Reliability testing of WLCSP lead-free solder joints

Chiang, Huann-Wu; Chen, Jun-Yuan; Chen, Ming-Chuan; Lee, Jeffrey C. B.; Shiau, Gary

doi:10.1007/bf02692564

Cited by 18 publications

(3 citation statements)

References 13 publications

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“…Solder interconnection reliability has received an increasing attention during the recent years due to the miniaturization trend of electronic devices as well as the adoption of the lead-free solder alloys. [1][2][3][4][5][6] Numerous studies have been carried out to identify the root causes of failures in electronic devices under different operation conditions. Most often electrical failures are caused by the mismatch in the coefficient of thermal expansion (CTE) between adjoining materials as a consequence of changes of the device temperature due to either internally generated heat dissipation of integrated circuits or chances of external operation temperature.…”

Section: Introductionmentioning

confidence: 99%

Localized recrystallization and cracking of lead-free solder interconnections under thermal cycling

et al. 2011

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The failure mechanism of lead-free solder interconnections of chip scale package-sized Ball Grid Array (BGA) component boards under thermal cycling was studied by employing cross-polarized light microscopy, scanning electronic microscopy, electron backscatter diffraction, and nanoindentation. It was determined that the critical solder interconnections were located underneath the chip corners, instead of the corner most interconnections of the package, and the highest strains and stresses were concentrated at the outer neck regions on the component side of the interconnections. Observations of the failure modes were in good agreement with the finite element results. The failure of the interconnections was associated with changes of microstructures by recrystallization in the strain concentration regions of the solder interconnections. Coarsening of intermetallic particles and the disappearance of the boundaries between the primary Sn cells were observed in both cases. The nanoindentation results showed lower hardness of the recrystallized grains compared with the nonrecrystallized regions of the same interconnection. The results show that failure modes are dependent on the localized microstructural changes in the strain concentration regions of the interconnections and the crack paths follow the networks of grain boundaries produced by recrystallization.

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Section: Introductionmentioning

confidence: 99%

Localized recrystallization and cracking of lead-free solder interconnections under thermal cycling

et al. 2011

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“…The typical reflow time-temperature profile for the lead-free and the lead-based vehicles are as those shown in previous studies. 4,17 The activation temperature and peak temperature for Sn-3Ag-0.5Cu paste are 153.5°C and 243.5°C, respectively, and the reflow cycle is 360 sec. The activation temperature and peak temperature for Pb-bearing vehicles are 152.5°C and 223.5°C, respectively, and the reflow cycle is 380 sec.…”

Section: Methodsmentioning

confidence: 99%

“…Finally, pull test (schematically as shown in Fig. 1) and shear test (schematically as shown in a previous study 17 ) with the loading rate of 0.01 mm/sec were performed on samples to obtain the joint strength as a function of 150°C HTS aging time and as a function of TCT cycling numbers. The failure modes of the pulled samples are also examined and counted using an SEM.…”

Section: Methodsmentioning

confidence: 99%

The effect of Ag content on the formation of Ag3Sn plates in Sn-Ag-Cu lead-free solder

Chiang

Chang

Chen

2006

Journal of Elec Materi

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The formation of Ag 3 Sn plates in the Sn-Ag-Cu lead-free solder joints for two different Ag content solder balls was investigated in wafer level chip scale packages (WLCSPs). After an appropriate surface mount technology reflow process on a printed circuit board, samples were subjected to 150°C hightemperature storage (HTS), 1,000 h aging, or 1,000 cycles thermal cycling test (TCT). Sequentially, the cross-sectional analysis was scrutinized using a scanning electron microscope/energy dispersive spectrometer (SEM/EDX) to observe the metallurgical evolution of the amount of the Ag 3 Sn plates at the interface and the solder bulk itself. Pull and shear tests were also performed on samples. It was found that the interfacial intermetallic compound (IMC) thickness, the overall IMC area, and the numbers of Ag 3 Sn plates increase with increasing HTS and TCT cycles. The amount of large Ag 3 Sn plates found in the Sn-4.0Ag-0.5Cu solder balls is much greater than that found in the Sn-2.6Ag-0.5Cu solder balls; however, no significant difference was found in the joint strength between two different Ag content solder joints.

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Electronic Packaging Structures

Shen¹

2010

Constrained Deformation of Materials

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Reliability testing of WLCSP lead-free solder joints

Cited by 18 publications

References 13 publications

Localized recrystallization and cracking of lead-free solder interconnections under thermal cycling

Localized recrystallization and cracking of lead-free solder interconnections under thermal cycling

The effect of Ag content on the formation of Ag3Sn plates in Sn-Ag-Cu lead-free solder

Electronic Packaging Structures

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