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Author Zhang, Y.-R.; Gao, F.; Li, X.-C.; Bogaerts, A.; Wang, Y.-N.
Title Fluid simulation of the bias effect in inductive/capacitive discharges Type A1 Journal article
Year 2015 Publication Journal of vacuum science and technology: A: vacuum surfaces and films Abbreviated Journal J Vac Sci Technol A
Volume 33 Issue 33 Pages 061303
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Computer simulations are performed for an argon inductively coupled plasma (ICP) with a capacitive radio-frequency bias power, to investigate the bias effect on the discharge mode transition and on the plasma characteristics at various ICP currents, bias voltages, and bias frequencies. When the bias frequency is fixed at 13.56 MHz and the ICP current is low, e.g., 6A, the spatiotemporal averaged plasma density increases monotonically with bias voltage, and the bias effect is already prominent at a bias voltage of 90 V. The maximum of the ionization rate moves toward the bottom electrode, which indicates clearly the discharge mode transition in inductive/capacitive discharges. At higher ICP currents, i.e., 11 and 13 A, the plasma density decreases first and then increases with bias voltage, due to the competing mechanisms between the ion acceleration power dissipation and the capacitive power deposition. At 11 A, the bias effect is still important, but it is noticeable only at higher bias voltages. At 13 A, the ionization rate is characterized by a maximum at the reactor center near the dielectric window at all selected bias voltages, which indicates that the ICP power, instead of the bias power, plays a dominant role under this condition, and no mode transition is observed. Indeed, the ratio of the bias power to the total power is lower than 0.4 over a wide range of bias voltages, i.e., 0300V. Besides the effect of ICP current, also the effect of various bias frequencies is investigated. It is found that the modulation of the bias power to the spatiotemporal distributions of the ionization rate at 2MHz is strikingly different from the behavior observed at higher bias frequencies. Furthermore, the minimum of the plasma density appears at different bias voltages, i.e., 120V at 2MHz and 90V at 27.12 MHz.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000365503800020 Publication Date 2015-08-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0734-2101;1520-8559; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.374 Times cited 9 Open Access
Notes Approved (down) Most recent IF: 1.374; 2015 IF: 2.322
Call Number c:irua:126824 Serial 1229
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Author Zhang, Y.-R.; Tinck, S.; De Schepper, P.; Wang, Y.-N.; Bogaerts, A.
Title Modeling and experimental investigation of the plasma uniformity in CF4/O2 capacitively coupled plasmas, operating in single frequency and dual frequency regime Type A1 Journal article
Year 2015 Publication Journal of vacuum science and technology: A: vacuum surfaces and films Abbreviated Journal J Vac Sci Technol A
Volume 33 Issue 33 Pages 021310
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract A two-dimensional hybrid Monte Carlofluid model, incorporating a full-wave solution of Maxwell's equations, is employed to describe the behavior of high frequency (HF) and very high frequency capacitively coupled plasmas (CCPs), operating both at single frequency (SF) and dual frequency (DF) in a CF4/O2 gas mixture. First, the authors investigate the plasma composition, and the simulations reveal that besides CF4 and O2, also COF2, CF3, and CO2 are important neutral species, and CF+3 and F− are the most important positive and negative ions. Second, by comparing the results of the model with and without taking into account the electromagnetic effects for a SF CCP, it is clear that the electromagnetic effects are important, both at 27 and 60 MHz, because they affect the absolute values of the calculation results and also (to some extent) the spatial profiles, which accordingly affects the uniformity in plasma processing. In order to improve the plasma radial uniformity, which is important for the etch process, a low frequency (LF) source is added to the discharge. Therefore, in the major part of the paper, the plasma uniformity is investigated for both SF and DF CCPs, operating at a HF of 27 and 60 MHz and a LF of 2 MHz. For this purpose, the authors measure the etch rates as a function of position on the wafer in a wide range of LF powers, and the authors compare them with the calculated fluxes toward the wafer of the plasma species playing a role in the etch process, to explain the trends in the measured etch rate profiles. It is found that at a HF of 60 MHz, the uniformity of the etch rate is effectively improved by adding a LF power of 2 MHz and 300 W, while its absolute value increases by about 50%, thus a high etch rate with a uniform distribution is observed under this condition.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000355739500026 Publication Date 2015-01-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0734-2101;1520-8559; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.374 Times cited 3 Open Access
Notes Approved (down) Most recent IF: 1.374; 2015 IF: 2.322
Call Number c:irua:122650 Serial 2107
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