MIL- STD-883F 2004 TEST METHOD STANDARD MICROCIRCUITS.pdf - 第133页

MIL-STD-883F METHOD 1020.1 15 November 1991 5 Before t esti ng LSI/VLSI c irc uits , an analys is is of ten requir ed to deter mine li kely l atchup pat hs and requi rements for bias condit ions, exposure st ates, and fu…

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MIL-STD-883F
METHOD 1020.1
15 November 1991
4
2.3.4 Monitoring and recording equipment
. Equipment to monitor and record the parameters required in the test plan or
procedure shall be integrated into the latchup test system. Oscilloscopes and transient digitizers may be used to monitor
the transient response of the device. Additionally, the dose records from each pulse shall be correlated to the specific
device(s) irradiated by that pulse.
2.3.5 Timing control
. An adjustable timing control system shall be incorporated into the latchup test system such that
post-irradiation in-situ functional testing is performed at the specified time, typically 50 µs to 300 µs, after the radiation pulse.
Longer time periods, as long as several minutes, may be required to complete the functional tests for complex devices.
2.3.6 Temperature control
. When testing at other than room temperature, a temperature control system shall control the
temperature of the DUT to ±10°C of the specified temperature. Unless otherwise specified, latchup testing shall be
performed at the highest device operating temperature in the system application or 15°C below the maximum rated
temperature of the device, whichever is less. (See cautionary note below.) If an application temperature is not known, or is
not available, the device shall be tested at 15°C below the maximum rated temperature. Heat sinking may be required to
ensure that the device is not operated above the maximum rated temperature.
CAUTION: The thermal conduction through the latchup test sockets is often much less than that through the pins in
soldered boards.
3. PROCEDURE
.
3.1 Device identification
. In all cases, devices shall be serialized, and the applicable recorded test data shall be traceable
to the individual device.
3.2 Radiation safety
. All personnel shall adhere to the health and safety requirements established by the local radiation
safety officer or health physicist.
3.3 Total dose limit
. Unless otherwise specified, any device exposed to more than 10 percent of its total dose limit shall
be considered to have been destructively tested. The total dose limit shall be determined for each device type to be tested,
and shall be specified in the test plan.
3.4 Characterization testing and analysis
. Characterization tests should be performed on new or unfamiliar device types
to determine their performance as a function of dose rate and to establish requirements for production testing. Because
latchup is dependent on lot to lot variations, samples for characterization tests should be pulled from the production lot(s).
The following are examples of information gained from characterization testing:
a. Latchup threshold as a function of radiation dose, dose rate, and pulse width.
b. Existence and dose rate range of latchup windows. To check for windows, latchup testing is performed over a
wide range of dose rates in fine increments.
c. Worst case or unique conditions that cause the device to exhibit latchup, such as operating voltage, temperature,
and bias conditions.
d. Method(s) to detect latchup, e.g., monitoring supply current, functional testing, or both. Note that in-situ functional
tests must be thorough enough to determine if a small portion of a large circuit has latched without drawing
enough additional current to significantly increase the device supply current.
e. Group A electrical parameter degradation subsequent to latchup testing.
f. Holding current and holding voltage.
MIL-STD-883F
METHOD 1020.1
15 November 1991
5
Before testing LSI/VLSI circuits, an analysis is often required to determine likely latchup paths and requirements for bias
conditions, exposure states, and functional testing. These large circuits often have too many outputs to be monitored
individually, and through the analysis, monitored outputs can be limited to those most apt to show a change should latchup
occur.
3.5 Production testing
. Prior to production testing, characterization testing shall be performed at least once for new or
unfamiliar device types (i.e., new design or process, unfamiliar or very complex devices with little or not latchup test history).
The results of the characterization tests are used to develop the requirements for the production tests (see 3.4). These
requirements are specified in the applicable test plan or procedure and include those items listed in 1.2.
3.5.1 General requirements for production tests
. Unless otherwise specified, the dose per pulse shall be 500 ±200
rad(Si) with a pulse width between 20 and 100 ns, inclusive. Circuits shall be exposed to radiation pulses in at least two
difference states (for digital devices) as specified in the test plan or procedure. Unless otherwise specified, determination of
latchup shall be based on a combination of DUT supply current and output signal (voltage) recovery within the specified time
limits and the results of post-irradiation in-situ functional tests. Power supplied to the DUT shall not be interrupted until after
the post-irradiation in-situ tests are completed. The DUT supply current shall be measured immediately before and at the
specified time after the radiation pulse to determine if the supply current has returned to within specified limits. A functional
test shall be performed immediately after the recovery period to demonstrate that the device functions properly. Unless
otherwise specified, tests shall be performed at the highest device operating temperature in the system application or 15°C
below the maximum rated temperature of the device, whichever is less. Current limiting resistors are allowed only if prior
approval is obtained from the acquiring activity and the value of the resistor is less than or equal to that in the system
application. Unless otherwise specified, endpoint electrical tests (group A, subgroups 1 and 7, as a minimum) shall be
performed pre- and post-latchup testing. These group A tests are generally not performed in-situ, and there is no time limit
on performing the group A tests. If group A testing is performed as part of another test (e.g., post-burn in, final electrical
acceptance), the group A tests need not be duplicated as long as the test sequence is: Group A tests - latchup testing -
group A tests.
3.5.2 Production test sequence
.
CAUTION: Exercise caution when handling devices, particularly with regard to pin alignment in the carriers and holding
fixture and when attaching devices to the test circuit. Insure that bias voltage are off before attachment. Observe ESD
handling procedures for the class of devices being tested.
The latchup test system, including test circuitry, cables, monitoring, and recording equipment, shall be assembled to provide
the specified biasing and output monitoring. Place the DUT in position for the specified dose; ensure that the system is
functioning as follows:
Step 1: Apply and verify the bias voltages at the interface fixture with the device removed.
Step 2: Adjust timing control system to provide the required time interval between radiation pulse and post-
irradiation measurements.
Step 3: Remove bias voltages and install a control sample device (identical to devices to be tested).
Step 4: Turn on bias voltages and verify proper device function in accordance with performance requirements.
Step 5: Verify proper operation of all recording, monitoring, and timing control equipment.
Step 6: Remove bias voltages and control device, in that order.
MIL-STD-883F
METHOD 1020.1
15 November 1991
6
Adjust the radiation source to operate in the specified mode to deliver the specified dose. Verify as follows:
Step 7: Put dosimetry in position and expose to radiation pulse. Verify that the dose recording equipment is working
properly and that the appropriate dose was delivered.
When the latchup test system, radiation source, and dosimetry system have been verified to be working properly, continue
as follows for each device type to be tested:
3.5.2.1 Combinational logic
. Latchup tests for combinational logic circuits shall be performed as follows:
Step 8: Install the DUT in the proper position in front of the radiation source, and bring the device to test
temperature.
Step 9: Bias the device in accordance with the test plan or procedure and verify proper device functional operation.
Step 10: Load the specified test pattern and verify correct output conditions.
Step 11: Irradiate the device (maintaining above input condition) and record the dose and parameters required by the
test plan or procedure.
Step 12: To verify recovery time, measure the DUT supply current at the specified time after the radiation pulse.
Verify that the supply current and output voltages have returned to within the specified limits.
Step 13: Perform another functional test and determine if the device passes.
Step 14: Put the device in complement state and repeat steps 10-13. (The number of states in which the device is to
be tested shall be specified in the test plan or procedure.)
Step 15: Remove bias voltages and device, in that order.
A combinational device fails the latchup test if the output after the recovery time is not in the proper state, it fails the post-
irradiation in-situ functional test, or if the supply current does not return to within specified limits within the specified time
after irradiation.
3.5.2.2 Sequential logic
. Latchup tests for sequential logic circuits shall be performed as follows:
Step 8: Install the DUT in the proper position in front of the radiation source, and bring the device to test
temperature.
Step 9: Bias the device in accordance with the test plan or procedure and verify proper device functional operation.
Step 10: Load the specified test pattern and verify correct output conditions.
Step 11: Irradiate the device (maintaining above input condition) and record the dose and parameters required by the
test plan or procedure.
Step 12: To verify recovery time, measure the DUT supply current at the specified time after the radiation pulse.
Verify that the supply current and output voltages have returned to within the specified limits.
Step 13: Perform functional test to determine if the device passes.