Life Prediction of High-Cycle Fatigue in Aluminum Bonding Wires Under Power Cycling Test

Abstract

In this paper, a 3-D finite-element (FE) model was established based on real test samples. Coupled electrothermal and thermal-mechanical FE analyses were conducted to analyze the mechanical behavior of bonding wire under cyclic power loading. The current crowding phenomenon may be improved by increasing the wire number. The junction temperature can be decreased by decreasing the joule heat from the current crowding around the bonding wire. The findings suggest that the power module with wire configuration design shall be operated in a higher power load; meanwhile, the identical reliability can be guaranteed. The temperature predicted by the simulation was consistent with the experimental data. Incremental equivalent plastic strain was not observed when the current loading was low. However, the plastic ratio progressively enhanced with the current load. With a high current load, the yielding effect should be considered. Plastic strain dominated the failure mechanism. The concepts of high-and low-cycle fatigue should be incorporated into the life prediction model for modules subjected to low and high current loadings, respectively. After the simulation results were validated with the experimental data, two models for the design of power modules were proposed.

Damage Evolution in Al Wire Bonds Subjected to a Junction Temperature Fluctuation of 30 K

“…Finite element simulations of bond wires during thermal cycling confirm stress concentration at the heel. 37,38 During active power cycling, an exacerbation of this stress state may occur as a result of forces due to the electromagnetic interaction between the wires leading to lateral displacements. 39 Concurrently, the concentration of stress in the aforesaid regions may mean a greater propensity for microstructural restoration in order to achieve a minimised energy state.…”

A Temperature Gradient-Based Potential Defects Identification Method for IGBT Module

“…Fig.10(a) outlines the schematic of a cyclic power load [27]. The cycle period is 20 s: 10s for power on and 10s for power off.…”

Prediction of Bond Wire Fatigue of IGBTs in a PV Inverter under a Long-Term Operation

“…The IGBT power modules are therefore exposed to both stresses with various levels of temperature swings and frequencies. Previous studies have shown three ageing mechanisms on the bond wires: heel fractures (mechanical 6 IEEE TRANSACTIONS ON POWER ELECTRONICS constraints in the wires and fatigue phenomenon due to the deformation related to temperature swings), wire bond lift-off (mechanical stress on Al-Si joints due to the difference in the thermal expansion coefficient between Al and Si) and metallurgical damage (thermo-mechanical stress on Al coming from the difference in the thermal expansion coefficient between Al and Si) [18], [20], [42]. According to the International Electrotechnical Commission (IEC) [43], two types of cycle periods are considered: the sub-second to tens of seconds regime and the minute-range regime.…”