Multiexposure spatial frequency multiplication is a technique that allows the spatial frequency of grating patterns to be increased by integer factors 2,3,4,... by applying a nonlinear development process between patterning steps. One of the main technical issues with this technique is how to accurately place subsequent patterns on a substrate with respect to previously established patterns, which is referred to as phase control of the overlay. The authors report a technique that achieves accurate phase control over large areas during spatial frequency multiplication by utilizing a surrounding alignment grating. Three key factors-the angle, period, and phase of the alignment grating-have been accurately measured and utilized to position subsequent patterns with respect to previous patterns. Some factors that can dramatically diminish the accuracy of phase control, such as particle-induced substrate distortion and nonlinear distortion of the alignment grating, have also been considered and minimized in order to improve the accuracy of phase control. For spatial frequency doubling with a 574 nm principal pitch, the authors achieved overlay phase errors with a mean of -1.0 nm +/- 2.8 nm(1 sigma) between level 1 and level 2 grating patterns over a 25 x 32.5 mm(2) area. (C) 2007 American Vacuum Society.