MIL- STD-883F 2004 TEST METHOD STANDARD MICROCIRCUITS.pdf - 第115页

MIL-STD-883F METHOD 1018.4 18 June 2004 5 5. SUMMARY . The fol lowing detai ls s hall be s pecif ied in t he applic able acqui sit ion document : a. The pr ocedur e (1, 2, or 3) when a s pecif ic pr ocedure i s to be us …

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MIL-STD-883F
METHOD 1018.4
18 June 2004
4
3.2.1 Failure criteria
.
a. A device which has a water-vapor content (by volume) greater than the specified maximum value shall constitute a
failure.
b. After removal from the piercing chamber, the device shall be inspected to ascertain that the package has been fully
opened. A device package which was not pierced shall constitute a failure, if the test is not performed on another
device from the same population; if this retest sample or replacement is demonstrated to be pierced and meets the
specified water-vapor content criteria, the specimen shall be considered to have passed the test.
c. A package which is a leaker in the purge case will be wet and counted as a failure. In the case of evacuation, a
normal pressure rise shall be measured as in 3.1a.
3.3 Procedure 3
. The moisture sensor shall be calibrated in an atmosphere of known water-vapor content, such as that
established by a saturated solution of an appropriate salt or dilution flow stream. It shall be demonstrated that the sensor
calibration can be verified after package seal or that post seal calibration of the sensor by lid removal is an acceptable
procedure.
The moisture sensor shall be sealed in the device package or, when specified, in a dummy package of the same type. This
sealing shall be done under the same processes, with the same die attach materials and in the same facilities during the
same time period as the device population being tested.
The water-vapor content measurement shall be made, at 100°C or below, by measuring the moisture sensor response.
Correlation with procedure 1 shall be accomplished before suitability of the sensor for procedure 3 is granted. It shall be
shown the package ambient and sensor surface are free from any contaminating materials such as organic solvents which
might result in a lower than usual moisture reading.
3.3.1 Failure criteria
. A specimen which has a water-vapor content greater than the specified maximum value shall
constitute a failure.
4. IMPLEMENTATION
. Suitability for performing method 1018 analysis is granted by the qualifying activity for specific
limits and volumes. Method 1018 calibration procedures and the suitability survey are designed to guarantee ±20 percent
lab-to-lab correlation in making a determination whether the sample passes or fails the specified limit. Water vapor contents
reported either above or below the (water vapor content - volume) range of suitability are not certified as correlatable values.
This out of specification data has meaning only in a relative sense and only when one laboratory's results are being
compared. The specification limit of 5,000 ppmv shall apply to all package volumes, with the following correction factors
permitted to be used, provided they are documented and shown to be applicable:
For package volumes less than .01 cc internal free volume which are sealed while heated in a furnace:
273
273
+
+
=
s
r
T
T
T
C
, where C
T
= correction factor (temperature), T
r
= room temperature (°C), T
s
= sealing temperature (°C).
For package volumes of any size sealed under vacuum conditions:
a
s
P
P
P
C =
, C
P
= correction factor (pressure), P
s
= sealing pressure, P
a
= atmospheric pressure (pressures may be in either
Torr or mm Hg).
The correction factor, if used, shall be applied as follows:
Water Vapor (Corrected) = Water Vapor (Measured) x C
X
, where C
X
is the applicable correction factor.
The range of suitability for each laboratory will be extended by the qualifying activity when the analytical laboratories
demonstrate an expanded capability. Information on current analytical laboratory suitability status can be obtained by
contacting DSCC-VQ.
*
MIL-STD-883F
METHOD 1018.4
18 June 2004
5
5. SUMMARY
. The following details shall be specified in the applicable acquisition document:
a. The procedure (1, 2, or 3) when a specific procedure is to be used (see 3).
b. The maximum allowable water-vapor content falling within the range of suitability as specified in test method 5005,
5008, or 5010, or general specifications MIL-PRF-38534 or MIL-PRF-38535.
MIL-STD-883F
METHOD 1018.4
18 June 2004
6
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