GOALI - A University/Industry Partnership to Study Reaction and Transport During Depositions from Supercritical Fluids

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

Research: The continuous drive towards smaller and more complex microelectronic devices is placing new demands on the fabrication technologies used for their production. One of the most difficult challenges is the rapid, defect-free deposition of high purity metals within narrow device features with dimensions below 100 nanometers. One prominent example of immediate concern is the fabrication of advanced copper interconnects for integrated circuits. With recent NSF funding, a fundamentally new technique that meets the performance criteria for device metallization, called supercritical fluid deposition (SFD), was developed at the University of Massachusetts. In SFD, soluble organometallic compounds are reduced in supercritical fluids including carbon dioxide to yield high purity deposits at low temperature. A supercritical fluid can be viewed as hybrid medium with properties that lie intermediate to those of gases and liquids. These properties are such that the limitations of current liquid and vapor-phase techniques can be circumvented while preserving the benefits of each. The result for Cu deposition is unprecedented feature fill at sub-100 nm device dimensions, while maintaining other critical film properties. The PI's results to date indicate SFD offers great promise for the fabrication of semiconductor and other devices, but the technique is still in its infancy and fundamental studies are required to further development and broaden its impact. Toward this end, the PI will examine two issues that are essential to understanding SFD and related SCF processes. First, the mechanisms for SFD reactions will be determined and models that capture both deposition kinetics and step coverage will be elucidated. Knowledge of reaction pathways during SFD will have direct implications for device metallization and broader impact for catalytic reactions in supercritical media. Second, computation fluid dynamics (CFD) simulations will be developed to describe heat and mass transfer in multi-component supercritical deposition reactors under highly turbulent flow. These capabilities are not accessible in commercial packages and will be invaluable for a broad range of SCF applications. Experimental data will be used to validate and refine the models. Impact: The research program is a cooperative effort between the University of Massachusetts and Novellus Systems, a leading semiconductor equipment company that has licensed SFD for microelectronic applications. It will facilitate the development of SFD for interconnect technology, which may prove enabling for future generations of integrated circuits, a $100 billion / yr. industry. Success will result in the transfer of academic research to commercial applications while eliciting fundamentals of reaction and transport in SCFs that have broad relevance to a number key industries. The program will also provide a unique opportunity for graduate students to work at the interface of industry and academia.