Transcript Slide 1

DMSMS
Kissimmee, Florida
December 2nd – 5th, 2013
Use of Plastic Encapsulated Microcircuits (PEMs) in
Military and Space Systems: A review of 15 years of
actual PEM reliability data.
Joseph L. Holt
Vice President Business Development
Integra Technologies LLC
3450 N Rock Road Building 100
Wichita, Kansas 67226
Ph 316-630-6808
Email: [email protected]
Web: www.integra-tech.com
How Can PEMs Increase Material Availability?
How can use of Plastic Encapsulated Microcircuits (PEMs) reduce
diminishing material availability issues and add flexibility to parts
management challenges?
• The short answer is that because inexpensive consumer electronics
drive todays semiconductor manufacturers, inexpensive plastic
parts are by far the dominant package type – which means suppliers
are more likely to support these technologies for a longer period of
time.
• It does not mean they will support plastic devices as long as many
Aerospace and Defense contractors need, but all other things being
equal, plastic parts will likely be available longer than hermetic.
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Other (Better) Reasons to use PEMs
• Other reasons to use PEMs in addition to greater availability:
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Generally lower cost materials
Greater investment in supplier product improvement programs
Greater product variety
Mechanically more rugged
Lighter weight
Available in smaller/thinner packages
More automated assembly methods
Higher volume/more cost effective production
Increasing reliability due to supplier competition
• All of the above items will help reduce end system costs. And with
the relentless pressure to reduce costs (sequestration, budget
deficits, congressional gridlock, recessions in US and Europe, etc.)
the ability to reduce costs are at least on par with availability as a
reason to use PEMs and arguably even more important.
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So why bother with a PEM Qual
If PEMs are so good, why bother qualifying them at all?
• PEMs have predominately been designed for commercial and
industrial applications – not Aerospace and Defense (A&D).
• Higher military temperature ranges are not generally available.
• Screening and qualification testing by the semiconductor
suppliers are not always as stringent as A&D end applications
require.
• Reliability of plastic packages varies dramatically from supplier
to supplier
Any of these reasons should be justification by themselves to perform
PEM Quals, but the last reason makes it essential to intelligently
evaluate the use of plastic parts. There is a substantial variation from
supplier to supplier in PEMs reliability, as our data will show.
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What is a PEM Qual
Example PEM Qual flow (per NASA PEM-INST-001):
• External Visual and Serialization: Qty=32
• Baseline CSAM: Qty: 32
• Pre-Conditioning: Qty=32
• Moisture Soak per appropriate MSL Level
• Reflow at 235C
• Electrical Testing at 25C, min and max operating temp; Qty=32
• Sub-Group 1 Qual: Qty=22
• 125C Life Test for 1000 hours
• Electrical Testing at 25C, min and max operating temp
• Temp Cycle; 200 cycles
• Electrical Testing at 25C, min and max operating temp
• CSAM; 22 units
• DPA : 5 units (per sec.5.3/ Fig 4 of PEM-INST-001 spec)
• Subgroup 2 Qual: Qty=10
• Unbiased HAST; 96 hours at 130C/85%RH
• Electrical Testing at 25C, min and max operating temp
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What is a PEM Qual
PEM Qual flow notes:
• Most customers customize PEM Qual flows to be more stringent or less
stringent depending upon their application needs.
• This is important because over qualifying adds evaluation cost while
eliminating devices that might otherwise be reliable enough and lower
priced.
• Even worse, under qualifying may lead to inadequate device reliability and
system field failures.
• Clearly understand how comprehensive the electrical test coverage is that
your test supplier is providing. Insufficient electrical test coverage will
allow failing devices to be counted as passing and could lead to poor
system and field reliability.
• Thorough and intelligent assessment of the intended application is
essential for the successful use of PEM devices.
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What are the Typical PEM Qual Failure Types
Typical PEM Qual Failure Types:
1. Cracked Die
2. Wire breaks
3. Wire Lift
4. Delamination
5. Corrosion
6. Contamination
7. Moisture Ingress
8. Cracked Package
9. Cracked Passivation
10. Die Attach Voids
• Most PEM Quals start by assessing the die level qualification data already
available from the manufacturer. Once the die level reliability data is
deemed acceptable, the PEM qual can evaluate the package versus the
application needs.
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Integra PEM Qual Data Overview
Time Period Covered: 1998 through August of 2013
Total Number of Parts Processed: 111,183
Total Number of Lots:
791
Total Number of Passing Lots:
496
Passing Lot Percentage:
63%
Total Number of Failing Lots:
295
Failing Lot Percentage:
37%
Total Customer Part Numbers:
455
Total Manufacturer Part Numbers:
410
Total Number of Manufacturers:
73
Total Number of Customers:
42
Unique Pin/Package Combinations:
165
Notes:
• No qualifications conducted by semiconductor manufacturers are included.
• Plastic packaged semiconductor devices only - no passives.
• Predominant test temperatures are -40, 25 85 and -55, 25 125.
• Testing temperature order is usually room, cold, hot.
• Once a qual fails it is usually stopped.
• Failures are for electric test only (no mechanical failures).
• Vast majority of testing performed to manufacturers datasheet limits.
• Virtually all electrical test programs written by Integra Technologies.
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Overall PEM Pass/Fail Rate
This data suggests that PEMs are getting more reliable over time or that
the customers are getting smarter about which suppliers to select for
PEM quals. We actually believe it to be both.
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Overall Customer PEM Qual Success Rate
Average Pass Rate = 80%
Customers who are more
experienced with PEM Quals
tend to have better success.
These 4 customers averaged
over 100 PEM Qual lots each
over the 15 year analysis period.
The average pass rate over the
entire population is 63%.
Average Pass Rate = 42%
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Customers who are less
experienced with PEM Quals
tend to have less success.
These 4 customers averaged ~4
PEM Qual lots each over the 15
year analysis period.
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Overall PEM Qual Success Rate by Package
There are meaningful differences between
package types in their ability to pass a PEM Qual.
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Overall PEM Qual Success Rate by Package Pin Count
Despite the sensitivity to package type shown on
the previous page, there does not appear to be a
meaningful sensitivity to package pin count.
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Overall PEM Qual Success Rate by Device Technology
There is not a great deal of sensitivity to
technology, with the exception of memory. It
should be noted that the memory devices we
evaluated tended to more often come in packages
that were previously shown to be less reliable.
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Overall PEM Qual Success Rate by Device Technology by Supplier
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Overall PEM Qual Success Rate by Device Technology by Supplier
Many suppliers have good
PEM Qual results….
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Overall PEM Qual Success Rate by Device Technology by Supplier
Many suppliers have good
PEM Qual results….
…But many suppliers do not.
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Overall PEM Qual Success Rate by Device Technology by Supplier
Many suppliers have good
PEM Qual results….
Acceptable
suppliers can be
found for most
technologies.
…But many suppliers do not.
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Overall PEM Qual Success Rate by Supplier
This is arguably the most important point of this
data analysis – that PEM Qual success rates vary
dramatically from supplier to supplier.
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Overall PEM Qual Conclusions
1.
There is a great variation in the success rate depending upon
the supplier that is being evaluated, so it is prudent to evaluate
multiple suppliers.
2.
Success rate is also influenced by the package being
evaluated, although not to as great an extent as by the supplier.
3.
Acceptable PEM Qual success rates can be obtained with most
technologies and pin counts.
4.
Understanding your application needs is essential for selecting
the best PEM Qual flow. By matching the PEM Qual flow to the
application needs, an accurate assessment can be made at the
lowest evaluation cost.
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Overall PEM Qual Conclusions (continued)
5.
Clearly understand how comprehensive the electrical test
coverage is that your test supplier is providing. Insufficient
electrical test coverage will allow failing devices to be counted
as passing and could lead to poor system and field reliability.
6.
PEM Quals are very complex flows with hundreds of processing
steps and thousands of data points. Assure that trained project
management staff is present at your test supplier to manage
the flow execution and assure data integrity.
7.
Overall, PEM Quals can be used to effectively select devices for
use in non-commercial environments. In this study,
approximately two-thirds of industry devices will pass PEM
Qualification.
8.
These conclusions are consistent with the conclusions reached
in 1998 when we last analyzed our database, although our data
indicates that PEM Qual success rates are improving.
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Upscreening – The Simplest Form of PEM Qual
• Upscreening is where a device is not subjected to any
environmental testing (Temp Cycle, HAST, etc.), only to
electrical testing at temperatures beyond where the original
manufacturer tested.
• Upscreening is the simplest form of a PEM Qual even though
it is not technically a “qualification.”
• Many customers combine upscreening and PEM qualification
when assessing the suitability of a device for given
application.
• Integra also has considerable upscreening data.
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Integra Technologies Historical Upscreening Data
Overall Summary of Upscreening Data
Time period data taken
# of electrical test steps*
# of devices tested
# manufacturer part numbers
# manufacturers
# of customers
Overall failure rate
Minimum failure rate
Maximum failure rate
13 years (1999-2012)
19,489
11,678,154
1,403
14
176
0.93%
0.00%
100%
* A test step is group of customer devices tested at a
given temperature. The same devices are typically
tested again at a different temperature. These are
separate “test steps”.
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Upscreening Data by Supplier
Supplier failure rates vary significantly from supplier to
supplier.
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Upscreening Data by Test Temp by Technology
Some technologies show better performance than others
at extended temperature ranges.
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Upscreening Data by Pin Count
Device failure rates tend to be higher for higher pin count
devices.
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Upscreening Data by Package
Device failure rates vary meaningfully by package type.
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Upscreening Data by Year
An initial look at
the data would
seem to indicate
that device failure
rates are going
up……
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Upscreening Data – Lots Tested & # Zero Fail Lots
The number of
lots tested is
going down….
As customers
eliminate devices
that do not fail.
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Upscreening Data by # Failing Devices
But the actual
number of gross
failing devices is
actually increasing
slightly.
Conclusion – Customers are becoming more
adept at upscreening only those devices that
really need it, but many devices continue to
need to be screened – the trick is to know
which ones.
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Upscreening Data Conclusions
Upscreening Conclusions
1. Customers are reducing testing when data shows that no failures
are being found.
2. While the number of lots being tested is going down, the number of
gross failing devices is staying constant and even increasing. This
suggests that certain devices definitely still need to be screened,
but others may not require screening or can go to sample testing.
3. Failure rates still vary significantly by supplier and by technology.
4. Clearly understand how comprehensive the electrical test coverage
is that your test supplier is providing. Insufficient electrical test
coverage will allow failing devices to be counted as passing and
could lead to poor system and field quality/reliability.
5. Upscreening can be successfully used to yield devices that can
perform at extended temperature ranges.
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Upscreening Data Notes
Important Notes for Upscreening Data
1.
The data only contains information for devices tested for users of integrated circuits (IC’s). No
test results are included for devices tested for an original semiconductor manufacturer.
2.
No test results are included for custom fabricated devices manufactured exclusively for a specific
end user.
3.
The failure rates in the data tables should be considered minimum failure rates because if testing
of a device reveals high fallout, it is usually designed out (or an alternate part is selected by the
customer) therefore eliminating the highest failing devices from the tested population. In
addition, many customers characterize smaller samples at the system level prior to upscreening
so they can determine if the yields will be acceptable.
4.
The vast majority of the lots were tested at one of the following temperatures: +125C, +85oC,
25C, -40oC & -55oC.
5.
The vast majority of the tests performed were to the original manufacturers data sheet.
6.
The vast majority of the test software used was developed independently by Integra, without
help from the original manufacturer.
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Upscreening Data Notes
Important Notes for Upscreening Data
7.
~97% of the lots tested were for Military and Avionics customers.
8.
No lots designated as Counterfeit were included, as electrical testing is often very
abbreviated.
9.
The failures noted are for electrical failures only. No mechanical failure information is included.
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Integra Technologies Thanks You
Thank you from the Employee
Owners of Integra Technologies!!
Integra Technologies LLC, along with the recently acquired Analytical Solutions, has been
providing one of the broadest ranges of test and evaluation services in our industry for over
30 years. Our services include:
Test Development
Final Test
Characterization
Wafer Probe
Upscreening
Failure Analysis
Counterfeit Detection
PEM Qualifications
Qualification Services (HTOL, HAST, Temp Cycle, etc.)
Assembly/Repackaging (outsourced to qualified partners)
MIL-STD 883 and 750 Testing
Volume Production Test
Destructive Physical Analysis
Obsolescence Management
We are approved by DLA for MIL-STD-883 & 750 processing, ITAR, ISO 9001, AS9100
and DMEA Category 1 “Trusted”
www.Integra-Tech.com
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