SBIR Phase I: Diffusion Resistant, High Purity Wafer Carriers

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9661246 Leaskey This Small Business Innovation Research Phase I project involves the processing of Si wafers for semiconductor applications to eliminate or reduce contamination by undesirable metal ions. A major source of impurities has been identified as the wafer carriers used in the high temperature processing. Although carriers with high purity surfaces are available, with use the surface purity levels significantly decrease because: (1) higher purity CVD coatings spall and exposure lower purity bulk material and/or (2) contaminants in the bulk diffuse with time and temperature to the surface. At wafer processing temperatures above ~1100 C, SiC-Si carriers are used. The presence of Si increases the potential for contamination due to the high diffusion coefficients of many metal ions through Si, which are often many orders of magnitude greater than for SiC. It would be desirable to replace the Si phase with a component through which ion mobility is decreased. An innovative composite is proposed which has the potential for long-term use without contamination and improved mechanical properties. The components will be completely analyzed for relevant properties including purity and mechanical properties. Demonstration of fabrication of high quality components would lead to more extensive analyses of prototype components to determine long term performance. The main application would be as diffusion components to be used in semiconductor processing. The composites could also be fabricated with lower purity levels and used for applications requiring high temperature, corrosion resistant materials such as engine and heat exchanger components.