Characterization of iodoheptafluoropropane as a dielectric etchant. I. Process performance evaluation

An array of experiments was carried out using 1-iodoheptafluoropropane as a process gas in a typical dielectric etch application. An inductively coupled high density plasma tool was used for the work. Process performance was characterized using TEOS oxide etch rate, resist selectivity metrics, sidewall profile, and stop layer behavior as criteria. The impact of various process variables, including, source power, bias power, etch glass flow, additive gas (CH3F) flow, roof, wall, and chiller temperatures, and pressure was determined. Overall, the data obtained suggest that 1- and 2-iodoheptafluoropropane can be employed as etchant for dielectric etch applications.