Disclosed is a method for determining an overlay error between at least two layers in a multiple layer sample. An imaging optical system is used to measure a plurality of measured optical signals from a plurality of periodic targets on the sample. The targets each have a first structure in a first layer and a second structure in a second layer. There are predefined offsets between the first and second structures. A scatterometry overlay technique is then used to analyze the measured optical signals of the periodic targets and the predefined offsets of the first and second structures of the periodic targets to thereby determine an overlay error between the first and second structures of the periodic targets.

Apparatus and methods for detecting overlay errors using scatterometry

Methods for analyzing an optical surface for an analyte of interest in a test sample and related instruments/devices are disclosed. The method entails the use of thin film optical immunoassay device whereby an analyte of interest is detected in a test sample through spectral changes in the light impinging the surface prior to and after the binding of the analyte to reactive substrate layer(s). The device includes a substrate which has a first color in response to light impinging thereon. The substrate also exhibits a second color which is different from the first color. The second color is exhibited in response to the same light when the analyte is present on the surface.

Devices and methods for detection of an analyte based upon light interference

An instrument configured and arranged to detect a change in thickness or refractive index of a thin film substrate. A method for optimizing the instrument and a method for detecting a change in thickness or refractive index of a thin film substrate.

Method and instrument for detection of change of thickness or refractive index for a thin film substrate

The present invention relates to overlay marks and methods for determining overlay error. One aspect of the present invention relates to a continuously varying offset mark. The continuously varying offset mark is a single mark that includes over laid periodic structures, which have offsets that vary as a function of position. By way of example, the periodic structures may correspond to gratings with different values of a grating characteristic such as pitch. Another aspect of the present invention relates to methods for determining overlay error from the continuously varying offset mark. The method generally includes determining the center of symmetry of the continuously varying offset mark and comparing it to the geometric center of the mark. If there is zero overlay, the center of symmetry tends to coincide with the geometric center of the mark. If overlay is non zero (e.g., misalignment between two layers), the center of symmetry is displaced from the geometric center of the mark. The displacement in conjunction with the preset gain of the continuously varying offset mark is used to calculate the overlay error.

Continuously varying offset mark and methods of determining overlay

Plane polarized light is reflected from a surface of a sample film to produce an elliptically polarized reflected beam The reflected beam is passed sequentially through a rotating one-quarter wave plate and a fixed analyzer which transmits a beam whose intensity varies as a function of the rotational angle of the plate The transmitted beam impinges upon a photodetector which produces an electric signal proportional to the intensity of the transmitted light The rotating one-quarter wave plate cyclically varies the polarization of the beam, so that the electrical signal, when numerically Fourier analyzed, provides Fourier coefficients having both sin Δ and cos Δ terms, where the ellipsometric parameter Δ is the instantaneous phase difference between the parallel (Rp) and perpendicular (Rs) components of the electric vector of the elliptically polarized reflected beam; therefore, the phase difference Δ is uniquely and unambiguously defined in a single measurement Furthermore, the presence of both sin Δ and cos Δ terms permits Δ to be determined more accurately than is possible with the prior art rotating-analyzer ellipsometer Since the ellipsometric parameter ψ is also uniquely defined (tanψ=Rp /Rsub s), properties of the sample film can be computed Alternatively, the rotating quarter-wave plate may be placed in the path of the incident plane polarized beam

Rotating-compensator ellipsometer

An ellipsometric device and method for applying a phase modulation and a polarization direction modulation to a beam of light at two different frequencies and using a polarized parallel monochromatic light beam, a polarization modulator, a phase modulator, and means to angularly displace with respect to each other, an assembly having on one hand a beam polarizer phase and azimuth modulator and on the other hand the sample, an equalizer, analyzer and photoreceiver.

Goetz Wilmanns Ingo

Papers

Ellipsometric method and device

Verfahren zur optischen Ellipsometric von Materialproben