Innovative nanotechnology starts to move into real product development
Anyone who’s still dismissing nanotechnology as hype had better think again. Though most actual products are admittedly still a ways off, entrepreneurs are working on applying the science to enable some potentially radical new manufacturing capabilities, ranging from higher resolution microscopes, to reusable contrast enhancement layers for printing 22 nm features with 193 nm lithography, to barrier materials that selectively deposit only on copper or only on dielectric.
These Technology Innovation Showcase (TIS) winners, developers of a half dozen of these technologies with potential impact on the semiconductor industry—selected by a volunteer committee of industry executives—will be talking about their results, and looking to engage folks in exploring potential applications, at the Emerging Technologies TechXPOT (ETX) Stage, Moscone West Hall, level 3, at SEMICON West on Tuesday and Thursday afternoons (July 11 and 13) this year. Or show visitors can stop by the winners’ booths in the Emerging Technologies TechXPOT (ETX) area in West Hall, level 3, any time during the show to learn about developments in nanotechnology.
“Some of these technologies are a little further away from full products, but we wanted to give people a chance to talk about this stuff,” says Ralph Kirk, the SEMI director of technical programs.
The ability to stack three atoms on the tip of a pin looks like it may at last enable a helium ion microscope, with resolution down to 0.25 nm, or some 5x to 10x better than existing SEMs, with high contrast between different materials, and without the need for thinning the samples as for TEMs. Alis Corporation, Peabody, Massachusetts, will be showing images from the first beta models of its tool, just turned on in May. The company plans to ship three units later this year to a university, a national lab, and a chip maker, and aims to start commercial shipments early next year.
While an electron microscope source scatters secondary electrons from the sample surface, limiting resolution to the apparent beam width of ~2 nm–3 nm, the helium ion beam’s secondary emissions tunnel into the sample, so the apparent beam width is almost as small as the incoming beam. Actual resolution will depend on engineering work still underway to limit noise and vibration.
In contrast to earlier helium source millimeter-sized beams, this one ionizes the helium at its pyramid tip of three atoms, making a sub-nanometer beam, for a virtual point source. “High-end field emission SEMs have a weakness in their ability to image with contrast—you can see a nice picture but you can’t tell one material from the next,” says Alis, VP of business development at Clarke Fenner. “So we expect fast penetration at the high end.”
A little further out in the future is the possibility of using wide bandgap nanocrystals for a reusable contrast enhancement layer—potentially allowing simpler double-exposure lithography with higher resolution and better overlay alignment. Pixelligent Technologies, College Park, Maryland, puts nanocrystals in a polymer matrix for a spin-on resist topcoat. The material is excited by 193 nm photons and lets them pass, then instantly relaxes back to an opaque state, so it enhances the pattern on the first exposure, then reverts to opaque and can be used again immediately to enhance a second exposure pattern, eliminating the need to deposit, etch, and recoat a sacrificial layer, and the need to realign the second exposure. This cuts out eight process steps and 40 percent of the cost of the typical double-exposure process, while significantly improving resolution and alignment. “We’re told by one big chip maker that the best they can get now with two exposures is +/- [plus or minus] 20 nm overlay, but this should get +/- 5 nm overlay,” says acting CEO Ken Rygler.
The company aims to license the technology for the 32 nm generation, but notes that one potential customer is interested in a 248 nm version to extend the life of older generation tools as well. Pixelligent is working now on the nano engineering issues of getting uniform particles uniformly dispersed in appropriate amounts, aiming at hard data by 3Q, alpha product samples for customer evaluation by the end of the year and a beta version shortly thereafter.
First commercial application for Cambrios’ radically new toolbox of protein templates to create designer inorganic materials will likely to be a coat-on replacement for sputtered indium tin oxide (ITO) for displays, targeted for the market in about 18 months. Cambrios is now talking to equipment suppliers and display makers about developing processes for roll-to-roll and traditional resist coaters to deposit its water-based solution on flexible substrates, where it will assemble a flexible transparent conductive film. VP of business development Hash Pakbaz says the new material is a better conductor, and more transmissive, and will likely be less costly than sputtering ITO on huge display substrates.
Cambrios is also in early development of designing a molecule with high affinity for copper, and low affinity for dielectric for depositing an electro-migration barrier selectively on the copper only. “The copper and bath materials are about the same as standardly used, but the plating is only activated by our sensitizer,” says Pakbaz. “Then, in principle, our organic material could be annealed out.” The company has also designed molecules with affinity for low-k dielectrics that allow very conformal deposition, and for plating a uniform copper seed layer on TaN. “Our goal is to attract enough attention to get people to converse with us, so we can start to work on real problems,” says Pakbaz.
Other featured nanotechnology developments include NanoDynamics’ process for atomic layer deposition of coating on ultra-fine particles in a fluidized-bed reactor, which can adjust a material’s surface properties while maintaining its usual bulk characteristics. That capability can, for example, create better thermal interface materials in packaging. The Buffalo, New York company says putting a 1 nm layer of Al2O3 on boron nitride filler particles improves their surface wetting to allow 2x–4x more of the thermally conductive filler to be added to epoxy resin encapsulant, without increasing viscosity to cause processing problems.
Other showcased new nanotechnologies from small companies are in fact already deployed in real tools in use at major chip makers. Ascend Instruments, Beaverton, Oregon has an extractor that can be controlled with nanoscale precision inside the SEM to cut TEM sample preparation time in half. Metryx, Bristol, United Kingdom shows off a tool for measuring the mass of wafers with nano-scale precision, allowing quick assessment of a wide assortment of processes, from high-k layers to MEMS etching.