A thermal cycling reliability study of ultrasonically bonded copper wires

Arjmand, Elaheh; Agyakwa, Pearl; Corfield, Martin; Li, Jian Feng; Mouawad, Bassem; Johnson, C.M.

doi:10.1016/j.microrel.2016.01.009

Cited by 18 publications

(5 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The relationship between the advancing cracks and the grain structure of the copper can be examined in Figure (C). The copper microstructure is characterized by large grains approximately 50–150 μm in size, as expected for actively brazed copper subjected to prolonged temperature cycles (Arjmand et al ., ), and features deformation twins. To illustrate the propagation paths more clearly, it is helpful to look at another representation, as shown in Figure , of the micrographs in Figure (C) in which grains are annotated and colour‐coded, so that cells belonging to the same grain are more easily identifiable.…”

Section: Resultsmentioning

confidence: 99%

Three‐dimensional damage morphologies of thermomechanically deformed sintered nanosilver die attachments for power electronics modules

Agyakwa

Dai

et al. 2019

Journal of Microscopy

View full text Add to dashboard Cite

Summary A time‐lapse study of thermomechanical fatigue damage has been undertaken using three‐dimensional X‐ray computer tomography. Morphologies were extracted from tomography data and integrated with data from microscopy modalities at different resolution levels. This enables contextualization of some of the fine‐scale properties which underpin the large‐scale damage observed via tomography. Lateral views of crack development are presented, which show networks analogous to mud‐cracks. Crack fronts which develop in the most porous regions within the sintered attachment layer travel across the boundary into the copper substrate. The propagation characteristics of these cracks within the substrate are analysed. Evidence is provided of heterogeneous densification within the sintered joint under power cycling, and this is shown to play a major role in driving the initiation and propagation of the cracks. Examination of the texture (differing levels of X‐ray absorption) of virtual cross‐sectional images reveals the origins of the nonuniformity of densification. Finally, cracks within the sintered joint are shown to have a negligible impact on the conduction pathway of the joint due to their aspect ratio and orientation with respect to the assembly. Lay Description This paper concerns the use of three‐dimensional (3D) X‐ray tomography, a nondestructive technique, to perform cradle‐to‐grave studies of sintered nanosilver die‐attachments under operation. Sintered nanosilver die‐attachments have been proposed as a more reliable and environmentally friendly alternative to solder alloy joints for emerging power electronics module designs. However, their degradation mechanisms are not as well understood. This same sample‐study is about observing how the fine‐scale structure of a sintered attachment evolves and degrades over time. Using 3D tomography affords otherwise infeasible perspectives, such as virtual cross‐sections in the lateral plane of the attachment. These perspectives provide qualitative information which elucidates the degradation mechanisms. They demonstrate, for example, that the structure of the sintered attachment densifies under operation, and a consequence of this is the formation of shrinkage cracks in the most porous regions, much like mud‐cracks. Other imaging techniques (metallographic etching and scanning electron microscopy) have been used in correlation with 3D renderings of these cracks to analyse their propagation and reveal their relationship both with the internal structure of the sintered attachment itself, and the structure of the substrate to which it is joined. It is shown that the cracks develop within the sintered attachment layer and eventually cross over into the substrate. A comparison of two sintered attachments with contrasting bulk porosities allows the effect of initial bond quality on crack development to be examined.

show abstract

Section: Resultsmentioning

confidence: 99%

Three‐dimensional damage morphologies of thermomechanically deformed sintered nanosilver die attachments for power electronics modules

Agyakwa

Dai

et al. 2019

Journal of Microscopy

View full text Add to dashboard Cite

show abstract

“…The outcomes discovered that; ultrasonic welding is an effective technique for manufacturing high-quality welds without interface defects [20], [21]. In addition, Arjmand et al and Khatibi et al have comprehensively presented the failure mode and failure mechanism through microstructure analysis after undergoing the reliability test [22], [23].…”

Section: Ultrasonicmentioning

confidence: 99%

Microstructure Evaluation of Photovoltaic Solar Panel’s Interconnection: A Review

Hamid

Zulkifli

2022

MSF

View full text Add to dashboard Cite

This paper aims to review the methodologies used to conduct microstructure evaluation of the photovoltaic (PV) interconnection. This analysis is important to identify the microstructural properties of the interconnection for failure analysis purposes. The interconnection becomes a major concern towards the efficiency and reliability of PV technology. In this paper, the common techniques used for the interconnection technology such as soldering, conductive adhesive and ultrasonic were presented with the assessment method to identify the failure mode and failure mechanism at the bonding interface. The identification of the failure mode and failure mechanism through visual analysis and conformation of failure phenomenon was important to highlight the risks and develop the countermeasures. The evaluation of microstructure characterization techniques in the electronics and PV industry has been presented by identifying the outcomes of each technique with different reliability tests. The discoveries of failure analysis in the electronics industry were more matured and becomes the reference to the PV development. The outcomes from this review could be beneficial to improve the interconnection bond in the PV industry by eliminating or minimizing the failure through design modification at the earliest point in the development process.

show abstract

“…In the case of wire bonding, however, the situation may differ. According to [35][36][37], the ultrasonically wire bonding could damage the bonds and make them vulnerable, even pre-crack could have been the result. As a consequence, the lifetime of the bond wire could be regarded roughly as the time that propagating to the critical crack length needs.…”

Section: State-space Model Of the Degradation Processmentioning

confidence: 99%

Cost-Effective Prognostics of IGBT Bond Wires With Consideration of Temperature Swing

Liu

et al. 2020

IEEE Trans. Power Electron.

View full text Add to dashboard Cite

This paper presents a cost-effective prognostic method for the bond wires in IGBT. Consider that the crack propagation in the wire bond leads to the bond wire lift-off, the corresponding state equation is established from the fracture mechanics theory, with the consideration of the uneven distribution of the temperature swings. Hence, the proposed model can work under different loading conditions. With the fact that the on-state voltage (vce,on) of the IGBT shifts with the crack propagation, the history vce,on is used to predict the remaining useful lifetime (RUL), through which numerous power cycling tests are avoided, and low economical cost for doing prognosis is fulfilled. In this paper, the functional relationship between the increase of vce,on and the crack length of each bond wire is obtained through finite element simulation, while the effects of the temperature variation and metallization degradation to the vce,on are compensated. Thus, the output equation can be obtained. Then, the unknown parameters of the above equations and the current crack length can be estimated by the particle-based marginalized resample-move algorithm. Finally, the RUL can be predicted effectively by evolving the particles obtained in the algorithm. The proposed method has been validated by the power cycling test. 1

show abstract

A thermal cycling reliability study of ultrasonically bonded copper wires

Cited by 18 publications

References 5 publications

Three‐dimensional damage morphologies of thermomechanically deformed sintered nanosilver die attachments for power electronics modules

Three‐dimensional damage morphologies of thermomechanically deformed sintered nanosilver die attachments for power electronics modules

Microstructure Evaluation of Photovoltaic Solar Panel’s Interconnection: A Review

Cost-Effective Prognostics of IGBT Bond Wires With Consideration of Temperature Swing

Contact Info

Product

Resources

About