In two related articles from www.physnews.com they seem to claim completely
One is here "Intel Begins $2 Billion Conversion Of Arizona Factory to Start
65 nm" http://www.physorg.com/news52.htm
And another "Scaling dead at 130-nm, says IBM technologist"
I'm really confused!!! One say we will never go over 90nm, and at the same
time Intel spends a lot of money to build a factory for 65nm!
I think that the point is that simple scaling - "die shrinks" - are no
longer feasible, as they were in the past. Time was, when you got
better process resolution, you could just crank the optics to reduce
an existing mask set. The physics has changed nonlinearly, so new
device designs are needed to exploit sub-100 nm features. Several
people have 90 nm stuff in production, but it ain't easy. At 50 nm and
down, whole new devices, finfets or something, will be needed.
Not to mention that smaller feature size is not the major driver of
so-called "Moore's Law". Crystal defect density has been the major
driver in recent years. Moore's Law says the number of transistors
per device doubles every two years. Scaling down the linear dimension
by 2 increases the transistor density by 4, but that's hard to do.
Decreasing the defect density allows you to build larger chips
that can be manufactured with acceptable yield. Feature size
may hit a law-of-physics stumbling block, but that will not happen
to advances in reducing defect density. Until we have single chips
the size of dinner plates, there will be room for improvement based
on defect density alone, which is the major driver for Moore's Law.
Good point. It's easier to cool a bigger chip, too.
Of course the other problem is: how much engineering does it take to
design a working billion-gate chip, and then who wants it?
Electronics is just about 100 years old, approaching a mature
Nothing grows exponentially forever. The problem in today's
electronics industry is increasingly the difficulty of finding a
"killer ap" to absorb the incredible amount of compute and storage
capacity now available. Most people haven't bothered to install 2G of
ram in their PCs, even though it's now cheaper than 64K was a decade
or so ago. My 700 MHz Dell has 128M of ram, and works fine, even for
circuit simulation and CAD use.
Huge-capacity nanotech data storage (if it ever works) may just be in
time for the tail end of a boom, when nobody has a really good use for
it. Storing lots of violent movies might be cool, but is hardly any
sort of boon to humanity.
You're right about the movies. But if you try to install and run some 3D
software or just some graphic tools commonly used on the market, you'll see
the reason of installing some extra RAM etc.
Also I bet new Windows would kill your mashine even if "system requirements"
would let you run the installation at all. Ordinary word processing software
shouldn't take this much of your CPU, right? Try to find the version of MS
word that could be launched from your old trusty 386 machine. Were those
version bad? Raising our hardware requirements is part of the game. The days
when guys cared for memory used by the codes they developed are all gone.
napisa w wiadomoci wrote:
Various sources cite 1 year, 18 months or two years, and target number of
devices, "complexity", power consumption and reliability as the factors and
Moore's paper appeared in 1965, when he was with Fairchild Electronics, in
Electronics Magazine, when that was still a meaningful publication.
Right, I agree that Moore's Law can be driven by other factors than scaling.
But then I don't understand what they mean saying "65 nm technology
(process)", or even "45 nm", look here http://www.physorg.com/news74.html -
"East Fishkill, N.Y. and Seoul, Korea - March 5, 2004 - Samsung Electronics
joins a strategic semiconductor technology development partnership with IBM,
Chartered Semiconductor Manufacturing and Infineon. Initially, the four
companies will focus on 65 nanometer (nm) technology and will expand, over
time, to include 45 nm process development."
Do they mean something like "equivalent device size"? Like for gate
dielectric thicknesses. Or 45 nm is a real FET size?
These numbers are characteristic dimensions of features (DRAM half-pitch,
etc.). Essentially, you can think of these numbers as the gate width.
There does not seem to be any reason not to be able to make things this
small. The big problem is the on-chip wiring. About now, there is about 9
layers of thin, skinny copper wiring on top-of-the-line chips (I say
top-of-the-line in terms of manufacturing acheivement, not performance).
At some point, you would be making tiny transistors buzzing away like crazy
that are farther apart from each other than was the case in the previous
generation, because the wiring would limit the performance too much if they
were spaced closer together. The cost advantage of puting more transistors
per unit area would disappear, and the cost would go up fast.
This is why people are looking at 3D ICs and such: interconnection.
---> Insert shameless plug for the article I wrote in the March 2004 issue
of IEEE Spectrum. The money keepers need to understand this stuff before the
engineers have a chance to do what they need to do. <---
Thank you for that answer.
I do agree with you about interconnection problem.
But it also sounds from your post like this interconnection problem is
the only problem that exists and as you write, "there does not seem to
be any reason not to be able to make things this small".
I cannot agree on that.
I've intentionally looked to International Technology Roadmap for
Semiconductors web-site http://public.itrs.net /
They have a list of Grand Challenges for the near (< 07) and
long-term (beyond 2008)
On the first place they set low gate leakage current saying that
high-k must already be implemented in 2005 (to me they already are,
look for instance here http://www.physorg.com/news80.html )
Then they say about large area substrates (300 mm).
Then there are several problems with lithography listed, as
mask-making and process control.
And finally we come to interconnect, which is also a great challenge.
See the whole list of challenges here
Long before we reach that point, we will probably be forced to transition
from dissipative logic to reversible logic. (The only computing operations
that _have_ to generate heat are I/O operations.)
Nanotech will probably also require reversible logic, in order to avoid
For links to reversible computing and its relation to nanotechnology,
see <http://www.zyvex.com/nanotech/reversible.html .
For one group that has performed some excellent experimental research into
reversible computing, including building some prototype devices, see:
-- Gordon D. Pusch
perl -e '$_ = "gdpusch\@NO.xnet.SPAM.com\n"; s/NO\.//; s/SPAM\.//; print;'
Yeah, I know--I work in the building where reversible computing was invented,
many moons ago. If CMOS is really running into a brick wall, though,
there'll be enough blood on the landscape that we may all be out of work
before reversible computing becomes practical (if that ever happens).
There's a _lot_ of work going on just now on how to cool next-generation CMOS
without circulating water right to the chip level. People are even talking
about cutting channels into the back surface of the chips, to run cooling
water. I don't think things are quite that desperate, but we're clearly in a
On 8 May 2004 03:21:19 GMT, g_d_pusch_remove email@example.com
(Gordon D. Pusch) wrote:
(I posted this earlier on comp.arch, but perhaps someone here may know
On thermodynamic grounds it's expected that reversible computing could
reduce heat dissipation - very relevant today since heat dissipation
is becoming an important limiting factor on the performance of
At first glance, though, it would seem that running most algorithms on
a reversible computer would just replace the consumption of power to
erase N words of memory, with the consumption of N words of memory -
which means you quickly end up running out of memory and have to
switch to irreversible mode and erase used memory cells after all, so
But on http://www.kuro5hin.org/story/2003/9/8/14125/70302 I found the
"The actual limitations of reversible computing are small:
The number of bits input to the computation must be the same as the
number of bits that the computation outputs. Call this N.
The number of bits that a reversible computation needs to remember at
any point is also N.
Given a irreversible computation with Ni input bits and No output
bits, it is possible to produce a reversible computation with N not
greater than Ni + No."
Does anyone know of any examples of how this might be done with
practical algorithms? (Google shows me lots of articles on how to
reversibly do the equivalent of NAND, but I'm interested in how to
reversibly do things like sorting, matrix multiplication or alpha-beta
"Sore wa himitsu desu."
To reply by email, remove
Close. The connections will be compliant, as in packages
pioneered by Tessera (http://www.tessera.com ).
To connect to a whole wafer, you might use spring-based
probes, like FormFactor does (http://www.formfactor.com ).
Of course, why a wafer the size of a dinner plate need to
have any large number of connections? If it has a video
output, stereo output, couple of USB plugs, and a few
other things, that can be done in a small number of pins.
You could put them in the center, like is done now for
flip-chip, to minimize solder ball stress caused by temperature
cycling and CTE mismatch. By then, of course, we won't
be using lead-based solder anymore. Raising this issue
is like proving airplanes are impossible because physical
laws dictate a minimum power-to-weight ratio for steam
[ Sci.nanotech moderator's note: The relevance of this thread to
nanotechnology, while initially thin, appears to have run its course so I
am setting the "Followup-to" to exclude sci.nanotech. Posters are welcome to
re-include sci.nanotech if they think their response is topical here.
Now on with Phil Hobbs interesting reply.... -JimL ]
Mark Thorson wrote:
We obviously don't live in the same world. People where I work actually have
to do this stuff for real, and it isn't anything like as simple as you make
out. Even with perfectly matched CTEs, just the *gradients* due to a
100W/cm**2 power dissipation level make everything want to roll up into a
ball. Talking as though the interconnect were just a matter of plugging a
keyboard and USB cable into a wafer-scale device shows very little
understanding of the problems of the day.
Interconnect densities are currently above 3000 leads per module, and heading
up--one high performance design study I'm aware of needs over 7000, just to
get all the terabits-per-second off the module. (Current products are around
1 Tb/s total off-board I/O for a board with one module on it, and it's going
to go much higher.) Just powering the thing takes 100 amps per square
centimetre of chip surface, from a 1-V power supply, whose total impedance
has to be well below *1 milliohm* at all frequencies of interest. Power,
ground, and bypass caps have to be sprinkled *very* uniformly across the face
of the chip, just to avoid logic errors due to power and ground bounce.
Spring clips and so on lead to scrubbing action at connector surfaces, which
is a reliability headache. You can't simply suspend a dinner-plate-sized
module on legs near the centre, because it won't stand shock testing, and has
to hold up a big copper plate heat sink. And so on and so on.
These things can be overcome--comparable ones in the past were--but in real
engineering, it has to be cheap and reliable as well as everything else.
Huge chips are probably not the most cost-effective solution.
Advanced Optical Interconnect
IBM T.J. Watson Research Center
Yorktown Heights NY
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