THE EFFECT OF DEFOCUS ON THE PRINTABILITY OF SUBMICRON 5X RETICLE DEFECTS

The effect of defocus on the printability of sub-micron 5X reticle def ects is assessed by both practical experiment and computer simulation. A specifically designed test reticle incorporating defects whose size , and proximity to adjacent features, varies within sub-micron line/sp ace arrays was printed onto silicon wafer substrates under production conditions. The results were assessed and are presented by plotting mi nimum printed defect (MPD) vs. array linewidth (L/W). Computer simulat ion of the same test reticle was then carried out and similar graphs p lotted. In addition, the results were replotted as curves of MPD vs. d efocus. Finally, the resist modelling program SOLID has been used to c reate 3D images of the printed defects and thus demonstrate the effect caused by defocus on the resist profiles.