The Tin-Whisker Menace

An anonymous reader writes "Fortune has an article about how the recent environmental push to completely eliminate lead from electronic components and wiring may eventually lead to the next Y2K problem of slowly-growing tin whiskers short-circuiting equipment.""

Comments

It's those idiot greens again

[PedanticSpellingTrol]

This probem is one of the reasons we use lead in solder, it's only reappearing now that the EU is pushing for all new electronics sold to be lead-free. Frankly, I'd like to see everyone keep using lead and just stop selling to europe. That'll teach 'em.

Re:It's those idiot greens again

[Space Coyote]

Yeah, they'll have to replace some electronic equipment now and then, perhaps. And all because they don't want to poison themselves with lead. Silly Europeans.

But you go, USA, put lead back in everything, just to be the rugged individualists you are and show the rest of the world.

Hell, do you think Ancient Rome would have taken any crap from anyone else criticizing them for their lead pots? Exactly. USA! USA!

Re:It's those idiot greens again

[Vegeta99]

it's more disposal than consumer protection... tons of lead in a landfill isn't good

Re:It's those idiot greens again

[jmichaelg]

I hired a contractor to remodel my kitchen a few years back. I did some of the easier jobs such as wire the switches and plumb the sink drains. I was putting together a list of parts I'd need for the sink when the contractor told me the following story about a new development on the north side of town.

The plumbing inspection happens before the sheetrock goes up so any plumbing errors are easy to spot and repair. The permit inspector was on the last house where the plumbers were just cleaning up. The inspector spotted a discarded solder can and picked it up. As he handed over the empty to one of the plumbers, the inspector said,
"Boy that solder is really good stuff!"
To which the plumber said, "Yeah, it's a little more expensive but it flows really smoothly."
The inspector replied, "It must be the lead that makes it flow so smoothly. But you know, it's too bad that you're not allowed to use lead solder any more. You're going to have to start over." And with that, the inspector ticketed every house in the subdivision.

I ended up using plastic plumbing.

Re:It's those idiot greens again

[amembleton]

Tons more lead free electronics isn't a good thing for a land-fill either. If electronic devices, don't last as long then more will be dumped onto landfills, albeit leadfree.

Re:It's those idiot greens again

[trburkholder]

OK, I'll feed the troll.

Lead is a neurotoxin; children exposed to lead are at risk of developmental delays, reduced IQ, learning disabilities, hearing loss, reduced height and hyperactivity. Levels above 10 mcg/dL (about 100 ppb) are considered to be a health risk to children. Adults are at risk of anemia, nervous system dysfunction, kidney problems, hypertension, decreased fertility, and increased level of miscarriages.

It used to be that the biggest source of environmental lead was automobile exhaust, followed by lead paint. In the late 1970's 14.9 million children in the US had elevated blood lead levels. This figure declined to about 300,000 in the US CDC's 99-00 survey. Banning lead paint in 1978 and leaded gasoline's phase out starting in 1975 removed the sources of exposure.

In adults, levels above 24 mcg/dL are considered elevated and mostly come from workplace exposures, such as demolition, recycling and manufacturing. The number of adults with elevated blood lead levels has also been declining.

The problem with adult exposure is that without proper industrial hygiene, the lead comes home with them, providing a route of exposure to their children. 2-3% of children with elevated blood lead levels are exposed in this way.

Lead in manufacturing is an expense since exposure has to be managed. But, if you don't control it at the source, then you have to try and manage it in the waste stream which is much more expensive and difficult. Given the population density and the emphasis on recycling in the EU, lead exposure through this route is a decreasingly acceptable risk to the population.

P.S. The EU is the largest economy in the world so you tell your directors that you don't need that market anymore!

No

[Sycraft-fu]

All other factors aside, the reason that Y2K would have been the problem that some alleged is that all the failures would happen at the same time. If something fails, even something major like a powerplant, it's a problem not a catastrophe. It would only be a catastrophe if lots of tem, or worse yet all of them, failed at the same time.

So supposing this problem is as stated, it'll just lead to higher failure rates of electronics. That's not a catastrophe, just something we'll have to deal with, either by changing the methods used or simply by increasing the rate at which we replace devices.

Tin whiskers eh?

[bildungsroman_yorick]

Obviously to fix the problem we need some amalgamation of courage and heart in electronic form pronto. Is there any engineers here whose work includes hiding behind curtains and appearing to his co-workers in giant green mask form?

Re:I don't get the connection

[InternationalCow]

I quote from a most informative pdf (get it here):
"A tin whisker is a single crystal of tin that grows spontaneously from a surface a pure tin. They are typically only a few microns (?m) in diameter but can grow to lengths of more than 10 mm (though lengths on the order of 1 mm are far more common) [NIST Website, 2002]. Tin whisker growth is spontaneous, not relying on external influences of current or electrolytic action, more commonly associated with mechanisms like "dendritic" growth, conductive filament formation and electromigration. While early studies believed that tin recrystallization (which occurs at 50 deg C) played some role in whisker formation, recent studies have reported as much, if not greater, propensity for whisker formation at temperatures as low as room temperature [NASA Web Site, 2002].(....)Conventional wisdom attributes tin whiskering to internal stresses in the pure tin layer, with a primary source being the compressive stresses caused by electroplating. However, tin whiskers have also been reported from surfaces where tin has been applied by methods other than electroplating. In the presence of compressive stress, whiskers are extruded over time, as a stress release mechanism. Many factors may contribute to the stress in the plating, including intermetallic formation, thermal expansion mismatches, corrosion of the substrate, and externally applied forces such as bending, lead forming and application of pressure. Defects such as scratches and nicks have been reported to magnify the effects by causing local stress concentrations and possibly providing openings in any protective surface oxide layers. In fact, these external factors may cause whiskering in samples that may otherwise be resistant to the phenomenon. For example, tin whiskers have been observed to form on tin finished surfaces that had been exposed to hot oil dip to fuse the tin (a known mitigating process) [Cunningham and Donahue, 1990]. Adding a trace amount of another element (i.e. Pb or Bi) has been shown to reduce the tendency of plating to grow whiskers."

Mah cat has tin whiskers

[BadDoggie]

Oh wait, mah mistake. He has twailve.
</drawl>

woof.

wither the tin-foil hat?

[close_wait]

This is just a government conspiracy to bypass tin-foil hats! Everyone knows that it's the 2% lead content which actually blocks the mind-control rays....

Re:I wonder...

[notany]

This is whre progress is going. For example Prof. David Patterson (inventor of RAID and first MISC instruction set computers) has been trying to do this many years. See IRAM

There is some practical problems.

1. Low yield. Failure rate grows with bigger chips. Makes them more expensive.
2. Harder to make. Different prosesses for making memory and logic (this has been done already of course).
3. Heat problem. It's easier to cool separaate chunks of prosessor, graphics processor and memory.
4. Upgrading. New usb spec, make new mask. Upgrade graphics prosessor, make new mask. New mask for every memory configuration. Uh.

We may get close eventually. Practicality may dictate that we end up with 1-3 chips per home PC. Maybe optical connections between.

My time estimate for this to happen is 10-30 years from now.

Heavy Metal!

[Nikkodemus]

Oh man, this song could be sooo big!

Tin Whiiiiiiiiiskers
They cancelled IT Class
Tin Whiiiiiiiiiskers
They come from Satan's ass..

Hairs of the Devil, items of no good repute
If the grow to a certain lenght, the PC's can't compute!

Tin Whiiiiiiiiiskers

(guitar solo)

(reprise)

Forget tin Whiskers, Nanotechnology will kill.

[d3nali]

The issue with tin whiskers is that they are so small and invasive. Next to this problem however nanotechnology will make it look trivial.

The small particles being produced with nanotechnology concepts will enable it to invade and affect the body in ways that connot possibly be handeled by todays technology or our immune systems.

I'm all for technology but we need some protections before a company starts spewing these waste/production nanoparticles off into the enviroment in order to save in producing costs for that lastest flat screen tv using carbon nanotubes.

Temperature cycling

[NoseBag]

When I worked in the E-Warfare division of (deleted) we ran into this issue whenever we used brass prototype packages to house circuits. The cause of the whisker growth (in brass) was the repeated temperature cycling (TC) of the package. Apparently in the presence of the TC, the tin in the brass preferentially crystalized out of the brass in whisker form and pushed out of the sides. Kinda neat, actually, except for the occasional power supply short. We found that a solid nickel-plate or copper-plate fixed the problem nicely.

Let's talk reality here

[Sycraft-fu]

The lead in solder accounts for a very, VERY tiny percentage of the lead we use and dispose of. It's a really stupid thing to be targeting since there are much bigger problems. It's like worrying about a basket of dirty laundry when your entire floor is covered in garbage. You aren't fixing a problem worth solving.

Now these tin whiskers aside, this sucks for people who like ot do electronics work at home. The only solder blends that are easy to work with contain lead. A 63/37 Sn/Pb or 62/36/2 Sn/Pb/Ag blend is what you need for a low melting point and nice, clean, easy application. The non-lead solders are much harder to work with since they need much higher temperatures. Easy to burn out a component if you aren't careful.

Now compare the amount of lead I use to make an electronic device (like 25-30% of a tube the size of my pinky, that's less than 40% lead and wound such as to use less than 30% of the space in the tube) to a lead-acid car battery, which all cars have and are replaced about once every 5 years.

The no lead in circuts is a wonderful example of environmentalists going after a non issue and fucking things up for people. Yes, lead is a problem, it can contaminate water tables and lead poisoning is NASTY. However the small amount of lead used on PCBs is NOT the problem, and getting rid of it just creats MORE waste by creating electronics that die faster.

Re:Let's talk reality here

[Waffle Iron]

The lead in solder accounts for a very, VERY tiny percentage of the lead we use and dispose of.

It seems to me that the whole lead issue is addressed very erratically. The solder in a circuit board is a huge problem, but anybody can go down to Wal-Mart and buy a tin of airgun pellets containing about a 1/4 pound of pure lead and spray it all over their back yard. Lead encased in computer monitor glass is a huge crisis, but nobody talks much about 36-inch TV tubes, and if you shop for wine glasses some of them brag about the the fact that they contain 24% lead.

It seems to me that all the focus goes on new types of products, while many old products that use lead are ignored.

Re: I wonder

[EvilMidnightBomber]

Top ten list of critique openers most likely to get you prematurely killed by an engineer

10. I wonder...
9. I was just thinking...
8. That's great, but what I was really looking for was...
7. You know what would be really cool...
6. Was it supposed to do that?...
5. I'm sure it'll look better by the time you've finished...
4. Would it be possible to...
3. To: Engineering From: Marketing Priority: Urgent
2. Did someone tell you to do it this way?...
1. How hard would it be to...