Development of Low-Energy Particle-Beam Sources for Super-fine Plasma Processing

为了实现超精细等离子体加工，必须满足以下几个要求：入射到基板上的离子必须具有单色平行速度和不产生损伤的低能量，并且必须具有高通量、均匀和大的光束。通过开发低压、大面积、高密度、低等离子体电位的等离子体来满足这些要求。为此，我们开发了一种在表面磁场下电感耦合射频放电的新型等离子体生产方法。多偶极表面磁场产生以下效应：良好的约束高能电子，增强等离子体产生，减少体电子扩散损失，并由此增加等离子体密度和均匀性。等离子体电位的下降也是意料之中的。在我们的表面磁约束原型装置中获得了如下令人满意的结果：放电等离子体在tor2等低压下持续放电。获得了均匀、大直径（-40cm）、低等离子体电位（- 20v）的高密度等离子体。等离子体电位可通过外部偏置小电极控制。另一方面，我们研究了离子在表面诱导自由基的产生；高能多原子离子撞击表面时的碎裂。这种类型的等离子体-表面相互作用是令人感兴趣的，因为它可以应用于一种新的自由基束源。

In order to realize super-fine plasma processings, several requirements should be satisfied : Ions incident on a substrate should have a monochromatic parallel velocity and a low energy not to give rise to damage, and also a high-flux, uniform, and large beam is necessary. These requirements will be met by developing a low-pressure, large-area, high-density plasma with the low plasma potential. To do this, we have developed a novel plasma production by an inductively coupled rf discharge under a surface magnetic field.Multi-dipole surface magnetic fields produce following effects ; good confinement of high energy electrons, enhancement of plasma production, reduction of bulk-electron diffusion loss, and the resultant increase in plasma density as well as the uniformity. The decrease in the plasma potential is also expected.Promising results were obtained in our prototype device with surface magnetic confinement as follows :1. The discharge plasma was sustained at low pressures such as Torr.2. A uniform, large-diameter (-40cm), high-density plasma with low plasma potential (-20 V) was obtained.3. The plasma potential was controllable with an externally biased small electrode.On the other hand, we have studied ion-induced radical production on surfaces ; fragmentation of high-energy poly-atomic ions at their impact on surfaces. This type of plasma-surface interactions is of interest since it can be applied to a new source of radical beams.