Ion energy and angular distributions in planar Ar/O<sub>2</sub> inductively coupled plasmas: hybrid simulation and experimental validation

Zhang, Yuru; Zhao, Zhuanzhuan; Xue, Chan; Gao, Fei; Wang, You‐Nian

doi:10.1088/1361-6463/ab1dd3

Cited by 12 publications

(7 citation statements)

References 35 publications

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“…15 In addition to the difficulties that make understanding thermal oxidation challenging, the interaction of metal surfaces with the plasma is unique in having energetic particles impacting the surface. 16 The particles used in the corresponding experimental process (the "target process") have kinetic energies on the order of 10 eV, 17,18 high above those possible from thermal fluctuations, yet too low to cause ion implantation or sputter the substrate atoms. Unlike the case for higher energies (>1 keV) where simple screened Coulomb potentials coupled to binary collision approximation give very reasonable results, here an accurate description of the potential energy surface is still relevant, since the kinetic energy is within an order of magnitude of the strength of a typical chemical bond.…”

Section: Introductionmentioning

confidence: 99%

Plasma Oxidation of Copper: Molecular Dynamics Study with Neural Network Potentials

Xia

Sautet

2022

ACS Nano

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The formation of thin oxide films is of significant scientific and practical interest. In particular, the semiconductor industry is interested in developing a plasma atomic layer etching process to pattern copper, replacing the dual Damascene process. Using a nonthermal oxygen plasma to convert the metallic copper into copper oxide, followed by a formic acid organometallic reaction to etch the copper oxide, this process has shown great promise. However, the current process is not optimal because the plasma oxidation step is not self-limiting, hampering the degree of thickness control. In the present study, a neural network potential for the binary interaction between copper and oxygen is developed and validated against first-principles calculations. This potential covers the entire range of potential energy surfaces of metallic copper, copper oxides, atomic oxygen, and molecular oxygen. The usable kinetic energy ranges from 0 to 20 eV. Using this potential, the plasma oxidation of copper surfaces was studied with large-scale molecular dynamics at atomic resolution, with an accuracy approaching that of the first principle calculations. An amorphous layer of CuO is formed on Cu, with thicknesses reaching 2.5 nm. Plasma is found to create an intense local heating effect that rapidly dissipates across the thickness of the film. The range of this heating effect depends on the kinetic energy of the ions. A higher ion energy leads to a longer range, which sustains faster-than-thermal rates for longer periods of time for the oxide growth. Beyond the range of this agitation, the growth is expected to be limited to the thermally activated rate. High-frequency, repeated ion impacts result in a microannealing effect that leads to a quasicrystalline oxide beneath the amorphized layer. The crystalline layer slows down oxide growth. Growth rate is fitted to the temperature gradient due to ioninduced thermal agitations, to obtain an apparent activation energy of 1.0 eV. A strategy of lowering the substrate temperature and increasing plasma power is proposed as being favorable for more self-limited oxidation.

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Section: Introductionmentioning

confidence: 99%

Plasma Oxidation of Copper: Molecular Dynamics Study with Neural Network Potentials

Xia

Sautet

2022

ACS Nano

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“…The ion-neutral collisions included in this work are the same as in [19,73]. When all the particles reach the biased electrode, the IEDF F (ε i ) and ion angular distribution function F (Θ i ) are calculated from the statistics [21]…”

Section: Ion Monte Carlo Collision Modelmentioning

confidence: 99%

“…On the other hand, the ICP power also has an impact on the voltage drop across the bias sheath, and thereby affects the ion energy distribution functions (IEDFs) [11,[15][16][17][18][19][20][21]. Schulze et al [11] presented the decline of the sheath voltage at higher inductive power, which was caused by the increasing ion flux.…”

Section: Introductionmentioning

confidence: 99%

“…Results provided by different numerical methods [17][18][19][20] indicated that the ion energy separation width of IEDFs became wider with the increase of ICP power. Zhang et al [21] employed a hybrid model to investigate the influence of ICP power in Ar/O 2 plasmas, and their results suggested that both the high and low energy peaks in IEDFs moved towards lower energy at high ICP power. Thus, it is concluded that independent modulation of the ion flux and ion energy in biased ICP discharges is very difficult to achieve.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of the dual-frequency bias effect on inductively coupled Cl₂ plasmas by hybrid simulation

Tong

Zhao

Zhang

et al. 2023

J. Phys. D: Appl. Phys.

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In the etching process, a bias source is usually applied to the bottom electrode in inductively coupled plasmas (ICPs) to achieve independent control of the ion flux and ion energy. In this work, a hybrid model, which consists of a global model combined bi-directionally with a fluid sheath model, is employed to investigate the dual-frequency (DF) bias effect on the inductively coupled Cl2plasmas under different pressures. The results indicate that the DC self-bias voltage developed on the biased electrode is approximately a linear function of the phase shift between the fundamental frequency and its second harmonic, and the value only varies slightly with pressure. Therefore, the ion energy on the bottom electrode can be modulated efficiently by the bias voltage waveform, i.e., the fluctuation of the ion energy with phase shift is about 40% for all pressures investigated. Besides, the ion energy and angular distribution functions (IEADFs) in DF biased inductive discharges is complicated, i.e., the IEADFs exhibits a four-peak structure under certain phase shift values. Although the species densities and ion fluxes also evolve with phase shift, the fluctuations are less obvious, especially for Cl2+ ions at low pressure. In conclusion, the independent control of the ion energy and ion flux are realized in DF biased ICPs, and the results obtained in this work are of significant importance for improving the etching process.

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“…Because the distribution of plasma characteristics is vital for controlling the process of semiconductor etching, it is of great interest to elucidate the effect of bias on the plasma distributions. Therefore, in this study, the multi-physics analysis for plasma sources-ICP (MAPS-ICP) solver [17][18][19][20][21] composed of a fluid module and a sheath module [22,23] is employed to investigate the effects of single-frequency and dual-frequency bias on the plasma characteristics at different values of ICP source power. Our results provide a useful insight into the effect of source power, which can be used for optimizing the plasma processing techniques.…”

Section: Introductionmentioning

confidence: 99%

Effect of radio frequency bias on plasma characteristics of inductively coupled argon discharge based on fluid simulations*

et al. 2020

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A fluid model is employed to investigate the effect of radio frequency bias on the behavior of an argon inductively coupled plasma (ICP). In particular, the effects of ICP source power, single-frequency bias power, and dual-frequency bias power on the characteristics of ICP are simulated at a fixed pressure of 30 mTorr (1 Torr = 1.33322 × 102 Pa). When the bias frequency is fixed at 27.12 MHz, the two-dimensional (2D) plasma density profile is significantly affected by the bias power at low ICP source power (e.g., 50 W), whereas it is weakly affected by the bias power at higher ICP source power (e.g., 100 W). When dual-frequency (27.12 MHz/2.26 MHz) bias is applied and the sum of bias powers is fixed at 500 W, a pronounced increase in the maximum argon ion density is observed with the increase of the bias power ratio in the absence of ICP source power. As the ratio of 27.12-MHz/2.26-MHz bias power decreases from 500 W/0 W to 0 W/500 W with the ICP source power fixed at 50 W, the plasma density profiles smoothly shifts from edge-high to center-high, and the effect of bias power on the plasma distribution becomes weaker with the bias power ratio decreasing. Besides, the axial ion flux at the substrate surface is characterized by a maximum at the edge of the substrate. When the ICP source power is higher, the 2D plasma density profiles, as well as the spatiotemporal and radial distributions of ion flux at the substrate surface are characterized by a peak in the reactor center, and the distributions of plasma parameters are negligibly affected by the dual-frequency bias power ratio.

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Ion energy and angular distributions in planar Ar/O₂ inductively coupled plasmas: hybrid simulation and experimental validation

Cited by 12 publications

References 35 publications

Plasma Oxidation of Copper: Molecular Dynamics Study with Neural Network Potentials

Plasma Oxidation of Copper: Molecular Dynamics Study with Neural Network Potentials

Investigation of the dual-frequency bias effect on inductively coupled Cl₂ plasmas by hybrid simulation

Effect of radio frequency bias on plasma characteristics of inductively coupled argon discharge based on fluid simulations*

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Ion energy and angular distributions in planar Ar/O2 inductively coupled plasmas: hybrid simulation and experimental validation

Cited by 12 publications

References 35 publications

Plasma Oxidation of Copper: Molecular Dynamics Study with Neural Network Potentials

Plasma Oxidation of Copper: Molecular Dynamics Study with Neural Network Potentials

Investigation of the dual-frequency bias effect on inductively coupled Cl2 plasmas by hybrid simulation

Effect of radio frequency bias on plasma characteristics of inductively coupled argon discharge based on fluid simulations*

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Product

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Ion energy and angular distributions in planar Ar/O₂ inductively coupled plasmas: hybrid simulation and experimental validation

Investigation of the dual-frequency bias effect on inductively coupled Cl₂ plasmas by hybrid simulation