REG: Engineering Research Equipment: A Mass Spectrometer with Ion Monitoring Capability for Measuring Ions and Molecular Species in Plasma Discharges

REG：工程研究设备：具有离子监测功能的质谱仪，用于测量等离子体放电中的离子和分子种类

• 批准号: 9310654
• 负责人: Brian Thompson
• 金额: $ 6.5万
• 依托单位: University of Kansas Center for Research Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-07-15 至 1994-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9310654&HistoricalAwards=false
• 关键词: REG; Engineering; Research; Equipment; Mass

Radio-frequency plasma discharges are used in the semiconductor industry for plasma deposition and plasma etching. In a typical reactor, a radio-frequency (RF) voltage is applied between two parallel electrodes inside a vacuum chamber at 0.01 to 10 Torr. The electric fields created accelerate electrons to very high energy levels. These electrons collide with molecules to produce more electrons, ions, and highly reactive neutral radical species. These chemical species then react with each other and solid surfaces according to the particular application. Because the resultant composition of the gas phase will affect the rates and qualities of the etching or deposition, it is useful to sample the gas composition through a small orifice to a mass analyzer. Besides the role of neutral reactive species, the bombardment of the solid (wafer) surface by ions is also important. Because of the electrical interaction of electrons and ions in the plasma, a plasma "sheath" is formed near any solid surface. This sheath contains an electric field that repels electrons and keeps them better contained within the center of the plasma. The same electric field will accelerate positive ions towards the solid surface. Therefore, the ions are directed to the surface with substantial energy (mean energies of a few eV to several hundred eV). This directed, high- energy ion bombardment at solid surfaces produces directional etching in plasma etching applications, and it can alter film properties in plasma assisted chemical vapor deposition (CVD) of thin films. Because of this important role of ions, the PI plans to sample this ion bombardment with subsequent analysis of the ion energy distribution and the composition of this ion stream. Mass spectrometry is a technique to determine the composition of either of these sampled neutral species or ions. In the case of sampling uncharged molecules, these molecules first pass through an ionizing chamber where they are bombarded by electrons with sufficient energy to ionize a substantial fraction of the molecules. For sampling the ions directly from the plasma, this step is not needed. Once the ions are created or sampled, they pass through a mass filter (quadrupole) that allows ions with a narrow range of atomic mass to electrical charge ration (m/q) to pass through. The flux of ions that pass through the filter at this m/q are then collected and measured with a Faraday cage or electron multiplier. Thus by tuning through a range of m/q, the distribution of ions with particular m/q is measured. This is a Research Equipment Grant (REG) to purchase a quadrupole mass spectrometer with ion monitoring capabilities which will be used to examine the neutral molecular species and ionic species from plasma discharges and a chemical vapor deposition reactor.

射频等离子体放电用于 用于等离子体沉积和等离子体的半导体工业 蚀刻 在典型的反应器中，射频（RF）电压 施加在真空中的两个平行电极之间 在0.01至10托的腔室中。 产生的电场 将电子加速到非常高的能级。 这些 电子与分子碰撞产生更多的电子， 离子和高活性中性自由基物种。 这些 然后化学物质相互反应， 根据特定的应用。 因为 气相的合成物将影响反应速率 以及蚀刻或沉积的质量， 通过小孔对气体成分进行取样， 分析仪 除了中性活性物质的作用外， 离子对固体（晶片）表面的影响也很重要。 由于电子和离子的电相互作用， 在等离子体中，在任何固体附近都会形成等离子体“鞘”， 面 这个鞘层包含一个电场， 电子，并使它们更好地包含在中心， 血浆 同样的电场会加速为正 离子向固体表面移动。 因此，离子是 以相当大的能量（平均能量 几eV到几百eV）。 这是一个高，高- 高能离子轰击固体表面产生定向的 蚀刻在等离子体蚀刻应用中，并且它可以改变膜 等离子体辅助化学气相沉积（CVD）性能 的薄膜。 由于离子的这种重要作用，PI 计划对这种离子轰击进行取样， 离子的能量分布和组成 源源不断的 质谱分析法是一种测定 这些中性物质或离子的样本。 在 取样不带电分子的情况下，这些分子首先 穿过电离室，在那里它们被 电子有足够的能量来吸收大量的 分子的一部分。 为了直接对离子进行采样 从等离子体中分离，则不需要该步骤。 一旦离子 产生或采样后，它们通过质量过滤器 （四极），允许离子与一个狭窄的范围内的原子 质量电荷比（m/q）通过。 的 然后，以该m/q通过过滤器的离子通量为 用法拉第笼或电子收集和测量 增效器. 因此，通过在m/q的范围内调谐， 测量具有特定m/q的离子的分布。 这是一项研究设备补助金（REG），用于购买 具有离子监测能力的四极质谱仪 它将被用来检查中性分子种类 以及来自等离子体放电和化学蒸气的离子物质 沉积反应器