.
- Lists of components and materials it contains.
- Locations of dangerous substances.
- For repair.
- For possible upgrading.
- For reuse.
- For disassembly.
- For recycling.
- To integrate recycled material into new equipment.
If the ban on lead in electronics is such a grand idea, I wonder just how many of the people who lobbied for the RoHS Directive and SB20/SB50, or the politicians who voted for these laws, would be willing to ride first-class for free on a trans-Atlantic or trans-Pacific airline flight-- if they were told that:
I am a cheapskate, and I'm proud of it! Whether I design, build, or buy something, I intend it to have a long, useful life. The upcoming conversion to digital TV in the US doesn't worry me, because giving up my average of 1 hour per year of TV watching will give me more reading time! When I want to watch a videotape, my 1981 Curtis Mathis TV set and my 1986 Magnavox VCR will continue to work just fine. My 1986 Realistic stereo continues to play my LP records, after I replaced a defective capacitor some years ago. Early this year I had to replace the power supply and hard disk in my desktop computer, which I bought in 2001, so it should be good for another couple of years. I *have* retired my 1984 Toyota pickup truck, after putting just over 304,800 miles on it. The muffler broke off, destroying the catalytic converter in the process. It would cost me at least twice as much as the truck is worth just to replace those two items. And it was approaching time to replace the tires and alternator too. So goodbye "Truckie". I'm now driving the diesel Rabbit that I bought from my girlfriend in 2001, after she bought a new car. It now has 104,000 miles on it, and should be good for another 40,000 miles or so.
Whereas my girlfriend bought a new brand-name computer and monitor in December 2003, whose warranties ran out in December 2004. In January 2005 the power supply in her computer blew up with a loud bang! I fixed her computer, after doing about an hour of "metal mangling" to install a replacement generic power supply in place of the original custom power supply (which is almost impossible to obtain, and very expensive). Her monitor acted up about three weeks later, making a loud buzzing noise, and overloading her uninterruptable power supply (UPS). So I gave her one of my old monitors, which I had stashed away in case of computer trouble, which she has been using with no further problems. I've tested her monitor, by itself and connected on her old computer, without being able to duplicate the problem yet... My father was a TV repairman in the 1950's and 1960's, and intermittent problems were always the toughest ones for him to solve. And legislators wonder why "people hang onto old, obsolete electronic equipment"?
In the over 4,700 books and other documents that I have now collected on lead-free and RoHS-compliant electronics, there are numerous reports of major materials- and process- compatibility problems. Many of these are quality problems, and thus can be found by thorough testing during manufacturing. But there remain many latent reliability problems that may take months or years to show up-- at which time our expensive electronic doodad can suddenly turn into an unrepairable piece of junk. And we still don't have ways to find some of these problems by stress testing or accelerated- life testing.... I suspect that, for a while, we will be darned lucky if a piece of "RoHS- compliant" electronics gear lasts six months longer than its warranty. Personally, I don't plan to buy any new electronic products or equipment between January 2006 and July 2007. After a RoHS- compliant unit has been in production for at least a year-- with a good field history-- I might consider buying one if I'm truly desperate. But for the next few years, the warranties on new electronics will be more important to me than their features or their prices.
Nevertheless, most electronics manufacturers will have no choice-- if they want to stay in business-- except to comply with these misbegotten laws as best they can. Some of the proposed national and state laws have quite Draconian penalties for non-compliance-- no matter how minor. For example, in 2001/2002 Sony spent an estimated $86 million to replace peripheral cables in 1.3 million PlayStations, because they contained more cadmium than permitted under a Dutch law akin to the RoHS Directive. As I see the situation, the only people who are guaranteed to benefit from the RoHS Directive will be hordes of petty bureaucrats, hired to enforce the Directive, and people/companies providing RoHS-testing services, to give manufacturers some level of protection from those bureaucrats. Equipment manufacturers may benefit for a while, because it looks like most electronics manufacturers will have to set up new production lines, with all new equipment, to prevent "contaminating" RoHS-compliant products by equipment and tools that have been previously used with tin-lead solder.
Please note that I am currently working on my first lead- free, RoHS- compliant, and WEEE- compliant product. So the vast majority of the information in this web page is based on the engineering and scientific literature, and not on my personal experience. All of the laws that I discuss on this web page-- that affect how we design and manufacture electronic equipment and products-- were enacted after I became an EMC Engineer for dBi Corporation in early 2002. The majority of my work is electromagnetic compatibility (EMC), electromagnetic immunity (EMI), and electrostatic discharge (ESD) testing for our clients. And to date I have been 100% successful at getting our clients' products/equipment to comply with the applicable domestic and international EMC/EMI/ESD standards and laws. But I take professional pride in helping ensure that any project that I work on will be a success. Therefore, given the chance, I try to consult with clients and prospective clients long before they reach the prototyping and testing phases, to point out the best ways I know to meet:
We must consider many new materials- and process- compatibility issues when trying to develop lead- free, RoHS- compliant, and WEEE- compliant electronics. So far no one has been able to come up with a blanket recommendation to "do A, B, and C, and all your problems will be solved". I can't even give you specific recommendations, without fairly- intimate knowledge of your company's products, and some familiarity with your design and manufacturing processes. So just as I have done in my books, I intend this web page to:
Many governments, organizations, and some companies are worried about how to safely dispose of all of this electronic waste, or "e-Waste". The EPA estimates that 1-4% of municipal solid waste consists of discarded electrical and electronic equipment. A major concern is the presence of toxic metals and chemicals, which can leach into the groundwater from landfills, or pollute the air if the electronic waste is incinerated:
The European Union published the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment Directive ( RoHS Directive, 2002/95/EC) in volume 46 issue L37 pages 19-23 of the OJ on February 13, 2003. This Directive takes effect on July 1, 2006, and with some exceptions (Annex) totally bans the use of (Article 4.1):
Article 2.3 explicitly states that spare parts for the repair of electrical and electronic equipment put on the market before July 1, 2006 do not fall under the RoHS Directive. Nor does the reuse of electrical and electronic equipment put on the market before July 1, 2006. I.e., the electrical equipment is already in the European Union, and out of the manufacturer's control as of July 1, 2006. Owners of equipment acquired before this date may repair or upgrade their equipment, to extend its lifetime, instead of being forced to discard it.
Council Decision COM(2004) 606, adopted Sept. 23, 2004), amends the Annex of the RoHS Directive to permit-- in any application that was not already exempted--a homogenous material to contain a maximum of:
The second amendment to the RoHS Directive was published in volume 48 issue L280 pages 18-19 of the OJ on October 25, 2005, adding some additional exemptions to the Annex.
The DTI has published a draft of the United Kingdom's version of the RoHS Directive as "Part IV - The RoHS Directive - draft implementing Regulations."
The DTI has also published draft Guidance Notes for the RoHS Directive, dated July 2004. A revised draft RoHS REGULATIONS Government Guidance Notes just came out in August 2005.
The European Union published the Waste Electrical and Electronic Equipment Directive (WEEE Directive, 2002/96/EC) in volume 46 issue L37 pages 24-38 of the OJ on February 13, 2003. Directive 2003/108/EC, published in volume 46 issue L345 pages 106-107 of the OJ on December 31, 2003, amends Article 9 of the WEEE Directive with regard to the financing of WEEE for businesses. The WEEE Directive:
.
The DTI has also published draft Guidance Notes for the WEEE Directive, dated July 2004. According to these Guidance Notes, producers must register with the (UK) National Clearing House by August 13, 2005 (pages 4, 20-21).
The European Union also bans many flame retardants that might be used in printed circuit boards (PCB's) under the Restrictions on the Marketing and Use of Certain Dangerous Substances and Preparations Directive (Directive 76/769/EEC) which has been amended 39 times since it was published in the OJ in September 27, 1976.
The European Union published the Batteries and Accumulators Containing Certain Dangerous Substances Directive (Battery Directive, 91/157/EEC) in volume xx issue L78 pages 38-41 of the OJ on March 26, 1991. Directive 98/101/EC, published in volume 42 issue L1 pages 1-2 of the OJ on January 5, 1999, clarifies the limitations on mercury in batteries. The Battery Directive permits lead-acid and nickel-cadmium batteries to be used in electrical and electronic equipment as long as they contain less than 0.0005% by weight of mercury. Button cells and batteries made from button cells are permitted to contain up to 2% mrecury by weight (Article 3.1).
The European Union published the Energy-using Products (EuP) Directive (EuP Directive, 2005/32/EC) in Volume 48 issue L191 pages 29-58 of the OJ on July 22, 2005. This Directive took effect on August 11, 2005. It sets up a framework for regulating products that:
China's Ministry of Information Industry has drafted a Management Methods for the Prevention and Control of Pollutants from Electronic Information Products law, often referred to as "China RoHS". This law has not been adopted yet. But if adapted, after July 1, 2006 it would ban:
California passed Proposition 65, the Safe Drinking Water and Toxic Enforcement Act of 1986 in 1986. This act affects companies who:
California adopted Senate Bill No. 50 (SB50) on September 29, 2003, amending SB20 in a number of areas, but the combination is usually still referred to as "SB20". SB20 and SB50 create a number of bureaucratic hurdles and snares for anyone who sells-- or wants to sell-- video display devices with screens larger than 4 inches diagonal (with some exceptions, SB50, pages 9, 11; SB20, page 9) to consumers in California:
California Legal Council's digest of SB50, on page 2, (3) says "The act requires each manufacturer of an electronic device who sells a covered electronic device in this state to submit an annual report to the board on the number of electronic devices sold by the manufacturer". On page 6, 25214.10.1 specifies the information that a manufacturer must suppy to retailers and the State Board of Equalization. On page 9, 42463(f) defines the "covered electronic devices". On page 10, 42463(n) defines "manufacturer". On page 11, 42463(t) defines "video display device". On pages 11 and 12, 42464.6(a) gives the Department of Toxic Substances Control the authority to determine what is, or is not, a "covered electronic device". On pages 13 and 14, 42465.2 specifies the information that the manufacturer must supply to the California Integrated Waste Management Board, consumers, and the Department of Toxic Substances Control.
For the actual implementation of SB20 and SB50, California's Health and Safety Code Section 25214.9-25214.10.2, under 25214.10(a) effectively bans lead, cadmium, mercury, and hexavalent chromium in "covered electronic devices" to the limits permitted by the RoHS Directive by January 1, 2007, or the effective date of the RoHS Directive, whichever comes later.
Furthermore, California's Public Resources Code Section 42463, 42463(f) defines "covered electronic device", 42463(n) defines "manufacturer", and 42463(t) defines "video display device".
California's actual regulations implementing SB20 and SB50 are in Emergency Regulations. 18660.5(23) has this snare for manufacturers-- "These catagories include, but are not limited to, (my italics) ...". 18660.41 specifies information that manufacturers must report to the California Integrated Waste Management Board, while 18660.42 specifies information that manufacturers must provide to consumers.
Maine adopted LD 743 (amended by HP 549) on May 14, 2003. This law bans disposal of CRT's in landfills after January 1, 2006.
Massachusetts, under 310 CMR 19 paragraph 19.017(3)(c), has not permitted cathode ray tubes (CRT's) to be deposited in landfills, or incinerated, since April 1, 2000.
Minnesota adopted H.F. No. 882 in 2003. This law bans disposal of CRT's in landfills after July 1, 2005.
Maryland adopted House Bill 575 on May 10, 2005. This law requires computer manufacturers that manufactured more than 1,000 computers per year, averaged over the last three years, to register with the (Maryland) Department of the Environment if they wish to sell new computers in the state after December 31, 2005. The initial registration fee is $5,000. The registration fee then drops to $500 per year if the manufacturer has implemented a "computer takeback program". Otherwise the registration fee continues at $5,000 per year. This law will expire December 31, 2010 unless it is renewed by the legislature.
References: [1], [2]. [3], [4], [5], [5a], [6], [7], [8], [9], [10], [10a] [11], [11a] [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [21a], [48 pages 4-11, 31, 424-425]
An important point to remember is that "lead-free" does not necessarily mean "RoHS-compliant", and "RoHS-compliant" does not necessarily mean "lead-free". If any homogeneous material-- anywhere in the electronic product-- contains too much lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB's), or polybrominated diphenyl ethers (PBDE's), then the entire unit is not "RoHS-compliant". This could be something as insignificant as one inspection stamp on one board of a multi-million dollar machine... Similarly, the glass of a large cathode-ray tube (CRT) could contain several pounds of lead. But since it falls under exemption 5 in the Annex of the RoHS Directive, it can be "RoHS-compliant" and not "lead-free".
As I see the situation, almost all of us electronic engineers are going to be heavily affected by the ban on lead in the RoHS Directive, "China RoHS", and SB20, regardless of whether we feel these laws are wise or incredibly asinine. Personally, from January 2006 to about July 2007 I doubt that I will buy any electronic product or equipment that touts it is "RoHS Compliant". I'm also stocking up on 60/40 and 63/37 rosin-core tin-lead solder for my home workshop, and already have about 70 pounds of it in various gauges... Which should be enough for all the home projects I'll want to build, electronic things I'll need to fix, and junk electronics I'll dismantle for useful parts before I die or get too blind to work on them.
Article 4.1 of the RoHS Directive says "Member States shall ensure that, from 1 July 2006, new electrical and electronic equipment put on the market does not contain lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB) or polybrominated diphenyl ethers (PBDE)." The Department of Trade and Industry (DTI) in the United Kingdom is pushing for the impurity limits to be ( Guidance Notes for the RoHS Directive, item 26):
There are a few lead-free solder alloys that have melting points close to that of eutectic tin-lead solder (63Sn37Pb, 183 degrees Celsius). But they either use fairly-rare elements like indium, or they have poor mechanical/chemical properties compared to tin-lead solder, or both.
Most of the lead-free solder alloys that are available in quantity, and aren't too-hideously expensive, have melting points at least 30 degrees Celsius higher than eutectic tin-lead solder. Some electronic components that we have been using for decades, such as aluminum electrolytic capacitors, can not survive these higher processing temperatures. With the longer dwell time at high temperature required by many of the lead-free solders, "popcorning" of plastic semiconductor packages is a major problem. The higher temperature and longer dwell time can also crack vias and plated-through holes in PCB's, causing intermittent opens when the PCB is stressed in use. (The resin exceeds its Glass Transition Temperature (Tg), greatly increasing the laminate's Thermal Coefficient of Expansion (TCE) versus that of the copper plating in the barrels.) Thus we may need much tighter process controls to prevent damage to components and PCB's during assembly and rework. Finding lead-free components that can survive these tougher processing conditions can be difficult. Many products will have to be completely requalified because of all the component and process changes. And due to lead-free component availability, we are likely to have a transition period during which we make products with a mixture of lead-containing and lead-free components, leading to reliability issues.
We can still use NiCad and lead-acid (gel cell) batteries in electronic and electrical devices, even though the RoHS Directive bans cadmium and lead, because they fall under the Battery Directive. The DTI's Guidance Notes for the RoHS Directive, item 14.v says that the RoHS Directive does not apply to batteries, because the WEEE Directive requires them to be removed from the equipment when it is collected as waste.
Mercury has been banned in many countries for a number of years, so the RoHS Directive's ban on it doesn't hurt us too much.
There are also many alternative flame retardants to the PBB's and PBDE's, so the RoHS Directive's bans on them aren't too painful either.
The WEEE Directive does not directly affect the cost of a product. But it requires the manufacturer or importer to include a (hidden) allowance in the selling price for collecting and disposing of the product when the user is finished with it. By designing a product to be easy to dismantle and recycle, we can reduce this allowance and thus the selling price -- making our product more attractive to prospective users.
patent situation
Making a solder joint involves five materials:
For molten solder to properly wet another metal (PCB holes/pads and component leads/balls) that metal also must be somewhat hotter than the solder's melting point. SnPb solders typically require about 20 to 50, typically 35°C superheat. A nitrogen atmosphere (nitrogen blanket) can reduce the superheat required by some lead-free solders, and thus the reflow/wave soldering temperature required.
A near-eutectic or near-peritectic solder composition, with a narrow pasty range, reduces the temperature range and thus the time span during which the solder joints are sensitive to movement during solidification, and thus the likelihood of "cold solder joints". A narrow pasty range also reduces the chances of "fillet lifting", where the solder shrinks severely as it cools and solidifies, breaking loose from the PCB pad. Eutectic compositions are also more fluid in the liquid state than non-eutectic composotions of the same metals. For solders with a wide pasty range, they may react with a significant fraction of the terminal alloy and board alloy before they are fully fluid. A wide pasty range does help when the solder must fill wide gaps.
In general, adding elements to a solder alloy greatly increases the chances for the composition to go awry during manufacturing, storage, and the soldering process. Thus we will usually prefer either a binary or a ternary solder alloy for their lot-to-lot consistency and their low sensitivity to variations in the platings or coatings on PCB's and component leads/balls. Solder paste has a very-high surface area, and thus is susceptible to oxidation. We must pay close attention to solder paste's shelf life and total "open time" if we want reliable solder joints. Solder alloys used for wave soldering are held at high temperature for long periods in direct contact with the solder pot, pump, nozzles, etc. Lead-free solders tend to be much more corrosive than SnPb solders, contaminating the solder and maybe damaging the equipment. Elements like zinc can oxidize and be carried out in the dross, also changing the solder composition. And the molten solder can dissolve copper and other elements from the components and PCB's being soldered, gradually contaminating the solder bath, and affecting the quality of solder joints.
Insensitive to Pb contamination. SnBiPb melts at 96°C.
Can be repaired and reworked.
Cost comparable to SnPb solder.
Mineral Commodity Summaries 2005
Doesn't require large quantities of rare elements. The electronics industry is currently using about 4,000 metric tons (1 metric ton = 10^3kg) of solder paste and 35,000 metric tons of solder bar per year. Thus, assuming that this averaged 60% tin and 40% lead, solder consumed about 24,000 tons per year of lead (Pb). Switching to a tin- silver (SnAg) or tin- silver- copper (SnAgCu) solder with about 3.5% of silver would consume about 2,100 tons of silver per year-- whereas her Table 8.11 shows that about 1,500 more tons of silver could be produced per year. Tin-bismuth (SnBi) solders require at least 40% bismuth, which would consume about 24,000 tons of bismuth per year. Whereas Table 8.11 shows that at most 4,000 more tons of bismuth could be produced each year. Tin-indium (SnIn) solders require at least 5% indium, which would consume about 3000 tons of indium per year. Whereas Table 8.11 shows that at most 100 more tons of indium could be produced per year. (Adjust these numbers for the density of the different solders.)
Adequate mechanical strength and ductility.
Reasonable Thermal Coefficient of Expansion (TCE).
Good fatigue resistance, creep resistance, and corrosion resistance. reliability drops as intermetallics get thicker. Voids are significantly more common in lead-free solder joints than in SnPb solder joints-- these are frequently the starting points for cracks and crack growth. voids due to gases that can't escape from molten solder. Many intermetallics are brittle. Their Temperature Coefficient of Expansion may differ from the bulk solder, causing cracking during thermal cycling. Intermetallics layers 1-5um thick are usually acceptable.
Low volume resistivity.
Compatible with fluxes during storage, preheating, and soldering.
The United States Occupational Safety & Health Administration (OSHA) ranks the toxicity of elements typically used in solders as Bi < Zn < In ?? < Sn < Cu < Sb < In ? < Ag < Pb. PEL = permissible exposure limit
Can be easily recycled.
Not restricted by patents. numerous patents on lead-free solders in different countries, many of these overlap because of tolerances on compositions. [48, pages 389-408] some patents cover not only the solder alloy, but also solder joints made with them. concern here is that in making a solder joint, get compositions that are a mixture of the solder and the plating or base metal of the component and the PCB, thus violating patent claims. licensing is one solution. trade barrier to selling product in country where a patent holds. SnAgCu may run into trouble with JP3027441 in Japan, JP09326554 in Japan, US6231691 in the US, and US5863493 in the US, and patent applications EP1213089, EP1196015, EP1180411 in Europe, US2002-0155024 in the US. SnCu may run into US6296722, JP10324482, JP10324483, and JP10069742.
solder paste stored at 35 to 45F; used in first-in first-out basis; let come to room temp 4 hours before opening; shelf life of SnAgCu 3-4 months versus 6 months for SnPb paste Sn3.5Ag wire good for hand rework; Sn3.9Ag0.6Cu paste good for rework; Sn0.7Cu or Sn3Ag0.5Cu in mini solder pot hold tip on joint longer than SnPb to ensure reflowing Solders are specified by the nominal percentage weight (1% = 0.01 of the total weight) of each element in the alloy. If the percentage of an element is not specified, it makes up the remainder of the alloy. Elements making up to 5% of the alloy typically have ±0.2% tolerance by weight. Elements making up over 5% of the alloy typically have ±0.5% tolerance by weight.
| Chemical Symbol |
Common Name |
Melting Point |
2004 Average Cost per kg | 2004 Worldwide Production, in 10^3kg | Volume Resistivity @20°C rhov(20), in Ohm-m |
Galvanic Potential in V |
Density, in 10^3kg/m^3 |
Thermal Conductivity, in W/m-°C |
OSHA PEL, in mg/m^3 |
Comments |
|---|---|---|---|---|---|---|---|---|---|---|
| Ag | Silver | 962°C | $210.00 | 19,500 | 1.63E-8 | 0.08 | 10.50E3 | 429 | 0.01 | byproduct of copper and lead mining |
| Al | Aluminum | 660°C | $1.80 | 28,900,000 | 2.73E-8 | 0.83 | 2.69E3 | 237 | 5 | |
| Au | Gold | 1064°C | $13,000.00 | 2,470 | 2.27E-8 | -0.11 | 19.3E3 | 317 | -- | byproduct of copper and lead mining |
| Bi | Bismuth | 271°C | $6.80 | 3,800 | 107E-8 | 0.18 | 9.75E3 | 8 | -- | tends to improve wetting of Sn, byproduct of copper and lead mining, limited availability |
| Cd (reference) | Cadmium | 321°C | $1.30 | 17,200 | 6.8E-8 | 0.67 | 8.65E3 | 97 | 0.005 | |
| Co | Cobalt | 1495°C | $54.00 | 46,900 | 6.34E-8 | 8.9E3 | 100 | 0.1 | ||
| Cr (reference) | Chromium | 1907°C | $5.40 | 17,000,000 | 12.7E-8 | 0.60 | 7.19E3 | 94 | 0.5 (+2, +3) 0.05 (+6); proposed 0.001 (+6) |
|
| Cu | Copper | 1085°C | $2.90 | 14,500,000 | 1.72E-8 | 0.22 | 8.96E3 | 401 | 1 | |
| Fe | Iron | 1538°C | $0.44 | 1,700,000,000 | 9.98E-8 | 0.68 to 0.78 | 7.87E3 | 82 | -- | |
| Ga | Gallium | 30°C | $550.00 | 69 | 13.6E-8 | 5.90E3 | 41 | -- | byproduct of aluminum, copper, and zinc mining | |
| Ge | Germanium | 938°C | $410.00 | 50 | 45E-8 to 0.50 | 5.32E3 | 60 | -- | byproduct of zinc mining | |
| Hg (reference) | Mercury | -39°C | $8.70 | 1,800 | 96.1E-8 | 13.55E3 | 8 | 0.1 | ||
| In | Indium | 157°C | $600.00 | 325 | 8.0E-8 | 7.31E3 | 82 | 0.1 | limited availability byproduct of lead and zinc mining |
|
| Mg | Magnesium | 650°C | $3.90 | 570,000 | 4.51E-8 | 1.73 | 1.74E3 | 156 | 5 | |
| Ni | Nickel | 1455°C | $14.00 | 1,400,000 | 7.20E-8 | 0.14 | 8.90E3 | 91 | 1 | |
| Pb (reference) |
Lead | 327°C | $1.20 | 3,200,000 | 21.3E-8 | 0.55 | 11.35E3 | 35 | 0.05 | |
| Pd | Palladium | 1555°C | $8,100.00 | 190 | 10.8E-8 | 0.08 | 12.02E3 | 72 | -- | |
| Pt | Platinum | 1768°C | $27,000.00 | 218 | 10.8E-8 | -0.20 | 21.45E3 | 72 | 1 | |
| Sb | Antimony | 631°C | $2.80 | 112,000 | 40.1E-8 | 6.69E3 | 24 | 0.5 | byproduct of copper and lead mining | |
| Si | Silicon | 1414°C | $1.80 | 4,700,000 | 60E-8 to 2300 | 2.33E3 | 148 | 5 | ||
| Sn | Tin | 232°C | $9.10 | 250,000 | 11.5E-8 | 0.52 | 7.31E3 (white) 5.75E3 (gray) |
67 | 2 | white beta-Sn stable at room temperature; gray alpha-Sn stable below 13°C and brittle |
| Zn | Zinc | 420°C | $1.20 | 9,100,000 | 6.06E-8 | 1.05 | 7.13E3 | 116 | -- | |
| Solder Alloy | Composition by Weight |
Melting Point |
Reflow Soldering |
Wave Soldering |
Metal Cost per kg | Comments |
|---|---|---|---|---|---|---|
| AuGe | 12% Ge remainder Au |
356°C | eutectic Au12Ge melts at 356°C | |||
| AuIn | 18% In remainder Au |
451 to 485°C | ||||
| AuSi | 3-3.6% Si remainder Au |
363-370°C | eutectic Au3Si melts at 363°C | |||
| AuSn | 20% Sn remainder Au |
280°C | eutectic Au20Sn melts at 280°C | |||
| BiIn | 33% In remainder In |
109°C | eutectic Bi33In melts at 109°C | |||
| GaInSn | 21.5% In 16% Sn remainder Ga |
10°C | eutectic Ga21.5In16Sn melts at 10°C | |||
| GeAl | 45% Al remainder Ge |
424°C | eutectic Ge45Al melts at 424°C | |||
| In | pure In | 157°C | ||||
| InAg | 3 to 10% Ag remainder In |
141 to 237°C | eutectic In3Ag melts at 143°C | |||
| Sn | pure Sn | 232°C | 170% | |||
| SnAg | 2 to 10% Ag remainder Sn |
221 to 295°C | 229 to 300% $13.73 [29] | eutectic Sn3.5Ag melts at 221°C Sn3.5Ag recommended by NEMI for wave soldering and hand soldering, high creep resistance long history of use resists fillet lifting if not contaminated with Pb, widely available |
||
| SnAgBi | 2 to 3.5% Ag 1 to 7.5% Bi remainder Sn |
205 to 220°C | 235°C | 217 to 310% | prone to fillet lifting | |
| SnAgBiCu | 1.3 to 3.5% Ag 0.8 to 46% Bi 0.5 to 4% Cu remainder Sn |
186 to 221°C | above 5% Bi can form SnBi melting at 138°C, or SnAgBi melting at
136.5°C, suffer from fillet lifting during wave soldering |
|||
| SnAgBiCuGe | 2% Ag 4% Bi 0.5% Cu 0.1% Ge remainder Sn |
216°C | ||||
| SnAgBiCuIn | 3% Ag 1% Bi 0.7%Cu 2.5% In remainder Sn |
204 to 215°C | ||||
| SnAgBiIn | 2.0 to 3.5% Ag 1.0 to 3.0% Bi 1.7 to 10.5% In remainder Sn |
179-213°C | ||||
| SnAgCu | 0.3 to 4.7% Ag 0.5 to 6% Cu remainder Sn |
216 to 380°C | 235 to 250°C | 200 to 330% | eutectice Sn3.8Ag0.7Cu melts at 217°C Sn3.8Ag0.7Cu recommended by IDEALS, Sn3.9Ag0.6Cu recommended by NEMI expensive silver is toxic |
|
| SnAgCuBi | see SnAgBiCu | |||||
| SnAgCuBiIn | 3% Ag 0.7% Cu 1% Bi 2.5% In remainder Sn |
204 to 215°C | ||||
| SnAgCuIn | 3 to 3.5% Ag 0.5 to 0.7% Cu 1 to 8% In remainder Sn |
214 to 217°C | ||||
| SnAgCuSb | 2 to 3.8% Ag 0.7 to 0.8% Cu 0.25 to 0.5% Sb remainder Sn |
213 to 222°C | 206 to 240% | eutectic Sn2.5Ag0.8Cu0.5Sb melts at 219°C compatible with SnPb |
||
| SnAgCuZn | 3.5% Ag 0.5% Cu 1% Zn |
227% | ||||
| SnAgIn | 3.5% Ag 1.5% In remainder Sn |
|||||
| SnAgInBi | 3.5% Ag 3-4% In 0.5-1% Bi remainder Sn |
202 to 214°C | ||||
| SnAgSb | 25% Ag 10% Sb remainder Sn |
233°C | ||||
| SnAgZn | ||||||
| SnBi | 40 to 58% Bi remainder Sn |
138 to 170°C | 190% $7.79 [29] | eutectic Sn58Bi melts at 138°C Bi has limited availability, mixing SnBi with SnPb can make an SnPbBi alloy that melts at 96°C if the Bi content exceeds 10.5% by weight recrystallization may cause expansion and brittleness tends to creep |
||
| SnBiAg | 7.5-57% Bi 0.1 to 2% Ag remainder Sn |
138 to 212°C | ||||
| SnBiIn | 20% Bi 10% In remainder Sn |
143 to 193°C | ||||
| SnCu | 0.7 to 3% Cu remainder Sn |
227 to 300°C | 242°C | 275°C | 150% $8.62 [29] | eutectic Sn0.7Cu melts at 227°C Sn0.7Cu recommended by NEMI for wave soldering, also used for flip-chip applications and as a component-lead finish, good wetting in an inert atmosphere (nitrogen blanket), tends to develop solder bridges and rough solder joints prone to growing tin whiskers, may transform to gray alpha-Sn |
| SnCuNi | ||||||
| SnCuSb | 0.7% Cu 0.3% Sb remainder Sn |
227 to 229°C | ||||
| SnIn | 8 to 52% In remainder Sn |
113 to 217°C | eutectic Sn52In melts at 118°C expensive, In has limited availability |
|||
| SnInAg | 20% In 2.8% Ag remainder Sn |
175 to 188°C | eutectic Sn20In2.8Ag melts at 188°C | |||
| SnInAgBi | 1-8% In 3-4.1% Ag 1-4% Bi remainder Sn |
|||||
| SnInAgBiCu | 8% In 4.1% Ag 2.2% Bi 0.5% Cu remainder Sn |
193 to 199°C | ||||
| SnInAgCu | 4-8% In 3-4.1% Ag 0.5% Cu remainder Sn |
|||||
| SnInCuGa | 5 to 6% In 0.5 to 0.7% Cu 0.4 to 0.6% Ga remainder Sn |
210 to 215°C | ||||
| SnInZn | 8.8% In 7.6% Zn remainder Sn |
181 to 187°C | ||||
| SnPb (reference) |
20 to 97% Pb remainder Sn |
183 to 315°C | 215°C | $5.87 [29] | eutectic Sn37Pb melts at 183°C soldering temperature must be about 35°C above melting point for reliable solder joints; Sn97Pb and Sn90Pb with melting points around 325°C are used for flip-chip connections |
|
| SnPbAg (reference) |
36% Pb 2% Ag remainder Sn |
179°C | eutectic Sn36Pb2Ag melts at 179°C high creep resistance good fatigue resistance prevents dissolving Ag terminations |
|||
| SnSb | 1 to 8.5% Sb remainder Sn |
232 to 245°C | 290°C | 290°C | $8.36 [29] | high creep resistance |
| SnZn | 9% Zn remainder Sn |
199°C | $7.99 [29] | eutectic Sn9Zn melts at 199°C poor wetting for reflow soldering poor compatibility with acid or alkaline fluxes corrodes easily |
||
| SnZnAl | 199°C | |||||
| SnZnBi | 5 to 8% Zn 3 to 10% Bi remainder Sn |
189 to 199°C | 140% | Sn8Zn3Bi solder paste has shelf life of only days or weeks | ||
| SnZnInBi | 5.5% Zn 4.5% In 3.5% Bi remainder Sn |
174 to 186°C | ||||
| ZnAl | 5% Al remainder Zn |
382°C | eutectic Zn5Al melts at 382°C | |||
The next three tables extend Tables C-1, C-2, and C-3 in Appendix C, Important Properties of Conductors and Ferrites, in my book Robust Electronic Design Reference Book, Volume 2.
| Conductor/ Ferrite |
Volume Resistivity @20°C rhov(20), in Ohm-m |
Temperature Coefficient of Resistance TCR(20), in 1/°C |
Relative Permeability, mur |
Saturation Magnetic Flux Density, in T |
Galvanic Potential in V |
|---|---|---|---|---|---|
| AuGe | |||||
| AuIn | |||||
| AuSi | |||||
| AuSn | |||||
| BiIn | |||||
| GaInSn | |||||
| GeAl | |||||
| In | |||||
| InAg | |||||
| Sn | 11.5E-8 | 0.0042 to 0.0047 | 1 | -- | 0.52 |
| SnAg | 11E-8 | 0.00041 | |||
| SnAgBi | |||||
| SnAgBiCu | |||||
| SnAgBiCuGe | |||||
| SnAgBiCuIn | |||||
| SnAgBiIn | |||||
| SnAgCu | |||||
| SnAgCuBi | see SnAgBiCu | ||||
| SnAgCuBiIn | |||||
| SnAgCuIn | |||||
| SnAgCuSb | |||||
| SnAgCuZn | |||||
| SnAgIn | |||||
| SnAgInBi | |||||
| SnAgSb | |||||
| SnAgZn | |||||
| SnBi | 38E-8 | ||||
| SnBiAg | |||||
| SnBiIn | |||||
| SnCu | |||||
| SnCuNi | |||||
| SnCuSb | |||||
| SnIn | 15E-8 | ||||
| SnInAg | |||||
| SnInAgBi | |||||
| SnInAgBiCu | |||||
| SnInAgCu | |||||
| SnInCuGa | |||||
| SnInZn | |||||
| SnPb (reference) |
14E-8 to 21E-8 | 1 | -- | 0.56 | |
| SnPbAg (reference) |
14.7E-8 | ||||
| SnSb | 14E-8 | ||||
| SnZn | 12E-8 | ||||
| SnZnAl | |||||
| SnZnBi | |||||
| SnZnInBi | |||||
| ZnAl | |||||
| Conductor/ Ferrite |
Density, in 10^3kg/m^3 |
Thermal Conductivity, in W/m-°C |
Emissivity Rating |
Melting Point, Tm in °C |
|---|---|---|---|---|
| AuGe | 356 | |||
| AuIn | 451 to 485 | |||
| AuSi | 285 | 363-370 | ||
| AuSn | 251 | 280 | ||
| BiIn; | 109 | |||
| GaInSn | 10 | |||
| GeAl | 424 | |||
| In | 157 | |||
| InAg | 141 to 237 | |||
| Sn | 7.00E3 to 7.35E3 | 62 to 74 | 0.04 to 0.15 | 232 |
| SnAg | 7.36E3 to 7.5E3 | 221 to 295 | ||
| SnAgBi | 205 to 220 | |||
| SnAgBiCu | 186 to 221 | |||
| SnAgBiCuGe | 216 | |||
| SnAgBiCuIn | 204 to 215 | |||
| SnAgBiIn | 179 to 213 | |||
| SnAgCu | 7.4E3 | 216 to 380 | ||
| SnAgCuBi | see SnAgBiCu | |||
| SnAgCuBiIn | 204 to 215 | |||
| SnAgCuIn | 214 to 217 | |||
| SnAgCuSb | 213 to 222 | |||
| SnAgCuZn | ||||
| SnAgIn | ||||
| SnAgInBi | 202 to 214 | |||
| SnAgSb | 233 | |||
| SnAgZn | ||||
| SnBi | 8.7E3 | 138 to 170 | ||
| SnBiAg | 138 to 212 | |||
| SnBiIn | 143 to 193 | |||
| SnCu | 7.3E3 | 227 to 300 | ||
| SnCuNi | ||||
| SnCuSb | 227 to 229 | |||
| SnIn | 7.3E3 | 113 to 217 | ||
| SnInAg | 175 to 188 | |||
| SnInAgBi | ||||
| SnInAgBiCu | 193 to 199 | |||
| SnInAgCu | 195 to 201 | |||
| SnInCuGa | 210 to 215 | |||
| SnInZn | 181 to 187 | |||
| SnPb (reference) |
8.2E3 to 11E3 | 35 to 51 | 183 to 315 | |
| SnPbAg (reference) |
49 | |||
| SnSb | 7.25E3 | 232 to 245 | ||
| SnZn | 59 | 199 | ||
| SnZnAl | 199 | |||
| SnZnBi | 189 to 199 | |||
| SnZnInBi | 174 to 186 | |||
| ZnAl | 382 | |||
| Conductor/ Ferrite |
Thermal Coefficient of Expansion, in m/m°C |
Surface Roughness, in m |
Thermoelectric Voltage, in V/°C |
|---|---|---|---|
| AuGe | |||
| AuIn | |||
| AuSi | 10E-6 to 12.9E-6 | ||
| AuSn | 16E-6 | ||
| BiIn | |||
| GaInSn | |||
| GeAl | |||
| In | |||
| InAg | |||
| Sn | 2.1E-6 to 33E-6 | SnAg | 22E-6 |
| SnAgBi | |||
| SnAgBiCu | |||
| SnAgBiCuGe | |||
| SnAgBiCuIn | |||
| SnAgBiIn | |||
| SnAgCu | |||
| SnAgCuBi | see SnAgBiCu | ||
| SnAgCuBiIn | |||
| SnAgCuIn | |||
| SnAgCuSb | |||
| SnAgCuZn | |||
| SnAgIn | |||
| SnAgInBi | |||
| SnAgSb | |||
| SnAgZn | |||
| SnBi | 15E-6 to 19E-6 | ||
| SnBiAg | |||
| SnBiIn | |||
| SnCu | |||
| SnCuNi | |||
| SnCuSb | |||
| SnIn | 20E-6 | ||
| SnInAg | |||
| SnInAgBi | |||
| SnInAgBiCu | |||
| SnInAgCu | |||
| SnInCuGa | |||
| SnInZn | |||
| SnPb (reference) |
21E-6 to 30E-6 | 5E-6 | |
| SnPbAg (reference) |
|||
| SnSb | 27E-6 | ||
| SnZn | |||
| SnZnAl | |||
| SnZnBi | |||
| SnZnInBi | |||
| ZnAl | |||
References:
[22, pages 396, 398, 401],
[23, pages 6-7, 10-11, 20-21, 24-27, 30, 32, 46-47, 53],
[24, pages 78-81, 1205-1209, 1328-1330, 1699-1701, 1703-1704, 1714-1720],
[25, pages 505-506, 614, 617-621, 623-624, 714-831],
[28, pages 37-42, 50-51, 53-61, 93],
[29, pages 6-10],
[33, pages 28-30, 74-75],
[34, pages C-3 to C-12],
[48, pages 27-29, 45-231, 263-264, 270-274, 277, 389-408, 415, 429-431, 444],
[49, pages 3.20-3.21, 11.14, 13.1-14.59, 15.3-15.13],
[50, pages 12, 49-136],
[51, pages 161-170, 305-310],
[68, pages 19-55, 81-91, 96-100, 103-129, 145-195, 218-221],
[86, pages 4-1 to 4-36, 12-45 to 12-47, 12-219 to 12-222],
[99, pages 1069-1101]
Sn2.9Ag0.6Cu or Sn3.5Ag balls Sn, Sn-Pd-Ag on lead frames Sn chip terminations Pb-bearing finishes with Pb-free alloys can cause fillet lifting datasheets show termination material, maximum temperature rating, recommended and maximum reflow temperatures, moisture sensitivity rating tested for solderability, temperature & humidity aging, moisture sensitivity level, thermal cycling relibility, mechanical shock, vibration, high temperature storage, pull strength, shear on Sn, SnCu, SnAg, NiPd, NiPdAu plating or terminations, tin whiskers, SnPb and SnAgCu reflow soldering, SnPb and Sn0.7Cu wave soldering SnBi plating unacceptable with SnPb solder paste--cracking no In or Bi with BGA's 0.15" (3.81mm) between BGA or CSP and leaded components to prevent secondary reflow during rework electroplate with Pd, SnCu, SnBi electrode dipping in SnAgBiCu moisture sensitivity levels drop http://www.leadfreesoldering.com/ lead-containing components usually spec'd for 4 seconds at 260 oC, lead-free reflow takes about 30 seconds at 260 oC
| Company | Lead Plating |
BGA Balls |
Tin-Whisker Prevention |
Compatible Solders |
Reflow Soldering |
Wave Soldering |
|---|---|---|---|---|---|---|
| 3M | ||||||
| Actel | Sn | SnAgCu | 245-250°C | |||
| Adam Tech | Sn | 260°C | ||||
| Advanced Interconnections | Au over Ni matte Sn over Ni |
SnAgCu | SnAgCu SnPb |
260°C | 260-270°C | |
| Advanced Linear Devices | ||||||
| Advanced Micro Devices (AMD) | 245°C | |||||
| Agere Microsystems | ||||||
| Agilent Technologies (was Hewlett-Packard Semiconductor) | Au matte Sn |
SnAgCu SnPb |
240-260°C | |||
| Allegro | 260°C | 260°C | ||||
| Alliance Semiconductor | matte Sn SnBi |
245-260°C | ||||
| Altera | matte Sn SnCu |
SnAgCu | SnAgCu | 245-250°C | ||
| American Technical Ceramics | SnAgCu SnIn SnPb SnPbAg |
250-260°C | 240-250°C | |||
| AMI Semiconductor | matte Sn | SnAgCu | SnAgCu | 260°C | ||
| Amphenol | Sn Sn over Ni |
|||||
| Anadigics | matte Sn | 260°C | ||||
| Analog Devices | Sn | 245-260°C | ||||
| API Delevan | Sn SnAgCu SnCu |
|||||
| Arcotronics | ||||||
| Arizona Microtek | ||||||
| Aromat | ||||||
| Artesyn | NiPdAu Sn over Ni |
|||||
| ATI Technologies | ||||||
| Atmel | PdAu over Ni matte Sn |
260°C | ||||
| Austria Microsystems | matte Sn | SnAgCu | ||||
| AVX | matte Sn | SnPb | 250°C | 260°C | ||
| Axicom | Sn over Ni SnCu |
255°C | ||||
| Bel Fuse | SnAgCu | 260°C | 260°C | |||
| BI Technologies | matte Sn SnCu |
260°C | ||||
| Bourns | Au over Ni | 245°C | ||||
| C&D Technologies | SnPb | |||||
| C&K | Ag Au Au over Ni matte Sn matte Sn over Ni |
255°C | 255°C | |||
| Caliber Electronics | SnAgCu | 260°C | 260°C | |||
| California Eastern Labs (CEL) | SnAgCu SnBiAu |
SnAgCu SnPb |
260°C | 260°C | ||
| California Micro Devices | SnAgCu | |||||
| Catalyst Semiconductor | Sn | 260°C | ||||
| Central Semiconductor | Matte Sn | 260°C | ||||
| Chipcon | ||||||
| Cirrus Logic | matte Sn | SnAgCu | SnPb | 245-250°C | ||
| Clare | matte Sn | SnPb | ||||
| Coilcraft | Au over Ni PtPdAg Sn SnAg |
SnAg SnPb |
260°C | |||
| Comtech Aha | matte Sn SnBi |
260°C | ||||
| Condor | ||||||
| Conec | ||||||
| Cooper Electronic Technologies | ||||||
| Copal Electronics | Au Sn SnCu |
|||||
| Corning Frequency Control | Au over Ni SnAgCu |
SnPb | 260°C | |||
| Coto Technology | matte Sn | SnAgCu | SnAgCu SnPb |
245°C | 270°C | |
| Cree Lighting | SnAg SnAgCu SnPb |
240°C | 260°C | |||
| Crystal Clear Technology | ||||||
| CTS | matte Sn over Ni SnAg |
260°C | ||||
| Cypress | NiPdAu matte Sn |
SnAgCu | annealing Sn thickness |
260°C | ||
| Dallas Semiconductor | matte Sn | SnAgCu | SnAg SnAgCu SnAgCuSb SnBiAg SnCu |
260°C | ||
| Dialight | ||||||
| Dielectric Laboratories | Au over Ni Ni Sn over Ni |
Ni thickness | ||||
| Diodes, Inc. | ||||||
| Diotec | 260°C | |||||
| Ecliptek | SnAgCu SnPb |
260°C | 260°C | |||
| ECS International | SnAgCu SnPb |
260°C | 260°C | |||
| Elpida | ||||||
| EM Microelectronic | ||||||
| Epcos | Ag AgPd Au over Ni Ni NiPdAu Sn SnAg |
|||||
| Epson | SnAg SnBi |
SnAgCu | SnAgCu SnPb |
260°C | ||
| ept | matte Sn over Ni | |||||
| Ericsson Power Modules | Au over Ni Pd over Ni Sn over Ni |
Ni barrier | SnAgCu SnPb |
245-260°C | ||
| ERNI | matte Sn over Ni | Ni barrier | SnAgCu SnCu SnPb |
260°C | ||
| Euroquartz | ||||||
| Everbouquet | ||||||
| Evox Rifa | Sn | SnPb | ||||
| Exar | matte Sn SnCu |
SnAgCu | annealing | SnPb | 250-255°C | |