Non-interfacial growth of Cu3Sn in Cu/Sn/Cu joints during ultrasonic-assisted transient liquid phase soldering process

• Published in: Materials letters Vol. 186; pp. 283 - 288
• Main Authors: Zhao, H.Y., Liu, J.H., Li, Z.L., Zhao, Y.X., Niu, H.W., Song, X.G., Dong, H.J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2017
• Subjects: Copper; Grain morphology; Grains; Interconnection; Interfaces; Intermetallic alloys and compounds; Intermetallics; Liquid phases; Nucleation; Soldering; Tin; TLP soldering; Ultrasonic waves; Interfaces; TLP soldering; Grain morphology; Ultrasonic waves; Intermetallic alloys and compounds
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2016.10.017

The non-interfacial growth of Cu3Sn intermetallic compounds (IMCs) in a Cu/Sn/Cu interconnection structure during the ultrasonic-assisted transient liquid phase (TLP) soldering process was investigated. In the traditional TLP soldering process, the Cu3Sn phase always nucleated at Cu6Sn5/Cu interfaces and grew at the expense of the Cu6Sn5 phase and towards the joint centre, eventually forming a full intermetallic joint consisting of a single Cu3Sn phase with columnar grains. While in the ultrasonic-assisted TLP soldering process, the Cu3Sn phase nucleated and grew randomly within the whole joint, the resulting intermetallic joint consisted of a single Cu3Sn phase with equiaxed grains. This anomalous behaviour can be wholly ascribed to the effects ultrasonic on the nucleation and growth mechanisms of Cu3Sn. •A Cu/Cu3Sn/Cu joint can be rapidly formed by ultrasonic-assisted TLP soldering.•The Cu3Sn phase nucleated and grew randomly within the whole joint.•With a 8s ultrasonic bonding time, the joint consisted of full equiaxed Cu3Sn grains.•The middle grain boundary lines observed in conventional TLP bonds was not present.