Measuring complex structures in semiconductor fabrication

Abstract

Measuring SRAM structures having FinFET transistors by obtaining, on a production semiconductor wafer, spectra of a SRAM production structure including FinFET fins and gates, identifying SRAM reference structure spectra corresponding to the spectra, the reference structure from measuring, on a reference semiconductor wafer, a reference structure including a layout of FinFET fins having gates, injecting, into an OCD model of the production structure, fin target parameter values, corresponding to the identified reference structure spectra, from measuring, on the reference wafer, a fin target including a layout of exposed FinFET fins lacking gates similar or identical to the reference structure layout, correspondence between the fin target parameter values and the reference structure spectra previously identified by ML, and determining measurement values for the FinFET gates of the production structure by fitting reference spectra associated with the production structure in the OCD model to the production structure spectra.