In order to obtain higher throughput maintaining high precision in the CMP process, it is important to reduce send-ahead work and rework related to film thickness over the within-wafer distribution. This paper presents a new polishing time calculation method that ensures film thicknesses at all measurement positions satisfy the control limit, and gives a judgment on whether send-ahead work is necessary, with the margin of variation of film thicknesses from the control limits after CMP based on the within-wafer distribution of the removal rate and film thickness before CMP. The CMP-APC system applying these methods reduces the defects in film thickness after CMP, along with the amount of send-ahead work, which is half that of the former CMP-APC Run-to-Run control system.

This paper introduces a method of minimizing consumption in order to reduce the running cost of oxide-film CMP processes. Three types of consumables are administrated and replaced based on control limits in use time and monitored removal rate. Typically the control limits are determined separately by consumable. However the combination of consumables' use times takes various effects on removal rate. Therefore, a control limit optimization method to minimize the cost under the condition of removal rate in run-to-run lot works, wherein product lots are processed consecutively on the equipment, is developed. To achieve this, the within-wafer removal rate is modeled based on the use time of consumables, and a run-to-run simulation method to summarize consumption has been developed. The results show that this method could find a new control limit, which reduces the manufacturing cost.

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