Tin whisker formation on a lead-free solder alloy studied by transmission electron microscopy

Author

Sosiati, H. ; Kuwano, N. ; Hata, S. ; Iwane, Y. ; Morizono, Y. ; Ohno, Y.

Author_Institution

HVEM, Kyushu Univ., Kasuga

fYear

2006

fDate

6-8 Dec. 2006

Firstpage

398

Lastpage

403

Abstract

Tin whiskers grown on a Sn/Cu-plated polyimide (PI)-flexible substrate are a serious problem in electronic industrial application, because the whiskers lead to catastrophic electrical short circuit failures. Here, we report characterization of microstructures in the whiskers grown on a surface of Sn/Cu-plated PI-flexible substrate by cross-sectional transmission electron microscopy (TEM) to analyze the behavior and the formation mechanism of whiskers. The whisker was found to be monocrystalline beta-Sn and grown with the preferred directions of [110] and [101]. The whiskers formed on this tin surface are nucleated and grown by the compressive stress, that is induced externally by insertion of Sn/Cu-plated PI-flexible substrate into the connector.

Keywords

copper alloys; crystal microstructure; solders; substrates; tin alloys; transmission electron microscopy; whiskers (crystal); Sn-Cu; Sn/Cu-plating; TEM; compressive stress; lead-free solder alloy; monocrystalline; polyimide flexible substrate; tin whisker formation; transmission electron microscopy; Circuits; Compressive stress; Electronics industry; Environmentally friendly manufacturing techniques; Industrial electronics; Lead; Microstructure; Polyimides; Tin alloys; Transmission electron microscopy;

fLanguage

English

Publisher

ieee

Conference_Titel

Electronics Packaging Technology Conference, 2006. EPTC '06. 8th

Conference_Location

Singapore

Print_ISBN

1-4244-0664-1

Electronic_ISBN

1-4244-0665-X

Type

conf

DOI

10.1109/EPTC.2006.342749

Filename

4147278