Patent ID: 7937676

Claim:
A method of arranging mask patterns on a semiconductor wafer, the method comprising: deriving in a first process an h-function which represents a contribution of an assist feature with respect to image intensity at a main feature; determining in a second process a position of the assist feature using the h-function; and arranging a mask pattern on the semiconductor wafer, using a computer system, according to the determining step, wherein the h-function is determined by: I ⁡ ( x ) - I 0 ⁡ ( x ) 2 ⁢ I 0 ⁡ ( x ) = h ⁡ ( ξ - x ) ⁢ ⁢ m ⁡ ( ξ ) ⁢ ⁢ Δξ , where x indicates the position of the main feature, ξ indicates the position of the assist feature, I(x) indicates image intensity at the main feature when the assist feature exists, l o (x) indicates image intensity at the main feature when the assist feature does not exist, and m(ξ) indicates transmittance of a mask, wherein the method further comprises deriving in the first process the h-function for each of a plurality of main features arranged at different positions on the mask, and wherein the method further comprises determining in the second process the position of the assist feature from a set of ξ values which makes the value satisfying ∑ x ∈ M ⁢ h ⁡ ( ξ - x ) equal to or greater than a predetermined threshold value, where M indicates the entire domain of the mask.