GAP-FILLING OF CU EMPLOYING SUSTAINED SELF-SPUTTERING WITH INDUCTIVELY-COUPLED PLASMA IONIZATION

Copper filling of high aspect-ratio gaps has been investigated systema tically using sustained self-sputtering with ICP ionization. In order to understand gap-filling characteristics, deposition and/or resputter ing rates have been measured as a function of the substrate bias, indu ctively coupled plasma (ICP) power, and the incident angle of ions to the substrate. Since Ar ions are excluded from the plasma, considerabl e improvement of the bottom coverage has been achieved with proper sub strate biasing. This paper also illustrates both the limiting problems and the possibility of the high aspect-ratio hole filling by this met hod.