SYSTEM FOR ALIGNING WAFERS AND FOR READING MICRO BAR-CODES AND MARKS ON CHIPS USING LASER

摘要

The invention relates to a system for reading micra-sized marks on semiconductor wafers, which can be connected to wafer measurement test stations. The aforementioned micra-sized marks can be bar-codes containing information or special marks for the alignment of the axes of the chips on the wafer in relation to the axes of movement X and Y of the station. The invention consists of a laser reading system of the type used in CD players, which enables micrometer resolution. The reading system is stationary while the wafer moves by means of motors in the test station. The advantages of the invention lie in the simplicity of the system which can be connected to any existing test station and which is, therefore, very cheap. In addition, said system can be used to read micro bar-codes containing the relevant information of each chip.