90nm Contact Hole Study with KrF Process

Abstract

Production feasibility under groundrules smaller than 0.09 um while maintain the cost advantages in KrF exposure tools systems becomes more and more important to all companies including 300mm/200mm FABs. The k1 factor for sub 0.09um with current popular KrF exposure tools will be comprable to 0.028 um at 1.3 NA with 193 nm immersion tools. For line/space patterns, some good results had been achieved. But for contact hole patterns, the patterning is much more challenging. It is the biggest obstacle to transfer all layers patterning from ArF to KrF tools on sub-90nm technology node. In order to improve cotanct holes resoltuion and process window, lots of methods had been proposed in advanced technology. But their manufacturing costs are not satisfied when they are used in 90nm nodes with pure KrF process. In this paper, we will discuss the contact hole patterning with focus tilting technology on 0.82NA KrF scanners. The process window, OPC performance and its issues are discussed. Combine with the line/space pattern results, all layers design rule with KrF process had been pushed to the same level of gerneric ArF process at 90nm nodes.