Title :
Feasibility of Solid State Bonding for Sn-Ag-Cu Solder Bumps in Ambient Air
Author :
Wang, Ying-Hui ; Suga, Tadatomo
Author_Institution :
Tokyo Univ., Tokyo
Abstract :
The feasibility of solid state bonding for low-profiled Sn-3.0Ag-0.5Cu (wt%) solder bumps is confirmed at 25-200degC by thermo-compression bonding (TCB) and surface activated bonding (SAB) in ambient air. 100% bond yield was achieved. The bonding windows of the necessary bonding force and temperature were described. The composite percent on the bonding surfaces was analyzed quantitatively by X-ray photoelectron spectroscopy (XPS). The successful bonding of Sn-Ag-Cu solder bumps in solid state is benefited from dispersing contaminants and oxides. With the activated process to the bonding surfaces prior to the assembly, the thickness of contaminant and oxide layers in SAB is less than 2 nm, which is much smaller than that of TCB. SAB method is much helpful to reduce the necessary bonding force or temperature compared with TCB method.
Keywords :
bonding processes; copper alloys; electronics packaging; photoelectron spectra; silver alloys; solders; surface contamination; tin alloys; SnAgCu; X-ray photoelectron spectroscopy; bonding force; bonding surface analysis; bonding temperature; contaminants; solder bumps; solid state bonding; surface activated bonding; temperature 25 C to 200 C; thermo-compression bonding; Assembly; Bonding forces; Planarization; Plasma temperature; Rough surfaces; Solid state circuits; Surface cleaning; Surface contamination; Surface roughness; Thermal stresses;
Conference_Titel :
Electronic Packaging Technology, 2007. ICEPT 2007. 8th International Conference on
Conference_Location :
Shanghai
Print_ISBN :
978-1-4244-1392-8
Electronic_ISBN :
978-1-4244-1392-8
DOI :
10.1109/ICEPT.2007.4441378
