Title :
Intermetallic growth between Sn-Ag-(Cu) solder and Ni
Author :
Yang, Seung Taek ; Chung, Yoon ; Kim, Young-Ho ; Hong, B.H. ; Park, K.R. ; Song, H.G. ; Moris, J.W., Jr.
Author_Institution :
Dept. of Mater. Eng., Hanyang Univ., Seoul, South Korea
Abstract :
The intermetallic formation between Sn-Ag-(Cu) solders and metal pads was characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffractometry (XRD). The intermetallic phase formed in the interface between Sn-Ag-Cu and Au/Ni/Cu pad in a tape BGA package is likely to be a ternary compound of Cu-Ni-Sn from EDS analysis. Cu was also segregated in the solder/Ni interface. XRD analysis confirmed that η-Cu6Sn5 type intermetallic phase formed in the interface between Cu containing solders and Ni substrates and Ni3Sn4 intermetallic formed in the Sn-Ag solder/Ni interface. The Cu atoms in the solder seem to diffuse in the solder/Ni interface and to form η-Cu6Sn5 type intermetallic in the Sn-Ag-Cu specimens. The increase in the Cu concentration of the solder increased the intermetallic thickness after reflow
Keywords :
X-ray chemical analysis; X-ray diffraction; assembling; ball grid arrays; copper alloys; diffusion; environmental factors; integrated circuit packaging; interface structure; nickel; reflow soldering; scanning electron microscopy; segregation; silver alloys; tin alloys; Au/Ni/Cu pad; Cu containing solders; Cu diffusion; Cu segregation; Cu6Sn5; CuNiSn; EDS; Ni pad; Ni substrates; Ni3Sn4; Ni3Sn4 intermetallic; SEM; Sn-Ag solder/Ni interface; Sn-Ag-Cu solder; SnAgCu-Au-Ni-Cu; SnAgCu-Ni; X-ray diffractometry; XRD; XRD analysis; energy dispersive spectroscopy; eta-Cu6Sn5 type intermetallic phase; intermetallic formation; intermetallic growth; intermetallic phase; intermetallic thickness; metal pads; scanning electron microscopy; solder Cu concentration; solder reflow; solder/Ni interface; tape BGA package; ternary Cu-Ni-Sn compound; Assembly; Costs; Dispersion; Environmentally friendly manufacturing techniques; Intermetallic; Lead compounds; Scanning electron microscopy; Soldering; Thermal resistance; X-ray scattering;
Conference_Titel :
Electronic Materials and Packaging, 2001. EMAP 2001. Advances in
Conference_Location :
Jeju Island
Print_ISBN :
0-7803-7157-7
DOI :
10.1109/EMAP.2001.983988
