Robust Trilayer Patterning Technique

This paper presents the results of efforts to achieve a very wide processing window lithography using a spin-on trilayer patterning stack. Materials design and processing are based on physical and chemical properties as well as optical field distribution and focus on molecular forces between resist and substrate. All of these factors closely affect line edge roughness/line width roughness (LER/LWR) and critical dimension (CD) processing window (PW). The technique aims to provide an extremely wide CD PW for producing lines and contact patterns in a single lithographic process. The wide depth of focus (DOF) performance allows the printing of difficult patterns having low image contrast, simplifying optical proximity correction (OPC) and source mask optimization (SMO) to make patterning more robust. Scanning electron microscope (SEM) cross sections of the lithography results are presented, and these results are compared to optical simulations.