원주형 DRAM 캐패시터 제작을 위한 초임계 이산화탄소 HF/H2O 건식 식각

Abstract

Method of the HF dry etching for sacrificial SiO2 layer using scCO2 is studied in order to overcome the limits of recent wet etching process related to future semiconductor industry. In this study, etching effect for SiO2 sacrificial layer by using supercritical carbon dioxide(scCO2) and HF/H2O homogeneous solution is improved and etching rate as the pressure, temperature, time change and HF concentration is studied. After etching reaction, etchant on the wafer was removed by injecting helium. Etching time is precisely controlled. Activation energy of TEOS, BPSG is calculated. Thickness of SiN on the etch selectivity of BPSG and TEOS at 40℃ is calculated to be 91 and 982 respectively. Moreover, cylinder-type semiconductor is successfully achieved without stiction using scCO2 dry etching.