The Analysis of Optical Critical Dimension (OCD) Signal Strength Between 5 nm FinFET and 3 nm Complementary FET (CFET) Vertical Gate Stacks

The use of Optical Critical Dimension (OCD) technique to characterize the optical properties of periodic semiconductor structures, has achieved great success in semiconductor manufacturing over the past decades. OCD is an indirect and nondestructive optical metrology, in which physical properties of a sample is obtained through optical scattering spectra and modeling simulation. As in-line measurement of three dimensional (3D) structures is more and more critical in semiconductor manufacturing, the improvement of the accuracy and sensitivity for the latest 3D architectures has become inevitable. This article will provide an analysis of OCD Signal Strength for both 5 nm FinFET and 3 nm Complementary FET (CFET) architectures, and provide some insight and advise for OCD modeling in advanced technology nodes.