Enhancing critical dimension measurement with nanometer scale using CNNs and optical theory-derived 3D point spread function

Optical image metrology is vital in semiconductor manufacturing, offering non-contact, high-resolution, high-speed measurements. This AI-driven approach integrates CNN with a physics-based 3D point spread function (PSF) for enhanced critical dimension (CD) measurement. A focused ion beam (FIB) artifact captures the PSF, while imaging noise is minimized using a parameterized 3D PSF from the Gibson-Lanni model with Zernike polynomials. A super-resolution CNN with Wiener deconvolution refines resolution. Preliminary experimental results show this method doubles the depth of field (DOF) and enables nanometer-accurate CD measurement, improving semiconductor manufacturing and automated optical inspection (AOI).