Mechanical bend fatigue reliability of lead-free and halogen-free PBGA assemblies

Jonnalagadda, Krishna; Qi, Fangjuan; Liu, J.

doi:10.1109/tcapt.2005.853924

Cited by 14 publications

(5 citation statements)

References 5 publications

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“…Mechanical fatigue testing of electrical switches, copper traces, printed circuit board (PCB) laminates as well as solder joints are typically not evaluated for mechanical robustness, but if a solder joint were to succumb to fatigue failure the electrical switch is essentially rendered in-operable. It has even been noted that PCB laminates (a key material that is typically chosen for electrical transmission properties and not mechanical robustness) are most likely a significant factor that influences the overall reliability of electronic assemblies 60 .…”

Section: Resultsmentioning

confidence: 99%

Tailored compliant mechanisms for reconfigurable electromagnetic devices

2023

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Reconfigurable electromagnetic devices, specifically reconfigurable antennas, have shown to be integral to the future of communication systems. However, mechanically robust designs that can survive real-world, harsh environment applications and high-power conditions remain rare to this day. In this paper, the general framework for a field of both discrete and continuously mechanically reconfigurable devices is established by combining compliant mechanisms with electromagnetics. To exemplify this new concept, a reconfigurable compliant mechanism antenna is demonstrated which exhibits continuously tunable performance across a broad band of frequencies. Moreover, three additional examples are also introduced that further showcase the versatility and advanced capabilities of compliant mechanism enabled electromagnetic devices. Unlike previous approaches, this is achieved with minimal part counts, additive manufacturing techniques, and high reliability, which mechanical compliant mechanism devices are known for. The results presented exemplify how compliant mechanisms have the capacity to transform the broader field of reconfigurable electromagnetic devices.

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Section: Resultsmentioning

confidence: 99%

Tailored compliant mechanisms for reconfigurable electromagnetic devices

2023

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“…Therefore, when the brittle halogen-free PCB is led in the assembly process, the mechanical bending fatigue reliability of Pbfree and halogen-free PBGA assembly is dramatically deteriorated as reported by Jonnalagadda et al [2]. Normally, a solder joint is composed of metallization layer, solder ball and IMCs between them, the composition, thickness, morphology and dispersion of IMC phases significantly influence the solder joint reliability [3], therefore the optimal thickness of IMC layers has been widely discussed, and Brown [4] has pointed out that 1 um thick Cu-Sn IMC layer provides the optimal solder joint strength in Pb-free assembly.…”

Section: Introductionmentioning

confidence: 95%

Influence of intermetallic compound on the stress distribution and fatigue life of halogen-free printed circuit board assembly

Chang

Zhan

et al. 2009

2009 4th International Microsystems, Packaging, Assembly and Circuits Technology Conference

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A complete halogen-free test vehicle was achieved by assembling five ball grid array (BGA) components with daisy-chain on an 8layer high density interconnection (HDI) printed circuit board with a low-halide Sn1.0Ag0.5Cu (SAC105) Pb-free solder pastes for reducing the formation of Ag 3 Sn. Afterward a board-level cyclic bending test was enforced on the as-reflowed assemblies according to the JESD22-B113 standard to evaluate the reliability of HF PCBA under a low-level load condition. The Weibull analyses showed that the characteristic lives of the assemblies were 99,098 and 130,290 cycles on Cu pad and electroless Ni pad, respectively, and the failure mode was the fracture of Cu trace within the micro-via induced by the crack of resin coated copper (RCC) layer. At the interfaces of solder joints, the intermetallic compound (IMC) formed on both Cu and electroless Ni was (Cu, Ni) 6 Sn 5 with various Ni contents of 3.9 and 20.1 at%, respectively, and different thicknesses of 5.6 and 1.1 um. The simulation results pointed out that the factors of composition and thickness of IMC significantly influenced the stress distribution and characteristic life of the HF test vehicle. The stiff (Cu, Ni) 6 Sn 5 constrained the deformation of solder joint interconnection, but increased the stress concentrated on soldering pad and RCC layer. Although the (Cu, Ni) 6 Sn 5 on the electroless Ni was stiffer than that on the Cu pad, the thicker (Cu, Ni) 6 Sn 5 instead increased the stress on the Cu pad due to size effect, and results in a lower characteristic life.

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“…The finite element analyses have been used to evaluate the solder joint fatigue life in a surface mount assembly. Various mechanical bending tests have been used to assess the reliability of the solder joints, most of which combine experimental testing and the finite element method (FEM) (Kim and Lee, 2008; Jonnalagadda et al ., 2005; Tamin et al ., 2007). Several studies have examined the mechanical fatigue reliability of lead and lead-free solder joints (Kim and Lee, 2008), while others considered the halogen-free PCB assembly in cyclic bending (Jonnalagadda et al ., 2005).…”

Section: Introductionmentioning

confidence: 99%

“…Various mechanical bending tests have been used to assess the reliability of the solder joints, most of which combine experimental testing and the finite element method (FEM) (Kim and Lee, 2008; Jonnalagadda et al ., 2005; Tamin et al ., 2007). Several studies have examined the mechanical fatigue reliability of lead and lead-free solder joints (Kim and Lee, 2008), while others considered the halogen-free PCB assembly in cyclic bending (Jonnalagadda et al ., 2005). Researchers have presented an analytical solution for the stress in solder joints of the PCB assembly subjected to mechanical bending (Suhir, 1988; Wong et al ., 2007; Wong and Wong, 2009; Wong and Wong, 2008).…”

Section: Introductionmentioning

confidence: 99%

Investigation and prediction of solder joint failure analysis for ball grid array package subject to mechanical bending environment

Lan

2017

SSMT

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Purpose The purpose of this study was to investigate the changes in solder joint stress when subjected to mechanical bending. The analytical theory pertaining to the stresses in the solder joint between the components (including the molding compound, the chip and the substrate) was described, and the printed circuit board (PCB) with a discontinuity function when the PCB assembly is subjected to mechanical bending was developed. Thus, the findings reported here may lead to a better understanding of the solder joint failure based on the Physics of Failure model. Design/methodology/approach This paper discusses the analytical model for calculating the stress in solder joints, as well as presents a simulation model that can be used for calculating the strain energy density of solder joint. First, the multilayer plate theory is used in discussing the composite material for the component, including the molding compound, the silicon chip and the substrate, or the PCB, including the copper layers, the fiber and the epoxy. Finally, the complete structure of the analytical model developed as a part of this current work is presented. Findings For the analytical model of multilayer structures in which the interconnection layer is discrete, mechanical bending has been modeled with respect to varying silicon chip length. The analytical model that describes the stress of the outermost solder joint experiences is chosen, as this is the typical solder joint failure. The analytical model can be applied to discrete solder joints, which are evaluated by calculating the matrix form. Owing to its use of the matrix equation, the analytical model can be highly combinatorial and thus more capable of calculating the solution. Research limitations/implications The analytical solution based on a simple concept was presented and validated using the finite element model for the stress experienced by solder joints subjected to mechanical bending. To verify that the simulation represents a real PCB case, the authors use the finite element method (FEM) to compare their case with the multilayer plate theory. Owing to the good agreement between the theory and simulation results, the authors conclude that the multilayer plate theory can be correctly applied in multilayer PCB and be used in an analytical model for the PCB assembly subjected to mechanical bending. Practical implications Owing to the good agreement between the theory and simulation results, the authors conclude that the multilayer plate theory can be correctly applied in multilayer PCB and be used in an analytical model for the PCB assembly subjected to mechanical bending. Social implications The analytical model is validated with the FEM model and provides the way to physically examine the solder joint failure mechanism. In this paper, the analytical model is developed as a means to assess the solder joint stress subjected to mechanical bending. Originality/value The analytical model treats the solder joint as discrete and has been successfully validated against the finite element model. The complete structure model (the second analytical model) is presented to discuss the effects of varying silicon chip length on the normal stress in solder joints. When the silicon chip length exceeds to 80 per cent of the total package length, the stress of the outermost solder joint increases rapidly. The design analysis findings have suggested that the failure of the outermost solder joint subjected to mechanical bending on the PCB assembly can be reduced by analyzing the analytical model.

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Mechanical bend fatigue reliability of lead-free and halogen-free PBGA assemblies

Cited by 14 publications

References 5 publications

Tailored compliant mechanisms for reconfigurable electromagnetic devices

Tailored compliant mechanisms for reconfigurable electromagnetic devices

Influence of intermetallic compound on the stress distribution and fatigue life of halogen-free printed circuit board assembly

Investigation and prediction of solder joint failure analysis for ball grid array package subject to mechanical bending environment

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