Optical emission intensity overshoot and electron heating mechanisms during the re-ignition of pulsed capacitively coupled Ar plasmas

Abstract

Phase resolved optical emission spectroscopy (PROES) measurements were combined with measurements of the optical emission intensity (OEI) and electrical characteristics (RF current and voltage, power, and DC bias voltage) as a function of time during the re-ignition of Ar plasmas pulsed at 100 Hz and 10 kHz. The OEI exhibits a large overshoot at the 100 Hz pulsing rate even though no such overshoot is present in any of the electrical characteristics. The OEI overshoot occurs at a point in time when the RF power, voltage, DC bias voltage, and electron density are all smaller than they become later in the glow. PROES measurements in combination with the time resolved electrical characteristics indicate that the heating mechanism for the electrons changes during the time of the overshoot in the OEI from stochastic heating to a combination of stochastic and ohmic heating. This combination appears to enable a more efficient transfer of the electrical energy into the electrons.

Self-consistent simulation of the impedance matching network for single frequency capacitively coupled plasma

“…Indeed, for SF CCP, simplified CCP models already provide a good estimate of the nominal inductor and capacitor values needed, and the variable capacitors anyway have a range of values that allows the user to compensate for any differences compared with theory or any non-ideal effects. However, for some more complex cases like pulsed CCP [17,18] and CCP driven by TVWs [19][20][21][22][23], the design of matching circuit based on these simplified CCP models is hard or even impossible, due to the complexity and non-linearity. Our model thus may provide a feasible solution to these more complicated cases.…”

“…Furthermore, design of the matching networks is one of the key issues in some new CCP configurations, to achieve better control over specific plasma characteristics. Recent efforts include dual-frequency CCP [9,[13][14][15][16], pulsed CCP [17,18] and CCP driven by tailored voltage waveforms (TVWs) [19][20][21][22][23] used in etching at low pressure, as well as CCP at atmosphere [24], or even using CCP as a tunable impedance element for RF systems [25].…”

Science-based, data-driven developments in plasma processing for material synthesis and device-integration technologies

“…The overshoot at reignition reflected the moving heating mechanisms, from stochastic heating to a combination of stochastic and ohmic heating. 63) 2.5.3. Electron heating and other mechanisms.…”

Fundamental study towards a better understanding of low pressure radio-frequency plasmas for industrial applications

“…Previous studies on the ignition process of a pulse modulated CCP mostly focused on the time evolution of the axially resolved or even spatially averaged plasma parameters (e.g., the plasma emission, the electron density and temperature, etc. ), [104,105,[109][110][111][112][113][114] however, a 300 mm-diameter electrode is used in current semiconductor industries and, therefore, time evolution of various plasma parameters is highly radius-dependent during the ignition process in a pulse modulated plasma. Su et al [115] studied, for the first time, the time evolution of discharge parameters at different radial positions over a 300 mm-diameter electrode during the ignition process of a pulse modulated CCP in argon by multi-fold experimental diagnostics.…”