Study Of Hybrid Measuring System And Method For Complex Surface With Micro-array Structures

As the ultra precision machining technology is developing in variety directions and evolving into a higher level,the micro/nano measuring technology is also developing constantly.According to the objects' different manufacturing processes and texture,the requirements of micro/nano measurement vary a lot.So a single kind of measuring technology is unable to meet the comprehensive requirements of the ultra-precision machining technology now,Optical Microscopy(OM),Scanning Probe Microscopy(SPM)or Scanning Electron Microscopy(SEM)is not able to meet the requirements of high efficiency,high resolution,and three dimensional morphology characteristics obtaining at the same time.A kind of hybrid measuring method which contains the vertical white light scanning interferometry and Atomic Force Microscopy(AFM)is put forward in this thesis.In order to verify that the method is feasible,a hybrid measuring system is constructed,and it is verified by measuring a micro-array structure's surface.The main work of the research includes the following aspects:The principles and features of Amplitude Modulation(AM)AFM and Frequency Modulation(FM)AFM are introduced,and the comparison and choice are made between these two operating modes.The principles of vertical white light scanning interferometry,coherent peak detection algorithm and three dimensional image mosaic method are introduced.The large-range vertical white light scanning interferometry is stated systematically.A leveling method of a class of micro-array structures' morphology characteristic is presented.A method of getting the vertex coordinates of this kind of micro-array structure's units is introduced.These two methods above are verified by simulations.The hybrid measuring system is constructed,which consist of a measuring head,a white light interferometry module,a PI feedback control module and a double feedback positioning stage.The signal processing circuit and mechanical structure are designed so that the measuring method of the hybrid measuring system can be changed freely between AFM and vertical white light scanning interferometry.A double feedback positioning stage is constructed with a nano-measuring machine(NMM)positioning stage and a piezoelectric transducer positioning stage.The white light interferometry module is set up over the measuring head.With the NMM positioning stage,the module can realize the vertical white light scanning interferometry.The measuring function of the hybrid measuring system is verified through an AFM experiment and a vertical white light scanning interferometry experiment.The measuring method of hybrid measuring system is introduced,and the unification of the coordinates of different measuring modes is put forward as well.During the hybrid measuring experiment,the low resolution morphology characteristics should be got through a vertical white light scanning interferometry experiment first.Then,level the surface's morphology characteristic and get the coordinate of the vertex of a structural unit.The coordinates of the NMM while measuring the sample in the AFM method can be calculated through the coordinate systems unification method of the hybrid measuring system.After setting the scanning parameter,an AFM measurement of the contour line through the vertex can be realized.