Studies on radical generation mechanism in the atmospheric plasma etching

在大气等离子体蚀刻中，由于平均自由程短，因此需要更强的电场来有效地产生辐射，但是，更强的电场导致等离子体的扩散和加工分辨率变差。虽然大气等离子体在加工速率和空间分辨率方面都做得很好，但很难在高水平上将它们联合收割机结合起来。在这项研究中，脉冲调制RF电源被建议用于实现高加工速率和精细的空间分辨率。为了将连续的射频功率调制为脉冲，在瞬间产生极强的电场。然后，预期在R.F.中有效地产生自由基。ON循环。预计这些自由基在R.F.中扩散之前会消失。OFF周期。我们给现有的RF电源一个脉冲调制的函数，并进行了几个实验，改变脉冲宽度和峰值RF功率。结果，我们发现这些参数和径向密度之间的关系，并了解反应气体的分解过程。特别是在使用SF6作为反应气体的情况下，发现实现了高加工速率和精细的空间分辨率。

In the atmospheric plasma etching, the stronger electric field is required for generating radiacals efficiently because of a short mean free path. But, the stronger electric field brings about spreading of a plasma and getting worse of machining resolution. Although the atmospheric plasma is doing very well as both a machining rate and a spatial resolution, it is difficult to combine them on the high level.In this study, a pulse modulated R.F.power is suggested to realize both a high machining rate and a fine spatial resolution. To modulate a continuous R.F.power to a pulse, an extremely strong electric field is generated in a moment. Then it is expected to generate radicals efficiently in a R.F.-ON cycle. And it is expected to these radicals are disappear before diffusing in a R.F.-OFF cycle.We gave the existence R.F.power supply a function of a pulse modulation, and made several experiments changing a pulse width and a peak R.F.power. As a result, we found relationship between these parameters and a density of radials, and understood a process of decomposition of reactive gases. Specially in the case of using SF6 as a reactive gas, it was found that both a high machining rate and a fine spatial resolution are realized.