RoHS stands for Restriction of Hazardous Substances and is an important regulatory standard that impacts the electronics industry. RoHS compliance dictates restrictions on certain hazardous substances in electronic products and components. For printed circuit board (PCB) manufacturers, understanding and implementing RoHS compliance is crucial.
This guide will provide a comprehensive overview of RoHS, including:
- RoHS directive history and timeline
- Substances restricted under RoHS
- RoHS scope and exemptions
- Requirements for PCB manufacturing
- How to demonstrate RoHS compliance
- RoHS certification standards
- Cost impact of RoHS compliance
- Future outlook for RoHS
Overview and History of RoHS
RoHS stands for “Restriction of Hazardous Substances” and originated as a European Union directive known as “Directive 2002/95/EC” adopted in February 2003. The original RoHS directive focused on restricting certain hazardous substances in electrical and electronic equipment (EEE).
The motivation was to address health and environmental concerns around substances like lead, mercury, cadmium and other heavy metals found in electronics. RoHS regulations mandated stricter limits on these substances with a combined threshold percentage limit of 0.1% by weight per homogeneous material in applicable EEE.
The current version of the RoHS Directive is referred to as “RoHS 2” or “RoHS Recast.” It was published as Directive 2011/65/EU which updated and recast the original legislation. RoHS 2 expanded the scope of products covered while keeping the restricted substances largely the same.
Some key dates in the history of RoHS adoption include:
- February 2003 – Original RoHS Directive 2002/95/EC enters into force
- July 2006 – RoHS 1 takes effect and EEE in EU market must comply
- January 2009 – Commission exempts medical devices until 2014
- January 2011 – Commission exempts monitoring equipment until 2014
- July 2011 – RoHS 2 Directive 2011/65/EU is published
- January 2012 – RoHS 2 enters into force
- January 2013 – RoHS 2 compliance required
RoHS has gone through gradual expansion of its scope over the years since its inception while maintaining focused restrictions on some key hazardous substances.
Restricted Substances Under RoHS
The RoHS directives impose restrictions on the following main substances:
- Lead (Pb)
- Mercury (Hg)
- Cadmium (Cd)
- Hexavalent chromium (Cr6+)
- Polybrominated biphenyls (PBB)
- Polybrominated diphenyl ether (PBDE)
The maximum threshold level permissible for these restricted substances by weight in homogeneous materials is 0.1% (1000 ppm).
Additionally, RoHS 2 added four phthalates to the list of restricted substances:
- Bis(2-ethylhexyl) phthalate (DEHP)
- Butyl benzyl phthalate (BBP)
- Dibutyl phthalate (DBP)
- Diisobutyl phthalate (DIBP)
These hazardous substances were included in electronics primarily due to their properties in applications like lead solder, mercury switches, cadmium plating, and flame retardant plastics. However, the potential risks posed led to regulations limiting their use. Eliminating these from the supply chain required a major shift in materials and processes for the electronics industry.
RoHS Scope and Exemptions
RoHS 2 expanded the scope of applicable product categories versus RoHS 1. The legislation covers electronic equipment and devices that:
- Rely on electric/electromagnetic fields for functioning
- Generate, transmit, or measure such fields
- Use voltage not exceeding 1,000 volts AC and 1,500 volts DC
Within scope categories under RoHS 2 include:
- Large and small household appliances
- IT equipment like computers and servers
- Consumer electronics
- Lighting equipment including lamps and luminaires
- Monitoring instruments and control gear
- Automatic dispensers
- Power tools
- Toys and sports gear with electronic components
- Medical devices (from 2014)
Out of scope categories include military equipment, aerospace equipment, certain large-scale industrial tools, implantable medical devices, photovoltaic panels and some others.
Within the product categories covered under RoHS 2, the legislation allows for certain applications and materials to be exempt from the substance restrictions based on technical feasibility or reliability. Some current exemptions include lead in high melting temperature solders, lead in glass or ceramics, lead in server or storage system batteries, among others.
RoHS Requirements for PCB Manufacturing
Printed circuit board manufacturing and assembly is squarely within the scope of RoHS 2, since PCBs are core components of nearly all electronic equipment. This has major implications for PCB material sourcing, fabrication, assembly, and testing processes in order to comply. Here are key requirements for PCB manufacturing under RoHS:
Substrate and Laminate Materials
- Base substrate materials like FR-4 must not contain brominated flame retardants like PBB or PBDE exceeding the 0.1% threshold
- Prepreg bonding films also cannot contain these hazardous brominated compounds
- Ceramic or composite substrates need to avoid restricted phthalates
- Lead-free solder alloys like tin-silver-copper must be used instead of tin-lead solder
- Solder flux also should not contain prohibited substances
- Surface finishes need to eliminate hexavalent chromium and cadmium plating
- Alternatives like immersion tin, immersion silver, OSP or ENIG should be used
- Parts need RoHS compliant termination finishes and lead-free soldering
- Must avoid lead, cadmium and other restricted substances
Marking and Documentation
- RoHS labels, markings should be present both on bare boards as well as assembled PCBs
- Certificate of Conformity and test documentation required
Adhering to these guidelines ensures PCB manufacturing avoids any use of restricted hazardous substances per RoHS 2 standards.
Demonstrating RoHS Compliance
Since RoHS regulations pertain to end products sold in the EU market, PCB manufacturers must be able to demonstrate RoHS compliance through documentation and traceability. Key ways to show compliance include:
- Suppliers of substances, materials like laminates must provide material declaration forms listing any restricted substances and their concentrations.
Certificates of Conformity
- Certificate to declare RoHS compliance for the specific product being placed on EU market.
- Independent lab testing reports to validate concentrations of restricted substances in materials or components are below permissible levels. This can involve analytical testing like GC/MS.
- RoHS compliant labels, markings on PCBs and consumer end products. For example “RoHS” or “Lead-Free.”
Chain of Custody
- Documentation tracking materials through the entire supply chain to prove compliance at every step.
Maintaining this documentation provides evidence of RoHS conformance during any audits or regulatory inquiries.
RoHS Certification Standards
To ease the burden of compliance demonstration, industry standards have been developed that allow manufacturers to certify their products or materials are RoHS compliant once criteria are met. Two common standards include IPC and UL certification programs.
IPC-1752 Class D Materials Certification
- Standard published by IPC to certify materials as RoHS compliant with extensive testing requirements and stringent control levels.
- Allows materials suppliers to produce independent certification.
- Class 1-3 also exist for parts and components, PCBs, and electronics assemblies.
UL 1007 Standard
- Published by Underwriters Laboratories (UL) as a standard for RoHS materials verification
- Covers restricted materials testing methodology and acceptable concentration levels
- UL issues certificates for complying materials as recognized proof of RoHS conformance.
By having materials or boards be certified through these standards, manufacturers have recognized means to demonstrate RoHS compliance to customers and regulatory authorities.
Cost Impact of RoHS Compliance
Transitioning to RoHS compliant materials, components and processes did involve some cost increases for electronics manufacturers:
- Reformulation of laminates, prepregs, coatings to replace brominated FR additives
- New plating processes like immersion silver instead of hexavalent chromium
- More expensive solders like SAC alloys instead of tin-lead
- Component costs increased from lead-free terminations, marking, compliance testing
- New process controls around material handling, storage and traceability
- Increased documentation, certification, and record-keeping overhead
However, over time these costs diminished as compliant materials and processes matured and economies of scale optimized RoHS implementation. Substitutes like halogen-free FR materials eventually reached cost parity with older materials. Solder costs also declined.
For PCB manufacturers, careful supplier management and process controls enabled cost-effective RoHS compliance. The regulation is now well-integrated into electronics manufacturing.
Future Outlook for RoHS
As awareness around sustainability grows, expectations are for the scope and stringency of RoHS regulations to expand further:
- EU has stated intention to periodically review and add restricted substances to RoHS as needed.
- Exemptions may also be phased out over time if technically feasible substitutes emerge. This pushes industry to develop innovative solutions.
- More product categories and electronics could come under RoHS legislation as scope gaps get addressed.
- Tighter control limits on maximum permissible concentrations are also possible.
- Expect alignment and convergence between different global environmental regulations.
For PCB companies, retaining organizational agility and supply chain flexibility will be key to adapt to future RoHS changes. Staying abreast of emerging substitutes and sustainable materials will also allow companies to turn compliance into competitive advantage.
RoHS stands as one of the most influential environmental regulations shaping the electronics industry over the past two decades. Its restrictions on hazardous substances fundamentally changed materials, components and processes for PCB manufacturing.
While adapting to RoHS compliance did entail costs and process changes, manufacturers have largely integrated its ethos into operations. With proper material evaluation, process controls, certification and documentation, PCB assemblers can readily demonstrate RoHS conformance.
As the scope expands and companies focus more on sustainability, RoHS principles will continue guiding the industry’s responsible use of materials for benefit of human health and the environment.
Frequently Asked Questions
Here are some common questions around RoHS compliance for PCB manufacturing:
Q: Does RoHS apply to PCB manufacturers outside the EU?
RoHS applies to any PCBs that will end up in products sold or imported into the EU market, irrespective of where they are manufactured. So PCB assemblers globally must comply if boards will reach EU countries.
Q: How are RoHS regulations enforced for non-compliant products?
Within the EU, enforcement is handled at the national member state level through market surveillance. Customs agents or regulators can do sample procurement and testing to check for compliance, issuing penalties for violations. They can also force recall and disposal of non-compliant products.
Q: Can any deviations be allowed from the maximum substance concentration limits under RoHS?
In general, RoHS takes a strict interpretation of the 0.1% threshold substance limit in materials. However, the IPC-1752 standard does permit maximum levels of up to 0.2% for cadmium and mercury to account for measurement uncertainties and trace contaminants. Still, the main limit remains 0.1%.
Q: Does RoHS restrict only substances intentionally added or even trace contaminants?
RoHS covers both intentionally added restricted substances as well as contaminants arising from production of the material that may exceed permissible thresholds. Manufacturers are responsible for limiting both.
Q: Can normal FR-4 laminates still be used in RoHS compliant PCBs?
Yes, as long as the FR-4 laminate meets RoHS requirements. Usually this means replacing the brominated compounds previously used for flame retardancy with polymeric or reactive phosphorous-based FR additives that are RoHS compliant. RoHS-compatible FR-4 laminates are widely available.
Q: Does RoHS compliance also require lead-free component soldering?
Yes, for an assembled PCB to be fully RoHS compliant it requires lead-free soldering. So components must have lead-free terminations and lead-free solder alloy like SAC305 must be used to solder components to the board. Lead-free solder process controls are part of overall RoHS conformance.
What is RoHS and Why is Important
In 2003, the European Union (EU) created a legislation to restrict the use of hazardous substances in Electronics and Electrical industry for the sake of environmental and people safety and health issues. This legislation itself is known as RoHS (Restriction of Hazardous Substance)
We know that electronics and electrical industries have soared too much. People are buying electronics at unimaginable pace, from smart phones, to IoT products, computers, laptops, house hold equipment, auto industry, Wire, cables, connectors, components are widely available in the market from lowest grade quality to highest grade quality.
The low quality component and devices are cheap and high quality is expensive. So people tend to buy cheaper electronics to fit in their budget constraints. However they do not realize the dangers associated with cheap quality electronics, components and devices. Low quality products means products using Non-RoHS electronic components/materials in them.
ROHS Products are Expensive..!
The one biggest problem of RoHS is nothing more than “Expensive Products”. Why would a company choose components/materials for manufacturing their product that are expensive (RoHS compliant)..?
These expensive components or materials used to manufacture product will surely increase the price of end product thus reducing the profit margin of the company. This is the reason why many EE companies opt for Non-RoHS components.
This is the same case with individuals whose TV set if have some problem, that individual will use lead solder (that is cheap) for de-solder or repair purpose because lead free solder is little bit expensive so as to save money but in return inhaling solder fumes which is deadly for lungs.
So the question is “Should we use materials (as an EE company and individual working as hobbyist or repairman) that comply with RoHS standards while realizing that the end product or cost of service will increase thus possibly declining profit and reducing market. The answer as per the EU standards (CE Mark) is YES..!
This is because RoHS standards were designed not considering the financials or monetary implications of any individual or a company but to ensure welfare of people in terms of health and cleaner environment
Dangers Associated with Non-RoHS Materials:
As mentioned that RoHS legislation standards are important because to make sure that environmental pollution is reduced and people health care issues are resolved. Imagine a company that has a PCB assembly and PCB manufacturing facility where materials that are Non-RoHS compliant are used. Now you can imagine that people who are engaged in daily routine work on a conveyer belt handling those materials will suffer from different diseases of skin and lungs cancer, mesothelioma and asbestosis.
Those labor which are packaging these Non-RoHS PCB materials and products will also suffer because they handle materials with their bare hands. Thus everyone involved in handling these stuff manufacturing labor, packager, supplier, distributor will not be affected immediately or shortly but will be affected in longer run surely.
The dangers associated with Non-RoHS products/materials is not just limited to manufacturing and handling but during and after use, they are discarded and become part of Landfills. Because of longer life cycle of these Non-RoHS materials they do not decay soon, but take very long time to degrade/decay. Thus when thrown away in landfills (holes in the ground), their traces are mixed in underground water resources hence polluting environment, plants and fishes.
Why was ROHS introduced..?
Keeping in view above hazards, RoHS directives 2011/65/EU known as RoHS-2 was introduced in 2011 and directives 2015/863 known as RoHS-3 was introduced in 2015.
RoHS-2 directives 2011/65/EU introduced the restriction on the use of Bis (2-ethylhexyl) phthalate (DEHP) and Di-isobutyl phthalate (DIBP). The ROH-2 was specific for medical instruments for monitor and control and other EE equipment not covered. ROHS-2 also included the CE (Compliance Europe) Marking standard.
RoHS-3 added 4 new materials in the list of six Non-RoHS restricted materials under directive 2015/863. These are Bis (2-ethylhexyl) phthalate (DEHP), Butyl benzyl phthalate (BBP), Di-butyl phthalate (DBP) and Di-isobutyl phthalate (DIBP)
The End of Life Vehicle (ELV) is another directive of EU about the scrap cars and waste materials regarding wires, cables and electrical accessories. The ELV directive restricts the use of banned materials in the list given below in automobile industry.
WEEE stands for Waste Electronic and Electrical Equipment. The Collection, treatment and recycling of waste electronics is the mandate of WEEE directive. It urges the electronic and electrical product manufacturers to comply with this standard otherwise legal action will be taken against those who do not comply in terms of thousands of dollar fine.
On the other side, awareness of WEEE and RoHS needs to be spread. The EE product designers and manufacturers need to make products such that they facilitates extraction of useful components and materials like silver, gold, platinum, copper, aluminum, during recycling process.
RoHS Restricted Materials:
The RoHS standards have defined the admissible (minimum) amount of restricted materials that can be used in a product. This amount is measured in Parts per Million (ppm). So 1 ppm means out of every 1 million parts of RoHS compliant material, only 1 part of RoHS non compliant material is allowed.
The list of total 10 restricted materials along with their ppm (RoHS non compliant) is given below
- Cadmium (Cd): < 100 ppm
- Lead (Pb): < 1000 ppm
- Mercury (Hg): < 1000 ppm
- Hexavalent Chromium: (Cr VI) < 1000 ppm
- Polybrominated Biphenyls (PBB): < 1000 ppm
- Polybrominated Diphenyl Ethers (PBDE): < 1000 ppm
- Bis(2-Ethylhexyl) phthalate (DEHP): < 1000 ppm
- Benzyl butyl phthalate (BBP): < 1000 ppm
- Dibutyl phthalate (DBP): < 1000 ppm
- Diisobutyl phthalate (DIBP): < 1000 ppm
RoHS in Europe:
If you are still using one of the RoHS non complaint substances listed above and you are anywhere outside Europe then it is fine, but if you are in Europe then you may have to face consequences in terms of heavy penalty or even imprisonment. Any EE product that is sold in Europe it MUST be RoHS complaint and CE certified.