Abstract: Standard patterns of differential values of interference light that correspond to a predetermined step height of the first material being processed and standard patterns of differential values of interference light that correspond to a predetermined remaining mask layer thickness of the material are set. These standard patterns use wavelengths as parameters. Then, the intensities of interference light of multiple wavelengths are measured for a second material that has the same structure as the first material. Actual patterns with wavelength as parameter are determined from differential values of the measured interference light intensities. Based on the standard patterns and the actual patterns of the differential values, the step height and the remaining mask layer thickness of the second material are determined.

Abstract: An interferometer includes a two-frequency laser and a polarizing beam splitter (PBS) that separates a heterodyne beam from the laser into separate beams having different the frequencies and orthogonal polarizations. Optical fibers conduct the separate beams to a beam combiner for interferometer optics. The PBS and/or the beam combiner can use a coating to reflect one linear polarization and transmit an orthogonal linear polarization. To improve extinction ratios in the PBS or the beam combiner, a yaw angle for an input beam is non-zero and corresponds to a peak in the extinction ratio of a reflected beam.

Abstract: An interferometer returns parallel beams that are subject to walk-off caused by reflector misalignment for an additional pass through the interferometer optics and thereby eliminates beam walk-off. A return reflector can be a plane mirror that directs returning beams to retrace paths through the interferometer optics to combine and exit along the axis of the input beam. Separation optics can separate the combined beam from the input beam. Alternatively, a return reflector such as an isosceles prism or a trapezoidal prism reflects and offsets returning beams so that the combined beam is offset from the input beam. The return reflector more generally responds to a shift in incident beam position with a matching shift of the reflected beam in contrast to a retroreflector, which shifts a reflected beam in a direction opposite to the shift in the incident beam.

Abstract: The measurement of the wavelength shifts in the reflectometric interference spectra of a porous semiconductor substrate such as silicon, make possible the highly sensitive detection, identification and quantification of small analyte molecules. The sensor of the subject invention is effective in detecting multiple layers of biomolecular interactions, termed “cascade sensing”, including sensitive detection of small molecule recognition events that take place relatively far from the semiconductor surface.

Abstract: A substrate is etched in a vacuum enclosure in a process which generates plasma light emission. The process is monitored by passing emitted light via a window, a thin film narrow band filter and a “Fabry-Perot” etalon to a detector. The output signal from the detector is analyzed by shape recognition techniques to derive a measure of the progress of the process. The shape recognition preferably makes use of digital filtering and comparison with reference data derived from the theoretical analysis or from a calibration run.

Abstract: An interferometric system for measuring the radius of curvature of a measurement object that includes a tunable coherent radiation source capable of emitting a radiant energy beam having a characteristic wavelength and of scanning the characteristic wavelength over a range of wavelengths; an unequal path interferometer which during operation includes a reference object and the measurement object and which receives a portion of the radiant energy beam from the tunable radiant energy source and generates an optical interference pattern; a detecting system including a detector for receiving the optical interference pattern; and a system controller connected to the tunable radiant energy source and the detecting system.

Abstract: A highly sensitive accelerometer for determining the acceleration of a structure includes a mass within a housing rotationally supported by a hinge and opposing support members. The support members are alternately wound around a fixed mandrel and the mass in a pendulum arrangement. At least a portion of one of the support members comprises a transducer capable measuring the rotation of the mass within the housing. An embodiment of the invention employs optical fiber coils as support members for use in interferometric sensing processes. Arrays of such interferometer based accelerometers maybe multiplexed using WDM or similar methods.

Abstract: In one aspect, the invention features an angle-measuring interferometry system that includes an interferometer which during operation directs a measurement beam to contact a measurement object, the interferometer comprising a beam steering assembly having a beam steering element positioned to contact and direct the measurement beam and an electronic positioning system to selectively orient the beam steering element within the interferometer. The angle-measuring interferometry system also includes an angle measurement system which during operation calculates a change in angular orientation of the measurement object based on a measurement signal derived from the measurement beam, wherein the measurement signal is derived from at least one interferometric signal produced by combining at least a portion of the measurement beam with a second beam after the measurement beam contacts the measurement object.

Abstract: A rotary position measuring system having a housing connected with a scanning unit having a light source that emits beams of light and a detector element. A reflection scanning graduation structure arranged directly on the housing opposite the scanning unit. A graduated disk is connected with a rotatable shaft and has a radial transmission measuring graduation structure, wherein the graduated disk is arranged so it is rotatable around an axis of symmetry in the housing so that the measuring graduation structure is located between the scanning unit and the scanning graduation structure. The beams of light emitted by the light source first reach the measuring graduation structure where they are split into a first set of diffracted partial beams of different orders and the diffracted partial beams impinge on the scanning graduation structure.

Abstract: An optical gyroscope (100) has a detection light guide body (100S) and a light measuring board (140). The detection light guide body (100S) is formed by stacking light guide layers (110, 120) and protective layers (130) alternately. An eddy-shaped light guide path section is provided in each of the light guide layers (110, 120), and the light guide path sections are optically connected to each other through said protective layers (130) to form an integral light guide path (100L). One end (100La) of the light guide path (100L) is directly connected to the light measuring board (140), and another end (100Lb) of the same is connected to the light measuring board (140) through an optical fiber (143).

Abstract: An apparatus for measuring an object's surface shape that obtains complex amplitude at a plurality of positions substantially in the directions of the optical axis of the light reflected by the object and calculates the first surface shape of the object by the depth-from-focus principle. On the other hand, using the phase data of the complex amplitude, the apparatus can measure a micro shape in the sub-fringe order by ordinary laser interference measurement. The first surface shape data are applied to a region including a step of a height greater than ½ of the light's wavelength and second surface shape data are applied to the other region.

Abstract: Techniques and devices using a fiber to couple light efficiently and compactly in a direction transverse to the fiber core for optical sensing, optical switching, and optical data storage applications. Devices are described for all-fiber optical switching, multiple-disk high-data-rate optical disk drives with compact optical fiber read/write heads, compact fiber-optic interferometers for position, measurements, and endoscopic probes for medical tissue modification and measurement.

Abstract: A confocal three dimensional inspection system, and process for use thereof, allows for rapid inspecting of bumps and other three dimensional (3D) features on wafers, other semiconductor substrates and other large format micro topographies. The sensor eliminates out of focus light using a confocal principal to create a narrow depth response in the micron range.

Abstract: One aspect of the present invention relates to a system and method for controlling an EUV mask fabrication process using a scatterometer. The system includes an EUV mask fabrication system comprising a translucent substrate having one or more layers of reflective material formed thereon and a patterned photoresist layer as the uppermost layer, a mask inspection system operatively connected to the mask fabrication system for examining the layers as they are being etched and developed by the mask fabrication system and generating data related thereto, and an EUV mask fabrication control system coupled to the mask inspection system for receiving data from the inspection system in order to regulate the mask fabrication system to facilitate obtaining desired critical dimensions. The method involves monitoring the etching of the features, generating data related to the features, and relaying the data to a control system to optimize the EUV mask fabrication process.

Abstract: Interferometric scanning method(s) and apparatus for measuring rotationally and non-rotationally symmetric test optics either having aspherical surfaces or that produce aspherical wavefronts. A spherical or partial spherical wavefront is generated from a known origin along an optical axis. The test optic is aligned with respect the optical axis and selectively moved along it relative to the known origin so that the spherical wavefront intersects the test optic at the apex of the aspherical surface and at radial positions where the spherical wavefront and the aspheric surface intersect at points of common tangency.

Abstract: The invention uses the phase shifting diffraction interferometer (PSDI) to provide a true point-by-point measurement of absolute flatness over the surface of optical flats. Beams exiting the fiber optics in a PSDI have perfect spherical wavefronts. The measurement beam is reflected from the optical flat and passed through an auxiliary optic to then be combined with the reference beam on a CCD. The combined beams include phase errors due to both the optic under test and the auxiliary optic. Standard phase extraction algorithms are used to calculate this combined phase error. The optical flat is then removed from the system and the measurement fiber is moved to recombine the two beams. The newly combined beams include only the phase errors due to the auxiliary optic. When the second phase measurement is subtracted from the first phase measurement, the absolute phase error of the optical flat is obtained.

Abstract: A method for determining a film thickness in a semiconductor substrate is provided. The method initiates with providing multiple layers on the semiconductor substrate. Then, two reflectance spectra are generated where each of the two reflectance spectra are associated with different time periods while an upper layer is being removed. Next, a difference between the two reflectance spectra is calculated. Then, a curve is defined from the difference between the two reflectance spectra. Next, the defined curve is fitted by a known parametric function to determine the film thickness. An endpoint detector and a CMP system are also provided.

Abstract: Laser ablation combined with spectrometric analysis is a good tool for determining the composition of heterogeneous materials. By measuring the depth of an ablation crater at a target of a heterogeneous material, it is possible to generate a compositional profile as a function of the depth. It is also possible to generate a 3 dimensional profile by depth profiling of a plurality of craters. The depth measurement is conducted in situ and in real time so that the evolution of composition as a function of the depth can be measured. An interferometric technique with a short coherence length light is one of the preferred embodiments for measuring the depth in situ and in real time.

Abstract: A method of aligning an optical fiber to an integrated optical circuit includes positioning the optical fiber at a first workstation such that a fast axis of the optical fiber is oriented at a first angular position, and securing the optical fiber to a glass block in that position. Then, positioning the integrated optical circuit at a second workstation such that a fast axis of the integrated optical circuit is oriented at the first angular position, and positioning the glass block and optical fiber at the second workstation with the optical fiber adjacent to the integrated optical circuit, so that the fast axis of the optical fiber is oriented at the first angular position. The free end of the optical fiber is illuminated, and the fiber is rotated until the integrated optical circuit detects a maximum throughput across the interface between the optical fiber and the integrated optical circuit.

Abstract: The invention allows for the accurate, real-time readout of the optical frequency of a swept-wavelength laser device by counting the number of fringes of a calibrated etalon that occur as the laser is swept. The distinguishing feature of the present invention is that the etalon fringe signal is phase-locked to a slave signal of a higher multiple frequency. The higher frequency of the slave signal divides the frequency interval of the etalon fringe spacing by the additional frequency multiple. The slave signal therefore generates a scale for optical frequency that is of higher resolution than possible with the etalon alone. The phase-lock also insures that the slave signal tracks monotonic scans of the optical frequency regardless of scan profile. The invention also allows for the precise, real-time control of the optical frequency of a laser during the sweep of the laser.