Impact of Isothermal Aging and Sn Grain Orientation on the Long-Term Reliability of Wafer-Level Chip-Scale Package Sn–Ag–Cu Solder Interconnects

Author

Lee, Tae-Kyu ; Zhou, Bite ; Bieler, Thomas R.

Author_Institution

Component Quality & Technol. Group, Cisco Syst., Inc., San Jose, CA, USA

Volume

2

Issue

3

fYear

2012

fDate

3/1/2012 12:00:00 AM

Firstpage

496

Lastpage

501

Abstract

The interaction between isothermal aging and the long-term reliability of wafer-level chip-scale packages with Sn-3.0Ag-0.5Cu (wt%) solder ball interconnects is investigated. On isothermally aging at 100 and 150°C for 500 h and then thermally cycling from 0 to 100°C with 10 min of dwell time, the lifetime of the package is reduced by approximately 29%, depending on the aging condition. The microstructural evolution is observed during thermal aging and thermal cycling using orientation image microscopy. A Sn grain orientation structure transformation is observed. Different mechanisms after aging at various conditions are identified, and their impacts on the fatigue life of solder joints discussed.

Keywords

ageing; chip scale packaging; copper alloys; fatigue; optical microscopy; reliability; silver alloys; solders; tin alloys; wafer level packaging; Sn-Ag-Cu; dwell time; fatigue life; grain orientation; isothermal aging; long-term reliability; orientation image microscopy; solder ball interconnects; temperature 0 degC to 100 degC; temperature 150 degC; thermal cycling; time 500 h; wafer-level chip-scale package; Aging; Electronic packaging thermal management; Isothermal processes; Joints; Reliability; Soldering; Tin; Orientation image microscopy; Pb-free solder; Sn grain orientation; thermal fatigue;

fLanguage

English

Journal_Title

Components, Packaging and Manufacturing Technology, IEEE Transactions on

Publisher

ieee

ISSN

2156-3950

Type

jour

DOI

10.1109/TCPMT.2011.2181169

Filename

6142055