No abstract

No abstract

The water absorption properties of a PE-CVD (plasma-enhanced chemical vapor deposition) fluorine-doped SiO2 film with a low dielectric constant were studied. It was concluded that highly stable F-doped SiO2 film was obtained at F contents from 2.0% to 4.2% (3.2≤k≤3.6) using high-density plasma CVD. However, at F contents higher than 4.2% (k<3.2), the amount of water absorption was markedly increased due to the presence of Si–F bonds, such as Si(–F)2 bonds, which are highly reactive with water. On the other hand, water absorption was observed at every F content for conventional plasma CVD films. Through gas phase component analysis and investigation of the incident ion energy distribution using a quadrupole mass spectrometer, it was confirmed that a high efficiency of gas dissociation and high-energy ion bombardment are the keys to obtaining high-quality films with a high resistance to water absorption.

The interfacial energy of interconnect-metal/barrier-metal interfaces in ultralarge-scale integrations have been investigated numerically by assuming a simple additive interaction potential within a rigid-lattice approximation. The calculation gave some noteworthy results: Al prefers the (111) orientation on a TiN(111) plane, but Cu did not have such a strong preference. Al(111) can be expected to show strong epitaxial growth on VNx(111), as did Cu on Nb(110). On the basis of the calculations, a Cu/Nb bilayered structure was sputter deposited sequentially by dc magnetron sputtering and examined for crystalline orientation by x-ray-diffraction analysis. Cu exhibited strong (111) orientation preference, and a narrow full width at half-maximum in (111) rocking angle around the substrate normal.

Electromigration properties in a single crystalline submicron width aluminum interconnection formed on Si(111) have been examined by resistance change measurements and in situ observations using scanning electron microscopy. It was observed that single crystalline aluminum has an extremely high resistance to electromigration-induced open circuit failures, when compared to polycrystalline copper and aluminum. The mechanism for the high resistance is considered to be a large activation energy, resulting from lattice diffusion. A tendency for void formation to become parallel to the longitudinal direction of the interconnection assisted the life time prolongation.