Inspection of Lead-Free Solder for Tin Whiskers Using the Phenom SEM

By AZoNano Staff Writers

Table of Content

Introduction
Tin Whisker Inspection with Phenom
About Phenom-World

Introduction

In most countries, the use of heavy metals such as cadmium, lead and mercury in electronics is now banned. This has had a major impact on the semiconductor industry. By banning these potentially harmful elements, wich pose health risks and environmental hazards, there is a new problem that may cost manufacturers billions.

Removing lead from the solder in electronic devices can increase the occurence of tin whiskers - crystalline structures which grow due to residual stress on the surface of semiconductor packaging leads. This causes a potential source of arcing and electrical shorting in chips.

Tin Whisker Inspection with Phenom

Tin whiskers have been found to cause complete system failures in cell phones, computers, satellites and missiles. According to analysts these issues have become very common in this new solder-free semiconductor era. This article shows how to detect whiskers easily using the Phenom desktop SEM.

The Phenom offers an excellent tool for inspecting semiconductors for tin whiskers. As it can be easily navigated, the whiskers can be easily located and the online measurement tool makes it possible to measure these whiskers on the spot.

  • First, place a semiconductor chip on a SEM pin mount. Samples can be mounted top down, in cross section, or on a 45° mount. Once the sample has been mounted and loaded into the machine, navigate to a packaging lead using the optical overview window as shown in Figure 1.

Figure 1. Phenom optical Image of two semiconductor packages. The optical overview allows the user to quickly and easily navigate around the package

  • Browse around the packaging lead for any unusual looking structures protruding from the surface as shown in Figure 2.

Figure 2. Low magnification (250x) SEM image shows unusual structures sticking out of from the packaging lead. These structures are indeed tin whiskers and potential sources of arching in the operational product

  • Higher magnification Phenom images can give accurate tin whisker size data as seen in Figure 3.

Figure 3. The Phenom's online measurement function has been used to measure the height of this whisker at approximately 38.79µm

Figure 4. Tin whisker at 3,800x magnification

About Phenom-World

Phenom™, world’s fastest Desktop Scanning Electron Microscope takes your imaging performance to a higher level. The Phenom desktop scanning electron microscope (SEM) helps customers stay competitive in a world where critical dimensions are continuously getting smaller.

The Phenom desktop SEM combines superb imaging power up to 100,000x and outstanding technical performance with better depth of focus and chemical contrast. It is the smart, affordable and market’s fastest solution that enables engineers, technicians, researchers and educational professionals to investigate micron and submicron structures.

With the Phenom proX we offer integrated, powerful EDS microanalysis to complete the optical performance of our SEM-range. Any Phenom system can be tailored to suit application and sample needs by choosing one of the many Pro Suite-based software solutions or specially designed hardware accessories.

Phenom-World helps you to stay competitive in a world where critical dimensions are continuously getting smaller. The Phenom desktop SEM offers direct access to the high-resolution and high-quality imaging necessary in a large variety of applications. It is an affordable solution that enables engineers, technicians, researchers and educational professionals to visualize micron and submicron structures.

This information has been sourced, reviewed and adapted from materials provided by Phenom-World BV.

For more information on this source, please visit Phenom-World BV.

Date Added: Feb 21, 2014 | Updated: Mar 7, 2014
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