Early stage of material movements in eutectic SnPb solder joint undergoing current stressing at 150°C

2007 ◽  
Vol 91 (2) ◽  
pp. 021906 ◽  
Author(s):  
C. E. Ho ◽  
A. Lee ◽  
K. N. Subramanian ◽  
W. Liu
Keyword(s):  
Solder Joint ◽  
Early Stage ◽  
Current Stressing ◽  
Snpb Solder ◽  
Eutectic Snpb

Microstructure evolution during electromigration in eutectic SnPb solder bumps

2004 ◽  
Vol 19 (8) ◽  
pp. 2394-2401 ◽  
Author(s):  
C.M. Lu ◽  
T.L. Shao ◽  
C.J. Yang ◽  
Chih Chen
Keyword(s):  
Failure Mechanism ◽  
Microstructural Evolution ◽  
Microstructure Evolution ◽  
Under Bump Metallization ◽  
Current Stressing ◽  
Solder Bumps ◽  
Snpb Solder ◽  
Cathode Substrate ◽  
Anode Substrate ◽  
Eutectic Snpb

A technique has been developed to facilitate analysis of the microstructural evolution of solder bumps after current stressing. Eutectic SnPb solders were connected to under-bump metallization (UBM) of Ti/Cr-Cu/Cu and pad metallization of Cu/Ni/Au. It was found that the Cu6Sn5 compounds on the cathode/chip side dissolved after the current stressing by 5 × 103 A/cm2 at 150 °C for 218 h. However, on the anode/chip side, they were transformed into (Nix,Cu1-x)3Sn4 in the center region of the UBM, and they were converted into (Cuy,Ni1-y)6Sn5 on the periphery of the UBM. For both cathode/substrate and anode/substrate ends, (Cuy,Ni1-y)6Sn5 compounds were transformed into (Nix,Cu1-x)3Sn4. In addition, the bumps failed at cathode/chip end due to serious damage of the UBM and the Al pad. A failure mechanism induced by electromigration is proposed in this paper.

Solid-State Spalling of Ag3Sn in an Eutectic SnPb Solder Joint with an Ag Thin Film/Ge Cell

2018 ◽  
Vol 47 (9) ◽  
pp. 5625-5631 ◽  
Author(s):  
Xiaoliang Ji ◽  
Rong An ◽  
Chunqing Wang ◽  
Chongyang Cai
Keyword(s):  
Thin Film ◽  
Solid State ◽  
Solder Joint ◽  
Snpb Solder ◽  
Eutectic Snpb

Spalling of Cu-Sn Compound Spheroids in Solder Joints on Si Wafers

1996 ◽  
Vol 445 ◽  
Author(s):  
H.K. Kim ◽  
K.N. Tu
Keyword(s):  
Thin Film ◽  
Solder Joint ◽  
Sandwich Structure ◽  
Solder Joints ◽  
Face To Face ◽  
Snpb Solder ◽  
Eutectic Snpb ◽  
Au Thin Film

AbstractIn reacting eutectic SnPb solder with Ti/Cu and Cr/Cu/Au thin film metallization on Si wafers, we have observed spalling of Cu6Sn5 spheroids when the solder consumes the Cu. The formation of the spheroids is assisted by the ripening reaction among the compound grains. In addition we have observed an asymmetric spalling phenomenon using a sandwich structure, in which two wafers were soldered face-to-face. The spalling occurs predominantly at the interface below the solder joint. It suggests that gravity plays a role.

Electromigration at the high-Pb–eutectic SnPb solder interface

2004 ◽  
Vol 19 (2) ◽  
pp. 550-556 ◽  
Author(s):  
C.L. Lai ◽  
C.H. Lin ◽  
Chih Chen
Keyword(s):  
Composite Solder ◽  
Current Direction ◽  
Eutectic Solder ◽  
Microstructure Change ◽  
Anchoring Effect ◽  
Current Stressing ◽  
Snpb Solder ◽  
High Lead ◽  
Solder Interface ◽  
Eutectic Snpb

The electromigration behavior of the composite solder composed of eutectic and high-lead SnPb was investigated with 5.7 × 104 A/cm2 current stressing. Voids and hillocks were found only within the eutectic solder, and the high-lead solder remained intact. Electromigration was accelerated dramatically at 150 °C, and Pb became the major migration species of eutectic SnPb for the microstructure change at the anode. The polarity of the opposite current direction was also studied. When electrons drift from the eutectic side to the high-lead side, voids occurred at the eutectic–Cu interface whereas hillocks accumulated at the eutectic–high-lead interface. When the current was reversed, voids occurred at the eutectic–high-lead interface whereas hillocks accumulated at the eutectic–Cu interface. The anchoring effect, which results from the attaching of the lead-rich grains in the eutectic solder to the high-lead solder, was considered to retard the electromigration damage only in this current direction.

Electromigration induced microstructure and morphological changes in eutectic SnPb solder joints

2007 ◽  
Vol 22 (11) ◽  
pp. 3265-3272 ◽  
Author(s):  
A. Lee ◽  
C.E. Ho ◽  
K.N. Subramanian
Keyword(s):  
Solder Joints ◽  
Layer Structure ◽  
Morphological Changes ◽  
Intermetallic Layer ◽  
Mass Movement ◽  
Time Duration ◽  
Current Stressing ◽  
Snpb Solder ◽  
Conducting Species ◽  
Eutectic Snpb

Simultaneous direct current stressing with thermal aging accelerates the migration of conducting species resulting in significant microstructural coarsening. Because of the synergistic fields influence, such coarsening begins from the anode and propagates toward the cathode. Prolonged current stressing with 104 A/cm2 at 150 °C causes the inter-lamellar eutectic SnPb to become a two-layer structure, with a Pb-rich layer adjacent to the anode and an Sn-rich layer adjacent to the cathode. This mass movement causes hillock/valley formation, and the extents of such surface undulations increase with increases in the time duration of current stressing as well as with the joint thickness. In thinner solder joints these events occur sooner, although the extents of surface undulations depend on the thickness of joints. In addition, Cu present in the substrate and in the intermetallic layer at the cathode migrates to form Cu6Sn5 within the Sn-rich layer, in a region close to the Pb-rich layer.

Microstructure evolution in Cu pillar/eutectic SnPb solder system during isothermal annealing

2009 ◽  
Vol 15 (5) ◽  
pp. 815-818 ◽  
Author(s):  
Byoung-Joon Kim ◽  
Gi-Tae Lim ◽  
Jaedong Kim ◽  
Kiwook Lee ◽  
Young-Bae Park ◽  
...  
Keyword(s):  
Microstructure Evolution ◽  
Isothermal Annealing ◽  
Cu Pillar ◽  
Snpb Solder ◽  
Eutectic Snpb

Dominant Migration Element in Electrochemical Migration of Eutectic SnPb Solder Alloy

2006 ◽  
Author(s):  
Shin-Bok Lee ◽  
Ja-Young Jung ◽  
Young-Ran Yoo ◽  
Young-Bae Park ◽  
Young-Sik Kim ◽  
...  
Keyword(s):  
Solder Alloy ◽  
Electrochemical Migration ◽  
Snpb Solder ◽  
Eutectic Snpb

Measurement of impact toughness of eutectic SnPb and SnAgCu solder joints in ball grid array by mini-impact tester

2008 ◽  
Vol 23 (5) ◽  
pp. 1482-1487 ◽  
Author(s):  
Yuhuan Xu ◽  
Shengquan Ou ◽  
K.N. Tu ◽  
Kejun Zeng ◽  
Rajiv Dunne
Keyword(s):  
Impact Toughness ◽  
High Speed ◽  
Solder Joints ◽  
Ball Grid Array ◽  
Snagcu Solder ◽  
Snpb Solder ◽  
Impact Tester ◽  
Pull Tests ◽  
The Impact ◽  
Eutectic Snpb

The most frequent cause of failure for wireless, handheld, and portable consumer electronic products is an accidental drop to the ground. The impact may cause interfacial fracture of ball-grid-array solder joints. Existing metrology, such as ball shear and ball pull tests, cannot characterize the impact-induced high speed fracture failure. In this study, a mini-impact tester was utilized to measure the impact toughness and to characterize the impact reliability of both eutectic SnPb and SnAgCu solder joints. The annealing effect at 150 °C on the impact toughness was investigated, and the fractured surfaces were examined. The impact toughness of SnAgCu solder joints with the plating of electroless Ni/immersion Au (ENIG) became worse after annealing, decreasing from 10 or 11 mJ to 7 mJ. On the other hand, an improvement of the impact toughness of eutectic SnPb solder joints with ENIG was recorded after annealing, increasing from 6 or 10 to 15 mJ. Annealing has softened the bulk SnPb solder so that more plastic deformation can occur to absorb the impact energy.

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