WG 2 - TC 91/WG 2

IEC TR 61191-9:2023, 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.

IEC PAS 61191-10:2022(E) provides guidelines which deal with the requirements for the protective coating,
its properties, as well as the application of liquid coating materials for electronic assemblies. These guidelines help control in practice the application of protective coatings from the layout to the functional test of the assembly after coating.

IEC TR 61191-8:2021(E) gives guidelines for dealing with voiding in surface-mount solder joints of printed board assemblies for use in automotive electronics. This technical report focuses exclusively on voids in solder joints connecting packaged electronic or electromechanical components with printed boards (PBs). Voids in other solder joints (e.g. in a joint between a silicon die and a substrate within an electronic component, solder joints of through-hole components, etc.) are not considered. The technical background for the occurrence of voids in solder joints, the potential impact of voiding on printed board assembly reliability and functionality, the investigation of voiding levels in sample- and series-production by use of X‑ray inspection as well as typical voiding levels in different types of solder joints are discussed. Recommendations for the control of voiding in series production are also given. Annex A collects typical voiding levels of components and recommendations for acceptability.

IEC 61191-1:2018 is also available as IEC 61191-1:2018 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 61191-1:2018 prescribes requirements for materials, methods and verification criteria for producing quality soldered interconnections and assemblies using surface mount and related assembly technologies. This part of IEC 61191 also includes recommendations for good manufacturing processes. This edition includes the following significant technical changes with respect to the previous edition:
- the requirements have been updated to be compliant with the acceptance criteria in IPC‑A-610F;
- the term "assembly drawing" has been changed to "assembly documentation" throughout;
- references to IEC standards have been corrected;
- Clause 9 was completely rewritten;
- Annex B was removed because there are already procedures for circuit board assemblies.

IEC 61190-1-3:2017 prescribes the requirements and test methods for electronic grade solder alloys, for fluxed and non-fluxed bar, ribbon, powder solders and solder paste, for electronic soldering applications and for "special" electronic grade solders. For the generic specifications of solder alloys and fluxes, see ISO 9453. This document is a quality control document and is not intended to relate directly to the material's performance in the manufacturing process.
This edition includes the following significant technical changes with respect to the previous edition:
a) The maximum impurity level of Pb has been revised and the table of lead free solder alloys includes some additional lead free solder alloys.

IEC 61191-4:2017 prescribes requirements for terminal soldered assemblies. The requirements pertain to those assemblies that are entirely terminal/wire interconnecting structures or to the terminal/wire portions of those assemblies that include other related technologies (i.e. surface mounting, through-hole mounting, chip mounting).
This edition includes the following significant technical changes with respect to the previous edition:
The requirements have been updated to be compliant with the acceptance criteria in IPC‑A-610F.

IEC 61191-3:2017 prescribes requirements for lead and hole solder assemblies. The requirements pertain to those assemblies that totally use through-hole mounting technology (THT), or the THT portions of those assemblies that include other related technologies (i.e.. surface mount, chip mounting, terminal mounting).
This edition includes the following significant technical changes with respect to the previous edition:
a) The requirements have been updated to be compliant wit the acceptance criteria in IPC-A-610F.

IEC 61191-2:2017 gives the requirements for surface mount solder connections. The requirements pertain to those assemblies that are totally surface mounted or to the surface mounted portions of those assemblies that include other related technologies (e.g. through-hole, chip mounting, terminal mounting, etc.).
This edition includes the following significant technical changes with respect to the previous edition:
a) the requirements have been updated to be compliant with the acceptance criteria in IPC‑A-610F;
b) some of the terminology used in the document has been updated;
c) references to IEC standards have been corrected;
d) five termination styles have been added.
The contents of the corrigendum of September 2019 have been included in this copy.

IEC 61190-1-2:2014-02(en-fr) specifies general requirements for the characterization and testing of solder pastes used to make high-quality electronic interconnections in electronics assembly. This standard serves as a quality control document and is not intended to relate directly to the material's performance in the manufacturing process. This edition includes the following significant technical changes with respect to the previous edition:
a) modification of the solder powder size in Table 2;
b) addition of the information of "Reflow condition and profile" in Annex B;
c) addition of a new Annex C.

IEC 61191-2:2013 gives the requirements for surface mount solder connections. The requirements pertain to those assemblies that are totally surface mounted or to the surface mounted portions of those assemblies that include other related technologies (e.g. through-hole, chip mounting, terminal mounting, etc.). This edition includes the following significant technical changes with respect to the previous edition:
- IPC-A-610 on workmanship has been included as a normative reference;
- some of the terminology used in the document has been updated;
- references to IEC standards have been corrected;
- the use of lead-free solder paste and plating are addressed.

IEC 61191-1:2013 prescribes requirements for materials, methods and verification criteria for producing quality soldered interconnections and assemblies using surface mount and related assembly technologies. It also includes recommendations for good manufacturing processes. This edition includes the following significant technical changes with respect to the previous edition:
- reference standard IEC 61192-1 has been replaced by IPC-A-610;
- some of the terminology has been updated;
- references to IEC standards have been corrected;
- the use of lead-free alloys in the assembly have been added.

IEC 61191-6:2010 specifies the evaluation criteria for voids on the scale of the thermal cycle life, and the measurement method of voids using X-ray observation. This part of IEC 61191 is applicable to the voids generated in the solder joints of BGA and LGA soldered on a board. This part of IEC 61191 is not applicable to the BGA package itself before it is assembled on a board. This standard is applicable also to devices having joints made by melt and re-solidification, such as flip chip devices and multi-chip modules, in addition to BGA and LGA. This standard is not applicable to joints with under-fill between a device and a board, or to solder joints within a device package. This standard is applicable to macrovoids of the sizes of from 10 µm to several hundred micrometres generated in a soldered joint, but is not applicable to smaller voids (typically, planar microvoids) with a size of smaller than 10 µm in diameter. This standard is intended for evaluation purposes and is applicable to research studies, off-line production process control and reliability assessment of assembly.

Specifies general requirements for the classification and testing of soldering fluxes for high-quality interconnections in electronics assembly. This standard is a flux characterization, quality control, and procurement document for solder flux and flux containing material in electronics assembly technology.

Defines methods of registration and analysis of defects on soldered printed board assemblies. These methods are described to allow effective comparison of performance between products, processes and production locations, and can serve as a basis for general quality improvement.