Abstract: A method for optimizing a measurement pattern of measurement points for a semiconductor wafer includes (i) obtaining a plurality of measured values with associated measurement points and timestamps, (ii) partitioning the semiconductor wafer into zones, wherein the zones are characterized in that measured values whose measurement positions are within the respective zone have the same characteristic, (iii) determining a variation of the measured values for each of the zones along a predetermined time period, the timestamps of which are within the predetermined time window, and (iv) defining the measurement pattern, wherein, depending on the variations, a measurement point density is defined for each of the zones, in particular a higher measurement point density is selected in the zones with higher variation along the time.

Abstract: For the correction of measurement errors, due to vibration, of coordinate measuring devices, the time course of the interfering vibrations is stored by means of sensors (a.sub.x, a.sub.y, a.sub.z) on a vibrating portion of the coordinate measuring device. The measured values of the sensors are adjusted with previously determined and stored correction parameters, which describe the natural frequency (.nu.) and the damping constants (.delta.) of the vibrations and also the amplitude and phase information of the characteristic modes (G.sub.r) of the vibrations contributing to the interfering vibrations. The measurement errors, due to vibration, of the coordinate measuring device at the instant of probing are then calculated from the time course of the corrected measurement values of the sensors (a.sub.x, a.sub.y, a.sub.z).

Abstract: A computer-operated coordinate-measurement machine has two length-measurement systems arranged in parallel for measuring the longitudinal displacement of a probe carried by the portal (3-5) of the machine, and these two length-measurement systems (13, 14) may belong to different precision classes. A computer-associated device (16) forms an absolute position-measurement value (Ym) from length-measurement signals of the more precise measurement system (13) and said device forms a dynamic measurement or instantaneous deviation value (Ys-Ym) from the difference between length-measurement signals of the respective systems (13, 14). The computer of the machine calculates the effective instantaneous position (Ym+.DELTA.y) of the probe (9a, b, c) borne by the portal (3-5), using the instantaneous value of the transverse position of the probe on the portal, in conjunction with the absolute measurement value (Ym) and the dynamic measurement value (Ys-Ym).