Grain refinement for improved lead-Free solder joint reliability

Sweatman, K., Mcdonald, S. D., Whitewick, M., Nishimura, T. and Nogita, K. (2013). Grain refinement for improved lead-Free solder joint reliability. In: IPC APEX EXPO Conference & Exhibition 2013: Proceedings. IPC APEX EXPO Conference and Exhibition 2013, APEX EXPO 2013, San Diego, United States, (561-589). 19-21 February 2013.

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Name Description MIMEType Size Downloads
Author Sweatman, K.
Mcdonald, S. D.
Whitewick, M.
Nishimura, T.
Nogita, K.
Title of paper Grain refinement for improved lead-Free solder joint reliability
Conference name IPC APEX EXPO Conference and Exhibition 2013, APEX EXPO 2013
Conference location San Diego, United States
Conference dates 19-21 February 2013
Proceedings title IPC APEX EXPO Conference & Exhibition 2013: Proceedings
Journal name IPC APEX EXPO Conference and Exhibition 2013, APEX EXPO 2013
Place of Publication Bannockburn, IL, United States
Publisher IPC - Association Connecting Electronics Industries
Publication Year 2013
Sub-type Fully published paper
ISBN 9781627485456
Volume 1
Start page 561
End page 589
Total pages 10
Collection year 2014
Language eng
Abstract/Summary The very small solder joints that now account for an increasing proportion of the connections on which modern electronics depends are typically made up of only a few grains, sometimes only a single grain. This combined with the high degree of anisotropy in the mechanical properties of the body-centred tetragonal beta-tin crystal is a significant factor in determining the response of the joint to the strain to which it is subject in service, with consequent implications for reliability. The superior reliability in joints with multiple small grains of random orientation suggests that it would be advantageous if the solder alloy could be made to solidify with that fine grain structure. In the study reported in this paper the effect of trace additions of selected elements on the grain structure of pure tin and lead-free solder alloys was observed. The elemental additions were chosen on the basis of previous research as well as an analysis of relevant binary phase diagrams. Solidification theory suggests that an objective of the addition should be to promote the rapid development of a constitutionally undercooled zone ahead of the advancing solid/liquid interface since this is known to favour the repeated nucleation required to achieve a fine grain structure. The results contribute to the growing body of knowledge on the development of microstructure in lead-free solder alloys.
Subjects 1708 Hardware and Architecture
2208 Electrical and Electronic Engineering
Keyword Lead-free solders
Grain structure
Nucleation
Solidification
Q-Index Code EX
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Conference Paper
Collections: School of Mechanical & Mining Engineering Publications
Non HERDC
 
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Created: Fri, 15 Nov 2013, 01:35:39 EST by Katie Gollschewski on behalf of Scholarly Communication and Digitisation Service