Nano Development Toolkit Additions
Paula Doe, SEMI, San Jose -- Semiconductor International, 6/15/2007
A handful of small companies have some innovative new approaches to aid the development of nanoscale processes. Karma Technologies Inc. (Los Angeles) is offering a quick-change probe-tip module that reduces atomic force microscopy (AFM) downtime. Energetiq Technology (Woburn, Mass.) is developing stable, short-wavelength light sources that do not use electrodes, so they do not degrade so fast, opening new options not only for extreme ultraviolet (EUV) process development, but also for new applications such as cleaning critical layers. Nano Cluster Devices (Christchurch, New Zealand) is selectively depositing copper interconnects only in trench patterns, potentially cutting the need for chemical mechanical planarization (CMP). “We were looking for novel technology that’s going to make a difference — revolutionary, not evolutionary technologies the world should know about,” said Skip Rung, president and executive director of the Oregon Nanoscience and Microtechnologies Institute , and a member of the Technology Innovation Showcase selection committee.
Quick-change AFM tips reduce downtime
Karma Technology is readying its production model of a modular probe microscope with a probe module that can be removed and replaced for quick change of the probe tip with minimal tool downtime. The relatively low-cost miniaturized modules include the laser and detector, so the optics can be realigned and the new tips verified and characterized all in an offline station in advance — multiple units can be kept at hand, ready to plug into the AFM as needed. The offline and repetitive system would lend itself easily to automation, said company president and founder David Ray, although the company has not yet done so. And although the module doesn’t work with other brands of AFM, “We’d certainly entertain that possibility,” Ray said.
The two-year-old company has sold one prototype, and is wrapping up design on a production system expected to be available this summer. Karma is self-funded, employing six people in the United States, with some software development done in India. Initial interest has been from companies doing optical inspection of MEMS or silicon devices in production that are interested in combining the AFM capability with a confocal microscope so that they can zero in on the area of interest visually and then bring the sample over to the probe system for a closer look.
Probe tips typically pick up debris and wear out as often as every 30-60 min in the production environment, and may take several minutes or more to change, realign, verify and characterize manually.
Stable, short wavelength light sources enable cleaning and imaging
Now that Energetiq Technology’s EUV light sources have been shining away on research systems studying resist outgassing and other aspects of the EUV infrastructure for ~18 months, the company is readying other stable, short-wavelength light sources for other applications, such as advanced resist processing or cleaning critical layers.
Like the EUV source, Energetiq’s new high-intensity 10 kW Saturn deep ultraviolet (DUV) lamp also uses induction and eliminates any electrodes to create a stable high-power flood illumination. Pulsed magnetic fields in surrounding rings induce current in the Xe/Hg plasma loop within the doughnut-shaped bulb, producing irradiance of 500 mW/cm2 across the wafer plane. The company aims to replace microwave-driven DUV lamps for removal of organics from both wafers and displays, claiming lower consumables cost, lower temperatures, and wider illumination field, particularly targeting applications that need higher power or higher throughput. It also helps that the Saturn lamp has its bulb, power supply and water-cooling system fully integrated into a single compact package that can mount on a typical cluster tool.
Industry veteran Don Smith’s latest company produces its EUV light with the usual Z-pinch technology, but induces the current into the discharge plasma instead of using electrodes, which eliminates the metal debris produced as they degrade. It also magnetically confines the Z-pinch plasma in the center of the source away from the sides, which allows for the use of a long-lasting ceramic for the central bore. The result is a very stable light, with 4-5 µm positional stability. The central bore can last 6-12 months before needing changing on the 10 tools now running in labs around the industry. The system creates 10 W of EUV light at the collector.
With these products out in the market, Energetiq is looking for new light source challenges. “We’re looking for OEMs with other problems with short-wavelength light that we might help solve,” said Debbie Gustafson, vice president of sales.
Selective deposition of copper interconnect
Nanowire technology could turn out to be useful for selective deposition of copper interconnect at the 22 nm node. Nano Cluster Devices is looking for partners to further develop its process for deposition of pure copper nanoclusters into deep trenches without getting them on surrounding surfaces, thus potentially eliminating polishing steps and avoiding introducing non-uniformities. The nanoclusters are made with a gas aggregation process, where hot metal from a crucible is evaporated into a stream of cool inert gas, where it condenses into droplets that are swept out the nozzle in a showerhead spray onto the wafer at significant velocity. How the balls scatter across the surface and where they come to rest depends on their size and velocity, which can be adjusted to make the clusters bounce off the flat surface and settle into the trench and stick there. “The clusters are very pure copper,” noted Simon Brown, the company’s CTO, “compared to the usual liquid with all that organic gunk you have to get rid of.” The Figure shows clusters that are almost entirely absent from the planar surfaces between trenches.
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| Source: Nano Cluster Devices |
Presently, Nano Cluster Devices is filling 60 nm trenches with its 4 in. demonstration tool. Brown said resistivity values for planar films at least match the 2.2 level of current copper processes so far, and some tests look considerably better, although further testing of trenches is still required.
All of these Technology Innovation Showcase winners will present their innovations on Tuesday, July 17, at SEMICON West at the Emerging Technologies & TechXPOT , located on the 2nd floor of Moscone West, along with other invited speakers to address the latest in nanomanufacturing and materials innovations. Visit www.semiconwest.org to register for SEMICON West 2007 , held July 16-20, at Moscone Center in San Francisco.
