Atom probe tomography enables elemental distribution analysis in various regions in semiconductor-device related materials. This paper introduces the segregation and precipitation of impurities on specific grain boundaries in Si, and the Cu diffusion suppression effect of additive elements in Cu interconnect layers.

Mechanical property evaluations using compression testing of electrodeposited metals with micron-sized specimens are reviewed. Combination of uniformly shaped specimens and accurate micro-testing method enables evaluation of small specimens for MEMS components. The micro-testing on nickel and gold alloys plated by using electrodeposition method showed high strength indicated the importance of nanocrystalline structures with prolonged Hall-Petch relationships by alloying.

The electrochemical properties of Cu electroplating with supercritical CO₂ (Sc-CO₂) emulsion mixed into the plating solution are reviewed. A rotating disk electrode (RDE), capable of operating under high pressure, was prepared for the electrochemical evaluation by convection voltammetry and electrochemical impedance spectroscopy (EIS) measurements. In the mass transfer process, it was confirmed that the mixture of Sc-CO₂ and plating solution promoted the transport of Cu ions by convection. In the electrode activation reaction process, in addition to the increase in polarization resistance due to the adsorption of the polyethylene glycol (PEG) complex, Sc-CO₂ was found to increase the polarization resistance and further suppress deposition.

This review paper introduces recent progress on metallization of electrically non-conductive materials by a supercritical CO₂ (ScCO₂) assisted metallization for design of novel electronic devices. In Ni-P metallization of polyethylene terephthalate (PET) textiles, ScCO₂ is used as the solvent in the catalyzation step to allow formation of catalyst seeds inside the PET structure. This eventually promotes interactions between the Ni-P coating and the PET surface. In Ni-P metallization of nylon 6,6 textile, ScCO₂ is used as the solvent in the catalyzation step and functions with surfactants to emulsify the electroless plating solution in the metal deposition step. Integration of biocompatible Pt and silk textiles is achieved by the ScCO₂ metallization toward components in biomedical devices. Lastly, metallization of three-dimensional (3D) printed polymer structures is presented to demonstrate the applicability in fast and low cost fabrication of electronic components.

A supercritical carbon dioxide fluid is a compressive high-pressure medium which has a solvent capability, low diffusivity, zero surface tension, and non-toxicity. It enables to deliver chemical reagent for metal thin film deposition deep into complex features so that a conformal film deposition and filling metal into high-aspect holes. The uniqueness of the supercritical carbon dioxide is a key to realize an environmentally-friendly deposition process for future electronic devices.