Application of Run by Run controller to the chemical-mechanical planarization process. I

The Run by Run (RbR) controller, combining the advantages both statistical process control (SPC) and automatic process control (APC) has been applied successfully to a technically mature epitaxy processes and is now being applied on the chemical-mechanical planarization (CMP process). Three quality metrics are defined and used as measurements of process improvement. The application procedure is divided into five stages, of which the implementation stages one and two have been performed. The data show that a system can be described by an equilibrium state, a transition period responsive to shifts in the input, but exhibiting substantial hysteresis. A transition period between different equilibrium states is clearly observable. The memory that the pad has due to previous recipe is also clearly demonstrated