Overlay Metrology Method

Abstract

An overlay metrology method includes illuminating an overlay grating target with a polychromatic beam and collecting intensity information associated with a diffraction spectrum produced by the overlay grating target from the polychromatic beam. The diffraction spectrum separates the polychromatic beam into a plurality of diffracted beams, each of the plurality of diffracted beams corresponding with a respective wavelength of the polychromatic beam. The method further includes generating overlay information from the collected intensity information associated with the diffraction spectrum, wherein the overlay information includes contributions from asymmetry-induced overlay error.

Description

technical field [0001] Embodiments of the present disclosure relate to overlay measurements related to the manufacture of integrated circuit devices, and in particular to spectral overlay measurements. Background technique [0002] As integrated circuit technology continues to evolve to smaller dimensions, integrated circuits become more challenging. For example, integrated circuit design includes combining a series of patterned layers and un-patterned layers to form one or more integrated circuit features. The misalignment between different integrated circuit layers will cause performance problems due to the short circuit phenomenon caused by multiple misaligned integrated circuit layers, and may even cause damage to the integrated circuit device. Therefore, the coverage of different integrated circuit layers (generally referred to as the positioning of integrated circuit layer and integrated circuit layer) is so important to ensure the correct function of integrated circu...

AI Technical Summary

Problems solved by technology

While overlaymetrology techniques are generally adequate for their intended purposes, the problem of quickly and accurately assessing coverage of advanced technology nodes has not been fully met

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