Effects of Bias, Pressure and Temperature in Plasma Damage of Ultra Low-k Films

摘要

One of the most critical challenges during the integration of porous low-k materials in ULSI devices is their degradation during plasma treatments. Removal of the carbon containing hydrophobic groups can occur during strip and cleaning processes when exposed to process radicals. Further moisture adsorption leads to the film degradation. In addition, the "field damage" caused by ion radiation during plasma processing can also be problematic. Although these effects are discussed in many papers [1,2], the dominant factors of plasma damage are still a subject of intensive discussions. It has been shown that O2 plasma cause damage manifested as undesirable chemical modification (carbon depletion), while H2 based plasmas have more complicated behavior. Some authors report no effect in low-k films, others that it enhances the film properties, and others indicate severe damage [2].