Effect of flux functional group for solder paste formulation towards soldering quality of SAC305/CNT/Cu

• Main Authors: Ismail, Norliza, Jalar, Azman, Abu Bakar, Maria, Ismail, Roslina, Ibrahim, Najib Saedi
• Format: Article
• Published: Emerald Group Publishing Ltd 2020
• Subjects: Q Science (General); QC Physics
• Online Access: http://eprints.um.edu.my/36894/
• Institution: Universiti Malaya

Purpose The purpose of this paper is to investigate the wettability and intermetallic (IMC) layer formation of Sn-3.0Ag-0.5Cu (SAC305)/CNT/Cu solder joint according to the formulation of solder paste because of different types of fluxes. Design/methodology/approach Solder pastes were prepared by mixing SAC305 solder powder with different flux and different wt.% of carbon nanotube (CNT). Fourier transform infrared spectroscopy was used to identify functional groups from different fluxes of as-formulated solder paste. The solder pastes were then subjected to stencil printing and reflow process. Solderability was investigated via contact angle analysis and the thickness of cross-sectionally intermetallic layer. Findings It was found that different functional groups from different fluxes showed different physical behaviour, indicated by contact angle value and IMC layer thickness. ``Aromatic contain'' functional group lowering the contact angle while non-aromatic contain functional group lowering the thickness of IMC layer. The higher the CNT wt.%, the lower the contact angle and IMC layer thickness, regardless of different fluxes. Relationship between contact angle and IMC layer thickness is found to have distinguished region because of different fluxes. Thus it may be used as guidance in flux selection for solder paste formulation. Originality/value The quality of solder joint of SAC305/CNT/Cu system, as indicated by contact angle and the thickness of IMC layer formation, depends on existence of functional group of the fluxes.