Study Of Superlens Lithography

Due to the diffraction limit, traditional optical lithography is hard to meet the increasing microfabrication requirements of advanced optoelectronics. It’s necessary to develop new nanoscale lithography techniques. As a novel high-resolution imaging technique, superlens lithography has attracted widespread attention because of its low cost and the ability to achieve the so-called "perfect imaging". In this thesis, the technique was investigated as follows:According to perfect imaging principle based on the characteristics for the left-handed materials, we compared the differences between perfect lens and superlens structure with respect to the coupling mechanism of surface plasmons. A superlens structure toward experiment goal was designed, and its near-field optical transfer function was established to explore the parameter space of each layer. Superlens lithography was simulated using the FDTD method, which demonstrates the feasibility of the designate structure.In order to obtain nanoscale mask, colloidal microspheres self-assembly technique was studied, which enables low cost. Polystyrene(PS) microspheres were synthesized by using emulsifier-free emulsion polymerization method with the monodisperse rate less than15%. The factors affecting self-assembly were explored. A novel self-assembly method was proposed to simply and efficiently obtain a large area of the closely packed PS spheres monolayer film, with the defect-free area over100μm2.The experimental superlens structure was built up. The considerations of design were also discussed. The procedure of superlens imaging experiment was detailed and the imaging results were characterized using related instruments, e.g. scan electronic micrpscope., Firstly, the nanosclae triangle mask array was fabricated by combination of self assembly and deposition coating. Then the PMMA layers were spin-coated on the mask sandwiched by the process of silver coating, where the process factors were optimized. Finally, microsclae and nanoscle superlens lithography were achieved.4micro lines were patterned with high fidelity, which demonstrates superlens lithography is superior to traditional contact lithography. Nansocale triangular array with side length of190nm was successfully replicated into the photoresist, indicating our superlens structure can realize the resolution limit down to1/7of the incident wavelength.