Slashdot Mirror
Research Discovery Could Revolutionize Semiconductor Manufacturing
New submitter arobatino writes "A new method of manufacturing semiconductors which eliminates the substrate (in other words, no wafer) could be much faster and cheaper. From the article: 'Instead of starting from a silicon wafer or other substrate, as is usual today, researchers have made it possible for the structures to grow from freely suspended nanoparticles of gold in a flowing gas. "The basic idea was to let nanoparticles of gold serve as a substrate from which the semiconductors grow. This means that the accepted concepts really were turned upside down!" Since then, the technology has been refined, patents have been obtained and further studies have been conducted. In the article in Nature, the researchers show how the growth can be controlled using temperature, time and the size of the gold nanoparticles.'"
That is like 1950's technology levels. A long time before they can make million gate devices.
There are many many problems associated with replicating sub-nanometer scale patterns on a ground flat substrate. If they don't have a planaer substrate they are going to have lots of problems creating the required imaging patterns. Note that at the current scales you can't print a | object as a simple | you have to make it look like an I, essentially doing what is called dog-boneing because of eteching and diffraction effects. And multiple parallel lines have big problems with diffraction effects.
So currently it seems without a substrate then can make ...... a single p- or n- type semiconuctor material that is unsuitable for anything else.
gold is a very severe contaminant for silicon, and many other semiconductors.
It sits energy wise in the center of the band gap and kills mobility with traps.
Gold is rigorously excluded from silicon FABS, not even let in the same room.
...but if they really manage to make circuits I am really impressed.
...if you believe your new process/material can be developed to the point where it can compete with traditional silicon devices and/or processing methods you are wrong.
Only if you have an application, such as LEDs where the laws of physics say silicon can't possibly compete is there any chance you will succeed. And even then the chances are you are still wrong.
namgge
> patents have been obtained
I guess it won't revolutionize anything after all; or at least not for another 20 years.
This is very cool, but it's got a really long way to go before it can be used to build anything remotely like an integrated circuit. I'm also not sure the benefit will be that large since the wafer cost isn't a very big part of the cost of making integrated circuits today. What I think it can be great for is solar cells, nanotubes and other products where getting rid of the wafer will solve two problems: the cost and the size. If you can make an arbitrarily large solar cell panel, that's a real advantage over wafer-based manufacturing methods.
If gold were an order of magnitude cheaper than a silicon wafer Intel would be making a huge loss on their processors.
a 200mm wafer is 0.775mm thick. A quick google says this is about $1200. I'm not sure when this was, but the price keeps dropping.
If you made a 200mm x 0.775mm gold disk, it would weigh 470g. The price of gold is currently $55.40/g. That's a $26,000 hunk of metal, 20x the price of silicon wafer.
Going on the 'order of magnitude cheaper' If a 200mm wafer cost $260,000 for 31,415mm3 of surface area it would be impossible to get more than 60 xeon 8800's (513mm2) (much less, since the die in a CPU is square so the edges re unusable and there is probably a need for cutting lines, not to mention yield), The raw die alone would cost $4,333.
That seems much more feasible than what is implied by the title of this post.
This article wins today's coveted "Most Hyperbolic Headline" award. First off, here's the actual link, for those of you with access to Nature: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11652.html
To understand what the big deal is here, compare baking cookies in your house to a fancy industrial setup: In your home oven you can bake around 20 cookies at once, and you have to put them on a tray. Meanwhile, an industrial bakery has one of those fancy conveyor belt ovens -- dough goes in one side, cookies come out the other, and the conveyor belt itself is the tray. The conventional fabrication process for metallic nanostructures is more like the home method -- you need a tray (usually a silicon substrate, because those are pretty cheap and extremely high-quality), and an reactor of some sort (in this case a really fancy oven that costs more than your car, but still an oven), and you won't be getting any nanowidgets until the kitchen timer dings.
What this will NOT be useful for is logic circuitry. This group has managed to come up with a pretty good method of manufacturing metallic nanorods. That's all well and good, but bear in mind that all of these high quality nanorods are not attached to anything, and not particularly useful in and of themselves. Perhaps they can make individual nanorods into diodes, but even if they do they're still left with essentially a disordered heap of unconnected devices -- try throwing ten toothpicks in the air and having them land in a perfect grid. Now do it for a billion tiny transistors. You may notice that this process does not scale well.
This manufacturing method might actually be more useful in the realm of optics. The real breakthrough here is the fact that high quality metallic nanostructures can be grown without a substrate, and can be grown quickly and continuously. Metallic spheres and rods are actually quite interesting at the nanoscale, and behave in very counterintuitive ways (for instance, suspensions of gold spheres take on very different colors when viewed with reflected vs. transmitted light (See for instance the Lycurgus cup: http://en.wikipedia.org/wiki/Lycurgus_Cup). People are working away on using those properties to do something more useful than making a better shot glass (for instance, nanostructured metals show some promise at enhancing the efficiency of solar cells), and maybe this manufacturing method will help them out by bringing the cost of high quality research materials down.
Then again, maybe all we'll get is a few overblown press releases and another three weeks of this article on the front page at Slashdot.
Those prices are not related to the price of a silicon wafer used to manufacturing semiconductor devices. Check out http://www.gsaglobal.org/email/2010/general/0222w.htm in 2009 a 200mm wafer cost about $780. Silicon is much lighter than gold, so a wafer would be much less than 470g. Very, very far off the $22/kg for the silicon used in solar panels.
There will be at least one time that some other process came from nowhere and beat silicon litography in nealy all aspects. (The laws of physics almost assure that.)
Not so sure about that. Lithography is one of the most highly developed technologies in the history of the world, and has gone far, far deeper than most people expected as early as the 1980s. Proposal after proposal has been made to replace lithography (e.g. e-beam, MBE, etc) but all have to relegated to niche status.
Semiconductor lithography itself is highly, highly leveraged from printing processes going back hundreds of years. With this much brain power and inertia behind it I would be really, really surprised if something beats it in "nearly all aspects". Some aspects, maybe, and lithography may finally hit a show-stopper, but there won't be an "oh my, what a breakthrough" type thing to replace it. I agree it has to be replaced to maintain Moore's law, but it is already beyond comprehension advanced.
Our foundry uses 200 mm wafers. I think the cost is around $20 per wafer. I don't know, because the substrates are so cheap, they don't even charge us. Epi is a little more expensive because of the extra processing -- maybe $50.
I imagine the cost scales with wafer diameter. 200 mm is relatively old technology.