7-
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SECTION 7
TESTING INTEGRATED CIRCUITS
7-1. Integrated Circuits
Digital integrated circuit (IC) chips are made from transistors on a common substrate. Their
Tracker signatures are typically variations of the discrete diode and transistor signatures. Most
logic ICs contain multiple circuits on one chip. These chips can have pins from 8 to over 200,
although quite often many pins share quite similar signatures. This can make troubleshooting
easier by giving us an easy-to-find signature to use as a comparison. In this section, it is
important to understand how the Tracker 2700 and TSA respond to these circuits.
Integrated Circuit Failures
A functioning IC may stop working for a number of reasons. Some of the most common causes
of IC failures are:
• EOS: Electrical Over Stress. The IC’s maximum electrical specifications have been
exceeded. This condition may result in the IC developing internal shorts and opens.
• ESD: Electrostatic Discharge. Repeated exposure may cause internal resistance to develop
in the IC junctions. This internal resistance may vary from 5 kΩ to 25 kΩ with a typical value of
20 kΩ. ESD exposure can cause internal flaws such as resistance, opens and shorts.
• Dendrites: A process flaw that results in particles growing between conductors on a substrate
causing shorts.
• Ionic Contamination: Contamination introduced at the time of manufacturing that develops into
leakage between substrate channels. This causes 5 kΩ to 25 kΩ of resistance.
• Purple Plague: Destructive interaction between gold and aluminum metal layers. Junction
connections become very brittle and may cause internal opens.
• Corrosion or Another process flaw in which aluminum metalization causes Electromigration
pinholes, corrosion and resistance. This will create opens and resistance.
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