Title :
The effects of Cu doping in eutectic PbSn solder balls on ENIG substrates
Author_Institution :
Altera Corp., San Jose, CA, USA
fDate :
31 May-3 June 2005
Abstract :
Eutectic (63Sn-37Pb) solder balls were doped at varying levels of copper up to 2.0 wt% to determine the effect on the strength of the ball to substrate bond. The test vehicles were fully assembled packages with the Cu-doped solder balls reflowed on electroless nickel immersion gold (ENIG) substrates. Focus is placed on the analysis of the various intermetallic compounds (IMC). SEM and EDX were used to determine the IMC growth rates and compositional analysis as devices were aged up to 1000 hours at 150°C. Ball shear and ball pull tests were performed to determine the effects of the copper dopants as compared to the standard eutectic solder at the component level. 4-point flex testing was employed to determine the dopant´s effectiveness in improving ENIG brittle fracture failures.
Keywords :
ageing; copper alloys; eutectic alloys; lead alloys; mechanical testing; reflow soldering; solders; tin alloys; 1000 hours; 150 C; 4-point flex testing; Cu; ENIG substrates; PbSn; ageing; copper dopants; copper doping; electroless nickel immersion gold substrates; eutectic solder balls; intermetallic compounds; mechanical testing; reflow soldering; Assembly; Bonding; Copper; Doping; Gold; Intermetallic; Nickel; Packaging; Testing; Vehicles;
Conference_Titel :
Electronic Components and Technology Conference, 2005. Proceedings. 55th
Print_ISBN :
0-7803-8907-7
DOI :
10.1109/ECTC.2005.1441382
