电容耦合的抑制对感应耦合放电等离子体的影响

感应耦合等离子体(ICP)是微电子工业刻蚀高精度沟槽结构的首选高密度等离子体源.研究ICP的电特性与等离子体电学参量的变化显得非常重要.本文中,在平板型ICP源的感应线圈和介质窗口之间,使用了对称、均匀、呈辐射状的法拉第屏蔽板.结果表明,屏蔽板的使用不仅极大地降低了干扰等离子体参量测量的等离子体射频电位,而且也降低了线圈中的放电电流和等离子体中的轴向微分磁场信号强度,但Ar等离子体的发射光谱表明,法拉第屏蔽的采用对等离子体功率吸收的影响不大.对测量信号中出现的高次谐波行为也做了定性的讨论.     

Investigation of Capacitively Coupled Argon Plasma Driven by Dual-Frequency with Different Frequency Configurations

Low pressure argon dual-frequency （DF） capacitively coupled plasma （CCP） is generated by using different frequency configurations, such as 13.56/2, 27/2, 41/2, ...     

碳氟感应耦合等离子体的SiO2介质刻蚀的研究

使用感应耦合等离子体技术,通过改变源气体流量比R(R=[C4F8]/{[C4F8] [Ar]})、射频源功率、自偏压等条件进行了SiO2介质刻蚀实验研究。碳氟等离子体的特征由朗谬探针和发射光谱技术来表征。结果表明,SiO2的刻蚀速率随放电源功率和射频自偏压的增大而单调上升,与R的关系则存在R=8%处的刻蚀速率峰值。C2基团的发射谱线强度随R的变化类似于SiO2刻蚀速率对R的依赖关系,对此给出了解释。在此基础上,对SiO2介质光栅进行了刻蚀。结果显示,在较大的R及自偏压等条件下,刻蚀后的槽形呈轻微的锥形图案,同时光刻胶掩膜图形出现分叉。结合扫描电镜技术对此进行了分析,认为光刻胶表面与侧面的能量传递和聚合物再沉积是导致出现上述现象的原因。     

Effect of gas pressure on ion energy at substrate side of Ag target radio-frequency and very-high-frequency magnetron sputtering discharge

The effect of gas pressure on ion energy distribution at the substrate side of Ag target radio-frequency (RF) and very-high-frequency (VHF) magnetron sputtering discharge was investigated. At lower pressure, the evolution of maximum ion energy (E) with discharge voltage (V) varied with the excitation frequency, due to the joint contribution of the ion generation in the bulk plasma and the ion movement across the sheath related to the ion transit sheath time τi and RF period τ_RF. At higher pressure, the evolution of E–V relationships did not vary with the excitation frequency, due to the balance between the energy lost through collisions and the energy gained by acceleration in the electric field. Therefore, for RF and VHF magnetron discharge, lower gas pressure can have a clear influence on the E–V relationship.     

Abnormal Enhancement of N2+ Emission Induced by Lower Frequency in N2 Dual-Frequency Capacitively Coupled Plasmas

Nitrogen dual-frequency capacitively coupled plasmas(DF-CCPs) with different frequency configurations,i.e.,60/2 MHz and 60/13.56 MHz,are investigated by means of optical emission spectroscopy(OES) and a floating double probe.The excited nitrogen molecule ion N + 2(B) is monitored by measuring the emission intensity of the(0,0) bandhead of the first negative system(FNS) at 391.44 nm.It is shown that in the discharge with 60/13.56 MHz,the N + 2 emission intensity decreases with the increase in pressure.In the discharge with 60/2 MHz,however,an abnormal enhancement of N + 2 emission at higher pressure is observed when a higher power of 2 MHz is added.Variation in the ion density shows a similar dependence on the gas pressure.This indicates that in the discharge with 60/2 MHz there is a mode transition from the alpha to gamma type when a higher power of 2 MHz is added at high pressures.Combining the measurements using OES and double probe,the influence of low frequency on the discharge is investigated and the excitation route of the N + 2(B) state in the discharge of 60/2 MHz is also discussed.