An apparatus for measuring the focus of a light exposure system for selectively exposing a photosensitive plate to light rays in a process of fabricating a semiconductor device, wherein there is provided a focus measuring part having opaque region, transparent region, and a transparent electrode arranged in the transparent region, a conducting stage supporting the photosensitive plate; and a capacitance detector for measuring the capacitance between the transparent electrode and the conducting stage.

A method for verifying scan precision of a laser measurement machine includes the steps of: preparing a transparent flat, of which the flatness of each plane is regarded as a flatness conventional true value; determining an optimum scanning mode; determining optimum scanning parameters under the optimum scanning mode; scanning the transparent flat under the optimum scanning mode and the optimum scanning parameters for certain times, and obtaining measuring data; calculating a plurality of flatness values using the measuring data; calculating an average value and a standard deviation of the flatness values, and a bias between the average value and the flatness conventional true value; evaluating the repetitiveness of the laser measurement machine according to the standard deviation; and evaluating the veracity of the laser measurement machine according to the bias.

A method of measuring warpage of a rear surface of a substrate includes a substrate detection step, a best fit plane calculation step, and a warpage calculation step. Further, the method of measuring warpage of a rear surface of a substrate can further includes after the substrate detection step and before the best fit plane calculation step: a noise removal step and an outer peripheral portion removal step; the outer peripheral portion removal step and a smoothing step; or the noise removal step, the outer peripheral portion removal step, and the smoothing step. Thereby, a method of measuring warpage of a rear surface with a high surface roughness of a substrate can be provided.

An exposure system having an exposure apparatus for transferring a pattern of a first object onto a second object, which includes an exposure apparatus having a detecting system for performing relative alignment of the first object and the second object, a transmitting system for transmitting, to a remote location and through a public data line, a mark detection signal obtained by detection of a mark of the second object made by use of the detecting system and shape information obtained by measurement of a shape of the mark on the second object, and a calculating system for performing calculation of an offset of the exposure apparatus, at the remote location. The calculating system transmits information, including the offset, to the exposure apparatus and through the public data line, and, on the basis of the information including the offset, alignment of the first and second objects is executed by using the detecting system and an exposure process is performed in the exposure apparatus.

Apparatus for measuring the surface profile of a sample, includes a fixture for locating a surface of a transparent optical flat relative to a surface of a sample; a low-coherence light interferometer having an optical probe coupled to an XY scanning frame for scanning the surface of the sample through the transparent optical flat to produce interferometric data signals representing the distances between the optical flat surface and the surface of the sample; and a computer system responsive to the interferometric data signals for generating a surface profile of the sample using a best fit to a plane.