| abstract |
A high data-rate spot-grid array imaging system includes a periodic array of lenses, each lens imaging a spot in an object plane, such as a semiconductor substrate to be inspected, upon an image plane to image a periodic array of spots. A sensor is provided in a conjugate image plane with a periodic array of readout elements, each collecting the signal from one of the spots. A mechanical system moves the substrate in a direction which is nearly parallel to an axis of the arrary of spots such that as the substrate is moved across the spot array in the scan direction (the y-direction) the spots traces a path which leaves no gaps in the mechanical cross-scan direction (the x-direction). A compensator, such as a servo or a movable mirror, compensates for mechanical inaccuracies in the moving stage, thereby increasing imaging accuracy. |