Using a newly designed and built plasma diagnostic system, the plasma parameters were investigated on a commercial 200 mm high-power hollow cathode magnetron ͑HCM͒ physical vapor deposition tool using Ta target under argon plasma. A three dimensional ͑3D͒ scanning radio frequency ͑rf͒-compensated Langmuir probe was constructed to measure the spatial distribution of the electron temperature ͑T e ͒ and electron density ͑n e ͒ in the substrate region of the HCM tool at various input powers ͑2-15 kW͒ and pressures ͑10-70 mTorr͒. The T e was in the range of 1-3 eV, scaling with decreasing power and decreasing pressure. Meanwhile, n e was in the range of 4 ϫ 10 10-1ϫ 10 12 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.

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As semiconductor feature sizes continue to decrease, the phenomena of line-edge roughness (LER) becomes more disruptive in chip manufacturing. While many efforts are underway to decrease LER from the photoresist, post-developed smoothing techniques may be required to continue shrinking chip features economically. This paper reports on one such method employing the use of a broad ion beam at grazing incidence along the features. This method smooths relatively long spatial-length LER, a potential advantage over other smoothing techniques that focus on just molecular-scale LER. LER reduction numbers using Ne and Ar beams are reported at both short and long spatial wavelengths. Variables include beam energy, length of time and angular dependence. LER measurements are taken using the Hitachi image-analysis software on top-down analytical scanning electron microscope (SEM) measurements. Line-profile data are taken from cross-sectional SEM photographs. Tests have achieved a reduction in LER from 9.8 ± 0.67 nm to 5.5 ± 0.86 nm for 45 nm critical dimensions using an Ar beam at 500 eV for 6 s at an 85 • angle of incidence. A reduction from 10.1 ± 1.07 nm to 6 ± 1.02 nm was shown using an Ar beam at 1000 eV for 4 s at a 60 • angle of incidence.

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An RF-assisted closed-field dual magnetron sputtering system was developed to characterize the plasma and the ionization fraction of sputtered material to provide a suitable system for depositing optical thin films on large-area substrates at low temperatures (<130 • C). The 'prototype' system consists of dual 76 mm dc magnetrons operated at both balanced and unbalanced (closed-field) configurations with an RF coil to initiate a secondary plasma. The RF plasma assistance enhanced the electron density to one order of magnitude higher, increased the deposition rate and effectively enhanced the ionization fraction of the sputtered flux to above 80% as measured from the quartz crystal microbalance combined with electrostatic filters. Based on the prototype system, a large-scale RF-assisted system using two 9 × 46 cm linear magnetron cathodes was also developed and evaluated. Both systems were also tested for reactive deposition of indium tin oxide on both small-scale and large-area polyethylene terephthalate substrates with the actual substrate surface temperature monitored to be <130 • C. From both the evaluation results of the plasma characterization and deposition performance, the prototype and the large linear magnetron system were found to be suitable for reactive thin film deposition of compound targets that can be extended to various types of optical coatings.