Evaluating solder paste behaviours through rheological test methods and their correlation to the printing performance
Mallik, S., Schmidt, M., Bauer, R. and Ekere, N.N. (2010) Evaluating solder paste behaviours through rheological test methods and their correlation to the printing performance. Soldering & Surface Mount Technology, 22 (4). pp. 42-49. ISSN 0954-0911 (doi:10.1108/09540911011076871)Full text not available from this repository.
Purpose: To study the rheological behaviours of lead free solder pastes used for flip-chip assembly applications and to correlate rheological behaviours with the printing performance. Design/methodology/approach: A range of rheological characterization techniques including viscosity, yield-stress, oscillatory and creep-recovery tests were carried out to investigate the rheological properties and behaviours of four different solder paste formulations based on no-clean flux composition, with different alloy composition, metal content and particle size. A series of printing tests were also conducted to correlate printing performance. Findings: The results show that in the viscosity test, all solder pastes exhibited a shear thinning behaviour in nature with different highest maximum viscosity. The yield stress test has been used to study the effect of temperature on the flow behaviour of solder pastes. A decrease in yield stress value with temperature was observed. The results from the oscillatory test were used to study the solid and liquid like behaviours of solder pastes. Creep-recovery test showed that the solder paste with smaller particle size exhibits less recovery. Research limitations/implications: More extensive research in needed to simulate the paste-roll, aperture filling and aperture emptying stages of the stencil printing process using rheological test methods.
Practical implications: Implementation of these rheological characterization procedures in product development, process optimization and quality control can contribute significantly to reducing defects in the assembly of flip-chip devices and subsequently increasing the production yield. Originality/value: The study shows how the viscosity, yield-stress, oscillatory and creep-recovery test methods can be successfully used to characterize the flow behaviours of solder paste and also to predict it’s performance during the stencil printing process.
|Uncontrolled Keywords:||solder paste, viscosity, flipchips, rheology, rheological characterisation, lead-free, stencil printing, viscoelasticity.|
|Subjects:||T Technology > TK Electrical engineering. Electronics Nuclear engineering|
|School / Department / Research Groups:||School of Engineering|
School of Engineering > Department of Engineering Systems
School of Engineering > Manufacturing Engineering Research Group
|Last Modified:||08 Mar 2012 14:09|
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