Research On Characterization Methods Of Micro/Nano Structures And Surface Roughness

The rapid development of micro/nano technology and ultra-precision machining technology has put forward higher requirements for the micro/nano geometric measurement technology.As a kind of physical standard,the high precision and traceable measurement of micro/nano scale transfer standards guarantee the accurate quantity transfer and traceability of micro/nano scale geometric measurement,also it plays an important roles in micro/nano geometric measurement.In view of the measuring demands of micro and nanoscale structures and surface roughness in micro/nano scale measurement field,the characterization of micro/nano scale step,1D grating structure and surface roughness were researched.Specific works are summarized as follows:Firstly,the white light interference probe was designed and developed.Based on nano measuring machine,atomic force microscope and white light interference probe,the micro/nano scale coordinate measuring system was constructed.Based on further study of the related measurement principle of white light interferometry,theory deduction and experiments analysis of white light correlogram demodulation algorithms were conducted.Secondly,the evaluation method of step height was researched.For the defects of atomic force microscope in measuring large scale steps and field of view limitation of CCD camera,the unilateral fitting evaluation method of large scale steps was introduced.The conventional fixed interval scanning method has problems of low signal utilization and long measuring time,so far a variable speed scanning measurement method for large scale steps was proposed.Thirdly,the evaluation method of 1D grating was studied.The orthogonal scanning direction was obtained through multiple iterations when measuring.Because of the frequency resolution limitation of fast Fourier transform method,the frequency spectrum is local refined to get more accurate result using bisection method.The evaluation results of gravity center method are sensitive to sampling interval,particle contamination and probe shake,the interpolation of profile was conducted,wavelet denoising method and a simple phase correct low-pass filter hasbeen developed to remove data noise and waviness artefacts of profile.Finally,the evaluation method of surface roughness was researched.The fast Gaussian filter convolution algorithm of 2D and 3D surface roughness were derived,the computation time is shorten through iterations.Based on VC6.0 and Matlab mixed programming,the data processing software of surface roughness was developed.The software system can achieve profile acquisition,data leveling,2D and 3D surface roughness parameters evaluation,surface topography mapping,report generation and so on.In the end,a summary and prospects of the whole thesis are presented.