Transient behaviour of CF₄rf plasmas after step changes of power source voltage

Abstract

CF4 radio-frequency (rf) plasmas are often driven in time-modulation modes to obtain higher etching performance. For dynamic and stable control of CF4 plasmas, we investigated the transient behaviour of the plasmas after step up or down of the amplitude of the power source voltage Vs(t). Using a one-dimensional fluid model, we simulated a CF4 capacitively coupled plasma that transfers from a periodic steady state to another at 0.2 Torr in a 20 mm parallel-plate gap. In addition, we compared such plasma responses to the step down to 0 V at the phases at which Vs(t) takes zero and peak values. Fundamental properties of transient CF4 plasmas were discussed.

Model and probe measurements of inductively coupled CF4 discharges

“…4,5 On the other hand, modeling of the capacitively coupled rf CF 4 discharge 1,2,6,7 has concentrated on chemical kinetics and surface reactions rather than discharge physics. However, modeling of discharge physics [8][9][10][11][12] has progressed, and important physical and chemical processes in plasma have been understood.…”

Modeling and experimental investigation of the plasma uniformity in CF4/O2 capacitively coupled plasmas, operating in single frequency and dual frequency regime

“…Carbon tetrafluoride (CF 4 ) is an industrially important gas, which is used in the selective and anisotropic removal of patterned silicon. 1 For this purpose, the physical and chemical processes in CF 4 plasmas need to be well understood to improve the plasma performance, and they have been widely investigated both experimentally [2][3][4][5][6] and theoretically [7][8][9][10][11][12][13] in capacitively coupled plasmas (CCPs). Besides measurements of the densities of negative ions 2 and high mass species, 3 special attention has been paid to the production and loss mechanisms of CF x radicals by means of laser induced fluorescence 4 and infrared absorption spectroscopy 5,6 under various conditions, since these radials play an important role in etch and polymerization processes.…”

“…Moreover, considerable effort has also been made to study the important plasma physics and chemistry in CF 4 discharges (i.e., the role of negative ion attachment, the discharge mode transition, etc.) by fluid simulations [7][8][9][10] and particle-in-cell/Monte Carlo modeling. [11][12][13] In order to control the production of radicals and improve the selectivity in etching, O 2 or other dilution gases are usually added to CF 4 discharges for practical material a) Electronic mail: yrzhang@dlut.edu.cn processing.…”

A novel merged beams apparatus to study anion-neutral reactions

“…[9][10][11] Accurate negative ion chemistry networks are important for understanding the properties of these plasmas. [12][13][14] H − chemistry in the early universe plays an important role in the collapse of primordial gas clouds and the formation of first stars and protogalaxies. [15][16][17] Uncertainties in this primordial chemistry limit our ability to model reliably this epoch of the universe.…”