Wickham, M; Dusek, M; Zou, L; Hunt, C (2005) Effect of voiding on lead-free reliability. NPL Report. DEPC-MPR 033

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Abstract

As a result of this work, in which seven different solder pastes from three manufacturers have been evaluated through a range of reflow profiles, end–users can have a high degree of confidence that voiding levels in lead-free solder pastes can be kept below the IPC specified maximum of 25% by area. No paste exhibited voids in any PBGA joint greater than 15% despite attempts to produce higher voiding levels.
Three different voiding levels were produced and samples subsequently subjected to 2000 thermal cycles (-55 to +125ºC). Despite these samples having higher voiding levels than those stipulated for class 3 of the IPC’s BGA Assembly and Inspection Guidelines, no adverse effect on reliability was seen. The shear strength deterioration during thermal cycling of chip resistors also with these levels of voiding, was also unaffected.

Item Type:	Report/Guide (NPL Report)
NPL Report No.:	DEPC-MPR 033
Subjects:	Advanced Materials Advanced Materials > Electronics Interconnection
Last Modified:	02 Feb 2018 13:16
URI:	http://eprintspublications.npl.co.uk/id/eprint/3269

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