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New Heat-Reduced Magnetic Solder Could Revolutionize Chip Design
A new heat-reduced soldering technique using magnets may lead to some revolutionary changes in the way chips are manufactured. Details are scant since the inventor seems to be playing it close to the vest for now in hopes of attracting chipmaker interest. "The result is a tin-silver alloy that contains a dispersion of iron particles tens of micrometers in diameter. When a magnetic field is applied to the solders, two things happen. First, the iron particles heat up, locally melting the solder. This localized heating, which works on the same principle as inductive stoves, remains completely contained, keeping the surrounding area cool. And second, the iron particles line up with the direction of the magnetic field, squeezing and pushing the liquid in that direction. This alignment is retained when the solder solidifies, and the well-ordered particles provide mechanical reinforcement that's greater than that afforded by a regular dispersion of particles."
How much iron are we talking about? Is this tantamount to having ferrite beads on all connections now?
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
From the article:
A new type of solder can be melted and shaped in three dimensions under the force of a weak magnetic field
How weak are we talking about here? I wouldn't want my chips to become desoldered just because they were exposed to an electromagnetic field. The article didn't mention any thing about that.
The result is a tin-silver alloy that contains a dispersion of iron particles tens of micrometers in diameter.
Not saying it can't work, as the above is light on precise chemistry, but in an alloy like this, you're bound to have atoms floating around... say, to the surface of the deposition... where it will oxidize. And something like OSP (which yes, wouldn't bond to SnAg) only lasts so long in storage... Don't we already have ENOUGH problems with solder joint oxidation? I look forward to seeing how this issue is addressed.
If I had a nickel for every time I had a nickel, I'd be richcursive!
JB Weld contains so much iron particulate in suspension that it responds to a magnetic field. If it weren't for the fact that the particles are so much larger and get drawn out of suspension and toward the magnet, it might be possible to speed-cure the stuff with this same trick.
"When a magnetic field is applied to the solders, two things happen. First, the iron particles heat up, locally melting the solder. This localized heating, which works on the same principle as inductive stoves, remains completely contained, keeping the surrounding area cool."
Quote from ScuttleMonkey, the Slashdot editor: "Details are scant..."
Neither the Slashdot editor or the writer of the linked article understand the physics. Magnetic fields cause something to heat only if the field is rapidly changing. Then the magnetic field causes everything conductive to heat, including iron particles.
When you bring a magnet near a PC, the damage is done to magnetic recording media, not the chips. Silicon is not generally sensitive to magnetic fields. This guy has managed to put a video game controllers, keyboards, and mice inside an MRI bore. If those integrated circuits can work in a 3T magnetic field, I'm pretty sure it can survive this new magnetic assembly technique.
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