Patent ID: 8679708
Filing Date: 2014-03-25
Classification: G01J,G03F,G06F

Abstract:
1. A method of designing a phase-shifting region in a mask for lithographic scanners comprising: providing a design of a phase shifting region of a mask, the mask having adjacent 0°, 90°, 180° or 270° phase shifting regions of relative widths corresponding to the relative widths of phase shifted regions of light to be projected through the reticle onto a photoresist layer, the phase shifting regions being separated by vertical boundaries in the mask; determining an average bias distance X needed to move the vertical boundaries in the mask between regions of 90° phase difference to create a desired width of phase shifted light on the photoresist layer; biasing the design by moving each boundary between phase shifted regions toward the lower phase region by a distance D: wherein PD is the difference in phase between phase shifting regions on either side of the boundary; and creating a mask having the biased design of the phase shifting regions.