Synergetic effects in a discharge produced by a dual frequency–dual antenna large-area ICP source

Abstract

Using an RF-compensated Langmuir probe, plasma parameters have been investigated in a discharge produced by a dual frequency-dual antenna: the next generation of large-area inductively coupled plasma (ICP) sources. The ICP source was made of two concentric spiral copper coils embedded into each other. The inner and outer coils were energized by RF frequencies of 2 and 13.56 MHz, respectively. The discharge was operated at an average pressure of 10 mTorr in an argon gas environment. The probe was positioned at a fixed location of 70 mm from the source and 160 mm from the centre of the ICP source to measure the plasma parameters. However, for discharge uniformity measurements, the probe position was varied from the centre of the discharge to 200 mm towards the edge. It was found that the ion density distribution over the wafer varies with RF power ratio (P 2 MHz /P 13.56 MHz). For a fixed power at 13.56 MHz (P 13.56 MHz), the plasma density increases very slowly with P 2 MHz , when P 2 MHz < 400 W; however, the plasma density increases rapidly when P 2 MHz > 400 W. The electron temperature and plasma potential measurements show decreasing trends with increasing P 2 MHz at constant P 13.56 MHz. The ion density measurements over the substrate show that good discharge uniformity (∼4%) can be achieved by adjusting the RF power ratio (P 2 MHz /P 13.56 MHz).

Plasma dynamics in a discharge produced by a pulsed dual frequency inductively coupled plasma source

“…10 It has also been demonstrated that, when using this type of plasma source, the ion and electron energy distribution could be efficiently modulated by varying the power ratio of the two frequencies. 11,12 Pulsing this plasma source could provide further advantages, since pulsed plasma has several benefits over continuous wave (CW) plasma, such as low charging damage, improvement of film quality in deposition, variation of ion species, and higher plasma density at the same average input power.…”

Transient plasma potential in pulsed dual frequency inductively coupled plasmas and effect of substrate biasing

“…Recently, a new type of ICP source based on utilizing dual-antenna, dual frequency concept has been proposed and a discharge non-uniformity of ∼4% has been achieved over the substrate area, 450 mm in diameter. 18 By using this kind of plasma source, it has also been demonstrated that ion and electron energy distribution could be efficiently modulated by varying two power ratio. 19,20 A further advantage, such as more flexibility to control the discharge parameters, could be added, if this source is used in a pulsed mode.…”

“…19,20 A further advantage, such as more flexibility to control the discharge parameters, could be added, if this source is used in a pulsed mode. 18 Pulsed plasmas show significant potential to meet the majority of the scaling challenges and offer new tuning knobs (pulse frequency, duty cycle, and optional phase lag between source and bias pulses) that enhance independent control of plasma conditions (in particular, ion bombardment energy and plasma chemical composition. Several pulsing modes can be envisaged.…”

Characteristics of a dual‐radio‐frequency cylindrical inductively coupled plasma

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The plasma parameters such as electron density, effective electron temperature, plasma potential, and uniformity are investigated in a new dual-frequency cylindrical inductively coupled plasma (ICP) source operating at two frequencies (2 and 13.56 MHz) and two antennas (a two-turn high-frequency antenna and a six-turn low-frequency (LF) antenna). inductively coupled plasma (ICP) sources, [4][5][6][7] capacitively coupled plasma (CCP) sources, [8,9] electron cyclotron resonance (ECR) sources, [10] and microwave plasma sources, [11] are being extensively investigated by many researchers. Moreover, the plasma uniformity can be improved by adjusting the LF power.

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