Abstract: A sensor device which is adapted for detecting target molecules in-vitro and in-vivo, comprises a MIR source emitting in 2 um to 10 um range for exciting the target species and a probe beam with orthogonal polarizations and split frequencies in the KHz. to MHz range. The probe beam measures the effects of specie concentration change and of its excitation. The evanescent fields of the orthogonally polarized beams in the probe beam undergo differential phase shifts when target species concentration changes in epidermis or when its refractive index changes due to photo-thermal excitation by the MIR beam. The phase shift is directly proportional to concentration change and refractive index change and are measured using a heterodyne interferometer operating at the same frequency as the split frequency. The measured phase shift can be related to specie concentration change in target volume.

Abstract: A sensor device which is adapted for detecting target molecules in-vitro and in-vivo, comprises a MIR source for exciting the target species and a probe beam with split frequency to measure the effect of excitation. The latter uses a heterodyne interferometer operating at a beat frequency ˜ KHz. to MHz. The photo-thermal excitation of target species leads to refractive index change. The RI change produces probe beam displacement and is measured using a 1) grating heterodyne interferometer, 2) grating deflection amplifier and 3) evanescent field heterodyne interferometer. The measured RI change can be related to specie concentration change in target volume. Furthermore, a sensing method for detecting HbA1c concentration and its change with thermal excitation is described in terms of phase shift of the OCT spectrum obtained with spectral domain optical coherence tomography (SD-OCT).

Abstract: A sensor device which is adapted for detecting target molecules in-vitro and in-vivo, comprises a MIR source for exciting the target species and a probe beam with split frequency to measure the effect of excitation. The latter uses a heterodyne interferometer operating at a beat frequency ˜ KHz. to MHz. The photo-thermal excitation of target species leads to refractive index change. The RI change produces probe beam displacement and is measured using a 1) grating heterodyne interferometer, 2) grating deflection amplifier and 3) evanescent field heterodyne interferometer. The measured RI change can be related to specie concentration change in target volume. Furthermore, a sensing method for detecting HbA1c concentration and its change with thermal excitation is described in terms of phase shift of the OCT spectrum obtained with spectral domain optical coherence tomography (SD-OCT).

Abstract: A sensor device which is adapted for detecting target molecules having a target nucleic acid sequence located in nano/micro channels, comprises a THz source for exciting the target molecules and a heterodyne interferometer, having a detection frequency MHz, for probing the excited molecules. The nano-channel array in the sample holder is functionalized with electric field to linearize the target alleles and genes. The linearized molecules are exposed to THz field whereby the different vibrational modes of base pairs are resonantly excited. The excitation of base-breathing mode and base-shifting mode leads to differential induced dipole moments along and perpendicular to the double helix axis. This induced asymmetry in polarizability leads to optical anisotropy. The dipole-dipole interaction between adjacent bases affects polarizability along the helix axis and hence the intrinsic molecular anisotropy is a function of number of base pairs in the strand.

Abstract: An interferometer may include a tunable light source, a beam direction unit, a digital imager, and a processor system. The tunable light source may be configured to emit a beam. The beam direction unit may be configured to direct the beam toward a sample with a reference surface and a feature surface. The digital imager may be configured to receive a reflected beam and to generate an image based on the reflected beam. The reflected beam may be a coherent addition of a first reflection of the beam off the reference surface and a second reflection of the beam off the feature surface. The processor system may be coupled to the digital imager and may be configured to determine a distance between the reference surface and the feature surface based on the image.

Abstract: A system and method of measuring feature depth using a common path auto-correlation low coherence interferometer including a light source having an output directed toward a first beam splitter, the first beam splitter directing at least a portion of a light beam from the light source toward a sample having two reflective interfaces including a top surface reflective interface and a feature bottom reflective interface. The first beam splitter can also pass toward a second beam splitter each of a reference light beam reflected from the top surface interface and a measurement light beam reflected from the feature bottom reflective interface. The second beam splitter directs the reference light beam to a first mirror and the measurement light beam to a second mirror and combines a reflected measurement light beam from the second mirror and a reflected reference light beam from the first mirror to form an interference pattern.

Abstract: According to an aspect of an embodiment, a method may include measuring, based on interferometry, a film thickness of a surface film of a semiconductor wafer at a plurality of locations that are along a scanline of the wafer. The method may also include measuring, based on interferometry, a substrate thickness of a substrate of the semiconductor wafer at the plurality of locations. Moreover, the method may include measuring, based on an optical measurement technique, a curvature of the semiconductor wafer along the scanline. In addition, the method may include determining a stress of the surface film along the scanline based on the measured film thickness at the plurality of locations, based on the measured substrate thickness at the plurality of locations, and based on the measured curvature along the scanline.

Abstract: A system and method of measuring feature depth using a common path auto-correlation low coherence interferometer including a light source having an output directed toward a first beam splitter, the first beam splitter directing at least a portion of a light beam from the light source toward a sample having two reflective interfaces including a top surface reflective interface and a feature bottom reflective interface. The first beam splitter can also pass toward a second beam splitter each of a reference light beam reflected from the top surface interface and a measurement light beam reflected from the feature bottom reflective interface. The second beam splitter directs the reference light beam to a first mirror and the measurement light beam to a second mirror and combines a reflected measurement light beam from the second mirror and a reflected reference light beam from the first mirror to form an interference pattern.

Abstract: A self referencing heterodyne reflectometer is disclosed which rapidly alternates between a heterodyne reflectometry (HR) mode, in which an HR beam comprised of s- and p-polarized beam components at split angular frequencies of ? and ?+?? is employed, and a self referencing (SR) mode, in which an SR beam comprised of p-polarized beam components at split angular frequencies of ? and ?+?? is employed. Alternatively, in SR operating mode the SR beam is replaced by a p-polarized amplitude modulated (AM) beam, operating at two modulated amplitudes of ? and ?+?? at a single frequency, ??. When the two measurements are made in rapid succession, using an optical chopper switcher, temperature induced noise in the detector is be assumed to be equivalent. Film phase shift information is derived from the measured phase shift ?Ref/film, generated from the HR beam, and the reference phase shift ?Ref/Sub, generated from the SR/AM beam, which are used for calculating film thickness.

Abstract: The present invention is directed to a self referencing heterodyne reflectometer system and method for obtaining highly accurate phase shift information from heterodyned optical signals, without the availability of a reference wafer for calibrations. The self referencing heterodyne reflectometer rapidly alternates between a heterodyne reflectometry (HR) mode, in which an HR beam comprised of s- and p-polarized beam components at split angular frequencies of ? and ?+?? is employed, and a self referencing (SR) mode, in which an SR beam comprised of p-polarized beam components at split angular frequencies of ? and ?+?? is employed. When the two measurements are made in rapid succession, temperature induced noise in the detector is be assumed to be the same as for both measurements. A measured phase shift ?Ref/film is generated from the HR beam and a reference phase shift ?Ref/Sub is generated from the SR beam.

Abstract: The present invention is directed to a heterodyne reflectometer system and method for obtaining highly accurate phase shift information from heterodyned optical signals, from which extremely accurate film depths can be calculated. A linearly polarized light comprised of two linearly polarized components that are orthogonal to each other, with split optical frequencies, is directed toward a film causing one of the optical polarization components to lag behind the other due to an increase in the optical path in the film for that component. A pair of detectors receives the beam reflected from the film layer and produces a measurement signal, and the beam prior to incidence on the film layer and generates a reference signal, respectively. The measurement signal and reference signal are analyzed by a phase detector for phase shift. The detected phase shift is then fed into a thickness calculator for film thickness results.

Abstract: An optical profilometer apparatus 10 having a stage with a support surface 42 on which a wafer substrate may rest. The wafer stage is capable of moving the wafer in (x, y) or (r, ?) mode to achieve complete wafer scan. Polarized light from a monochromatic source 12 is directed towards the wafer surface 22. Surface profiling is achieved by sensing beam shift on a segmented sensor caused by level/height change at the wafer surface. In preferred embodiment of the profilometer, a single light beam is engineered to propagate in two orthogonal planes of incidence so that it becomes sensitive to height/level change on the wafer while being insensitive to local slope or wafer tilt. In another embodiment, slope of surface feature is measured. By integrating slope over the measurement spot, local feature height is obtained. This is particularly useful when the beam shift due to feature height change is below detection sensitivity.

Abstract: An alignment simulation method simulates the signal waveform for an alignment mark using various alignment methods as well as the signal strength for an alignment mark, which is useful in optimizing the thickness of one or more layers as well as the geometry of the mark. The simulation of signal strength is also useful in optimizing the thickness of a layer for artifact wafers. The alignment simulation method includes accurately modeling the alignment mark, including one or more layers of various thicknesses and materials. The accurate modeling of the alignment mark includes such things as smoothing regions of the alignment mark and generating lateral shifts of the layers. The model of the alignment mark is a series of small pixels, each including the thickness of the layers and the layers indices of refraction. Using scalar diffraction, a complex reflectivity is generated for each pixel and a fast fourier transform is performed on the series of pixels.

Abstract: A wafer inspection apparatus 10 having a stage with a support surface 42 on which a wafer substrate may rest. The wafer stage is capable of moving the wafer in (x, y) or (r, &thgr;) mode to achieve complete wafer scan. Polarized light from a monochromatic source 12 is directed towards the wafer surface 22. The state of polarization of the beam entering PBS 51 is either s- or p- or circular depending on the exemplary embodiment of the invention. Alternatively, both s- and p-polarization components are simultaneously present with the optical frequency of one of them shifted by &Dgr;f with respect to the other. The reflected light is sensed by detector(s) 16 or 160 and 161. A processor in communication with the detector(s) can generate image of the wafer surface based on reflectance data from a plurality of points generated via wafer (r, &thgr;) scan.