Transcript 2001CTMA DAY - National Center for Manufacturing Sciences

Static Event Health Monitoring
A Capability Improvement Program
Tom Odom
VCD Technologies
San Dimas, California
National Center for Manufacturing Sciences – Commercial Technologies for Maintenance Activities
16-18 April 2002
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Topics
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History of the Technology
Magneto-Optics
Prototype ExMOD Detectors
Detector Fabrication
Proposed Technology Improvements
Risk Analysis & Mitigation
Conclusions
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History of the technology
- Bubble Memories
- Developed in the 1970’s as an alternative to magnetic tape
data storage
- Photo lithographically defined magnetic domains on a single
crystal wafer.
- Used Large Scale Integration processes developed for the
semiconductor industry
- Light Modulation Devices
- Developed for Military applications in the 1980’s.
- Used Single Crystal Magneto-Optic wafers to modulate light in
nano-second time frames.
- Missile tracking applications
- Image Projection
- Magneto-Optic Static Event Detectors (MOSED)
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History of the technology, (continued)
Switched pixel
- Magneto-Optic Static Event Detectors
(MOSED)
- Invented and demonstrated in 1990’s
- Created to aid in the detection of ESD
events.
- Magnetic fields created by the ESD
transient changes the properties of the
Magneto-Optic thin film deposited on a
single crystal substrate
- Devices can be remotely reset
- Effect is observed using a polarizing
microscope
Un-Switched pixel
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Magneto-Optics
 Magneto-Optic Effects
- Kerr Effect for Magneto-Optic Recording
- Faraday Effect for Light Modulation and memory
devices
- Also known as the Magneto-Optic Effect, was the
first experimental evidence that light and magnetism
are related
- Result of ferromagnetic resonance in association
with a magnetic field
- Resonance causes waves to be decomposed into
circularly polarized rays which propagate at different
speeds (circular birefringence)
- Upon re-combining, owing to the differences in
propagation speed, a net phase offset and a
resulting rotation of the angle of linear polarization
results.
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Magneto-Optics, (continued)
 A magnetic field, caused
by ESD transient, Changes
the way light is polarized
in the M-O Material
 Polarization changes are
permanent until device is
externally reset
 Effect is observed using a
polarizing microscope
UNPOLARIZED LIGHT
VERTICAL
POLARIZER
HORIZONTAL
POLARIZER
PLANES OF POLARIZATION ROTATED
FIG. 3 – DETAILS OF MAGNETO-OPTIC ESD
DEVICE FUNCTION
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Prototype ExMOD Detectors
TO-5 packaged Detector
 Manufactured
from Prototype
Magneto-Optic
wafers
 Uses mature
Semiconductor
wafer
processing
techniques and
materials
0.030
Over 6000 die can be
produced from a 3
inch diameter wafer
3.00
0.020
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Detector Fabrication
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M-O Thin film is grown over non magnetic substrate wafer
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Wafer is patterned and etched in the sequences shown below
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M-O devices are characterized and tested to determine electro-optic performance
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Prototype Detectors
Advantages of the old Technology
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Resettable: The device can be reset as many times as desired so long as the current
remains below protection level.
Static Memory: The device remains permanently switched after an ESD event until
reset. Alternatively, the device can be observed continuously to record the time and
threshold of the event.
Small Size: The die can be as small as 500mm x 750mm.
External Readout: The device can be read without physical contact, using a polarizing
microscope/optical system.
External Reset: The sensing device can be reset with an external non-contact device.
Solid State: Operates at extreme temperatures and environments.
Fast Switching: Provides discharge detection of fast ESD pulses generated by HBM,
CDM, and MM events.
Polarity Sensitivity: If required, the device can distinguish the polarity of the ESD
event.
Sensitivity Levels: High or low threshold devices will be available.
Pulse Resolution: Current devices can detect ESD events down to 300mA.
Custom Configuration: Available for customer specific applications with associated
engineering development.
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Prototype Detectors
Disadvantages of the old Technology
 Difficult to view
- Expensive microscopes are
required to view the event
- Dual Polarizer analyzers
required
 Difficult for customer to
Assemble
 High Cost of Fabrication
at low volume
 Customer acceptance of
new technology
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Proposed Technology Improvements
for CTMA / NCMS Cost share
 Detector Device
Improvements
- Replace multi-domain
detector (14 individual
sensors) with a single,
active, domain
- Add a redundant
domain for Readout
verification
Increase domain size to
increase readout signal
strength and
simplification
Active Domain
Redundant domain
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Proposed Technology Improvements
for CTMA / NCMS Cost share
Alternative Two Cell Structure to discriminate polarity
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Proposed Technology Improvements
for CTMA / NCMS Cost share
Readout Reset Device Improvements
Replace the polarizing microscope with an autonomous reader.
The new reader will consist of the following components & subsystems
- Polarized light source
- Magnifier
- Charge coupled device (CCD) camera or other sensing device
- Optical elements that cross polarize incoming and reflected light
- Processor
- Result indicator
To read the MOSED, a Reader is placed above and in proximity to the MOSED to determine its state of polarization
To reset the device , a permanent or electro-magnet device is integrated with the readout device
Example of Readout
Device concept
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Proposed Technology Improvements
for CTMA / NCMS Cost share
Operational Scenario
Step
Action
1
The suspect circuit board is placed under the
Reader such that the MOSED device is within the
field-of-view
The Readers computer triggers a light source and
the corner cube at the back side of the MOSED
reflects the light back onto the Readers CCD
The position of the two magneto-optic pixels are
determined
The polarizer is rotated to null the signal from the
inert pixel
The signal from the active pixel is compared to the
signal from the inert pixel.
Signal differences greater than a specific
threshold indicate that the magnetic state of the
device has changed and therefore a potentially
damaging ESD event has occurred
A green (no event) or red (event occurred) light
system can be used to indicate the ESD event
status
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Risk Analysis & Mitigation
 Multiple Deliveries
- MOSED Device in discrete package
- Static Sensitive Test devices integrated with the new SED to
characterize performance
- Multiple threshold devices for wide range of ESD sensitive
devices
 Diverse Applications
- Surge Suppression device will be co-developed
- Use state-of-the-art surge suppression technology
- Couple with MOSED to identify existence of surge
 Government Review and Concurrence
throughout development cycle
- Multiple workshops to obtain government input
- Reduces risk of redesign to meet user needs
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Conclusions
 Detection of ESD events can benefit the life cycle of
electronic devices
- Manufacturers can improve on processes that historically have
damaged, destroyed or degrade devices.
- End users can improve their handling of ESD sensitive devices,
resulting in improved reliability in the field.
- Depot repair facilities can improve their ability to minimize field
returns thereby providing added value to their repair/replacement
functions.
 The Existing MOSED technology can be improved to
overcome deficiencies in a risk-controlled CTMA cost
share development program
- Provides Government and industry users with cost effective tools
necessary to detect, analyze and control ESD events
- Dual Use technology improvements will result in significant cost
savings for government and industry.
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