<title>Application of deep-UV attenuated PSM to 0.2-um contact hole patterning technology</title>

Abstract

In order to develop 1 G bit DRAM of 0.18 micrometers design rule, it is required to generate 0.2 micrometers contact hole patterns with local DOF over 1.0 micrometers . One of good candidates is DUV attenuated phase shift mask (PSM), which improves the lithographic process margin such as depth of focus (DOF), especially in contact hole patterns due to edge enhancement effect. In the case of DUV attenuated PSM, the optimum condition for contact hole patterns near 0.2 micrometers has been investigated by simulations and experiments using chromium- based attenuated PSM with the transmittance of 6% at 248 nm wavelength. We obtained local DOF of 1.2 micrometers for 0.2 micrometers contact hole of 1 G bit DRAM with printing bias of -0.046 micrometers using KrF laser system (0.31 (sigma) , 0.55 NA). We evaluated the characteristics of contact hole with various duty ratios and defect printability using programmed defects.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.