MIL- STD-883F 2004 TEST METHOD STANDARD MICROCIRCUITS - 第114页

MIL-STD-883F METHOD 1018.4 18 June 2004 4 3.2.1 Fai lure c rit eria . a. A devic e which has a water -vapor c ontent (by vol ume) great er than t he speci fied maximum value s hall c onsti tute a failure . b. Aft er remo…

MIL-STD-883F

METHOD 1018.4

18 June 2004

Surface conductivity sensors may not be used in metal packages without external package wall insulation. When used, the

sensor shall be the coolest surface in the cavity. It should be noted that some surface conductivity sensors require a higher

ionic content than available in ultraclean CERDIP packages. In any case, correlation with mass spectrometer procedure 1

shall be established by clearly showing that the sensor reading can determine whether the cavity atmosphere has more or

less than the specified moisture limit at 100°C.

3. PROCEDURE

. The internal water-vapor content test shall be conducted in accordance with the requirement of

procedure 1, procedure 2, or procedure 3. All devices shall be prebaked for 16-24 hours at 100°C ±5°C prior to hot insertion

into apparatus. External ovens shall have a means to indicate if a power interruption occurs during the prebaking period and

for how long the temperature drops below 100 ±5°C. Devices baked in an external oven which loses power and whose

temperature drops below 100 ±5°C for more than 1 hour shall undergo another prebake to begin a minimum of 12 hours

later.

Note: It is recommended that samples submitted to the labs shall include information about the manufacturing process

including sealing temperature, sealing pressure, sealing gas, free internal cavity volume, lid thickness at puncture site, lid

material, and the location of the puncture site.

3.1 Procedure 1

. The device shall be hermetic in accordance with test method 1014, and free from any surface

contaminants which may interfere with accurate water-vapor content measurement. The internal water-vapor content

laboratory is not required to test for hermeticity in accordance with Test Method 1014 of MIL-STD-883.

After device insertion, the device and chamber shall be pumped down and baked out at a temperature of 100°C ±5°C until

the background pressure level will not prevent achieving the specified measurement accuracy and sensitivity. After

pumpdown, the device case or lid shall be punctured and the following properties of the released gases shall be measured,

using the mass spectrometer:

a. The increase in chamber pressure as the gases are released by piercing the device package. A pressure rise of

less than 50 percent of normal for that package volume and pressurization may indicate that (1) the puncture was

not fully accomplished, (2) the device package was not sealed hermetically, or (3) does not contain the normal

internal pressure.

b. The water-vapor content of the released gases, as a percent by unit volume or parts per million volume (ppmv) of

the total gas content.

c. The proportions (by volume) of the other following gases: N

, He, Mass 69 (fluorocarbons), O

, Ar, H

, CO

, CH

, and other solvents, if available. Calculations shall be made and reported on all gases present greater than

.01 percent by volume. Data reduction shall be performed in a manner which will preclude the cracking pattern

interference from other gas specie in the calculations of moisture content. Data shall be corrected for any system

dependent matrix effects such as the presence of hydrogen in the internal ambient.

3.1.1 Failure criteria

a. A device which has a water-vapor content greater than the specified maximum value shall constitute a failure.

b. A device which exhibits an abnormally low total gas content, as defined in 3.1a, shall constitute a failure, if it is not

replaced. Such a device may be replaced by another device from the same population; if the replacement device

exhibits normal total gas content for its type, neither it nor the original device shall constitute a failure for this cause.

3.2 Procedure 2

. The device shall be hermetic in accordance with test method 1014, and free from any surface

contaminants which may interfere with accurate water-vapor content measurement.

After device insertion into the piercing chamber, gas shall be flowed through the system until a stable base-line value of the

detector output is attained. With the gas flow continuing, the device package shall then be pierced so that a portion of the

purge gas flows through the package under test and the evolved moisture integrated until the base-line detector reading is

again reached. An alternative allows the package gas to be transferred to a holding chamber which contains a moisture

sensor and a pressure indicator. System is calibrated by injecting a known quantity of moisture or opening a package of

known moisture content.

MIL-STD-883F

METHOD 1018.4

18 June 2004

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

, where C

= correction factor (temperature), T

= room temperature (°C), T

= sealing temperature (°C).

For package volumes of any size sealed under vacuum conditions:

C =

, C

= correction factor (pressure), P

= sealing pressure, P

= 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

, where C

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. 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.