Study On The Capillary Force Lithography And Its Application

Traditional photolithography has been the dominant technology to manufacturethe large-scale integrated circuit in semiconductor industry. However, traditionalphotolithography requires the very expensive equipment from one hand and isgradually approaching its resolution limit from the other hand so that it is alwaysinteresting to develop new lithographic technologies to replace the traditionalphotolithography. Capillary force lithography as an alternative lithographictechnology is a novel non-traditional lithography technology and has been developedfor more than one decade. Capillary force lithography has a few advantages over thetraditional photolithography technology:1) it doesn’t need expensive equipment;2)it has a very high resolution;3) the fabrication process is simple and short;4) themold is reusable so that the fabrication cost is significantly saved;5) it can beadapted for large-scale nanofabrication in larger area. Up to now, the most reportedworks on capillary force lithography are implemented on the plane surfaces ratherthan the curved surfaces. Moreover, the most reported researches are focusing on theexperiments. There is nearly no work is reported on the rigorous numericalsimulation of the process but just some work on the rough qualitative analysis whichcan not predict the fabrication process precisely. In view of the above research situation, this thesis carries on a deep research on the micro-and nano-fabricationon the curved surfaces in large area by using the capillary force lithography. At thesame time, a rigorous finite element simulation method was employed to simulatethe dynamic physical process of capillary force lithography. The main work down inthis thesis includes:In experiment:1) Capillary force lithography on3D curved surfaces wasresearched. Micro and nanogratings with concentric circular structures on3D curvedsurfaces were successfully fabricated by employing this technology. The heights ofthe fabricated structures obtained in our experiments have reached65%and83%ofthe masters for micro and nanostructures respectively;2) Dewetting assistedcapillary force lithography was found and developed. We found that the resolution ofthe capillary force lithography can be enhanced for two folds by this technology. Inthe thesis, a period of215nm grating was obtained by using the master gratingwhose period is430nm;3) The process of fabricating sub-wavelength antireflectionstructures by capillary force lithography was developed. The sol-gel antireflectionstructures were fabricated on the surface of optical elements by soft lithography. Thefabricated antireflection structures can effectively reduce the the reflectance ofoptical elements surface by about1%in the range of visible light.In theory: A simulation model of capillary rise phenomenon in the closedcapillary tube was built by utilizing the COMSOL Multiphysics simulation software.How the contact angle, the diameter of capillary tube and the inner pressure of thetube affect the height of the gas/liquid interface was studied systematically. Incomparison with the experimental results, the model is found to be able to predictthe dynamic fabrication process precisely. This will make the study on capillaryforce lithography easier.At present, the capillary force lithography is still immature and extensive workneeds to be done to make the technology more practical for industry. The work downin this thesis can be helpful for those following researchers to catch up with this newtechnology.