Sputter heating in ionized metal physical vapor deposition

Conference · Thu Jul 01 04:00:00 EDT 1999

OSTI ID:20034255

Lu, J; Kushner, M J

Ionized metal physical vapor deposition (IMPVD) is a process whereby metal fluxes with a high ionization fraction can be deposited for microelectronics fabrication. IMPVD reactors augment a magnetron sputter source, which produces the metal vapor, with an auxiliary plasma source, typically an inductively coupled plasma, to ionize the metal atoms during their transit from the target to the substrate. Recent experimental observations suggest that gas heating resulting from the slowing of sputtered atoms from the target produces sufficient rarefaction that deposition properties, such as the ionization fraction of the metal atom flux, may be affected. In this paper, sputter heating and subsequent rarefaction in IMPVD reactors is investigated using a plasma equipment model. The Hybrid Plasma Equipment Model has been improved to include processes relevant to sputter heating. Specifically, the algorithms for yields and sputtered atom energies have been improved to account for the ion identity and energy as a function of position on the target. The transport and slowing of sputtered atoms is addressed using a Monte Carlo simulation. By collecting statistics on the energy and momenta of slowing sputtered atoms before and after a collision, rates of momentum transfer and random heating of the gas are computed. These quantities are then used in the momenta and energy equations for neutral and ion species. Parametric studies have been performed for sputter heating in aluminum and copper IMPVD systems operating at low to high powers ({le} 1,200 W ICP, {le} 2,500 W magnetron) in 10s mTorr Ar. When operating with ICP excitation only, gas temperatures of 800 K are typically obtained with powers of > 1 kW. Additional temperature rises of 500--1,500 K from sputter heating can be obtained, depending on the magnetron power and accommodation coefficient of the gas on the walls.

• Research Organization: Univ. of Illinois, Urbana, IL (US)
• OSTI ID: 20034255
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
42 ENGINEERING
CHEMICAL REACTORS
IONIZATION
MICROELECTRONIC CIRCUITS
PARAMETRIC ANALYSIS
PHYSICAL VAPOR DEPOSITION
PLASMA PRODUCTION
PLASMA SIMULATION
SPUTTERING