Design of the atmospheric pressure low temperature plasma polishing system for the machining of ultra-smooth surfaces

A novel precision machining method for ultra-smooth surfaces and the corresponding facilities were presented. This method utilizes the atmospheric pressure low temperature plasma to excite reactive gases in order to generate high density reactive radicals. Then the radicals cause chemical reactions with the workpiece surface atoms producing volatile products, which performs the atom scale removal process. As the machining process is chemical in nature, this method avoids surface/subsurface defects. A self-fabricated system was built to implement this atmospheric pressure plasma polishing (APPP) method. And a capacitance coupling radio-frequency plasma torch was firstly introduced into the atmospheric pressure plasma polishing system. The analysis of atomic emission spectroscopy has demonstrated the validity of the system. Furthermore, the operations applied on silicon wafers also indicate that a removal rate of 1.46 mm ³/min and surface roughness of 0.6 nm (R _a) have been achieved.