TCS Daily

Lead-Free Zeppelin

By Tim Worstall - July 10, 2006 12:00 AM

Environmental law and regulation is the only thing that will save the planet, don't you agree? We cannot let private interests, money-grubbing capitalists and uncaring fools ruin the planet for the rest of us now can we? We need those wise folks in government, the vote-stealers and their bureaucratic acolytes, to restrain and restrict such behavior so that our children can grow up in a pollution free world?

Despite the loaded (and hyperbolic) rhetoric of those three questions I'd actually agree with the principle. I'm not entirely convinced that Coasean bargaining can be used on every pollution problem and that there is, thus, a place for regulation, for green taxes if you will, helping to make explicit in the price system the external effects of people's actions. I'd even go further and support (a purely hypothetical) ban on certain activities: say, the wearing of excessively tight jeans by the overweight as a blot on the landscape that civilization can well do without.

However, and there always is a however, the value of such legislation and regulation does depend upon the competence of those actually writing them, drawing them up and passing them into law. If we were, heaven forfend, ruled by the credulous, incompetent and simply plain idiotic, then there is a chance (you can assign your own probability here) that we would end up with regulations that actually made the problem worse, not better. One would have to be more than a touch cynical to believe that we are in fact currently in that situation, that a talent for kissing babies on the campaign trail leaves the politician, shall we say, less than informed on matters environmental. To see whether such cynicism is in fact justified perhaps we should look at a recent piece of such environmental regulation and its effects and then make that judgment call: are we ruled by the credulous, incompetent and plain idiotic (or indeed all three)?

Case in point: Restrictions on Hazardous Substances (RoHS), from the technocratic masters of the European Union. Essentially, someone has got worried about the lead in electronics. When these are thrown away and thus end up in landfills there is a worry that this lead will leach out into the ground water and thus poison our grandchildren unto the nth generation. The solution? Ban manufacturers from using lead-based solder in making electronic items. This does, of course, have a cost attached to it. Everything, all courses of actions, have costs attached to them and our question should always be whether they outweigh the benefits. If they do then we are making ourselves poorer by following this course of action. If the benefits are greater than said costs then it might be an appropriate thing to do.

What might be the costs of removing lead from solder? Well, according to the Environmental Protection Agency (in a 472 page report) as Richard North points out: emerged that when the impact of mining and refining substitutes was taken in to account, the higher energy consumption in using the lead-free solders, which require higher temperatures, and all the other issues were factored in, the banning of lead - far from having a positive impact on the environment (and worker health) - actually had a significant negative impact.

That isn't really a very good start for our plan now is it? We'd like to solve an environmental problem and yet our proposed solution creates more environmental damage than the current situation. No, not a good start at all.

But why should this concern anybody outside the EU? If foolishness is alive and well in one part of the world it does not necessarily have an impact everywhere, does it? Ah, well, sorry, but the world is far too interconnected for that, thanks to globalization. Manufacturers will not run two separate production lines, one to make lead free products for the EU, another to produce for those less marked by environmental folly. Manufacturers across the world are converting to solders which do indeed pass these new rules. Which is in itself something of a problem because of an interesting bit of metallurgy: tin whiskers. (OK, OK, interesting is a relative term I agree.) As Electronic News reports:

Tin whiskers can be reduced, but it's doubtful they will ever be eliminated once lead is completely removed from solder.

Why is this a problem?

With the European Union's Restriction of Hazardous Substances (RoHS) legislation scheduled to take effect on July 1, and other countries such as Korea, China and parts of the United States scheduled to follow suit in coming months, lead-free solder has become a requirement for many industries. The problem, however, is that a suitable replacement has not been found so far. While whiskers probably won't be a problem in consumer electronics, where product life is short, over time they can grow and short-circuit devices.

Just to make this clear: tin whiskers, which no one actually knows how to stop forming, will mean that electronic items will fail if we don't use the lead based solders. This will, we have to assume, make the environmental problems even greater as those failed products will be sent off to the landfills and new ones manufactured. Odd to think of legislation that deliberately imposes planned obsolescence upon us.

In fact, the new regulations could mean even more lead used in solder, not less. (This is due to an entirely boring bit of metallurgy, in that there are only a few mixtures of lead and tin that work as solders, so called eutectic alloys. No, you don't want me to explain that here.) As PCB 007 explains:

After 2 years of seriously trying to comply with the RoHS provisions against lead in solder, the Swatch Group plans to return to lead, either high 90% -- sanctioned by RoHS or low 37% -- banned. The reason is tin whiskers, "generating short circuits which end the watch's function."


How did it happen that the EU who wants to ban lead in solder, permitted 90% lead and not 37% lead or 10% lead. Well, the answer turns out to be that IBM's C4 flip chip technology requires the higher eutectic temperature of the higher lead containing alloy to prevent it from reflowing.

So now our regulations really are looking just a touch strange. In order to solve a problem we're going to increase the amount of energy and resources necessary to manufacture the various electronics upon which the modern world depends. The new methods imposed, enforcing the absence of lead, mean that those electronics won't actually work for very long. Then, just to introduce some farce, the only way to make reliable electronics will be to use more lead than before, lead being that evil product we're trying to get out of the system.

Perhaps my cynicism about the competence of our rulers is in fact justified? That they really are credulous and capable of idiocy? No, no, surely not! Those in power are wise and just! They have only our best interests at heart, they would never do something so contrary to our interests!

One further snippet of information. Remember what started this whole thing? The idea that lead would leach from landfilled electronics into the groundwater and poison the grandkids? More expensive, more unreliable, electronics manufactured at a greater cost to the environment, justified by that one worry that lead leaks from waste sites. Only it doesn't.

A year-long study by the Solid Waste Association of North America (SWANA) Applied Research Foundation, released in March 2004, concludes that heavy toxic metals, including lead, do not pose an existing or future health threat in municipal solid waste landfills.


"The study presents extensive data that show that heavy metal concentrations in leachate and landfill gas are generally far below the limits that have been established to protect human health and the environment."

Apologies, but no, I'm afraid that I don't think I'm being too cynical. It really does appear that we are ruled by the credulous, incompetent and sometimes simply plain idiotic. Happy days, eh?

Tim Worstall is a TCS Daily contributing writer.



Yet another confirmation of the law of unintended consequences
This law is derived from a fundamental principle of human interaction: Irony increases. Other corollaries include Murphy's Law and the Peter Principle.

No Whiskers On These Balls
April 9, 2006

Dear Dr RoHS,

Can unleaded BGA solder balls potentially grow tin whiskers as tin plated leads do? Annealing seems to be the standard approach for pure tin plated lead devices, but what about BGAs?

Are unleaded BGA joints as reliable as leaded? I hear all sorts of problems after n thermal cycles and that they are brittle.

David Cooke
Surrey Satellite Technology



Even tin-lead solder can potentially grow tin whiskers. It has, but it is extremely rare. So tin-inclusive lead-free solder balls cannot be guaranteed free from the possibility of tin whiskers.

However, I phoned around and NO ONE I ASKED REMEMBERS HEARING OF A LEAD-FREE SOLDER BALL GROWING A WHISKER. Lead-free and lead-inclusive joints are differently reliable, neither being superior in all circumstances.

Lead-inclusive solder might have an edge with large BGAs under fast thermal cycling as it is more flexible than lead-free, and I have recently heard rumours - which I cannot substantiate and know no more of - regarding lead-free joint reliability under drop testing.

You may have to organise testing aimed at your particular environment. If you are already using that particular BGA in lead-inclusive form, do you need to change?

I would be interested in feedback from readers who have had reliability problems with lead-free BGAs on otherwise reliable assemblies. Or from anyone who knows more about drop test reliability.

Dr RoHS thanks and

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