Effect of type of thermo-mechanical excursion on growth of interfacial intermetallic compounds in Cu/Sn-Ag-Cu solder joints

Ghosh, Rituparna and Kanjilal, Anwesha and Kumar, Praveen (2017) Effect of type of thermo-mechanical excursion on growth of interfacial intermetallic compounds in Cu/Sn-Ag-Cu solder joints. In: MICROELECTRONICS RELIABILITY, 74 . pp. 44-51.

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Abstract

This study reports the effect of different types of thermo-mechanical excursion (TME) on growth of intermetallic compound (IMC) layer formed at the interface of Sn-3.0%Ag-0.5%Cu solder and Cu substrate. 1 mm thick solder joints were prepared by reflowing at 270 degrees C for either 60 or 90 s. Solder joints were then exposed to one of the following TME: (i) isothermal aging at 60 degrees C for 48, 96 and 144 h, (ii) thermal cycling between -25 and 125 degrees C for 100, 200 and 400 cycles, and (iii) thermo-mechanical cycling between -25 and 125 degrees C for 100, 200 and 400 cycles, wherein a shear strain of 10% per cycle was imposed on the joint. Finite element analysis (FEA) was performed to ascertain the effects of imposed shear strain and volumetric expansion due to the formation of IMC on the stress field in the solder joint. Irrespective of the type of TME, the thickness of the IMC layer increased with time. However, IMC thickness increased relatively more rapidly under thermo-mechanical cycling condition, indicating strain enhanced coarsening of the interfacial IMC layer. FEA showed that high stresses were generated in the IMC layer and near solder-IMC interface due to the formation of IMC layer as well as imposed external strain, which might then not only enhance the IMC growth kinetics, but also affect the morphology of the IMC layer. (C) 2017 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	MICROELECTRONICS RELIABILITY
Additional Information:	Copy right for this article belongs to the PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy) Division of Physical & Mathematical Sciences > Instrumentation Appiled Physics
Date Deposited:	21 Jul 2017 09:59
Last Modified:	21 Jul 2017 09:59
URI:	http://eprints.iisc.ac.in/id/eprint/57451

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