Plasma etch tool selection criteria for minimizing cost of ownership

As capital requirements for new integrated circuit factories increase, cost of ownership for the wafer factory equipment becomes increasingly important. Utilization of a mix-and-match equipment strategy in lithography, combining critical and noncritical tools has been used as a technique to increase productivity. Despite the success of mix-and-match lithography strategies, the application of this strategy for etch tools has lagged. The requirements of the specific etch processes can be evaluated to determine the suitability of noncritical tool applications to meet the process requirements. Tool cost ratios and cost of ownership calculations are used to determine the potential savings in terms of capital outlays and wafer costs. It was found that potential savings of 10-26% could be achieved using the critical/noncritical etch tool selection strategy.