To determine the effect of wafer stepper resolution on the printability of reticle defects, a test reticle containing edge-related submicron programmed defects was printed using 0.35, 0.43, 0.45 and 0.54 NA g-line 5x steppers. The size of the minimum printable defect was determined by examining the wafer photoresist images using both optical and scanning electron microscopes. Photographs show the effect of submicron defects located on or near geometry edges. Submicron reticle defects affected critical dimensions, image profiles and resist thickness in a 1.5 λ/ NA diameter "sphere of influence" on the wafer. The higher resolution, higher NA steppers printed smaller defects. Defocus was observed to increase the damage caused by printed defects.
James N. Wiley, James N. Wiley,
"Effect of Stepper Resolution on the Printability of Submicron 5x Reticle Defects", Proc. SPIE 1088, Optical/Laser Microlithography II, (25 July 1989); doi: 10.1117/12.953134; https://doi.org/10.1117/12.953134