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2004 World Technology Awards Winners & Finalists

Dr. Charles Black and Dr. Kathryn Guarini

Please describe the work that you are doing that you consider to be the most innovative and of the greatest likely long-term significance.

For over 30 years, the microelectronics industry has enjoyed substantial integrated circuit (IC) performance improvements based largely on aggressive and continual shrinking of the silicon transistor and metal interconnect dimensions. Future technology generations require increasing innovation beyond traditional scaling in order to continue this performance trend. New materials, device structures, and integration schemes will all play roles in advancing CMOS technology.

Photolithography continues to be the method of choice for patterning IC elements, however as critical dimensions shrink below 100 nm this technique approaches fundamental physical limitations. Material self assembly provides an alternative means for pattern formation at the nanometer-scale. With feature sizes defined by fundamental molecular properties, self assembly can access dimensions and densities beyond the capabilities of conventional patterning techniques.

Self assembly is the spontaneous organization of individual elements into regular patterns. Examples in nature range from snowflakes to sea shells to human beings. Under suitable conditions, certain materials will self organize into nanometer-scale patterns useful for microelectronics applications, evoking the prospect that critical IC elements – or perhaps one day entire circuits – could be made to “assemble themselves.” For integration in microelectronics, it is critical that the self assembling materials be compatible with the existing infrastructure of silicon manufacturing.

For the last five years, we have been fascinated by the beauty and simplicity of self assembling materials and the promise they hold for enabling advances in semiconductor technology. Our work has focused on identifying and demonstrating key applications of self assembly. The diblock copolymer material system is particularly attractive because the polymer constituents – like photoresist materials used in conventional lithography – can act as sacrificial templates for patterning IC elements. Phase separation of the polymer blocks results in formation of ordered patterns with intrinsic molecular-scale dimensions (~10nm) and uniformity determined by the polymer molecular weight distribution. We have integrated these materials as high resolution thin film resists on 200mm diameter silicon wafers and developed etching capabilities for high fidelity transfer of polymer patterns into underlying films for device applications.

These high resolution patterning processes offer innovative solutions to existing challenges in microelectronics. In one example, we enhanced the capacity of thin film metal-oxide-semiconductor devices using nanostructured electrodes patterned by self assembly. Such devices are suitable for on-chip decoupling capacitors, saving valuable chip real estate while buffering the IC against power supply fluctuations. We have also demonstrated the use of material self assembly in facilitating continued scaling of non-volatile FLASH memories, which have become pervasive in technologies such as digital cameras and cell phones. We formed uniformly sized and positioned silicon nanocrystals as the device floating gate, showing the potential for improved reliability and lifetime in FLASH memories. These devices mark the first demonstrations of self assembly in advanced silicon devices.

Today’s ICs can in fact be considered “nanotechnology” since the critical dimensions already reach below 100 nm, a consequence of advances in photolithographic systems and resist materials. Self assembly represents a potential paradigm shift in semiconductor fabrication. We believe that in the near term these materials and processes are well suited to enabling enhanced device performance and functionality by augmenting the available tool kit for manufacturing. At the same time, we will continue to explore novel solutions based on self assembly to address future IC fabrication challenges.

Brief Biography

Dr. Charles (Chuck) Black was born and grew up in Indianapolis, Indiana. He obtained B.S. degrees in Physics and Mathematics from Vanderbilt University in 1991. Chuck received the Ph.D degree in physics from Harvard University in 1996. His thesis research, under Professor Michael Tinkham, investigated electronic energy-levels of metal quantum dots using single-electron tunneling spectroscopy. In 1996 Chuck joined the IBM T.J. Watson Research Center as a Research Staff Member, where he studied prospects for integrating ferroelectric materials for high-density non-volatile memories. In 1999, he transferred to the Physical Sciences Department of IBM Research. Chuck has authored or coauthored 32 technical papers and holds 10 US patents. He is a member of the IEEE, the American Physical Society, the Materials Research Society, and the American Chemical Society.

Dr. Kathryn Wilder Guarini is a Research Staff Member and Manager of the 45nm Front End Integration group in the Silicon Technology department at IBM's T. J. Watson Research Center in Yorktown Heights, NY. Her group’s mission is to evaluate and narrow CMOS device options for the 45nm high performance logic technology node. She also leads IBM’s research team working on three dimensional integrated circuits and explores novel applications of self-assembling materials. Dr. Guarini is author of more than 45 technical publications, including 1 book, and has filed over 15 U.S. patents. In 2003, she was named to the TR100 list of top 100 young innovators by MIT’s Technology Review magazine. She completed her Ph.D. at Stanford University, under the direction of Dr. Calvin Quate, and her B.S. degree at Yale University, both in applied physics. Dr. Guarini is a member of the Institute for Electrical and Electronics Engineers (IEEE), the American Association for the Advancement of Science (AAAS), the Association for Women in Science (AWIS), and Sigma Xi.

Since 1999, Dr. Black and Dr. Guarini have worked closely together exploring applications of nanometer-scale self assembly to microelectronics. They have published extensively in this field and have presented their results at numerous technical conferences, most recently at the 2003 International Electron Devices Meeting (IEDM). Their work has recently been detailed in Scientific American (March 2004) and in numerous national publications (The Wall Street Journal, Reuters, and Associated Press). The New York Times called their method “a new nanoscale manufacturing technique,” and according to News Factor Network they have demonstrated “a molecular-scale technique that promises to simplify the chip-making process and result in more powerful microprocessors.”