MIL-STD-883G

METHOD 1014.12

28 February 2006

METHOD 1014.12

SEAL

1. PURPOSE

. The purpose of this test is to determine the effectiveness (hermeticity) of the seal of microelectronic and

semiconductor devices with designed internal cavities

1.1 Definitions

a. Standard leak rate. Standard leak rate is defined as that quantity of dry air at 25°C in atmosphere cubic

centimeters flowing through a leak or multiple leak paths per second when the high-pressure side is at 1

atmosphere (760 mm Hg absolute) and the low-pressure side is at a pressure of not greater than 1 mm Hg

absolute. Standard leak rate shall be expressed in units of atmosphere cubic centimeters per second (atm cc/s).

b. Measured leak rate. Measured leak rate (R

) is defined as the leak rate of a given package as measured under

specified conditions and employing a specified test medium. Measured leak rate shall be expressed in units of

atmosphere cubic centimeters per second (atm cc/s). For the purpose of comparison with rates determined by

other methods of testing, the measured leak rates must be converted to equivalent standard leak rates.

c. Equivalent standard leak rate. The equivalent standard leak (L) of a given package, with a measured leak rate

), is defined as the leak rate of the same package with the same leak geometry that would exist under the

standard conditions of 1.1a. The formula (does not apply to test condition B) in 3.1.1.2 represents the L/R ratio

and gives the equivalent standard leak rate (L) of the package with a measured leak rate (R

) where the package

volume and leak test conditioning parameters influence the measured value of (R

). The equivalent standard leak

rate shall be expressed in units of atmosphere cubic centimeters per second (atm cc/s).

2. APPARATUS

. The apparatus required for the seal test shall be as follows for the applicable test condition:

2.1 Test conditions A

, A

, and A

, 1/ tracer gas helium (He) fine leak. Apparatus required shall consist of suitable

pressure and vacuum chambers and a mass spectrometer-type leak detector preset and properly calibrated for a helium

leak rate sensitivity sufficient to read measured helium leak rates of 10

-9

atm cc/s and greater. The volume of the chamber

used for leak rate measurement should be held to the minimum practical, since this chamber volume has an adverse effect

on sensitivity limits. The leak detector indicator shall be calibrated using a diffusion-type calibrated standard leak at least

once during every working shift. In addition for test condition A

, the following apparatus is required:

a. Fixture and fittings to mate the package to be tested to the leak detector.

b. Surgical rubber gasket.

c. Apeizon grease (type M or N), perfluorocarbon fluid 2

/, or equivalent, if required to obtain seal.

/ A

was intentionally omitted.

/ Perfluorocarbons contain no chlorine or hydrogen.

MIL-STD-883G

METHOD 1014.12

28 February 2006

2.2 Test condition B

, radioisotope fine leak. Apparatus for this test shall consist of:

a. Radioactive tracer gas pressurization console.

b. Counting equipment consisting of a scintillation crystal, photomultiplier tube, preamplifier, ratemeter, and

krypton-85 reference standards. The counting station shall be of sufficient sensitivity to determine through the

device wall the radiation level of any krypton-85 tracer gas present within the device. The counting station shall

have a minimum sensitivity of 10,000 counts per minute per micro-curie of krypton-85 and shall be calibrated at

least once every working shift using krypton-85 reference standards and following the equipment manufacturer's

instruction.

c. A tracer gas that consists of a mixture of krypton-85 and dry nitrogen. The concentration of the krypton-85 in dry

nitrogen shall be no less than 100 micro-curies per atmospheric cubic centimeter. This value shall be determined

at least once each 30 days and recorded in accordance with the calibration requirements of this standard (see

4.5.1 of MIL-STD-883).

2.3 Test condition C, perfluorocarbon gross leak

. Apparatus for this test shall consist of:

a. A vacuum/pressure chamber for the evacuation and subsequent pressure bombing of devices up to 105 psia up

to 23.5 hours.

b. A suitable observation container with provisions to maintain the indicator fluid at a temperature of 125°C and a

filtration system capable of removing particles greater than 1 micrometer in size from the fluid (condition C1 only).

c. A magnifier with a magnification in the range between 1.5X to 30X for observation of bubbles emanating from

devices when immersed in the indicator fluid (condition C1 only).

d. Sources of type I detector fluids, and type II indicator fluids as specified in table I.

e. A lighting source capable of producing at least 15 thousand foot candles in air at a distance equal to that which

the most distant device in the bath will be from the source. The lighting source shall not require calibration but the

light level at the point of observation (i.e., where the device under test is located during observation for bubbles),

shall be verified (condition C1 only).

f. Suitable calibrated instruments to indicate that test temperatures, pressures, and times are as specified.

g. Suitable fixtures to hold the device(s) in the indicator fluid (condition C1 only).

h. A perfluorocarbon vapor detection system capable of detecting vapor quantities equivalent to 0.167 or 1/6

microliter of type I fluid (condition C3 only).

i. The vapor detector used for condition C3 shall be calibrated at least once each working shift using a type I fluid

calibration source, and following the manufacturer's instructions.

2.4 Test condition D, penetrant dye gross leak

. The following apparatus shall be used for this test:

a. Ultraviolet light source with peak radiation at approximately the frequency causing maximum reflection of the dye

(3650 Å for Zyglo; 4935 Å for Fluorescein; 5560 Å for Rhodamine B, etc.).

b. Pressure chamber capable of maintaining 105 psia.

c. Solution of fluorescent dye (such as Rhodamine B, Fluorescein, Dye-check, Zyglo, FL-50, or equivalent) mixed in

accordance with the manufacturer's specification.

d. A magnifier with a magnification in the range between 1.5X to 30X for dye observation.