Electromigration of Pb-free solder under a low level of current density

Zhang, J.S.; Chan, Y.C.; Wu, Yiping; Xi, Hongjia; Wu, Fengshun

doi:10.1016/j.jallcom.2007.04.040

Cited by 37 publications

(14 citation statements)

References 18 publications

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“…As the oil temperature was kept at 25°C, the coefficient of convection for heat transfer was calculated to be 990.6 W/(m 2 K) in our previous work. 19 This forced convection heat transfer dissipated the substantial Joule heating effectively.…”

Section: Experimental Procedures and Resultsmentioning

confidence: 99%

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Thermomechanical Stress and Strain in Solder Joints During Electromigration

Zhang

et al. 2009

Journal of Elec Materi

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Thermomechanical stress and strain in the solder joints of a dummy area array package were studied as electromigration occurred. A current density of 0.4 9 10 4 A/cm 2 was applied to this package, constructed with 9 9 9 solder joints in a daisy chain, to perform the electromigration test. After 37 h, the first joint on the path of the electron flow broke off at the cathode, and the first three solder joints all exhibited a typical accumulation of intermetallic compounds at the anode. Different solder joints exhibited dissimilar electromigration states, such as steady state and nonsteady state. Finite element analysis indicated that during steady-state electromigration, although the symmetrical structure produced uniform distributions of current density and Joule heating in all solder joints, the distribution of temperature was nonuniform. This was due to the imbalanced heat dissipation, which in turn affected the distribution of thermomechanical stress and strain in the solder joints. The maximum thermomechanical stress and strain, as well the highest temperature and current crowding, appeared in the Ni/Cu layer of each joint. The strain in the Ni/Cu layer was significant along the z-axis, but was constrained in the x-y plane. The thermomechanical stress and strain increased with advancing electromigration; thus, a potential delamination between the Ni/Cu layer and the printed circuit board could occur.

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Section: Experimental Procedures and Resultsmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] BasaranÕs group studied stress and deformation in solder joints under high current stressing. [21][22][23][24][25][26] This study examined thermomechanical stress and strain in the different solder joints during steady-state electromigration.…”

Section: Introductionmentioning

confidence: 99%

Thermomechanical Stress and Strain in Solder Joints During Electromigration

Zhang

et al. 2009

Journal of Elec Materi

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“…5(c). It was explained that when a solder joint is subjected to a high current density, the drift of metal atoms in the interconnection occurred, which would eventually cause the formation of micro-voids along the cathode side and a pileup or "hillocks"/IMC hill, along the anode side [4,9,45]. Fig.…”

Section: Microstructure Of Solder Joint Under Exposure To Currentmentioning

confidence: 99%

Effects of current density on the formation and microstructure of Sn–9Zn, Sn–8Zn–3Bi and Sn–3Ag–0.5Cu solder joints

Othman¹,

Binh²,

Ismail³

et al. 2012

Intermetallics

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“…[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). 16) With the microminiaturization of electronic devices (e.g., in household appliances), the high density packaging and high speed for electronic signal transmission, high-currentdensity resistant solder could potentially become a trend at high temperature situations.…”

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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Electromigration of Pb-free solder under a low level of current density

Cited by 37 publications

References 18 publications

Thermomechanical Stress and Strain in Solder Joints During Electromigration

Thermomechanical Stress and Strain in Solder Joints During Electromigration

Effects of current density on the formation and microstructure of Sn–9Zn, Sn–8Zn–3Bi and Sn–3Ag–0.5Cu solder joints

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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