In this study, we employed Multiple Internal Reflection Infrared Spectroscopy (MIR-IR) to characterize chemical bonding structures of boron doped hydrogenated amorphous silicon (a-Si:H(B)). This technique has been shown to provide over a hundred fold increase of detection sensitivity when compared with conventional FTIR. Our MIR-IR analyses reveal an interesting counter-balance relationship between boron-doping and hydrogen-dilution growth parameters in PECVD-grown a-Si:H. Specifically, an increase in the hydrogen dilution ratio (H2/SiH4) was found to cause the increase in the Si-H bonding and a decrease in the B-H and SiH2 bonding, as evidenced by the changes in corresponding IR absorption peaks. In addition, although a higher boron dopant gas concentration was seen to increase the BH and SiH2 bonding, it also resulted in the decrease of the most stable SiH bonding configuration. The new chemical bonding information of a-Si:H thin film was correlated with the various boron doping mechanisms proposed by theoretical calculations.
Corrosion of aluminum bond pads in wirebonded packages can lead to device reliability issues under the harsh conditions in automotive applications. Corroded Al (aluminum) surface forms a mud-crack type appearance with a relatively very thick aluminum oxide/hydroxide (> 0.1μm) compared to thin protective native aluminum oxide (< 7nm). Various factors contributing to the formation of mud-crack type corrosion are identified. In all cases of mud-crack corrosion observed for packaged devices, Cl (chlorine) was detected on the corroded Al pad. The corrosive impact of high levels of Cl on the Al pad resulting in thick aluminum oxide growth will be discussed. The concentration levels of Cl to form mud-crack corrosion is far beyond the level of ionizable Cl typically present in packaging materials (such as mold compound or organic die attach) so the source of high levels of Cl is due to foreign contamination. The effect of Cl on mud-crack corrosion depends on other factors including pH and applied bias voltage. Corrosion susceptibility is found to be significantly reduced, even in the presence of high levels of Cl, when the pH > 6 and close to the neutral value of a pH of 7. It was also found that Cl is not essential to form mud-crack corrosion. Conditions leading to the corrosion in the absence of Cl are presented. F (fluorine) is a known contaminant in semiconductor processing and its influence on Al pad corrosion is examined. The differences on the impact of F vs. Cl on mud-crack corrosion will be discussed. Corrosion was observed irrespective of the wirebonds in the package (gold (Au) or copper (Cu)). However, the type of bi-metallic contact influences the extent of corrosion. The impact of bi-metallic contact on the mud-crack corrosion will be presented.
Plasma etching and ashing processes on intricate porous low-k dielectrics are known to introduce high levels of defects that may cause serious reliability issues. Post etch cleans to remove polymer residues could also further damage the porous low-k dielectrics. Compounding the difficulty of handling weak porous ULK materials, a lack of sensitive metrology to evaluate such damage is a serious hindrance to systematic development of plasma etching, restoration and cleaning processes. In this paper, a new metrology tool using Multiple Internal Reflection Infrared Spectroscopy (MIR-IR) was developed and tested using silicon wafer based IR waveguides. Our data demonstrates the capability of MIR-IR spectroscopy to monitor removal of thin polymeric post-plasma etch residues from porous low-k dielectrics and characterize plasma-induced dielectric damage.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.