OVERLAY VERNIER AND METHOD OF MAKING THE SAME

摘要

PURPOSE: A method for fabricating an overlay vernier is provided to control an overlay, by reducing errors in reading the overlay and by decreasing an overlay burden in a high density ion implantation process as an integration degree becomes higher. CONSTITUTION: A chrome layer is formed on a quartz substrate. The chrome layer is selectively patterned to form a light blocking layer(22a) of a square ring type. A predetermined width and depth of the quartz substrate between the light blocking layers is etched to form a trench of a square box type. A shifter layer(27) filled in the trench is formed.