Evaluation Engineering - 14

BURN-IN TEST

Joe Gorley, product manager for DMMs
and switching at Tektronix: "For this type
of testing, engineers want as much measurement capability and test capacity as
they can get from individual instruments
so that the same instrumentation can be
used in many types of test systems. As
well as flexibility, test engineers need
more speed to reduce test times and test
costs. They also want ease of use and fast
intuitive set up."

Challenges
What key challenges are burn-in test
solution vendors or their partners facing
today?
Rogers, Aehr Test Systems: "The traditional semiconductor industry faces the challenges of cost and increasing technology
requirements. Heterogenous (previously
MCM) packaging technology is enjoying a
large re-emergence driven by the limits of
shrinking CMOS process technology, and
the use of new compound-semiconductor
process materials combined into modules
are achieving much lower yields after
the burn-in process. Production burn-in
times of 12 to 24 hours are now extending
to days before the fault surfaces-driving
the overall production and scrap material
cost up significantly. To reduce the scrap
module material while reducing the production costs, wafer-level burn-in is being utilized more extensively by enabling
thousands of devices to be burned-in in
parallel and detecting device faults before
integration into the module."
Booher, TotalTemp Technologies: "[We address challenges through] better automation features, such as cascade temperature control for optimum achievement of
temperature set point, along with alarm
features that can alert test operators by
text or email when a test is complete, before damage is done or time is wasted."
Hsu, Preen AC Power Corp.: "For burn-in
testing, most applications do not require
very sophisticated features on the power
source. The main requirement is to simulate the AC power (adjustable voltage and
frequency) or DC power to feed into the
UUT. If using high-end programmable

14

EVALUATION ENGINEERING NOVEMBER 2019

power supplies, the cost will be too high,
and the total kVA may require certain
quantity of supplies to be connected together in parallel. If a customer is using a
variable transformer, there is no regulation on the voltage and no flexibility to
change the frequency. The market needs
something in between."
Gorley, Tektronix: "An ongoing challenge
is to find ways to increase measurement
speeds and reduce test times while also
improving accuracy and versatility.
Another challenge is the need to enhance communication and control capabilities, which can help to reduce test
times. Instruments must also be able to
accommodate multiple interface options,
such as USB, Ethernet, or GPIB. And no
one likes downtime, so there's constant
pressure to widen calibration intervals.
Additionally, the industry is moving
away from electromechanical relays and
adopting solid-state switch modules that
provide much longer life spans and other
benefits."

What are customers asking for?
What key features or attributes are
customers asking for in burn-in test
solutions?
Rogers, Aehr Test Systems: "Customers
are asking for massively parallel testing
with individual die supplies, and they are
asking for the monitoring of voltage, current, and thermal properties in real-time
during the burn-in process."
Booher, TotalTemp Technologies:
"Customers are all about efficiency, and
custom test solutions often result in a
much more effective test than a cheap
off-the-shelf solution."
Eric Turner, general manager, E-A
Elektro-Automatik USA: "For power
supply testing, customers are asking
for energy-saving techniques, including
high-efficiency programmable sources
and regenerative loads."
Hsu, Preen AC Power Corp.: "Customers
are looking for high efficiency, high power,
adjustable voltage and frequency for AC

supplies, adjustable voltage and current for DC supplies, and bidirectional
operation."
Gorley, Tektronix: "More intuitive test set
up-As existing test equipment becomes
obsolete, new models need to be straightforward to use, helping long-time users of
the replaced equipment quickly come up
to speed on the new tools. Compatibility-
While equipment vendors are quick to put
in new and better features, test standards
change more slowly. Not only will an operator look for similar user controls, they
will look for common remote programming commands. Additionally, they are
looking for similar hardware options or
accessories. Other features customers
want include a greater number of on-instrument saved setup options to promote
quick recall of standard test configuration
settings; greater speed of test set-up on
a statistically significant number of devices; greater ease in connectivity and/or
remote monitoring of test status while the
test is in progress; and a comprehensive
options for graphical or tabular display
of data on instrument or via software."

Now on the market
What burn-in test solutions have vendors
introduced recently, and what are their
key features?
Rogers, Aehr Test Systems: "We introduced in early 2019 two new models in
our FOX family of wafer-level systems to
complement our FOX-XP production system, which can burn-in up to 18 wafers
at a time. The FOX-NP was introduced
in January 2019 as a low-cost entry-level
system to provide a configuration and
price point for companies performing
initial production qualification and new
product introduction. This enables an
easy transition to the FOX-XP system
for high-volume production burn-in test.
The FOX-CP was introduced in February
2019 and is a new low-cost single-wafer
compact test and reliability verification
solution for logic, memory, and photonic
devices where test times range from
minutes to a few hours or where multiple
touchdowns are required to test the entire
wafer. It complements the capabilities of
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