Abstract: An apparatus and method are disclosed for improving the recognition of reference data in a laser writing process, by storing the locations of chip topography situated along the scan raster in a memory. Using an entry code (reference mark) to provide synchronization of the laser beam and the chip topography, the digital signal coming from the detector of the scanning laser beam is checked for accuracy against the stored pattern. A synchronous correlator circuit is used to provide a corrected output based on the stored information and the actual detected signal which is then used to control the operation of the laser pattern generator. Incorrect tracking of the laser pattern generator due to defects in the scanned surface can thus be reduced or eliminated. Due to this improved recognition of surface reference points, smaller geometries can be used.

Abstract: There is disclosed a semiconductor chip and a method of directing a first writing laser beam and a second scanning laser beam across the surface of the semiconductor chip. The semiconductor chip includes first and second edges and a recognition pattern to be scanned by the scanning laser beam to facilitate the control of the relative movement of the semiconductor chip and the writing laser beam. The recognition pattern includes a pair of first enter codes disposed respectively along the first and second edges. Each of the first enter codes includes a synchronization mark and a step recognition mark disposed behind the synchronization mark considering that the scanning laser beam is directed from its edge to first scan the synchronization mark and then the step recognition mark.