electromechanical system (MEMS) are studied in this paper, with emphasis on the nano-contact that affects the MEMS performance and prevents the MEMS from going into market. Firstly, according to the physical mechanics principle, on the basis of the principle of substance structure and solid physics, the nano-contact is analyzed carefully. Secondly, an engineering practical calculation way of the nano-contact is put forwarded. Finally, the adhesion between the tip and the sample of the atomic force microscopy (AFM) is discussed. The main works and conclusions include:1) The analysis of the "stick" phenomenon. The conclusion, which "stick" problem belongs to the nano-contact problems, is drawn. The research ways of the nano-contact problem are introduced, and emphasized on the molecule dynamic and continuum medium mechanics.2) The introduction of the principles of capacitive principle, piezoresistive principle, electrostatics principle, piezoelectric principle, stunning principle and shape memory alloy principle. The fabrication processes of the MEMS are discussed, and emphasized on the silicon surface sacrificial, bulk silicon fabrication, LIGA technology and molecule manipulating technology. The fields of the MEMS, which demand further study, are put forwarded.3) The introduction of the double electron potential, with emphasis on the classical Lennard-Jones potential. The A and B constants of the Lennard-Jones potential are obtained, and followed by the key positions of the balance spot and the attract force biggest spot. The Hamaker hypothesis is discussed.4) The discover of the atomic attract force, which is got on the continuance medium method of the Hamaker theory, is not in agreement with the classical Lennard-Jones potential. The conclusions, which the Hamaker homogeneous hypothesis only holds true for the long distance between the two micro-substances, is obtained. The attract force domain of definition of the Hamaker theory: h∈(7r,∞) is obtained. The same phenomenon in the repulsive force is found by the same method. Synthesizing the attraction and repulsive force, The domain of definition of the Hamaker theory: h∈(10r,∞), which includes the repulsive force, is put forward after analyzing the rule of relative error. In addition, the Hamaker constant and digit density are analyzed. The conclusion, which the Hamaker constant and digit density are varied with the contact distance, is obtained.5) The Hamaker hypothesis distance revision theory is put forward, which is the first revision of the Harnake. hypothesis. The distance revision factors, k1 and k2, are obtained. Both of their relative errors and absolute errors are discussed. The micro continuum medium contact force equation is gotten.6) The crystal structure and space point lattice are discussed. The atom gap, which exits in the Hamaker model, Is discovered. The contradiction between the Hamaker 1and the Hamaker 2 is obtained. So the Wigner-Seitz model is put forward.7) By analyzing the double electron model, the gap revision factors of attract force and repulsive force with body center cube and face center cube are obtained. A surprised phenomenon, the air-gap revision factors are equal to the square of Wigner-Seitz size divided by the atom size when the distance tends to infinity, is discovered, and followed by the conclusion that the Hamaker theory does not hold until the distance between the substances becomes infinite and the number density is equal to the Wigner-Seitz unit.8) The error rules of the Wigner-Seitz model continuum medium method are analyzed which vary with the distance. The principle of the Hamaker hypothesis gap revision is set up. The Hamaker hypothesis is revised secondly. The nano-contact Wigner-Seitz model calculation equation is gotten.9) The discrete model of the single atom and rigid plane with the face center cube is found. The force equation between the single atom and rigid plane is obtained on discretion way. The several simulation...
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