Research On Technologies Of Curved Micro Optical Structures Fabrication By Nanoimprint Lithography

Curved grating has the functions of integration of a plane grating and a lens.Curved grating instead of a plane grating and a lens, can greatly reduce the numberof the lens, so as to simplify the optical path, strengthen the integration of opticaldevices, improve the payload, and further reduce the cost, improve the stability ofthe system.Curved grating has become a major research direction of the gratingpreparation research field, its application field is constantly expanding, especially inthe ultraviolet spectrometer, surface profiler, non-contact measurement equipments.This subject mainly aims at the preparation of curved micro optical structuresby using of in-depth analysis of wet anisotropic etching mechanism of silicon,lithography, nano-imprint processes, put forward a kind of high accuracy, low cost,high yield, large size, microstructure fabrication surface diffraction grating method.The main research work is as follows:First of all, based on the mechanism of anisotropic wet etching of silicon,choice of mask, thickness of mask layer, corrosion fluid and experimental conditionson the influence of the preparation of silicon gratings, the optimal experimentscheme has been put forward, providing a theoretical basis for the preparation ofsilicon gratings.Secondly, the optimization system is designed and completed a line width of6μm periodic of isosceles blazed grating and a line width of8μm periodic of invertedpyramid diffraction grating. In {100} type silicon base surface to achieve1D/2Ddiffraction grating impression, and the effective area of grating is large(15mm×15mm), the surface roughness is low(＜30nm) and the effective coverage rate ishigh.Finally, through uv curing nano-imprinting technologies, the grating structurefrom the silicon substrate to the PDMS soft embossed impression, to the surface ofnano press printing. Test results showed that the period of the grating spacing isaccurate, the stripe is clear, the effective area ratio is high, realize the curved surfacediffraction grating of large area, high yield, high precision be micro-nanopreparation.