TY - JOUR
T1 - Current-induced growth of P-rich phase at electroless nickel/Sn interface
AU - Yang, Qiliang
AU - Shang, Panju
AU - Guo, Jing D.
AU - Liu, Zhiquan
AU - Shang, Jian Ku
N1 - Funding Information:
This study was supported by the Chinese Natural Science Foundation under Grant No. 50228101 and the National Basic Research Program of China, Grant No. 2004CB619306. The experimental assistance of J.J. Guo and John Paul Daghfal are greatly appreciated.
PY - 2009/9
Y1 - 2009/9
N2 - The role of high current stressing during growth of the P-rich phase at the electroless Ni/Sn interface was examined by transmission electron microscopy. Prior to current stressing, two layers of Ni12P5, columnar Ni12P5 and noncolumnar Ni12P5 were formed after soldering. Upon electric stressing, the two layers of P-rich phase showed opposite growth patterns at the two opposing electrode interfaces. At the cathode, columnar growth of the P-rich phase was greatly enhanced while growth of the noncolumnar layer was inhibited. By contrast, the opposite was found at the anode where the current stressing promoted the noncolumnar growth but suppressed the growth of the columnar layer. Such a strong polarity effect resulted from directional electromigration of the key reaction species, nickel, to and from the interfacial reaction fronts. As a result of the difference in reaction mechanism, overall growth of the P-rich phase was much faster at the cathode during current stressing.
AB - The role of high current stressing during growth of the P-rich phase at the electroless Ni/Sn interface was examined by transmission electron microscopy. Prior to current stressing, two layers of Ni12P5, columnar Ni12P5 and noncolumnar Ni12P5 were formed after soldering. Upon electric stressing, the two layers of P-rich phase showed opposite growth patterns at the two opposing electrode interfaces. At the cathode, columnar growth of the P-rich phase was greatly enhanced while growth of the noncolumnar layer was inhibited. By contrast, the opposite was found at the anode where the current stressing promoted the noncolumnar growth but suppressed the growth of the columnar layer. Such a strong polarity effect resulted from directional electromigration of the key reaction species, nickel, to and from the interfacial reaction fronts. As a result of the difference in reaction mechanism, overall growth of the P-rich phase was much faster at the cathode during current stressing.
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U2 - 10.1557/jmr.2009.0333
DO - 10.1557/jmr.2009.0333
M3 - Article
AN - SCOPUS:70350161656
VL - 24
SP - 2767
EP - 2774
JO - Journal of Materials Research
JF - Journal of Materials Research
SN - 0884-2914
IS - 9
ER -