Effects of Minor Ni Doping on Microstructural Variations and Interfacial Reactions in Cu/Sn-3.0Ag-0.5Cu-xNi/Au/Ni Sandwich Structures
Source: Journal of Electronic Materials, Volume 39, Number 12, December 2010 , pp. 2544-2552(9)
Abstract:The effects of Ni doping on microstructural variations and interfacial reactions in Cu/Sn-3.0Ag-0.5Cu-xNi/Au/Ni sandwich structures were investigated. The sandwich structures, i.e., Cu/Sn-3.0Ag-0.5Cu/Au/Ni and Cu/Sn-3.0Ag-0.5Cu-0.1Ni/Au/Ni (wt.%), were reflowed and isothermally aged at 150°C for 500 h. The behavior of Ni and Cu migration in the solders before and after aging was investigated using field-emission electron probe microanalysis (FE-EPMA), and the microstructure evolution of the solders with Ni doping was investigated. It was observed that Ni migrated to the board Cu-side, while Cu tended to migrate toward the Ni/Au package side, and two different types of (Cu,Ni)6Sn5 intermetallic compounds (IMCs), one with 19.8 at.% to 23.4 at.% Ni and the other with 1.3 at.% to 6.4 at.% Ni content, were found. Regarding interfacial reactions, it was identified that the local Ni and Cu concentrations affected the formation of (Cu,Ni)6Sn5. Redistribution of Ni and Cu was correlated with the formation mechanism of interfacial (Cu,Ni)6Sn5.
Document Type: Research article
Affiliations: 1: Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan 2: Interconnect Technology Team, Manufacturing Technology Group, Cisco Systems, Inc., San Jose, CA, USA 3: Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan, Email: email@example.com
Publication date: 2010-12-01