Therma-wave, Inc.

Kla-tencor Technologies Corporation

Louis N Koppel

Craig E Uhrich

Jon Opsal

Jeffrey Thomas Fanton

William Johnson

Charles Schmelz

In the calibration and alignment of an X-ray reflectometry ('XRR') system for measuring thin films, an approach is presented for accurately determining Cfor each sample placement and for finding the incident X-ray intensity corresponding to each pixel of a detector array and thus permitting an amplitude calibration of the reflectometer system. Another approach involves aligning an angle-resolved X-ray reflectometer using a focusing optic, such as a Johansson crystal. Another approach relates to validating the focusing optic. Another approach relates to the alignment of the focusing optic with the X-ray source. Another approach concerns the correction of measurements errors caused by the tilt or slope of the sample. Yet another approach concerns the calibration of the vertical position of the sample.

Calibration and alignment of X-ray reflectometric systems

A detector assembly is introduced that provides shielding of irradiation vulnerable regions of an X-ray detector against directly impinging and scattered X-rays. A shielding unit has a primary aperture to shape an X-ray beam reflected from a test area of a work piece such that the shaped beam directly impinges an X-ray sensing area of the detector. A secondary aperture shields off X-rays scattering off along the edges of the primary aperture. In the preferred embodiment, the shielding unit is a monolithic structure. An area between primary and secondary aperture is laterally recessed to prevent a portion of scattered X-rays from being deflected onto the sensing area.

Detector-shield assembly for X-ray reflectometric system

The present invention relates to the calibration and alignment of an X-ray reflectometry (&ldquo;XRR&rdquo;) system for measuring thin films. An aspect of the present invention describes a method for accurately determining C for each sample placement and for finding the incident X-ray intensity corresponding to each pixel of a detector array and thus permitting an amplitude calibration of the reflectometer system. Another aspect of the present invention relates to a method for aligning an angle-resolved X-ray reflectometer that uses a focusing optic, which may preferably be a Johansson crystal. Another aspect of the present invention is to validate the focusing optic. Another aspect of the present invention relates to the alignment of the focusing optic with the X-ray source. Another aspect of the present invention concerns the correction of measurements errors caused by the tilt or slope of the sample. Yet another aspect of the present invention concerns the calibration of the vertical position of the sample.

An x-ray reflectometry system for measuring thin film samples. The system includes an adjustable x-ray source, such that characteristics of an x-ray probe beam output by the x-ray source can be adjusted to improve the resolution of the measurement system. The x-ray probe beam can also be modified to increase the speed of evaluating the thin film sample, for situations where some degree of resolution can be sacrificed. In addition, or alternatively, the system can also provide an adjustable detector position device which allows the position of the detector to be adjusted to increase the resolution of the system, or to reduce the time it takes to evaluate the thin film material.

X-ray reflectance measurement system with adjustable resolution

A metrology system and method for measuring the thickness of thin-films of semiconductor wafer. This system and method analyze x-ray reflectivity data to determine transmission characteristics of thin-film layers. Based on these transmission characteristics the thickness of the thin-layer can be determined. Unlike some prior systems and methods, the system and method herein does not determine the thickness of the thin-film layer based on a fringe pattern in reflectivity for the thin-film layer. The fact that the system and method herein does not rely the fringe pattern is particularly advantageous in situations where the thin-film layer is of thickness which makes it very difficult to resolve the fringe pattern in the reflectivity data.

Growing community of inventors

Menlo Park, CA, United States of America

Louis N Koppel