Of Vlsi Technology, The Aluminum Interconnect Etching Study

As a good conductor , Al thin films were widely used in VLSI industry, in this paper, we studied the properties of Al thin films deposited by magnetron sputtering system, and also the optimum etching conditions of Al were presented. In magnetron sputtering system, the substrate temperature which touched on the energy, the adsorption and the coagulation of Al atoms during the formation of thin films had a great influence to the quality of Al thin films. Therefore, the substrate temperature was the main factor which obviously affected the atoms distribution and step coverage of Al thin films. In this paper, the influence of temperature by adjusting some parameters of sputtering system(Varian3290) was studied. When the heating temperature was between 150 ℃~ 250 ℃, the quality of Al thin films we deposited matched the requirement of semiconductor manufacture. With the increasing of the substrate temperature, the thin films were more difficult to be corroded, and the step coverage of the films was better. But if the temperature was higher beyond 300℃, the surface topography was rugged. We also introduced the principle and main parameters of etching of Al thin films, as well as the structure of the etching machine(Applied Materials 8330). The methods of optimizing some main etching parameters, such as etching rate,uniformity, selectivity and polymer, were investigated through many experiments. And the optimized results can be used for adjusting the process parameters such as the power of radio frequency, chamber pressure, gas flow when drifting from desired conditions occurred,and also the optimum etching conditions were presented.