IEC 60749-8 pdf download – Semiconductor devices – Mechanical and climatic test methods – Part 8: Sealing

IEC 60749-8 pdf download – Semiconductor devices – Mechanical and climatic test methods – Part 8: Sealing\
1 Scope and object
This part of lEC 60749 is applicable to semiconductor devices (discrete devices andintegrated circuits)
The object of this test method is to determine the leak rate of semiconductor devices.
NOTE This test is identical to the test method contained in clause 5 of chapter 3 of IEC 60749(1996), amendment2,apart from the addition of this clause and clause 2 and the subsequent renumbering.
Normative references
The following referenced documents are indispensable for the application of this document.For dated references, only the edition cited applies.For undated references, the latest editionof the referenced document (including any amendments) applies.
IEC 60068-2-17:1994, Environmental testing – Part 2: Tests – Test Q: Sealing
3General terms
3.1Units of pressure
The International System of Units (Sl) recommends the use of the Pascal (Pa) as the unit ofpressure.The commonly used units are, however, the absolute atmosphere or the bar (where1 absolute atmosphere = 1 bar = 105 Pa). The unit used in this test method is the Pascal withthe bar used as an alternative.
3.2 Standard leak rate
The standard leak rate is defined as that quantity of dry air at 25 C in pascals (bars) cubiccentimeters flowing through a leak or multiple leak paths per second when the high-pressureside is at 105 Pa ( 1 bar) and the low-pressure side is at a pressure of not greater than 102 Pa(10-3 bar).The standard leak rate shall be expressed in units of pascals cubic centimetresper second (bars cubic centimetres per second).
3.3Measured leak rate
The measured leak rate R(He) is defined as the leak rate of a given package as measuredunder specified conditions and employing a specified test medium. The measured leak rateshall be expressed in units of pascals cubic centimetres per second (bars cubic centimetresper second).For the purpose of comparison with rates determined by other methods oftesting, the measured leak rates must be converted to equivalent standard leak rates.
3.4Equivalent standard leak rate
The equivalent standard leak rate(L) of a given package,with a measured leak rate R(He),is detined as the leak rate of the same package with the same leak geometry, that would existunder the standard conditions of 3.2.The formula in 6.3 (which does not apply to test
condition 5) represents the LRratio and gives the equivalent standard leak rate (L) of thepackage with a measured leak rate R(He), where the package volume and leak test
conditioning parameters influence the measured value of R(He).The equivalent standard leakrate shall be expressed in units of units of pascals cubic centimetres per second (bars cubiccentimeters per second).
4Bomb pressure test
Reference: lEC 60068-2-17.
This test shall be in accordance with test Ql, with the following specific requirements:
– test liquid: 95 % methyl alcohol and 5 % water mixture, with addition of a detergent;temperature of the test liquid:
25 C±5°C;
pressure:4,5-105Pa (4,5 bar);
duration of conditioning:16 h;cleaning liquid:de-ionized water;
-recovery:between two days and two weeks.
NOTE The use of this test is not recommended for semiconductor devices (see annex F to IEC 60068-2-17).
5Fine leak detection: radioactive krypton method
Reference: none.
5.1Object
To determine the leak rate of a semiconductor device by measuring the radiation level presentwithin the device after it has been pressurized in a chamber with suitable radioactive tracergas.
This method is intended to be specified for devices which are designed to be hermeticallysealed in glass, metal or ceramic (or combination thereof) encapsulations and is suitable forequivalent standard leak rates smaller than 1 Pacm 3s-1 (10-5 bar-cm 3-s-1).
5.2General description
5.2.1 The numerical values given are applicable for krypton 85 tracer gas and for equivalentstandard leak rate limit in the order of 5. 10-3 Pacm 3-s-1(5-10-8 bar-cm 3·s-1). The use ofother tracer gases would require other numerical values.