PCB Blog - The impact of lead-free regulations on PCB boards

The impact of lead-free regulatory development on PCB boardassembly, Lead-containing solder and lead alloy surface mount technology (SMT) have been widely used in electronic product manufacturing technology for a long time, especially Sn-Pb eutectic solder, with its ease of use, stable solderability, and price. As a practical low-temperature alloy, at the same time, it has unique properties (such as: low melting point, good ductility, good fatigue resistance, high thermal cycle, good electrical conductivity, high bonding), which is very suitable for electronic products. In the current high-density electronic industry assembly process, it has been playing a suitable and widely used role. Lead-based solder has three functions in electronic connections: (1) to complete the surface treatment of the printed circuit board, (2) to coat the surface of the part to provide a solderable surface, (3) to solder the electronic part to the printed circuit board. Although many PCB board manufacturers are producing PWB surface treatment actions, using new alternatives such as organic soldering materials (OSPs) to replace lead-containing solder, lead solder still dominates the lead treatment and continues to be the main solder option. Now, due to the generalization and convenience of electronic products, a large number of electronic products are used in the household or consumer market. As for the end-of-life of the product, whether it is buried or incinerated as the end-of-life When the final ingredients are returned to the environment through environmental media, they will cause irreparable lead pollution, which will cause great harm to the earth's environment and human survival.

Regulatory and Specification Requirements
Many regulations currently in effect or under review have a significant impact on "lead-free electronics". Therefore, the definition of "lead-free" for these regulations and their related requirements has become a requirement that we must understand. In U.S. water pipe solders and fluxes, lead content below 0.2% is considered lead-free. In Europe, the standard recognized by ISO is 0.1%; the standard recognized by the EU End of Life and Hazardous Substances Prohibition Directive is 0.1%; however, there is still no lead-free definition for electronic assembly.

US regulations
Relevant legislative activities in various states in the United States: Although there is no known state requiring lead-free, some states are indeed beginning to engage in the recycling of electronic products because they have recognized the long-term environmental hazards of electronic product materials. The Electronic Recycling Directive (ERI) provides an ongoing view of activities at the state and national level.

Japanese regulations
There are currently no pending domestic regulations specifically calling for the ban on lead. In any case, the Japanese Ministry of Trade proposed recycling legislation in May 1998; the Japanese EPA and the government recommended reducing the use of lead to facilitate continued increasing recycling. In Japan's Residential Electronics Recycling Law, which was renovated in 1998, OEMs were required to prepare for the collection and recycling of four major products before April 1, 2001. While this law does not address the use of lead-containing products, there is another regulation that prohibits companies from letting toxic waste flow into the environment.

EU regulations
WEEE/RoHS: Due to increasing pressure from countries within the EU, the EC found it necessary to draft legislation to control toxic elements in electronic equipment. The newly developed "Waste Electrical and Electronic Equipment (WEEE) Directive and Restriction of Hazardous Substances (RoHS) Directive" (2002/10) received considerable response from the electronics industry. In addition to the responsibility for recycling and reusing after the exists in the product. Packing & Packing Directive: In 1994, it was proposed to standardize the content of lead, cadmium, mercury, chromium (hexavalent; Cr+6), and polyvinyl chloride (PVC) in product packaging substances (inner packaging, outer packaging, and transportation packaging), such as 2001 By the end of the year, the total content of the above metal restricted substances shall not exceed 100ppm (including cadmium shall not be higher than 5ppm). End-of-life Vehicle: In addition to specifying the responsibility for recycling and reuse of automotive products after the end of their life, the directive also regulates the content of lead, cadmium, mercury, chromium, and polyvinyl chloride to limit their presence in products. The quality control operation of Lead-Free PCB Assembly.

Purpose
Provides compliance for suppliers to convert products to lead-free/hazardous substance prohibition; just as process and product reliability require lead-free solder, hazardous substance compliance also includes material compliance.

Process
(1) As in JESD46-B, compliance with all changes to existing parts to lead-free/hazardous substance prohibitions shall be documented by the manufacturer in a PCN-issued manner; any part changes are subject to compliance with lead-free/hazardous substance prohibitions Should be considered for significant changes.
(2) As in JESD48-A, the discontinuation of all existing parts shall be notified to the client.
(3) All manufacturers are required to provide notification when they are going to produce lead-free/hazardous substances prohibited compliant products, and should provide customers with a technical roadmap of the product to indicate planned changes and implementation schedules; feasibility and product Recent developments in life cycle information, and compliant products for lead-free/hazardous substance prohibition should be specified in detail.

Compatibility and Testing
A packaged lead-free part quality approval shall include:
(1) Manual, package, transport, use (IPC J-STD-033A)
(2) Solderability test (IPC/EIA J-STD-002 version) does not require cleaning and water-washing solder paste and wave soldering flux should be included
(3) Reliability test for all solders (IPC-A-9701)
(4) Mechanical shock and vibration test (AEC-Q100-Rev E/Mil-Std 883)
(5) High temperature storage (AEC-Q100-Rev E/JESD22-A103-A)
(6) Tin whisker growth test (Reference: NEMI Tin Whiskers Growth Tests, Rev. 4.5)
(7) Moisture sensitive layer test MSL testing: the layer that the moisture sensitive layer of the part should not exceed. In any case, the feasible test should include the comparison between the old and new parts. The moisture sensitive layer test should be based on IPC/JEDEC J-STD- 020 (version)

Parts Confirmation
(1) All parts should have external packaging boxes and internal packaging materials (discs, tubes, rolling strips), and be marked with lead-free/hazardous substance prohibition traceability information, which should be displayed on the packaging of the parts at the same time .
(2) All lead-free/hazardous substances prohibited parts should have the sign-off of the new supplier's P/N, and it is acceptable to be attached to the front or back of the existing P/N structure.
(3) The data page of the component should clearly indicate the composition of the terminal solder, the temperature value of the part, the temperature limit recommended and the reflow profile, and the humidity sensitivity value. If there is no data page with this information, there should be a clear reference where to find out .
(4) Standard JEDEC JESD97 for the identification of lead-free/hazardous substance-prohibited products and product labeling standards.

Compliance
(1) Verification of "Hazardous Substance Prohibition Compliance" requires the generation and submission of documents to confirm the method and result, which takes precedence over the shipment of hazardous substance prohibited compliance parts.
(2) The verification batch characteristic form of "Hazardous Substance Prohibition Compliance" shall be presented in the delivery batch of each hazardous substance prohibited compliant part.
(3) The verification must be handled in accordance with the "Material Composition Declaration Guidelines" established by the Electronic Industries Federation of America, the European Information and Communication Technology Association, and the Japan Green Procurement Survey Standards Promotion Program on PCB board.