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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]

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]

A compact and transportable two laser beam infrared (TOBI) system based on infrared absorption spectroscopy has been developed for time-resolved plasma diagnostics. The TOBI system contains two independent tunable diode lasers which can be directed through a plasma or into a multipass cell for exhaust gas detection. Rapid scan software with real-time line shape fitting provides a time resolution up to 10 μs to study chemical kinetic processes of infrared active compounds in plasmas. The capabilities of the TOBI system have been demonstrated in plasmas of pulsed H[sub 2]–N[sub 2] surface wave and in pulsed air–CH[sub 4] dc discharges. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Over the past few years mid-infrared absorption spectroscopy based on quantum cascade lasers operating over the region from 3 to 12 µm and called quantum cascade laser absorption spectroscopy or QCLAS has progressed considerably as a powerful diagnostic technique for in situ studies of the fundamental physics and chemistry of molecular plasmas. The increasing interest in processing plasmas containing hydrocarbons, fluorocarbons, nitrogen oxides and organo-silicon compounds has led to further applications of QCLAS because most of these compounds and their decomposition products are infrared active. QCLAS provides a means of determining the absolute concentrations of the ground states of stable and transient molecular species at time resolutions below a microsecond, which is of particular importance for the investigation of reaction kinetics and dynamics. Information about gas temperature and population densities can also be derived from QCLAS measurements. Since plasmas with molecular feed gases are used in many applications such as thin film deposition, semiconductor processing, surface activation and cleaning, and materials and waste treatment, this has stimulated the adaptation of QCLAS techniques to industrial requirements including the development of new diagnostic equipment. The recent availability of external cavity (EC) QCLs offers a further new option for multi-component detection. The aim of this paper is fourfold: (i) to briefly review spectroscopic issues arising from applying pulsed QCLs, (ii) to report on recent achievements in our understanding of molecular phenomena in plasmas and at surfaces, (iii) to describe the current status of industrial process monitoring in the mid-infrared and (iv) to discuss the potential of advanced instrumentation based on EC-QCLs for plasma diagnostics. [ABSTRACT FROM AUTHOR]

Relative transition probabilities of spontaneous emission in the R and P branches of the A1Π→X1Σ+ (0–0) band of BH molecule have been obtained for the first time. It was observed that measured ratios of the line strengths are in agreement with corresponding ratios of Ho¨nl–London factors. Thus, the non-adiabatic effect of perturbations is negligibly small and Ho¨nl–London formulas may be used for derivation of rovibronic population densities from measured line intensities of the (0–0)R branch of BH. The (0–0)P branch is less prospective because too much overlapping by other BH emissions cannot be avoided with the moderate resolution spectrometers usually used in plasma spectroscopy. General considerations are illustrated on the example of a low-pressure plasma of a planar microwave discharge in a H2–Ar–B2H6 (64:33:3) gas mixture (total pressure 1–2.5 mbar, power 1.2–2.4 kW). The values of the rotational temperatures obtained directly for the excited electronic-vibrational states d3Πu−, v′=2 (Td2rot(H2)) and A1Π+, v′=0 (TA0rot(BH)) and those calculated in the framework of excitation-deactivation models for the ground X1Σu+, v=0 vibronic states (TX0rot(H2) and TX0rot(BH)) have been analysed. It has been observed that TX0rot(H2) and TX0rot(BH) are in excellent agreement, while compared to these values TA0rot(BH) is noticeably higher and Td2rot(H2) is about two times lower. Thus, the simultaneous measurements of intensity distributions in the rotational structure of BH and H2 emission bands can be used as a prospective method for determination of gas temperature in non-equilibrium boron and hydrogen containing plasmas. [Copyright &y& Elsevier]