IEC TR 61191-9:2023

IEC TR 61191-9 ®
Edition 1.0 2023-06
TECHNICAL
REPORT
colour
inside
Printed board assemblies –
Part 9: Electrochemical reliability and ionic contamination on printed circuit
board assemblies for use in automotive applications – Best practices
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IEC TR 61191-9 ®
Edition 1.0 2023-06
TECHNICAL
REPORT
colour
inside
Printed board assemblies –
Part 9: Electrochemical reliability and ionic contamination on printed circuit

board assemblies for use in automotive applications – Best practices

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.180; 31.190 ISBN 978-2-8322-7028-8

– 2 – IEC TR 61191-9:2023 © IEC 2023
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions and abbreviated terms . 8
3.1 Terms and definitions related to management . 9
3.2 Technical terms and definitions . 9
3.3 Abbreviated terms . 10
4 Failure mode electrochemical migration . 10
4.1 Background of electrochemical migration . 10
4.2 Complexity of electrochemical migration . 12
4.3 Conductive anodic filament (CAF) and anodic migration phenomena (AMP) . 13
4.4 Creep corrosion . 14
5 Electrochemical migration and relevance of ionic contamination . 15
5.1 General aspects . 15
5.2 Background of ionic contamination measurement . 15
5.3 Restrictions and limitations of ionic contamination measurement for no-clean
assemblies . 17
5.4 Restrictions and limitations of Ionic contamination measurement for cleaned
products . 28
5.5 How to do – Guidance to use cases . 37
5.6 Examples for good practice . 40
6 Surface insulation resistance (SIR) . 43
6.1 SIR – An early stage method to identify critical material combinations and
faulty processing . 43
6.2 Fundamental parameters of influence on SIR . 43
6.3 Harmonization of SIR test conditions for characterization of materials for
automotive applications . 51
6.4 Different steps of SIR testing . 51
7 Comprehensive SIR testing – B52-approach . 55
7.1 General aspects . 55
7.2 The main B52 test board . 56
7.3 The test patterns . 57
7.4 Processing of B52 boards . 59
7.5 Sample size for SIR testing of B52 test coupons . 59
7.6 Preparation for SIR testing . 59
7.7 Sequence of SIR testing . 60
7.8 Evaluation . 62
8 Example for good practice . 62
8.1 Methodology for material and process qualification, process control . 62
8.2 Step 1 – Material qualification . 62
8.3 Step 2 – Product design verification and process validation . 64
8.4 Step 3 – Definition of process control limits . 65
Annex A (informative) SIR measurement for SMT solder paste – Representative
example . 67
A.1 Purpose . 67
A.2 Equipment . 67

A.3 Example of an instruction how to perform the test . 67
Bibliography . 70

Figure 1 – Principal reaction mechanism of ECM . 11
Figure 2 – Uncertainty in local conditions determines ECM failures . 11
Figure 3 – Occurrence of ECM failures during humidity tests . 12
Figure 4 – VENN diagram showing the factors influencing ECM . 13
Figure 5 – Occurrence of CAF and AMP . 14
Figure 6 – Creep corrosion caused by corrosive gases . 15
Figure 7 – Ionic contamination measurement . 16
Figure 8 – Principal operation mode (fluid flow) of ROSE . 17
Figure 9 – Effect of solvent composition on the obtained ROSE results . 18
Figure 10 – Effect of solvent composition on the obtained ion chromatography result . 18
Figure 11 – Comparison of ROSE values with different solvent mixtures and material
variations of the CBA . 21
Figure 12 – Variation in ROSE values depending on technology used . 22
Figure 13 – Destructive action of solvent on resin matrix . 23
Figure 14 – Comparison of the resin change . 23
Figure 15 – Destructive action of solvent on resin matrix and chipping effect . 24
Figure 16 – Assembly manufactured with 2x SMT and 1x THT process for the
connector . 28
Figure 17 – Comparison of SPC-charts from 1-year monitoring of different CB
suppliers and two different iSn final finish processes . 29
Figure 18 – Differences in ROSE values for unpopulated CBs depending on the
extraction method . 30
Figure 19 – Reduction of ionic contamination on bare CBs (state of delivery from CB
supplier) by leadfree reflow step without solder paste or components . 32
Figure 20 – Influence of components on the ionic contamination based on
B52‑standard . 33
Figure 21 – Formation of a white veil or residue on MLCCs during active humidity test . 34
Figure 22 – Chromatogram derived from ion chromatography measurement of a
cleaned CBA . 36
Figure 23 – Approach for achieving objective evidence for a qualified manufacturing
process in the automotive industry . 41
Figure 24 – ROSE as process control tool . 42
Figure 25 – View on SIR measurement . 44
Figure 26 – Principal course of SIR curves . 45
Figure 27 – Response graph concerning stabilized SIR-value after 168 h from a DoE
with B53-similar test coupons (bare CB) . 45
Figure 28 – SIR measurement with B24-CB, no-clean SMT solder paste . 46
Figure 29 – Increase in ECM propensity depending on voltage applied (U) and Cu-Cu
distances (d) of comb structures . 48
Figure 30 – Layout of B53 test coupon . 49
Figure 31 – B53 with solder mask, partially covered and fully covered comb structures . 53
Figure 32 – B52 CBA after SMT process, layout slightly adapted to fulfil company
internal layout rules . 56

– 4 – IEC TR 61191-9:2023 © IEC 2023
Figure 33 – Pattern of B52 CB, layout slightly adapted to fulfill company internal layout
rules . 57
Figure 34 – Positive example of comprehensive SIR tests obtained for qualification of
a SMT process . 61
Figure 35 – Negative example of a contaminated B52-sample, tested by the sequence
of constant climate and cyclic damp heat climate . 61
Figure 36 – SIR test coupon, similar to B53, for principal material qualification . 63
Figure 37 – SIR test with constant climate and cyclic damp heat condition . 63
Figure 38 – B52 test board and example of SIR curve . 64
Figure 39 – Example of the product that was realized by the released materials and
process . 64
Figure 40 – Ionic contamination test results from 4 repetitions of PV samples . 65
Figure 41 – Results of ionic residue testing and calculation of upper control limit (UCL) . 65
Figure 42 – Run chart derived from 2 samples per month during mass production . 66

Table 1 – List of ions based on IPC-TM650, 2.3.28 [21] . 26
Table 2 – Fingerprint after ion chromatography of no-clean assembly shown in
Figure 16 . 27
Table 3 – Fingerprint after ion chromatography of bare CBs (state of delivery) . 31
Table 4 – Fingerprint after ion chromatography of a bare CB and the respective PBA in
uncleaned and cleaned condition . 35
Table 5 – Fingerprint after ion chromatography of an uncleaned CBA compared to the
cleaned CBA and after removing the components . 37
Table 6 – Common test conditions for basic material evaluation . 51
Table 7 – Recommended SIR test conditions for basic material- and process release
for the outer layer manufactured by a CB supplier. 55
Table 8 – List of materials for components with recommendations for minor
adaptations . 58
Table 9 – Sequence for SIR testing of B52-CBAs for general material- and process
qualification . 60

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PRINTED BOARD ASSEMBLIES –
Part 9: Electrochemical reliability and ionic contamination on
printed circuit board assemblies for use in automotive applications –
Best practices
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC TR 61191-9 has been prepared by IEC technical committee 91: Electronics assembly
technology. It is a Technical Report.
The text of this Technical Report is based on the following documents:
Draft Report on voting
91/1811/DTR 91/1825A/RVDTR
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Report is English.

– 6 – IEC TR 61191-9:2023 © IEC 2023
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 61191 series, published under the general title Printed board
assemblies, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates that it
contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.

INTRODUCTION
The document applies to electronic and electromechanical automotive circuit board assemblies.
It describes current best practices for dealing with electrochemical reactions like migration or
corrosion and ionic contamination on the surface of a printed circuit board as one failure mode
under humidity load.
This document is an informative document which serves to illustrate the technically feasible
options and provide a basis for customer and supplier agreements. It is not intended to be
regarded as a specification or standard.
Related standards are gathered in the Bibliography.

– 8 – IEC TR 61191-9:2023 © IEC 2023
PRINTED BOARD ASSEMBLIES –
Part 9: Electrochemical reliability and ionic contamination on
printed circuit board assemblies for use in automotive applications –
Best practices
1 Scope
This part of IEC 61191, which is a Technical Report, applies to electronic and electromechanical
automotive circuit board assemblies and describes current best practices for dealing with
electrochemical reactions like migration or corrosion and ionic contamination on the surface of
a circuit board as one failure mode under humidity load. This document deals with the evaluation
of materials and manufacturing processes for the manufacturing of electronic assemblies with
focus on their reliability under humidity loads. The electrical operation of a device in a humid
environment can trigger electrochemical reactions that can lead to short circuits and
malfunctions on the assembly. In this context, a large number of terms and methods are
mentioned, such as CAF (conductive anodic filament), anodic migration phenomena, dendrite
growth, cathodic migration, ROSE (resistivity of solvent extract), ionic contamination, SIR
(surface insulation resistance), impedance spectroscopy, etc., which are used and interpreted
differently. The aim of the document is to achieve a uniform use of language and to list the
possibilities and limitations of common measurement methods. The focus of the document is
on the error pattern of electrochemical migration on the surface of assemblies with cathodic
formation of dendrites.
Evaluation of different test methods of control units under high humidity load are not part of this
document.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60194-1, Printed boards design, manufacture and assembly – Vocabulary – Part 1:
Common usage in printed board and electronic assembly technologies
IEC 60194-2, Printed boards design, manufacture and assembly – Vocabulary – Part 2:
Common usage in electronic technologies as well as printed board and electronic assembly
technologies
3 Terms, definitions and abbreviated terms
For the purposes of this document, the terms and definitions given in IEC 60194-1, IEC 60194-2
and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp

3.1 Terms and definitions related to management
3.1.1
design authority
individual, organization, company, contractually designated authority, or agency responsible for
the design of electrical/electronic hardware, having the authority to define variations or
restrictions to the requirements of applicable standards, i.e., the originator/custodian of the
applicable design standard and the approved or controlled documentation
3.1.2
manufacturer
individual, organization, or company responsible for the assembly process and verification
operations
3.1.3
production part approval process
PPAP
procedure in accordance to IATF 16949 [1] to regulate the sample submission process within
the supply chain, primarily used for the series release of new parts
Note 1 to entry: The main objective of the procedure is the regulated start-up assurance with regard to quality and
quantity of mass production.
3.1.4
user
individual, organization, company, or agency responsible for the procurement of
electrical/electronic hardware and having the authority to define any variation or restrictions to
requirements
EXAMPLE Originator/custodian of the contract detailing the requirements.
3.2 Technical terms and definitions
3.2.1
conductive anodic filament
CAF
migration which occurs along the monofilament of reinforcing material such as glass cloth in an
inner layer part of a printed wiring board
3.2.2
no-clean
produced with a no-clean solder material and optimized process parameters throughout the
entire process chain (e.g. design, printing, soldering), for which flux residues are usually not
critical and removal of these residues is not necessary
Note 1 to entry: There could be additional requirements of customers.
3.2.3
resistivity of solvent extract
ROSE
analytical method to determine the integral contamination load on a CB or CBA causing
electrical conductivity
3.2.4
surface insulation resistance
SIR
electrical resistance of an insulating material between a pair of contacts, conductors or
grounding devices in various combinations, which is determined under specified environmental
and electrical conditions
– 10 – IEC TR 61191-9:2023 © IEC 2023
3.3 Abbreviated terms
AIT assembly and interconnect technology
AMP anodic migration phenomena
CB circuit board
CBA circuit board assembly
DI-water deionized water
ECM electrochemical migration
ECU electronic control unit (CBA with housing)
IC ion chromatography
ICont ionic contamination
iSn immersion tin
OSP organic surface protection
PB printed circuit board (bare board as delivered by PB manufacturer)
Note 1 to entry: This abbreviated term is not preferred.
PBA printed circuit board assembly (unit without housing)
Note 1 to entry: This abbreviated term is not preferred.
PCB printed circuit board (bare board as delivered by CB manufacturer)
Note 1 to entry: This abbreviated term is not preferred.
PCBA printed circuit board assembly (populated CB without housing)
Note 1 to entry: This abbreviated term is not preferred.
SMD surface mounted devices
SMT surface mounting technology
THR through hole reflow
THT through hole technology
WOA weak organic acid
4 Failure mode electrochemical migration
4.1 Background of electrochemical migration
The electrochemical migration on electronic assemblies is understood as the migration of
metallic ions such as Ag, Cu, Sn, Ni in a water film on the assembly. The ions are released at
the anode (the positive pole of the assembly, e.g. terminal 30), migrate by a diffusion controlled
mechanism in the water film to the cathode (the negative pole, e.g. ground, GND) and are
deposited there again by reduction with dendrite formation (electrocrystallisation). The dendrite
can then grow back towards the anode and create an electrical short circuit. This process can
only take place if there is a closed water film between the anode and cathode and if there is a
corresponding potential difference. The electrolysis of water always occurs as a reaction, so
that a local change in the pH value take place. This can trigger further reactions (e.g. hydrolysis
of materials or the formation of poorly soluble metal salts). The processes are shown in Figure 1.

Figure 1 – Principal reaction mechanism of ECM
The process of electrochemical migration itself is fast. Dendrite growth occurs within seconds
to a few minutes if a sufficiently thick (> 50 µm) water film (e.g. droplet formation by direct
condensation) is formed on the assembly. Thus, electrochemical migration is not an ageing
effect of materials, but is triggered by the event of direct condensation. Classical lifetime laws
cannot therefore be applied. With very thin closed water films (< 70 % rH with few molecular
layers, < 50 nm thickness), this process is significantly slowed down for molecular-structural
reasons.
Therefore, ECM is only found if a sufficient amount of water is present locally at a design
element having a potential difference (> 1,5 V). It is also visualized that small deviations in
material or processing properties can drastically change the criticality of the system concerning
ECM. The principal dependencies were presented on [2] (Figure 2). It illustrates very well the
problem that a failure prognosis based on widely used Peck or Lawson models regarding ECM
is not possible due to uncertainty of surface conditions and the fact that dewing events do not
follow an ageing law.
See [2].
Figure 2 – Uncertainty in local conditions determines ECM failures

___________
Numbers in square brackets refer to the Bibliography.

– 12 – IEC TR 61191-9:2023 © IEC 2023
The ECM error pattern can also occur with a time delay due to decomposition reactions or
diffusion processes. For example, ECM defects below a solder resist or within a conformal
coating only occur after sufficient saturation of the materials with water but are significantly
delayed by the slow diffusion processes within a polymer. Slow material decompositions (e.g.
hydrolysis of polymers by the local change of the pH-value) with an accompanying change of
their function (e.g. loss of the insulating effect of a solder resist) also belong to this group. In
these cases, ECM will only occur after extended periods of exposure to moisture (weeks to
months in high humidity tests). Those findings are illustrated in Figure 3. For degradation or
diffusion processes as rate determining step complex, models for failure prognosis could be
derived in contrast to the condensation case. However, those models are merely system specific
and cannot be transferred to different constructions and materials.

See [3]
NOTE Same failure mode but different reasons.
Figure 3 – Occurrence of ECM failures during humidity tests
In all tests and evaluations of assemblies operated in humid environment, it needs to be minded
that humidity can only be accelerated to a limited extent. An acceleration factor cannot be
derived in most cases. It needs always to be noted that the failure mechanism is not changed
by any test condition or acceleration approaches in a way that will not appear in the intended
end-use environment of the product. IEC 60068-3-4:2001 [4] already clearly emphasizes this
special feature for electrochemical failure mechanisms where humidity is necessary.
4.2 Complexity of electrochemical migration
The error pattern of electrochemical migration on assemblies is complex. Its occurrence
depends on various factors, which are shown in the VENN diagram (Figure 4). The attempt to
summarize the complex relationships in a single, easily accessible measured quantity, such as
only the reduction of ionic contamination, was therefore incorrect and is a frequent cause of
misinterpretations.
Figure 4 – VENN diagram showing the factors influencing ECM
In order to understand the error pattern of electrochemical migration in its totality, the 3 following
main influencing factors need to be analyzed and understood in more detail.
– Bias translated by voltage U and operation time t when U is applied as well as distances d
between metals with different potential, where the following relationship applies to the risk
of electrochemical migration P ≈ U × f(t) / d .
ECM
– Microclimate translated by local humidity (stress at design element) considering retarded
buildup of water path on circuit-board assemblies in a housing, heating-up and dry-out
effects, thermal mass of systems.
– Ionic contamination translated by materials properties considering processing, hygroscopic
behaviour, degradation of materials, chemical interactions.
For the complex system circuit-board assembly with a multitude of materials and interactions,
the measurement of the SIR value in the context of material characterizations as well as active
humidity testing of ECUs currently represents the most reliable method for evaluating the
electrochemical reliability of an assembly. The measurement of ionic contamination alone does
not provide any information about the reliability of an assembly in the intended end-user
environment. In 2017, IPC took this into account and eliminated a historical definition with a
limit of 1,56 µg/cm NaCl equivalent for cleaned assemblies in IPC-J-STD-001 [5] starting with
Amendment 1 to Rev G [6]. A more detailed background is given by the whitepaper IPC-WP-019
[7].
4.3 Conductive anodic filament (CAF) and anodic migration phenomena (AMP)
CAF and AMP belong to degradation mechanisms in CBs that are also triggered by
electrochemical processes. In both cases, dendrite-like structures occur, but unlike classical
dendrite growth, they propagate from the anode toward the cathode and consist of
semiconducting salts. In the CAF failure case, the electrochemical degradation mechanism
occurs preferentially along the glass fibre in the epoxy glass fibre composite of a printed circuit
board.
– 14 – IEC TR 61191-9:2023 © IEC 2023
In the AMP failure case, the electrochemical degradation mechanism occurs preferentially in
HV application in the bulk phase of polymers such as the solder mask. In both cases, these are
slow processes with material degradation that can be captured by classical lifetime model
approaches. Typical occurrence is shown in Figure 5. The mechanisms, analytical methods, or
derivation of lifetime laws for CAF and AMP are not discussed in detail in this document. Details
are given in [8] and [9].
a) CAF in base material b) AMP in solder mask
See [8]
Figure 5 – Occurrence of CAF and AMP
4.4 Creep corrosion
In addition to classical electrochemical migration with dendrite growth, another contamination-
related failure mechanism is creep corrosion (Figure 6). Creep corrosion primarily requires
susceptible metallization or final finishes. Ag is the most susceptible, followed by Cu and Ni. A
moisture film, well below the dewing point, is enough to trigger the slow corrosion mechanism.
A critical humidity is already reached at 60 % to 70 % rH. In addition, corrosive gases such as
nitrogen oxides (NO ), H S and CO tend to dissolve in the moisture film and promote water
x 2 2
adsorption by lowering the necessary so-called Gibbs energy. Contamination by atmospheric
pollutants such as SO or NO as well as sulfur-containing substances from flux residues,
x x
especially from natural doping of rosin, can cause creep corrosion. In very rare cases, halide
contamination from the manufacturing process of epoxy materials for CB fabrication also causes
creep corrosion of the base copper. Creep corrosion is a slow degradation mechanism that can
be captured by metal corrosion models. The mechanisms, analytical methods, or derivation of
lifetime laws for creep corrosion are not discussed in detail in this document. Details are given
in [10] [11] [12].
Figure 6 – Creep corrosion caused by corrosive gases
5 Electrochemical migration and relevance of ionic contamination
5.1 General aspects
The presence of free ions and also critical ions such as halides or WOA on an assembly can
increase the risk of electrochemical migration. On the other hand, the use of substances and
materials with technical quality and thus with certain ionic loads is typical for the industry, which
does not lead to ECM failures per se. The ionic contamination and its measurement method
need therefore to be considered in a differentiated way.
5.2 Background of ionic contamination measurement
In order to understand the importance of ionic contamination measurement and their limitations,
it is important to know their historical origin. This is described in detail in IPC-5703:2013 [13],
Chapter 7, and IPC-TP-1113 [14]. The methodology and conclusions date back to a time when
soldering was still done with rosin and ammonium chloride or ammonium bromide. Such
assemblies had to be washed to ensure that these highly corrosive substances were safely
removed. To monitor the cleaning results, these assemblies were rinsed again with an
isopropanol-water mixture after the washing process and the conductivity of this washing
solution was determined. In this context, the method ROSE (resistivity of solvent extract) was
developed. The conductivity of the solution is converted into a NaCl-equivalent: to this end, the
(hypothetical) amount of NaCl on the surface of the assembly, which, upon dissolving, would
result in the measured resistivity, is calculated. The measurement result, as expressed by the
NaCl equivalent does not indicate that NaCl is actually measured/present on the surface of the
assembly. The measured value rather represents the conductivity resulting from the multitude
of all ions that can be washed off an assembly by the selected solvent mixture. The correlation
to the electrochemical reliability of the assembly can be established by providing objective
evidence that a given assembly with a certain amount of soluble ionic contaminants on the
surface and with the given layout can be operated safely in a given end-use environment.
The ROSE method was then used as a standard method to check the cleaning process and
measurement results were tracked in control charts. Since this is a process control, the absolute
measurement values have limited significance and the ROSE method itself was never specified
exactly. Different solvent mixtures and analyzers are in use and this does not cause any issues
as long as the measuring conditions for a given product remain unchanged. The absolute
measurement ROSE values are not important as long as selected measurement conditions are
applied unchanged and only changes in the process are observed. Due to a series of

– 16 – IEC TR 61191-9:2023 © IEC 2023
unfortunate circumstances, however, a requirement of 1,56 µg/cm NaCl equivalent after a
cleaning process was included in military (e.g. MIL-STD-2000A [15]) and commercial (e.g.
IPC-J-STD-001 [5]) standards, However, this value was never correlated with the reliability of
assemblies in different end-user environment. In addition, more analysers came on the market
over time, local measurement methods for ionic contamination were developed and the method
of ion chromatography became more widely used, which led to repeated and controversial
discussions about absolute values of the different measurement methods. The IPC reacted to
this in 2017 and clarified that a single measurement value such as ROSE < 1,56 µg/cm is
obsolete and does not represent general product reliability (see [7]).
The processes for measuring ionic contamination by ROSE and ion chromatography are shown
schematically in Figure 7. The effects of the different extraction methods are highlighted. By
chance, ion chromatography has established itself as a worldwide, largely uniform procedure
with so-called "bag extraction" at 80 °C, for 1 h and a solvent mixture of
75 Vol % 2-propanol/25 Vol % DI-water. For measured values based on ion chromatography, a
certain comparability of numerical values is therefore possible. But also for a discussion about
absolute values based on ion chromatography, the correlation to reliability tests and field
experiences is necessary.
NOTE Measurement based on extraction as a first step followed by a measurement in the extract as second step
(see [16]).
Figure 7 – Ionic contamination measurement
The measuring methods for ionic contamination measurement are described in the following
documents.
– IPC-TM-650, method 2.3.25D [17], describes the ROSE measurement for CBs and CBAs;
the analysis requires the use of automatic ROSE testers. Solvent mixtures based on
75 Vol % 2-propanol/25 Vol % DI-water or 50 Vol % 2-propanol/50 Vol % DI-water are
allowed.
– IPC-TM-650, method 2.3.25.1, [18] describes the ROSE measurement only for CBs; the
analysis can be done by bag-extraction and conductivity measurement, but also by
automatic ROSE testers. Only the solvent mixture of 75 Vol % 2-propanol/25 Vol % DI-water
is allowed.
– IPC-TM-650, method 2.3.26A [19] and method 2.3.26.1A [20], originally described the static
and dynamic ROSE measurement methods respectively. These measurement methods will
be no longer be referenced, as their contents have now been incorporated into IPC-TM 650,
2.3.25D [17].
– IPC-TM-650, method 2.3.28B, [21] describes the measurement by ion chromatography and
lists 21 species to be measured. Preferably, the bag-extraction is carried out with 75 Vol %

2-propanol/25 Vol % DI-water at 80 °C and 1 h extraction time. Deviations from these
conditions are allowed, but only if agreed between user and manufacturer.
– IPC-TM-650, method 2.3.28.2, [22] describes the measurement by ion chromatography and
lists 17 species to be measured. The bag-extraction is fixed at 80 °C for 1 h, but only allows
the use of the solvent mixture 10 Vol % 2-propanol/90 Vol % DI-water. This measuring
method will no longer be referenced, the contents of which have now been included in
IPC-TM-650, 2.3.28B [21].
In order to overcome the historic misunderstandings about the cleanliness of assemblies and
the associated term ROSE, the IEC produced IEC 61189-5-504:2020 [23], in which the term
ROSE was replaced by PICT. PICT stands for "process ionic contamination testing" to make
the original purpose of the ROSE measurement method clearer. IEC 61189-5-504
...