The influence of porosity on whisker growth in electroplated tin films

2006 ◽  
Vol 21 (12) ◽  
pp. 2971-2974 ◽  
Author(s):  
J.P. Winterstein ◽  
M.G. Norton
Keyword(s):  
Whisker Growth ◽  
Control Method ◽  
Stress Relief ◽  
Lead Free ◽  
Tin Whisker ◽  
Tin Films ◽  
The Past ◽  
Compressive Stresses ◽  
Time Period ◽  
Lead Free Solders

Tin whisker growth has been observed since the 1950s and has become of more interest in the past 15 to 20 years due to the desire to use lead-free solders, pure tin being a good lead-free candidate. In the same time period, failure of satellites and other devices using pure tin solders has been blamed on tin whisker growth. The accepted driving force for whisker growth is compressive stresses in films. This article reports a microstructure-control method of limiting whisker growth through the introduction of pores that permit an alternate means of stress relief.

Corrosion-induced tin whisker growth in electronic devices: a review

2017 ◽  
Vol 29 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Balázs Illés ◽  
Barbara Horváth ◽  
Attila Géczy ◽  
Olivér Krammer ◽  
Karel Dušek
Keyword(s):  
Literature Review ◽  
Whisker Growth ◽  
Electronic Devices ◽  
Lead Free ◽  
Future Research ◽  
Tin Whisker ◽  
Content Type ◽  
The Past ◽  
Surface Finishes ◽  
Inducing Factors

Purpose The aim of this paper is to present a review of the tin whisker growth phenomena. The study focuses mainly on whisker growth in a corrosive climate when the main inducing factor of the whisker growth is oxidation. The tin whisker phenomenon is still a big challenge in lead-free reflow soldering technology. Modern lead-free alloys and surface finishes with high tin content are considered to be possible sources of whisker development, also the evolution of electronic devices towards further complexity and miniaturization points to an escalation of the reliability risks. Design/methodology/approach The present work was based on a worldwide literature review of the substantial previous works in the past decade, as well as on the results and experience of the authors in this field. Findings The effect of corrosion on tin whisker growth has been under-represented in reports of mainstream research; however, in the past five years, significant results were obtained in the field which raised the corrosion phenomena from being a side effect category into one of the main inducing factors. This paper summarizes the most important findings of this field. Practical implications This literature review provides engineers and researchers with a better understanding of the role of corrosion in tin whisker growth and the current challenges in tin whisker mitigation. Originality/value The unique challenges and future research directions about the tin whisker phenomenon were shown to highlight rarely discussed risks and problems in lead-free soldering reliability.

scholarly journals An investigation of tin whisker growth over a 32-year period

Circuit World ◽  
2016 ◽  
Vol 42 (4) ◽  
pp. 183-196 ◽  
Author(s):  
Mark Andrew Ashworth ◽  
Barrie Dunn
Keyword(s):  
Cross Sections ◽  
Whisker Growth ◽  
Tin Whisker ◽  
Content Type ◽  
Intermetallic Formation ◽  
Time Period ◽  
Whisker Length ◽  
Electron Microscopy Analysis ◽  
Long Time ◽  
Tin Plating

Purpose This paper aims to present the results of a 32-year-old laboratory study of whisker growth from tin electrodeposits that was originally undertaken to gain an increased understanding of the phenomenon of tin whisker growth. Design/methodology/approach Whisker growth was evaluated using electroplated C-rings (both stressed and un-stressed) that were stored throughout in a desiccator at room temperature. Analysis has recently been undertaken to evaluate whisker growth and intermetallic growth after 32 years of storage. Scanning electron microscopy analysis has been performed to investigate whisker length and, using polished cross-sections, the morphology, thickness and type of intermetallic formation. Findings Normal tin-plated deposits on brass and steel with a copper barrier layer nucleated whiskers within five months, and in each case, these grew to lengths between 1 and 4.5 mm. For normal tin electroplated onto brass, a one- or two-month nucleation period was needed before whiskers developed. They reached a maximum length of about 1.5 mm after six months, and little or no further growth occurred during the subsequent 32 years. Very few whiskers grew on the tin-plated steel samples and no intermetallic formation was observed. None of the fused tin plating samples nucleated whiskers during the 32-year period. Practical implications Knowledge about vintage whiskers is important to take steps to increase the resiliency of space missions. Similarly, such knowledge is important to engineers engaged in products reaching their nominal end-of-life, but where, for reasons of economy, these products cannot be replaced. Originality/value This study represents a unique insight into whisker growth and intermetallic formation over an extremely long time period.

Topics in Lead-Free Solders: Interfacial and Sn Whisker Growth

JOM ◽  
2012 ◽  
Vol 64 (10) ◽  
pp. 1174-1175 ◽  
Author(s):  
Srinivas Chada
Keyword(s):  
Whisker Growth ◽  
Lead Free ◽  
Sn Whisker ◽  
Lead Free Solders

Electron microscopy study of tin whisker growth

2003 ◽  
Vol 18 (3) ◽  
pp. 585-593 ◽  
Author(s):  
J. B. LeBret ◽  
M. G. Norton
Keyword(s):  
Electron Microscopy ◽  
Whisker Growth ◽  
Intermetallic Phase ◽  
Microscopy Study ◽  
Growth Direction ◽  
Electron Microscopy Study ◽  
Tin Whiskers ◽  
Tin Whisker ◽  
Compressive Stresses ◽  
Whisker Morphology

The growth of tin whiskers formed on sputtered tin layers deposited on brass was studied using electron microscopy. The occurrence of whiskers appeared to be largely independent of the macroscopic stress state in the film; rather it was microscopic compressive stresses arising from the formation of an intermetallic phase that appeared to be the necessary precursor. Whisker morphology was a result of whether nucleation had occurred on single grains or on multiple grains. In the latter case, the whiskers had a fluted or striated surface. The formation of whiskers on electron transparent samples was demonstrated. These samples showed the whiskers were monocrystalline and defect free, and that the growth direction could be determined.

Influence of laminate type on tin whisker growth in tin-rich lead-free solder alloys

2012 ◽  
Vol 177 (15) ◽  
pp. 1286-1291 ◽  
Author(s):  
Agata Skwarek ◽  
Mariusz Pluska ◽  
Andrzej Czerwinski ◽  
Krzysztof Witek
Keyword(s):  
Whisker Growth ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Alloys ◽  
Tin Whisker ◽  
Free Solder

scholarly journals Development of lead-free solders in China during the past decade

2016 ◽  
Vol 46 (8) ◽  
pp. 767-790
Author(s):  
Liang ZHANG ◽  
KingNing TU ◽  
SinnWen CHEN ◽  
Hui FAN ◽  
XiangNing LU ◽  
...  
Keyword(s):  
Lead Free ◽  
The Past ◽  
Lead Free Solders

Analysis of tin whisker growth on lead-free alloys with Ni presence under thermal shock stress

2011 ◽  
Vol 176 (4) ◽  
pp. 352-357 ◽  
Author(s):  
Agata Skwarek ◽  
Mariusz Pluska ◽  
Jacek Ratajczak ◽  
Andrzej Czerwinski ◽  
Krzysztof Witek ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Whisker Growth ◽  
Lead Free ◽  
Tin Whisker ◽  
Shock Stress

The Effects of Dopants on the Aging Behavior of Lead Free Solders

2011 ◽  
Author(s):  
Zijie Cai ◽  
Jeffrey C. Suhling ◽  
Pradeep Lall ◽  
Michael J. Bozack
Keyword(s):  
Elevated Temperature ◽  
Thermal Cycling ◽  
Room Temperature ◽  
Creep Compliance ◽  
Lead Free ◽  
Creep Properties ◽  
The Past ◽  
Free Solder ◽  
Lead Free Solders ◽  
Temperature Aging

The microstructure, mechanical response, and failure behavior of lead free solder joints in electronic assemblies are constantly evolving when exposed to isothermal aging and/or thermal cycling environments. Over the past several years, we have demonstrated that the observed material behavior variations of Sn-Ag-Cu (SAC) lead free solders during room temperature aging (25 C) and elevated temperature aging (50, 75, 100, 125, and 150 C) were unexpectedly large and universally detrimental to reliability. The measured stress-strain data demonstrated large reductions in stiffness, yield stress, ultimate strength, and strain to failure (up to 50%) during the first 6 months after reflow solidification. In addition, even more dramatic evolution was observed in the creep response of aged solders, where up to 100X increases were found in the steady state (secondary) creep strain rate (creep compliance) of lead free solders that were simply aged at room temperature. For elevated temperature aging at 125 C, the creep strain rate was observed to change even more dramatically (up to 10,000X increase). There is much interest in the industry on establishing optimal SAC-based lead free solder alloys that minimize aging effects and thus enhance thermal cycling and elevated temperature reliability. During the past year, we have extended our previous studies to include several doped SAC alloys (SAC-X) where the standard SAC alloys have been modified with small percentages of one or two additional elements (X). Materials under consideration include SAC0307-X, Sn-.7Cu-X, SAC305-X, SAC3595-X and SAC3810-X. Using dopants (e.g. Bi, In, Ni, La, Mg, Mn, Ce, Co, Ti, etc.) has become widespread to enhance shock/drop reliability, and we have extended this approach to examine the ability of dopants reduce the effects of aging and extend thermal cycling reliability. In the current paper, we concentrate on showing results for SACX™, which has the composition Sn-0.3Ag-0.7Cu-X with X = 0.1Bi. We have performed aging under 5 different conditions including room temperature (25 C), and four elevated temperatures (50, 75, 100 and 125). We have also extended the duration of aging considered in our experiments to up to 12 months of aging on selected alloys. Variations of the mechanical and creep properties (elastic modulus, yield stress, ultimate strength, creep compliance, etc.) have been observed. We have correlated the aging results for the doped SAX-X alloy with our prior data for the “standard” lead free alloys SACN05 (SAC105, SAC205, SAC305, SAC405). The doped SAC-X alloy shows improvements (reductions) in the aging-induced degradation in stiffness, strength, and creep rate when compared to SAC105, even though it has lower silver content. In addition, the doped SAC-X alloy has been observed to reach a stabilized microstructure more rapidly when aged. Mathematical models for the observed aging variations have been established so that the variation of the stress-strain and creep properties can be predicted as a function of aging time and aging temperature.

scholarly journals Dependence of Tin Whisker Growth on Copper and Oxygen Content on the Surface of Tin-Rich Lead Free Alloys

2013 ◽  
Vol 123 (2) ◽  
pp. 430-431 ◽  
Author(s):  
A. Skwarek ◽  
K. Witek ◽  
M. Pluska ◽  
A. Czerwinski
Keyword(s):  
Oxygen Content ◽  
Whisker Growth ◽  
Lead Free ◽  
Tin Whisker
Sign in / Sign up

Export Citation Format

Share Document