Axially-resolved study of highly ionized magnetron sputtering

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:428009

Dickson, M; Qian, F; Hopwood, J ^[1]

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1. Northeastern Univ., Boston, MA (United States). Dept. of Electrical and Computer Engineering

Highly ionized fluxes of metal can be produced by sputtering atoms through a moderate pressure (1--100 mTorr), high density plasma. This method of deposition has important implications for the filling of high aspect ratio trenches and vias encountered in microelectronic fabrication. By ionizing the depositing species, one may electrostatically accelerate and collimate the depositing flux using conventional substrate biasing. Using a combination of collimation and resputtering, it is feasible to voidlessly fill 4:1 aspect ratios. A potential device for deposition of highly ionized metal consists of a dc magnetron which sputters atoms through a 13 cm-long region of high density argon plasma. The plasma is produced by an rf induction coil immersed in the deposition chamber. Minimizing the distance between the magnetron and wafer is critical to obtaining an economical deposition rate. As the throw distance is decreased, however, the fraction of metal ions at the wafer also decreases. Spatially-resolved optical measurements of Al{sup +} and Al emission show a nearly exponential rise in the relative ion fraction with distance from the sputter target. The experimental path length required for ionization will be related to the thermalization of the sputtered flux, measured electron temperature, and line-averaged electron density.

• OSTI ID: 428009
• Report Number(s): CONF-960634--
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
ALUMINIUM IONS
ELECTRON DENSITY
FABRICATION
MICROELECTRONIC CIRCUITS
PLASMA DENSITY
PLASMA PRODUCTION