An optical scanning system including a radiating source that outputs a light beam, a time varying beam reflector that reflects the light beam through a scan lens towards a transparent sample, a focusing lens configured to be irradiated by light scattered from the transparent sample, and a detector that is irradiated by the light scattered from the transparent sample. The detector outputs a signal that indicates an intensity of light measured by the detector. None of the light scattered from the transparent sample is blocked. The light scattered from the transparent sample is scattered from the top surface of the transparent sample, the bottom surface of the transparent sample, or any location in between the top surface of the transparent sample and the bottom surface of the transparent sample.

An ellipsometer includes a light source, a polarizer, an asymmetric wavelength retarder, an analyzer and an optical detection component. The light source is configured to provide a light beam having multiple wavelengths incident to a sample. The polarizer is disposed between the light source and the sample, and configured to polarize the light beam. The asymmetric wavelength retarder is configured to provide a varied retardation effect on the light beam varied by wavelength. The analyzer is configured to analyze a polarization state of the light beam reflected by the sample. The optical detection component is configured to detect the light beam from the analyzer.

An optical metrology device includes an aperture that can be adjusted based on the thickness of the film on a sample. The aperture is adjusted to have a first aperture configuration or a second aperture configuration, where the second aperture configuration allows more light to pass. The aperture may be adjusted to use the second aperture configuration, e.g., if the thickness of the film produces a lateral shift from each internal reflection in the film at least 80% of the measurement spot size or the film thickness is greater than a predesignated amount, or if the light measured with the first aperture configuration and second aperture configuration differs by more than a predetermined threshold. The aperture may be in the source arm of the optical system, e.g., between the light source and the sample, or the receiver arm of the optical system, e.g., between the sample and the detector.

Methods and systems for performing spectroscopic measurements of asymmetric features of semiconductor structures are presented herein. In one aspect, measurements are performed at two or more azimuth angles to ensure sensitivity to an arbitrarily oriented asymmetric feature. Spectra associated with one or more off-diagonal Mueller matrix elements sensitive to asymmetry are integrated over wavelength to determine one or more spectral response metrics. In some embodiments, the integration is performed over one or more wavelength sub-regions selected to increase signal to noise ratio. Values of parameters characterizing an asymmetric feature are determined based on the spectral response metrics and critical dimension parameters measured by traditional spectral matching based techniques.

A thin film analysis apparatus and method for a curved surface is disclosed. The apparatus includes an illuminator, a sample, an imaging group, one or more beamsplitters, optional focusing groups, polarization analyzers, detectors and optional display and analysis systems. The image series are recorded, preferably substantially synchronously. The system can be calibrated by as few as one reference phantom that has the same or substantially similar geometry as the sample under test. Based on calibration, a lookup table of the effective reflectance can be created, which is proportional to the portion of the light that reaches the detectors, or the mutual subtraction of the effective reflectance values of all possible combinations of the unknown optical parameters within certain search ranges of the sample. The experimentally measured results are compared with the lookup table, and optical properties, for example, the thicknesses and refractive indices of the thin film can be determined.

Methods and systems for measuring optical properties of transistor channel structures and linking the optical properties to the state of strain are presented herein. Optical scatterometry measurements of strain are performed on metrology targets that closely mimic partially manufactured, real device structures. In one aspect, optical scatterometry is employed to measure uniaxial strain in a semiconductor channel based on differences in measured spectra along and across the semiconductor channel. In a further aspect, the effect of strain on measured spectra is decorrelated from other contributors, such as the geometry and material properties of structures captured in the measurement. In another aspect, measurements are performed on a metrology target pair including a strained metrology target and a corresponding unstrained metrology target to resolve the geometry of the metrology target under measurement and to provide a reference for the estimation of the absolute value of strain.

Methods and systems for performing spectroscopic measurements of semiconductor structures including ultraviolet, visible, and infrared wavelengths greater than two micrometers are presented herein. A spectroscopic measurement system includes a combined illumination source including a first illumination source that generates ultraviolet, visible, and near infrared wavelengths (wavelengths less than two micrometers) and a second illumination source that generates mid infrared and long infrared wavelengths (wavelengths of two micrometers and greater). Furthermore, the spectroscopic measurement system includes one or more measurement channels spanning the range of illumination wavelengths employed to perform measurements of semiconductor structures. In some embodiments, the one or more measurement channels simultaneously measure the sample throughout the wavelength range. In some other embodiments, the one or more measurement channels sequentially measure the sample throughout the wavelength range.

An optical metrology device includes an aperture that can be adjusted based on the thickness of the film on a sample. The aperture is adjusted to have a first aperture configuration or a second aperture configuration, where the second aperture configuration allows more light to pass. The aperture may be adjusted to use the second aperture configuration, e.g., if the thickness of the film produces a lateral shift from each internal reflection in the film at least 80% of the measurement spot size or the film thickness is greater than a predesignated amount, or if the light measured with the first aperture configuration and second aperture configuration differs by more than a predetermined threshold. The aperture may be in the source arm of the optical system, e.g., between the light source and the sample, or the receiver arm of the optical system, e.g., between the sample and the detector.

A substrate inspection apparatus includes a light irradiating unit irradiating first light to an inspection target on a stage, a light detecting unit detecting second light reflected by the inspection target, a spectrum generator generating a first spectrum from the second light, a noise filter module removing a noise signal from the first spectrum to generate a second spectrum, a spectrum analyzer determining a first calibration parameter and a first calibration value thereof from the second spectrum, and a hardware controller adjusting at least one of the stage, the light irradiating unit and the light detecting unit using the first calibration parameter and the first calibration value.

The embodiments disclosed herein can enable a target on a semiconductor wafer to be reconstructed and/or imaged. A surface of a target on a semiconductor wafer is measured using a wafer metrology tool. A voxel map of the surface is fixed to match geometry measurements and using scattering density of expected materials. Uniform scaling of the scattering density of all fixed surface voxels can occur.