Systematic Studies of Plasma Reactions on Dynamic Surfaces, Using a Novel Rotating Substrate

使用新型旋转基底对动态表面上的等离子体反应进行系统研究

• 批准号: 0650992
• 负责人: Vincent Donnelly
• 金额: --
• 依托单位: University of Houston
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-01 至 2010-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0650992&HistoricalAwards=false
• 关键词: Systematic; Studies; Plasma; Reactions; Dynamic

Award: CBET-0650992Title: Systematic Studies of Plasma Reactions on Dynamic Surfaces Using a Novel Rotating SubstratePrincipal Investigator: Vincent M. DonnellyInstitution: University of Houston, Houston TXA novel approach will be taken to study the important interactions of gaseous plasmas with plasma reactor walls. Plasma discharges are used to deposit thin films, and most importantly, to etch fine features in silicon integrated circuits. Control of these plasma etching processes will be critical in enabling future top-down nano-technology in the coming decades. Many of the scientific and technological challenges in understanding and controlling plasma etching and deposition processes involve the complex chemistry occurring at the plasma/reactor wall boundary. Reactant radical species such as chlorine atoms that are generated in the plasma by collisions of energetic plasma electrons with the process gas chlorine (Cl2) are required to promote selective and directional etching of electronic materials including silicon. These reactants reach a concentration in the plasma that is established in part by loss reactions at the plasma-wall boundary, which produce less reactive products. A good example would be the formation of Cl2 from combination of two Cl atoms. The rate of surface reactions depends on the nature of the surface, which in turn depends on the composition of the materials being etched and the duration of the process. Consequently, reactant concentrations drift over time, making it difficult to control plasma processes. A basic knowledge of even simple wall reactions is mostly lacking, in large part because of the challenge in applying reliable analytical methods under hostile plasma conditions. Here we will bring the established surface-science diagnostic techniques of mass spectrometry and Auger electron spectroscopy to the plasma environment, allowing reactions at the plasma-wall boundary to be identified and studied. This is accomplished by substituting a cylindrical substrate for a small, hollow section of the reactor wall. A chamber housing these diagnostic tools is sealed to the other side of the reactor wall. The substrate is rotated rapidly; consequently, a portion of its surface is periodically in the plasma and then faces the diagnostic probe a very short time thereafter. Large vacuum pumps attached to the hollow plasma wall and on the diagnostics chamber remove the gas that leaks from the plasma. In this manner, the plasma gas and charged species are prevented from distorting the diagnostic methods, and the products formed on and evolving from the plasma wall can be isolated and identified. The time between plasma exposure and analysis can also be varied by changing the substrate rotation speed, allowing reaction rates to be extracted. The proposed work will yield basic knowledge of plasma surface interactions and will also provide critical information for improving control of advanced plasma processes that will be called upon for fabrication of future nano-devices.The proposed work will provide rich scientific and educational payoffs, as well as technological advances. The basic knowledge that will emerge from these studies, and in particular, the new method for isolating such complex reactions has broad implications for and potential impact on diverse areas including wall reactions in plasma fusion reactors, catalysis, combustion, and atmospheric chemistry, as well as basic surface science. Several outreach activities are planned, including a collaboration with the Coalition for Plasma Science to increase public awareness for societal benefits of plasma processing of semiconductors.

奖项：CBET-0650992标题：使用新型旋转基板对动态表面上的等离子体反应进行系统研究主要研究员：Vincent M.Donnelly机构：休斯顿大学，德克萨斯州休斯顿将采用新颖的方法来研究气态等离子体与等离子体反应器壁的重要相互作用。 等离子放电用于沉积薄膜，最重要的是，用于蚀刻硅集成电路中的精细特征。 对这些等离子体蚀刻过程的控制对于未来几十年实现自上而下的纳米技术至关重要。理解和控制等离子体蚀刻和沉积过程的许多科学和技术挑战涉及等离子体/反应器壁边界处发生的复杂化学反应。 需要反应自由基物质，例如通过高能等离子体电子与工艺气体氯 (Cl2) 碰撞而在等离子体中产生的氯原子，以促进包括硅在内的电子材料的选择性和定向蚀刻。 这些反应物在等离子体中达到一定浓度，该浓度部分是通过等离子体壁边界处的损失反应而建立的，从而产生较少的反应产物。 一个很好的例子是两个 Cl 原子结合形成 Cl2。 表面反应的速率取决于表面的性质，而表面的性质又取决于被蚀刻材料的成分和过程的持续时间。 因此，反应物浓度随着时间的推移而漂移，使得等离子体过程的控制变得困难。 即使是简单的壁反应的基本知识也大多缺乏，很大程度上是因为在恶劣的等离子体条件下应用可靠的分析方法面临挑战。 在这里，我们将把现有的质谱和俄歇电子能谱等表面科学诊断技术引入等离子体环境，从而识别和研究等离子体壁边界的反应。 这是通过用圆柱形基底代替反应器壁的小中空部分来实现的。 容纳这些诊断工具的室被密封到反应器壁的另一侧。 基板快速旋转；因此，其表面的一部分周期性地处于等离子体中，然后在很短的时间内面对诊断探针。连接到中空等离子体壁和诊断室上的大型真空泵去除从等离子体中泄漏的气体。 以这种方式，可以防止等离子体气体和带电物质扭曲诊断方法，并且可以分离和识别在等离子体壁上形成和产生的产物。等离子体暴露和分析之间的时间也可以通过改变基板旋转速度来改变，从而提取反应速率。拟议的工作将产生等离子体表面相互作用的基本知识，并将为改进对先进等离子体过程的控制提供关键信息，这些过程将用于制造未来的纳米器件。拟议的工作将提供丰富的科学和教育成果以及技术进步。这些研究将产生的基础知识，特别是分离此类复杂反应的新方法，对不同领域具有广泛的影响和潜在影响，包括等离子体聚变反应堆中的壁反应、催化、燃烧和大气化学，以及基础表面科学。计划开展多项外展活动，包括与等离子体科学联盟合作，以提高公众对半导体等离子体处理的社会效益的认识。