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Hardware Technology

Self-Building Chips — As Easy As Microwave Meals 51

Posted by CmdrTaco
from the only-blinks-12:00 dept.
nk497 writes "Canadian researchers have found a way to speed up self-assembling chips — by using microwaves instead of traditional ovens. Self-assembly is seen as key to enabling nanotechnology, but until now the block co-polymer method, which directs nanomaterials to create moulds and then fills them in with a target material, was too slow to be useful. 'By using microwaves, we have dramatically decreased the cooking time for a specific molecular self-assembly process used to assemble block co-polymers, and have now made it a viable alternative to the conventional lithography process for use in patterning semi-conductors,' the researchers said. The technique could make the technology a viable alternative to conventional lithography for chip production. 'We've got the process — the next step is to exploit it to make something useful.'"
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Self-Building Chips — As Easy As Microwave Meals

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  • Anonymous Coward (Score:1, Informative)

    by Anonymous Coward on Tuesday October 26, 2010 @12:34PM (#34026306)

    Microwave: Grey, bland, dry, rubbery.
    Traditional: Golden brown, tastier, juicy, crisp in the outside - tender in the inside.
    There's no comparison.

  • This is Useful How? (Score:4, Informative)

    by TinyEngineer10 (1859624) on Tuesday October 26, 2010 @12:36PM (#34026340)
    This is not all that different from 'conventional lithographic techniques' from the way I understand this article (albeit which does nto include very much detail at all)

    Traditionally the photoresist which is being patterned is either having bonds broken to let exposed areas be dissolved away, or bonds made to keep the exposed areas in following steps. At the end of the day you're shining radiation on a substrate to make a pattern.

    Here is seems to me is they're using block co-polymers to assemble between different configurations - a soluble and insoluble one I imagine? At the end of the day they're still using the idea as traditional lithography. Why investigate this method when there's wavelength limitations that are currently hit I have no idea.

    Microwaves are sitting at a higher wavelength than UV/extreme UV which is in use today so I don't see this being useful for patterning for semiconductors. Perhaps if it's cheaper and more compatible I could see this put into lab-on-a-chip style fab methods or something else...
  • by pushing-robot (1037830) on Tuesday October 26, 2010 @12:53PM (#34026558)

    s/higher/longer

    And I'm no expert, but I think the microwaves are just used as a heat source to cure the material so their wavelength is immaterial. In TFA it says they're being used to replace "old-fashioned convective cookers".

  • by durrr (1316311) on Tuesday October 26, 2010 @12:57PM (#34026600)
    They are using molecular self assembly to do the chip features, the radiation wavelength is irrelevant for this process, this is quite apparent from reading the article which states they swtiched form a "convection oven", i don't see convection ovens having much wavelength so obviously it's used as a heatsource to drive the reactions, not for etching.
    Via wikipedia i found an article stating 10nm is within reach for the method.

    As to what the actual method is in details i'm not much wiser. But supposedly it's supposed to be simpler and allow smaller features than used today.
  • Self assembly? (Score:3, Informative)

    by fiannaFailMan (702447) on Tuesday October 26, 2010 @12:58PM (#34026626) Journal

    TFA doesn't have much detail, in fact it doesn't have much of anything. I've even posted it below. What I was missing was an explanation for the "self assembling" claim. I had to go to Wikipedia [wikipedia.org]. I think the article submitter could have added that as a courtesy.

    TFA:

    Researchers at Canada's National Institute for Nanotechnology (NINT) have developed a way of quicker way to enable self-assembling semiconductors - using microwaves ovens.

    The technique could make the technology a viable alternative to conventional lithography for chip production.

    Self assembly is seen as key to enabling nanotechnology, but until now the block co-polymer method, which directs nanomaterials to create moulds and then fills them in with a target material, was too slow to be useful.

    However, the Canadian researchers found that by switching from old-fashioned convective cookers to newfangled microwave ovens the process time was reduced from days to less than a minute.

    “By using microwaves, we have dramatically decreased the cooking time for a specific molecular self-assembly process used to assemble block co-polymers, and have now made it a viable alternative to the conventional lithography process for use in patterning semi-conductors,” the researchers said.

    "This is one of the first examples of the self-assembly process being used to address a real-world problem for the semi-conductor industry," said Dr Jillian Buriak, head of materials and interfacial chemistry at NINT.

    "We've got the process - the next step is to exploit it to make something useful."

  • by JustinOpinion (1246824) on Tuesday October 26, 2010 @01:33PM (#34027100)
    As another poster points out, the microwaves are being used as a heat source (not for patterning), instead of oven annealing. It turns out that a microwave can cause the material to assemble much faster than conventional oven annealing, which is pretty exciting.

    As for the "Why use self-assembly for lithography?" the basic idea is this: Conventional optical lithography is limited by the diffraction of light (as you mention). So for typical visible-light optical schemes, the best you can do is pattern features on the order of ~100 nm (using a bunch of tricks you can push a bit below this, which the semiconductor industry has done with fantastic results). In self-assembly, you design molecules that spontaneously form nanostructures of a well-defined size. So instead of enforcing a particular size-scale using light and patterning masks (top-down fabrication), you design the required size-scale into the molecules themselves (bottom-up fabrication).

    In the work described in TFA, they were using block-copolymers, which are polymers (long chain-like molecules) that are have two chemically-distinct "blocks". So one half of the chain is of one kind of material, and the other half of the chain is another type of material. Like so:
    AAAAAAAAAAAAAAAAA-BBBBBBBBBBBBBBBBBBBB

    Because the "A" and "B" subunits don't like each other (they are sufficiently chemically distinct), they want to separate from one another (like oil and water not mixing). But because they are bound to one another using a covalent bond (the "-" in my diagram), they can't fully separate, and instead form nano-structures with a size-scale dictated by the length of the A and B blocks. So you can control the size using the lengths of the blocks, control the segregation using the chemistry of the two blocks, and control the morphology [nyu.edu] (the structures that form) using the ratio of the A block length to the B block length.

    This process is fantastic at making well-defined structures at the nano-scale (down to 10 nm has been demonstrated; down to 5 nm seems do-able). However one still has to control the positioning of these structures. So a lot of work has gone into combining self-assembly with conventional photo-lithography. The conventional lithography defines the long-range registry and pattern; the self-assembly lets you fill in that pattern with ultra-small structures. In case you think this is all theoretical, Toshiba recently announced [slashdot.org] a working prototype hard-drive with magnetic dots made using these techniques.

    Disclaimer: Part of my research is in this area, so I may be biased towards thinking this is cool/novel/useful.
  • by JustinOpinion (1246824) on Tuesday October 26, 2010 @02:22PM (#34027724)

    Are these co-polymers being use as an organic electronic material say in OLEDS or are they designed so that they have a specific configuration to essentially after assembling they are in the pattern you want them to be?

    The dream is to have the block-copolymer blocks be functional. So, say one block is the donor and one the acceptor in an organic photovoltaic. Or the blocks form an OLED as you suggest. Or one block has a sensing element and the other block acts as electrode contacts. Or one block has reaction centers that can be metallized to generate wires.

    The current state of the art is more primitive, with the assembled block-copolymer being used as a resist, since the two blocks will have different etch contrast. So in the case of the Toshiba work (Hitachi is working on something similar) the block-copolymer nano-dot pattern was used as a resist to etch into a magnetic layer and thus form magnetic nano-dots with a much higher area-density than could be done with conventional optical lithography (or something similar to that: they have not released full details). We're still not at the stage where we can build something as complex as a transistor using block-copolymers as the resist(s), but we're getting there.

    are they designed so that they have a specific configuration to essentially after assembling they are in the pattern you want them to be?

    Originally the hype about self-assembly was that the molecules would spontaneously form the devices you want ("Pour the components together in a beaker and a computer pops out!"). I think the field is getting more realistic now, and accepting that self-assembly has to be coupled with other techniques (such as optical lithography to control the larger-scale positioning, or annealing tricks, as in TFA, to direct the assembly) to create fully-functional devices. But self-assembly can still provide a level of nano-control and cost savings compared to more laborious techniques.

  • by JustinOpinion (1246824) on Tuesday October 26, 2010 @02:42PM (#34027976)
    For those with journal access (American Chemical Society), here is the actual scientific paper:
    Fast Assembly of Ordered Block Copolymer Nanostructures through Microwave Annealing [acs.org] Xiaojiang Zhang, Kenneth D. Harris, Nathanael L. Y. Wu, Jeffrey N. Murphy, and Jillian M. Buriak, ACS Nano, Article ASAP DOI: 10.1021/nn102387c [doi.org].

    Here is the abstract:

    Block copolymer self-assembly is an innovative technology capable of patterning technologically relevant substrates with nanoscale precision for a range of applications from integrated circuit fabrication to tissue interfacing, for example. In this article, we demonstrate a microwave-based method of rapidly inducing order in block copolymer structures. The technique involves the usage of a commercial microwave reactor to anneal block copolymer films in the presence of appropriate solvents, and we explore the effect of various parameters over the polymer assembly speed and defect density. The approach is applied to the commonly used poly(styrene)-b-poly(methyl methacrylate) (PS-b-PMMA) and poly(styrene)-b-poly(2-vinylpyridine) (PS-b-P2VP) families of block copolymers, and it is found that the substrate resistivity, solvent environment, and anneal temperature all critically influence the self-assembly process. For selected systems, highly ordered patterns were achieved in less than 3 min. In addition, we establish the compatibility of the technique with directed assembly by graphoepitaxy.

  • by westcoaster004 (893514) on Wednesday October 27, 2010 @04:48PM (#34042358)
    The structures made by block copolymers can be either functional (or a template to make something functional) or used as a mask (like a photoresist) for chemical etching (so it is, in a way, a replacement for a photoresist). In one of the examples from this paper, the block copolymers are used to template the formation platinum nanowires; these could be used either as a functional structure or as a mask allowing one to etch a very fine striped pattern into the surface. The unique feature of using microwaves is that it speeds up the self-organization of the block copolymer, allowing it to realize a minimum energy configuration (i.e. the desired pattern); other methods have generally required a substantial period of time to fully organize. This method manages to complete the organization in under 4 minutes, which is something that the ITRS (published by the Semiconductor Industry Association, see: http://www.itrs.net/ [itrs.net] ) has stated is a necessary step for the commercial implementation of block copolymer lithography. The paper, published in ACS Nano, really goes into details. If you /you institution is not a subscriber, you can still access the Supporting Information free of charge [acs.org] which includes dozens of pictures & SEM images and a video.

    (rohtua ht4 eht m'i)
    (oops... didn't mean to do that last one anon.)

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