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TEMPERATURE CYCLE (T/C)
Temperature Cycle accelerates the effects of thermal expansion mismatch between
different components of the packaging system, a condition which can cause wire bond
problems and seal leakage. Temperature Cycle is typically performed per Mil Std 750 or
Mil Std 883, Method 1010, Condition D.
Devices are inserted into cycling system and held at -65C for at least ten minutes, devices
are then transferred to a second chamber and held at +150C for at least 10 minutes. The
system employs a circulating air environment to assure rapid stabilization at the specified
temperature. The dwell at each extreme, plus two transition times of five minutes each,
constitute one cycle. The duration of this testing is typically 500 or 1000 cycles.
A device shall be considered as a reject, if hermeticity cannot be demonstrated, parametric
limits are exceeded, or if functionality cannot be demonstrated, as per the data sheet
limits. Mechanical damage, such as cracking, chipping, or breaking of package, will also be
considered as a reject provided such damage was not caused by fixturing or handling.
Verified EOS and ESD failures shall not be considered as legitimate rejects.
TEMPERATURE HUMIDITY BIAS (THB)
This is an environmental test performed at a temperature of 85
°
C and a relative humidity
of 85% (per JEDEC Standard 22 Method A101). The test is designed to measure the
moisture resistance of plastic encapsulated circuits. A nominal (5V) static bias is applied
to the device to create the electrolytic cells necessary to accelerate corrosion of the
metallization. Typical stress duration is 1008 hours.
A device will be considered to have failed the static temperature humidity bias test if
parametric limits are exceeded, or functionality cannot be demonstrated under normal and
worst case conditions as specified in the data sheet. Device which recovers after baking
shall be considered as a reject. Verified ESD or EOS failures shall not be considered
legitimate rejects.