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Start the Presses: Printable Circuits Nearly Ready
akookieone writes: "MIT Tech Review has an article on Rolltronics (first appearing in /. a year ago). Seems they can now print circuits 10 micrometers across, and are thinking they could 'very shortly' move from R&D to production."
Dig deeper...
They sound robust enough for some practical applications. Remember, it's always your responsibility as the end-user to make things work. :)
From the Rolltronics website:
"Until now, the feature size of electronic components made using web processing has been in the vicinity of 50 microns and larger (1 micron = one millionth of a meter). Rolltronics is taking the feature size of its electronic components down to a much smaller dimension. "Fine-featured" as used by Rolltronics refers to component features ranging in size from approximately 0.5 to 100 microns."
printing a whole computer rather than just printing a CPU and soldering it in.
Nope, wrong application. The article says:
"these electronics are not designed for devices that require high density, like memory chips or microprocessors."
Compared to silicon chips this technology is big and slow.
The good news is that aside from computers, most uses for circutry don't require ultra-high transistor density or ultra-high processing speed.
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- - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.
I mean, they have those traces-printed-on-plastic ribbon cables connecting things like keyboards and calculator screens to components. And printer heads in inkjets.
Flex's are made using a similar process to that used to make printed circuit board. A layer of copper is stuck to a sheet of plastic and then photo etched. This is cheap but not as cheap as a normal printing process.
Plus, we have alloys which can be deposited on substrates a micron-layer at a time.
This can be done (crisp packets for example (sorry - chip packets for you yanks)) but most processes require high temperatures which don't do much good to a layer of plastic.
How tough is it to dope conducting inks with Gallium-Arsenide? (Or whatever).
Physics Today have an article about the University of Cambridge printing transistors using ink jet printers. Conducting inks are not unusual - indeed most mass produced PCBs are put together with screen printed solder paste. Its a bit of a step to call this an ink but it gives you an idea of what's possible.
Why the heck hasn't this technology been around for a decade or more? It doesn't seem so much like an advance as it does a, "They finally got off their asses and assembled the stupid thing."
The devel is in the detail. Sure I can demonstrate printing to you using some chimney soot and half a potato. Its quite a bit harder to produce a 100,000 copies of a newspaper (including those AOL CD's) for just a few pence. Development always takes many times longer than you think and far more money.
wot no sig
Look at it this way - CPUs have become much cheaper over time because manufacturing processes have been developed to reduce the size of each transistor, allowing you to fit more on a wafer of a given size, whilst increasing the size of the wafers - and the cost per wafer has not increased at the same exponential rate as the transistor count per wafer. Since it is ok that the transistors are smaller, this is a good thing. However, this model doesn't work for things where you actually want the device to be big - like a flat panel display or (as the article says) an X-Ray panel (think detector in an airport that you walk through).
What this technology does is provides a compelling economic model for large items that isn't served by conventional manufacturing processes.
One more thing - this uses amorphous silicon, also a good thing for large items in that the absence of the need for crystallinity is a big help for yield - but at the same time don't expect it to break any speed records.
Bottom line - this is a really cool technology, but it isn't going to be used for one-off roll-your-own CPUs.
Perusing Rolltronics' web site I came across this interesting nugget:
Multilevel Organic Solid State Memory
It seems you can stack up these sheets and make very dense memory out of it. Here is a quote from the article:
"They will be available in different form factors, ranging from single sheets where minimum thickness is important to stacks which can easily be put into a product that offers a terabyte of storage in a package no bigger than a pad of paper."
Appropriately enough, the author's name is Dr. Sheats.
yeah..... laserjet printable (blue) sheets for resist, $12.50 for a pack of 10 or so. ferric chloride, $5.00 for a 500mL bottle, copper clad board, $3.00 for the size I needed. Patience, priceless? (that's a total of $20.50 for you math wizzes. no where close to $100-$200) (plus, you wouldn't use an entire bottle of ferric chloride, and you only need one of the resist sheets.