AVS 46th International Symposium
    Vacuum Metallurgy Division Tuesday Sessions
       Session VM+TF-TuM

Paper VM+TF-TuM9
Electrical and Pressure Probe Measurements of a Hollow Cathode Magnetron Plasma

Tuesday, October 26, 1999, 11:00 am, Room 620

Session: Ionized Plasma and Chemical Vapor Deposition
Presenter: K.F. Lai, Novellus Systems
Authors: K.F. Lai, Novellus Systems
Q. Lu, Novellus Systems
J. Chau, Novellus Systems
G.I. Font, Novellus Systems
Correspondent: Click to Email
The hollow cathode magnetron (HCM) is a new type of high-density plasma device developed for ionized physical vapor deposition (I-PVD). While I-PVD using RF inductively coupled plasma has a plasma density of 10@super 11@ to 10@super 12@ cm@super -3@ and operates best above tens of mTorr, the HCM achieves high levels of ionization at only a few mTorr, primarily due to its extremely high plasma density (~10 @super 13@ cm@super -3@). The plasma profiles of a HCM were measured using Langmuir probes and a novel pressure probe under various operating conditions for two different target materials (Cu and Ti). With the exception of the plasma edge where the presence of an energetic electron tail was clearly evident, the electron energy distribution function (EEDF) was approximately Maxwellian. The measured plasma density was found to increase linearly with the magnetron power whereas the electron temperature only has a weak dependence. Under similar operating conditions, the Ti HCM has a plasma density ~30% higher than that of Cu. A novel pressure probe was used to measure both the argon neutral and ion density profiles. Argon neutrals were measured when the probe was biased slightly above the plasma potential whereas both the argon neutrals and ions were collected when the probe was negatively biased. The percentage of gas rarefaction was found to increase with sputtering power but was only weakly dependent on argon density. The argon ion density profile (deduced by alternating the pressure probe bias) has similar shape as the electron density (measured by the Langmuir probe) indicating that argon is the dominant ion species. The experimental results are in good agreement with simulation using the hybrid plasma equipment model (HPEM) code.