Effect of electromigration on intermetallic compound formation in line-type Cu/Sn/Cu interconnect

• Published in: Journal of alloys and compounds 2010-08, Vol.504 (2), p.535-541
• Main Authors: Chen, L.D., Huang, M.L., Zhou, S.M.
• Format: Article
• Language: English
• Subjects: AGING MECHANISMS; Alloys; ANODES; CATHODES; Condensed matter: structure, mechanical and thermal properties; CONNECTORS (ELECTRICAL); Copper; Cu/Sn/Cu interconnect; Diffusion in solids; Diffusion; interface formation; ELECTROMIGRATION; Exact sciences and technology; FLUXES; Interfacial reaction; Intermetallic compound; INTERMETALLIC COMPOUNDS; Intermetallics; Physics; POLARITY; Solid surfaces and solid-solid interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Tin; Transport properties of condensed matter (nonelectronic)
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2010.05.158

The line-type Cu/Sn/Cu interconnects were used to determine the growth kinetics of interfacial intermetallic compounds (IMCs) under current densities ranging from 5.0 × 10 3 to 1.0 × 10 4 A/cm 2 at 100 and 150 °C, respectively. EM caused a polarity effect, i.e., the IMCs at the anode side were thicker than those at the cathode side. Compared with the aging specimens, the growth kinetics of the IMCs at the anode side during EM was significantly enhanced and still followed the t 1/2 law. The growth behavior of the IMCs at the cathode side was complicated. A growth model of the IMC at the cathode side was established. When the initial interfacial IMCs were very thin, J dis was minute compared with J em + J chem. The inward fluxes were larger than the outward fluxes, and thus the IMCs grew. After the IMCs reached a critical thickness, J dis became lager than J em + J chem. The inward fluxes were less than the outward fluxes, and thus the IMCs decreased in thickness.