Tribological, thermal and kinetic attributes of 300 vs. 450 mm chemical mechanical planarization processes

An existing 300 mm CMP tool has been modified to polish 450 mm wafers in order to demonstrate experimentally whether any differences exist in the tribological and thermal characteristics of the two processes, and from that, to infer whether one can expect any removal rate differences between the two systems. Results suggest that, within the ranges of parameter investigated, the two systems behave similarly in terms of their coefficients of friction and lubrication regimes. Additionally, it is shown that the 450 mm process, once adjusted for its platen velocity, runs only slightly warmer (by 1-3C) than its 300 mm counterpart. Experimental data, coupled with copper removal rate simulations show that the wafer surface reaction temperature of the 450 mm process is slightly higher (by 1-2C) than the 300 mm process. Consequently, simulated copper removal rates for the 450 mm process are slightly higher (2-13) than those of the 300 mm process at most polishing conditions. The above results indicate that when the current 300mm CMP process is scaled up to 450 mm, the tribological, thermal, and kinetic attributes of the process remain similar and do not undergo significant changes.