Research Of Lithography And Surface Topography Measurement Techniques For Three Dimensional Micro/nano Structures

Micro-nanostructures which have the merit of small volume,light weight and high integration,play an important role in the development of modern science and technology.For example,micro-nanostructures can be applied for system miniaturization,energy saving and improvement of stability,especially for 3D micronanostructures,which have arouse wide attention in research due to their complex surface profiles and special functions.However,the fabrication of 3D micronanostructures are faced with many problems due to their small size and complicated surfaces.To overcome these problems,some researches which are about the fabricatio n and detection with high efficiency and high precision for 3D micro-nanostructures are briefly introduced as following:In the fabrication of 3D micro-nanostructures,we propose the one-pixel grayscale control method based on DMD maskless lithography for 3D fabrication.As compared to traditional sterolithography,this method omits the slicing procedure for 3D model and just needs a single exposure,both of which improve the fabrication efficiency.On the other hand,the enough pixels also ensure the control precision.In addition,we also propose the nonlinear compensation method based on grayscale calibration to realize a precise control for surface profile.In this method,a calibrated curve between exposure depth and grayscale value is carried out to generate the accurate grayscale map and avoid the possible nonlinear errors introduced by calculation.Another problem in the fabrication procedure is that the rough surface characteristics may be resulted by the heterogeneous development processing.To solve this problem,we intend to optimize the surface profile through a suitable hot melting treatment.According to the changes of photoresist pattern under different melting temperatures and time,we find the best hot melt optimizaiton solution,which can improve the roughness of photoresist pattern as much as possible while ensure the little change of surface topography.The experiment results indicate that this one-single DMD maskless grayscale lithograp hy and surface optimization method based on hot melting treatment own important application in the high precision fabrication of 3D micro-nanostructures.In the surface topography measurement of 3D micro-nanostructures,two points mainly about the measurement precision and stability are studied on the base of spatial frequency domain algorithms of scanning white light interferometry(SWLI).In the frequency-domain analysis(FDA),we obtain the coherence profile and phase profile from the interference signal at the same time.The coherence profile is free of 2? ambiguity problem but is low precision,and the phase profile is just on the contrary.A combination analysis is applied to these two kind of profiles to remove the 2? ambiguity contained in phase profile.In the measureme nt processing,we also propose the difference analysis of adjacent pixels to deal with the local phase jump problems,which may be caused by the background noised and complex surface characteristics.In addition,to remove the negative influence caused by big background noises and light source fluctuations,which may lead to the bad interference signals and unstable measurement results,we propose the spatial modulation assisted SWLI.By introduc ing the spatial modulation frequency,we successfully separate the interference signals and background noises in the frequency domain.This method can effectively restrict the noises signals,improve the signal-to-noise-ratio(SNR),and ensure the final measurement precision and stability.The research about fabrication and surface topography measurement of 3D micro-nanostructures reported in this paper can not only realize a high efficiency,but also ensure the high precision and high stability,all of which are advantage for the development and application of 3D micro-nanostructures.