Abstract
NLD (magnetic Neutral Loop Discharge) plasma has two major characteristic features that high density one is generated at the lower pressure than 1 Pa and is controllable by changing the magnetic coil current. Utilizing this feature, ionic etching should be carried out at the lower pressure than 1 Pa for chemical reactive substrates, for example, organic materials or ArF photo resists, because ionic etching is low selective and low reactive.
In Si etching process, the NLD plasma is utilized by employing sputter/etching method, which is scheduled cyclic. The NLD plasma is very stable for abrupt changing of the process pressure. This is brought on by weakly magnetized plasma. When PTFE (Poly Tetra-Fluoro-Ethylene) is used as a sputter target, deep etching of 180 μm is achieved for 7 μm pattern with aspect ratio of 25.7.
