Abstract
The advantages gained by the use of a multilayer resist system were examined by electrical linewidth measurements of polysilicon lines ranging in width from 0. 7 to 1. 0 mu m. Multilayer resist was compared to single-layer resist and quantitative data was obtained regarding the theoretical advantages of reduced reflectivity, improved planarity, and thinner imaging resist inherent to a multilayer resist system. Two different thicknesses of single-layer resist revealed that a thinner imaging layer resulted in improvements of up to 15% for linewidth variation and 35% for depth of focus. Reducing reflections from the substrate from 33% to 3. 5% led to improvements of up to 30% in linewidth variation and depth of focus. Introduction of a particular type of topography under the polysilicon led to a worsened linewidth variation and depth of focus, by up to 30%.