MIL-PRF-38535K
APPENDIX A
A.4.5.8.3 Group C failure. When a group C failure occurs, samples from subsequent wafer lots submitted for
acceptance in the same microcircuit group (see A.3.1.3.13), produced on the same die fabrication line, and started
(or completed at the manufacturer's option) die fabrication during the same year shall be subjected to group C. The
testing shall be performed on a wafer-lot-by-wafer-lot basis until three consecutively tested wafer lots from the same
microcircuit group and year of fabrication pass group C; the testing may then return to periodic testing. A device type
that fails a group C inspection shall not be accepted until the device type that failed successfully completes group C.
In addition, any other inspection lots using die from the same failed wafer lot shall successfully complete group C
prior to shipment until three successive inspection lots from the same wafer lot have passed group C using a
tightened sample size number (accept number) with C = 0. In the event of a group C failure, the manufacturer shall
evaluate the possible impact on product that has been manufactured since the last acceptable group C test (based
on wafer fab code), from the failed microcircuit group.
A.4.5.8.4 Group D failure. When a failure occurs for a group D subgroup(s), samples from subsequent lots
submitted for acceptance of the same package family and lead finish shall be subjected to all the tests in the failed
subgroup(s). The testing shall be performed on a lot-by-lot basis until three successive lots of the same package
family pass the failed subgroup(s). Testing of the package family may then return to periodic testing. The package
type that failed the group D subgroup(s) shall be tested on a lot-by-lot basis until three successive lots pass the failed
subgroup(s) at which time it may return to periodic inspection coverage. Under the worst case conditions option,
when a glass sealed package fails, every package type in the package family shall pass the failed group D subgroup,
prior to shipping the device. Failed package types shall be tested on a lot-by-lot basis until three successive lots of
the same package type pass the failed subgroup(s) at which time it may return to periodic inspection. In the event of
a group D failure, the manufacturer shall evaluate the possible impact on product that has been manufactured since
the last acceptable group D (based on seal or encapsulation date code), for the failed package family.
A.4.6 Screening. Each microcircuit shall have been subjected to and passed all the screening tests detailed in
table IA as specified herein or TM 5004 or TM 5010, as applicable, of MIL-STD-883 for the specified quality
assurance level and type of microcircuit in order to be acceptable for delivery. When a PDA (see A.3.1.3.14 and TM
5004 or TM 5010 of MIL-STD-883) or delta limits (see A.3.1.3.15) has been specified or other conditions for lot
acceptance have been imposed, the required data shall be recorded and maintained as a basis for lot acceptance.
Devices that fail any test criteria in the screening sequence shall be removed from the lot at the time of observation or
immediately at the conclusion of the test in which the failure was observed. Once rejected and verified as a device
failure, no device may be retested for acceptance.
A.4.6.1 Burn-in. Burn-in shall be performed on all microcircuits where specified and the specified pre- and post-
burn-in electrical parameters shall be measured.
A.4.6.1.1 Lots and sublots resubmitted for burn-in. Inspection lots, lot splits, and class level S sublots may be
resubmitted for burn-in one time only and may be resubmitted only when the observed percent defective does not
exceed twice the specified PDA (10 percent) or 2 devices, whichever is greater. Any lot that exceeds the allowable
resubmission PDA, (greater than 10%, but less than 20%), the manufacturer may resubmit the lot provided analysis
is performed to a level sufficient to determine the mechanism of failure for the lot with TRB approval and written
notification (letter or email) to the Qualifying Activity prior to shipment. The lot may be resubmitted using tightened
inspection criteria. Resubmitted inspection lots, lot-splits, and class level S sublots shall contain only parts which
were in the original lot or sublot. Resubmitted inspection lots, lot splits, and class level S sublots shall be kept
separate from new lots and sublots and shall be inspected for all specified characteristics using a tightened
inspection PDA equal to the next lower number in the sample size series (see appendix D), or one device, whichever
is greater.
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ACTEL [ Actel Corporation ]
