Key Techniques on Preparing High Aspect Ratio Micro and Nano Structures

The HSQ has the advantages of high resolution, high contrast and low edge roughness. Through a lot of process experiments, the optimization conditions of the electron beam exposure dose, the proportion of the developer, the developing time and the developing temperature were explored. The relationship between electron beam exposure dose and line width was explored. The electron beam proximity effect in exposure generated by scattered electrons and backscattered electrons was effectively eliminated. Through adding appropriate NaCl in the conventional developer, the graphic contrast was improved effectively. The mechanism of action between NaCl and HSQ was analyzed. The collapse and adhesion of resist structure due to the effect of gas-liquid interfacial capillary surface tension were suppressed by the CO2 supercritical drying method. Large-area dense nano-structures with the aspect ratio of 12:1 and good steep sidewalls were obtained.