Pattern Acquisition Technology for Semiconductor Navigation System

A semiconductor navigation system based on Scanning Electron Microscope has been developed to fast locate the smallest defects which can bring wafer production to a waster. The mainly parts of the navigation system are pattern acquisition model and scanning model. The pattern acquisition model is made up of an Analog-to-Digital Convertor, a CPLD and a Static RAM. The electron-beam is controlled by scanning model to scan the wafer. In the same time, the pattern acquisition model gathers the secondary electrons reflected by wafer and converts them to gray value. Those gray values of each point in scanning field are transmitted to computer through USB2.0 interface, and assembled to a whole pattern of wafer production according to the "lattice principle" by succeeding software. Legible wafer pattern is obtained by using this system.