Fracture reliability concern of (Au, Ni)Sn4 phase in 3D integrated circuit microbumps using Ni/Au surface finishing. (1st July 2016)

• Record Type: Journal Article
• Authors: Liu, Yingxia; Chen, Yi-Ting; Gu, Sam; Kim, Dong-Wook; Tu, K.N.
• Is Part Of: Scripta materialia. Volume 119(2016)
• Page Start: 9
• Page End: 12
• Publication Date: 2016-07-01
• Subjects: Crack -- Kirkendall voids -- Microbump -- Reliability -- (Au, Ni)Sn4; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2016.02.025
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: Au surface finishing on Ni layer in solder joints can lead to the replacement of β-Sn by (Au, Ni)Sn4 phase in microbumps. A thorough crack in (Au, Ni)Sn4 is found after the sample being annealed at 150 °C for 1000 h. Phase transformation of (Au, Ni)Sn4 to Ni3 Sn4 and AuNi2 Sn4 is observed. This transformation will lead to − 10.5% volume shrinkage and may result in tensile stress, which becomes the reason for a thorough crack formation. Kirkendall voids have been found at the interface between Ni3 Sn4 and electroplated Ni layer. Marker movement indicates that there was a dominant Ni diffusing flux. Graphical abstract: