Integrated reflectometer or ellipsometer

Abstract

A reflectometer or ellipsometer integrated with a processing tool includes a source module configured to generate a input beam, and a first mirror arranged to receive the input beam. The first mirror is configured to collimate the input beam and direct the input beam toward an aperture plate. The aperture plate has at least two apertures. One of the at least two apertures is arranged to define a measurement beam from a portion of the input beam, and one of the at least two apertures is arranged to define a reference beam from a portion of the input beam. An optical element is arranged within an optical path of the reference beam and outside an optical path of the measurement beam. The optical element is configured to direct the reference beam toward a third mirror. A second mirror is arranged to receive the measurement beam and focus the measurement beam through a window and onto a surface of a sample. The window forms part of a chamber of the processing tool and the sample is disposed within the chamber. At least a portion of the measurement beam is reflected from the surface of the sample as a reflected beam. The second mirror is arranged to receive the reflected beam and direct the reflected beam toward the optical element. The optical element is configured to direct the reflected beam toward the third mirror. The third mirror is arranged to receive the reference beam and the reflected beam and focus the reference beam and the reflected beam onto a collection plane.

Description

[0001] Cross References to Related Applications [0002] This application claims the benefit of U.S. nonprovisional application Ser. No. 16 / 672,233, filed November 1, 2019, which is hereby incorporated by reference in its entirety for all purposes. technical field [0003] Embodiments described herein relate generally to reflectometers or ellipsometers, and more particularly to compact reflectometers or ellipsometers integrated with processing tools. Background technique [0004] Semiconductor manufacturing process control requires accurate measurement of film thickness and pattern critical dimension (CD). Spectral reflectometers or ellipsometers have been used for film thickness and pattern CD measurements to provide feedback for process diagnostics and control. Integrating film thickness and pattern CD measurement systems with processing tools is desirable as this reduces time to results and enables measurements that cannot be performed using stand-alone tools. For examp...

AI Technical Summary

Problems solved by technology

The measurement window in the vacuum chamber must be thick enough to cover a large area, and this tends to degrade the spot quality and limit the working distance

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