Patent ID: 6127075
Filing Date: 2000-10-03
Classification: G03F

Abstract:
A method for checking accuracy of a measuring instrument for overlay registration, comprising the steps of:simultaneously forming a set of overlay marks on a calibration mask, said overlay marks including an outer box and an inner box, the outer box being larger than the inner box, wherein the outer and inner boxes having the same central point;coating a photoresist layer atop a control wafer;exposing the photoresist layer through the mask and then developing the photoresist layer so as to transfer the set of overlay marks to the photoresist layer atop the control wafer; andusing an instrument to measure a shift amount of the central point of the outer box relative to the central point of the inner box on the control wafer, said instrument being an overlay registration measuring instrument,wherein the shift amount represents a degree of inaccuracy of the overlay registration measuring instrument.