In Depth Understanding of Low-k Dielectric Reliability in Interconnect Systems

Advanced interconnect technologies require the continuous development of reliable low-k dielectric materials and copper/low-k integration processes. One major screening criterion for low-k materials is to have sufficient electrical reliability, while maintaining a low capacitance, a low leakage current and sufficient long dielectric failure time under electrical stress. These are the main parameters to be controlled. The fundamental understanding of intrinsic low-k material properties and the extrinsic influence from integration processes are important to enable an efficient optimization of low-k dielectric material deposition and of each integration step. This PhD work focuses on the in-depth understanding of electrical reliability of advanced low-k dielectrics, where three main objectives are achieved. First, the characterization methods and theories to understand intrinsic conduction and degradation mechanisms in selected low-k dielectrics are proposed. Second, the relationship between low-k dielectric properties, such as porosity and chemical compositions, and the intrinsic conduction and degradation mechanisms is established. In the end, the impact of metallic barrier deposition process on dielectric reliability performance is demonstrated and the mechanisms behind are explained.status: publishe