Application of the photocleave technique in sub-micron contact window lithography

Application of the photocleave technique in stepper-based lithography for nondestructively examining the size and shape of submicron contact windows defined in photoresist during VLSI (very-large-scale integration) processing is described. It involves double exposures into photoresist on a sample wafer so that a special linear feature sections the latent image of contact windows. After development, the uncoated photocleaved windows in photoresist can be examined with high signal-to-noise ratio by quick-turnaround low-voltage SEM (scanning electron microscopy). The sample wafer is then reworked and rejoins the lot