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Inductively coupled plasma reactive ion etching of Pd thin films with TiN hard masks was carried out in a CH 3 COOH/Ar gas mixture. The addition of CH 3 COOH to Ar gas decreased the etch rate but a good etch profile with a high degree of anisotropy was obtained at 50% CH 3 COOH/Ar. Variations in the etch parameters showed that high inductively coupled plasma power and dc-bias voltage improved the etch profile. X-ray photoelectron spectroscopy and optical emission spectroscopy results revealed that the Pd films in CH 3 COOH/Ar gas followed the sputtering etch mechanism assisted by the oxidation and sidewall protection provided by polymer films.

The etch characteristics of TiN hard mask-patterned CoFeB thin films were investigated by inductively coupled plasma reactive ion etching in an C2H5OH/Ar gas mixture. The effects of gas mixture concentration, rf coil power, dc bias voltage, and process pressure on the etch profile were investigated. Etch profiles with a high degree of anisotropy were achieved with C2H5OH concentrations from 25% to 50%. Further increases in the C2H5OH concentration decreased the degree of anisotropy of the etch profile. The etch profile improved as the rf coil power and dc bias increased and the process pressure decreased. Optical emission spectroscopy revealed the presence of [C], [H], [O], and [Ar] species, among others, in the plasma, while X-ray photoelectron spectroscopy analysis of the CoFeB thin film surface revealed the presence of Co, Fe, and B oxides, and the deposition of carbon-containing compounds. Results suggest that the etch mechanism is driven by physical sputtering, assisted by oxidation of the films and formation of a CxHy inhibition layer.

High density plasma etching of Pd thin films masked with TiN films was performed using CH3OH/Ar, C2H5OH/Ar, CH4/Ar, and CH4/O2/Ar gas mixtures. The etch rates of the Pd films and TiN masks in all the gas mixtures decreased whereas the etch selectivities increased. The etch profiles of the Pd films etched under C2H5OH/Ar gas were better than those obtained with CH3OH/Ar gas. Addition of O2 gas to the CH4/Ar gas mixture considerably improved the etch profiles of the Pd films. CH4, Ar, and O2 were found to play a critical role in obtaining a vertical etch profile with smooth sidewalls. Energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy revealed the formation of polymeric layers and PdOx compounds on the sidewalls and the film surface. Good etch profiles with a high degree of anisotropy were achieved with the use of C2H5OH/Ar and CH4/O2/Ar gas mixtures.

Inductively coupled plasma reactive ion etching of Ta thin films masked with photoresist was performed using C2F6/Ar, HBr/Ar and Cl2/Ar gases. The etch characteristics such as etch rate, etch selectivity and etch profile were investigated in different gas concentrations of each gas. The Cl2 chemistry showed high degree of anisotropy in etch profile as well as fastest etch rate and highest etch selectivity of Ta films among these gases. Optical emission spectroscopy revealed that the increase in chlorine radicals with increasing Cl2 concentration was responsible for the increase in the Ta etch rate. The etch rate of Ta films increased with increasing ICP rf power and dc-bias voltage, and decreasing process pressure. Good etch profiles were obtained at high rf power and dc-bias voltage, and low process pressure. X-ray photoelectron spectroscopy confirmed the existence of a chemical reaction of Ta with chlorine radicals by forming tantalum chlorides. These results suggested that Ta etching in Cl2/Ar follows the typical reactive ion etching mechanism. It was concluded that a high degree of anisotropy and high etch rate of Ta films were achieved using Cl2/Ar gas.

The etch characteristics of Ru thin films patterned with TiN hard masks in O 2 /Ar, CH 4 /Ar and O 2 /CH 4 /Ar gas mixtures were studied using inductively coupled plasma reactive ion etching. When the Ru films were etched in O 2 /Ar gas, the etch rates of the Ru films and TiN hard masks decreased but the etch selectivity of the Ru films to the hard mask increased with increasing O 2 concentration. The etch profiles of Ru films at various O 2 concentrations were very similar, showing high etch slopes of > 80° with uneven sidewalls. In the case of CH 4 /Ar gas, as the CH 4 concentration increased, the etch rates of the Ru films and TiN hard masks and the etch selectivity of Ru films decreased. The etch profile of Ru films etched in 20% CH 4 /Ar showed the etch slope of approximately 60° and the etch slopes became worse with increasing CH 4 concentration. The addition of O 2 to the CH 4 /Ar gas resulted in a significant improvement in the etch profile, but both etch rates decreased slightly. Optical emission spectroscopy of O 2 /CH 4 /Ar plasma showed that O species could oxidize the Ru films to RuO x , and that inhibition layers containing C or CH x were formed, which protected the pattern sidewalls. X-ray photoelectron spectroscopy also identified the formation of RuO x and C or CH x compounds on the film surface. These findings indicated that Ru etching in O 2 /CH 4 /Ar gas chemistry could provide a good etch profile without redeposition or etch residues.

The etch characteristics of TiN hard mask patterned CoFeB thin films were investigated using an inductively coupled plasma reactive ion etching in a CH3COOH/Ar gas mixture. The etch characteristics of CoFeB magnetic thin film and TiN hard masks were investigated as a function of gas mixture concentration, coil rf power, dc-bias voltage and gas pressure. As CH3COOH concentration in the CH3COOH/Ar gas mixture increased, the etch rates of CoFeB films and degree of anisotropy in the etch profile decreased, while increased coil rf-power and dc bias voltage and reduced gas pressure increased the etch rate and improved the etch profile. Additionally, a thick hydrocarbon layer was formed on the film surface at a dc-bias voltage of 100 V. X-ray photoelectron spectroscopy and optical emission spectroscopy analyses of the etched films at various CH3COOH concentrations suggest that CoFeB thin films etched in a CH3COOH/Ar gas mixture follow a physical sputtering etch mechanism assisted by oxidation of the film and formation of a protective inhibition layer on the film surface. Etching of TiN patterned CoFeB films with a high degree of anisotropy was accomplished without redepositions or etch residues when conducted under high sputtering conditions.

Changes in the inductively coupled plasma reactive ion etching characteristics of TiO 2 thin films in response to the addition of HBr, Cl 2 and C 2 F 6 to Ar gas were investigated. As the HBr, Cl 2 and C 2 F 6 concentration increased, the etch rate increased; however, the etch profile degree of anisotropy followed a different trend. As HBr concentration increased, the greatest anisotropic etch profile was obtained at 100% HBr, while the greatest anisotropic etch profile was obtained at concentrations of 25% when etching was conducted under C 2 F 6 and Cl 2 . Field emission scanning electron microscopy revealed that 25% C 2 F 6 generated the greatest vertical etch profile; hence, etch parameters were varied at this concentration. The effects of rf power, dc-bias voltage and gas pressure on the etch rate and etch profile were also investigated. The etch rate and degree of anisotropy in the etch profile increased with increasing rf power and dc-bias voltage and decreasing gas pressure. X-ray photoelectron spectroscopy analysis of the films etched under a C 2 F 6 /Ar gas mixture revealed the existence of etch byproducts containing F (i.e. TiF x ) over the film. C x F y compounds were not detected on the film surface, probably due to contamination with atmospheric carbon.

Inductively coupled plasma reactive ion etching (ICPRIE) of Ru thin films patterned with TiN hard masks was investigated using a CH3OH/Ar gas mixture. As the CH3OH concentration in CH3OH/Ar increased, the etch rates of Ru thin films and TiN hard masks decreased. However, the etch selectivity of Ru films on TiN hard masks increased and the etch slope of Ru film improved at 25% CH3OH/Ar. With increasing ICP radiofrequency power and direct current bias voltage and decreasing process pressure, the etch rates of Ru films increased, and the etch profiles were enhanced without redeposition on the sidewall. Optical emission spectroscopy and X-ray photoelectron spectroscopy were employed to analyze the plasma and surface chemistry. Based on these results, Ru thin films were oxidized to RuO2 and RuO3 compounds that were removed by sputtering of ions and the etching of Ru thin films followed a physical sputtering with the assistance of chemical reaction.

The inductively coupled plasma etching characteristics of Co2MnSi thin films patterned using a TiN hard mask were investigated by the addition of CH3OH to Ar gas. As the CH3OH concentration increased, the etch rates of Co2MnSi magnetic thin films and TiN hard mask decreased, but the etch profile improved. The effects of rf power, dc-bias voltage and gas pressure on the etch rate and etch profile were also investigated. The etch rate and etch profile degree of anisotropy increased with increasing rf power and dc-bias voltage and decreasing gas pressure. Optical emission spectroscopy analysis revealed that [H], [O], [CO], [OH], [CH3O] and [Ar] species in the CH3OH/Ar plasma played a key role in achieving a good etch profile.

High density plasma etching of MgO thin films patterned with Ti (or TiN) hard masks was conducted using Cl2/Ar, CH3OH/Ar and CH4/Ar gases. As the concentration of each gas increased, the etch rate of MgO thin films decreased and there was no enhancement of etch profiles except for those obtained using CH4/Ar gas. The etch profiles of MgO thin films under CH4/Ar gas, which is non-corrosive and non-toxic, were improved without redeposition with increasing CH4 concentration. The enhancement of etch profiles in CH4/Ar gas was attributed to both the formation of a protective layer containing hydrogen and hydroxyl species on the sidewall of the patterns and the formation of magnesium compounds during the etching. Optical emission spectroscopy and X-ray photoelectron spectroscopy analyses showed that magnesium hydroxide was formed due to chemical reactions on the film surface under CH4/Ar gas. Additionally, the MgO thin films were found to be etched by a physical sputtering etching mechanism that was influenced by a chemical reaction.

Zn(O,S) thin films were successfully deposited by reactive sputtering using Ar and O2 gas mixtures at 473 K. X-ray diffraction patterns revealed that the well crystallized Zn(O,S) films were deposited with increasing oxygen concentration in O2/Ar, resulting in a shift of the Zn peak of 28.5° to a higher angle, closer to the ZnO peak of 34.4°. Zn(O,S) films were composed of grains agglomerated from small particles, which grew gradually with increasing oxygen concentration. The depth profiles and energy dispersive spectroscopy results of the films indicated that the O/(O+S) ratio increased from 0.04 to 0.81, and all Zn(O,S) films were Zn rich with uniform concentrations of each component. X-ray photoelectron spectroscopy revealed that, as the oxygen concentration increased to 2%, the ZnS films were transformed to Zn(O,S) films via substitution of oxygen for sulfur.

Co2MnSi thin films masked with TiN films were etched in CH4/Ar and CH4/O2/Ar plasmas by inductively coupled plasma reactive ion etching. The etch rates decreased with increasing CH4 concentration in CH4/Ar gas, whereas the etch selectivity increased. The addition of O2 to CH4/Ar gas resulted in significant improvement in the etch profile but a decrease in the etch rates. Optical emission spectroscopy showed that a variety of COx, OH, and H2O species were formed in the CH4/O2/Ar plasma, acting a role as a passivation layer to protect the pattern sidewalls. X-ray photoelectron spectroscopy also confirmed the formation of metal oxides on the film surface, which could be sputtered off easily by Ar ion bombardment. A high degree of anisotropy of Co2MnSi films was obtained in the CH4/O2/Ar etch gas.