Improving discharge uniformity of industrial-scale very high frequency plasma sources by launching a traveling wave

Chen, Hsin‐Liang; Tu, Yen-Cheng; Hsieh, Cheng-Chang; Lin, Deng-Lain; Chang, Chin-Jung; Leou, Keh-Chyang

doi:10.1016/j.cap.2016.03.011

Cited by 3 publications

(2 citation statements)

References 28 publications

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“…At a lower operating gas pressure (50 mTorr), the maximum of the density profile is found in the tile-centre, whereas, tiletile boundary density is lower. The plasma non-uniformity is calculated by ((n max − n min ) / (n max + n min )) × 100, where n max and n min are maximum and minimum electron density respectively [43,44]. It is shown in figure 4, on increasing RF power, the plasma uniformity is significantly improved.…”

Section: Plasma Densitymentioning

confidence: 99%

Investigation of plasma uniformity, rotational and vibrational temperature in a 162 MHz multi-electrode capacitive discharge

Sirse

Harvey

Gaman

et al. 2020

J. Phys. D: Appl. Phys.

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The plasma density (n e ) profile, rotational (T rot ) and vibrational (T vib ) temperatures, and their dependence on the RF power (500-1500 W) and gas pressure (50-500 mTorr) is investigated in a high to very high frequency (VHF) (162 MHz) capacitively coupled nitrogen plasma excited by a multi-tile electrode (tiles) system. The density profile is measured in the mid-plane of the discharge using a resonance hairpin probe, and the rotational and vibrational temperatures are measured at both tile centre and tile-tile boundary using optical emission spectroscopy. It is observed that the plasma density increases monotonically with a rise in RF power and decreases with an increase in the operating gas pressure. At a low gas pressure (50 mTorr), plasma density profile shows a maximum at the tile centre and a minimum at the tile-tile boundary, whereas, at high gas pressure tile-edge effects are observed. Measured rotational temperature (∼350-450 K) is slightly above room temperature for both positions and independent of RF power and operating gas pressure. Vibrational temperature is in the range of ∼6500-9400 K, and increases with RF power, analogue to the plasma density. It is noticed that the plasma uniformity can be substantially improved, to better than 90%, by changing the power-pressure matrix. A large difference between measured vibrational and rotational gas temperature suggests that the plasma produced by VHF multi-tile electrode is under highly non-equilibrium condition and thus highly efficient to produce unique gas phase chemistry.

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Section: Plasma Densitymentioning

confidence: 99%

Investigation of plasma uniformity, rotational and vibrational temperature in a 162 MHz multi-electrode capacitive discharge

Sirse

Harvey

Gaman

et al. 2020

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

show abstract

“…Both experimental [19][20][21] and numerical [22][23][24] research indicated that by varying the phase difference between the two sources applied to the top and bottom electrodes, i.e., the so-called phase-shift control, the plasma currents redistributed and therefore the plasma uniformity could be optimized. Moreover, Chen et al pointed out that the plasma nonuniformity decreased significantly by launching a traveling wave, which was generated by the superposition of two standing waves with the same amplitude and out of phase by 90 • in space and time [25][26][27]. Bera et al introduced the electric potential and the magnetic vector potential to calculate the ES field and the EM field, respectively, and they presented different electron density distributions with various combinations of powers at 60 MHz and 180 MHz [28].…”

Section: Introductionmentioning

confidence: 99%

How to address the issue of uniformity in large area capacitively coupled plasmas? A modeling investigation

Zhang

Wang

2020

Plasma Sources Sci. Technol.

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Recently, the electrical asymmetry effect (EAE) has been proven effective not only in separate control of the ion energy and ion flux, but also in modulation of the plasma radial uniformity. Since no major change in reactor constructions is required, this method is promising and of significant importance in the plasma industry. In this work, a two-dimensional electromagnetic fluid model is employed to investigate the influence of the EAE on the plasma density distribution under various voltages (i.e., the peak-to-peak voltage V 0 equals to 33 V, 56 V and 100 V) and pressures (i.e., 50 mTorr, 200 mTorr and 750 mTorr), in H 2 capacitively coupled plasma (CCP) discharges sustained by multiple consecutive harmonics. The results indicate that at V 0 = 33 V or 750 mTorr, the plasma density is characterized by a broad maximum at the radial center, and the effectiveness of the EAE on the modulation of the plasma radial uniformity is limited. When V 0 becomes higher, the plasma distribution varies obviously by adjusting the phase shift of the fundamental frequency θ 1 . For instance, when θ 1 increases from 0 to 2π at V 0 = 56 V, the plasma density shifts from uniform over center-high to uniform. Moreover, at V 0 = 100 V, the best uniformity is observed at θ 1 = π. When the pressure decreases to 50 mTorr, although the uniformity varies significantly with θ 1 , the plasma density stays low, which may not be welcomed in the plasma processing. Different influences of the EAE on the plasma radial uniformity can be understood by examining the electron heating induced by the sheath expansion and the electric field reversal under various discharge conditions. The results obtained in this work could help us to have a better understanding of the EAE on the plasma radial uniformity, which would be useful to improve the plasma processing in large area CCP reactors.

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Experimental and Numerical Investigation Into the Plasma Treatment and Chip Delamination in Semiconductor Packaging

Pai

Lin

2020

IEEE Trans. Plasma Sci.

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Improving discharge uniformity of industrial-scale very high frequency plasma sources by launching a traveling wave

Cited by 3 publications

References 28 publications

Investigation of plasma uniformity, rotational and vibrational temperature in a 162 MHz multi-electrode capacitive discharge

Investigation of plasma uniformity, rotational and vibrational temperature in a 162 MHz multi-electrode capacitive discharge

How to address the issue of uniformity in large area capacitively coupled plasmas? A modeling investigation

Experimental and Numerical Investigation Into the Plasma Treatment and Chip Delamination in Semiconductor Packaging

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