Applying ILT mask synthesis for co-optimizing design rules and DSA process characteristics

During early stage development of a DSA process, there are many unknown interactions between design, DSA process, RET, and mask synthesis. The computational resolution of these unknowns can guide development towards a common process space whereby manufacturing success can be evaluated. This paper will demonstrate the use of existing Inverse Lithography Technology (ILT) to co-optimize the multitude of parameters. ILT mask synthesis will be applied to a varied hole design space in combination with a range of DSA model parameters under different illumination and RET conditions. The design will range from 40 nm pitch doublet to random DSA designs with larger pitches, while various effective DSA characteristics of shrink bias and corner smoothing will be assumed for the DSA model during optimization. The co-optimization of these design parameters and process characteristics under different SMO solutions and RET conditions (dark/bright field tones and binary/PSM mask types) will also help to provide a complete process mapping of possible manufacturing options. The lithographic performances for masks within the optimized parameter space will be generated to show a common process space with the highest possibility for success.