Study of advanced low pressure seed aluminum film

Abstract

Aluminum 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.