Materials modeling and development for use in double-exposure lithography applications

The current optical photolithography technology is approach- ing the physical barrier to the minimum achievable feature size. To pro- duce smaller devices, new resolution enhancement technologies must be developed. Double-exposure lithography has shown promise as a potential pathway that is attractive because it is much cheaper than double-patterning lithography and can be deployed on existing imaging tools. However, this technology is not possible without the development of new materials with nonlinear response to exposure dose. The perfor- mance of existing materials such as reversible contrast enhancement layers ! rCELs" , and theoretical materials such as intermediate state two- photon ! ISTP" and optical threshold layer ! OTL" materials in double- exposure applications have been investigated through computer simula- tion. All three materials yielded process windows in double-exposure mode. OTL materials showed the largest process window ! depth of focus ! DOF" 0.14 ! m, exposure latitude ! EL" 5.1%" . ISTP materials had the next-largest process window ! DOF 0.12 ! m, EL 3.2%" , followed by the rCEL ! 0.11 ! m, 0.58%" . This study is an analysis of the feasibility of using the materials in double-exposure mode. © 2009 Society of Photo-Optical