Lens Stepper Macro Defects

A lens stepper macro defect may look similar to a reticle tilt caused macro defect. Lens stepper caused macro defects on the wafer typically shows a difference within the stepper shot (center of the lens field is different than the edge of the lens field) while the reticle tilt caused macro defect goes across a stepper shot. The lens stepper macro defect can be due to a variety of problems; dirty lens, malfunctioning i-line filter, an incorrect reticle throughout rate in the stepper job or other causes.

This is another example of a lens stepper macro defect taken by EAGLEview.