The effects of Cu doping in eutectic PbSn solder balls on ENIG substrates

Author

Nguyen, My

Author_Institution

Altera Corp., San Jose, CA, USA

fYear

2005

fDate

31 May-3 June 2005

Firstpage

922

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;

fLanguage

English

Publisher

ieee

Conference_Titel

Electronic Components and Technology Conference, 2005. Proceedings. 55th

ISSN

0569-5503

Print_ISBN

0-7803-8907-7

Type

conf

DOI

10.1109/ECTC.2005.1441382

Filename

1441382