| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an efficient OPC method of increasing imaging performance of a lithographic process utilized to image a target design having a plurality of features. <P>SOLUTION: The method includes steps for: determining a function for generating a simulated image, where the function accounts for process variations associated with the lithographic process; and optimizing a target gray level for each evaluation point in each OPC iteration based on this function. In one given embodiment, the function is approximated as a polynomial function of focus and exposure, R(ε, f)=P<SB>0</SB>+f<SP>2</SP>P<SB>b</SB>with a threshold of T+Vε for contours, where P<SB>0</SB>represents image intensity at a nominal focus, f represents a defocus value relative to the nominal focus, ε represents the exposure change, V represents the scaling of the exposure change, and parameter P<SB>b</SB>represents second order derivative images. In another given embodiment, an analytical optimal gray level is given for the best focus with the assumption that the probability distribution of focus and exposure variation is Gaussian. <P>COPYRIGHT: (C)2010,JPO&INPIT |
