The Importance of Copper Integration
-- Semiconductor International, 5/1/2001
More than ever before, the shift to copper device manufacturing requires a rapid and comprehensive integration of the total dual-damascene processing sequence to achieve quick production ramp, as well as optimum device performance and yield. Yet for most IC manufacturers, process integration is a time-consuming and expensive procedure, made even more challenging by the drive to smaller feature sizes and new materials.For example, the filling capability of an electroplating process hinges on the quality of the underlying barrier/seed film stack. Poor morphology, inadequate step coverage and surface contamination can all lead to poor electroplating results - despite having the best electroplating process. A key requirement of a barrier/seed film is a complementary electroplating process window characterization to enable tuning of both processes for optimum fill in a variety of structures and geometries.
Similiarly, a non-optimized post-electroplating anneal step will result in a Cu microstructure that is susceptible to pitting in the subsequent CMP step. CMP, in particular, must deal with all existing conditions from previous steps. Therefore, characterization of the complete metallization process flow, and the ability to separate sequential CMP steps with optimized conditions, allow the rapid development of a CMP process to minimize dishing and erosion.
Equipment suppliers can no longer provide customers with only individual process technologies. They need to have a unique understanding of the compatibility and complex relationships between processes. Customers today are looking for process solutions that can plug seamlessly into their existing process flow without spending much time in learning and optimization. This means delivering a process that is designed, tested, proven and documented to work in an optimized production process flow.
