Multiple angles of incidence semiconductor metrology systems and methods

摘要

An apparatus includes (i) a bright light source for providing an illumination beam at multiple wavelengths selectable with a range from a deep ultraviolet wavelength to an infrared wavelength, (ii) illumination optics for directing the illumination beam towards a sample at selectable sets of angles of incidence (AOI's) or azimuth angles (AZ's) and polarization states to provide spectroscopic ellipsometry, wherein the illumination optics include an apodizer for controlling a spot size of the illumination beam on the sample at each of the selectable AOI/AZ sets, (iii) collection optics for directing an output beam from the sample in response to the illumination beam at each of the selectable AOI/AZ sets and polarization states towards a detector that generates an output signal or image based on the output beam, and (v) a controller for characterizing a feature of the sample based on the output signal or image.

主权项

1. An ellipsometer apparatus for performing metrology of a semiconductor sample, comprising:
an illumination optics module for providing an illumination beam at a plurality of wavelengths that are selectable within a range from a vacuum ultraviolet (VUV) wavelength to an infrared (IR) wavelength and directing the illumination beam towards the sample at a plurality of angles of incidence (AOI's) and/or azimuth angles (AZ's), wherein the illumination optics comprises:
a first off axis parabolic (OAP) mirror,a first translation mirror that is movable to receive the illumination beam at a plurality of positions to direct the illumination beam to a plurality of positions on the first OAP mirror so that the first OAP reflects the illumination beam to the sample at the discrete ranges of AOI and/or AZ one at a time, andpolarization generating optical elements for generating a plurality of polarization states for the illumination beam; a collection optics module for collecting an output beam emanating from the sample at a plurality of discrete ranges of AOI and/or AZ and directing such output beam to a detector module, wherein the discrete ranges are collected one at a time and the output beam being in response to the illumination beam on the sample, wherein the collection optics module comprises:
a detector,a second OAP,a second translation mirror that is movable to receive the output beam at a plurality of positions to direct the output beam to a plurality of positions on the second OAP mirror so that the second OAP reflects the output beam at the discrete ranges of AOI and/or AZ to the detector one at a time, andpolarization analyzing optical elements for analyzing the polarization state of the output beam; the detection module for receiving and detecting the output beam from the sample at the discrete ranges of AOI and/or AZ and the polarization states and generating a plurality of signals based on the output beam at the discrete ranges of AOI and/or AZ and the polarization states; and one or more controllers that are each configured to control one or more of the following: selecting a wavelength range, selecting one or more of the discrete ranges of AOI and/or AZ for collection of the output beam, selecting the polarization states, and analyzing the signals at the discrete ranges of AOI and/or AZ and the polarization states to determine a characteristic of the sample, wherein the illumination optics module and the collections optics modules comprises reflective optical elements between the polarization generation optical elements and the polarization analyzing optical elements.