Comparing the economic impact of alternative metrology methods in semiconductor manufacturing

Metrology is an essential part of advanced semiconductor manufacturing. It accelerates yield improvement and sustains yield performance at every stage in both new and mature processes. Advances in metrology are needed to achieve challenging industry goals, such as smaller feature sizes and reduced time for introduction of new materials and processes for future technology. To achieve difficult industry goals, it is expected that metrology practices will migrate from offline to inline, and ultimately, to in situ. Economic models are needed to study the costs and benefits of introducing new metrology technologies and to compare alternative metrology practices. Several qualitative and quantitative models are presented in this paper to study the elements of revenue and cost associated with different metrology tools and practices. Comparisons between in situ, inline and offline metrology systems are made. The cost components of the metrology methods are analyzed and discussed with respect to steady state process control as well as their effect on time to yield. Monte Carlo simulation models are used to study each system under different scenarios.