A strain range based model for life assessment of Pb-free SAC solder interconnects

Author

Osterman, Michael ; Dasgupta, Abhijit ; Han, Bongtae

Author_Institution

CALCE Electron. Products & Syst. Center, Maryland Univ., College Park, MD

fYear

0

fDate

0-0 0

Abstract

This paper presents a strain based fatigue model for Pb-free SAC (Sn3.9Ag0.7Cu) solder interconnects based on the results of a designed experiment. Testing consists of temperature cycling CLCC packages soldered to printed wiring board under a fixed 100degC temperature range with the mid-point temperature varying between 25 and 75degC. In addition, the dwell (hold) time at the maximum temperature is varied between 15 and 75 minutes. The mean cycles to failure (N₅₀) is related to the strain range using a numerical regression program. This strain-range failure model captures the observed transition point where fatigue life of SnPb solder is greater than Pb-free SAC solder. Further, the model captures the effect of extended dwell and changes in cycle temperature. The model can be used to predict acceleration factors between test and field conditions

Keywords

ceramic packaging; copper alloys; fatigue testing; lead alloys; life testing; silver alloys; solders; tin alloys; 15 to 75 mins; 75 to 100 C; CLCC packages; SnAgCu; SnPb; fatigue life; life assessment; numerical regression program; printed wiring board; solder interconnects; strain range based model; strain-range failure model; thermal cycling; Assembly; Capacitive sensors; Creep; Fatigue; Lead; Life estimation; Predictive models; Temperature distribution; Testing; US Department of Energy;

fLanguage

English

Publisher

ieee

Conference_Titel

Electronic Components and Technology Conference, 2006. Proceedings. 56th

Conference_Location

San Diego, CA

ISSN

0569-5503

Print_ISBN

1-4244-0152-6

Type

conf

DOI

10.1109/ECTC.2006.1645760

Filename

1645760