WAFER ALIGNING METHOD USING DOUBLE WAVELENGTH LASER

摘要

PURPOSE: A wafer aligning method using a double wavelength laser is provided to be capable of improving the overlay state between layers. CONSTITUTION: A double wavelength He-Ne laser light source is incident. A plurality of wafer align marks having a constant pitch, are formed at the upper portion of a wafer according to the incident light source. When the incident light source is reflected from the wafer align marks, the quantities of light for the first ±1 and ±2 order diffraction beams corresponding to the first wavelength of the light source and the second ±1 and ±2 order diffraction beams corresponding to the second wavelength, are detected by using a detector(30) installed at the inner portion of an alignment apparatus. At this time, the quantities of light for the first ±1 and ±2 order diffraction beams corresponding to the first and second wavelength, are simultaneously detected for improving precision and reliability.