Determination of Plasma Parameters in a Dual-Frequency Capacitively Coupled CF<sub>4</sub>Plasma Using Optical Emission Spectroscopy

Liu, Wen-Yao; Zhu, Ai‐Min; Li, Xiaosong; Zhao, Guo-Li

doi:10.1088/1009-0630/15/9/10

Cited by 2 publications

(1 citation statement)

References 30 publications

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“…If we assume that the atomic fluorine density directly depends on I(F), this shows that a relationship exists between the density of the atomic fluorine and the SiN :H etch rate. In fact, a number of recent studies have produced similar results to utilize a relation between the OES intensity and plasma density [26][27][28].…”

Section: Discussion When Sin :H Film Is Etched Using Fluorinebased Gmentioning

confidence: 90%

A Study of Parameters Related to the Etch Rate for a Dry Etch Process Using NF₃/O₂and SF₆/O₂

Park

Lee

et al. 2014

Advances in Materials Science and Engineering

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The characteristics of the dry etching of SiN :H thin films for display devices using SF 6 /O 2 and NF 3 /O 2 were investigated using a dual-frequency capacitively coupled plasma reactive ion etching (CCP-RIE) system. The investigation was carried out by varying the RF power ratio (13.56 MHz/2 MHz), pressure, and gas flow ratio. For the SiN :H film, the etch rates obtained using NF 3 /O 2 were higher than those obtained using SF 6 /O 2 under various process conditions. The relationships between the etch rates and the usual monitoring parameters-the optical emission spectroscopy (OES) intensity of atomic fluorine (685.1 nm and 702.89 nm) and the voltages and -were investigated. The OES intensity data indicated a correlation between the bulk plasma density and the atomic fluorine density. The etch rate was proportional to the product of the OES intensity of atomic fluorine ( (F)) and the square root of the voltages (√ ℎ + ) on the assumption that the velocity of the reactive fluorine was proportional to the square root of the voltages.

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Section: Discussion When Sin :H Film Is Etched Using Fluorinebased Gmentioning

confidence: 90%

A Study of Parameters Related to the Etch Rate for a Dry Etch Process Using NF₃/O₂and SF₆/O₂

Park

Lee

et al. 2014

Advances in Materials Science and Engineering

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Impact of plasma operating conditions on the ion energy and angular distributions in dual-frequency capacitively coupled plasma reactors using CF4 chemistry

Ducluzaux,

Ristoiu,

Cunge

et al. 2024

Journal of Vacuum Science &Amp; Technology A

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A two-dimensional hybrid model is used to simulate an industrial dual-frequency capacitively coupled plasma reactor working at closely spaced frequencies (13.56–40.68 MHz) in pure CF4 chemistry. The goal is to understand how plasma operating conditions (pressure, low-frequency and high-frequency RF powers, and chamber wall conditions) influence critical etching parameters such as the ion energy and angular distribution (IEAD) and the ion flux at the wafer. In base case conditions, the ionic and radical composition at the center of the plasma is analyzed, revealing CF3+ and F− as the primary ions, and F, CF, CF3, CF2, and F2 as the predominant radicals (by decreasing density). The impact of the surface recombination coefficient of F radicals into F2 at the reactor walls, γ(rec,F > F2), is then explored; it is found that increasing γ(rec,F > F2) has a strong impact on the final plasma composition, decreasing CF and F densities while increasing CF3, CF2, and F densities, which highlights the importance of properly considering wall conditions in CF-based plasmas simulation. The IEAD at the wafer is then characterized, showing that the total IEAD shape is affected by the plasma ion composition: heavy ions such as CF3+ (69 amu) form the core of the distribution while lighter species such as F+ (19 amu) form the wing of the distribution due to their lower mass. The low frequency (LF) power (100–900 W) is shown to substantially modify the ion energy distribution function (IEDF) owing to sheath voltage changes, but to also marginally increase the ion flux at the wafer. Conversely, the high-frequency (HF) power (100–1500 W) strongly impacts the ion flux at the wafer due to HF voltage fluctuations, while the IEDF remains mostly unaffected. This study also reveals some coupling between the effects of the LF (13.56 MHz) and HF (40.68 MHz) power, a phenomenon attributable to their proximity in frequency which should not be neglected. Finally, increasing the pressure from 30 to 200 mTorr is found to increase the electronegativity by a factor 4 and to strongly impact the plasma structure, primarily due to variations in ion mobility; it also widens the ion angular spread, potentially influencing etch uniformity. Notably, higher pressures exceeding 100 mTorr result in a decrease in the average ion density and the emergence of a low-energy peak in the ion energy distribution, attributed to charge exchange collisions.

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Determination of Plasma Parameters in a Dual-Frequency Capacitively Coupled CF₄Plasma Using Optical Emission Spectroscopy

Cited by 2 publications

References 30 publications

A Study of Parameters Related to the Etch Rate for a Dry Etch Process Using NF₃/O₂and SF₆/O₂

A Study of Parameters Related to the Etch Rate for a Dry Etch Process Using NF₃/O₂and SF₆/O₂

Impact of plasma operating conditions on the ion energy and angular distributions in dual-frequency capacitively coupled plasma reactors using CF4 chemistry

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Determination of Plasma Parameters in a Dual-Frequency Capacitively Coupled CF4Plasma Using Optical Emission Spectroscopy

Cited by 2 publications

References 30 publications

A Study of Parameters Related to the Etch Rate for a Dry Etch Process Using NF3/O2and SF6/O2

A Study of Parameters Related to the Etch Rate for a Dry Etch Process Using NF3/O2and SF6/O2

Impact of plasma operating conditions on the ion energy and angular distributions in dual-frequency capacitively coupled plasma reactors using CF4 chemistry

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Product

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Determination of Plasma Parameters in a Dual-Frequency Capacitively Coupled CF₄Plasma Using Optical Emission Spectroscopy

A Study of Parameters Related to the Etch Rate for a Dry Etch Process Using NF₃/O₂and SF₆/O₂

A Study of Parameters Related to the Etch Rate for a Dry Etch Process Using NF₃/O₂and SF₆/O₂