| Summary: | 博士 === 國立清華大學 === 材料科學工程學系 === 90 === The applications of plasma techniques used in diamond synthesis and silicon etching have been investigated in this study. The Taguchi method and the response surface methodology (RSM) were used to analyze the effect of various control factors and optimize the processes parameters. In group IV, diamond composed of carbon element is a unique and fascinating material due to its wide range of extreme properties, and silicon has been widely used by today''s semiconductor industry. In the part of diamond synthesis, the Taguchi method with an L18 orthogonal array design has been used to investigate the effect of various control factors on the performance of microwave plasma enhanced chemical vapor deposition (MPECVD) diamond films. The phenomena of diamond synthesis on molten metals substrates resulting from high carbon concentration conditions were observed. The results suggest that there may exist a low methane content boundary layer in the proximity of molten metal surface on which suitable species are composed. Furthermore, a commercially available process of electroless nickel plating with co-deposited diamond powders was applied to the steel substrate as an intermediate layer for tribological applications. The growth phenomena of diamond grits from both gaseous and solid carbon sources were also investigated. In the part of silicon etching, RSM is used to investigate the effect of various control factors on the performance of silicon trench etch in high-density transformer coupled plasma (TCP) on Cl2/HBr/O2-based chemistry. Quantitative relationships between etching characteristics and process parameters have been established. The possible mechanisms are also proposed to explain the different sidewall profile angles as varying the parameters. The feasibility of simultaneously etching n+, p+, and undoped polysilicon (poly-Si) materials by a commercial TCP reactor has been also investigated in this study. The results indicate that a suitable process window would meet the requirements of etching polysilicon with different doping types simultaneously. In this study, high etch rate, superior uniformity, only fewer minor plasma induced damages, good end point detection (EPD) characteristics and profile control can be obtained with the optimized recipe.
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