Internal Microstructure Investigation of Tin Whisker Growth Using FIB Technology

• Published in: Journal of electronic materials Vol. 41; no. 8; pp. 2029 - 2034
• Main Authors: Fortier, Aleksandra, Kovacevic, Radovan
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.08.2012; Springer; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electronics; Electronics and Microelectronics; Exact sciences and technology; Growth from solutions; Instrumentation; Materials Science; Methods of crystal growth; physics of crystal growth; Microstructure; Morphology; Optical and Electronic Materials; Physics; Polycrystals; Scanning electron microscopy; Solid State Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; Tin; Whiskers and dendrites (growth, structure, and nonelectronic properties); Sn whisker microstructure; morphology; scanning electron microscopy (SEM); polycrystalline; focused ion beam (FIB); Scanning electron microscopy; Brass; Surface morphology; Titanium nitride; Polycrystals; Copper base alloys; Focused electron beam technology; Focused ion beam technology; Surface states; Thin films; Zinc alloys; Monocrystals; Experimental result; Growth mechanism; Internal structure; Whiskers; Crystal growth from solutions; Reliability; Microstructure
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-012-2065-y

The problem of tin (Sn) whiskers has been a significant reliability issue in electronics for the past several decades. Despite the large amount of research conducted on this issue, a solution for mitigating the growth of whiskers remains a challenge for the research community. Whiskers have unpredictable growth and morphology, and a study of a whisker’s internal structure may provide further insights into the reason behind their complex growth. This study reports on the internal microstructure and morphology of complex-shaped Sn whiskers grown from an electroplated bright Sn layer on brass substrates exposed to ambient and 95% humid environment. The variables analyzed include surface and microstructure conditions of the film, and morphology and internal microstructure of the Sn whiskers using scanning electron microscopy with focused ion beam technology. Experimental results demonstrated that the whiskers with more complex morphology grow primarily from surfaces exposed to a controlled environment, and some of them have traits of polycrystalline growth rather than only single crystalline, as usually known.