Removal of Adsorbed Moisture and Organics from Surfaces and Nanostructures in Semiconductor Manufacturing

Abstract

As the semiconductor industry is moving towards achieving smaller, denser and faster integrated circuits; the issue of contamination control is becoming increasingly important. The current work focuses on the mechanism and kinetics of removal of adsorbed moisture and organics from surfaces and nanostructures.In the first application of this study, a novel approach to the characterization of dynamic interactions of gases with solid surfaces is developed. A model is developed to represent the simultaneous adsorption and desorption processes in these systems. The model can simulate both the non-equilibrium adsorption and desorption processes as well as the equilibrium state (isotherms and isobars). The model is validated using experimental data, and applied to the adsorption of moisture on oxides (ZrO2 and HfO2). Practical application of this work is shown by optimizing the purge recipes for removal of moisture from a ZrO2 film.In the second application, a novel approach is developed and demonstrated to characterize the sampling line effects during dynamic monitoring of fluid concentrations. The "Sampling line" in this study refers to all components between the point of fluid sampling and the point of analyzer sensor. In general, sampling lines introduce errors in measurements by altering the sample properties due to the fluid transport in the line as well as the adsorption and desorption of fluid constituents on the surfaces of the sampling components that come in contact with the sample fluid. A methodology based on a sampling line simulator is developed for taking these effects into account and correcting the measurements. The sampling line simulator can be used to analyze the effect of various sampling configurations and operating conditions.In the last application, experiments were carried out to study the interaction of organics with micro/nano particles representing nanostructures. A process model is developed which gives insight about the mechanism and kinetics of these interactions. The micro/nano particles, due to their large surface area, can adsorb any other species which may result in the change in their properties. This may ultimately affect the process in which they exist. This study will also be helpful in analyzing the Environment, Safety and Health (ESH) effects of nanostructures.