N K Technology Ltd

Nsh Technology, Inc.

Abdul Rahim Forouhi

Guoguang Li

Dale A Harrison

Michael J Mandella

Marc T Aho

Phillip Walsh

Mehdi Balooch

Weilu Hang Xu

Hongwei Zhu

Shuqiang Chen

Ray Hebert

John C Lam

Jeff Roberts

Erik Nackerud

Homan Amin

Erik Maiken

Eric Maiken

The refractive index, extinction coefficient, size and density of fluid suspended particles are simultaneously determined by combined transmittance and scattering measurements. The scattering measurements are preferably angle selective to obtain additional information about the scattered light. A charge-coupled device is employed for its high sensitivity to low light intensity in measurement of scattered light in combination with a photodiode array employed for its high signal to noise ratio, which is beneficial in transmittance measurement. The scattered light may be measured in an angle selective fashion by use of a motorized aperture that is concentrically positioned with respect to the impinging beam axis and moveable along the impinging beam axis. An ellipsoidal mirror collects the scattered light that passes through the motorized aperture and focuses the scattered light towards the charge-coupled device.

Combined transmittance and angle selective scattering measurement of fluid suspended particles for simultaneous determination of refractive index, extinction coefficient, particle size and particle density

This invention relates to an apparatus and method for integrated measurement of a sample that has miniature features. The apparatus has an optical measuring unit for illuminating the sample with a global test radiation over an optical test region and obtaining an optical response, such as scattered or transmitted radiation from the optical test region. In addition, the apparatus has a local measuring unit for making a nanometer scale measurement of a local material parameter &#x3c1; of the sample. The local parameter &#x3c1; is determined with a mechanical, optical, magnetic, electric or other physical measurement performed in the nanometer range with a scanning probe tip at a test location lying within the optical test region. The material parameter &#x3c1; is selected such that it is substantially constant or uniform over the illuminated area. A computational unit determines a property of the miniature features within the optical test region from the optical response supplemented with an adjustment derived from the local material parameter obtained by the local measuring unit.

Integrated local and global optical metrology for samples having miniature features

An apparatus and method for examining features of a sample with a broadband beam of light obtained from a long-wavelength source that may include two distinct emitters that emit a long-wavelength radiation and a short-wavelength source that emits a short-wavelength radiation. A passage is positioned between the sources and a reflective beam combining optics is provided for shaping the long-wavelength radiation to enter the short-wavelength source via the passage and also for shaping the short-wavelength radiation that exits through the passage and propagates toward the long-wavelength source. The reflective beam combining optics shape the short-wavelength radiation such that it re-enters the short-wavelength source via the passage and is combined with the long-wavelength radiation into the broadband beam that exits the short-wavelength source. A beam steering optics projects the broadband beam to a spot on the sample, and a scattered broadband radiation from the spot is intercepted and shaped to a broadband signal beam, which is passed through a sampling pinhole that passes a test portion of it on to a detector for optical examination; the test portion that is passed can correspond to a center portion of the spot.

System and method for high intensity small spot optical metrology

A system uses reflectance spectrophotometry to characterize a sample having any number of structures. The system uses toroidal mirrors that are shaped in such a way that the angle of reflectance off of the target is small. The small angle of reflectance may allow for simplification of calculations and can result in a faster processing time. In addition, a more accurate measurement can be achieved when the reflected beam is close to normal.

Spectrophotometric system with reduced angle of incidence

An apparatus and method for optically characterizing the reflection and transmission properties of a sample with a beam of light having a small diameter on a surface of the sample over a broadband of wavelengths, from 190 nm to 1100 nm. Reflective optical components, including off-axis parabolic mirrors with a collimated incident or reflected broadband beam of light, minimize non-chromatic aberration. Angles of incidence and reflection from optical components and the sample are kept substantially near normal to the optical components and the sample to minimize changes in the polarization of the beam of light. The apparatus and method further disclose an optical light path that can be focused by adjusting the position of an off-axis parabolic mirror and a planar mirror.

Apparatus and method for optical characterization of a sample over a broadband of wavelengths while minimizing polarization changes

A system and method for optical offset measurement is provided. An offset between two grating layers in a compound grating is measured by illuminating the gratings with light having a plane of incidence that is neither parallel with nor perpendicular to the grating lines. This non-symmetrical optical illumination allows determination of the sign and magnitude of the offset. Two measurements are performed at azimuthal angles separated by 180&#xb0;, and a difference of these measurements is calculated. Measurement of this difference allows determination of the offset (e.g., with a calibration curve). Alternatively, two compound gratings having a predetermined non-zero offset difference can be employed. This arrangement permits determination of the offsets without the need for a calibration curve (or for additional compound gratings), based on a linear approximation.

System and method for measuring overlay alignment using diffraction gratings

An apparatus and method for determining a physical parameter of features on a substrate by illuminating the substrate with an incident light covering an incident wavelength range &#x394;&#x3bb;, e.g., from 190 nm to 1000 nm, where the substrate is at least semi-transparent. A response light received from the substrate and the feature is measured to obtain a response spectrum of the response light. Further, a complex-valued response due to the feature and the substrate is computed and both the response spectrum and the complex-valued response are used in determining the physical parameter. A direct approximate phase measurement is provided when the response light is transmitted light.

Phase shift measurement using transmittance spectra

An apparatus and method for optically characterizing the reflection and transmission properties of a sample with a beam of light having a small diameter on a surface of the sample over a broadband of wavelengths, from 190 nm to 1100 nm. Reflective optical components, including off-axis parabolic mirrors with a collimated incident or reflected broadband beam of light, minimize non-chromatic aberration. The apparatus and method further disclose an optical light path that can be focused by adjusting the position of an off-axis parabolic mirror and a planar mirror.

Apparatus and method for optical characterization of a sample over a broadband of wavelengths with a small spot size

An apparatus and method for determining a physical parameter of features on a substrate by illuminating the substrate with an incident light covering an incident wavelength range &#x394;&#x3bb;, e.g., from 190 nm to 1000 nm, where the substrate is at least semi-transparent. A response light received from the substrate and the feature is measured to obtain a response spectrum of the response light. Further, a complex-valued response due to the feature and the substrate is computed and both the response spectrum and the complex-valued response are used in determining the physical parameter. The response light is reflected light, transmitted light or a combination of the two. The complex-valued response typically includes a complex reflectance amplitude, a complex transmittance amplitude or both. The apparatus and method take into account the effects of vertical and lateral coherence length and are well suited for examining adjacent features.

Method and apparatus for examining features on semi-transparent and transparent substrates

Embodied in a reflectance system capable of providing high resolution, repeatable, efficient, and accurate reflectance measurements of a silicon or silicon-oxide wafer at all wavelengths, the present invention, including an inventive and useful software tool with user interface, provides a solution to monitor non-destructively low dose ion implantation without potentially suffering from undesirable annealing effect. The computer-implemented method disclosed herein determines a reflectance change index that correlates to the ion dose. The reflectance change index is determined based on an absolute value of reflectance changes over the entire measured spectra. The reflectance changes are determined based on non-implanted and implanted reflectance measurements of the wafer respectively obtained at each of the wavelengths.

Computer-implemented reflectance system and method for non-destructive low dose ion implantation monitoring

The present invention provides a method for inferring optical parameters of a sample in a predictive spectral range by use of the known values of the optical parameters in a predetermined measurement spectral range. The method of the present invention capitalizes on the Forouhi-Bloomer dispersion equations for the optical constants n and k.

Method of inferring optical parameters outside of a measurement spectral range

The present invention provides a method for monitoring a modifying-process taking place in a thin-film sample and thereby characterizing the sample thus modified, wherein the modifying-process is performed for purpose of improving physical properties of the sample. The present invention further provides a monitoring tool for characterizing various thin-film processes. Advantages of the method of the present invention are manifest in its non-intrusive nature, fast (or real-time) response, robust sensitivity, and versatility in a variety of thin-film processes. Another inherent advantage of the present invention is that an assortment of the &ldquo;n&k&rdquo; parameters can be obtained by using only measurement tool, in contrast to two (or more) simultaneous measurement tools used in the prior art.

Method of monitoring thin-film processes and metrology tool thereof

A method and an apparatus for optically determining a physical parameter such as thickness t, index of refraction n, extinction coefficient k or a related physical parameter such as energy bandgap E of a thin film. A test beam having a wavelength range &Dgr;&lgr; is used to illuminate the thin film after it is deposited on a complex substrate which has at least two layers and exhibits a non-monotonic and an appreciably variable substrate optical response over wavelength range &Dgr;&lgr;. Alternatively, the thin film can be deposited between the at least two layers of the complex substrate. A measurement of a total optical response, consisting of the substrate optical response and an optical response difference due to the thin film is performed over wavelength range &Dgr;&lgr;. The at least two layers making up the complex substrate are chosen such that the effect of multiple internal reflections in the complex substrate and the film is maximized. The physical parameters are determined from the total optical response which can be in the form of a reflected and/or a transmitted beam.

Method and apparatus for optically determining physical parameters of thin films deposited on a complex substrate

A graded anti-reflective coating (ARC) with one or more layers has a bottom layer that is highly absorbing at the lithographic wavelength, and one or more layers between the substrate and the resist layer having inhomogeneous optical constants. The refractive indices are matched across layer interfaces, and the optical constants vary smoothly through the layer thicknesses. In each layer the extinction coefficient and the refractive index have independently selectable values and gradients. This ARC structure provides almost total absorption in the bottom layer and near-zero reflection at the resist interface and all other intermediate interfaces. Layers are preferably of inorganic materials, typically SiO N . Because of its highly absorbing bottom layer, an ARC according to an embodiment of the present invention works effectively over diverse substrate materials for a variety of lithographic wavelengths. It provides great latitude of manufacturing tolerances for thicknesses and optical constants.

Graded anti-reflective coatings for photolithography

A method and apparatus for optically determining a physical parameter a pattern made up of features and disposed on an underlayer. The physical parameter can be, e.g., feature width, relative feature size, feature thickness, index of refraction n or extinction coefficient k and is determined from a response light generated upon illumination of the pattern and underlayer. The response light, e.g. light transmitted by or reflected from the pattern and from the underlayer is analyzed and broken down into response light fractions including an underlayer light fraction and a feature light fraction as well as any other background light fractions making up the response light. The physical parameter of the pattern is determined from the response light fractions and reference physical parameters) of the underlayer, which are either known a priori or determined.

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Cupertino, CA, United States of America

Abdul Rahim Forouhi