This invention relates to subterranean treatment operations. The pattern inspection apparatus is equipped with an image comparing section which plots individual pixels of an inspection subject image in a feature space and detects excessively deviated points in the feature space as defects. By means of the series circuit, individual semiconductor memory chips can be driven selectively with respect to the rest of the semiconductor memory chips without having to interrupt the regular data transport via the address and control lines. The created test package is provided to a computer machine.