Phi-scatterometry for integrated linewidth control in DRAM manufacturing

Abstract

A cost-effective scatterometry method is presented which is suitable for integrated linewidth control and which is a supplement to conventional SEMs. The phi-scatterometry procedure is carried out directly on periodic functional patterns instead of using additional test structures. Long-term simulations of diffraction effects are not required. The measurement results are evaluated by neural networks performing classifications of pattern parameters. Thereby, fast fault detection and immediate process control is enabled. A phi-scatterometry prototype was built for flexible mobile metrology in 300-mm production environments. The measurement principle was verified with DRAM patterns having trenches in two dimensions.