New Heat-Reduced Magnetic Solder Could Revolutionize Chip Design 103
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."
Wait.... (Score:1, Insightful)
Comment removed (Score:4, Insightful)
iron, huh? (Score:4, Insightful)
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 [wikipedia.org] (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.
magnetic field? (Score:3, Insightful)
Not to be pedantic, but this is the Internet... They are applying magnetic flux to their solder, not just a magnetic field. A field doesn't impart any energy.
Re:Wait.... (Score:3, Insightful)
Once the solder melts, it should be possible to shape it using a refrigerator magnet -- molten solder simply doesn't have much viscosity or structural strength. You don't need to worry, though: melting it is done by inductive heating, which requires a strong time-varying magnetic field.
Re:"Magnetic sensitive components"? (Score:3, Insightful)
You're tellin' me! Two of the PCBs I designed use FPGAs, one of them a BGA package. It's quite the trade-off when choosing an oven profile that gets hot enough for long enough to melt the solder but not destroy the FPGA (stupid lead-free solder!). Lower temperatures would make our life a lot easier...