“Maybe it is worth adding,” said one expert who prefers to remain anonymous, “that whisker diameters range from 0.1 um to 10 um, while the diameter of a human hair is 70 um to 100 um — so the largest whisker is only some 15 percent of the diameter of a thin hair, and most are less than 5 percent. A good fraction (of these are) so thin that light waves just pass them by, scattering a bit but not reflecting. So the optical microscope images that (typically used to illustrate whiskers) show only a small fraction of what is really there. Scanning electron microscope (SEM) images are a bit better, but only show a small zone of the sample; also, not many folks are able to acquire SEM images of their equipment. So all too many folks have the idea that whiskers are something that happens to someone else, but never to them. This is an expensive misconception.”
The latest Bob Cringley column raises some concerns — but on a topic that I cannot assess for validity. If Bob is correct we will experience much higher electronics failure rates than we have come to expect — due to regulations mandating the abandonment of tin-lead solder for substitutes such as tin-silver or all-tin solders. If you wish to know a bit more about such defects as tin whiskers, the graphic at left is from the Wikipedia page on the EU “Restriction of Hazardous Substances Directive” or RoHS.
…Which brings me to you, or rather to all of your soldered devices that are two years old or less. Most of these are now assembled using solder joints that have no lead in an effort to save our groundwater and our health. The fact that the lead has been generally replaced with silver or bismuth, both of which are actually greater health risks than lead, well we’ll leave that one for Ralph Nader if he decides not to run for President. The longer-term trend is toward all-tin connections, anyway, but they don’t work very well, either.
I wrote a column about this back in 2004 (it’s in this week’s links) that was heavy on information and therefore low on readership. Everything in that column has come to pass and more. Where’s my Pulitzer Prize?
Costs have gone up, mean time between failures (MTBF) has gone down (accelerated MTBF tests, which are the only MTBF tests we do anymore, don’t reliably pick this up, by the way), and reliability has suffered. Since we don’t fix things anymore, it’s hard to say whether your gizmo failed because of bad solder or not, but the problem is becoming worse as a greater percentage of total circuits in use have lead-free solder. The military was especially concerned, even before the whisker crisis.
We’re talking about tin whiskers, single crystals that mysteriously grow from pure tin joints but not generally from tin-lead solder joints. Nobody knows how or why these whiskers grow and nobody knows how to stop them, except through the use of lead solder. Whiskers can start growing in a decade or a year or a day after manufacture. They can grow at up to nine millimeters per year. They grow in any atmosphere including a pure vacuum. They grow in any humidity condition. They just grow. And when they get long enough they either touch another joint, shorting out one or more connections, or they vaporize in a flash, creating a little plasma cloud that can carry for an instant hundreds of amps and literally blow your device to pieces.
…Maybe dumping lead solder was absolutely the right thing to do. Maybe it was absolutely the wrong thing to do. The truth is we haven’t the slightest idea the answer to that question and anyone who claims to know is wrong. We didn’t know what would happen when we started this and we don’t know what we’ll get out of it, either, or whether it will be worth the cost. All we know for sure is that a bumpy ride lies ahead.
Note Bob Landman’s comment to the Cringley post. Landman represents he is with H L Instruments, and writes as if he is an industry insider.
…The article is dealing with another problem of lead free solders, the brittleness of the joint. In high mechanical shock applications (like a missile) or high vibration (automobile electronics) the lead-free connections are not reliable. Tin-lead solder is a “soft” joint that resists cracking. This improvement in SAC alloys may solve the problem but it sounds like its years away from being a product we can use. What do we do until then? Do you want your pacemaker to fail? The FDA already recalled a pacemaker that failed as it’s timing oscillator shorted due to a whisker. The SWATCH watch company lost over $1B on watches that failed (and they got themselves a nice special exemption from the EU so they could go back to tin-lead solder).
Tin whiskers will still grow ABOVE the point on the electronic components where the lead-free SAC solder alloy does not wet the tin. Look at a solder joint - see for yourself what I mean. In order for this to be a solution to tin-whiskering, all electronic components must have their leads (and BGA parts their solder balls be this SAC alloy.
I have seen nothing in the literature nor from colleagues that suggests this will be done.
The industry forgets again the lesson learned in 1942 when cadmium plated tuning capacitors shorted in aircraft radios, in the 1950s when zinc plated computer floors shed whiskers and blew computers, when tin plated relays in the 1950s shorted relays in AT&T phone switching centers.
We seem to have to re-learn again and again what metallurgists know, that pure tin, zinc and cadmium platings grow whiskers.
The NASA Electronic Parts and Packaging Program [NEPP] website has an extensive area devoted to research on the general problem of tin whiskers. What I’ve read there is not reassuring. An example of the papers referenced is Metal Whiskers: Failure Modes and Mitigation Strategies from December 5, 2007.
I’m relieved that all of ADAGIO’s navigation electronics date from circa 2000, before RoHS :-) I’m not concerned about failing iPods, but I would not like to read FAA post-mortem reports of airliner crashes. Is this a “time bomb” sort of problem? Danged if I know — if you have solid information, please give us some light in the comments.
I can vouch as a apple tech support person in london to the high failure rates on electronics coming through for macintosh laptops, 3 problems on different model apple laptops all related to lead free solder within the last four years.
ibook G4 800-1ghz video chip motherboard failure proven by danish trading standards (no recall)(overheating solder failure)
ibook G4 1.33 12″ airport card mounting socket contact failure (no recall)
ibook G3 500-800 large motherboard failure rates due to pb free solder.(warranty extension for repairs)
I just had my own motherboard replaced in intel core duo laptop due to heavy 3d gaming causing the graphics to slowly die due to heat issues deforming contacts within the chip.
basically lead free solder has a much worse impact than lead solder, because lead free solder manufactured products die so early theres a huge waste technology issue created by landfilling 3-4 year old computers that might have had 9-20 year long functional lives if made with lead solder. The customers looses and the environment looses, while the manufacturers can brag their green credentials and get sell us new laptops in record time, notice how the military were exempted from forced lead free solder. basically the green movement needs to get its facts right now, as to which is worse ?
Thanks heaps for your first hand report.
Difficult question: can you estimate what the per model failure rates are due to lead free solder? E.g., iBook G4 family?
It’s a bit depressing that there seems to be no media interest in this issue. Possibly because it’s not politically correct to question “green regulations”?
Interesting that a tech support person says otherwise, but Apple’s official stance on lead-free is that they’ve had no increase in failure rates since moving to RoHS back in 2004!
This is not a simple issue, but Dr. Lansky of Indium reports that reliability has improved for Motorola after the transition and the lead-free formulations allow them to use tighter spacing making their smaller phones a reality.
http://www.indium.com/drlasky
As for Swatch and other “tin-whisker” issues, many result from using pure tin plating — not the new RoHS formulations. Pure tin plating has been known to be an issue long before RoHS.
Millions of products are compliant and have been for years. If some of these doom and gloom predictions were true, we’d know by now.
Marc - thanks for comments and some reassurance. Dr. Lasky is a good source I didn’t know about.
Lasky is wrong. He is not a good source of information on tin whiskers, NASA is “the” best source as is a aerospace industry group that I participate in to learn the facts.
There is NO, repeat, NO reliable substitute for lead in solder yet - if there was I’d be using it and so would all aerospace and medical device makers. And the EU would not have exemptions for the use of tin-lead solder for high reliability products, would they? Of course not.
Lasky is using a false straw man analogy when he states that “millions of products are compliant and have been for years. If some of these doom and gloom predictions were true, we’d know by now.”
No, we would not. The cost of analysis is very high (as much as $3000 per failure) to do the analysis. When your PC fails, what do you do with it? You can toss it (excuse me, recycle it) or you can take it to a repair center like BestBuy. And what do you think they do with it? If there’s a board problem, they replace the board. Period. All lead free products need do is to get past the 1 year warranty period and they are home free. Any no-lead manufactured product has a very high probability of doing just that, millions do (as Lasky says). Getting past 3 years is another matter. Do you want to buy a new HDTV in 3 years? How about a new car? What do you do when 3 years from now you are driving along and suddenly the car stops (30% of automobiles today is electronics and fortunately thus far the auto industry is still (at least that’s what BMW claims) using tin-lead solder. Even if they do, can they continue to get parts that are not pure tin plated? How do they know they receive parts that are tin-lead plated? NASA knows that 3-5% of the parts they get have no lead in them. They have to do lot inspection using XRF (X Ray fluorescence).
Also, it depends on the temperature and humidity and a lot of other factors as to how fast tin whiskers grow. Just go to the NASA whiskers website and read the facts for yourself. I’m not making this stuff up; I’m reporting the facts. I remain very concerned about this problem.
Lasky wrings his hands with great worry about third world recyclers - that’s why he wants the lead out of solder. I worry about friends and relatives who have implanted pacemakers that end up being recalled. Medtronic had such a FDA recall.
How is it sensible to make electronics less reliable, so there will be many times more electronics failing sooner, to recycle? This will create a larger and larger third-world recycling industry, many more people recycling discarded electronics, and even if the statistic of “accidents and injuries per ton of electronics recycled” stays flat, we will have increasing accidents [what does “safety” mean in the context of recycling, anyway?
Do the third-world recyclers eat a percentage of what they disassemble? we should make our electronics taste bad, to discourage accidental ingestion…] and these increasing accidents will then be attributed to…what? The percentage of silver in the electronics? Something else with no scientific basis? Union labor?
The real solution is to reduce the amount of electronics to be recycled, and that will make it safer.
Thus, we should make more reliable electronics. Lead in solder has been proven to reduce mechanical-shock-failures of BGA solder joints by one to two orders of magnitude, as well as prevent whiskering.
The third-world people are not going to change HOW they recycle our junk electronics, so reducing how much junk we send them reduces the number of people employed in that electronics-recycling industry, and accidents go down, even if accidents for accidental ingestion of electronics.
Further, disassembly of electronics containing pure tin will inevitably result in inhalation of tin whiskers freed from the electronics assemblies during disassembly under third-world conditions; thus, lead-free electronics actually pose a new health-and-safety risk to third-world disassemblers that was not there in the pre-ROHS days.
I urge Lasky (and others so worried about recycling) to take a stand in eliminating this health risk to electronics disassemblers by advocating the use of tin/lead-plated electronics components which will not grow these hazardous tin whiskers.
I’m with Bob. As for Lasky, I recommend that he join the Peace Corps and spend two years sitting on a rubbish-heap of our junk electronics, helping those third-world folks to recycle better, recycle more safely and recycle more productively.
Then and only then, when he returns to this country and talks about recycling junk electronics, might I consider that he knows whereof he speaks.
For decades (not enough) folks have had on their car bumpers, stickers that say, “Question Authority”. If more people had taken that advice, we would not be in the thirty-plus-billion-dollar hole we are, with satellites and nuclear reactors hiccuping and dying.
The entire “lead in electronics is awful” movement was a foolish idea in the beginning, born of no science whatsoever. The exact origin of the RoHS campaign would surely be an interesting story, but here we are today, in the middle of another fine mess. Millions of people agreed with a foolish idea, because someone told them to agree.
Just because millions of people do a foolish thing, does not mean that it is not a foolish thing.