Effects of the intermetallic compound microstructure on the tensile behavior of Sn3.0Ag0.5Cu/Cu solder joint under various strain rates

• Published in: Microelectronics and reliability Vol. 54; no. 5; pp. 932 - 938
• Main Authors: An, Tong, Qin, Fei
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-05-2014; Elsevier
• Subjects: AGING MECHANISMS; Applied sciences; Copper; Design. Technologies. Operation analysis. Testing; Electronics; Exact sciences and technology; Failure modes; Integrated circuits; Intermetallic compounds; JOINTS; Microstructure; MICROSTRUCTURES; Roughness; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; SOLDERING ALLOYS; Solders; STRAIN; Strain rate; Tensile strength; Intermetallic compound; Brittle fracture; Ageing; Roughness; Solder metal; Failures; Tensile strength; Integrated circuit bonding; Soldered joint; Lead free soldering; Copper; Microstructure; Strain rate
• ISSN: 0026-2714; 1872-941X
• DOI: 10.1016/j.microrel.2014.01.008

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•The IMC roughness and tensile strength of solder joint has a positive correlation.•The tensile strength has a positive correlation with the strain rate.•Ductile fracture in the bulk solder plays dominant role at the low strain rate.•Brittle facture in the IMC layer plays dominant role at the high strain rate.
The effects of the intermetallic compound (IMC) microstructure and the strain rate on the tensile strength and failure mode of Pb-free solder joints are investigated. The samples of Sn3.0Ag0.5Cu/Cu solder joints are aged isothermally at 150°C for 0, 72, 288 and 500h, and the thickness of the IMC layer and the roughness of the solder/IMC interface are measured and used to characterize the microstructure evolution of the IMC layer. The tensile tests of the aged solder joints are conducted under the strain rates of 2×10−4, 2×10−2 and 2s−1. The results indicate that both the thickness and roughness of the IMC layer have influence on the strength and failure mode of the solder joint. With the increase of the aging time, the thickness of the IMC layer increases and the roughness of the solder/IMC interface decreases, as a result, the tensile strength of the solder joint decreases and the dominant failure mode migrates from the ductile fracture in the bulk solder to the brittle fracture in the IMC layer. There is a positive correlation between the tensile strength of the solder joint and the stain rate applied during the test. With the increase of the strain rate, the failure mode migrates from the ductile fracture in the bulk solder to the brittle fracture in the IMC layer.