In situ observation of the void formation-and-propagation mechanism in solder joints under current-stressing

Lin, Yifan; Hu, Yu; Tsai, Cheng‐Ting; Kao, C. R.; Tu, King‐Ning

doi:10.1016/j.actamat.2005.01.014

Cited by 142 publications

(58 citation statements)

References 15 publications

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“…2,3 The electromigration effect on several types of solder in flip-chip joints has been studied. [4][5][6][7][8] All of the failure points were at the interface between the solder and the thin underbump metallization in the cathode. It was reported that the current crowding at the entrance of the electrical current from the trace to the solder bump will result in the nucleation of a void.…”

Section: Introductionmentioning

confidence: 99%

Electromigration-Induced Void Formation at the Cu5Zn8/Solder Interface in a Cu/Sn-9Zn/Cu Sandwich

Kuo

Lin

2008

Journal of Elec Materi

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The electromigration that occurs in a Cu/Sn-9Zn/Cu sandwich was investigated for void formation at room temperature with 10 3 A/cm 2 . A focused ion beam revealed that voids nucleated at the intermetallic compound (IMC)/ solder interface regardless of the electron flow direction. The needle-like voids initiated at the cathode Cu 5 Zn 8 /solder interface due to the outward diffusion of Zn atoms in the Zn-rich phase and expanded as a result of the surface diffusion of Sn atoms upon current stressing.

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Section: Introductionmentioning

confidence: 99%

Electromigration-Induced Void Formation at the Cu5Zn8/Solder Interface in a Cu/Sn-9Zn/Cu Sandwich

Kuo

Lin

2008

Journal of Elec Materi

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“…[3][4][5] However, the electrical properties and electromigration reliability of the flip-chip package have not yet been completely evaluated. [6][7][8][9][10] The electromigration of the flip-chip solder joint under high current stressing has been an important reliability concern in the solder joint system, due to the increasing required device density and power of the flip-chip package. To meet these increasing performance requirements, the I/O number continues to increase.…”

Section: Introductionmentioning

confidence: 99%

Electromigration Behavior in Sn-37Pb and Sn-3.0Ag-0.5Cu Flip-Chip Solder Joints under High Current Density

Kim

Yoon

et al. 2008

Journal of Elec Materi

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The electromigration of conventional Sn-37Pb and Pb-free Sn-3.0Ag-0.5Cu (in wt.%) solder bumps was investigated with a high current density of 2.5 9 10 4 A/cm 2 at 423 K using flip-chip specimens comprised of an upper Si chip and a lower bismaleimide triazine (BT) substrate. Electromigration failure of the Sn-37Pb and Sn-3.0Ag-0.5Cu solder bumps occurred with complete consumption of electroless Ni immersion Au (ENIG) underbump metallization (UBM) and void formation at the cathode side of the solder bump. Finite element analysis and computational simulations indicated high current crowding of electrons in the patterned Cu on the Si chip side, whereas the solder bumps and Cu line of the BT substrate had a relatively low density of flowing electrons. These findings were confirmed by the experimental results. The electromigration reliability of the Sn-3.0Ag-0.5Cu solder joint was superior to that of Sn-37Pb.

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“…8) Additionally, there have been numerous studies into the EM effect on microstructural evolution by applying a direct current (DC) power supply. [9][10][11] In general, solders stressed with current density above 10 8 AÁm À2 for several hours will trigger EM, 12,13) and so will solders with a lower level of current density. 8,14,15) However, the EM effect can be ignored in the case of alternating current (AC).…”

Section: Introductionmentioning

confidence: 99%

The Role of Eutectic Phase and Acicular Primary Crystallized Zn Phase on Electrification-Fusion Induced Fracture of Sn-<I>x</I>Zn Solder Alloys

2011

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Effect of Sn-xZn solder alloys with varying eutectic phase and acicular primary crystallized Zn phase on the electrification-fusion induced liquidation phenomenon was investigated in this study. The critical fusion current density (CFCD) for liquidation fracture tends to increase with increasing Zn content, the CFCD value required for electrification-fusion induced liquidation are 1457 (Â10 4 ) AÁm À2 (7Zn), 1504 (Â10 4 ) AÁm À2 (30Zn) and 2195 (Â10 4 ) AÁm À2 (70Zn) respectively, which are commonly larger than pure tin (1399 (Â10 4 ) AÁm À2 ) pertaining to the transformation of current path. Through the in-situ examination of microstructural evolution during electrification-fusion tests, the initial site of electrification-fusion-induced liquidation significantly emerged from Sn/Zn eutectic phase. From the experimental evidences, it should be noted that the pure Sn specimen showing a character that the initiation site for microliquidation were located at the triple junction of electrification induced current path, whereas the Sn-Zn alloy specimens were commonly initiated from the eutectic phase pertaining to the higher conductivity of acicular Zn phase.

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In situ observation of the void formation-and-propagation mechanism in solder joints under current-stressing

Cited by 142 publications

References 15 publications

Electromigration-Induced Void Formation at the Cu5Zn8/Solder Interface in a Cu/Sn-9Zn/Cu Sandwich

Electromigration-Induced Void Formation at the Cu5Zn8/Solder Interface in a Cu/Sn-9Zn/Cu Sandwich

Electromigration Behavior in Sn-37Pb and Sn-3.0Ag-0.5Cu Flip-Chip Solder Joints under High Current Density

The Role of Eutectic Phase and Acicular Primary Crystallized Zn Phase on Electrification-Fusion Induced Fracture of Sn-<I>x</I>Zn Solder Alloys

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