Theoretical Determination of Solvus Curves in Aluminum-Silicon ALUMINUM-ALUMINUM(3) Titanium, Aluminum -ALUMINUM(2) Copper, and Cadmium-Zinc Binary Systems and Investigations of Solid State Reactions in Aluminum-Alloy Conductor Lines as Related to Stress Voiding.
The solvus curves of various Al-rich disordered alloys and the Cd-Zn system are evaluated by combined linear muffin-tin orbital (LMTO) electronic-structure calculations, Debye-Gruneisen analysis and cluster variation method (CVM). With the introduction of the restricted isothermal-isobaric partition function, phase equilibria are determined through equal chemical potentials for each component in all phases. The dependence of solid solubility on hydrostatic pressure is also investigated using this new partition function. The results show excellent agreement with measurements. An "Interface Reaction Model" is proposed to account for the volume loss due to redox reactions taking place along the Al/passivation interface and its role in assisting stress voiding of Al interconnect lines. Using data gained from phase diagram calculations, the volume and stress changes due to compound precipitation from Al-alloy interconnect lines are computed. The role of these changes in relieving or worsening the stress voiding is discussed. Implications from the results of this study would assist in the selection of more reliable materials for conductor lines in IC circuits.
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- Engineering: Materials Science; Engineering: Metallurgy; Physics: Condensed Matter