Finite-element stress and strain analysis of tin–silver–copper solders exposed to isothermal ageing at 100°C

Abstract

This research aims to investigate the influence of pre-isothermal aging on the mechanical behaviour of 98.5Sn–1.0Ag-0.5Cu (SAC105) and 96.5Sn–3.0Ag–0.5Cu (SAC305) interconnects using non-linear finite-element simulations. To accomplish this, reliable literature sources are used to gather the material properties (both elastic and inelastic) of the aged SAC solders, which are then appropriately incorporated into the simulation process. Various aging durations, ranging from 1 to 6 months, are analysed. The results of the numerical computations demonstrate that the mechanical response of pre-aged SAC solders, subjected to thermal cycling, is significantly influenced by the ageing process. Specifically, the non-aged SAC305 configuration exhibits lower inelastic deformations and strain energies compared to the SAC105 system, indicating potentially better thermal fatigue performance. However, SAC105 solders generally exhibit greater resistance to aging, leading to lower levels of inelastic strains and strain energies, particularly for shorter aging durations. In general, it is expected that pre-aged SAC105 solders will demonstrate improved thermal fatigue performance compared to aged SAC305 interconnects.

Keywords:

• SAC solders
• pre-isothermal aging
• finite-element analysis
• Anand viscoplasticity
• thermal cycling

Disclosure of interest

The authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding statement

No funding was received.

Data availability statement

Data used in this paper will be made available upon a reasonable request.