Impurity determination in narrow copper lines

摘要

The line width dependent copper grain growth is far from well understood. It can be influenced by impurities trapped during plating as well as geometrical constraint. In this paper, we use Time-of -Flight Secondary Ion Mass Spectroscopy (TOFSIMS) combined with other indirect approaches to measure the impurities in narrow copper lines. It is found that the impurity concentration increases with decreasing line width, and is thus consistent with the retardation of grain growth in narrow trenches.