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Plasma patterning processes play a key role in modern Ultra Large Scale Integration (ULSI) device fabrication. With further scaling of device dimensions, plasma process characteristics become more and more the limiting factor in pattern minimization, not least due to parasitic effects caused by different plasma properties. Such effects are geometrical deviations in the etch profiles, the loss of critical dimensions, the undercut as well as the most critical sidewall damage while etching trenches and vias to fabricate the circuit contact and metallization system. Especially for modern dielectric materials on the base of carbon‐doped silica these drawbacks are much pronounced and worsen performance and power consumption of microelectronic devices. Finally, the charge damage of thin gate oxides during plasma processing results in reduced reliability and functionality of microelectronic devices. The complex interactions between conditions in the plasma bulk and the impacts on the wafer surface are not yet understood completely. With respect to the increasing complexity of modern semiconductor plasma etch equipment, the optimization of patterning processes using the empirical method becomes more and more impossible. This paper overviews typical challenges during plasma patterning processes in 28 nm and 22 nm technology nodes by means of today's Back‐End of Line integration schemes. Different plasma diagnostic methods provide an insight into the physical and chemical conditions of different etch chambers and their influence on process results and damaging behaviour. [ABSTRACT FROM AUTHOR]

A microwave torch in nitrogen has been designed for the evaporation of aluminium (Al) wires potentially to be used for the synthesis of aluminium nitride (AlN). The torch, created on the tip of a metallic nozzle, is compatible with vacuum conditions and can be operated in continuous mode up to atmospheric pressure. Al wires to be evaporated are fed through the axis of the nozzle. Time‐resolved photography is applied to analyse the time evolution and stability of the interaction of the Al wire with the discharge. Optical emission spectroscopy is used (a) for the determination of the gas temperature of the active discharge, which is found to be in the range 1500–3500 K depending on the experimental conditions, and (b) for the estimation of the densities of Al and N atoms in the afterglow region, which are in the range 1011–1012 and of 1013–1014 cm−3, respectively. It is found that the part of the Al wire that is directly exposed to the nitrogen torch absorbs a considerable amount of the microwave energy, supporting its evaporation. In addition, the dissociation of molecular nitrogen has to be considered as an important process of power dissipation. Further technical development of the torch is necessary for the envisaged synthesis of AlN. [ABSTRACT FROM AUTHOR]

Plasmas in interaction with surfaces are of key importance in a wide range of applications, which include materials technology, microelectronics, environmental issues, and biomedicine. The intense use of plasma technological processes demands proper plasma diagnostic techniques for monitoring, controlling and optimization purposes in industrial environments. In particular, for the improvement of the efficiency of a production process, in situ diagnostic techniques with online capabilities are favorable. From the middle of the last decade a variety of phenomena in molecular non-equilibrium plasmas in which many short-lived and stable species are produced have been successfully studied with quantum cascade laser absorption spectroscopy (QCLAS) in the mid-infrared spectral range. It has been possible to determine absolute concentrations of species, temperatures, degrees of dissociation, dynamics of reaction processes and phenomena involving plasma-surface interactions using spectroscopy, thereby providing a link with chemical and kinetic modelling of the plasma. Since quantum cascade lasers (QCLs) emit near room temperature, i.e., without the need of cryogenic cooling, very compact and robust spectroscopic instruments can be designed. This has stimulated the adaptation of infrared spectroscopic techniques to industrial requirements. Recent applications of infrared absorption spectroscopy using QCLs for in situ monitoring of plasma processes in industrial environments are reviewed. Examples which emphasize the capabilities of QCLAS as plasma diagnostic technique in industrial plasma processes will be given. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Fuel and synthesis gases generated by thermochemical gasification of renewable biomass resources and organic waste fractions are considered to be promising for recent and future energy demands. However, the presence of tar species in the gas mixture is an economic obstacle in the commercialization of this technology. The influence of non-thermal plasma on gas phase naphthalene [ABSTRACT FROM AUTHOR]

Low-pressure pulsed DC N2-H2 plasmas with admixtures of CH4 were investigated in a comparative study in two different types of reactors, (i) a cylindrical industrial scale active screen plasma nitriding (ASPN) reactor and (ii) a laboratory scale plasma nitriding monitoring reactor (PLANIMOR) with a linear electrode configuration. Applying infrared laser absorption spectroscopy (IRLAS) the evolution of the molecular concentrations of four stable molecules, CH4, HCN, NH3, and C2H2 has been monitored. The degree of dissociation of the carbon containing precursor, CH4, varied between 80 and 95%. The concentrations of the molecular reaction products have been found in a range of 1011 to 1016 molecules cm-3. By analyzing the development of the molecular concentrations at changes of the screen plasma power, the gas mixture and the admixture of CH4, a similar behavior of the monitored species depending on the varied parameters has been found in both reactors with NH3 and HCN as the main products of plasma conversion. The fragmentation efficiency of methane has been determined, decreasing from 2.4 to 0.8 × 1015 molecules J-1 with the increasing power of the screen plasmas in both reactors. With the help of optical emission spectroscopy (OES) the rotational temperature of the N+2 ions in the plasma could be determined, being in a range of 650...920 K where the rotational temperature of the screen plasma in the ASPN reactor is approximately 100 K higher than that in PLANIMOR. Also with power the ionic component of nitrogen molecules, i.e. the intensity of the N+2 -(0-0) band of the first negative system, which has been used as the reference parameter for comparing both reactors, increases strongly in relation to the intensity of the neutral component, represented by the N2-(0-0) band of the second positive system. In addition, steel samples have been treated in both the ASPN reactor and PLANIMOR leading to comparable nitriding results. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

In Ar and Ar/N2 radio frequency (RF) discharges with admixtures of aluminium tri-isopropoxide (ATI) the fragmentation of this metal-organic precursor was studied by means of Fourier Transform Infrared (FTIR) spectroscopy using an optical long path cell providing an optical length of l = 17.2 m. The experiments were performed in an asymmetric capacitively coupled process plasma at a frequency of f = 13.56 MHz and at pres-sure values in the range of p = 1-10.5 Pa. The discharge power was chosen between P = 10-100 W. Using FTIR spectroscopy the evolution of the concentrations of ATI and of six stable molecules, CH4, C2H2, C2H4, C2H6, CO and HCN, was monitored under flowing conditions at gas flows of Φ total = 0.5-14.5 sccm in the discharge. The concentrations of the reaction products were measured tobe between 2 x 1012 molecules cm-3 as e.g. found for C2H4and C2H6, and 5 x 1013 molecules cm-3, as e.g. in the case of CO. In the plasma a complete dissociation of the precursor ATI was found at a power value of about P = 80 W independent on the admixture of Ar or N2. The fragmentation efficiency (F E) of the reaction products which originate from the ATI molecules ranges between 0.2 and 4 x 1016 molecules J-1 while the fragmentation rate (F R) reached up to 2.5 x 1018 molecules s-1. The multi component detection ability of the spectrometer served to analyse the carbon balance of the by-product formation. For all experiments, the carbon balance never exceeded 25%. Therefore, in the plasmas the majority of the provided carbon is most likely deposited at the reactor walls or forms dust particles or higher molecular C xH y. The conversion efficiencies (C E) of the produced molecular species ranges between 0.1 x 1015 molecules J-1 for C2H4 and 5 x 1015 molecules J-1 for C2H6 depending on the discharge conditions of the RF plasma. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

In Ar and Ar/N2 RF plasmas with admixtures of aluminum tri-isopropoxide (ATI) the fragmentation of this metal-organic precursor has been studied by means of infrared absorption spectroscopy (IR-AS) using an external-cavity quantum cascade laser (EC-QCL) arrangement. The experiments were performed in an asymmetric capacitively coupled reactor at a frequency of f = 13.56 MHz and a pressure of up to p = 10 Pa. The discharge power was in the range of P = 40 - 100 W. Using EC-QCLAS the evolution of the concentrations of six stable molecules, CH4, C2H2, C2H4, H2O, HCN and HNO3, has been monitored in the plasma. The concentrations of these plasma chemical products were found to be in the range of about 7 × 1012 - 2 × 1014 molecules cm-3 (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]