By Terrence E. Thompson, Senior Editor

It seems doubtful whether our little animal friends (or indeed, humans) will benefit from the electronics industry's conversion to Pb-free materials.

"Much ado about nothing," as Shakespeare once wrote.

Globally, electronics manufacturers are forced to go "lead free," even when it provides no tangible benefits except a "feel good" reaction for the ill-informed, pandering bureaucrats and the technically-illiterate public.

Lead free has, undoubtedly, raised the cost of electronics manufacturing with no discernable documented environmental benefits while raising reliability questions. This wasted money could have been better spent figuring out how to make more efficient transistors that dissipate less heat-but that would make sense.

Environmental Impact?

Joe Fjelstad of SiliconPipe, San Jose, and many other notable industry veterans, have sought-even demanded-documented proof that any electronic product's solder joints have ever leached lead into the environment. The result? They are still waiting!

Lead additives have long been removed from gasoline and paint, two major legitimate health hazards.

My pet peeve is the global pandering to the lead-acid battery manufacturers. When dumped in landfills, batteries account for more than 90 percent of the lead getting into the environment. Yet, politicians gave them several decades to clean up their act. Puzzling, indeed.

What Experience Base?

In the pre-PC (politically correct) days, electronics manufacturers had decades (actually centuries) of tin-lead soldering experience to draw upon.

The result? We had material sets that worked exceptionally well with known reliability data, something that is sadly lacking with most new, "lead-free" alloys.

My old friend Joe Keller-with decades of soldering data that he and his engineering teams originated at Martin-Marietta and later Motorola-knows eutectic tin-lead soldering well.

Joe showed me, on a visit to his Motorola lab in Fort Lauderdale several years ago, that eutectic tin-lead solder had incredible component lead-to-PWB-pad bonding strength and electrical conductivity, which, in part, made Motorola's Six Sigma mantra possible.

The requirements were simple: if the metal pads and component leads were chemically clean (fluxed) and pre-tinned, something Motorola paid a little extra for, then the reflow process provided incredible yields.

EPA Concerns?

Although it is difficult to follow all of the USA Environmental Protection Agency's directives and rulings, it would appear that the truly hazardous aspects related to the use of tin-lead solder have been addressed. The fumes and waste discharges from plating operations and soldering itself are controlled-or controllable.

Lead-free solder alternatives are a different issue. Some use metals and alloys long known to cause reliability or health issues. It will be interesting to see what a few decades of lead free do to enhance the environment or electronics reliability.

In fact, lead-free solders are not up to the task in certain supercomputers, and since they are needed for many purposes, including analyzing global environmental changes, certain classes of supercomputers have been granted lead-free exemptions.

Real-World Reliability Problems

The higher temperatures required for lead-free soldering typically cause PWB delamination and/or warping due to the epoxy's glass transition point being exceeded. When one attempts to solder bumped chip packages to these non-planar substrates, the odds are against a uniform bump contact. The widely used (and understood) FR4 boards are not up to the task.

Lead-free also makes fine-pitch soldering somewhat problematic.

So why the lemming-like rush over the lead-free cliffs? Beats me!