Chipmakers, struggling with soaring lithography costs, are making a concerted effort to push current tools as far as possible. Most fabs today use 248 nanometer lithography to etch .13 micron parts, and will use 193 nanometer lithography systems to create 90 nanometer and 65 nanometer ICs. Research into immersion lithography has been so successful that some chipmakers now believe that ASML, Applied Materials, and Nikon, are becoming increasingly confident that conventional 248 nm and 193 nm tools, enhanced by immersion lithography, will obviate the need for next-generation lithography technologies. Immersion-enhanced 193 nm lithography can etch 20 nanometer transistors, theoretically allowing next-generation fabs to dispense with Extreme Ultraviolet Lithography entirely. If EUV is perfected, however, it will be a technically superior (albeit far more expensive) solution to immersion-enhanced optical lithography, and may allow for “true” 20 nanometer chips. With immersion lithography chipmakers may only etch the most critical layers of an IC at a reduced size, and sculpt the other layers using courser lithographic techniques. EUV, by contrast, will allow all layers of a chip to be fabricated at the smallest dimensions.
USER COMMENTS 18 comment(s)
|First Post. (12:59pm EST Mon Mar 01 2004)
I wonder if chip structural packaging will have be changed to prevent even the slightest pressure or vibrations on such ultrafine circuitry.
– by Eleven Fingered Boy!
|Big Deal (1:35pm EST Mon Mar 01 2004)
If we still listened to vinyl records and have just discovered the antibiotics, and would not have TV and would not have crime and drugs, would we be worse off? Screw 20 nm. The pre-transistor era was better. You f–k with silicon and end up living in a world of silicone babes. F–k Ge, f–k Si. Hello horseless carriage. At least people had some fun making their own radios, from the scratch, and women were women and not feminist biches. – by Bill Ga TS
|There are SO many gotcha's… (2:35pm EST Mon Mar 01 2004)
I admit this – I was wrong a few years back thinking that physics itself limits focussing a “dot” (the fundamental unit of any photolithographic process) any smaller than a half-wavelength of the light being used in the process.
Physics DOES limit the fuzziness of a focussed 'dot' to 1/2 lambda (wavelength), but not with sharp walls. The dot turns out to have a gaussian intensity profile (bell shaped), with light falling outside the half-wave radius, and most (“one sigma's worth”) being inside that magical radius.
But… it is through the combined magic of 'stochiometric' exposure, and multi-exposure phased indexing (whereby a pair of maskings create a smaller line than either is able to do on its own, by shifting them a handful of nanometers with respect to each other) that the finer line widths are being made. The resists have been developed to have highly nonlinear exposure/polymerization curves, which in turn allows sub-critical exposures to open less than 1/2 wavelength of channel.
All good. But also very restrictive. Since the sub-wave features have to be made from both overlapping phase-shift masks and critical-subexposures (and since as exposure time goes down the “Schott noise” effect begins to roughen the edges of the exposed portion of the resists), the reliability (geometric reproduceability) of the structures gets less and less certain. Translation: more noise/process oriented chip errors.
So, the subwave stuff, using some combination of immersion litho, fancy photoresists and carefully conserved design rules, works, but is also not as appealing as “direct litho”.
And, if Intel has learned nothing else over the decades, is that they need to make money by having brilliantly reliable chip-manufacturing lines that can keep on chugging, month-in and month-out. Hence why they really want a 'chipscale' 30 nanometer EUV technology. We can be sure that they've actually envisioned uses for that wild'n'crazy tech when it comes online.
Yes, it was more 'pastoral' to have lived in an era where one went to the drug-store/fountain for a soda and ice cream, where at the little ol' german fellow's 5-and-dime, one could purchase the most primative tubes, sockets and ridiculous oversized resistors (and does anyone really remember the 90 volt “B” battery?) and build a radio.
But we no longer think twice about how the “touch tone” telephone works (you wouldn't believe how many articles were published about the “DTMF encoder/decoder”), or how that GPS thingy that is becoming ever-so-ubiquitous in Chrystler vehicles works. I bought the lil'geek in the family some 7400s, LEDs, and a nice little plugboard. He's not interested. It ain't a computer game. Maybe at 13 y.o., its too soon … but I fear that the next generation is going to be suspiciously short of the creative genius that has to be rooted in “basics” in order to give us all the cool stuff that we now have.
It is for that reason that I guard against Ludditeism.
– by GoatGuy
|You're Forgetting (3:31pm EST Mon Mar 01 2004)
You're forgetting about the indeterminant phase-variance of the refracted photon stream through the abjective aperture being limited on both sides by the uncertainty of photonic polarization (i.e., Heisenberg). When the photon stream transitions through multiple carrier mediums, the inverse transitive refractional properties undergo a decrease in probablity by the cube of the mediums permittivity, thus the phase-variance quickly goes assymptotic and we loose control of the photon stream with out an incredibly precise phase discriminator.
This should be third grade quantum physics, man. – by Dude
|Photon STREAM? (6:55pm EST Mon Mar 01 2004)
OK – I read it 3 times. Twice, I fell off the floor laughing. The first time was dicey though. Had me going.
“Indeterminant phase variance” … more or less referring to per-photon phase incoherence. OK so far.
“refracted photon stream” … i.e. the focussed imaged. Still OK.
“abjective aperature” … let's assume you really meant “objective lens system”, … and we're still OK.
“being limited on both sides” … for straight lines? OK, if that's what you're talking about.
“limited by uncertainty of photonic polarization” … hmmm, now the continuum is starting to break. I think you're trying to say that there's gonna be wicked noise on the gaussian slopes unless high photon fluxes and long exposures are used to smooth things out … [OK still]
“(i.e. Heisenberg)” – Sorry, but our Favorite Father of the Metaphysical don't really figure into it. Straight statistics of randomly oriented waves works nicely. … but lets move past this.
“photon stream transitions thru multiple carrier mediums” … like, through all that glass, hyperpure water, air, vacuum and all the cements holding the stuff together? OK, I'll buy that
“inverse transitive refractional properties” … throw out “inverse and transitive”, and it might still make sense.
“undergo a decrease in probability by the cube of the mediums' permitivity” … no, I think not. In any case, permitivity is related to magnetism and (anti-)/ferrimagnatism. Optically active compounds only rarely are also ferrimagnetic. So, now I've lost your thread.
“Thus phase variance quickly goes asymptotic” … ummm, this is confounded by the [lack of] permitivity aspect, and secondly, anything that goes “asymptotic” needs to 'asymptote' TO some condition. If you mean that a coherent, phase locked photon flux will decohere by going thru all them million buck lenses, well, they don't, and moreover, the industry doesn't like coherent light sources.
“we loose control of the photon stream without an incredibly precise discriminator”… ROFLMAO
Thanks for the pull thru the weeds, Dude. Any time, any time.
– by GoatGuy
|Dude (7:07pm EST Mon Mar 01 2004)
I happen to agree with Dude. – by Time
|Hmmm.. (12:48am EST Tue Mar 02 2004)
I agree that with all the bells and whistles, optical lithography appears to be on life support. But actually EUV is more restrictive, and optical is still the smoothest way to go. There is general agreement from EUV supporters anyway that EUV has a long way to go.
EUV requires probably one or two orders of magnitude more power than current levels. Since EUV photons are more energetic than DUV photons you need more intensity to keep the same low level of shot noise.
EUV also requires a vacuum, which is difficult to interface with the coat/develop modules at atmosphere.
It is a terrible thing to use EUV for less critical features, because that wastes the money spent on earlier litho tools, raising the overall cost of ownership. At the same time, EUV requires tighter and tighter mask CD control for the critical features as dimensions get smaller. (Currently, we hope phase-shifting to bring some relief from this trend.)
Perpetually shrinking the wavelength is the old-style thinking, believe it or not. You have to think optimum technology. Until optical runs out of steam, it will be optical. – by litho expert
|what about self-assembly? (1:33am EST Tue Mar 02 2004)
Maybe that will be the new paradigm after lithography? – by go molecular
|Re: go molecular (1:39am EST Tue Mar 02 2004)
Yes, it's certainly possible, and I'd suggest to define the boundary conditions of self-assembly with lithography. – by litho expert
|WELL (2:13am EST Tue Mar 02 2004)
I agree with the very first post, or more exactly the last sentence of the first post.
We live in a nation of Bull Dikes – by 3141889
|Goatguy (8:44am EST Tue Mar 02 2004)
Don't you ever watch Star Trek, it is all explained there.
I'd hoped that you'd get a laugh out of that, it was only intended as a joke. I took some of my undergraduate physics and years of watching Geordi LaForge and Lt Cmdr Data spout techno-babble on Star Trek and wrote you a nonsense reply.
– by Dude
|Dude – (10:18am EST Tue Mar 02 2004)
That's what I was saying! The joke was on me, really, in that I took what you were saying seriously… until I got to the end, and by that time I was ROFL.
No, haven't watched any of the “new generation” Trek. 'Fraid most of my 'trek days' were back in the late 1960's and early 1970's. Not so much technobabble, 'cuz there wasn't so much 'tech' in the world. Mostly evil Klingons, pissed up Trilithium crystals, peoples brains swapped into lava lamps, blown warp drives, strange energy clouds, planet-eating, black spray painted “bugles” shot in macro and if you looked carefully, a whole lot of nailheads showing in plywood “sets” visible cuz it was “the '60's man”.
But my bro' and I loved it. What can I say. Once a geek, always a geek.
– by GoatGuy
|I was Mad (1:29am EST Wed Mar 03 2004)
I was like, “holy christ, I have no Idea what this guy is talking about.”
Typically I follow pretty well and I know enough to know that there is a lot of stuff I don't know. But my bulshyte-o-meter was pegged and I just do not have a skill set that would allow me to analytically refute anything Dude said.
I am so happy it was bull, otherwise I would have spent hours researching to see if I could find a squeegy for that steamer.
– by Perdo
|Need a million of these… (3:34pm EST Wed Mar 03 2004)
I remember GoatGuy's old suggestion of arrayed columns. A 1000 X 1000 array seems to be what is needed. – by go maskless
|RE: maskless (10:48pm EST Wed Mar 03 2004)
High throughput means no vacuum. You are better off using high-throughput ebeam for making the masks for contact printing lithography.
Of course, you'd have to ensure these masks are ultraflat. And make sure there are no defects. The interest in nanoimprint presumes that these issues are already resolved. – by litho expert
|link changed (10:53pm EST Wed Mar 03 2004)
or just search “10 nm resolution ZrO”
Just sharing the current resolution capability and a suggestion of improving ebeam lithography throughput.
But you are right about the vacuum. Bummer. – by go maskless
|NGL exposure basics (8:39pm EST Wed May 11 2005)
EUV (like the other NGL techniques)generates secondary electrons. It is the secondary electrons which break the resist bonds to allow finer lines to be etched. EUV photons are not the primary agents responsible for the final image.
Even if the EUV light is focused to the tightest dimension, the EUV-generated secondary electrons diffuse a much greater distance (tens of nanometers). These will actually result in blurring of the image, making it impossible to control reliably.
So it is not surprising at all to find immersion lithography being called in to fill in for NGL's original purpose. – by someone in the know
|Re: secondary electrons (7:23pm EST Sat Aug 27 2005)
Nanoimprint and DUV both avoid secondary electrons, so it seems after immersion, nanoimprint will take over. To make the nanoimprint template you would still have to use DUV. Work on further developing optical maskless technology has already started . – by someone in the know