Methods for comparing contact hole shrinking techniques with 248 nm single layer and bilayer photoresists

Abstract

Several contact hole shrinking techniques have been discussed in the literature recently. Two notable techniques; Resolution Enhancement Lithography Assisted by Chemical Shrink (RELACS™) and Resist Flow Process (RFP) were investigated in conjunction with several commercially available high activation energy chemically amplified materials and one bilayer material. During the course of this study the unique set of advantages along with the inconveniences associated with each technique were explored. It was not only the lithographic attributes of each technique that were of interest, but also characteristics that would effect manufacturability. To that end, experiments were designed so that standard statistical techniques could be employed at the data analysis stage. The attributes of interest were the amount and control of shrinkage, nested and isolated feature bias, process window comparisons, and line edge roughness. It will be shown how several of theses attributes are directly related to manufacturing issues such as lot-to-lot repeatability andlinewidth variations across the wafer.