Drop reliability study of PBGA assemblies with SAC305, SAC105 and SAC105-Ni solder ball on Cu-OSP and ENIG surface finish

Zhu, W.H.; Xu, Luhua; Pang, J.H.L.; Zhang, X.R.; Poh, Edith S. W.; Sun, Yi; Sun, A.Y.S.; Wang, C.K.; Tan, Henry

doi:10.1109/ectc.2008.4550202

Cited by 30 publications

(14 citation statements)

References 3 publications

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“…However, the fracture loads for these three SAC alloys became a function of the surface finish when ENIG and electrolytic Ni-Au were used [19]. Drop test reliability was also found to be a function of surface finish in [20,21], where the best performance was observed for the OSP finish.…”

Section: Introductionmentioning

confidence: 83%

“…It was, however, different from the degrading effect of elevated silver reported in Refs. [13,20] for the impact fatigue life of SAC solder joints. The likely reason is that solder fracture initiation is highly localized at the end of the joint whereas fatigue crack growth is associated with the cyclic development and propagation of a relatively large crack-tip damage zone.…”

Section: High Strain-rate Loadingmentioning

confidence: 99%

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Effect of processing parameters on fracture toughness of lead-free solder joints

Nourani

Spelt

2015

Engineering Fracture Mechanics

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Section: Introductionmentioning

confidence: 83%

Section: High Strain-rate Loadingmentioning

confidence: 99%

Effect of processing parameters on fracture toughness of lead-free solder joints

Nourani

Spelt

2015

Engineering Fracture Mechanics

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“…Therefore, high Ag content solder joint has lower drop lifetime in the electronic assembly when subjected to drop impact, which is the testing results given by Amagai et al [12]. The low Ag content solders are mainly used in the portable electronic assembly for handheld electronic products to improve the drop performance of solder joint [12,13].…”

Section: Effect Of Ag Content On Solder Mechanical Properties and Micmentioning

confidence: 82%

Microstructural investigations and mechanical properties of pure lead-free (Sn–3.0Ag–0.5Cu and Sn–4.0Ag–0.5Cu) solder alloy

et al. 2018

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The Lead-free solders (SAC) with low Ag content have been identified as crucial solder to replace the traditional Sn-Pb solder. The main discussion was presented in two major area of microstructural investigation and mechanical properties of SAC305 and SAC405. Composition and microstructure of SAC solder alloys were investigated by an optical microscope and SEM (Scanning Electron Microscopy). Mechanical properties such as tensile tests and hardness test of the lead-free solder alloys have been tested in this research. Different Ag content and constant Cu content of lead-free solder has been considered in this investigation and compare the mechanical properties of SAC305 and SAC405 solders. From this investigation, tensile strength and hardness have been increased with increased of Ag content.

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“…There are many publications reporting that SnAgCu solder joints with low Ag content performed better in drop test of μBGA [3][4][5][6][7][8][9][10][11][12]. In contrast, the performance of SnAgCu solder joints in thermal cycling improved as the Ag content increases [10,[13][14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 94%

Thermal cycling reliability of SnAgCu solder joints in WLCSP

Zeng

Nangia

2014

2014 IEEE 16th Electronics Packaging Technology Conference (EPTC)

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It has been widely reported in the literature that for packages that are required to pass thermal cycling test, the SnAgCu solder joints should have high Ag content. In this study, thermal cycling performance of a wafer level chip-scale package was evaluated with different combinations of high Ag solder (Sn3.9Ag0.6Cu) and low Ag solder (Sn1.2Ag0.5Cu) with thick and thin PCB. It was found that with the low Ag solder ball the package mounted on a thin PCB had better performance. Metallurgical analysis of solder joints, mechanical modeling of the package mounted on boards, and coplanarity measurement of the printed circuit boards were performed to understand the results. Because of the CTE mismatch between PCB and die, PCB warpage resulted in high tensile stress in solder joints in the central area, causing cracking of re-distribution layer Cu. The softer solder alloy Sn1.2Ag0.5Cu helped reduce the stress, leading to better performance in thermal cycling test. IntroductionWafer level chip-scale package (WLCSP) brings benefit to the miniaturization of devices and low cost. Compared to μBGA, the printed circuitry board (PCB) assembly with WLCSP has simpler structure and but greater stress in solder joints. See Fig. 1. In μBGA, Si die is glued on a polymer substrate and wire bonded to the pads on the substrate. Solder balls are between two polymer materials. Since the die is attached on polymer substrate by adhesive, the stress due to mismatch of coefficien of thermal expansion (CTE) between die and polymer substrate can be largely released by the glue and wires. However, for WLCSP, solder balls are placed on die. It is flip chip assembled directly on the PCB. The CTE mismatch between Si die and PCB is much larger than between substrate and PCB in the case of μBGA. The solder balls between die and PCB are under higher stress than the ones between μBGA substrate and PCB. The CTE of RF-4 PCB is about 16 ppm/°C [1], but it is only 2.5 ppm/°C for die [2]. Because of this, underfill encapsulate is recommended for WLCSP to get better package reliability. However, because of

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Drop reliability study of PBGA assemblies with SAC305, SAC105 and SAC105-Ni solder ball on Cu-OSP and ENIG surface finish

Cited by 30 publications

References 3 publications

Effect of processing parameters on fracture toughness of lead-free solder joints

Effect of processing parameters on fracture toughness of lead-free solder joints

Microstructural investigations and mechanical properties of pure lead-free (Sn–3.0Ag–0.5Cu and Sn–4.0Ag–0.5Cu) solder alloy

Thermal cycling reliability of SnAgCu solder joints in WLCSP

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