Apparatus for measuring depth and gradient of trench in semiconductor device and method thereof

Abstract

An apparatus for measuring a depth and a gradient of a trench in a semiconductor device including: a light emitting element for making a light incident on a wafer while varying an incident angle, the wafer having a trench structure carried by a test sample carrying unit; a detect unit for detecting a light reflected from the wafer at a position symmetrical to the light emitting element on the basis of a virtual vertical line perpendicular to the wafer; a photoelectric conversion unit for converting an intensity of a light detected by the detect unit to an electric signal; an operating unit for receiving an output signal from the photoelectric conversion unit, catching a time point where the size of the received signal is increased or maintained, computing a depth of the trench by using a critical angle, that is, an incident angle where the incident light is reflected from the central portion of a lower surface of the trench, and judging the time point when the increasing output signal of the photoelectric conversion unit is maintained when the incident angle is below a critical angle as a sloping angle of the trench; and a display unit for displaying an operating result of the operating unit. By having such a construction, the gradient of the trench as well as the depth can be easily obtained by using the wafer where the semiconductor device is to be formed, without additionally making a test sample for measurement, so that a production cost can be much reduced and a reliability of the semiconductor device is much improved.

Dependencies are inferred from the claim text.