RoHS: An update on this important Green Initiative

In 2003, legislation was introduced in the EU to promote the collection, treatment, recycling, and recovery of waste from electrical and electronic equipment. This legislation is known as the ‘Waste Electrical and Electronic Equipment (WEEE) Act’ and is formally dictated by directive 2002/96/EC of the European Parliament.

A complimentary directive, the Restriction of Hazardous Substances (RoHS), was also introduced in 2003 given by 2002/95/EC of the European Parliament. Beginning July 1, 2006, RoHS legislation restricted the amounts of Lead (Pb), Cadmium (Cd), Mercury (Hg), Hexavalent Chromium (Cr6+), Polybrominated Diphenylethers (PBDEs), and Polybrominated Biphenyls (PBBs) in electronic and electrical equipment.

These chemicals are known to present a risk to human health and the environment. Each European Union member state will adopt its own enforcement and implementation policies using the directive as a guide.

Manufacturers outside the European Union may wonder what RoHS has to do with them; after all, it's a European directive. The reality is that RoHS principles are global. The directive indicates that anything covered by RoHS entering the European Union must be compliant, whether they include cables made in China, parts molded in the USA, or PCBs made in Japan.

If a product is eventually destined for the EU, it is impacted by RoHS. In addition, the EU is not the only global entity taking steps to reduce the toxins in electronic devices. California's Electronics Waste Recycling act of 2003, for example, echoes the RoHS directive and has been implemented since January 1, 2007. Japan, China, and Korea are also expected to follow with laws of their own:

Japan : A ministerial ordinance Japanese industrial standard for Marking of Specific Chemical Substances (J-MOSS), effective from July 1, 2006, directs that some electronic products exceeding a specified amount of the nominated toxic substances must carry a warning label.

South Korea: South Korea promulgated the Act for Resource Recycling of Electrical and Electronic Equipment and Vehicles on April 2, 2007.

China: Final Measures for the Administration of the Control and Electronic Information Products (often referred to as China RoHS) has the stated intent to establish similar restrictions, but in fact takes a very different approach. Unlike EU RoHS, China RoHS does not give exemption to any type of product. Either the product is China RoHS compliant or is not a China RoHS Compliant.

Getting down to RoHS specifics
RoHS is often referred to as the lead-free directive, but it restricts the use of the following six substances:

1. Lead (Pb)
2. Mercury (Hg)
3. Cadmium (Cd)
4. Hexavalent chromium (Cr6+)
5. Polybrominated biphenyls (PBB)
6. Polybrominated diphenyl ether (PBDE)
(PBB and PBDE are flame retardants used in several plastics.)

The maximum permitted concentrations are 0.1% or 1000 ppm (except for cadmium, which is limited to 0.01% or 100 ppm) by weight of homogeneous materials. This means that the limits do not apply to the weight of the finished product, or even to a component, but to any single substance that could (theoretically) be separated mechanically—for example, the sheath on a cable or the tinning on a component lead.

In an effort to close RoHS loopholes, in May 2006 the European Commission was asked to review two then excluded product categories (monitoring and control equipment, and medical devices) for future inclusion in the list of products that must fall into RoHS compliance.

The directive applies to equipment as defined by a section of the WEEE directive. The following numeric categories apply:

1. Large household appliances.
2. Small household appliances.
3. IT & Telecommunications equipment (although infrastructure equipment is exempt in some countries)
4. Consumer equipment.
5. Lighting equipment—including light bulbs.
6. Electronic and electrical tools.
7. Toys, leisure, and sports equipment.
8. Medical devices (currently exempt)
9. Monitoring and control instruments (currently exempt)
10. Automatic dispensers.
11. Semiconductor devices

It does not apply to fixed industrial plant and tools. Compliance is the responsibility of the company that puts the product on the market, as defined in the directive; components and sub-assemblies are not responsible for product compliance. Of course, given the fact that the regulation is applied at the homogeneous material level, data on substance concentrations needs to be transferred through the supply chain to the final producer.

RoHS Exemptions
Exemptions to RoHS are granted to narrowly-defined applications for which the elimination of prohibited substances is technically or scientifically impracticable or when the only available substitution produces more negative than positive benefits to the environment, health, or consumer safety.

Exemptions are temporary in nature and subject to review at least every four years, until such time as a reliable and safe substitution is available. For this reason, many exemptions carry an expiration date.

On September 24, 2010, the European Commission adopted a substantially revised list of RoHS exemptions and replaced the entire Annex for clarity. Currently there are 39 exemptions in RoHS directive.

Hazardous and High-Tech trash problem
RoHS and other efforts to reduce hazardous materials in electronics are motivated in part to address the global issue of consumer electronics waste. As newer technology arrives at an ever increasing rate, consumers are discarding their obsolete products sooner than ever. This waste ends up in landfills and in countries like China to be “recycled.

In addition to the high-tech trash problem, RoHS acknowledges the long-term effects of low-level chemical exposure on populations. New testing is capable of detecting much smaller concentrations of environmental toxicants. Researchers are associating these exposures with neurological, developmental, and reproductive changes.

RoHS is in contrast to historical and contemporary law that seeks to address only acute toxicology that is direct exposure to large amounts of toxic substances causing severe injury or death.

Life-Cycle Impact Assessment
1. Lead-free solder. Study results are providing the industry with an objective analysis of the life-cycle environmental impacts of lead-free solders, allowing for practical consideration of environmental concerns along with the traditionally evaluated parameters of cost and performance. This assessment is also allowing manufacturers to redirect efforts toward products and processes that reduce solders' environmental footprint, including energy consumption, release of toxic chemicals, and potential risks to human health and the environment.

2. BFR-free plastics . The ban on concentrations of brominated flame retardants (BFR) above 0.1% in plastics has had an impact on plastics recycling. As more and more products include recycled plastics, it has become critical to know the BFR concentration in these plastics, either by tracing the origins of the recycled plastics to establish the BFR concentrations, or by measuring the BFR concentrations from samples. Plastics with high BFR concentrations are costly to handle or to discard, whereas plastics with levels below 0.1% have value as recyclable materials.

Benefits of RoHS compliance
RoHS helps reduce injury to people and damage to the environment in third-world countries where much of today's “high-tech trash” ends up. The use of lead-free solders and components has provided immediate health benefits to electronics industry workers in prototype and manufacturing operations. Contact with solder paste no longer represents the same health-hazard it did before.

Reliability concerns unfounded. Contrary to the predictions of widespread component failure and reduced reliability, today, millions of compliant products are in use worldwide. Most of today's consumer electronics are now RoHS compliant. Examples include Apple's iPod portable music players as well as Dell and HP home computers and servers

Flow properties and assembly. One of the major differences between lead-containing and lead-free solder pastes is the “flow” of the solder in its liquid state. Lead-containing solder has a lowe surface tension and tends to move slightly to attach itself to exposed metal surfaces that touch any part of the liquid solder. Lead-free solder, conversely, tends to stay in place where it is in its liquid state and attaches itself to exposed metal surfaces only where the liquid solder touches it.

 Lack of “flow”. While typically seen as a disadvantage because it can lead to lower quality electrical contact, this can be used to place components in tighter proximity than they could be placed when using lead-containing solders.

Criticism from Industry
The long-term reliability of some of the proposed lead-free solders is still being debated. Reliability is too broad a subject to detail here, but numerous technical papers and articles have addressed the topic over the past few years. Whether “tin whiskers” or “tin pest” are real problems or only theoretical ones, such as lead landfill leaching, remains to be seen.

Unfortunately, none of the lead solder substitutes has a reliability data base approaching the 2,000-year history of tin-lead solder.While lead-free reliability is merely questionable, lead-free solder overall costs will unquestionably be higher than for tin-lead solder. Hundreds of millions of dollars have already been spent in the conversion process, including training, process development, qualification testing, and new equipment.

On-going operating costs for more expensive and scarcer materials, higher use of thermal energy, and longer and less forgiving (lower yield) production processes over time will add billions of dollars to electronics equipment costs, dwarfing the conversion outlays. Higher costs and lower profits ultimately get passed along to customers as price increases.

Misapplied Resources: The invisible and non-recoverable cost of lead-free solder is what economists call an “opportunity cost.” The opportunity cost of lead-free solder is the hundreds of thousands of hours of skilled technical labor consumed in the lead-free preparation and conversion. The advances in electronics, manufacturing, new product development, and enhanced capabilities that these trained technical personnel might have achieved on other programs have instead been forfeited for a delusion.

Labeling for RoHS
RoHS does not require any specific product labeling. However, many manufacturers have adopted their own compliance marks to reduce confusion. Visual indicators in use today include explicit “RoHS compliant” labels, green leaves, check marks, and “PB-Free” .

RoHS Testing
Manufacturers of electrical and electronic equipment should check and monitor that no new products will exceed the maximum concentration limit of restricted substances such as Hexavalent Cr, Hg, Pb, Cd and Polybrominated Diphenylethers and Biphenyl ethers (PBDE and PBE) on their production processes.

XRF Screening (Preliminary Method). .Reliable, accurate, and fast screening for RoHS-restricted elements in all different kinds of materials is a daunting task. In practice, X-ray Fluorescence (XRF) analysis has proven to be an ideal analytical tool for fulfilling the main requirements of the industry. Minimal sample preparation and the direct measurement of solid samples distinguish XRF from any other elemental analysis technique.

With the shortest time-to-result and highest cost effectiveness, XRF screening (Figure 1 below ) provides indications as to whether and where hazardous substances may exist in a product according to RoHS. It is especially suited, for instance, to acquiring a quick overview on end-products.


Clickon image to enlarge.

Figure 1. X-ray fluorescence analysis provides indications of existence of whether and where hazardous substances may exist in a product .

Wet Chemical Analysis (Verification Method). RoHS testing is carried out using an initial screening test by XRF. Then, if high levels of restricted substances are found, further testing may be carried out using wet chemical analysis (Figure 2 below ) to produce more conclusive results with a high degree of accuracy.


Clickon image to enlarge.

Figure 2: RoHS Testing Flow Chart

RoHS Part Identification
Companies can differentiate RoHS compliant products from non-compliant products via distinct marketing part numbers. RoHS compliant products are identified with a letter added into the original part numbering system, which can be easily identified through a datasheet or part numbering detail sheet. For example, Cypress Semiconductor adds a suffix letter “X” in its marketing part numbers.

RoHS Marketing Part = CY7C199C-15VXC
Non RoHS Marketing Part = CY7C199C-15VC

Conclusion
The EU RoHS Directive is a great achievement for the world as a whole. As more and more countries adopt these standards, tomorrow's landfills will be less contaminated and its industrial workers healthier. RoHS has paved the way as a global standard for phasing out several hazardous chemicals in the electronics supply chain.

Many companies have moved beyond RoHS, and there are numerous products on the market today that do not contain halogenated organic substances. Technical performances and fire safety standards can now be met with readily available alternative materials and components.

Companies doing business with European Union Member States will be required to comply with laws regarding the reduction of hazardous substances and the proper disposal of electronics waste. Late adopters of RoHS technology will risk inventory obsolescence, may experience their products being rejected at borders, and will be at high risk for loss of market share.

Abhishek Gupta is a business analyst for Cypress Semiconductor. He has a B.E. in Electronics & Communications from Maharishi Dayanand University, Haryana, India. He has worked with Agilent Technologies as a Logistics Coordinator (RoHS Specialist) and can be reached at agni@cypress.com.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.