Model-Based Double-Dipole Lithography For Sub-30nm Node Device
As the optical lithography advances into the sub-30nm technology node, the various candidates of lithography have been discussed. Double dipole lithography (DDL) has been a primary lithography candidate due to the advantages of a simpler process and a lower mask cost compared to the double patterning lithography (DPL). However, new DDL requirements have been also emerged to improve the process margin and to reduce the mask-enhanced error factor (MEEF), which is to maximize the resolution and image contrast. There are two approaches in DDL i.e. model based and rule based-DDLs. Rule-based DDL, in which the patterns are decomposed by the simple rules such as x- and y- directional rules, shows the low process margin in the 2-dimension (2D) patterns, i.e., line-end to line-end, line-end to bar and semi-isolated bars. In this paper, we first present various analyses of our new model-based DDL (MBDDL) method. Our goal is to maximize the process margin of the 2D patterns.
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