Effects of process parameters and chamber structure on plasma uniformity in a large-area capacitively coupled discharge

Enhancing plasma uniformity can be achieved by modifying coil and chamber structures in radio frequency inductively coupled plasma (ICP) to meet the demand for large-area and uniformly distributed plasma in industrial manufacturing. This study utilized a two-dimensional self-consistent fluid model to investigate how different coil configurations and chamber aspect ratios affect the radial uniformity of plasma in radio frequency ICP. The findings indicate that optimizing the radial spacing of the coil enhances plasma uniformity but with a reduction in electron density. Furthermore, optimizing the coil within the ICP reactor, using the interior point method in the Interior Point Optimizer significantly enhances plasma uniformity, elevating it from 56% to 96% within the range of the model sizes. Additionally, when the chamber aspect ratio k changes from 2.8 to 4.7, the plasma distribution changes from a center-high to a saddle-shaped distribution. Moreover, the plasma uniformity becomes worse. Finally, adjusting process parameters, such as increasing source power and gas pressure, can enhance plasma uniformity. These findings contribute to optimizing the etching process by improving plasma radial uniformity.

Section: Resultsmentioning

confidence: 99%

Effect of coil and chamber structure on plasma radial uniformity in radio frequency inductively coupled plasma

ZHAO 赵,

ZHOU 周,

GAO 高

et al. 2024

“…Radiofrequency (RF) capacitively coupled plasmas (CCPs) are widely used in the semiconductor industry, for example in dielectric etching and thin film deposition [1], because of their advantages of producing a high ion energy [2][3][4][5] and a uniform large-area plasma [6][7][8][9]. Argon, as an inert gas, has simple chemical reactions and is cost-effective, and is thus often used in laboratories for studying the general properties of gas discharges [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Effect of a negative DC bias on a capacitively coupled Ar plasma operated at different radiofrequency voltages and gas pressures

XIANG 相,

WANG 王,

LIU 刘

et al. 2024

Effect of a negative direct current (DC) bias,|Vdc|, on the electrical parameters and discharge mode is investigated experimentally in a radio frequency (RF) capacitively coupled Ar plasma operated at different RF voltage amplitudes and different gas pressures. The electron density is measured by using a hairpin probe and the spatio-temporal distribution of electron-impact excitation rate is determined by phase-resolved optical emission spectroscopy, and the electrical parameters are obtained based on the waveforms of the electrode voltage and the plasma current measured by a voltage and current probe. It was found that at a low |Vdc|, i.e., in α mode, the electron density and the RF current decline with increasing |Vdc|, and meanwhile, the plasma impedance becomes more capacitive, due to a widened sheath. So, the RF power deposition is suppressed. When |Vdc| exceeds a certain value, the plasma turns into α-γ hybrid mode (or the discharge becomes dominated by the γ-mode), manifesting a drastically-growing electron density and a moderately-increasing RF current. Meanwhile, the plasma impedance becomes more resistive, so the RF power deposition is enhanced with |Vdc|. Besides, we found that the electrical parameters show similar dependence on |Vdc| at different RF voltages, and the α-γ mode transition occurs at a lower |Vdc| at a higher RF voltage. By increasing the pressure, the plasma impedance becomes more resistive, so the RF power deposition and the electron density are enhanced. Especially, the α-γ mode transition tends to occur at a lower |Vdc| with the increase of the pressure.

“…Previous studies have shown that manipulating the discharge parameters in CCP discharges is able to improve plasma uniformity. Liang et al [17] utilized a two-dimensional self-consistent electrostatic fluid model to examine the radial uniformity of plasma in capacitively coupled nitrogen discharges operated at 60 MHz. They discovered that reducing the radio frequency (RF) power effectively decreases the electron density at the plasma edge, thus mitigating the edge effect in the CCP chamber.…”

Section: Introductionmentioning

confidence: 99%

Customized modulation on plasma uniformity by non-uniform magnetic field in capacitively coupled plasma

WANG 王,

ZHANG 张,

MA 马

et al. 2024

A two-dimensional fluid model based on COMSOL Multiphysics is developed to investigate the modulation of static magnetic field on plasma homogeneity in a Capacitively Coupled Plasma chamber. To generate a static magnetic field, direct current is applied to a circular coil located at the top of the chamber. By adjusting the magnetic field's configuration, which is done by altering the coil current and position, both the plasma uniformity and density can be significantly modulated. In the absence of the magnetic field, the plasma density exhibits an inhomogeneous distribution characterized by higher values at the plasma edge and lower values at the center. The introduction of a magnetic field generated by coils results in a significant increase in electron density near the coils. Furthermore, an increase in the sets of coils improves the uniformity of the plasma. By flexibly adjusting the positions of the coils and the applied current, a substantial enhancement in overall uniformity can be achieved. These findings demonstrate the feasibility of using this method for achieving uniform plasma densities in industrial applications.