Various embodiments provide for inserting an etching shape in a circuit design based on one or more spacing rules, which can be part of electronic design automation (EDA). Some embodiments described herein address wire-end spacing violations for abutted cell placements by enabling one or more etching shapes to be inserted during block implementations, without needing to insert the etching shape at a top level of a circuit design. Additionally, some embodiments described herein address violations of one or more height rules by supporting variable trim height while ensuring that no new violation is introduced with a new etching shape.

A system for target centering detection may be configured receive one or more acquisition images of a sample from an overlay metrology sub-system and determine, using a machine learning-based centering model, one or more stage correctables based on the received one or more acquisition images. The system may be configured to cause a sample stage of the overlay metrology sub-system to adjust a stage position based on the determined one or more stage correctables and receive one or more measurement images of the sample from the overlay metrology sub-system based on the adjusted stage position of the sample stage. The system may then be configured to determine one or more overlay measurements based on the received one or more measurement images.

A metrology system for imaging samples such as semiconductor devices having metrology targets for measuring overlay. In embodiments, a multi-channel imaging system is configured to image two relevant spaced layers of a sample simultaneously at the same magnification using a common detector. In embodiments, the multi-channel imaging system includes a first imaging light for imaging the metrology target at a first depth, and a second imaging light for imaging the metrology target at a second depth, wherein the first and second imaging lights are generating by splitting collected light from the sample, and wherein first and second sub-images associated with the respective first and second imaging lights are used to generate metrology measurements.