Browsing by Subject "Aluminum films"
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Item Ellipsometric techniques for determining oxide layer thickness on aluminum.(Texas Tech University, 1975-05) Lydon, Malcolm WebbEllipsometry is an optical tool used for measuring the thickness of extremely thin films. Ordinarily, useful results can be obtained only for very smooth layers of uniform thickness. This study describes an attempt to employ ellipsometric techniques to rough, non-uniform layers such as the natural oxide layers on ALCLAD, an aircraft aluminum. The method uses the formulas pertinent to ellipsometry on ideal layers, but interprets the layer thickness and the substrate conductivity in a phenomenological fashion. Traditional ellipsometric procedures are followed and the data obtained from a sample are plotted on a coordinate system derived from the parameters for ideal oxide layers on ideal aluminum, with substrate conductivity serving as a phenomenological parameter. Once the data have been plotted, values can be determined for the effective layer thickness and effective substrate conductivity. From features of internal consistency, it appears that the obtained parameters characterize the ALCLAD samples in a useful way.Item Study of advanced low pressure seed aluminum film(Texas Tech University, 2003-08) Nallani, Gokul KiranAluminum has emerged as the most important material for interconnects applications because of its low resistivity (p AI - 2.7 |LiQ-cm), and its compatibility with Si and Si02, Sputtering is commonly employed for depositing Al interconnects, which consists mainly of Al slab and Al fill for vias. One such sputtering technique which uses innovative magnetron design called ALPS (Advanced low Pressure Seed) Al is studied. We studied the properties of the deposited film (resistivity, thickness), and the various process conditions under which the film has been deposited. In order to find and optimize the parameters that affect the thickness uniformity, a Design of Experiments (DOE) is implemented. Various parameters are found and optimized which improved the thickness uniformity. Also variation of the Resistivity of the deposited Al film is analyzed across the film and how the annealing improves the resistivity is studied. 12" wafers were employed for all processes.