The Biggest Impact on the
The Phenom Provides Excellent Tool
for Inspection of Tin Whiskers
The Phenom is a new tabletop scanning electron microscope (SEM)
which combines the high magnification of electron microscopy with the ease of
use of optical microscopy to improve performance in a tabletop instrument.
The Phenom, a tabletop SEM provides useful magnifications up to
20,000x, is easy to use as the typical laboratory-grade optical microscopes. The
cuts away the time, difficulty, and expense of the conventional SEM. The
operator simply places the sample in the specially designed holder on the
microscope. Due to its unique design there is no risk of damaging the lens. The
automatically focused image is displayed in less than 30 seconds later, with the
resolution and depth of focus typical belonging to SEMs.
Figure 1. Phenom Desktop SEM
The Biggest Impact on the Semiconductor Industry
Recent legislation by many countries has banned the use of heavy metals such
as lead, cadmium, and mercury. The biggest impact has been on the semiconductor
industry. While the removal of these potentially harmful elements will eliminate
potential health risks and environmental hazards, it also poses a new problem
that could cost manufacturers billions.
The removal of the lead from the solder of semiconductor devices can cause
and expedite the growth of tin whiskers. When lead is not mixed into the alloy,
residual stress on the surface of semiconductor packaging leads can cause the
growth of these crystalline structures. This creates a potential source of
electrical shorting and arching in chips. Tin whiskers have caused total system
failures in computers, cell phones, missiles, and satellites. Analysts predict
that these issues will become more frequent in this new solder-free
semiconductor era. This note has been created to illustrate how to easily detect
tin whiskers using the FEI Phenom.
The Phenom Provides Excellent Tool for Inspection of Tin Whiskers
The Phenom provides an excellent tool for the inspection of
semiconductors for tin whiskers. It's simple to use navigation makes it easy to
locate these tin whiskers 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 degree mount. Once the sample has been
mounted and loaded into the machine, navigate to a packaging lead using the
optical overview window (Figure 2).
Figure 2. 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 (Figure 3).
Figure 3. Low magnification (250x) SE M 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
Higher magnification Phenom images can give accurate tin whisker size data as
seen in Figure 4.
Figure 4. Tin whisker at 3,800x magnification. The
Phenom's online measurement function has been used to measure the height of this
whisker at approximately 38.79µm.
Figure 5. Tin whiskers at 3,750 x magnification.
Source: "Tin Whisker Inspection with Phenom" Application Note
For more information on this source please visit Phenom-World