A new SP (simultaneous polishing) model for copper CMP process

For the copper damascene process, dummy fill is used to improve over-polishing problems such as dishing and erosion. Dummy placement based on design rules is ordinary used, but to improve the efficiency of the dummy fill, model-based design is necessary So, we have developed a new SP (simultaneous, polishing) model for Cu-CMP and developed a dummy pattern design system to utilize the model. Using the model, simulation results of dishing and erosion well agree with experiments within 10% errors, and calculation time is fast enough for LSI design. The system we develop can be utilized to design dummy placement practically.