Lotte Willems

Multi-patterning lithography at the 10-nm and 7-nm nodes is driving an exponential increase of metrology complexity in the overlay and alignment tree. Coupled with the highly involved process stacks required to reach these nodes, the setup and verification of the metrology recipes have reached new levels of importance. With an all-encompassing holistic mindset the authors present four node-enabling technologies using production data from a leading logic customer. Firstly an optimized layout is… Meer weergeven

Multi-patterning lithography at the 10-nm and 7-nm nodes is driving an exponential increase of metrology complexity in the overlay and alignment tree. Coupled with the highly involved process stacks required to reach these nodes, the setup and verification of the metrology recipes have reached new levels of importance. With an all-encompassing holistic mindset the authors present four node-enabling technologies using production data from a leading logic customer. Firstly an optimized layout is defined using a metric that ranks the importance of available wafer coordinate positions based on the model to be use for lithographic apparatus actuation. Next to minimize influence of process induced target asymmetry on overlay, the authors define how to find the optimum wavelength and polarization settings for overlay metrology. Once the process has reached a high volume-manufacturing (HVM) environment, we propose a method of monitoring using a single point key performance indicator (KPI). In the last section all learning is applied with integrated metrology (IM) within HVM to realize improved correctable error in measured overlay. Minder weergeven

Multi-patterning lithography at the 10-nm and 7-nm nodes is driving the allowed overlay error down to extreme low values. Advanced high order overlay correction schemes are needed to control the process variability. Additionally the increase of the number of split layers results in an exponential increase of metrology complexity of the total overlay and alignment tree. At the same time, the process stack includes more hard-mask steps and becomes more and more complex, with as consequence that… Meer weergeven

Multi-patterning lithography at the 10-nm and 7-nm nodes is driving the allowed overlay error down to extreme low values. Advanced high order overlay correction schemes are needed to control the process variability. Additionally the increase of the number of split layers results in an exponential increase of metrology complexity of the total overlay and alignment tree. At the same time, the process stack includes more hard-mask steps and becomes more and more complex, with as consequence that the setup and verification of the overlay metrology recipe becomes more critical. All of the above require a holistic approach that addresses total overlay optimization from process design to process setup and control in volume manufacturing. In this paper we will present the holistic overlay control flow designed for 10-nm and 7-nm nodes and illustrate the achievable ultimate overlay performance for a logic and DRAM use case. Minder weergeven