Metrology systems and methods

摘要

Various metrology systems and methods are provided. One metrology system includes a light source configured to produce a diffraction-limited light beam, an apodizer configured to shape the light beam in the entrance pupil of illumination optics, and optical elements configured to direct the diffraction-limited light beam from the apodizer to an illumination spot on a grating target on a wafer and to collect scattered light from the grating target. The metrology system further includes a field stop and a detector configured to detect the scattered light that passes through the field stop. In addition, the metrology system includes a computer system configured to determine a characteristic of the grating target using output of the detector.

主权项

1. A metrology system, comprising:
a light source configured to produce a diffraction-limited light beam; an apodizer configured to shape the light beam in an entrance pupil of illumination optics; optical elements configured to direct the diffraction-limited light beam from the apodizer to an illumination spot on a grating target on a wafer and to collect scattered light from the grating target; a field stop configured to reject a portion of the collected scattered light; a detector configured to detect scattered light that passes through the field stop and to generate output responsive to the detected scattered light such that the grating target is measured by the metrology system using scatterometry; and a computer system configured to determine a characteristic of the grating target using the output.