US Patent 7368379 Multi-layer interconnect structure for semiconductor devices

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.