OPTIMIZING TUNGSTEN CMP IN THE AGE OF COPPER

摘要

In a tungsten (W) plug/copper (Cu) damascene interconnect scheme, the requirements for dishing and erosion at the W plug CMP process can be significantly more stringent than for a similar aluminum scheme. Data will be presented that compares the physical measurements for dishing and erosion as a function of feature size. This will be shown on both flexible and solid platen, and for different process conditions including down force, carrier speed, slurry flow and time. It will be shown that the dishing and erosion is larger for the flexible platen and a higher down force process. Electrical data and inspection results will also be presented showing the impact of the erosion on subsequent metal resistance and bridging.