Selectivity switch concept in Cu chemical mechanical planarization and itsimplementation on orbital tools

Cu and barrier removal peculiarities were studied and a differential multis lurry (DMS) chemical mechanical planarization (CM) process for dual damasce ne technology was developed. Process shows Cu removal rates up to 1.2 mu m/ min with an average nonuniformity <5%. Annealing was shown to have impact o n process stability. Details of Cu removal mechanism were studied. Cu remov al process was found to be temperature insensitive and following Preston's law that indicates its pseudo-mechanical nature. Abrasive enhancement of ch emical activity was shown to be important for Cu removal. Phenomenon of met al feature thinning (MT) and dielectric erosion (DE) in heterogeneous CMP w as analyzed and compared with data obtained fur various conditions. It was shown that properties of all major acting CMP characters: the tool (loading ), the slurry (selectivity), and the pad (hardness) are contributing to MT. Hard pad, slurry selectivity less than or equal to 1 in the end of Cu clea rance phase and low polishing pressure help to minimize MT. Some MT and DE related process integration issues are discussed, as well. (C) 1999 America n Vacuum Society. [S0734-211X(99)07905-6].