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Diagonal Design For Chips
A reader writes "Simplex and Toshiba have a new design tool that allows circuits to run on diagonals. They're calling it X Architecture. Applied Materials, KLA-Tencor and DuPont Photomasks have signed on according to the press release. They're claiming 20% less 'wire', 10% faster, 20% less power and 30% better yields. Here's an EET article."
Perhaps it's just me, but I'm not all that excited about this. One of the key things to highlight is that this is just a tool and a method for doing 45 degree angles on chips.
The word in the above statement is IF. That's a big if. Just because you can design something doesn't mean that you can fabricate it.
As an interesting little side now, it should be noted that some of the people working on good old Magic are trying to implement non-manhattan geometries in it also. Although, doing it on a router would be kinda tricky.
My Slashdot account is old enough to drink...
Hasn't this already been used for a while in several fab houses?
When I went through Comp. Eng. undergrad, I was told that there were two layout styles used in industry. "Manhattan rules", which forced all edges in the layout to be horizontal or vertical, and "Brooklyn rules", which let you use diagonal edges as well.
The high-level synthesis tools won't care - they're just manipulating gates from the cell libraries, and letting the place-and-route tool worry about layout.
The place-and-route tool would have to be tweaked to allow diagonal lines, which would be a substantial undertaking, but hardly earth-shattering.
The cell libraries would have to have modules implemented that took advantage of the layout rules, but you have to make new cell libraries for every new process anyways.
The lithography process itself doesn't care what design rules you use. It just forms images that have a certain minimum feature size and certain mask positioning tolerances.
If Brooklyn rules really are used in industry, then these tools already exist.
I'm just trying to figure out what's "news" here. (Maybe mixing the two rules methods, which is a fairly neat trick to help those stuck with Manhattan libraries.)
Since the architecture isn't going to change on the top layers, where most of the action is, the improvements become incremental. It would be nice, though, to be able to shorten long interconnect runs, especially with capacitance becoming a significant issue now. But I wonder if the significant cost to replace existing design and manufacturing tools is worth the seemingly small gains that the technology offers.
-h-
The problem I see with using fibre for chip-interconnect is that you need circuitry to change electrons to photons and vice-versa, which would add to the die-size significantly. You'd also introduce a delay while the photon/electron conversion happened. At the trace lengths that are on today's chips, that delay would likely negate any advantage in speed. There would be gains in electical isolation (interconect crosstalk), however.
BTW, fibre carries a lot more data because it can use different frequencies (multimode fibre) and doesn't suffer electrical attenuation at higher frequencies. I don't think you'd be able to use multi-mode fibre on a chip without needing serious power and realestate. The only place I could see an advantage to fibre in a chip would be to interconnect a CPU to a large, full speed off-die L1 cache. But, IANACS (I Am Not A Computer Scientist).
"Depression is merely anger without enthusiasm." - Anonymous
...and both to be hit with a suit from X.Org.
Another LHA (Lame Humour Attempt) brought to you by the letter X.
"Depression is merely anger without enthusiasm." - Anonymous
How would you have designed your eyeballs so they
...
wouldn't have been so lousy?
Did you know, perhaps, that the shape and internal
structures of said cells may help to eliminate
internally reflected, and therefore from a non-
predictable source, light? Similar to an MRI,
you might say.
There even appears to be a creationist
web-page arguing for the design of our eyes
http://www.trueorigin.org/retina.htm
They assuredly have some facts in there.
As my father lik@(munch munch)...
To Simplex, that means shorter wires. By its own estimates, wire length is reduced by 20 percent on average using diagonal interconnects. The result is a 10 percent jump in chip performance, 20 percent reduction in power consumption and 30 percent more chips per wafer, due to the smaller size, according to the company.
I wonder if anyone has looked into using fiber wires instead of copper in a PC. We all know fiber carries more data over networking lines, but I wonder how it would carry on sending light strands of electrical currency from chips to wherever.
I'm sure someone has probably attempted this, but to date I've seen nothing on it, maybe someone would care to share a link or something.
Want Root?
Actually this technology offers all sorts of advantages. In the realm of heating, since there will be less interconnects, that means less resistance, which in turn means less heat being generated. The number of transistors will still be limited by the process that they are developed in. Only the congestion of the interconnects will be lowered.
The REAL issue here is whether or not this will make microchips attractive any more. The main reason I support the use of microchips (over, say, vacuum tubes) is that they look real pretty when you blow up their pictures into poster size. The reason they're pretty, tho, is because there aren't any diagonal lines. Will chip designers keep aesthetics in mind with this new drawing tool at their fingertips? I think not. Support right angles! Support attractive computer chips!
Isn't it significantly harder to catch issues like crosstalk between wires when you can run in 4 different directions? In my experience, the biggest issues in semiconductor design are finding tools that detect and solve the design problems, not actually using the new fabrication technologies.
What I am skeptical about is that it means a whole new routing infrastructure - not just new routing tools (which I guess is what they are really selling) but also 3d extraction tools, timing infrastructure, DRC etc etc getting all of this working from all the different vendors and getting it to work together is NOT going to be easy
Curious... I figured that IBM would be the one to finally get this kind of thing out the door. That said, they forgot to mention that two 45 degree angles creates less resistance to your confused electron than a single 90 degree angle -- shorter distance too which is a bonus :)
Rod Taylor
I'm surprised it took this long for someone to get this done. I remember designers where I worked spending long hours trying to reroute cells to reduce parasitics on long wires.
But no, all they did was decide that instead of the time-tested grid format, we'll just run our interconnection wires 45 degrees diagonally accross the chip, but still pretend there are grid "nodes" for automation purposes. (for those not in the know, interconnect are the higher-level wiring that connects "blocks" of circuits together, such as connecting adders to multiplexers)
Building 3D layered chips is a whole 'nother beast.
Just remember, they're only saving wiring only at corner-type junctions, and even then, only what can be optimized to fit within the existing wiring mesh. Still, saving wiring is a big improvement; as we should all know, excess wiring causes heat, voltage, and frequency problems (due to line charging effects). On the other hand, most modern toolkits are written to optimize to a 2-D grid, not to mention most modern lithograph manufacturing tools. But, thats the point of the "discovery".
-- Scott
... who should be working
Sure, it's obvious that connecting on the diagonal will save you distance. Duh. However, no one has managed to do it reliably and successfully until now. So, clearly, there's more going on here than 'basic geometry'. The article doesn't go into any real detail about what the challenges were and how they were overcome, unfortunately, so those of us who know nothing about chip design will have to wait for more info. --S
Forgive me for being an ignorant putz, but isn't the diagonal merely a perspective issue? I know I've seen cards with diagonals...this design doesn't carry over into IC's?
A graphic, someone, PLEASE!
What'dya mean there's no BLINK tag!?
--
Escher was the first MC and Giger invented the HR department.
In short - no. Heat dissipation in wires is caused by internal resistance. Resistance in wires increases as length increases. If diagonal wires are used, wires can be of shorter length. This probably accounts for the 20% saving in power consumption.
"The universe seems neither benign nor hostile, merely indifferent." --Carl Sagan
If you decided to read the article, you might have noticed that the example processes used 5 layers of metal. The first 3 were primarily orthogonal, so they would remain compatible with existing designs. The top two layers could be used for the diagonal interconnects.
The breakthrough here isn't the physical ability to route diagonally, it's the algorithms used to handle routing diagonally (not an easy task).
Probable impossibilities are to be preferred to improbable possibilities.
Aristotele
Although there are many technical hurdles, the amount of wire in a 3D arrangement would be even less. Add high temp superconductors and we can sustain Moore's law for another 20 years.
I doubt it. "The result is a...20 percent reduction in power consumption," according to the article. Less power means less heat.
A perfectly obvious way to shorten wire lengths using basic geometry, resuling in a mere 10% improvement in performance, qualifies as "a semiconductor breakthrough as significant as copper interconnects"?
According to Moore's Law, I could have gotten the same improvement simply by postponing my purchase for two months.
-- Sig (120 chars) --
Your friendly neighborhood mIRC scripter.
* Q
P.S. If you don't get this note, let me know and I'll write you another.
yeah, it makes sense if you don't think about it. the actual cells of the eye are evolved to try to cope with the way that nerves lead out of the eye. to argue that these adaptations are a good reason for the way the nerves are is simply irrational; it's putting the cart before the horse.
:).. rofl..
I'm by far not a creationist (I am an atheist!, but that is just so I can be an ist of some kind).. darwin all the way and stuff.. but when I read this the first thing I thought was that it sounds like some kind of hack from god's nerve department.. like they found a bug in using the nerves turned the correct direction, and when playing around found that bug was less common when turned backwards, so in order to make the shipping deadline (7 days to ship isn't much time!) they turned the nerves around and released.. for better or worse..
I thought someone said there was going to be free beer!
It seems remarkable to me that just because people
cannot fathom the reason why something is designed
in a counterintuitive fashion it means that either
a god did it for some inscrutable reason or because
it's inherently wrong.
Steady there big guy.. I was doing this thing called 'making a joke'.. I wasn't questioning if there was a god (I don't believe in god) or if he was right or wrong (if I did believe in god I would probably have an opinion on this.. but atm since I don't believe in him, no opinion).. I have no opinion about the whole silly nerve ending's direction thing.. it matters not to me.. I just thought it was funny sounding.. like you know.. something a wisen old hacker would do in order to get a product out the door, regardless if there is rhyme or reason to it.. *shrug*.. see.. joke.. funny..laugh.. not serious.. got it?
I thought someone said there was going to be free beer!
My understanding is that modern processors use diamond to conduct heat outside the processor core : did they also create an orthogonal diamond layer to conduct the heat out ?
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
There, was that so hard?
"And like that
"If you think about how God would design a chip, obviously God would use 45 angles..."
If God built them they'd have brains you putz.....
DocWatson
MessEdUp
#/var/www/v