放电参数变化对电感耦合等离子闭式等离子体空间分布特性研究

Study on Spatial Distribution of Inductive Coupled Plasma Closed Plasma with Discharge Parameter Variation

射频电感耦合等离子体(ICP)在实际放电过程中,线圈的构型、电源参数、气压等外部工质条件的变化均会对结果产生较大影响,依靠实验很难得到多外部条件对ICP参数分布的影响机理和规律,因此需要结合仿真和实验的方法进行分析。该文通过建立感性线圈的电磁学有限元模型,分析不同线圈构型下射频电磁场在等离子体内部的空间分布,研究放电参数(线圈构型、功率大小)对等离子体分布影响和E-H模型下放电形态的跳变过程,并观察进入稳定H模式后电源参数的变化规律,为等离子体源的小型化工程应用提供理论基础。实验和仿真计算结果表明:不同线圈匝数在不同功率条件下,电磁场强度变化对等离子功率吸收和功率耦合有较大影响;当工作气压在0~20Pa时,ICP的电子密度呈轴对称分布,随着放电功率、气压的增大,等离子体吸收的功率和电离度也随之增加,其电子密度相应地增大,放电功率的增加会使得环状的等离子体区域随之扩大,在轴向、径向上的分布呈先逐渐增大而后在靠近腔室壁面区域迅速下降。

In the application of inductive coupled plasma(ICP), such as the coil configuration,power supply parameters, pressure and other external conditions are different, it is difficult to get the mechanism of multiple influences on the ICP parameter distribution, This paper combine the simulation and experiment methods, by the establishment of the inductive coil electromagnetic finite element model,analyzing the radio frequency electromagnetic field under different coil configuration in the spatial distribution within the plasma, then we study the influence of discharge parameters(coil configuration,power rate) on the plasma distribution and E-H model dynamic process. By analyzing its discharge parameters to provides a theoretical basis for the miniaturization engineering application of plasma source.The results of experiment and simulation show that:①Under different coil turns and different power rates, the variation of electromagnetic field intensity has a great influence on the plasma power absorption and power coupling.②When pressure the working gas Ar is between 0-20 Pa, the electron density of ICP is axismetrically distributed, with the increase of the discharge power and gas pressure,the absorbed power and ionization degree of the plasma also increased. The distribution of electron density in the axial and radial directions increases gradually and then decreases rapidly near the wall of the chamber.