title: Effect of the chamber wall on fluorocarbon-assisted atomic layer etching of SiO2using cyclic Ar/C4F8plasma.
abstract: The authors studied the effect of the temperature and chemical state of the chamber wall on process performance for atomic layer etching of SiO2using a steady-state Ar plasma, periodic injection of a defined number of C4F8molecules, and synchronized plasma-based Ar+ion bombardment. To evaluate these effects, the authors measured the quartz coupling window temperature. The plasma gas phase chemistry was characterized using optical emission spectroscopy. It was found that although the thickness of the polymer film deposited in each cycle is constant, the etching behavior changed, which is likely related to a change in the plasma gas phase chemistry. The authors found that the main gas phase changes occur after C4F8injection. The C4F8and the quartz window react and generate SiF and CO. The emission intensity changes with wall surface state and temperature. Therefore, changes in the plasma gas species generation can lead to a shift in etching performance during processing. During initial cycles, minimal etching is observed, while etching gradually increases with cycle number.
authors.affiliation: Electronic Device Systems Business Group, Hitachi High-Technologies Corporation , 794 Higashitoyoi, Kudamatsu, Yamaguchi 744-0002, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Kawakami
authors.affiliation: Department of Material Science and Engineering, Institute for Research in Electronics and Applied Physics, University of Maryland , College Park, Maryland 20742.
authors.forename: Dominik
authors.initials: D
authors.lastname: Metzler
authors.affiliation: Department of Physics, Institute for Research in Electronics and Applied Physics, University of Maryland , College Park, Maryland 20742.
authors.forename: Chen
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Material Science and Engineering, Institute for Research in Electronics and Applied Physics, University of Maryland , College Park, Maryland 20742.
authors.forename: Gottlieb S
authors.initials: GS
authors.lastname: Oehrlein