Test Lab Services - Fine Gross Leak Testing via Radiflo Radioisotope: Krypton–85 (Kr85)

Test & Lab Services
Fine & Gross Leak Testing via Radiflo®
Radioisotope: Krypton–85 (Kr85)
Hermeticity Lab Services
Micross’ Fine & Gross leak testing service for hermetically
packaged semiconductor devices relies on the use of
Krypton–85 Radioisotope, a tracer gas and the Radiflo®
process. This highly sensitive method, initially developed in
1955 and benefiting from continuous enhancements and
simplification of isotope handling has delivered to the industry
a highly accurate, sophisticated method for performing
hermeticity validation testing. This method provides the
benefit of being extremely fast while providing improved leak
rate detection to <10-12 atm cc/sec. Additionally, the Radiflo®
process is currently one of very few methods which will
perform both Fine & Gross leak while mitigating risk for test
escapees associated with Fluorocarbon masking. It therefore
is considered a preferred method for components being
sourced to critical Aerospace, Military and Medical platforms
Test Procedure
The Krypton–85
equation is defined as:
QS =
R
(S)(K)(T)(P)(t)
QS = Leak reject rate (atm cc/sec Kr)
R = Detector reject level (cpm)
S = Specific activity (uCi/atm cc)
K = counting efficiency (cpm/uCi)
P = (Pe2 – Pi2)
Pe2 = external bomb pressure (atm)
Pi2 = internal pressure of device (atm)
Devices to be tested for hermeticity are placed into a
specialized test chamber, pressurized with purified dry air
and small amounts of the Radioisotope, Kr85 gas. This
pressurized, radioisotope tracer condition is specified by the
Krypton–85 equation which determines the pressure limit and
length of bomb time based on the device’s cavity size and
desired reject leak rate.
After completion of the pressurization cycle, the devices are
removed from the Radiflo pressurization tank, taken to a
counting station which utilizes a scintillation crystal to detect
extremely small quantities of Kr85. If detected, the count will
be registered and based on the customer desired reject leak
rate, a pass/fail criteria registered.
Supported Test Standards
T = Bomb time (hours)
t = 3600 (sec/hr.)
Test Method
Test Conditions
MIL-STD-750
1071
A, B, G1 & G2
MIL-STD-883
1014
B1, B2 & B2/B1 Combination
August 7, 2015 • Revision 1.0
7725 N.
Blossom
Trail • Orlando,
FL 32810
• &407.298.7100
• [email protected]
Micross
USOrange
(Americas)
407.298.7100
• Micross
UK (EMEA
ROW) +44 (0) 1603
788967 • [email protected]• •www.micross.com
www.micross.com
Form #: CSI-D-721 Document 001
Fine & Gross Leak Testing via Radiflo®
Radioisotope: Krypton–85 (Kr85)
Technology
Krypton–85 is a radioactive inert gas that emits weak gamma rays and
beta particles. The detectability of the gas is millions of times greater than
the detection of helium in a mass spectrometer leak test, thus much shorter
bomb times, greater accuracy with no negative impact issues due to use of
fluorocarbon liquids as part of a Gross leak test. Additionally, test accuracies
of extremely small cavities is improved for fine leak detection due to the
properties of the tracer gas therefore reducing risk that a fine leak device has
escaped due to loss of helium contained within the ultra-small cavity prior
to detection.
Micross Services
We are currently providing our Radiflo® process on many of the standard
hermetic semiconductor packaging footprints. Current available lead times
are for either a standard one-week turn, or for our customer’s convenience,
three-day expedited services. We also offers our Radiflo® process on many
additional standard package footprints; please contact your sales professional
for a lead time quotation. For other packaging footprints including high I/O
leaded devices and non-standard footprints please consult the factory.
Hermetic Packages
3
4
6
8
10
12
14
16
18
20
22
24
28
32
36
40
44
48
52
56
64
68
84 100+
Ceramic DIP (300 MIL)
Ceramic DIP (400 MIL)
Ceramic DIP (600 MIL)
Ceramic Flact Pack (FP)
Ceramic LCC (CLCC)
Ceramic PGA (Pin Grid Array)
*
Ceramic Quad Flat Pack (CQFP)
*
Ceramic J Quad Flat Pack (CJQFP)
*
*
Hybrid Packages
TO Metal Packaging
TO3
TO5
*
*
TO18
*
*
TO39
*
*
TO72
*
*
TO99
*
*
TO100
*
*
TO257
*
*
TO258
*
*
*
*
*
*
TO259
Metal Can
Metal Tab
Metal Z-Tab
Standard one-week turnaround as well as expedite service available
Consult factory for current lead times
* Consult factory
August 7, 2015 • Revision 1.0
Micross US (Americas) 407.298.7100 • Micross UK (EMEA & ROW) +44 (0) 1603 788967 • [email protected] • www.micross.com
Form #: CSI-D-721 Document 001