Challenges in Integrated Electronic System Designs
1. Challenges in Integrated Electronic System Design
Manasa.K
CWB0912002, FT-2012
M. Sc. (Engg.) in Electronic System Design
Engineering
Module leader: Mr. Ugra Mohan Roy
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3. Introduction
• The increasing complexity of electronic components and the need for
portable low-power gadgets that can operate in stressful environments make
the design more challenging.
• The physical phenomena at submicron feature dimensions are having more
and more impact, not only on performance, but even on the functionality.
• Common examples include communication devices such as cell-phones and
personal digital assistants (so-called PDA's), aircraft flight controls,
autonomous vehicles, sophisticated weapon systems and tiny medical
devices inside or outside of the human body, such as heart monitors etc.
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4. 1. Electrical Over-Stress (EOS)
• EOS describes the thermal damage that may occur when an electronic device is
subjected to a current or voltage that is beyond the specification limits of the device.
• EOS damage occurs because of the direct and indirect effects.
• Thermal damage is the result of the excessive heat generated during the EOS
Event.
• The high currents during the EOS event can generate very high temperatures even
in the normally low resistance paths.
• An EOS event can last only for milliseconds or can last as long as the conditions
persist.
•EOS damages occurs both internally and externally in a system.
EOS external damage
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5. Electrical Over-Stress (EOS)
EOS internal damage
Causes for EOS:
• Uncontrolled voltage surge on the power supply
• Overshoot or undershoot during IO switching
• ESD events that trigger a larger EOS event or
cause damage that weaken the device making it
more susceptible to future EOS events.
• Voltage spikes due to internal PCB switching.
• Latch-up events may result in EOS damage if the
current is high or if it persists for an extended time
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Melted Bond Wire
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6. 2. Packaging
Packaging is the barrier between electronic parts and the environment, it is very
susceptible to environmental factors.
• Material fatigue from the thermal expansion caused by heating cycles.
• Mechanical stress and shock can crack or fracture packaging.
• Humidity and chemicals can cause corrosion.
• Material defects introduced during manufacturing and processing.
• Electrical faults introduced during encapsulation (bonding wire short and open
circuits).
• Migration of contaminants through the packaging onto the semiconductor die
Corrosion with moisture
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7. 3. Printed Circuit Board
Today PCBs have evolved from 100% through-hole, 100-mil technology to a
mixture of through-hole and surface mount processes involving thousands of
components.
Double-sided boards have evolved into multi-layer boards with 5 and 6 layers can
go upto14 layers. As the complexity of the PCB manufacturing process has
increased, the possibility of process defects has also increased.
The causes for failure for a PCB are,
• Residues of solder flux may facilitate corrosion.
• The traces may crack under mechanical loads and may result in unreliable PCB
operation.
• Via cracking during soldering
Flux residue between the connector nodes
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cracked solder joints
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8. 4. Electrostatic Discharge (ESD)
Electrostatic Discharge (ESD) can damage a sensitive electronic component,
resulting in failures, reduced reliability and increased rework costs, or latent
component failures.
ESD damages are generally classified as either a catastrophic failure or a latent
defect.
Catastrophic failure: The device's circuitry is permanently damaged causing the
device to stop functioning. Such failures usually can be detected when the device
is tested before shipment.
Latent failure: A latent defect, is more difficult to identify. A device that is
exposed to an ESD event may be partially degraded, yet continue to perform its
intended function. However, the operating life of the device may be reduced
significantly. This failures are usually costly to repair.
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9. ESD can cause hardware damage in the following electronic systems:
• Melting of metallization traces due to high levels of thermal overstress that
EOS induces.
• Intense electric fields that can cause interference or failure of nearby
electronics.
• Component degradation or latent defects in device structures that don't lead to
immediate failure but cause intermittent malfunctioning and field failures after
exposure to stress.
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10. Summary
• The challenges in integrating electronic system design is increasing due to the
complexity of the system and also because of the decrease in size of the
components to submicron level.
• Electrical Over-Stress is one of the challenge which effects the system both
internally and externally because of the high temperatures.
• Packaging is the barrier between the electronic parts and the environment, this
causes cracks in the packaging when mechanical stress is applied, corrosion is
caused due to the humidity and reaction of chemicals.
• Via cracking during soldering, residues of solder flux etc are some of the
causes for failures in the printed circuit boards.
• The two types of ESD damages are, catastrophic failure and latent defect.
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11. References
•
An Introduction to ESD (2010) Fundamentals of Electrostatic Discharge ESD
Association, Rome, NY (2nd August 2013)
•
Jacob A. Abraham Formal Verification Techniques and Tools for Complex
Designs University of Texas at Austin (2nd August 2013)
• V Lakshminarayanan (2000) Minimizing failures in electronic systems by
design Centre for Development of Telematics ( 3rd August 2013)
• Code 560 Handbook Parts, Packaging, and Assembly Technologies Office
Electrical Engineering Division, NASA GSFC Greenbelt, Maryland (3rd
August 2013)
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