METHODS AND APPARATUS FOR MEASURING HEIGHT ON A SEMICONDUCTOR WAFER

摘要

Disclosed are apparatus and methods for determining height of a semiconductor structure. The system includes an illumination module for directing one or more source lines or points towards a specimen having multiple surfaces at different relative heights and a collection module for detecting light reflected from the surfaces. The collection module contains at least two detectors with one slit or pinhole in front of each detector that that are positioned to receive light reflected from one of the surfaces. A first detector receives reflected light from a slit or pinhole that is positioned before a focal point, and a second detector receive reflected light from a slit or pinhole that is positioned after the focal point so that the first and second detector receive light having different intensity values unless the surface is at an optimum focus. The system includes a processor system for determining a height based on the detected light received by the detectors from two of the surfaces.

主权项

1. A system for determining height of a semiconductor structure, comprising:
an illumination module for directing one or more source lines or points towards a specimen having a plurality of surfaces at different relative heights; a collection module for detecting light reflected from the surfaces, wherein the collection module contains at least two detectors that are positioned to receive light reflected from a one of the surfaces, wherein a first one of the detectors receives more reflected light from a position before a focal point and a second one of the detectors receives more reflected light from a position after the focal point so that the first and second detector receive light having different intensity values unless such one of the surfaces is at an optimum focus; and a processor system for determining a height based on the detected light received by the at least two detectors from two of the surfaces.