A method for controlling the position of air gaps in intermetal dielectric
layers between conductive lines and a structure formed using such a
method. A first dielectric layer is deposited over at least two features
and a substrate and an air gap is formed between the at least two
features and above the feature height. The first dielectric layer is
etched between the at least two features to open the air gap. Then a
second dielectric layer is deposited over the etched first dielectric
layer to form an air gap between the at least two features and completely
below the feature height.