Manufacturability of rapid-thermal oxidation of silicon: oxide thickness, oxide thickness variation, and system dependency

The dependence of oxide thickness, and oxide thickness variation within a wafer and wafer-to-wafer on process variables was studied in rapid-thermal processing systems that differed in chamber configuration and construction, incoherent light source, and pyrometers used for temperature measurement. Mechanisms for oxide growth and oxide thickness variation in rapid-thermal oxidation are discussed. Thermally induced stress, lamp configuration, and convective cooling affected the oxide thickness variation within a wafer. Wafer-to-wafer oxide thickness variation depended on the material of chamber construction, quartz or metal, and was related to residual heating for longer oxidations. For the same processing conditions, the oxide thickness was different for different systems, due to temperature error and a photonic component to rapid-thermal oxidation. Analysis of empirical oxide thickness models revealed a silicon orientation effect and a mechanism related to oxidant transport that was common to rapid-thermal oxidation in different systems