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Melting Microchip Defects May Extend Moore's Law
schliz lets us know about research out of Princeton on melting away defects on microchips using a laser. The new technique, termed Self-Perfection by Liquefaction (SPEL), was published in the May 4 issue of Nature Nanotechnology. Researchers have traditionally approached chip defects by trying to improve the microchip fabrication process, but this eventually reaches fundamental physical limits to do with random behavior of electrons and photons. By focussing on fixing defects, the new method enables more precise shaping of microchip components, and engineers expect to dramatically improve chip quality without increasing fabrication cost. The before-and-after images are remarkable. Here's a diagram of how the process works.
Whew yeah, those are amazing. World-changing, even.
What am I looking at?
Where do the frikin' sharks come in to it?
Is crushing a suspect's child's testicles illegal?
John Yoo: "No, [if] the President thinks he needs to do that."
here is a larger version
here... http://www.princeton.edu/pr/pictures/a-f/chou/Chou_micrographs.jpg
better link: http://www.princeton.edu/pr/pictures/a-f/chou/
I was imagining a laser doing touchups on really bad places of the chip to remove shortcircuits and stuff like that. But this seems like another step in the process of making chips.
A bit like drying pulp to get paper.
Scientists really need to stop using lasers to fix microchips and start using them for something practical.
For instance, death rays.
How much funding do these people get ?
... the original was bigger than 162 x 169 pixels also ;-)
It's obvious they've just used the BBC testcard and Photoshopped out the girl, clown and blackboard.
http://www.bbc.co.uk/cult/classic/classic/images/640/testcard.jpg
Stands out a mile, obvious fake
As I understand annealing it removes internal stresses created by uneven heating and cooling. This process smoothes etching or deposition defects.
Nothing in the world is more dangerous than sincere ignorance and conscientious stupidity.
"Whatever made you ask this question?"
People generally ask questions to get answers. You, however, seem to ask questions to make other people feel stupid.
I'm a materials scientist, so hopefully I can explain this quickly for you all :)
:)
The images that are given (before and after) are some scanning electron microscope images. Think optical microscope except with electrons. Anyway, there is a serious improvement in the structure - the edges are a lot cleaner and more defined. This is a really simple and beautiful way of letting Nature do the hard work for us. What this is doing is liquifing the material and letting surface tension pull it into the lowest-energy configuration (least amount of surface area locally).
It's really a neat way of doing it, because fabrication is really tough - uses either chemical etching or some method of particle bombardment to remove atoms. There's a big trend in matsci to build down, and build up, at the same time at the nanoscale. Think of this as the "error-correction" process after fabrication.
--This is not the same as annealing - annealing is a solid-state process, putting energy into the material to enable atoms to move and remove stress and other small defects from the material.
Hope that helps
It gets hot and the defects get smoothed out.
I'm pretty sure that annealing changes the microstructure of a piece of metal (it doesn't change the form at a macro scale, but the internal structure changes), and the changes that this process makes seem to be occurring at a similar scale to recrystallization.
As far as why, I think it's interesting to look for parallels in the cutting edge of technology and ancient trade craft.
Nerd rage is the funniest rage.
They spelled liquifaction correctly.
Finally, the CS way of developing is extending to other areas.
Soon architects will quickly make ten buildings without much previous study, then sell those who don't fall in the first two weeks with the promise that if some fall in the first five years, they'll release a v2.0 shaped as the ones still standing.
I can almost see the changelog:
"v1.5.1142 - The coming of winter discovered a weakness against rain in paper roof. New ice roof installed."
When fabricating chips, yes, you do want nice clean lines. Whopeee for clean lines. All hail clean lines. By coincidence, surface tension works towards cleaning up lines. Somebody should have patented surface tension. Too late now.
But eventually the nice clean lines end up at a transistor or resistor. There the rules are very different. You don't want surface tension to do its thing on the end of the line, which would be to shorten it. Very conveniently these nice pictures don't show what happens at the end of each line. How convenient.
Then you're much more forgiving than most people.
If a chip is designed to run at a certain speed, but manufacturing flaws make it run slower, then it a very real sense the chip didn't work. The fact that it still is possible to use the chip for some things doesn't mean that it's not broken.
I once rode home a bike that had one of the pedals broken off. It took longer than usual, because I was travelling at a lower speed, but by your definition my bike didn't have a defect. In my opinion, a missing pedal is pretty darn broken.
One time I threw a brick at a duck.
The issue is that in smaller conductor fabrication sizes the little wiggles do make a difference. The flaws in fabrication causes small variances in current and electrons to 'leak', this makes fabricating a 45nm chip so much harder then a 90nm chip. So by straightening the conductors you can make that 45nm chip easier to produce reliably, and also push the boundaries to make even smaller chips.
One of the major problems with getting linewidth (and thus line separation) down in the photoresist process is the problem of dielectric breakdown. Charge builds up at the irregular surface and if two points on different conductng lines are near one another they will arc across and the chip will be useless (same reason arc lamp electrodes are shaped as needles). This process seems to remove the irregularities, which should allow chip fab units to lay down pathways closer together. Note even the square spots get round(liquids form spheres to reduce surface area) which reduces the tendency for breakdown to occur. If nothing else could allow for the use of lower dielectric packaging, and make things cheaper.
Really cool.
quote from article:
Simple melting by direct heating has previously been shown to smooth out the defects in plastic structures.
This process can't be applied to a microchip for two reasons. First, the key structures on a chip are not made of plastic, which melts at temperatures close to the boiling point of water, but from semiconductors and metals, which have much higher melting points.
Heating the chip to such temperatures would melt not just the structures, but nearly everything else on the chip. Second, the melting process would widen the structures and round off their top and side surfaces, all of which would be detrimental to the chip.
Chou's team overcame the first obstacle by using a [...] laser [...] because it heats only a very thin surface layer of a material and causes no damage to the structures underneath. The researchers carefully designed the pulse so that it would melt only semiconductor and metal structures, and not damage other parts of the chip. The structures need to be melted for only a fraction of a millionth of a second, because molten metal and semiconductors can flow as easily as water and have high surface tension, which allows them to change shapes very quickly.
That's pretty amazing, that the semiconductor and metal self-correct via surface tension, and by using a directed laser pulse so you only affect specific areas of the chip.
This isn't a matter of detecting defects and fixing them. It is a matter of applying a finishing step that improves the whole chip at once. You can be sure than chip manufacturers try very, very hard to get things right the first time. But if you read the article you would know that there are basic physical processes that make a certain amount of randomness and jagginess inevitable, which the laser process fixes.
What about CowboyAnnealing?
One of my dozens of hobbyist hats is my glassworkers hat and annealing is a big deal in glasswork. From my experience with glass, I would say that annealing is probably the wrong term because this involves an actual deformation. Typically in annealing you want to stay below the point at which deformation occurs and your main concern is to create a gradual change in the temperature over time in order to eliminate internal stresses. So that's probably not the best word to use in this case since this is not about alleviating internal stresses but actual changes in the shape of the product.