IEC 61190 1 3 Edition 2 1 2010 11 INTERNATIONAL STANDARD NORME INTERNATIONALE Attachment materials for electronic assembly – Part 1 3 Requirements for electronic grade solder alloys and fluxed and non[.]
Alloy composition
This standard covers solder alloys listed in Tables B.1, B.2, and B.3, including pure tin and pure indium Each alloy is designated by an alphanumeric name that indicates the component elements by their chemical symbols and nominal mass percentages, ending with a variation letter (A, B, C, D) Additionally, alloys have a short name that combines the chemical symbol of the key element, its nominal percentage, and the variation letter.
Tables B.1, B.2, and B.3 detail the composition, short names, and temperature characteristics of various alloys Table B.4 provides a cross-reference of solidus and liquidus temperatures with their corresponding alloy names, while Table B.5 links ISO alloy numbers and designations from ISO 9453 to the respective alloy names.
NOTE The alloy short name can be used as identifier of solder alloy(s) in mounted boards used in electrical and electronic equipment (see Annex C).
Solder form
Table 1 shows the forms of solder materials covered by this standard listed with their single-letter designating symbols
Flux type
The flux types used in/on solders covered by this standard are listed in Table 2 The requirements for fluxes are covered by IEC 61190-1-1
Table 2 – Flux types and designating symbols
Flux activity levels wt % halide b
(inorganic ISO flux is different)
High (>2.0) H1 INH1 fluxes are available in solid (S), paste/cream (P), or liquid (L) forms For comparisons of RO, RE, OR, and IN composition classes, as well as L, M, and H activity levels with traditional classes like R, RMA, RA, water-soluble, and low solids "no-clean," refer to sections 7.1 and 7.2 of IEC 61190-1-1 The numbers 0 and 1 indicate the absence and presence of halides, respectively; further details can be found in section 4.2.3 of IEC 61190-1-1 regarding L, M, and H nomenclature ISO designations are similar to IEC designators, with minor differences in characteristics.
Flux percentage and metal content
The flux percentage in solid-form solder products, indicated by a single alphanumeric character as per Table 3, represents the nominal mass percentage of flux Additionally, "metal content" denotes the percentage of metal present in solder paste, as defined in IEC 61190-1-2.
Design symbol Nominal Allowable range
Other characteristics
Standard bar solders are categorized based on their unit mass, while wire solders are classified by their wire size (outside diameter) and unit mass Ribbon solders are differentiated by their thickness, width, and unit mass, and powder solders are classified according to their powder particle size distribution and unit mass.
Materials
Materials must be selected to ensure that the solder product meets the specified requirements The use of recovered or recycled materials is encouraged, provided they conform to or exceed the standards of virgin raw materials.
Alloys
The solder alloy must conform to the specifications outlined in Annex B, which includes electronic grade solder alloys listed in Tables B.1, B.2, and B.3, such as pure tin (Sn99) and pure indium (In99) The elements specified in these tables are the essential components of the alloy, while any other elements are considered impurities It is crucial that the solder alloy, including solder powder, is a homogeneous mixture of these component elements, ensuring that each particle is uniform Additionally, unless stated otherwise, the percentage by mass of impurity elements in alloys marked with an “A” or “B” must be carefully controlled.
“C” suffix shall not exceed the following values and the values listed in 5.2.1, 5.2.2, and
5.2.3 respectively, and the percentage by mass of impurity elements in alloys which are identified with a “D” suffix shall conform to the requirements in 5.2.4
Ag: 0,05 Au: 0,05 Cu: 0,05 Ni: 0,01 Sn: 0,25
Al: 0,001 Bi: 0,10 Fe: 0,02 Pb: 0,10 Zn: 0,001
The percentage of each element in an alloy shall be determined by any standard analytical procedure Wet chemistry shall be used as the referee procedure
In alloys which are identified with an “A” suffix, the percentage by mass of antimony (Sb) as an impurity element shall not exceed 0,50
In alloys which are identified with a “B” suffix, the percentage by mass of antimony as an impurity element shall not exceed 0,20
In alloys which are identified with a “C” suffix, the percentage by mass of antimony as an impurity element shall not exceed 0,05
Alloys marked with a “D” suffix are ultra-pure and designed for barrier-free die attachment applications In these alloys, the total mass percentage of all impurity elements must not exceed 0.05%, and specific sets of impurity elements are also subject to strict limits.
Set 1: Be, Hg, Mg, and Zn Set 2: As, Bi, P, and Sb.
Solder forms
This standard addresses various forms of solders, including bars, wires, ribbons, powders, and special solders Typically, bar solders and solder powders are non-fluxed, while wire, ribbon, and special solders can be non-fluxed, flux-cored, flux-coated, or a combination of both Users are encouraged to identify the available standard solder form characteristics from potential sources and to specify these characteristics as thoroughly as possible.
The nominal cross-section area, length, and mass must adhere to specified values The actual cross-section area should not deviate from the nominal value by more than 50%, while the actual length and mass should not vary by more than 20% and 10%, respectively Additionally, bars featuring special end configurations, like hooks or eyes, are categorized as special solders.
The wire size, flux type, and flux percentage shall be as specified (see Clause A.2 e))
Wire solders must have a circular cross-section, with the wire size reflecting the nominal outside diameter The actual outside diameter should not deviate from the nominal diameter by more than ±5% or ±0.05 mm, whichever is greater.
The ribbon thickness and width, flux type, and flux percentage shall be as specified (see
Clause A.2 g) states that unless specified otherwise in Clause A.2 h), ribbon solders must have a rectangular cross-section, with actual thickness and width not deviating from nominal values by more than ±5% or ±0.05 mm, whichever is greater.
The powder size and shape shall be as specified (see Clauses A.2 i)) and A.2 j)) The characteristics of six standard solder powders, sizes 1 through 6, are listed in Table 4
Solder powder must be spherical in shape when not otherwise specified It should be smooth, bright, and as free as possible from adhering small particles and oxides.
Solder powders composed of high-lead alloys are inherently not "bright," yet they should not exhibit an excessively dark appearance Additionally, solder powders that consist of multiple alloys are categorized as special solders.
Percentages of powder by mass
Less than 1 % larger than mm
Maximum particle size shall be determined in accordance with IEC 61189-6, Test method
6X04 Powder particle size distribution shall be determined in accordance with IEC 61189-6,
The shape of solder powder should be assessed through visual observation using a binocular microscope with adequate magnification, the light beam scatter method, or an appropriate microscopic imaging analysis technique It is essential that solder powders are visually confirmed to possess a minimum standard.
Ninety percent of particles with a length-to-width ratio of 1:2 or less are classified as spherical powders Solder powders that exhibit a light beam scatter deviation or image analysis results consistent with these visual criteria are also categorized as spherical powders Any powders that do not meet these specifications are classified as non-spherical.
All pertinent characteristics and tolerances for special form solders shall be specified (see
Clause A.2 k) defines special solders as those that do not completely fit into any other solder classification specified in this document or in IEC 61190-1-2 Examples of special solders include anodes, bars with hook or eye ends, chips, ingots, multiple-alloy powders, pellets, preforms, rings, and sleeves.
Flux type and form
The type and form of flux must adhere to the specifications outlined in Clause A.2 l) Fluxes utilized in the production of solder products must comply with IEC 61190-1-1 standards These fluxes should be thoroughly tested and characterized according to IEC 61190-1-1, with no alterations made post-testing, except for the inclusion of inert plasticizers.
The mass percentage of flux in solders must adhere to the specifications outlined in Clause A.2 m) For fluxed solders, excluding solder paste, the flux percentage is determined based on established guidelines.
Table 3 The flux percentage of flux-coated and/or flux-cored solder shall be determined in accordance with IEC 61189-6, Test method 6C09
Flux-cored solders must have cores that are continuous, uniform in cross-section, and symmetrically arranged, unless specified otherwise It is important to seal the cores at both ends to prevent any leakage of flux.
Coatings on flux-coated solders must be dry and tack-free to prevent individual pieces from sticking together, provided that the temperature does not exceed 25 °C and the relative humidity remains at or below 60%.
Flux residue dryness
When specified (see Clause A.2 p)), the dryness characteristics of the reflowed residue of fluxed solders shall be determined in accordance with IEC 61189-5, Test method 5X12
When a fluxed solder is tested in accordance with Test method 5X12, the flux residue of
“no-clean” solders and, when specified, other flux type solders, shall be free of tackiness
Spitting
When specified (see Clause A.2q)), the spitting characteristics of flux-cored wire and ribbon solders shall be determined in accordance with IEC 61189-5, Test method 5X13.
Solder pool
The characteristics of fluxed solder in the solder pool must be determined according to IEC 61189-5, Test method 5X14, as specified in Clause A.2 r) During testing, the flux should facilitate the even spreading of molten solder over the coupon, creating a uniform coat that tapers to a thin edge There should be no signs of dewetting or nonwetting, and no spattering should be present, which is indicated by flux or flux residue particles outside the main residue pool Additionally, irregularly shaped solder pools do not automatically signify dewetting or nonwetting.
Labelling for product identification
Unless otherwise specified (see Clause A.2 s)), solder bars shall be marked with the alloy name or alloy short name and the manufacturer's name or commonly accepted symbol
All spools, packages, and containers of wire, ribbon, and powder solders, along with accompanying documentation for bar and special solders, must be clearly marked with essential information This includes the manufacturer's name and address, the standard's number and revision, a description of the solder product along with the manufacturer's designation, the net mass of the solder, batch numbers, and manufacturing dates Additionally, the expected useful life of the solder product should be indicated if applicable, along with all relevant health and safety markings, such as lead-free or lead-containing labels Any other pertinent information related to the specific solder form and any additional markings specified in the contract or purchase order must also be included.
Workmanship
Solder products shall be made uniform in quality and free from defects which limit service life or affect the serviceability or appearance
Responsibility for inspection and compliance
The user shall specify the qualification and quality conformance inspections (see Clause
The manufacturer of solder products is accountable for conducting qualification and quality conformance inspections They have the option to utilize their own facilities or any other approved facility for these inspections, provided that the chosen facility is not disapproved by the user.
Manufacturers must ensure that all solder products or supplies provided to users meet the specifications outlined in the contract or purchase order, as well as Clause 5 The lack of inspection requirements does not exempt the vendor from this obligation.
Materials specified must fulfill all requirements outlined in Clause 5 Inspections, apart from the performance inspections detailed in this specification, will be integrated into the contractor's overall inspection system or quality program The vendor is responsible for ensuring that all products or supplies submitted for acceptance meet the purchase order contract requirements.
A quality assurance program for materials provided under this specification must be established and maintained in accordance with ISO 9001, or as mutually agreed upon by the user and manufacturer, and will be monitored by the qualifying activity.
6.1.2 Test equipment and inspection facilities
Suppliers must establish and maintain test and measuring equipment, along with inspection facilities, that meet the necessary accuracy, quality, and quantity for required inspections Additionally, a calibration system must be implemented to ensure the accuracy of the measuring and testing equipment, adhering to the general requirements outlined in IEC 61189-5 and IEC 61189-6.
Unless otherwise specified, all inspections shall be performed in accordance with the test conditions specified in Clause 5.
Classification of inspections
The inspections specified in this standard are classified as follows: a) materials inspection (6.3); b) qualification inspection (6.4); c) quality conformance (6.5)
Figures 1 to 4 are recommended for documenting the results of inspections for alloy and solid form solders Definitive results should be recorded on the report forms when applicable, while successful inspections can be indicated with check marks when definitive results are not necessary.
Test report on solder alloy (for suffix A, B, and C alloys)
Enter appropriate information in top portion and requirements columns of report and complete report by entering the test results or checkmarks in the appropriate spaces
Date inspection completed: _ Overall results 1 : _Pass _Fail
Inspection performed by: _ Witnessed by _
Percentage in sample Pass/Fail 2 Tested by and date
1 Overall results: Check "Pass" if the test results for all elements conform to the requirements, otherwise check
2 Pass/Fail: Enter "P" for an element if test results conform to the actual requirement, otherwise, enter "F."
3 W hen antimony (Sb) is an impurity in the alloy being tested, check the appropriate Sb percentage requirement in column 3
Figure 1 – Report form for solder alloy tests
Test report on solder powder
Enter appropriate information in top portion and requirements columns of report and complete report by entering the test results or checkmarks in the appropriate spaces
Alloy designation: Powder size number _
Date inspection completed: _ Overall results 1 : _Pass _Fail
Inspection performed by: _ Witnessed by _
Inspections Requirements Test results obtained
Pass/fail 2 Tested by and date
< 1 % larger than _ mm ³ 80 % between _ - _ mm ³ 90 % between _ - _ mm
1 Overall results: Check "Pass" if the test results for all elements conform to the requirements, otherwise check
2 Pass/Fail: Enter "P" for an element if test results conform to the actual requirement, otherwise, enter "F."
Figure 2 – Report form for solder powder tests
Test report on non-fluxed solder
Enter appropriate information in top portion and requirements columns of report and complete report by entering the test results or checkmarks in the appropriate spaces
Quality conformance A Manufacturer's batch number: _
Quality conformance B Date of manufacture:
Shelf-life extension Original USE-BY date: _
Performance Revised USE-BY date: _
Date inspection completed: _ Overall results 1 : _Pass _Fail
Inspection performed by: _ Witnessed by _
Inspections Requirements Test results obtained
Pass/Fail 2 Tested by and date Material
1 Overall results: Check "Pass" if the test results for all elements conform to the requirements, otherwise check
2 Pass/Fail: Enter "P" for an element if test results conform to the actual requirement, otherwise, enter "F."
Figure 3 – Report form for non-fluxed solder tests
Test report on fluxed wire/ribbon solder
Enter appropriate information in top portion and requirements columns of report and complete report by entering the test results or checkmarks in the appropriate spaces
Quality conformance A Manufacturer's batch number: _
Quality conformance B Date of manufacture:
Shelf-life extension Original USE-BY date: _
Performance Revised USE-BY date: _
Date inspection completed: _ Overall Results 1 : _Pass _Fail
Inspection performed by: _ Witnessed by _
Inspections Requirements Test results obtained
Pass/Fail 2 Tested by and date Material
1 Overall results: Check "Pass" if the test results for all elements conform to the requirements, otherwise check
2 Pass/Fail: Enter "P" for an element if test results conform to the actual requirement, otherwise, enter "F."
Figure 4 – Report form for fluxed wire/ribbon solder tests
Materials inspection
Materials inspection must include certifications and supporting data to ensure that the materials used in solder product manufacturing comply with relevant specifications and standards before use Additionally, certifications and verifying data related to qualification test samples should be incorporated into the qualification test report.
Qualification inspections
Qualification inspections involve testing materials, processes, and products to ensure that a manufacturing facility possesses the required capabilities to produce acceptable solder products Users are advised to leverage documented results from prior product inspections conducted by the facility, rather than insisting on new qualification inspections, to assess the facility's acceptability as a source for solder products.
Solder product samples, created with the same materials, equipment, processes, and procedures as those used in production, must undergo the qualification inspections outlined in Clause A.2 t) The standard qualification inspections for these solder products are detailed in Table 5, unless stated otherwise.
Clause A.2 u)), the qualification inspections shall be conducted using the procedures specified in 6.5
Sample size should be appropriate for the solder being inspected and the inspection being performed
The sample shall be subjected to the inspection specified in Table 5
Quality conformance
The material manufacturer shall perform those inspections necessary to insure that the process is in control and to insure that the product is within specification limit
The material shall be subjected to the inspections specified in Table 5
Statistical sampling and inspection shall be in accordance with an agreed to (between user and supplier) quality programme (see 6.1.1)
If an inspection lot is rejected, the supplier has the option to either rework the defects or remove the defective units and submit the lot for re-inspection Re-submitted lots will undergo tightened inspection and must be distinctly separated from new lots, clearly labeled as re-inspected lots.
Preparation of solder alloy for test
Remove five pieces of flux-cored wire and ribbon solder, each about 50 mm long, at intervals of approximately 0.5 m from each spool or cut length Visually inspect both ends of each piece using magnification if necessary, checking for dimensional uniformity, core continuity, homogeneity, and overall condition.
6.6.1.1 Wire solder up to approximately 6 mm diameter
To achieve clean breaks in wire solder, hold it under tension with the desired separation point positioned over a luminous flame, like that from a match This method causes the solder to snap apart at the hot shortness, revealing the shapes of the flux core and ensuring continuity of the flux.
NOTE This method of solder separation should be tried on small diameter wire solders to see if it will work satisfactorily before using the method in 6.6.1.2
6.6.1.2 Ribbon solder and wire solder larger than 6 mm diameter
Using a very sharp cutting edge, such as a strong razor blade, carefully cut the solder making special efforts to minimize the distortion in the solder by the cutting force
7 Preparation for delivery – Preservation, packing and packaging
The preservation, packing, packaging, and exterior marking of soldering products must meet or exceed the supplier's standard commercial practices, unless the contract or purchase order states otherwise.
Selection of various alloys and fluxes for use in electronic soldering –
This annex contains information of a general or explanatory nature that may be helpful, but is not mandatory, for the application of this standard
This standard covers alloys designed for consumer, industrial, and commercial electronic soldering applications, including those used in government electronic hardware It is essential to consider various alloys and fluxes for electronic soldering, and users are encouraged to seek guidance from application experts at solder manufacturing companies for comprehensive information on alloy and flux selection and usage.
Tin-lead solder alloys, especially eutectic and near-eutectic types, are essential for creating solder connections in hardware assemblies and various general-purpose soldering tasks A wide variety of these alloys is available to meet the diverse needs of electronic soldering, including lead tinning and multiple-pass hardware assembly.
Recent findings indicate that the addition of antimony (0.2% to 0.5%) to tin-based electronic solder alloys, previously used to prevent "tin pest," is no longer necessary Tin pest, which occurs when ultra-pure tin transforms into a white powder at low temperatures, is not a concern when tin is mixed with 0.2% of nearly any other metallic element Consequently, the minimum requirement for antimony in tin-lead solder alloys has been removed, eliminating an unnecessary cost However, in alloys containing silver, it is essential to maintain a reduced level of antimony to prevent the rapid formation of antimony-silver intermetallics, which can diminish the advantageous effects of silver.
Bismuth is used in soldering alloys to achieve ultra-low soldering temperatures Bismuth alloys generally exhibit poor wetting characteristics and have high dielectric properties
Cadmium alloys are useful for electromagnetic shielding Because of possible carcinogenic effects of cadmium, appropriate measures for personal safety should be used when soldering with alloys containing cadmium
Copper is added to tin-lead alloys to reduce tip degradation on soldering irons used in hand soldering operations
Ultra-high purity gold alloys are essential for barrier-free and die-attachment applications, while standard gold alloys offer significant benefits in high-reliability hybrid assemblies, particularly in systems operating at microwave frequencies.
Indium-based soldering alloys provide some advantages when soldering to gold coatings as long as the soldering temperature of 120 °C is not to be exceeded for long periods of time
In environments with high temperature, humidity, or salt spray, indium-based soldering alloys should only be used if hermetically sealed or conformally coated These alloys outperform standard tin-lead solders for assemblies operating at microwave frequencies.
Users are cautioned concerning the use of high percentage indium solders with copper because of the formation of excessive intermetallic compounds
Silver-tin, silver-lead, and tin-lead-silver alloys are commonly utilized for soldering silver-plated components, effectively preventing silver leaching during the soldering process Additionally, the incorporation of silver with tin and lead enhances the temperature properties and increases the hardness of the solder.
A.1.1.8 Tin-silver-copper-antimony alloys
The tin-silver-copper-antimony alloy, while mainly a non-electronic alloy, has gained attention as some electronic equipment manufacturers adopt it to meet "lead-free" soldering standards.
Acquisition documents must clearly outline essential specifications, including the standard's number, revision, title, and date, as well as the alloy designation They should detail the nominal cross-section, length, and unit mass of bar solder, along with any tolerances for these dimensions Additionally, the documents need to specify the wire size, flux type, and percentage for wire solder, including any diameter tolerances For ribbon solder, the thickness, width, flux type, and percentage must be included, along with any relevant tolerances Furthermore, the standard powder size number or characteristics of non-standard powder, as well as the powder shape, should be documented Lastly, a comprehensive description of the characteristics of any special form soldering products being acquired is required.
The article outlines several critical components related to flux and soldering processes It includes details on flux type and percentage, as well as core requirements and conditions for coatings Additionally, it addresses necessary tests such as the flux residue dryness test, spitting test, and solder pool test Marking requirements and qualification inspections are also highlighted, along with their respective procedures Finally, it emphasizes the importance of preservation, packing, packaging, and exterior marking requirements.
Buyers are encouraged to reach out to potential suppliers to identify available standard packaging sizes and materials, while also specifying standard items whenever possible In cases where non-standard items are required, it is advisable for buyers to consult with suppliers to find the most cost-effective configurations that meet their needs.
Wire solders are generally available in wire sizes (outside diameters) of 0,25 mm to
Ribbon solders typically come in thicknesses ranging from 0.76 mm to 2.5 mm and widths up to 50 mm They are usually supplied on spools or cards with unit masses of 0.25 kg, 0.5 kg, 1 kg, 2 kg, 5 kg, and 10 kg, while larger bulk packaging options are also available from most manufacturers.
Bar solders are generally long and slender and are usually used to replenish solder baths
The nominal unit masses for Sn63Pb37 and similar solder alloys are 1 kg, 2 kg, 5 kg, and
The mass of bar solders can vary significantly, typically around 10 kg, due to differences in density among various solder alloys, such as high lead and low lead, as well as variations in forming processes like vertical molding, flat molding, and extruding However, the actual mass of a bar made from a specific alloy and unit mass should not differ by more than 10% from that of another bar of the same alloy and unit mass.
Solder powders are generally made to order and can be packaged in a variety of packages and unit masses
A.4 Protocol for establishing short names for IEC 61190-1-3 alloys
A.4.1 Lead containing solder alloys and specialty alloy (see Tables B.2 and B.3)