The performance of electrical circuits depends highly on the overlay of the actual device. However, overlay metrology is typically performed on dedicated non-device structures as proxy for device. In this paper, we show that an overlay metrology system based on high voltage scanning electron microscope (HV-SEM) can be used to measure the overlay errors of devices of any shape using a die-to-database (D:DB) algorithm. The D:DB algorithm uses the design-intent of multiple layers, in the form of database clips, to extract overlay errors for patterns of any shape. The D:DB algorithm can account for edge-over-edge effects as well as multiple visible layers at once. This enables accurate overlay measurements, even for complex devices, while simultaneously reporting overlay for multiple layer pairings. We show that this method of device measurement can be used to compare how the overlay error reported by different target designs matches the overlay error of the device structures itself.
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