Diamond conditioning was compared to an alternative method, namely high-pressure micro jet ͑HPMJ͒ conditioning, through a series of interlayer dielectric chemical mechanical planarization ͑ILD CMP͒ marathon tests. The two systems were compared individually and in combination on the basis of ILD removal rate ͑RR͒, coefficient of friction ͑COF͒, and the physical appearance of the pad surface ͑both on the top areas as well as inside the grooves͒. Results indicated that diamond conditioning alone was effective in causing RR and COF stability during extended runs, but it could not clean the slurry residues and other by-products from the surface of the pad ͑especially inside the grooves͒. Results also showed that HPMJ conditioning was able to effectively clean the pad surface, despite not providing enough energy to abrade the surface of the pad and maintain constant RR and COF during extended polishing. Based on these findings, a new pad conditioning method based on a combination of diamond and HPMJ conditioning was proposed. Results showed that this new method allowed for stable polish results in terms of RR and COF during extended marathon runs, and also yielded substantially residue-free surfaces, which could extend pad life and reduce wafer-level defect.
We study deformation of N = 2 and N = 4 super Yang-Mills theories, which are obtained as the low-energy effective theories on the (fractional) D3-branes in the presence of constant Ramond-Ramond 3-form background. We calculate the Lagrangian at the second order in the deformation parameter from open string disk amplitudes. In N = 4 case we find that all supersymmetries are broken for generic deformation parameter but part of supersymmetries are unbroken for special case. We also find that classical vacua admit fuzzy sphere configuration. In N = 2 case we determine the deformed supersymmetries. We rewrite the deformed Lagrangians in terms of N = 1 superspace, where the deformation is interpreted as that of coupling constants.
Numerical experiments on two-dimensional convection with or without a vertical magnetic field reveal a bewildering variety of periodic and aperiodic oscillations. Steady rolls can develop a shearing instability, in which rolls turning over in one direction grow at the expense of rolls turning over in the other, resulting in a net shear across the layer. As the temperature difference across the fluid is increased, two-dimensional pulsating waves occur, in which the direction of shear alternates. We analyse the nonlinear dynamics of this behaviour by first constructing appropriate low-order sets of ordinary differential equations, which show the same behaviour, and then analysing the global bifurcations that lead to these oscillations by constructing one-dimensional return maps. We compare the behaviour of the partial differential equations, the models and the maps in systematic two-parameter studies of both the magnetic and the non-magnetic cases, emphasizing how the symmetries of periodic solutions change as a result of global bifurcations. Much of the interesting behaviour is associated with a discontinuous change in the leading direction of a fixed point at a global bifurcation; this change occurs when the magnetic field is introduced.
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