Measurement system and method for measuring critical dimensions using ellipsometry

摘要

A system (20) for measuring surface features having form birefringence in accordance with the present invention includes a radiation source (28) for providing radiation incident on a surface having surface features. A radiation detecting device (32) is provided for measuring characteristics of the incident radiation after being reflected from the surface features. A rotating stage (22) rotates the surface such that incident light is directed at different angles due to the rotation of the rotating stage. A processor (34) is included for processing the measured characteristics of the reflected light and correlating the characteristics to measure the surface features. A method for measuring feature sizes having form birefringence, in accordance with the present invention includes the steps of providing a surface having surface features thereon, radiating the surface features with light having a first polarization, measuring a reflected polarization of light reflected from the surface features, rotating the surface features by rotating the surface to measure the reflected polarization of the reflected light at least one new rotated position and correlating the reflected polarization to surface feature sizes.