A technology for efficiently designing an appropriate metal material with strong adhesion to a ceramic material was developed by using a combination of an orthogonal array and a response-surface method, and it was applied to the interface adhesion between metals and an example ceramic, alumina (Al2O3) in nanoscale thin-film devices. In this optimum-design technology, at the first step, important factors that significantly influence the adhesion strength were selected from various factors that

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... aracterize metal materials by using an orthogonal array with molecular simulations. As a result, the short-side and long-side lattice constants a and b were selected from four metal-material factors (a, b, the electronegativity, E, and the surface energy density, S). At the second step, the adhesion strength was described as a function of the selected important factors by using a response-surface method. From this function, the ideally most appropriate values for a and b that made the adhesion strength maximum were obtained. The obtained optimum values for a and b agreed well with the lattice constants of the ceramic (alumina). At the third step, the most appropriate metal material whose lattice constants were close to the optimum values, which were the lattice constants of the ceramic (alumina), was selected by use of the molecular simulation results of lattice constants. As a result, a Pd alloy with Ni, whose lattice constants were almost the same as the optimum values, was selected as the most appropriate metal material with the strongest adhesion to the ceramic (alumina).