In situ plasma diagnostics study of a commercial high-power hollow cathode magnetron deposition tool

Liang Meng, Ramasamy Raju, Randolph Flauta, Hyungjoo Shin, David N. Ruzic, Douglas B. Hayden

Research output: Contribution to journalArticlepeer-review


Using a newly designed and built plasma diagnostic system, the plasma parameters were investigated on a commercial 200 mm high-power hollow cathode magnetron (HCM) physical vapor deposition tool using Ta target under argon plasma. A three dimensional (3D) scanning radio frequency (rf)-compensated Langmuir probe was constructed to measure the spatial distribution of the electron temperature (Te) and electron density (ne) in the substrate region of the HCM tool at various input powers (2-15 kW) and pressures (10-70 mTorr). The Te was in the range of 1-3 eV, scaling with decreasing power and decreasing pressure. Meanwhile, ne was in the range of 4× 1010 -1× 1012 cm-3 scaling with increasing power and decreasing pressure. As metal deposits on the probe during the probe measurements, a self-cleaning plasma cup was designed and installed in the chamber to clean the tungsten probe tip. However, its effectiveness in recovering the measured plasma parameters was hindered by the metal layer deposited on the insulating probe tube which was accounted for the variation in the plasma measurements. Using a quartz crystal microbalance combined with electrostatic filters, the ionization fraction of the metal flux was measured at various input power of 2-16 kW and pressure of 5-40 mTorr. The metal ionization fraction reduced significantly with the increasing input power and decreasing gas pressure which were attributed to the corresponding variation in the ionization cross section and the residence time of the sputtered atoms in the plasma, respectively. Both the metal neutral and ion flux increased at higher power and lower pressure. The 3D measurements further showed that the ionization fraction decreased when moving up from the substrate to the cathode.

Original languageEnglish (US)
Pages (from-to)112-118
Number of pages7
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Issue number1
StatePublished - 2010

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films


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