  In this paper, we investigate the manufacturing of vias in integrated
circuits with a new technology combining lithography and Directed Self Assembly
(DSA). Optimizing the production time and costs in this new process entails
minimizing the number of lithography steps, which constitutes a generalization
of graph coloring. We develop integer programming formulations for several
variants of interest in the industry, and then study the computational
performance of our formulations on true industrial instances. We show that the
best integer programming formulation achieves good computational performance,
and indicate potential directions to further speed-up computational time and
develop exact approaches feasible for production.
