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Supercritical CO2 behaves like both a gas and a liquid, and posseses unique features such as nanopenetration capability, high diffusivity, and solvent ability. The technique described in this paper uses the supercritical CO2 as a reaction medium for thin film growth and realizes filling or coating of nanofeatures with conducting metals. In this paper, we demonstrate the possibilities of this technique in Cu and Ru thin film deposition. A basic approach to achieving Cu metallization of deca-nanometer trenches or vias were studied. Ru, a promising material for capacitor electrodes and also a new candidate for the next-generation Cu barrier, was successfully deposited and its deposition characteristics were studied. Filling capability and the possibility of conformal deposition were also demonstrated as well as the fabrication of a Cu\Ru stack.

Hydrogen plasma effects on ultralow-k porous SiCOH dielectrics J. Appl. Phys. 98, 074502 (2005); 10.1063/1.2060935Effect of plasma interactions with low-κ films as a function of porosity, plasma chemistry, and temperature J.Hydrogen-methyl-siloxane-based porous spin-on-glass films were exposed to an oxidative plasma. The plasma exposure resulted in the loss of hydrophobic groups such as Si-H and Si-CH 3 . The formation of silanole groups, the decrease in film thickness, and moisture uptake were also observed. When the substrate was biased during exposure, these tendencies were found to be suppressed.

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Kinetics of deposition of Cu thin films in supercritical carbon dioxide solutions from copper bis͑di-isobutyrylmethanate͒ ͕Cu͓͑CH 3 ͒ 2 CH͑CO͒CH͑CO͒CH͑CH 3 ͒ 2 ͔ 2 ͖, Cu͑dibm͒ 2 ͒, a F-free copper͑II͒ complex, via hydrogen reduction were studied. A flow-type reaction system was employed to control each deposition parameter independently and at a constant value. Apparent activation energies for Cu growth were determined for a temperature range of 200-260°C as a function of hydrogen concentration.The determined values varied from 0.35 to 0.63 eV and decreased as hydrogen concentration increased. At a deposition temperature of 200°C, growth rate followed a Langmuir-type dependence against Cu͑dibm͒ 2 and hydrogen concentrations, showing first-order dependence at lower concentrations and zero-order dependence at higher concentrations. At a higher deposition temperature of 240°C, no saturation in the growth rate was observed. A Langmuir-Hinshelwood-type growth mechanism was discussed, and a rate equation for growth was proposed, taking into account the temperature dependence of both the rate constant of the rate-determining reaction and adsorption equilibrium constants. The hydrogen concentration dependence of the apparent activation energy for Cu growth was discussed with this rate equation.

We consider whether the non-Gaussian scale-dependent halo bias can be used not only to constrain the local form of non-Gaussianity but also to distinguish among different shapes. In particular, we ask whether it can constrain the behavior of the primordial threepoint function in the squeezed limit where one of the momenta is much smaller than the other two. This is potentially interesting since the observation of a three-point function with a squeezed limit that does not go like the local nor equilateral templates would be a signal of non-trivial dynamics during inflation. To this end we use the quasi-single field inflation model of Chen & Wang [1, 2] as a representative two-parameter model, where one parameter governs the amplitude of non-Gaussianity and the other the shape. We also perform a model-independent analysis by parametrizing the scale-dependent bias as a power-law on large scales, where the power is to be constrained from observations. We find that proposed large-scale structure surveys (with characteristics similar to the dark energy task force stage IV surveys) have the potential to distinguish among the squeezed limit behavior of different bispectrum shapes for a wide range of fiducial model parameters. Thus the halo bias can help discriminate between different models of inflation.

A high confinement plasma (including core plasma and edge plasma) produced by using lower hybrid current drive (LHCD) has been obtained on the HT-7 superconducting tokamak. An internal transport barrier in the core plasma was formed. The energy confinement time increases from 14.6 ms (Ohmic (OH) phase) to 24.5 ms (LHCD phase), which is close to the value calculated using the ITER93ELM free scaling law. The confinement factor H 89 increases from 0.78 (OH phase) to 1.42 (LHCD phase). The experimental results were in good agreement with the simulations calculated with a ray tracing code and a two-dimensional Fokker-Planck equation. The edge plasma characteristics around the last closed flux surface were investigated using Langmuir probes. Turbulence and transport of the edge plasma were suppressed greatly by the lower hybrid wave. Studies show that the enhanced confinement plasma may be ascribed to a shear flow resulting from the shear of the radial electric field.

Supercritical fluid deposition (SCFD) of Cu onto ultranarrow vias (50 to 220 nmφ and 1 µm depth) was studied with using angled polishing for future ultralarge scale integration metallization. SCFD conformally fabricated a smooth, continuous, and 10-nm-thick Cu film in ultranarrow vias. Excess H2 compared with the precursor as well as surface saturation of the precursor enabled uniform nucleation and conformal deposition. Highest H2 concentration in this study (0.39 mol/L) promoted the nucleation density, resulting in formation of a smooth and continuous film. In conclusion, SCFD successfully achieved complete filling without any voids onto via patterns.