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

Paper PS-TuM10
Effect of an Applied-phase of Bias Pulse on a Charge Reduction on a SiO@sub 2@ Hole Exposed to Plasma Etching in a Two-frequency CCP

Tuesday, November 4, 2003, 11:20 am, Room 314

Session: Plasma Diagnostics: Processing
Presenter: T. Ohmori, Keio University, Japan
Authors: T. Ohmori, Keio University, Japan
T.K. Goto, Keio University, Japan
T. Makabe, Keio University, Japan
Correspondent: Click to Email
In a top-down nano-meter scale etching, it will be essential to develop in-situ diagnostics for plasma damage in the interface under close and complementary cooperation between optical and electric procedure. In our previous paper@footnote 1@ we have applied an emission selected computerized tomography close to the wafer exposed to plasma etching, in order to investigate the polarity and the phase of high energy charged particles incident on the wafer deeply biased by a low frequency source in RIE. A reduction in charging voltage on a contact hole bottom of SiO@sub 2@ was measured in the pulsed plasma power source in the 2f-CCP in CF@sub 4@/Ar by using a dual measurement system consisting of a temporal emission CT and a contact hole charging. In the present work, detailed correlational results of the reduction in the charging voltage are shown as a function of phase and amplitude of the single bias pulse at 500 kHz. Discussion is focused both on the injection mechanism of energetic negative charges to the wafer and on the magnitude of the negative charges. As a result, during the off-period 10 µs of VHF power source it is confirmed in the present pulsed 2f-CCP system that:(1)the magnitude of the injected negative charge increases with increasing the threshold time of the single bias pulse, and at the same time a strong reduction in the charging voltage is performed, (2)secondary a strong negative self-bias-voltage is always kept to have an efficient RIE with energetic positive ions on the wafer except for the period of the single bias pulse. @FootnoteText@ @footnote 1@T.Ohmori, T.K.Goto, T.Kitajima, and T.Makabe, Proc.of Dry Process Symposium 165(2002)Tokyo, Appl.Phys.Lett.(submitted).