초임계 이산화탄소와 HF 수용액을 이용한 고 종횡비의 MEMS 구조물 건식 에칭 기술

Abstract

Dry etching for sacrifical oxide using supercritical carbon dioxide (scCO2) is studied. In order to over come conventional wet etching process and scCO2 dry etching process. Etching effect for P-TEOS as pressure, temperature, concentration of HF using aqueous solution of HF/water in supercritical carbon dioxide is investigated. MEMS of high aspect ratio(1:150) could be built without stiction using scCO2 dry etching through cantilever MEMS pattern wafer experiment. High etching speed(990nm/min) is obtained through concentration of HF and temperature change in the condition of maximum HF/H2O solubility in scCO2 (pressure range 70~350 bar). Moreover, there are some defect of remaining SiF4∙2(CH2)5NH after etching as byproduct in the previous experiment using HF/Pyridine scCO2. But in case of using HF/H2O scCO2, there was no byproduct. Hence, If we adjusted this scCO2 dry etching to semiconductor process, the effect which reducing the toxicity waste water and building nano-sized pattern of high aspect ratio.