Precise Quantitative Evaluation of Nano-Ordered Intermetallic Compounds in Sn-3.0Ag-0.5Cu Lead-Free Solder Bump by Using TEM
The growth behaviour of the intermetallic compounds (IMCs) in Pb-free solder bump is investigated. The Pb-free micro-bump, Sn-50%Bi, was fabricated by binary electroplating for flip-chip bond. The diameter of the bump is about 506m and the height is about 60 6m. In order to increase the reliability of the bonding, it is necessary to protect the growth of the IMCs in interface between Cu pad and the solder bump. For control of IMCs growth, SiC particles were distributed in the micro-solder bump during electroplating. The thickness of the IMCs in the interface was estimated by FE-SEM, EDS, XRF and TEM. From the results, The IMCs were found as Cu6Sn5 and Cu3Sn. The thickness of the IMCs decreases with increase the amount of SiC particles until 4 g/cm2. The one candidate of the reasons is that the SiC particles could decrease the area which be reacted between the solder and Cu layer. And another candidate is that the particle can make to difficult inter-diffusion within the interface.
Alan K.T. Lau, J. Lu, Vijay K. Varadan, F.K. Chang, J.P. Tu and P.M. Lam
C. W. Lee et al., "Precise Quantitative Evaluation of Nano-Ordered Intermetallic Compounds in Sn-3.0Ag-0.5Cu Lead-Free Solder Bump by Using TEM", Advanced Materials Research, Vols. 47-50, pp. 907-911, 2008