METHOD OF MEASURING DEPTH OF TRENCH IN SEMICONDUCTOR SUBSTRATE WITHOUT CONTAMINATION AND DAMAGE OF SEMICONDUCTOR SUBSTRATE

摘要

PURPOSE: A method of measuring the depth of a trench in a semiconductor substrate is provided to prevent the substrate from being contaminated and scratched due to a metallic probe of a conventional alpha-step manner by using optical processing. CONSTITUTION: First and second laser beams are irradiated on a wafer(10) with a trench, wherein the first and second laser beams have a predetermined incident angle(&thgr;) on the wafer. A first reflected laser point(50') of the first laser beam and a second reflected laser point(60') of the second laser beam are detected by a sensor(40). A distance(a) between the first and second reflected laser points is measured. A depth of the trench is calculated according to the measured distance and the predetermined incident angle of each laser beam.