Due to the delay of next generation lithography technologies, multiple patterning lithography technologies are still the most promising solutions for sub-20nm technology nodes. To enhance pattern printability, one-dimensional grid-based layout structure will be adopted, which can be achieved with a self-aligned multiple patterning (SAMP) process followed by a trim process. However, trim masks for arbitrary layouts have very low manufacturability because their resolution is limited by conventional 193nm lithography. In this paper, we propose the first work that adopts litho-etch-litho-etch double patterning lithography for the trim process. We first propose a stitch finding approach for complicated polygonal trim patterns, and then an integer linear programming (ILP)-based layout decomposition algorithm is proposed considering color balancing. Experimental results demonstrate the effectiveness of the proposed algorithms.