An interconnect structure for a semiconductor device and its method of
manufacture is provided. The interconnect structure includes a
multi-layer structure having one or more stress-relief layers. In an
embodiment, stress-relief layers are positioned between layers of
electroplated copper or other conductive material. The stress-relief
layer counteracts stress induced by the conductive material and helps
prevent or reduce a pull-back void. For an interconnect structure using
electroplated copper, the stress-relief layer may be formed by
temporarily reducing the electroplating current, thereby causing a thin
film of copper having a larger grain size to be formed between other
layers of copper. The larger grain size typically exhibits more of a
compressive stress than copper with a smaller grain size. The stress
relief layer may also be formed of other materials, such as SIP-Cu, Ta,
SiC, or the like.