Statistical Analysis of Novel Dielectric Materials for Microelectronics

Abstract

This research analyzes the re-oxidation annealing process of Barium titanate thin films on copper foils made by Chemical Solution Deposition. During this anneal, the temperature and oxygen pressure settings must be optimized to ensure the elimination of oxygen vacancies without oxidizing the copper foil substrate. This research utilizes Design of Experiments (DOE) to study the impact of re-oxidation furnace temperature and pressure on the dielectric loss tangent response. Two designs of experiments were run. The first experiment, a 32 DOE, examined a large range of temperature and pressure levels. Due to the high susceptibility of uncontrollable factors such as humidity and film position in the crystallization anneal furnace, an adequate model could not be developed. However, the temperature at 550°C and a pressure of 10-5 Torr yielded a lower mean and standard deviation of the loss tangent response. A second and smaller scale experiment, a 22 with a center point, was run around 550°C and 10-5 Torr to determine if more optimal temperature and pressure settings existed in the local area. Two second order response surface models were developed from two crystallization anneals that were statistically significant. The most significant finding was that the optimum level for temperature and pressure in the re-oxidation anneal furnace in this experiment is 550°C and 2x10-5 Torr. While the models concluded that the temperature, pressure, temperature quadratic, and interaction between pressure and temperature were important effects in the model, there were differences in the curvature of the models due to the temperature quadratic effect.