Non-invasive plasma characterization through the ion velocity distribution function

イオンの速度分布関数による非侵襲的プラズマ特性解析

The high level of miniaturization and degree of integration of modern integral circuits based on semiconductor technology would be unthinkable without the use of various plasma-based processing steps during manufacturing, such as deposition and etching. These processes, their quality and efficiency depend critically on a number of plasma parameters, such as flux, density and energy of the ions. To optimize and control the semiconductor processing it is therefore desirable to be able to measure these quantities without affecting the plasma, its homogeneity and the quality of the ongoing surface treatment process. This is now possible with the method developed by us. It is an extension of the well-known mass spectrometry diagnostics. The method uses the distribution in velocities of the ions, measured at the wall of the process chamber by an energy resolved mass spectrometer, to obtain the plasma characteristics in the plasma volume. The parameters that can be determined include the velocity distribution of the ions in the plasma, their density, flux, mean energy and temperature.

半導体の微細化の進展，高集積化のためには，プラズマを使った成膜，エッチング技術が必要不可欠である。プラズマは，イオンフラックス，密度およびエネルギーなどのプラズマパラメータに特徴づけられ，半導体工程を最適化し，制御するためには，プラズマの均質性やウェハー表面の反応に影響を及ぼすことなく，プラズマパラメータを測定できることが望ましい。我々は一般的なエネルギー分解質量分析計を用いて，プラズマパラメータを測定する新しい方法を開発した。プロセスチャンバの側壁で測定するイオンの速度分布を用いて，プラズマ中のイオンの速度分布，密度，磁束，平均エネルギーおよび温度を決定する事が出来る。

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