There is provided a method for measuring a film thickness of a thin film in a nitride semiconductor laminate having the thin film homoepitaxially grown on a substrate comprising group-III nitride semiconductor crystal, wherein the film thickness of the thin film is measured using the substrate having a carrier concentration and an infrared absorption coefficient which are interdependent, and using Fourier Transform Infrared Spectroscopy method or Infrared Spectroscopic Ellipsometry method.

The prism coupling methods disclosed herein are directed to determining a stress characteristic of an original IOX article having a buried IOX region with a buried refractive index profile that is problematic in the sense that it prevents the original IOX article from being measured using a prism coupler system. The methods include modifying the buried IOX region of the original IOX article in a surface portion of the buried IOX region to form a modified IOX article having an unburied refractive index profile that allows the modified IOX article to be measured using a prism coupler. The methods also include measuring a mode spectrum of the modified IOX article using the prism coupler system. The methods further include determining one or more stress characteristic of the original IOX article from the mode spectrum of the modified IOX article.

A metrology device that can determine at least one characteristics of a sample is disclosed. The metrology device includes an optical system that uses spatially coherent light with a first and a second objective lens as well as a detector that detects light reflected from the sample. The objective lenses use numerical apertures sufficient to produce a small probe size, e.g., less than 200 m, while a spatial filter is used to reduce the effective numerical aperture of the optical system as seen by the detector to avoid loss of information and demanding computation requirements caused by the large angular spread due to large numerical apertures. The spatial filter permits light to pass in a desired range of angles, while blocking the remaining light and is positioned to prevent use of the full spatial extent of at least one of the first objective lens and the second objective lens.

An integrated system operation method is disclosed that includes the following steps: the film of a substrate is measured by a metrology apparatus to obtain a film information. The substrate is moved from the metrology apparatus to a process apparatus adjacent to the transfer apparatus. The film information is sent to the process apparatus. A film treatment is applied to the substrate in accordance with the film information.

The invention discloses a rapid measurement method for an ultra-thin film optical constant, which includes following steps: S1: using a p-light amplitude reflection coefficient r.sub.p and an s-light amplitude reflection coefficient r.sub.s of an incident light irradiating to an ultra-thin film to be measured to express an amplitude reflection coefficient ratio of the ultra-thin film:

[00001]$=\frac{r_p}{r_s};$

S2: performing a second-order Taylor expansion to

[00002]$=\frac{r_p}{r_s}$

at d.sub.f=0 while taking 2d.sub.f/ as a variable to obtain a second-order approximation form; S3: performing merging, simplifying and substituting processing to the second-order approximation form for transforming the same into a one-variable quartic equation; S4: solving the one-variable quartic equation to obtain a plurality of solutions of the optical constant of the ultra-thin film, and obtaining a correct solution through conditional judgment, so as to achieve the rapid measurement for the ultra-thin film optical constant.

Methods and systems for imaging precision ellipsometry of a sample are provided. The method includes shining a source of linearly polarised light on a surface of the sample wherein light reflected off the surface of the sample has elliptic polarisation. The method further includes converting polarisation of the light reflected off the surface of the sample into linear polarisation suitable for a polarisation modulator by a retarder and oscillating a polarisation modulator to measure the polarisation rotation of the polarised light passing through the retarder. In addition, the method includes synchronising acquisition of images of the light from the retarder with oscillations of the polarisation modulator to acquire first array images during positive half-periods of oscillations of the polarisation modulator and to acquire second array images during negative half-periods of the oscillations of the polarisation modulator. Finally, the method includes differential image processing of the first array images and the second array images to generate difference images comprising a plurality of pixels, the value of each of the plurality of pixels in each of the difference images being proportional to the polarisation rotation of the light reaching the polarisation modulator from the sample.

Methods and systems for estimating values of parameters of interest from optical measurements of a sample early in a production flow based on a multidimensional optical dispersion (MDOD) model are presented herein. An MDOD model describes optical dispersion of materials comprising a structure under measurement in terms of parameters external to a base optical dispersion model. In some examples, a power law model describes the physical relationship between the external parameters and a parameter of the base optical dispersion model. In some embodiments, one or more external parameters are treated as unknown values that are resolved based on spectral measurement data. In some embodiments, one or more external parameters are treated as known values, and values of base optical dispersion model parameters, one or more external parameters having unknown values, or both, are resolved based on spectral measurement data and the known values of the one or more external parameters.

An optical metrology device produces light in a spectral range for measurement of a sample using a tunable Quantum Cascade Laser (QCL). The optical metrology device includes a second channel that is used to diagnose when the tunable QCL is in failure mode, e.g., when it is not producing all wavelengths in the plurality of different wavelength ranges. The second channel includes at least one optical flat that is transmissive to the light produced by the QCL and is separate from the tunable QCL. The optical flat is switchably placed in a beam path of the light produced by the tunable QCL and light transmitted through the optical flat is received by a detector. Using output signals from the detector, a failure mode of the tunable QCL may be determined.

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 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.