The clock is ticking
The deadline to remove lead and other hazardous substances from equipment is bearing down on the electronics industry amidst confusion about what needs to be done to show compliance to the European legislation
By James Carbone -- Purchasing, 6/16/2005 2:00:00 AM EDT
Time is running out for electronics companies to meet European Union's ban on the use of lead and five other hazardous substances in equipment sold in Europe. The Restriction on the Use of Hazardous Substances (RoHS) law requires that beginning in July 2006 electronics equipment sold in Europe, with some exceptions, must be free of lead, mercury, cadmium, chromium, polybrominated biphenyls, and polybrominated diphenyl ethers.
The ban is having a huge impact on the electronics industry and on purchasers at OEM and electronics manufacturing services (EMS) providers. Companies are substituting parts and changing manufacturing processes and buyers are monitoring which suppliers are making RoHS-compliant parts.
By some estimates, only about 25% of electronics suppliers are currently producing parts that are RoHS compliant. One reason many are not yet compliant is cost. Companies in the electronics supply chain will spend between $5-10 billion collectively to comply with the legislation, according to industry analysts.
Of the six banned substances, lead is the most widely used in the electronics industry. It is in solder to connect parts to boards and in the plating of parts. Companies are spending millions of dollars in finding lead-free alternatives and manufacturing processes to handle the lead-free parts.
The good news for buyers is that most major semiconductor suppliers have converted at least some parts to lead-free or are in the process of doing so and have settled on lead-free alternatives.
For instance, with reflow solder, many suppliers plan to use silver-tin copper rather than tin lead, although there are a host of other alternatives including tin bismuth, indium silver and tin zinc among others.
In semiconductors, lead has been used in a compound for lead frames, package leads and printed-circuitboard tabs. Some chip companies like Samsung will use a lead-free compound of tin bismuth and silver. Texas Instruments is using nickel-palladium gold finish in its leadframes for logic parts. With connectors, many manufacturers are using tin-over-nickel plating rather than lead-based plating.
While there is a cost to change to lead-free materials, suppliers say they are incurring even more cost because they need to run separate production lines for lead-free and leaded components.
"We can't just shove lead-free parts down customers' throats," says Joe Lampasona, quality director for a STMicroelectronics fab in Carrollton, Texas. "We have to keep two lines running for some period of time as we transition," he says. "If we build x amount of lead-free parts, someone will still want leaded parts. If we build leaded, they will want lead-free. It's a serious investment we have to make."
So confusing
Besides the cost of transitioning to lead-free and of running two lines, there are myriad issues surrounding RoHS compliance, not the least of which is proving compliance. With only about a year before the ban takes place, there is widespread confusion in the electronics supply chain about what electronics companies need to do to show RoHS compliance. There have been no set rules about documentation and compliance issued by the EU although some rules should be forthcoming soon. "We are all diligently awaiting those rules," says attorney Holly Evans, president of Strategic Counsel, a firm that advises companies on environmental regulations. "There is frustration in the industry because the rules have not been decided and the deadlines are looming."
She says electronics companies are trying to put compliance programs in place, but "they are operating in a vacuum. Without more information from the EU and member states it is a guessing game."
Evans says the European Commission has formed the Technical Adaptation Committee (TAC) which is comprised of representatives from member states. TAC is supposed to establish a process for ensuring that RoHS provisions are met. She says options being discussed by TAC include supply chain declaration and market surveillance/ testing.
While TAC has not made any decisions yet about compliance and enforcement, Evans says RoHS compliance will be a self-declaration system. "Companies will declare that they are in compliance. The question is how do you support that declaration?" says Evans.
Until the EU issues rules for compliance, Evans recommends buyers follow guidelines issued by the United Kingdom's Department of Technology and Industry.
The UK has proposed a due-diligence approach which may be used by other European countries. Rather than expecting manufacturers to prove that every part they buy is lead-free, EU member states will likely want manufacturers to establish documented and auditable systems to prevent noncompliant products from entering the EU.
Such systems could include forming a corporate-wide compliance team, developing a corporate RoHS statement and developing a RoHS compliance roadmap.
Buyers at companies also need to look closely at the parts they purchase from suppliers to determine where RoHS substances may exist within the company's equipment. Lead in solder and surface finishes are obvious, but hazardous substances can also be in cables, plastics and housings.
Purchasers should also establish a supply chain material declaration process, says Evans. RoHS requires manufacturers to know what substances are prohibited in their products. Companies should establish a database for the information that they will receive from their suppliers so they can use it to determine compliance, she says.
"The more you document, the more you show that your supplier assessment and analysis appear reasonable, the better you can argue that you have done all you could to ensure products are RoHS compliant," says Evans.
Evans adds that the UK guidelines provide monetary penalties for noncompliance, but until the EU issues rules concerning compliance and enforcement, it is unclear who will issue penalties. If the EU gets aggressive in enforcement it likely will go after large OEMs. "When push comes to shove, if EU does enforcement it will be against the big guys," says Evans.
While large OEMs will be subject to enforcement, OEMS aren't the only links in the supply chain affected by RoHS. The EMS industry is impacted as well. After all, EMS providers build most of the equipment for OEMs including the printed circuit boards which must have lead-free parts and solder.
Switch hitting
EMS providers are switching to RoHS-compliant parts and manufacturing processes, but like semiconductor companies, they also have to maintain leaded lines for customers, says Art Morgan, director of technical marketing for EMS provider Solectron in San Jose, Calif.
"We will have lead-free and leaded lines for the foreseeable future," says Morgan. "Our telecom and networking customers will be doing tin lead builds for a long time," he says. (Telecommunications and networking infrastructure equipment is exempt from RoHS.) But having two types of manufacturing lines is costly.
"With wave solder equipment you can buy conversion packages and they are not cheap. It is a huge investment," says Morgan. "You have to make the process fool-proof. You have to cordon off certain sections of the shop floor," he says.
Solectron has segregated lead-free lines from leaded lines and has trained it employees on lead-free parts and manufacturing processes and RoHS compliance. It has also segregated inventory at its plants.
"The days of mixing components down on the shop floor where you can have a common bin of components, are gone. We can't do that anymore," says Morgan. Manufacturing processes for leaded components are different than lead-free parts. Lead-free solder has a higher melting temperature than lead-based solder and leaded parts may not be able to withstand the higher soldering temperatures.
A big issue facing EMS providers in transitioning to lead-free processes is building equipment at the same quality and reliability levels as equipment that uses leaded parts and processes. Morgan says lead-free has its reliability issues, which is why there are exemptions to RoHS, such as telecommunications and networking equipment.
Growing whiskers
Such equipment is often in the field for years and lead-free parts are not as reliable in certain conditions over time. One problem that can result with lead-free parts is "tin whiskers," which are thin filaments that can grow on the surface of plating. The whisker can break off inside an assembly and cause the failure of a system.
The exact cause of whiskers is not known, however, whisker inhibitors and annealing are used to help reduce their growth. Sean Riley, regional market manager for connector manufacturer FCI, says most major connector manufacturers are using whisker inhibitors to solve the problem in new products particularly for fine-pitch connectors. "They are including trace chemicals in their tin plating to inhibit the growth of whiskers," he says.
FCI's lead-free plating of choice is pure tin over nickel. Riley says the selected plating has performed well under severe test conditions applied during its qualification program regardless of the pitch of the product.
Mike O'Connell, director of product marketing for connector maker Molex, also reports success with its tin-over-nickel plating. Very fine-pitch product down to 0.5-mm pitch is still under review, but the company is confident nickel plating will eliminate whiskering in its lead-free products. "No one has been able to duplicate tin whiskering if they use a true nickel barrier underneath the tin plating," says O'Connell.
Another issue is so-called "popcorning" which can occur during soldering. Tin-lead solder's melting point is 183°C while lead-free tin silver copper's melting point is 217°C. Component packages are made of compounds that have moisture in them. During soldering the compounds heat up and the moisture turns to gas and tries to expand through the compound of the package and can cause a break in the packaging. Baking and sealing of the part needs to be done to prevent this.
The challenge for EMS providers is to develop manufacturing processes and tests to ensure that reliability of systems is not compromised by lead-free.
While RoHS is a major issue for the EMS industry it may be equally challenging for smaller suppliers in the electronics industry who lack the resources of larger electronics companies. A case-in-point is Whitney Blake, a manufacturer of wire and cable assemblies and flexible power cords. Whitney Blake had used cadmium in many of its cords which are used with radios and military and medical equipment. Cadmium provides durability and long-term flexibility of cords.
"We can't just change materials," says Paul Carter, president of Whitney Blake. "We have certain requirements for products in the marketplace. They have to perform to a certain level. There are temperature requirements with the cords. And some require a quarter million flexes without failure," he says. To meet requirements, Whitney Blake had to do extensive research and testing on alternative materials and developed a proprietary alternative.
Number, please
Another RoHS issue is part numbers. Many buyers and EMS providers want suppliers to issue new part numbers for RoHS-compliant parts. Without new part numbers there is a fear RoHS-compliant parts will get mixed up with leaded parts in inventories.
Some suppliers are issuing new numbers, but others are saying by a certain date their parts will be RoHS compliant. Other suppliers say they label a box or bag of parts as being lead-free.
"Putting a tag on a bag or putting in a date code doe s not work well with our IT systems when you are doing materials planning," says Morgan. "It is important for them to change their part numbers."
It is unclear how many suppliers will issue new part numbers. A survey conducted by market researcher Technology Forecasters for electronics distributor Avnet last fall found 52% of suppliers will issue new part numbers. Arrow Electronics expects about 72% of semiconductor suppliers and 49% of passive and electromechanical suppliers to issue new part numbers for RoHS compliant parts. Some suppliers had planned to keep the old part numbers, but heard the outcry for new numbers from distributors and buyers and decided to issue new ones.
Leonie Tipton, vice president of global supply chain programs for Arrow, says some suppliers think new part numbers may create more confusion. "One reason suppliers are reluctant to change part numbers is they feel it is the right thing for customers," says Tipton. "They don't want to disturb the bill of materials selection and make more work for customers."
The good news is large suppliers like Intel and Texas Instruments will change part numbers. However, smaller suppliers and suppliers of low-tech items like screws and mechanical parts likely won't issue new numbers.
Keeping track of new part numbers and which parts have transitioned to lead-free is proving to be a daunting task for electronics distributors. If a manufacturer does not change part numbers, many distributors will issue their own new part numbers to make sure lead-free parts don't get mixed up with leaded parts. Distributors are also segregating inventory of lead-free and leaded parts.
Distributors say they are acting as a clearinghouse for information about lead-free parts. Many buyers are turning to distributors to keep track of which parts from which suppliers are compliant. "There is a great hunger for information," says Tipton. "The role of distributors is to help customers understand the impact of the legislation on them and to provide the data and tools available to manage the issue," she says.
Evans, the environmental consultant, says while there is much hand wringing in the supply chain over RoHS compliance, she doesn't expect any major problems as the clock ticks down on the RoHS deadline.
She says if there is a case of noncompliance, it will be due to "something that slips through the cracks." She says the electronics industry has been taking such aggressive steps to be RoHS compliant.
"You put good programs in place, you use a materials declaration guide to help track materials, you test where there appears so be a risk and you continue to improve your system," says Evans. "That's all you can do."
Replacements for tin lead (SnPb)
| Chemical name | Description | Soldering temperature (Celsius) |
| Source: PCNAlert |
||
| InSn | Indium tin | 118 |
| SnBi | Tin bismuth | 138 |
| InAg | Indium silver | 143 |
| SnZn | Tin zinc | 199 |
| SnAgCuSb | Tin silver copper antimony | 217 |
| AuSn | Gold tin | 281 |
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