High sputter bias super secondary grain growth initiation (In structures)

Abstract

Super secondary grain growth is initiated in thin copper seed layers on different types of barriers using high copper sputter bias conditions. In contrast to the low sputter bias initiated super secondary grains, which are dominant at room temperature, high sputter bias super secondary grain growth is dominant at elevated temperatures and leads to even bigger grain sizes (in the order of 500 mu m) and a nearly full super grain film coverage independent of the barrier composition/texture underneath. Moreover, by increasing the copper sputter bias conditions, a clear decrease in self annealing time at room temperature was observed. This knowledge is then used in an attempt to initiate super secondary grains in structures. For this purpose, two different methods are proposed in this paper and their efficiency on initiating super grains in structures is tested.