MIL- STD-883F 2004 TEST METHOD STANDARD MICROCIRCUITS - 第171页

MIL-STD-883F METHOD 1032.1 29 May 1987 3 f. The flux at t he surf ace of t he die will be determi ned when the die c oat is in plac e; this is designat ed as the modifi ed package f lux. NOTE: The modif ied pack age flux…

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MIL-STD-883F
METHOD 1032.1
29 May 1987
2
2.3 Test circuits
. The test circuit shall contain the DUT, wiring, and auxiliary components as required. Connection will
allow for the application of the specified test conditions to obtain the specified outputs. Provision will be made for monitoring
and recording the specified outputs. Any loading of the output(s), such as resistors or capacitors, shall be specified. The
test circuit must not exhibit permanent changes in electrical characteristics as a result of exposure to the radioactive source.
Shielding will be incorporated to prevent such effects from occurring if necessary.
2.4 Cabling
. Cabling, if required, shall be provided to connect the test circuit board containing the DUT to the test
instrumentation. All cables will be as short as possible. Care will be exercised to reduce electrical noise induced by the
cable by using shielded cable, triax, zipper tubing, or other shielding methods.
3. PROCEDURES
. Two methods of testing are allowed by this procedure. The first is a long term test (sometimes
referred to as a system test) which does not incorporate a source but which accumulates a statistically valid amount of test
time to determine the SER directly. This method is self explanatory and must be accomplished using the same parameters
outlined in 3.1 (test plan). To determine the SER from this method, the following formula should be used and the result
converted to FIT's.
SER = Total number of errors/Total test time
The second method incorporates the use of the source outlined in 2.1 (radiation source). The procedure for testing with an
accelerated flux provided by the source is given below. These steps will be followed for each test outlined in 3.1.
a. The flux that the surface of the die would receive without a die coat will be determined. This is designated as the
package flux.
b. If the device has a die-coat it should be left in place for the next portion of the test. The DUT will be delidded and
the source placed directly over the die cavity at the same distance as the package lid was from the die.
NOTE: The distance between the foil and the die must be less than 50 mils and the foil must cover the entire die-
cavity opening in order to assure all angles of incidence will be maintained.
NOTE: If the DUT has an inverted die configuration (e.g., flip-chip) a test jig must be implemented which will
expose the active surface of the die to the irradiating source.
c. The testing outlined in 3.1 will be performed at this time with the configuration in b. above, in order to determine
the SER for each test performed.
d. Recorded for each test performed will be the following:
(1) Total number of errors recorded during each test.
(2) Time to accumulate the errors.
(3) SER
1
, calculated from the following formulas:
ASER
1
= Total number of errors/test time
SER
1
= ASER
1
x (Package flux/source flux)
e. If no die-coating has been applied, the SER
1
will be reported as the measured rate of failure. However, if a die
coat exists, steps 3.f through 3.j will also be performed.
MIL-STD-883F
METHOD 1032.1
29 May 1987
3
f. The flux at the surface of the die will be determined when the die coat is in place; this is designated as the
modified package flux.
NOTE: The modified package flux should be the sum of the flux from the die and die-coat material only.
g. The die coat should be removed, assuring that no damage to the die has occurred and the source placed as
described in step b.
h. The tests performed in step 3.c must be repeated with this configuration, and the new SER will be designated
SER
2
.
i. Recorded for each test performed will be the following:
(1) Total number of errors recorded during each test.
(2) Time to accumulate the errors.
(3) SER (SER
2
), calculated from the following formulas:
ASER
2
= Total number of errors/test time
SER
2
= ASER
2
x (Modified package flux/source flux)
j. The SER for the corresponding tests will be summed and reported as the rate of failure for this DUT, using the
following formula:
SER = SER
1
+ SER
2
NOTE: The order of the steps above can be reversed to enable testing before the die coat is applied and then after it has
been applied, if desired.
3.1 Test plan
. A test plan will be devised which will include determination of the worst case operating environment of the
DUT to determine the worst case SER, incorporating the steps outlined above. The data patterns used will ensure that each
cell and path, or both, is tested for both the logic zero and logic one states. The device will be continuously monitored and
refreshed and the data errors counted. This test will be required for each new device type or design revisions. The source
value and exposure time will be sufficient to obtain a significant number of soft error failures.
NOTE: If a data-retention or a reduced supply mode is a valid operating point for the DUT, this condition must also be
tested for its SER.
3.1.1 The test equipment program
. The test equipment program will be devised to cycle and refresh the stored data or
cycled pattern continually, recording the number of errors.
3.1.2 Test conditions
. Testing shall be performed at three separate cycle rates and at minimum and maximum voltages.
Unless otherwise specified, the following cycle timing will be used: The minimum and the maximum specified cycle timing
and the midpoint between the minimum and maximum specified cycle timing.
NOTE: If the device is a static or dynamic random access memory device, the device will be tested under both read and
write operations.
3.2 Report
. As a minimum, the report will include device identification, test date, test operator, test facility (if applicable),
radiation source, test cycle times and voltages, data analysis, and equipment used in the test.
MIL-STD-883F
METHOD 1032.1
29 May 1987
4
4. SUMMARY
. The following details shall be specified.
a. Device type and quantity to be tested.
b. Test circuit to be used.
c. Device output pins to be monitored.
d. Alpha source used if other than specified herein.
e. Alpha source Curie level.
f. Package flux measurement techniques.
g. Test equipment to be used.
h. Procedures for proper handling of radioactive materials.