Brittle fracture of Sn-37Pb solder joints induced by enhanced intermetallic compound growth under extreme temperature changes

The sandwich structure Cu/Sn/Cu solder joints with different thicknesses of the solder layers (δ) are fabricated using a reflow solder method. The microstructure and composition of the solder joints are observed and analyzed by scanning electron microscopy (SEM). Results show that the thickness of intermetallic compound (IMC) and Cu concentration in the solder layers increase with the decrease of δ after reflow. During thermal aging, the thickness of IMC does not increase according to the parabolic rule with the increase of aging time; the solder joint thickness affects markedly the growth rate of IMC layer. At the beginning of thermal aging, the growth rate of IMC in the thinner solder joints (δ ≤ 25 μm) is higher than that in the thicker ones (δ ≥ 30 μm). The growth rate of IMC (δ ≤ 25 μm) decreases in the thinner solder joints, while increases in the thicker solder joints (δ ≥ 40 μm) and is nearly invariable when the δ equals to 30 μm with aging time extending. The growth rate of IMC increases first and then decreases after reaching a peak value with the increase of δ in the later stage during aging. The main control element for IMC growth transfers from Cu to Sn with the reduction of size.

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Effect of Mn Nanoparticles on Interfacial Intermetallic Compound Growth in Low-Ag Sn-0.3Ag-0.7Cu-xMn Solder Joints

Journal of Electronic Materials ◽

10.1007/s11664-017-5886-x ◽

2017 ◽

Vol 47 (2) ◽

pp. 1673-1685 ◽

Cited By ~ 2

Author(s):

Y. Tang ◽

S. M. Luo ◽

G. Y. Li ◽

Z. Yang ◽

R. Chen ◽

...

Keyword(s):

Intermetallic Compound ◽

Solder Joints ◽

Intermetallic Compound Growth ◽

Interfacial Intermetallic Compound

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Correlation Between Chemical Reaction and Brittle Fracture Found in Electroless Ni(P)/immersion gold–solder Interconnection

Journal of Materials Research ◽

10.1557/jmr.2005.0246 ◽

2005 ◽

Vol 20 (8) ◽

pp. 1931-1934 ◽

Cited By ~ 37

Author(s):

Yoon-Chul Sohn ◽

Jin Yu

Keyword(s):

Intermetallic Compound ◽

Brittle Fracture ◽

Solder Joint ◽

Chemical Reaction ◽

Solder Joints ◽

Interfacial Fracture ◽

Solder Interconnection ◽

Failure Locus ◽

Electroless Ni ◽

First Time

Occurrence of brittle interfacial fracture at an electroless Ni(P)/immersion gold–solder joint has long been a serious problem not yet fully understood. In our previous report on the electroless Ni(P) [J. Mater. Res.19,2428 (2004)], it was shown that crystallization of the Ni(P) film and growth of the Ni3SnP layer were accelerated after the intermetallic compound (IMC) spalling, and accurate failure locus of the brittle fracture due to so-called “IMC spalling induced microstructure degradation of the Ni(P) film” is presented for the first time in this communication. For Sn–3.0Ag–0.5Cu solder joints, (Ni,Cu)3Sn4and/or (Cu,Ni)6Sn5ternary IMCs formed at the interface, and neither spalling nor interfacial fracture was observed. For Sn–3.5Ag joints, Ni3Sn4compound formed, and the brittle fracture occurred through the Ni3SnP layer in the solder pads where Ni3Sn4had spalled. Since the Ni3SnP layer is getting thicker during or after Ni3Sn4spalling, control of IMC spalling is crucial to ensure the reliability of Ni(P)/solder system.

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