Neutron probes focus the search for insulators. (News Briefs).The semiconductor industry is desperately seeking better insulating materials. By the end of the decade, state-of-the-art integrated circuits Integrated circuits Miniature electronic circuits produced within and upon a single semiconductor crystal, usually silicon. Integrated circuits range in complexity from simple logic circuits and amplifiers, about 1/20 in. (1. will contain more than a billion transistors, connected by thousands of meters of ultra-fine copper wiring. Without satisfactory replacements for silicon dioxide silicon dioxide: see silica. (SiO2) A hard, glassy mineral found in such materials as rock, quartz, sand and opal. In MOS chip fabrication, it is used to create the insulation layer between the metal gates of the top layer and the silicon elements below. , the current insulator of choice, the potential for electrical cross talk between such closely packed wires will be enormous. Recently, the search has become less frenzied and more focused, thanks to a productive collaboration between NIST (National Institute of Standards & Technology, Washington, DC, www.nist.gov) The standards-defining agency of the U.S. government, formerly the National Bureau of Standards. It is one of three agencies that fall under the Technology Administration (www.technology. and International SEMATECH SEMATECH Semiconductor Manufacturing Technology , the consortium of chip makers and equipment suppliers. The team has pioneered the use of powerful analytical methods to gather critical information on the properties of a promising and extremely varied class of insulators: thin films with nanometer-scale pores. The pore structure lowers the so-called dielectric constant dielectric constant n. See permittivity. of the films to desired levels. Unfortunately, the Swiss-cheese-like effect can undermine other important properties--from mechanical strength to hardness to thermal expansion--that strongly influence the suitability of the films for semiconductor manufacturing. Working at the NIST Center for Neutron Research, the team is using small-angle neutron scattering Small angle neutron scattering (SANS) is a laboratory technique, similar to the often complementary techniques of small angle X-ray scattering (SAXS) and light scattering. These are particularly useful because of the dramatic increase in forward scattering that occurs at phase to characterize a growing cast of nanoporous, low-k dielectric films. With the tools, researchers can measure average pore size, pore distribution and connectivity, film thickness and composition, coefficient of thermal expansion coefficient of thermal expansion, n See expansion, thermal coefficient. , and other important characteristics of samples. NIST has evaluated an assortment of nanoporous films supplied by International SEMATECH. These include spun-on glass materials, films from chemical vapor deposition Vapor deposition Production of a film of material often on a heated surface and in a vacuum. Vapor deposition technology is used in a large variety of applications. and organic thin films. Structural information provided by NIST is placed into a master database, where it is combined with other data needed to evaluate candidate materials. Materials and equipment suppliers also are leveraging the NIST-provided measurements to engineer novel nanoporous films with even more complex microstructures, broadening the search for economical, high-performance low-k dielectric films. An overview of this project and others in the Interconnect and Packaging Metrology Program can be found at www.eeel.nist.gov/omp/interconnect.html. For technical information, contact Barry Bauer, (301) 975-6849, barry.bauer@nist.gov, Eric K. Lin, (301) 975-6743, eric.lin@nist.gov or Wen-li Wu, (301) 975-6839, wen-li.wu@nist.gov. Media Contact: Mark Bello, (301) 975-3776; mark. bello@nist.gov. |
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