Pattern shift response metrology

Designed asymmetry amplifies mark centroid sensitivity to variation in pattern dimensions. This enhanced pattern shift response (PSR) enables optical metrology precision to scale inversely with pitch. Embedded bias steps reference the measured PSR variance to design, allowing the PSR to be expressed as an equivalent Design Referenced Deviation (DRD). The shift-to-design correlation slope monitors the evolution of patterning fidelity throughout the process. PSR metrology on ground-rule compatible marks is applied to an example of advanced-node first-metal processing, including EUV lithography, trench etch and CMP.