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 國內家電廠商﹐請注意了 - ZT |
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白丁
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加入时间: 2004/02/22
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作者：白丁 在 海归商务 发贴, 来自【海归网】 http://www.haiguinet.com
Get the lead out!
European legislation banning lead in electronics equipment won't affect just Europe. The ban will mean suppliers will produce lead-free parts globally.
By Jim Carbone
October 23, 2003
Design for environment is a term that electronics buyers will be hearing more in the next three years because of European legislation that will ban the sale of electronics products that contain lead.
Earlier this year, the European Union passed the Restriction of the Use of Hazardous Substances (ROHS) law that will ban the use of lead in equipment such as computers, cell phones and consumer electronics equipment sold in Europe. The ban goes into effect in July of 2006 although there are a number of exemptions such as lead in cathode ray tube (CRT) displays.
Besides lead, the ban also covers mercury and cadmium and several other substances. However, electronics production will be affected by the lead ban because lead is a staple in component packages and in solder. ROHS means semiconductor and other component manufacturers will have to use lead-free materials for packages and solder.
While the law seemingly only affects Europe, it will in fact result in most parts being manufactured lead-free worldwide. It doesn't make sense for electronics manufacturers to make lead-free components and materials for Europe and lead components for the rest of the world.
"It is a global industry. How are you going to sort out lead-free and tin-lead product?" asks Jasbir Bath, process engineer for electronics contract manufacturer Solectron. "Europe is a big market," he says. "An exporter into Europe and other areas has to cover all the markets so it will be difficult for him to build the same product lead-free and with lead for different areas of the world. European legislation is almost like a global movement to move to lead free," says Bath.
Besides component manufacturers, the transition to lead-free will also impact OEMS and their electronics manufacturing services (EMS) providers. While many component manufacturers see the ROHS as a hassle, some OEMS are taking the high road and plan to introduce lead-free equipment before the 2006 deadline for marketing purposes. That means they'll need lead-free parts from suppliers and lead-free assembly processes from their EMS partners who build their printed circuit boards.
The responsibility to make sure parts being used in equipment are lead-free will fall on the shoulders of purchasers especially at the EMS provider. "The sourcing of the components will definitely change," says Sean McDermott, regional supplier, quality engineer specialist at Celestica in Toronto. "There will have to be more engineering input, more working with suppliers and customers to make sure that the component being sourced is the right one for the product," he says.
Thilo Sack, advisory engineer, corporate technology at Celestica, says all the upfront work is necessary. "In this new environment you almost have to treat every component as a custom part initially," he says. "You can't just take the parts for granted. In the past, you would never think twice about ordering a capacitor or resistor because those are Chicklet parts. Now you almost have to treat every part initially like a custom part and make sure that every thing is spec'd out the way it is supposed to be."
The reason for the extra care is a part can have a lead-free finish, but may not be compatible with a lead-free soldering process. "There is confusion," says McDermott. "We are telling everyone at Celestica when you hear 'lead-free' from a supplier to determine what that actually means. A lot of things that are advertised today as lead-free might be the outer coating lead has been removed. However, there are a number of things that have to be changed like properties of the parts which allow them to be rated at higher temperatures," he says.
With lead-free, a different solder material has to be used rather than tin lead. The industry seems to have settled on a tin silver copper solder as the alternative. The new solder material requires a temperature of 217°C for it to get to the a liquid state for soldering. Tin lead's melting temperature is 183°C.
No popcorn wanted
Lead-free parts need to be qualified to the higher soldering temperatures, which require different load compounds in the packages. "Molded compounds gather moisture when you heat them up rapidly," says Ron Gedney, staff consultant for the National Electronics Manufacturing Initiative (NEMI). NEMI is a consortium of electronics companies that has conducted studies on lead-free materials.
"The moisture expands when you get above 100°C and it becomes a gas and tries to expand through the molding compound," he says. "It can't get out so it tends to break or pop the molding compound like a popcorn effect. The industry has set up a number of procedures for baking out and sealing the component," he says.
Many buyers are concerned that the transition to lead-free will mean higher prices for parts. Some suppliers such as Texas Instruments and STMicroelectronics say they don't expect to increase prices because of the transition to lead-free although their costs are higher. Other suppliers are non-committal.
McDermott says he is expecting higher prices for lead-free parts at least initially. "It will depend on the part. For simpler parts like resistors and capacitors increases will be fairly modest. More customized parts will probably have greater percentage impact."
However, Gedney of NEMI expects most suppliers will absorb the actual cost. Many of the materials in lead-free components and solder are more expensive than lead. For instance a lead-free solder costs about 2.5 times more than lead-based solder. However, the amount of materials used in solder and in the component plating is so small that the overall impact on the price of the component isn't high, according to Gedney.
How's supply?
Besides price, buyers whose companies plan to switch to lead-free components and processes before the 2006 deadline may have to be concerned about supply of lead-free parts. Many suppliers are just beginning to transition parts over to lead-free.
Some buyers are surveying their suppliers about their lead-free plans. Case-in-point: EMS provider Solectron. "We have initiated supplier surveys to determine who has qualified their parts to the new higher temperature ratings with lead-free terminations and are ready to supply us parts," says Kim Hyland, director of process integration at Solectron. "We will set up a database that will serve as a log of which suppliers have met the current industry standards. We will have an extensive database of parts that are lead-free ready as our OEM customers start to migrate over to lead-free equipment," he says. That database will also include new part numbers for lead-free products.
"Actually one of the major debates today is part numbering," says Hyland. "The folks who are going into production (mainly Japanese companies) have not requested new part numbers of our suppliers. Whereas in Europe and the Americas our customers want new part numbers for anything that is lead-free ready," he says.
"In general we do not plan to change part numbers," says Michael Hundt, director of packaging development for semiconductor manufacturer STMicroelectronics. However, if a customer requests a change for a lead part that transitions to lead-free, STMicroelectronics will change the number, according to Hundt.
However, there will be exceptions. "We'll have an existing part number with lead and change the number when we transition the part to lead-free but that will be on a specific customer request basis," he says.
He adds on the parts themselves STMicroelectronics will put a letter "e" on the part to show it is lead-free. "Every box, tube or tape and reel package will have a clear statement on it that it is lead free. On top of that we will give customers a 90-day notice with the process change notice that will tell them after this date code the product will be lead free," he says.
What a hassle
Suppliers expect meeting the 2006 deadline for lead-free parts won't be a problem although it will mean more work. "Lead-free is a major point of turbulence in our industry because it is largely a hassle," says Hundt. "It is a tremendous burden on production control, sales and marketing people more so then the technical people."
Hundt says STMicroelectornics will use nickel palladium in most of its parts rather than lead. In some cases it will use pure tin plating.
Most of our discrete devices and commodity products already converted. "Every factory that we have— seven major plants— are ready to go. All are running at least samples for early customers," he says.
He says STMicroelectronics is in a "phase-in" period for lead-free parts. "It will drag out for next year. Not all customers are ready for lead-free, not all customers want it and not all customers require it," says Hundt. He says cell phone manufacturers and handheld equipment manufacturers are driving the early transition to lead-free.
Many suppliers are seeing growing demand for lead-free products from Japanese consumer electronics manufacturers. While Japan doesn't have any law banning lead, in 1998 it passed legislation concerning recycling pf appliances including televisions, refrigerators, washing machines and air conditioners.
It didn't ban the use of lead but it increased the cost of recycling for manufacturers if their products contained lead. "It implied that OEMs should move away from lead and Japanese manufacturers have been doing that since 1999," says Hyland.
Bragging rights
Doug Romm, senior packaging engineer for Texas Instruments, says TI is seeing growing demand for lead-free parts from Japanese manufacturers. "We have a number of major customers who said they see lead-free as a competitive opportunity," he says. "Major players in Japan are saying 'I can market my products as lead free and that is enough of a reason for me to force my suppliers to give me lead-free now." We have major customers in Japan with consumer products and we are supplying lead-free to them. They are bringing out products in 2003 and late 2004," says Romm. "The market is driving lead-free in Japan, not legislation."
He expects OEM customers in Europe to start moving to lead-free parts late this year and in 2004. "They don't want to be doing this the last minute," says Romm.
The move to lead-free components won't be a problem for Texas Instruments, according to Romm. Reason: TI converted to lead-free materials for some logic parts in the late 1980s. "At that time we were looking for a solution primarily for fine pitch components and we developed a nickel-palladium finish which happened to be lead-free," says Romm. With a nickel palladium finish rather than a lead finish, TI removed a post-mode plating process from its assembly operation.
"That cut our handling of components such as solder plating and dipping of components. Those steps can result in potential quality issues," says Romm. "We eliminated all the chemicals associated with plating when we went to the pre-plated finish. We were ahead of the curve in having our components converted to lead-free finish in the 1980s," he says.
To date TI has 50 billion parts in the field that use that lead-free finish," according to Romm. Around 2000, TI converted from nickel-palladium to nickel-palladium-gold, a slight variation. "It is more preferred by our customer base as far as wetting performance," says Romm. He adds that besides lead frame packages, TI has qualified its surface mount Microstar ball grid array (BGA) and Microstar junior packages for lead-free.
"They have lead-free ball options. We are working to qualify other array packages and expect to have those qualifications by early 2004," says Romm. He says all TI 's logic parts will meet the ROHS requirements by the end of the year and all other TI parts will meet the legislation in early 2004.
Growing whiskers
While TI is using nickel-palladium-gold as its lead substitute in plating, other manufacturers plan to use pure tin or tin alloys such as tin-copper, tin-silver or tin-bismuth. However, pure tin has many of the same characteristics as lead.
The electrolytes used for pure tin plating are similar to the ones used for tin-lead plating and the same equipment can be used. In addition, the melting point of pure tin and tin lead is similar and the speed of wetting and solderability are about the same.
Pure tin is also compatible with tin-lead solders as well as new lead-free solders. The problem is tin finishes have a propensity under certain conditions to grow filaments or whiskers on the surface of the plating. While the exact cause of whiskers is not known, it is believed it occurs due to stress resulting from copper-tin intermetallic compound formation, according to researchers at the Shipley Co., which supplies electronic materials for semiconductor fabrication. To mitigate or lessen the compound formation, a nickel undercoat, post plating annealing or thicket coatings can be used.
Whiskering is a problem because if they grow on the surface of the lead frame they can break off. "They can grow long enough on fine pitch leads," says Romm. "They can fall off inside an assembly and cause shorting of the system in an electronic system."
However, tin whiskers are not a long-term issue, according to Hundt of STMicroelectronics. He says STMicroelectronics, Infineon and Philips have conducted a joint study of whiskers and have developed a way to prevent them using annealing and an increase in plating thickness.
"In a nutshell, the technical recipe is to maintain a minimum thickness of 7 microns in the plating and after plating you anneal (heat) it for an for an hour at 125°C and you don't get tin whiskers."
Gedney of NEMI says while there are migrating procedures such as the one STMicroelectronics is doing to minimize whiskers. However, no one is sure why whiskers form. Until that is determined, it will be hard to come up with away to prevent them.
Is it worth it?
Trying to develop a process to prevent tin whiskers, developing lead-free solders and lead-free alloys for plating are examples of how ROHS is impacting suppliers. Some analysts and suppliers question whether it is worth it from an environmental perspective.
"Electronics uses 1% of the world's lead," says Hundt of STMicroelectornics. "The bulk of lead is used in wheel weights and batteries."
"They have granted the automotive industry an exemption where a car can contain 60 grams of lead in the electronics. There is no pressure on the automotive world," says Hundt.
There are other exemptions. A lot of telecommunications equipment is exempt as are high-end servers and CRTs which have about two pounds of lead in them. Electronics that go into factories are also exempt.
"By and large we don't care about exemptions because we are going to convert to lead free,' says Hundt. STMicroelectronics expects to have total conversion by the end of next year. "However, any customers who want lead-free parts now just have to ask," he says.
While suppliers are transitioning to lead-free parts, it is unclear how stringently ROHS will be enforced. The law calls for stiff fines for violators and the legislation is aimed at OEMs.
"In Europe there is a trend toward producer responsibility," says Paul Semenza, an iSuppli analyst. "You build it, your name is on it, you are responsible for it throughout its life cycle. There are certain ways you can dispose of the toxic parts of them. It's going to be the OEM who has that responsibility. That's why OEM customers are pushing on the component manufacturers for lead-free parts."
McDermott of Celestica says it will be a challenge for suppliers to meet the lead-free requirements, but it will also be an opportunity for them. "If they can come out with products that meet the lead-free requirement there is an opportunity to be sourced into more products,' he says.
How substitutes compare with lead
Lead substitute Use Advantage/disadvantage
Tin-silver copper Solder Higher reliability, higher melting point, costs 2.5 times more than lead
Tin-copper Solder Higher melting point, doesn't wet well, similar reliability, higher cost.
Pure tin Plating Whisker problems, similar cost, similar reliability
Tin-Bismuth Plating May lessen whisker problem, similar reliability, higher cost.
Source: National Electronics Manufacturing Initiative, industry sources
Lead-free at a glance
The Restriction on the Use of Certain Hazardous Substances directive by the European Union will have far reaching implications for the global electronics supply chain because suppliers will likely not build both lead-free products for Europe and lead parts for the rest of the world.
Here are details of the initiative and what it covers.
Effective date: July 30, 2006
The goal: To prevent hazardous materials from being used in electronics equipment that may end up polluting the environment after they are disposed.
Substances banned: Lead, cadmium, mercury, hexavalent chromium, polybrominated bi-phenyls, and polychlorinated diphenyl ethers.
Materials affected: Plating on electronic components and solder.
Equipment affected: All equipment dependent on electrical currents or electromagnetic fields. Includes computers and telecommunications equipment, consumer electronics equipment, electrical and electronic tools, toys, monitoring equipment and automatic dispensers.
Industries and products exempted. The auto industry, lead in cathode ray tubes, high-end servers, storage and array systems, networking infrastructure equipment, mercury in fluorescent lights.
Souece: Purchasing
作者：白丁 在 海归商务 发贴, 来自【海归网】 http://www.haiguinet.com
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 國內家電廠商﹐請注意了 - ZT -- 白丁 - (35898 Byte) 2003-11-19 周三, 18:36 (1552 reads)
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