| 초록 |
Since the past decades, electronic devices have been developed and transformed into the shape of what humans wanted. During this time, the main goal of each project was scaling down the size of transistors, which was developed in semiconductor physics research area. However, the size of transistor was limited in nanometer scale, thus caused researches to study different materials that can replace interconnect material for higher performance. Copper (Cu) has been studied in many research areas to replace Aluminum (Al) as multilevel interconnect due to its high electrical conductivity and electromigration resistance. However, Cu is more diffusive, which can create traps in bandgap that degrade performance of device, so diffusion barrier was needed in between Cu and SiO2. Although there were many materials that can function as diffusion barrier, the thickness was too thick. While studying other materials for diffusion barrier, we found out that Self-Assembled Monolayer (SAM) can function as barrier. Organic SAM molecules were deposited onto Si/SiO2 wafer and tested its functionality using Atomic Force Microscopes (AFM), Angle Resolved X-ray Photoelectron Spectroscopy (AR-XPS), and Time Dependent Dielectric Breakdown (TDDB), and the result demonstrated that organic SAM molecules make organic pattern among themselves. Through experiments we have done, we were able to prove that some SAM molecules worked as diffusion barrier were due to organic pattern occurred among themselves. The lifetime of SAM molecule with larger organic pattern lasted about 2-3 times longer compare to that of molecule with smaller organic pattern. The thickness was still ~2 nm scale with the roughness of 0.5 RMS. The theory was confirmed through those experimental results. |
