Abstract: 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.

Abstract: 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 ? of the sample. The local parameter ? 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 ? is selected such that it is substantially constant or uniform over the illuminated area.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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°, 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.

Abstract: 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 ??, 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 “n&k” parameters can be obtained by using only measurement tool, in contrast to two (or more) simultaneous measurement tools used in the prior art.

Abstract: 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 “n&k” parameters can be obtained by using only measurement tool, in contrast to two (or more) simultaneous measurement tools used in the prior art.

Abstract: 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.

Abstract: 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 SiOxNy. 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.

Abstract: 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 Eg 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.

Abstract: 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 SiOxNy. 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.

Abstract: 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.

Abstract: An apparatus uses reflectance spectrophotometry to characterize a sample having any number of thin films. The apparatus uses two toroidal mirrors in an optical relay to direct light reflected by the sample to a spectroscopic device. A computer then analyzes the reflected spectrum to characterize the optical properties of the sample. The optical relay allows a range of angles of reflection from the sample, and has no chromatic aberration. The optical relay is also arranged so that the non-chromatic aberration is minimized. For polarization-based measurements polarizing elements can be used in the apparatus and the spectroscopic device can be a spectroscopic ellipsometer. The sample is mounted on a movable stage so that different areas of the sample may be characterized. Furthermore, a deflector and a viewer are used to allow the operator of the apparatus to view the region of the sample under study.

Abstract: A method and apparatus for optically determining a physical parameter of an underlayer such as the underlayer refractive index N.sub.u, extinction coefficient k.sub.u and/or thickness t.sub.u through a top layer having a first top layer thickness t.sub.1 and an assigned refractive index index n.sub.t and coefficient of extinction k.sub.t. The values of index n.sub.t and extinction coefficient k.sub.t can be estimated, optically determined or assigned based on prior knowledge. In a subsequent step a first reflectance R.sub.1 is measured over a wavelength range .DELTA..lambda. by using a test beam spanning that wavelength range. Then, a second reflectance R.sub.2 of the top layer and underlayer is measured using the test beam spanning wavelength range .DELTA..lambda. at a second top layer thickness t.sub.2. In a calculation step the physical parameter of the underlayer is determined from the first reflectance measurement R.sub.1, the second reflectance measurement R.sub.