Reduced oxide reliability due to multilevel metalization process

The effect of multilevel metalization process on oxide reliability was investigated. In addition to the well-known charging damage from plasma etching, other types of damages were identified. They are non-electrical damage due to ILD process, and charging damage due to plasma oxide deposition. Recovery effects of plasma induced charging damage were also observed. Since the damage responds differently to measurement depending on the stress bias condition, an appropriate choice of stress condition is important to identify the nature of the damage.