| 摘要 |
A mask pattern obtained by a dipole aperture illumination system is provided to prevent merging in photoresist by reducing the size of a mask pattern in the direction of dipole aperture arrangement and widening the space between the mask patterns, and thus to reduce or minimize faults in overlay measurement. The overlay mask pattern obtained by dipole aperture illumination comprises a plurality of dot type patterns(110) with a certain size and space, which are periodically formed on a wafer, wherein the space between the dot type patterns is at least 0.4 micrometers or more in the direction of dipole aperture arrangement.
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