A phase shifting mask (PSM) and a trim mask can be used in a dual exposure to form circuits on an integrated circuit. The trim mask can include first structures that define non-critical features of a design (e.g. line ends), second structures that protect areas exposed by phase shifters, wherein such areas including critical features (e.g. transistor gates) of the design, and transitional areas located between the first and second structures. Notably, these transitional areas can include notches. This notched trim mask can advantageously minimize line end widening, thereby improving feature definition and device performance on the resulting integrated circuit. The notched trim mask can also advantageously simplify the optical proximity correction of its associated PSM, thereby minimizing fabrication costs.