Research And Application Of Electrostatic Field Assisted Imprint Lithography Technology

In this article, a novel microfabrication method, i.e. electrostatic field assisted imprint lithography is studied. Compared with the traditional imprint method, electrostatic field assisted imprint is a single step process with a fast speed and low cost, which has huge potential applications in MEMS, sensor, microelectronic device, optical material et al. We studied the electrostatic field assisted imprint lithography technology in theory first and then carried out the experiment. The result shows that micro- nano structure can be obtained in one step and it will extend application for the imprint lithography technology.Fist, the evolution mechanism of polymer film under the influence of electrostatic field is studied in theory, which includes the stability analysis of polymer film, the dynamic ana lysis in the surface of fluid, characteristic wavelength etc. Based on a software package COMSOLT M Multiphysics, the transient analysis model of multiple physical fields is develo ped to study the electrostatic- induced process and the imprint process of the microstructures and the mechanism was analyzed in detail. The influence of experimental parameters for the fabrication results has been studied in detail. The simulation results show that smaller electrode spacing and smaller period are helpful to the formation of the multilevel structures. Furthermore, lager height of the electrode protrusion, smaller initial film thickness and higher voltage will help to ac hieve the multilevel structures. In addition, we put forward a novel copy template and have studied the influence on the replication of microstructures compared to the ful y conductive type.Second, the influence of environment parameters is studied, which contains electrode spacing, initial film thickness, voltage, temperate, experimental time and template separation etc. The preparation process of the pattern template, including substrate pretreatment, lithography and electroplating, has been researched. Besides, the technical difficulties and appropriate experimental parameters was indicated. Then we produced different conductive template of grating templates and micro lens array templates.Moreover, the design parameters was put forward from the aspect o f amplitude photon sieve and the mechanical structure is fabricated. By the three steps of coating, lithography, and etching, PI film photon sieve was fabricated and the diffraction efficiency of photon sieve was measured, furthermore, the imaging performance was tested. The experimental results show that the diffraction efficiency of photon sieve is 4.916% at the wavelength of 632.8 nm, which is accounting for 73.9% of the theoretical value. For the star testing, the ideal Airy Spot with aperture of 176.70 ?m was obtained, which is very close to the value of the theoretical limit, and the error is only 4.04%. For the imaging experiments by building the resolution panel, the maximum resolution frequency of 12.2 lp/mm of photon sieve was obtained, which is approach to the spatial frequency limit of 14.4 lp/mm. It shows that the experimental results are basically in agreement with the theoretical analysis. Comparing with other diffractive elements, PI photon sieve can satisfy the application requirement of the primary mirror applied on a space telescope for its lighter weight and better performance of imaging.Finally, we conducted the pattern replication experiments. The preparation of grating microstructure based on the electrostatic field assisted imprint lithography technology is analyzed in theory and a two-dimensional transient simulation model is built to study the evolution process of grating microstructure. The grating structures are fabricated in proper environment parameters. Moreover, the pattern replication experiments of grating templates and microchannel structure templates are carried out. The experimental results show that micro structures can be obtained by one step based on the electrostatic field assisted imprint lithography technology. Therefore, the novel technology is effective and practical, which extends the application of imprint lithography technology.