IEC 61189-5-502 pdf – Test methods for electrical materials, printed board and other interconnection structures and assemblies – Part 5-502: General test methods for materials and assemblies – Surface Insulation Resistance (SIR) testing of assemblies
1 Scope
This part of lEC 61189 is used for evaluating the changes to the surface insulation resistance
of a pre-selected material set on a representativetest coupon and quantifies the deleteriouseffects of improperly used materials and processes that can lead to decreases in electricalresistance.
An assembly process involves a number of different process materials including solder flux,solder paste,solder wire,underfill materials，adhesives， staking compounds,temporarymasking materials,cleaning solvents,conformal coatings and more. The test employs twodifferent test conditions of 85 C and 85 % relative humidity(RH), preferred for a process that
includes cleaning, or 40 °C and 90 % relative humidity (RH), preferred for processes where nocleaning is involved.
NOTE 40 ℃ and 93 % RH can be used as an alternative to 40 “C and 90 % RH. Aditional information is providedin 5.4 and A.5.2.
Testing is material (set) and process / equipment specific.Qualificationsare to be performedusing the production intent equipment,processes and materials.
2Normative references
The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document. For dated references, only the edition cited applies.
For undated’references,the latestedition of the referenced document (including anyamendments) applies.
IEC 60068-1，Environmental testing – Part 1: General and guidance
IEC 60068-2-20, Environmental testing – Part 2-20: Tests – Test T: Test methods forsolderability and resistance to soldering heat of devices with leads
IEC 60068-2-58, Environmental testing – Part 2-58: Tests – Test Td: Test methods forsolderability, resistance to dissolution of metallization and to soldering heat of surface mounting
devices (SMD)
IEC 60068-2-67，Environmental testing – Part 2-67:Tests -Test Cy: Damp heat, steady state,accelerated test primarily intended for components
IEC 60068-2-78,Environmental testing – Part 2-78:Tests – Test Cab: Damp heat, steady stateIEC 60194，Printed board design, manufacture and assembly – Terms and definitions
IEC 61190-1-3, Attachment materials for electronic assembly – Part 1-3: Requirements forelectronic grade solder alloys and fluxed and non-fluxed solid solder for electronic solderingapplications
3Terms and definitions
For the purposes of this document, the terms and definitions given in lEC 60068-1, IEC 60068-2-20:2008,IEC 60068-2-58,IEC 60194,and lEC 61190-1-3 and the following apply.
lSO and lEC maintain terminological databases for use in standardization at the followingaddresses:
. IEC Electropedia: available at http://www.electropedia.orgl
– lso Online browsing platform: available at http://www.iso.org/obp
3.1
test coupon
test specimen, test vehicle, test sample
4Equipment/Apparatus
4.1Soldering and other production process equipment
All the equipment shall represent the equipment to be used in production.
4.2Measurement instrument
This shall consist of a measuring device capable of measuring insulation resistance in the rangeof at least 10 6 Q to 10 12 Q.
lt shall be capable of measuring and recording each individual test pattern of an lPC-B-52 test
board/assembly. The measurement circuit shall incorporate a 1 MQ current limiting resistor ineach current pathway.
The tolerance of the total measurement system shall be:. 士5 % up to 10 10 Q at 5 v;
.士10 % between 10 1o Q to 1011 at 5 v;- ±20 % above 10 11 Qat 5 v.
lf a different test voltage is to be used, the measurement circuit shall be assessed at that voltage
rather than the 5v stipulated. See 6.8 and Clause A.12 for additional information on testvoltages.
The resistors used to confirm the “total measurement system tolerance” defined above，shallhave a purchased tolerance of:
0,1 % up to and including 106 Q;
1 % above 10 6 and up to and including 108 Q;
5 % above 10 8 Q and up to and including 1010 Q;
10 % above 10 10 Q.
The instrument can be used with either an external or internal power supply but shall be capableof delivering a variable voltage from (5 to 100)v DC±1 % with a 1 M load and a channel to channel isolation resistance of 1013 Q.
Equipment shall have the measurement capability to repeat the resistance measurement on all channels at least every 20 min.
4.3 Resistor verification coupon The measurement system measurement performance shall be verified by substituting a resistor verification coupon (see Figure 1) in place of the test coupons while in the chamber at both ambient and elevated conditions. This coupon should be fitted with at least 4 “known value” resistors. The tolerances for the “known value” resistors shall be as per the purchased tolerances detailed in 4.2.