A double shift self-calibration method for micro XY stages

In most cases calibration of measuring instruments is obtained by comparing measurement results to a measurement standard. But in the case of coordinate measuring system, the availability of reliable measurement standards is often limited: calibrated ball plated, for example, are expensive and difficult to maintain. This originated the so called “self-calibration” procedures, in which an uncalibrated artifact is adopted to estimate the stage error of the system. One of the most widespread coordinate measuring systems is an stage. Several procedures have been proposed for the self-calibration of this kind of system. Most of them are based on performing three or more measurements of an uncalibrated plate, with the position of the plate changing from one measurement to the other. Oftentimes, the positions are only slightly different from each other, thus making it difficult to obtain them with a good accuracy when measurements are carried out at a micro scale. In this work, an approach is proposed which allows larger displacement from one measurement to the others, thereby allowing an easier management for micro stages.