Dusek, M; Hunt, C (2005) The analytical model II for predicting solder joint shape and volume impact on life-time. NPL Report. DEPC-MPR 039

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Abstract

The reliability of electronics assemblies is highly dependent on the quality of solder joints, and the latter’s response to temperature excursions. As part of its work to investigate many aspects of lead-free soldering, NPL has an on-going programme to characterise the thermal fatigue in lead-free solder joints. In this programme the effects on joint integrity of thermal cycling, thermal pre-treatment, solder volume, joint design, component types, PCB finishes, and solder alloy are being studied as part of the development of an analytical model for predicting lead-free solder joint reliability. The work encompasses a wealth of data, and although they can be used widely in a comparative sense, in this work (stage 2 of the project) they are also used to extend their usability by fitting to a linear descriptive formula. This approach has been applied to solder joint variables (inc volume, design, component size, stencil thickness) taking the ultimate shear strength of solder joints of chip resistors, after ageing and thermal cycling, as the degradation metric. The analysis showed that of the variables investigated, component size had the strongest effect on joint reliability. The number of thermal cycles also had a major influence, but stencil thickness had only a minor effect. There was no significant influence arising from varying the PCB design or the solderability of the component/PCB finishes.

Item Type:	Report/Guide (NPL Report)
NPL Report No.:	DEPC-MPR 039
Keywords:	lead-free, modelling regression analysis
Subjects:	Advanced Materials Advanced Materials > Electronics Interconnection
Last Modified:	02 Feb 2018 13:16
URI:	http://eprintspublications.npl.co.uk/id/eprint/3369

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