Sputtering of Aluminum Film Using Microwave Plasma with High Magnetic Field

概要

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A newly developed microwave plasma with magnetic field (2B mode) two times higher than the [CR (electron cyclotron resonance) condition was, for the first time, applied to the sputtering of aluminum film at Ar pressure lower than 5×10^<-4> Torr. The highly (111)-oriented polycrystal grain structure with no other crystal orientation was obtained by cooling the substrate to -120℃. The degree of (111) orientation was further enhanced by applying negative bias on the substrate. On the other hand, the filling of a half-micron trench of aspect ratio 3 was satisfactorily achieved at 300℃, which was much lower than that by the conventional method employing DC (direct current) magnetron sputtering. The salient feature of 2B mode plasma is the high ionization rate of atoms, more than 50%. Hence, it is most likely that the enhancement of surface diffusion due to the ion bombardment effect on near surface atoms plays the essential role in the lowering of the filling temperature and the enhancement of (111) orientation.
社団法人応用物理学会の論文
1991-12-30