Use of 2H-heptafluoropropane, 1-iodoheptafluoropropane, and 2-iodoheptafluoropropane for a high aspect ratio via etch in a high density plasma etch tool

Abstract

An issue currently facing the semiconductor industry is the use and emission of perfluorocompounds (PFCs), gases which are believed to contribute to global warming, in a number of plasma processes used in integrated circuit manufacture, including wafer patterning. Several approaches to reducing emissions of these compounds are being considered, namely abatement, recapture/recovery, process optimization, as well as the development of alternative chemistries as PFC substitutes. The authors present here the results of an effort to test several alternatives in a silicon dioxide etch application (high aspect ratio via etch). 2H-heptafluoropropane, 1-iodoheptafluoropropane, and 2-iodoheptafluoropropane, were tested in an Applied Materials Centura 5300 high density plasma etch tool. Fourier transform infrared spectroscopy was used to analyze the process effluent. The process performance and emissions of the alternative etchants were compared to those of a standard chemistry on the Centura 5300 etch tool.