Research On The Fabrication Of Grating Micro-nano Structure Surface By Vibration-assisted Nanoimprint Lithography And Properties

Among many methods to improve the efficiency of light energy utilization,the preparation of micro-nano structure antireflection films can effectively reduce light reflectivity and improve transmission.As one of the micro and nano structures,grating structure has special surface properties,and are therefore widely used in various fields.Nano-imprint lithography technology stands out among other preparation techniques due to its low manufacturing cost,high efficiency and the ability to produce high-resolution grating structures over a large area.However,there are some problems in the process of nano-imprint lithography,such as the low filling rate of nano-imprint photoresist resulting in poor pattern transfer quality,excessive imprint force and damage to templates.In order to solve these problems,a non-resonant vibration-assisted nano-imprint lithography method is proposed.By applying low frequency and low amplitude one-dimensional vibration beneath the nano-imprint photoresist,the required imprint force in the imprint process can be reduced,and the filling rate of the nano-imprint photoresist to the template cavity can be increased,and the quality of the grating structure can be improved.The main research contents include:(1)The principle of sub-wavelength structure is studied,the double-sided gratings are simulated by FDTD optical analysis software,and the influence of the period parameters of the upper and lower surface gratings on the light transmittance is discussed,so as to design and optimise the double-sided grating structure with the best transmission performance.(2)The mathematical model of vibration-assisted nano-imprint is established to theoretically verify the feasibility that vibration can improve the filling effect of nanoimprint photoresist on the template cavity.By using the finite element analysis software,the vibration-assisted nano-imprint process of the upper and lower surface grating structures is simulated,the influence of the vibration parameters on the filling effect and filling stress is discussed,and the range of preferred vibration frequency and amplitude is defined.(3)According to the vibration requirement of the vibration-assisted nano-imprint,a non-resonant vibration-assisted nano-imprint device is designed.In the design of the device,the stiffness,natural frequency,and amplification ratio of the device are calculated,and the finite element analysis software is used to analyze the stiffness,modal and stress of the device.The device is then subjected to practical processing and performance tests to check whether the device could meet the requirements.(4)The vibration-assisted nano-imprint system is built to carry out the study of vibration-assisted nano-imprint experiment.The influence of the vibration parameters on the quality of the double-sided grating structure was discussed by applying different vibration parameters to the double-sided grating structure and comparing the surface profile of the experimental results.The geometric dimensions of the double-sided gratings fabricated by vibration-assisted and non-vibration nano-imprinting are measured under the same imprinting force to verify the effectiveness of the applied vibration.The surface properties of the double-sided grating structures are investigated by conducting transmittance and wettability tests.