Abstract
AbstractThe growth orientations of the TiN adhesion layers were controlled by deposition method and film thickness. Preferred growth orientation of conventional PVD deposited TiN thin films was found to vary with the film thickness. For thin film samples (10-50 nm), preferred [100] TiN growth is attributed to the possession of the lowest surface energy among all crystal planes. As the film thickness was increased, the strain energy becomes the dominant factor and leads to preferred [111] TiN growth. For the collimated PVD deposited TiN, only the [100]TiN preferred growth was found. The high power process during collimated PVD deposition is thought to result in the large grain TiN structure, which in turn, impedes the change of preferred orientation. For the as-deposited MOCVD TiN film, the crystal structure was found to be amorphous because of the high carbon contamination in the sample. The carbon contamination was reduced by intermittent in-situ plasma treatment. The preferred growth orientation of the plasma treated MOCVD TiN film was [100]TiN, which is attributed to the relief of stress during the plasma treatment and the surface energy factor is dominating the film growth. The structure and electrical properties of chemical vapor deposited W (CVD-W) films on various physical vapor deposited or metal-organic chemical vapor deposited TiN ( PVD or MOCVD TiN) films have been investigated. The growth orientations of the TiN adhesion layers were controlled by deposition method and film thickness. The growth orientations of CVD-W films were found to depend strongly on the microstructures of TiN. The grain size and electrical resistivity of CVD-W were found to increase and decrease, respectively, with the grain sizesof underlying TiN layers.The alleviation of cracking of TiN-ARC layer on Al-Cu and Al-Cu-Si films after development process has been achieved. For the TiN-ARC/Al-Cu system, the stress induced defects were reduced with the increase in TiN-ARC layer thickness. In contrast, for the TiN-ARC/Al-Cu-Si system, Si nodules formed during cooling induced poor coverage of high aspect ratio holes. As a result, the photoresist developer penetrated through the films. CVD deposition of TiN-ARC or the predeposition of Ti interposing layer was used to eliminate the formation of Si nodules. An ultra thin TiN seed layer was used to reduce the transformation temperature of C-49 to C-54 TiSi2. The fine-grained structure of C-49 TiSi2 was induced by the TiN interposing layer. Since C-54 TiSi2 nucleated more easily in the fine-grained C-49 structure, the phase transformation temperature was reduced as a result. Morphological stability of Ag thin film on both Si substrate and TiN layer with a thin interposing metal layer has been investigated. Owing to the formation of Ag spikes at the Ag/Si interface, a diffusion barrier is needed to buffer the interdiffusion of Ag with Si. TiN films deposited by physical vapor deposition (PVD) or metalorganic chemical vapor deposition (MOCVD) were used. Au or Ti (~3 nm) layer was used as the glue layer between Ag and TiN. In Ag/Au/TiN system, mixed Ag-Au layer is stable on PVD-TiN at a temperature as high as 450 ℃. In Ag/Ti/TiN systems, the thermal stability of Ag on CVD-TiN is superior to that on PVD-TiN. Ag layers were found to be discontinuous after annealing at 300 ℃ and 350 ℃ on PVD-TiN and CVD-TiN systems, respectively.