A sustainable electroless copper coating process was developed for plating automotive fasteners shaped from AISI 9255 low carbon, high silicon steel. The objective was to minimize the ionic and organic species present in each step of the plating process. A sulfuric acid solution inhibited with quinine was defined to clean the steel prior to plating. The corrosivity of the solution was examined through electrochemical and weight loss measurements to evaluate the efficiency of the cleaning process at high temperatures and high acid concentrations. An electroless copper coating process was then developed using a simple copper sulfate chemistry inhibited with quinine to extend the possible operating window. Finally, benzotriazole was evaluated as a possible anti-oxidant coating. Accelerated thioacetamide corrosion tests were used to evaluate the corrosion inhibition of benzotriazole on copper coatings.

A sustainable electroless copper coating process was developed for plating automotive fasteners shaped from AISI 9255 low carbon, high silicon steel. The objective was to minimize the ionic and organic species present in each step of the plating process. A sulfuric acid solution inhibited with quinine was defined to clean the steel prior to plating. The corrosivity of the solution was examined through electrochemical and weight loss measurements to evaluate the efficiency of the cleaning process at high temperatures and high acid concentrations. An electroless copper coating process was then developed using a simple copper sulfate chemistry inhibited with quinine to extend the possible operating window. Finally, benzotriazole was evaluated as a possible anti-oxidant coating. Accelerated thioacetamide corrosion tests were used to evaluate the corrosion inhibition of benzotriazole on copper coatings.

A sustainable electroless copper coating process was developed for plating automotive fasteners shaped from AISI 9255 low carbon, high silicon steel. The objective was to minimize the ionic and organic species present in each step of the plating process. A sulfuric acid solution inhibited with quinine was defined to clean the steel prior to plating. The corrosivity of the solution was examined through electrochemical and weight loss measurements to evaluate the efficiency of the cleaning process at high temperatures and high acid concentrations. An electroless copper coating process was then developed using a simple copper sulfate chemistry inhibited with quinine to extend the possible operating window. Finally, benzotriazole was evaluated as a possible anti-oxidant coating. Accelerated thioacetamide corrosion tests were used to evaluate the corrosion inhibition of benzotriazole on copper coatings.

For the successful development of a hyperaccumulating plant sufficient for use in phytoremediation strategies, a thorough understanding of the mechanism of hyperaccumulation is required. A proteomic survey of the response of plants to metal exposure is a step towards this understanding. The frd3-3 metal accumulating mutant of Arabidopsis thaliana and its non-accumulating wildtype parental ecotype, Columbia, were grown hydroponically in growth chamber experiments and exposed to copper in the growth medium. The responses of the global and copper-targeted proteomes were examined both spatially and temporally. Exposure to copper caused a general increase in protein abundance, however, a prolonged exposure to copper that approached toxicity caused a decrease in protein abundance. The protein species differed between the roots of the two genotypes, with more defense- and stress-related proteins, and fewer transport and storage proteins identified in the mutant when compared to the wildtype. Proteomic evidence suggests that in the mutant the uptake and transport of copper ions to the aerial tissues is regulated. The protein expression patterns over time demonstrate a constitutive expression of defense- and stress-related proteins in the mutant, whereas the wildtype expression was one of induction. The constitutive expression of key defense proteins suggests a state-of-readiness for metal exposure in the mutant. The plant response to reactive oxygen species, as a consequence of copper exposure, is important in the overall metal accumulation mechanism. A suppression of the oxidative burst produced upon exposure to heavy metals is suggested by the proteomic evidence.

The development of reactive organometallics has become a vital part synthetic chemistry. Organosilanes potentially represent a cheap, robust, and environmentally benign precursor to reactive organometallics, but the nature of the very stable C−Si bond has generally prevented their use as precursors to more reactive organometallics. We present investigations into copper fluoride complexes which activate organosilanes in anhydrous media under mild conditions, effecting transmetalation to produce stable and in some cases isolable organocopper species containing sensitive functional groups including carbonyl groups, aryl bromides, benzylic chlorides, and alkyl ketones. This discovery allows us to better understand the fundamental reactivity of presumed intermediates in copper-catalyzed reactions and to develop new catalytic bond-forming processes including allylations of aldehydes, 1,4-addition of vinyl epoxides, and intramolecular ring closures.

The trend to miniaturize electronic devices has led to the development of new fabrication processes. Copper electrodeposition has been used extensively in the fabrication of microelectronic circuits due to the excellent conducting properties of this metal. Control of the operating conditions and understanding of the mechanism of metal deposition is necessary in order to successfully produce the micron–scale features required in these new devices. The implementation of new processes and operating conditions in the fabrication of microelectronic devices has spurred a considerable amount of research into their understanding and improvement. An approach to achieve the desired electrodeposits is the incorporation of mixtures of chemical additives into the electroplating solutions. Many modeling and experimental studies have been devoted to exploring the mechanisms by which additives operate. However, details of these mechanisms are not completely understood. A part of this study focuses on the investigation of the conditions and dynamics of the adsorption and desorption of the additives chloride ions and polyethylene glycol (PEG) on copper substrates in voltammetry and multi–step voltammetry–chronoamperometry experiments. Voltammetry scans are classified into three categories according to the range of potentials where the inhibition of Cu2+ reduction in the presence of various concentrations of Cl− and PEG is observed. Each type is explained based on the results of this study and the ideas presented in the literature on how the conformation of adsorbed PEG on the substrate can change during the course of deposition. One of the techniques that is widely used to study electrochemical processes is electrochemical impedance spectroscopy (EIS). Insight into these processes gained from measured EIS data is better when it is combined with the use of a physicochemical model. However, the models typically used involve a number of simplifying assumptions, partly due to mathematical complications. One of the purposes of this study is to relax some of these assumptions such as the neglect of convection, migration and homogeneous reactions and investigate their effect by comparing the model results to experimental data. This approach is applied to Cu2+ reduction onto a rotating disk electrode in acidic additive–free solutions. Estimates of the kinetic parameters are obtained with the non-linear least squares method. A statistical analysis reveals that the model is further improved by accounting for the correlation between consecutive residuals. The experimental data are found to be poorly predicted when the parameters estimated from the full model are used in simpler models that do not include convection and/or homogeneous reactions. The model of Cu2+ reduction in additive–free solutions is extended to account for the presence of Cl− and PEG under transient conditions. The model accounts for the formation of the inhibiting film, blockage of adsorption sites on the electrode surface and displacement of the inhibiting film by depositing copper. A distinction is made between the condition when the electrode is completely covered with the inhibiting film and when it is only partially covered. Estimates of the kinetic parameters are obtained from fitting the model to electrode responses of linear potential scans obtained at various Cl− and PEG concentrations. The model is able to predict both the sudden loss of inhibition that occurs at intermediate Cl− and PEG concentrations and the more gradual increases in current at low and high additive levels. EIS spectra are also predicted and compared to measured ones.

The trend to miniaturize electronic devices has led to the development of new fabrication processes. Copper electrodeposition has been used extensively in the fabrication of microelectronic circuits due to the excellent conducting properties of this metal. Control of the operating conditions and understanding of the mechanism of metal deposition is necessary in order to successfully produce the micron–scale features required in these new devices. The implementation of new processes and operating conditions in the fabrication of microelectronic devices has spurred a considerable amount of research into their understanding and improvement. An approach to achieve the desired electrodeposits is the incorporation of mixtures of chemical additives into the electroplating solutions. Many modeling and experimental studies have been devoted to exploring the mechanisms by which additives operate. However, details of these mechanisms are not completely understood. A part of this study focuses on the investigation of the conditions and dynamics of the adsorption and desorption of the additives chloride ions and polyethylene glycol (PEG) on copper substrates in voltammetry and multi–step voltammetry–chronoamperometry experiments. Voltammetry scans are classified into three categories according to the range of potentials where the inhibition of Cu2+ reduction in the presence of various concentrations of Cl− and PEG is observed. Each type is explained based on the results of this study and the ideas presented in the literature on how the conformation of adsorbed PEG on the substrate can change during the course of deposition. One of the techniques that is widely used to study electrochemical processes is electrochemical impedance spectroscopy (EIS). Insight into these processes gained from measured EIS data is better when it is combined with the use of a physicochemical model. However, the models typically used involve a number of simplifying assumptions, partly due to mathematical complications. One of the purposes of this study is to relax some of these assumptions such as the neglect of convection, migration and homogeneous reactions and investigate their effect by comparing the model results to experimental data. This approach is applied to Cu2+ reduction onto a rotating disk electrode in acidic additive–free solutions. Estimates of the kinetic parameters are obtained with the non-linear least squares method. A statistical analysis reveals that the model is further improved by accounting for the correlation between consecutive residuals. The experimental data are found to be poorly predicted when the parameters estimated from the full model are used in simpler models that do not include convection and/or homogeneous reactions. The model of Cu2+ reduction in additive–free solutions is extended to account for the presence of Cl− and PEG under transient conditions. The model accounts for the formation of the inhibiting film, blockage of adsorption sites on the electrode surface and displacement of the inhibiting film by depositing copper. A distinction is made between the condition when the electrode is completely covered with the inhibiting film and when it is only partially covered. Estimates of the kinetic parameters are obtained from fitting the model to electrode responses of linear potential scans obtained at various Cl− and PEG concentrations. The model is able to predict both the sudden loss of inhibition that occurs at intermediate Cl− and PEG concentrations and the more gradual increases in current at low and high additive levels. EIS spectra are also predicted and compared to measured ones.

For the successful development of a hyperaccumulating plant sufficient for use in phytoremediation strategies, a thorough understanding of the mechanism of hyperaccumulation is required. A proteomic survey of the response of plants to metal exposure is a step towards this understanding. The frd3-3 metal accumulating mutant of Arabidopsis thaliana and its non-accumulating wildtype parental ecotype, Columbia, were grown hydroponically in growth chamber experiments and exposed to copper in the growth medium. The responses of the global and copper-targeted proteomes were examined both spatially and temporally. Exposure to copper caused a general increase in protein abundance, however, a prolonged exposure to copper that approached toxicity caused a decrease in protein abundance. The protein species differed between the roots of the two genotypes, with more defense- and stress-related proteins, and fewer transport and storage proteins identified in the mutant when compared to the wildtype. Proteomic evidence suggests that in the mutant the uptake and transport of copper ions to the aerial tissues is regulated. The protein expression patterns over time demonstrate a constitutive expression of defense- and stress-related proteins in the mutant, whereas the wildtype expression was one of induction. The constitutive expression of key defense proteins suggests a state-of-readiness for metal exposure in the mutant. The plant response to reactive oxygen species, as a consequence of copper exposure, is important in the overall metal accumulation mechanism. A suppression of the oxidative burst produced upon exposure to heavy metals is suggested by the proteomic evidence.

The plasma-based etching processes of copper (Cu) and titanium tungsten (TiW) thin films, and the electromigration of the copper lines patterned by above etching processes were studied. Instead of vaporizing the plasma/copper reaction product, a dilute hydrogen chloride solution was used to dissolve the nonvolatile reaction product. The plasma/copper reaction process was affected by many factors including the microstructure of the copper film and the plasma conditions. Under the same chlorine plasma exposure condition, the copper conversation rate and the copper chloride (CuClx) formation rate increased monotonically with the Cu grain size. The characteristics of the Cu etching process were explained by diffusion mechanisms of Cl and Cu in the plasmacopper reaction process as well as microstructures of Cu and CuClx. The Cu chlorination process was also affected by the additive gas in the Cl2 plasma. The additive gas, such as Ar, N2, and CF4, dramatically changed the plasma phase chemistry, i.e., the Cl concentration, and the ion bombardment energy, which resulted in changes of the Cu chlorination rate and the sidewall roughness. TiW thin films, used as the diffusion barrier layer for the Cu film, were reactive ion etched with CF4/O2, CF4/Cl2, and CF4/HCl plasma. Process parameter such as feed gas composition, RF power, and plasma pressure showed tremendous effects on the etch rate and the etch selectivity. The TiW etch rate was a function of the sum of Cl and F concentrations and the ion bombardment energy. Cu/diffusion barrier metal stack was successfully patterned by above plasma etch processes. The electromigration (EM) performance of the Cu lines was evaluated by the accelerated isothermal test. The activation energy of 0.5~0.6 eV and the current density exponent of 2.7 were obtained. Failure analysis showed that both copper-silicon nitride cap layer interface and the copper grain boundary were active diffusion paths. The EM induced stress caused the cap layer crack and affected the reliability of Cu lines. The processes studied in this dissertation can be applied in advanced microelectronic fabrication including large area flexible microelectronics.

The improvement and copper contamination of TFTs in active-matrix liquid-crystal displays (AMLCDs) will be discussed in this thesis. TFT with hydrogenated microcrystalline silicon films (mc-Si:H) came to be the attractive candidate due to its higher mobility and stable characteristics. We deposited mc-Si:H films by inductively coupled plasma chemical vapor deposition system (ICPCVD) to achieve fast deposition rate (4~5 Å /sec) which is faster than the conventional PECVD (around 0.1~1 Å/sec). The crystallization of mc-Si:H films deposited by ICPCVD at low temperature was explained by hydrogen etching model. With modulating the hydrogen dilution and rf power of ICPCVD, we can determine the crystallinity of silicon films. Two ways to increase the crystallinity of silicon films was designed: one is the plasma treatment on surface of substrate, and the other is on seed layer. Both methods increased the crystallinity of silicon films and were explained by hydrogen etching and influence of roughness surface. Besides, we discuss the effects of substrate temperature in crystallinity. Microcrystalline silicon films can be deposited at very low temperature as 250¢J, where we may deposit microcrystalline silicon films on flexible plastics substrate in the future. Additionally, we investigated the effects of copper contamination on active layer of TFTs. High resolution large-area AMLCDs will take copper gate and connection to replace aluminum for lowering the RC decay of aluminum connection. We observed that the mobility and output characteristics of TFTs were decreased with copper contamination which played as traps in the channel of TFTs. Besides, part copper contamination at the surface of a-Si layer would form the chemical oxide and eliminate surface state of channel. Therefore, the off current will be decreased.