Cu CMP with orbital technology: summary of the experience

The Cu process is becoming increasingly attractive as a future choice for IC technology, using Cu both for plugs and wiring. Single and dual Cu damascene includes multiple use of CMP, both for dielectric planarization and removal of excess field material. CMP performance is therefore of extremely high importance for Cu technology. Orbital polishing is known as an effective CMP technique (Bibby et al., Semicond. FABTECH Asia Special, pp. 38-47, 1997). The advantages of this technique are high material removal uniformity (at 3 mm EE), planarization efficiency, high throughput, small footprint, and low cost of ownership. This paper summarizes our experience in Cu-CMP R&D with IPEC's Avantgaard 676 and 776 orbital planarizers. Results on consumable screening, process stability and uniformity, analysis of planarization phenomena for heterogeneous surfaces and data on metal line thinning and dielectric erosion, and discussion of some process integration issues are presented.