Measurement, Analysis and Control of Waves and Ion Distribution Functions in a Industrial Plasma Processing Tool

几乎所有的半导体器件，如微处理器和存储器芯片，都是通过低温等离子体蚀刻、沉积和清洗硅晶片来制造的。这些过程在由射频电压激励的反应器中进行。尽管这一领域的重要性，这些反应堆内发生的复杂的等离子体传输仍然没有得到很好的理解。该项目涉及洛杉矶的加州大学的实验等离子体物理学家和密歇根大学的计算机建模专家之间的合作，在此期间，这些等离子体的边界层的基本特性将被调查。边界层（称为鞘层）负责加速带电离子进入晶片。此次合作的独特之处在于，它利用了最先进的工业等离子体加工工具，经过修改后，可以结合极其复杂的诊断技术。等离子体用脉冲600 kHz感应线圈产生，并且其上制造器件的硅晶片用多个频率（2和60 MHz）电容偏置，所述多个频率也可以是脉冲的。这项研究将侧重于理解和表征连续和脉冲（电感和电容）等离子体的离子运动和鞘层动力学。离子速度分布函数包含用于激活Si晶片上的蚀刻或沉积的离子的运动和位置的所有信息。使用激光诱导荧光（LIF），将在Ar和Ar/O2和Ar/O2气体混合物中在晶片上方和垂直于晶片的平面中测量其作为鞘层中的空间和时间的函数。它将在数千个空间位置进行测量，空间分辨率小于100微米，时间分辨率为3 ns，以绘制鞘层的动态。发射探针将测量晶圆上方最近发现的波的三维结构。该项目为实验建模的协同合作提供了难得的机会，这将对加工领域产生广泛的影响。密歇根大学开发了计算机模型，将进一步改进并用于分析和解释测量结果。该项目将重点关注不仅具有前沿物理挑战，而且与半导体行业相关的问题。该项目将涉及大量外联活动。我们将与德国波鸿鲁尔大学的等离子体物理小组合作，他们是光学诊断这些等离子体瞬态的领导者。此外，该项目将涉及大量的教育推广活动。Gekelman教授是LAPTAG（洛杉矶物理教师联盟组织）的创始人之一，该组织目前与20多所当地高中和社区大学有联系，其中包括代表性不足的高中学生和教师。LAPTAG在能源部的资助下建立了一个专门的高中等离子体物理实验室（http：//coke.physics.ucla.edu/laptag）。该项目将邀请高中学生和教师参与该项目的研究实习，并将其用作LAPTAG等离子体源。

Nearly all semiconductor devices, such as microprocessors and memory chips, are fabricated in part by low temperature plasmas for etching, deposition and cleaning silicon wafers. These processes are performed in reactors excited by radio frequency voltages. Despite the great importance of this field, the complex plasma transport occurring within these reactors is still not well understood. This project involves a collaboration between experimental plasma physicists at the University of California at Los Angeles and computer modeling experts at the University of Michigan during which fundamental properties of the boundary layers of these plasmas will be investigated. The boundary layers (called sheaths) are responsible for accelerating charged ions into the wafers. The collaboration is unique in that it utilizes a state-of-the-art industrial plasma processing tool modified to incorporate extremely sophisticated diagnostics. The plasma is produced with a pulsed 600 kHz inductive coil and the silicon wafer on which the devices are fabricated is capacitively biased with multiple frequencies (2 and 60 MHz), which can also be pulsed. This research will focus on understanding and characterizing the ion motion and sheath dynamics for both continuous and pulsed (inductive and capacitive) plasmas. The ion velocity distribution function, contains all the information on the motion and location of ions used to activate etching or deposition on the Si wafer. Using laser induced fluorescence (LIF), it will be measured in a plane above and perpendicular to the wafer in Ar and Ar/O2 and Ar/Xe gas mixtures as a function of space and time in the sheath. It will be measured at thousands of spatial locations with a spatial resolution of less than 100 micrometers and time resolution of 3 ns to map out the dynamics of the sheath. Emissive probes will measure the 3-d structure of recently discovered waves above the wafer. This project provides a rare opportunity for a synergistic collaboration in experimental modeling and this will make a broad impact on the processing field. The University of Michigan has developed computer models that will be further improved and applied to the analysis and interpretation of the measurements. The project will focus attention on problems that not only have cutting edge physics challenges, but also are of relevance to the semiconductor industry. The project will involve significant outreach. We will collaborate with the plasma physics groups at Ruhr University in Bochum, Germany who are leaders in optically diagnosing transients in these plasmas. In addition, this project will involve significant educational outreach. Prof. Gekelman is one of the founders of LAPTAG (Los Angeles Physics Teachers Alliance Group), which now has contacts with over twenty local high schools and community colleges, including underrepresented high school students and teachers. LAPTAG has built a dedicated high school plasma physics laboratory (http://coke.physics.ucla.edu/laptag) with funding from the Department of Energy. The outreach will involve high school students and teachers in research internships on this project as well using as the LAPTAG plasma source.