Effects of salt spray test on lead-free solder alloy. (September 2016)

• Record Type: Journal Article
• Authors: Guédon-Gracia, A.; Frémont, H.; Plano, B.; Delétage, J.-Y.; Weide-Zaage, K.
• Is Part Of: Microelectronics and reliability. Volume 64(2016)
• Page Start: 242
• Page End: 247
• Publication Date: 2016-09
• Subjects: Solder joints -- Electronic assembly -- Corrosion; Electronic apparatus and appliances -- Reliability -- Periodicals; Miniature electronic equipment -- Periodicals; Appareils électroniques -- Fiabilité -- Périodiques; Équipement électronique miniaturisé -- Périodiques; Electronic apparatus and appliances -- Reliability; Miniature electronic equipment; Periodicals; 621.3815
• DOI: 10.1016/j.microrel.2016.07.034
• Languages: English
• ISSNs: 0026-2714

Abstract

Abstract: This paper starts with a bibliographic survey about solder corrosion and experimental results of the corrosion on lead-free solder balls during salt spray tests. Focus is made on the SnAgCu solder alloy. Ball Grid Array assemblies and "Package on Package" components were put up to 96 h in a salt spray chamber at 35 °C with 5% sodium chloride (NaCl) aqua according to the ASTMB117 -09 standard. The weight is measured during the test. The solder alloys are observed and analysed along the ageing with optical microscope and scanning electron microscope equipped with an energy-dispersive x-ray system. The solder alloy deterioration is visible after 48 h. The microstructure is analysed in order to determine the corroded residues found on the surface solder balls after the salt spray test. Tin oxychloride (Sn(OH)Cl) is found on BGA solder joints after reflow and on PoP solder balls before reflow. The size of the solder balls has an influence on the corrosion state. Finally a method is developed in order to measure the corrosion product growth on the same sample during the salt environment exposure. Highlights: Study of corrosion on lead-free solder balls during salt spray tests SnAgCu solder alloys analysed along the ageing. Tin oxychloride (Sn(OH)Cl) detected as major corrosion product. The size of the solder balls has an influence on the corrosion state.