Tin Whiskers, Part 4: Causes and Contributing Factors


Reading time ( words)

In this installment of the tin whisker series, we'll take a look at causes and factors that have been found or are considered to contribute to the appearance of tin whiskers. In the remaining installments, we will address “Tin Whiskers - Plausible Theory,” “Tin Whiskers - Impact of Testing Conditions,” and “Tin Whiskers - Preventive and Mitigating Measures.”   

As all-encompassing tests to confirm or deny the culprits that cause tin whiskers are prohibitively costly and time-consuming, my thoughts focus on the logical causes and contributors. Fundamentally, the tin whisker follows the basic physical metallurgy in its principles on nucleation and crystal growth through the classic theories of dislocation dynamics and of other lattice defects in tin crystal structure. Thus, for whiskers to appear from the tin-plated (or tin-coated) surface, the causes and contributing factors should be intimately related to the nucleation sites creation and the subsequent growth paths after the coating process. However, for tin whisker due to tin’s intrinsic characteristics, the actual processes of nucleation and grain growth are dauntingly complex.

Nucleation and growth can be encouraged by stresses introduced during and after the plating process. The sources of these stresses come from multi-fronts. This includes residual stresses caused by electroplating and/or additional stresses imposed after plating, and/or the induced stresses by foreign elements, and/or thermally-induced stresses. Specific causes and contributing factors are outlined below.

Read the full column here.


Editor's Note: This column originally appeared in the March 2014 issue of SMT Magazine.

Share




Suggested Items

KIC Adds Wave Monitoring Technology to Industry 4.0 Ecosystem for Thermal Processes

04/13/2022 | Andy Shaughnessy, I-Connect007
At the SMTA Dallas Expo, Andy Shaughnessy sat down with Miles Moreau of KIC to discuss the company’s latest offering in wave process inspection technology. Miles also explains how KIC’s early focus on automated real-time process monitoring has enabled them to become a leader in Smart factory implementation.

How to Minimize Quoting Time and Increase Accuracy in EMS Production

03/30/2022 | Mark Laing, Siemens Digital Industries Software
New product introductions (NPIs) and customization have been increasing rapidly over the past few years—with the results that the already-small profit margins in electronics assembly are shrinking even further. Fifteen years ago, the PCB was the product. Today, most products are a system, with multiple PCBs, cables, and enclosures. Many manufacturers want to provide turn-key products that have multiple BOMs, making the assembly process even more complicated.

ProMetrics: An Easy, Smart Solution

01/05/2022 | I-Connect007 Editorial Team
Rehm's Michael Hanke speaks about the product on process and the advantages of live process monitoring with ProMetrics, Rehm’s newest monitoring tool, which is brand new and unique in the market. Users say that it’s easy to use and, more importantly, that it provides the security in a system they are looking for.



Copyright © 2022 I-Connect007. All rights reserved.