Title :
Influence of copper purity on microstructure and electromigration
Author :
Brongersma, S.H. ; Vanstreels, K. ; Wu, Wenchuan ; Zhang, Wensheng ; Ernur, D. ; D´Haen, J. ; Terzieva, V. ; Van Hove, Marleen ; Clarysse, Trudo ; Carbonell, Laureen ; Vandervorst, W. ; De Ceuninck, W. ; Maex, K.
Author_Institution :
IMEC, Leuven, Belgium
Abstract :
Electromigration in copper damascene interconnects is usually associated with interfacial diffusion at the copper/ dielectric barrier interface. In this study, we demonstrate how impurity and microstructural properties of the bulk copper can influence failures at the copper/dielectric barrier interface. Impurity concentrations in the bulk copper were modulated by varying electroplating conditions and the resulting effects on the copper microstructure and electromigration performances were investigated. A higher impurity concentration in the copper was found to increase the formation of microvoids during anneal and reduced the anneal rate which retarded the formation of large grains in the plated films. Both of these effects result in reduced electromigration lifetime with higher impurity level.
Keywords :
chemical interdiffusion; electromigration; grain size; integrated circuit interconnections; bulk copper; copper barrier interface; copper damascene interconnects; copper microstructure; copper purity; dielectric barrier interface; electromigration performances; impurity concentration; impurity concentrations; impurity level; impurity properties; interfacial diffusion; microstructural properties; microvoids formation; plated films; reduced electromigration lifetime; varied electroplating conditions; Annealing; Copper alloys; Dielectrics; Electromigration; Grain size; Impurities; Materials testing; Mechanical factors; Microstructure; Silicon compounds;
Conference_Titel :
Interconnect Technology Conference, 2004. Proceedings of the IEEE 2004 International
Print_ISBN :
0-7803-8308-7
DOI :
10.1109/IITC.2004.1345679
