Investigation of Evolution Processes of Wafer Profiles With Edge Over Erosion in Copper CMP

In this paper, the causes of edge over erosion (EOE) in copper CMP are investigated. Wafer patterns containing square-wave features with pattern density of 50% and line width of 0.18, 0.5, 1, and 2 μm are studied. The evolution processes of wafer profiles with EOE of the pattern structures are simulated by using frequency components algorithm (linear system method). The wafer profiles of the pattern structure of 0.18 μm at different polishing time are given. The results of the simulation of EOE, erosion and dishing of the pattern structures are compared with the experimental data. The effects of polishing parameters on the evolution process of height of ear profile, loss of Cu, erosion, dishing, height of area 1 of the different patterns are discussed. The methods to reduce the value of EOE and loss of Cu are provided.