AVS 50th International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS-TuA

Paper PS-TuA9
Kinetic Study on SiO@sub 2@ Dry Etching Process by Chemical Reaction Engineering Approach

Tuesday, November 4, 2003, 4:40 pm, Room 315

Session: Dielectric Etch
Presenter: T. Tokimitsu, University of Tokyo, Japan
Authors: T. Tokimitsu, University of Tokyo, Japan
Y. Shimogaki, University of Tokyo, Japan
Correspondent: Click to Email
Kinetic study on plasma process to etch SiO@sub 2@ films using C@sub 4@F@sub 8@ was made by chemical reaction engineering approach. In the present study, we assumed that the reactor as a CSTR (continuously stirred tank reactor) and examined the residence time dependency of gaseous species concentration. This approach is quite effective to elucidate the reaction mechanism that governs the performance of plasma reactor. Ionization voltage controlled AMS (appearance mass spectrometry) was conducted and it was found to be possible to measure the absolute concentration of each molecule. The residence time dependency of C@sub 4@F@sub 8@, C@sub 2@F@sub 4@ and C@sub 2@F@sub 6@ concentrations were measured by this technique. It was found that the main species in plasma changed from C@sub 4@F@sub 8@ to C@sub 2@F@sub 4@, and finally changed into C@sub 2@F@sub 6@ as residence time gets longer. C@sub 2@F@sub 4@, whose residence time dependency had a bowed profile, was the species to deposit a-C:F films and to prevent SiO@sub 2@ etching. O@sub 2@ addition to this plasma chemistry accelerate the decomposition of C@sub 4@F@sub 8@ and suppresses the C@sub 2@F@sub 4@ concentration. The residence time dependency of etching profiles were examined and discussed. Moreover, to investigate the surface reaction of SiO@sub 2@ etching, test structure was employed to make detail analysis through feature scale study. The gas phase analysis made by AMS method and the measurement of residence time dependency of each species concentration combined with feature scale analysis were sensitive tool to understand the major reaction path.