AVS 49th International Symposium
    Plasma Science Tuesday Sessions
       Session PS2-TuA

Paper PS2-TuA7
Film Formation, CF@sub 2@ Reactivity and Ion Effects in Fluorocarbon Plasma Systems

Tuesday, November 5, 2002, 4:00 pm, Room C-105

Session: Plasma Surface Interactions I
Presenter: I.T. Martin, Colorado State University
Authors: I.T. Martin, Colorado State University
E.R. Fisher, Colorado State University
Correspondent: Click to Email
Fluorocarbon plasmas are widely used for the deposition of fluoropolymer films possessing a variety of useful properties, such as hydrophobicity, chemical inertness, and low surface energies. Ions play an important role in plasma film deposition, either as precursors to film deposition or as bombarding species that sputter or cross-link the depositing film. In order to better understand the mechanisms of film formation, gas phase and gas-surface interaction studies are combined with the results of the characterization of films deposited from C@sub 3@F@sub 8@ and C@sub 4@F@sub 8@ plasmas. Plasma Ion-Mass Spectrometry (PI-MS) is used to identify nascent ions in the plasma systems at different RF powers, which can then be linked to film structures and reactivity measurements. Plasma conditions that minimize the formation of ions lead to the deposition of less cross-linked fluorocarbon films; conditions that enhance fragmentation of the parent gas lead to higher deposition rates within the plasmas. In addition to film characterization, we have used our Laser Induced Fluorescence (LIF) based imaging of radicals interacting with surfaces (IRIS) method to measure the surface interactions of CF@sub 2@ molecules with Si substrates during plasma processing. CF@sub 2@ surface loss coefficients determined for 25-100 W C@sub 3@F@sub 8@ and C@sub 4@F@sub 8@ plasmas show relatively high levels of scattering, which indicates that CF@sub 2@ molecules are produced at the surface in these systems. Overall, scatter coefficients measured in the C@sub 4@F@sub 8@ system are higher than those measured in the C@sub 3@F@sub 8@ system. These data are correlated with the identity of the nascent ions in the plasma systems. Results for ion free conditions are also discussed. Collectively, the data presented provide a fairly comprehensive picture of these fluorocarbon systems, from the gas-phase to the material to the plasma-surface interface.