Lens Array-Based Illumination for Wafer Inspection

摘要

Systems configured to provide illumination for wafer inspection performed by a wafer inspection tool are provided. One system includes one or more pupil lenses configured to focus a first far field pattern having a shape different than a shape of light generated by a light source. The system also includes a field lens array positioned between the one or more pupil lenses and an aperture stop. In addition, the system includes a lens group configured to focus a second far field pattern generated by the field lens array to a back focal plane of the lens group. The back focal plane of the lens group is a field plane of a wafer inspection tool at which a wafer to be inspected is placed during wafer inspection.

主权项

1. A system configured to provide illumination for wafer inspection performed by a wafer inspection tool, comprising:
a light source configured to generate light; one or more pupil lenses configured to generate a first far field pattern of the light having a shape different than a shape of the light generated by the light source; a field lens array positioned between the one or more pupil lenses and an aperture stop positioned proximate to the field lens array, wherein the field lens array is configured to generate a second far field pattern of the light having a cross-sectional shape that is substantially the same as a cross-sectional shape of each individual lens in the field lens array; and a lens group, wherein the aperture stop is placed between the field lens array and the lens group, wherein the lens group is configured to focus the second far field pattern to a back focal plane of the lens group, and wherein the back focal plane of the lens group is a field plane of a wafer inspection tool at which a wafer to be inspected is placed during wafer inspection such that the wafer is illuminated with the second far field pattern.