Effects of measured spectral range on accuracy and repeatability of OCD analysis

摘要

There is a need for metrology to help control manufacturing processes for power semiconductors, where deviations from the desired structure geometry can affect device performance. Lithography and etch processes, specifically, create patterned structures, where the trench depth and width, or CD (critical dimension), must be tightly controlled. Traditionally, several techniques have been employed for this purpose, including cross-section Scanning Electron Microscopy (SEM), CD-SEM, prof ilometry, and Atomic Force Microscopy (AFM). Each method has its benefits and limitations, but none can provide detailed profile information with the combination of speed and measurement sensitivity of non-destructive optical metrology, based on broadband polarized reflectometry.