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Published: 1996

Total Pages: 12

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A critical step in the fabrication of integrated circuits is the deposition of metal layers which interconnect the various circuit elements that have been formed in earlier process steps. In particular, columns of metal 2-3 times higher than the characteristic dimension of the circuit are needed. At the time of initiation of this CRADA, the state-of-the-art was the production of 1-1.5 micron-high columns for 0.5 micron-wide features with an expected reduction in size by a factor of two or more within five to ten years. Present commercial technologies cannot deposit such features with the process temperature, aspect ratio (ratio of height to diameter), and/or materials capability needed for future devices. This CRADA had the objective of developing a commercial tool capable of depositing metal (either copper or aluminum) at temperatures below 300°C into features with sizes approaching 0.2 micron on 200-mm wafers. The capability of future modification for deposition of alloys of controllable composition was also an important characteristic. The key technical accomplishments of this CRADA include the development of a system capable of delivering highly ionized metal plasmas, refinement of spectroscopic techniques for in situ monitoring of the ion/neutral ratio, use of these plasmas for filling and lining submicron trenches used for integrated circuit fabrication, and generation of fundamental data on the angular dependent sputtering yield which will prove useful for modeling the time evolution of feature filling and lining.