多电源驱动射频感性耦合等离子体的流体模拟研究

发布时间：2018-06-08 16:27

本文选题：多电源驱动放电 + 射频感性耦合等离子体　；参考：《大连理工大学》2017年博士论文

【摘要】：射频感性耦合等离子体(Inductively oupled Plasma,ICP)具有工作气压低、等离子体密度高、装置简单等优点,在半导体芯片制造工艺中得到了广泛的应用。随着微电子工业的发展,芯片制造工艺中的晶圆尺寸越来越大,刻蚀线宽越来越窄,这对ICP源提出了更高的要求。为满足这些要求,人们提出了由多个电源驱动放电的ICP源,如脉冲偏压的射频ICP源以及双频双线圈的射频ICP源等。相比于传统的ICP源,这些多电源驱动的ICP源的放电机制较为复杂。因此,研究电源参数对等离子体特性的影响,对优化和控制等离子体工艺具有重要意义。在本文中,针对平面线圈型ICP源装置,采用二维流体力学模型系统的研究了外界电源参数对等离子体特性的影响,尤其对等离子体均匀性的影响。在论文第一章中,首先概述了等离子体的分类及低温等离子体的应用,综述了几种典型的射频等离子体源及其放电特点,尤其是系统地阐述了外界参数对ICP均匀性影响的研究进展。最后给出了本文的内容和安排。在第二章中,详细介绍了二维流体力学模型。该模型由流体力学模块和电磁场模块耦合而成。流体力学模块通过求解流体力学方程得到等离子体各宏观物理量,如粒子密度、粒子通量和电子温度等;电磁场模块通过求解麦克斯韦方程组来计算线圈在放电腔室内产生的电磁场的时空分布。此外,本章介绍了所涉及到的边界条件及模拟中使用的数值方法。在第三章中,研究了脉冲直流偏压对射频N2等离子体特性的影响。结果表明:离子密度、感性沉积功率密度及极板表面脉冲周期平均的总离子通量均随偏压幅值的增大而增加;当偏压频率较大时,脉冲开启时间较短,等离子体无法达到稳定状态;当偏压频率较小,脉冲开启时间足够使等离子体达到稳定状态,此时,总离子通量不再受脉冲频率影响。另外,在研究的所有偏压幅值和频率下,当脉冲关闭,极板表面的离子密度先上升,后下降。在第四章中,模拟了双线圈驱动的ICP放电行为,其中工作气体为Ar。结果表明:当内线圈电流一定,减小内线圈的频率时,内线圈附近的角向电场变弱,而外线圈附近的角向电场基本不变;此外,内线圈附近的角向电场随内线圈电流的增大而增加。当内外线圈对放电所起的作用相当时,均可以得到均匀性较好的等离子体。在第五章中,考察了外线圈电流及内线圈的脉冲占空比对Ar/02等离子体均匀性的影响。结果表明,增大外线圈电流时,极板表面脉冲周期平均的正离子通量和O原子密度的径向均匀性变好。在占空比为50%时,极板表面脉冲周期平均的正离子通量的均匀性最好;极板表面脉冲周期平均的O原子密度的径向均匀性随占空比的增加而变差。在第六章,对本文的工作进行了小结,并对进一步开展的模拟研究提出了展望。
[Abstract]:Inductively oupled Plasma (ICP) has the advantages of low working pressure, high plasma density, simple device and so on. It has been widely used in the manufacturing process of semiconductor chip. With the development of microelectronics industry, the size of the wafer in the chip manufacturing process is increasing and the etching line width is narrower and narrower, this is the ICP In order to meet these requirements, to meet these requirements, people have proposed ICP sources, such as pulse bias voltage ICP source and dual frequency dual loop radio frequency ICP source, such as pulse bias voltage source, and so on. Compared to traditional ICP sources, the discharge mechanism of these multi power source ICP sources is more complex. The effect of sex is of great significance to the optimization and control of plasma processes. In this paper, the influence of the external power parameters on the plasma characteristics, especially the plasma uniformity, is studied in the two-dimensional fluid mechanics model system for the planar coil type ICP source. In the first chapter, the plasma plasma is summarized. The classification of body and the application of low temperature plasma are introduced, and several typical RF plasma sources and their discharge characteristics are reviewed. In particular, the research progress on the influence of external parameters on ICP uniformity is systematically expounded. Finally, the contents and arrangements of this paper are given. In the second chapter, the two-dimensional hydrodynamics model is introduced in detail. The mechanical module is coupled with the electromagnetic field module. By solving the fluid mechanics equation, the fluid mechanics module obtains the macroscopic physical quantities of the plasma, such as particle density, particle flux and electron temperature. The electromagnetic field module calculates the space-time distribution of the electromagnetic field produced by the coil in the discharge chamber by solving the Maxwell equation. In this chapter, the boundary conditions involved and the numerical methods used in the simulation are introduced. In the third chapter, the effect of pulsed DC bias on the characteristics of the RF N2 plasma is studied. The results show that the ion density, the perceptual deposition power density and the average total ion flux of the pulse cycle average of the plate surface increase with the increase of the amplitude of the bias voltage. When the bias frequency is large, the pulse opening time is shorter and the plasma can not reach the stable state. When the bias frequency is small, the pulse opening time is sufficient to make the plasma stable. At this time, the total ion flux is no longer affected by the pulse frequency. In addition, when the pulse is closed, the surface of the plate is off at all the bias amplitude and frequency studied. The sub density first rises and then drops. In the fourth chapter, the ICP discharge behavior driven by a double loop is simulated, in which the working gas is Ar. shows that when the current of the inner coil is certain and the frequency of the inner coil is reduced, the angle to the electric field near the inner coil is weakened, and the angle of the angle near the outer coil is basically unchanged; in addition, the angular direction of the electric field near the inner coil is to the electric field. With the increase of the current of the inner coil, a better uniformity of plasma can be obtained when the internal and external coils play an equal role in the discharge. In the fifth chapter, the influence of the outer loop current and the pulse duty ratio of the inner coil on the uniformity of the Ar/02 plasma is investigated. The results show that the surface pulse of the plate surface increases when the outer loop current is increased. The periodic average positive ion flux and the radial uniformity of the O atomic density become better. When the duty ratio is 50%, the uniformity of the positive ion flux on the average pulse cycle of the plate surface is the best, and the radial uniformity of the average O atomic density of the pulse cycle on the plate surface becomes worse with the increase of the duty ratio. In the sixth chapter, the work of this paper is small. Finally, the prospect of further simulation research is put forward.
【学位授予单位】：大连理工大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O53

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