State-of-the-art electronic structure calculations yield results consistent with the observed compound SiLi2Mg and provide likelihood of the availability of IrLi2Mg and RhLi2Mg. The frames are pre-processed to extract envelope curves and their corner shape features. With the dummy patterns formed in the pattern-interspersed region at the intervals as described above, when one scan target range is scanned by the mask pattern defect inspecting apparatus, at least one dummy pattern is included in the scan target range in the pattern-interspersed region.