The stress evolution during and after dc magnetron sputter deposition of Cu thin films with thicknesses of 20 and 300 nm and deposited with a constant rate of 0.1nm∕s onto Si (100) substrates is studied for various sputtering pressures (0.05–6 Pa). The stress was determined by means of in situ wafer curvature measurements using an optical two-beam deflection method. To correlate the stress evolution with the microstructure development, microstructure investigations were performed by scanning electron microscopy, atomic force microscopy, and electron backscatter diffraction. The results show the transition from tensile to compressive stress with decreasing sputtering pressure at different stages of the deposition. The features of the stress evolution during the early stage of deposition can be ascribed to the Volmer–Weber mechanism. For thicker films, three regions of the sputtering pressure can be distinguished concerning their effect on the stress evolution. The transition from compressive to tensile stress was correlated with the evolution from a dense to an open microstructure and with increasing surface roughness by increasing sputtering pressure. The results of the stress and microstructure evolution are interpreted in the context of the mechanisms being discussed in the literature.

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The stress evolution during and after sputter deposition of thin Cu–Al alloy films containing 1 and 2 at.% Al onto oxidized Si(100) substrates has been studied up to thicknesses of 300 nm by means of in situ substrate curvature measurements. In order to correlate stress and morphology, the microstructure was investigated by focused ion beam microscopy, scanning electron microscopy, and atomic force microscopy. The evolution of the stress and microstructure of the Cu–Al alloy films is similar to that for sputtered pure Cu films. Film growth proceeds in the Volmer–Weber mode, typical for high mobility metals. It is characterized by nucleation, island, percolation, and channel stages before the films become continuous, as well as lateral grain growth in the compact films. With increasing Al content the overall atom mobility and, thus, the average grain size of the alloy films are reduced. Increase of the sputter pressure from 0.5 to 2 Pa leads to films with larger grain size, rougher surface morphology and higher electrical resistivity.

The stress, growth, and morphology evolution of Al thin films up to 300 nm thick, sputter deposited at a constant rate of 0.04 nm s(-1) onto thermally oxidized Si(100) substrates have been investigated for various sputter pressures in the range from 0.05 to 6 Pa. The stress evolution has been studied during and after the film deposition by means of in situ substrate curvature measurements using an optical two-beam deflection method. In order to obtain insight into the mechanisms of stress generation and relaxation, the microstructure of the films was investigated by scanning electron microscopy, focused-ion-beam microscopy, and atomic force microscopy. The stress evolution during the early stage of deposition of films is consistent with the Volmer-Weber growth mode known for metals with high adatom mobility. For thicker films, the compressive stress increases in the sputter pressure range of 0.05-0.5 Pa, whereas at even higher sputter pressures a transition from compressive to tensile stress takes place. This transition is correlated with a change from a relatively dense to a more porous microstructure characterized by decreasing mass density and increasing electrical resistivity with increasing sputter pressure. The dependence of the stress and microstructure on the sputter pressure can be consistently understood through a combination of the stress mechanisms for vapor and sputter deposited films proposed in the literature.

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