| 摘要 |
Techniques are provided for extending the use of phase shift techniques to implementation of masks used for complex layouts in the layers of integrated circuits, beyond selected critical dimension features such as transistor gates to which such structures have been limited in the past. The method includes identifying features for which phase shifting can be applied, automatically mapping the phase shifting regions for implementation of such features, resolving phase conflicts which might occur according to a given design rule, and application of sub-resolution assist features within phase shift regions and optical proximity correction features to phase shift regions. In one approach, phase shift regions are laid out so that they extend around corners in a feature, and in one or more identified corners having greater process latitude, the phase shift regions are divided and assigned opposite phases in the corner. In another approach, phase shift regions are laid out so that they do not extend through the corners, and then phase shift regions are merged in all but the identified corners. Both opaque field phase shift masks and complementary binary masks defining interconnect structures and other types of structures that are not defined using phase shifting, necessary for completion of the layout of the layer are produced.
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