The development of the equipment for the ultra precision aspherical optics using plasma CVM.

等离子体化学气相加工是一种利用常压下等离子体形成的自由基进行加工的方法。通过利用高压等离子体形成非常高密度的自由基，并且由于气体的小的平均自由程，可以将等离子体产生区域限制在高电场影响的电极附近。因此，可以联合收割机将与机械加工相同的加工效率和形状控制结合起来。本研究为实现基于纯化学原理的新型展成加工系统，进行了以下几个方面的工作：1）采用高精度高速旋转电极的数控等离子体CVM加工系统的设计与制造; 2）获得了对加工区域、加工速度和加工表面粗糙度有较大影响的各加工参数的基本数据，3）加工了同步辐射光束线用硅材料平面镜。虽然通过机械抛光得到的反射镜的平面度为158 nm（p-v），但是作为该系统的校正处理的结果，平面度为22.5nm（p-v）。4）对下一代半导体衬底SOI（Silicon On Insulator）晶片中的硅层进行薄膜减薄。利用该系统进行薄膜减薄，成功地将0.2μm厚的SOI层减薄到0.04μm。

Plasma CVM is a machining method using the radical formed by the plasma over the atmospheric pressure. The very high-density radical is formed by utilizing the high pressure plasma, and it is possible to limit the plasma generation region to the vicinity of the electrode which the high electric field affects, because of the small mean free path of the gas. Therefore, it is possible to combine processing efficiency and shape control which are equal to the mechanical machining. In this study, to make the new shape generating processing system based on the purely chemical principle, following items were practiced.1) Design and production of the numerical controlled plasma CVM machining system using the high-precise high-speed rotary electrode were carried out.2) Basic data on each machining parameter which give large effect in the localization of machining area, machining speed and machined surface roughness, were acquired.3) The plane mirror made of the silicon for synchrotron radiation beam line, was processed. Though the flatness of the mirror got by the mechanical polishing was 158nm (p-v), as a result of correction processing by this system, 22.5nm (p-v) was achieved.4) Film thinning of the silicon layer in SOI (Silicon On Insulator) wafer which was next generation semiconductor substrate was done. As a result of film thinning by this system, it succeeded in thinning the SOI layer of 0.2μm thickness to 0.04μm.