AVS 45th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS2-MoA

Paper PS2-MoA4
Studies of Ion Bombardment in Plasma Cleaning and Etching Gases

Monday, November 2, 1998, 3:00 pm, Room 318/319/320

Session: Diagnostics I
Presenter: J.K. Olthoff, National Institute of Standards and Technology
Authors: J.K. Olthoff, National Institute of Standards and Technology
Y. Wang, National Institute of Standards and Technology
Correspondent: Click to Email
Ion-energy distributions and relative ion fluxes have been measured in a variety of plasma etching and cleaning gases, and their mixtures, at the grounded electrode of a high density inductively-coupled plasma (ICP) reactor. The gases studied include pure CF@sub 4@ and C@sub 2@F@sub 6@, along with the following mixtures: CF@sub 4@ + Ar, CF@sub 4@ + Ar + O@sub 2@, C@sub 2@F@sub 6@ + O@sub 2@, and SF@sub 6@ + Ar. All ions exhibited fairly simple ion-energy distributions that were indicative of the plasma potential. For pure CF@sub 4@, the two dominant ions observed were CF@sub 3@@super +@ and CF@super +@, but 3 other ions exhibited intensitites that were within a factor of 3 of the dominant ions. Similar behavior was observed in CF@sub 4@ + Ar mixtures with the addition of a significant flux of Ar@super +@ ions. For CF@sub 4@ + Ar + O@sub 2@ mixtures, 9 different ions exhibited fluxes whose magnitudes were within a factor of 2 of each other, thus indicating the complexity of the plasma-surface interactions in multi-component gases. In pure C@sub 2@F@sub 6@, CF@sub 3@@super +@ was the dominant ion, with only minor contributions observed from other ions. In mixtures of C@sub 2@F@sub 6@ and O@sub 2@, a host of other ions are formed, but the dominant ions are either CF@sub 3@@super +@ or O@sub 2@@super +@, depending upon the mixture. In SF@sub 6@ + Ar mixtures, all of the SF@sub x@@super +@ ions are observed, with the lower mass ions exhibiting larger intensities.