1. A method for laying out an opaque field, alternating phase shift mask pattern and a trim mask pattern for use with the phase shift mask pattern to produce a target feature, the phase shift mask pattern including a first phase shift window having a first side and a second side opposite the first side and spaced away from the first side by a first phase shift window width, a second phase shift window with complementary phase, having a first side and a second side opposite the first side and spaced away from the first side by a second phase shift window width, an opaque field overlying a region of phase transition along the respective first sides in between the first and second phase shift windows, the opaque field having a control width, the trim mask pattern including an opaque trim shape in location corresponding with said region of phase transition and having a trim width in the dimension parallel with said control width; the method comprising: applying an adjustment to at least one of the phase shift mask pattern and a trim mask pattern based upon one or both of a rule based correction and a model based correction to improve a match between a resulting exposure pattern and said target feature, said adjustment including more than one of: (1) adjusting said first phase shift window width and said second phase shift window width, (2) adjusting said control width, (3) adjusting said trim width, (4) adding a sub-resolution opaque shape to one or both of the first and second phase shift windows, (5) adding a clear shape to the trim shape, and (6) adding one or more opaque shapes to one or both of the first and second phase shift windows and adding a clear shape or shapes to the trim.