Abstract: An interferometer system and method may be used to measure substrate thickness or shape. The system may include two spaced apart reference flats having that form an optical cavity between two parallel reference surfaces. A substrate holder may be configured to place the substrate in the cavity with first and second substrate surfaces substantially parallel with corresponding first and second reference surfaces such that a space between the first or second substrate surface is three millimeters or less from a corresponding one of the reference surfaces or a damping surface. Interferometer devices may be located on diametrically opposite sides of the cavity and optically coupled thereto. The interferometers can map variations in spacing between the substrate surfaces and the reference surfaces, respectively, through interference of light optically coupled to and from to the cavity via the interferometer devices.

Abstract: A system with two unequal path interferometers, with a first flat, a second flat, and a cavity between the first and second flats, a holder to receive an object in the cavity such that an optical path remains open between the first and second flats, and a motor coupled to the holder such that the object may be tilted in the cavity to allow for measurements of, and a radiation assembly to direct collimated radiation to the interferometer assembly, a collecting assembly to collect radiation received from the interferometer assembly, and a controller comprising logic to; vary a wavelength of the radiation, record interferograms, extract phases of the interferograms to produce phase maps, determine from each map areas with high slopes, tilt the holder to allow measurement of the high slope areas, and process measurement that covers the entire surface of the object.

Abstract: An interferometer system and method may be used to measure substrate thickness or shape. The system may include two spaced apart reference flats having that form an optical cavity between two parallel reference surfaces. A substrate holder may be configured to place the substrate in the cavity with first and second substrate surfaces substantially parallel with corresponding first and second reference surfaces such that a space between the first or second substrate surface is three millimeters or less from a corresponding one of the reference surfaces or a damping surface. Interferometer devices may be located on diametrically opposite sides of the cavity and optically coupled thereto. The interferometers can map variations in spacing between the substrate surfaces and the reference surfaces, respectively, through interference of light optically coupled to and from to the cavity via the interferometer devices.

Abstract: In one embodiment, an interferometer system comprises an unequal path interferometer assemble comprising; a first reference flat having a first length L1 in a first dimension, a second reference flat having a second length L2 in the first dimension, a cavity D1 defined by a distance between the first reference flat and the second reference flat, and a receptacle to receive an object in the cavity such that an optical path remains open between the first reference flat and the second reference flat, and a radiation targeting assembly to direct a collimated radiation beam to the interferometer assembly, a radiation collecting assembly to collect radiation received from the interferometer assembly, and a controller comprising logic to; vary a wavelength of the collimated radiation beam, record interferograms formed by a plurality of surfaces, extract phases of each of the interferograms for each of the plurality of surfaces to produce multiple phase maps, and determine each phase map from its corresponding interf

Abstract: In one embodiment, an interferometer system comprises two unequal path interferometers assemble comprising; a first reference flat having a first length L1 in a first dimension, a second reference flat having a second length L2 in the first dimension, a cavity D1 defined by a distance between the first reference flat and the second reference flat, a wafer holder to receive an object in the cavity such that an optical path remains open at an outer annual area between the first reference flat and the second reference flat and at least one wafer holder motor coupled to the wafer holder such that an object may be tilted in the cavity as to allow for measurements of local areas of interest, and a radiation targeting assembly to direct a collimated radiation beam to the interferometer assembly, a radiation collecting assembly to collect radiation received from the interferometer assembly, and a controller comprising logic to; vary a wavelength of the collimated radiation beam, record interferograms formed by a plur

Abstract: White light interferometry is used to obtain the height information of the topmost surface of an object having a transparent thin film on it. N frames of data are acquired from an interferometer while a white light fringe pattern is scanning through a field of view. The modulation fringe envelope R(n) is calculated for every pixel; and the topmost surface position at every pixel is determined as an offset of R(n).

Abstract: In one embodiment, a system to measure defects on a surface of a wafer and an edge of the wafer using a single tool comprises a radial motor to move an optical head in a radial direction to detect defects at locations displaced from the edge of the wafer, and a rotational motor to rotate the optical head around the edge of the wafer to detect defects on the edge of the wafer.

Abstract: A method for determining the surface topography of an object with various surface properties in white light interferometry first generates a set of interferograms, produced by a phase shift driving mechanism supplied with known inputs, obtained from a single reflective surface at the location of the test piece. The sequence of interferograms from the test piece then is used to calibrate a sequence of inputs to the phase shift driving mechanism to compensate for non-linear characteristics of the phase shifting mechanism. The temporal interferometric signal or its transform at each pixel of a set of subsequently acquired interferograms from a test piece then is compared with signals or their transforms modeled with different properties of the measuring surface. The measured surface properties which generate a best match to the modeling surface properties are selected as the desired signal.

Abstract: In one embodiment, a system to measure defects on a surface of a wafer and an edge of the wafer using a single tool comprises a radial motor to move an optical head in a radial direction to detect defects at locations displaced from the edge of the wafer, and a rotational motor to rotate the optical head around the edge of the wafer to detect defects on the edge of the wafer.

Abstract: In one embodiment, an interferometer system comprises an unequal path interferometer assemble comprising; a first reference flat having a first length L1 in a first dimension, a second reference flat having a second length L2 in the first dimension, a cavity D1 defined by a distance between the first reference flat and the second reference flat, and a receptacle to receive an object in the cavity such that an optical path remains open between the first reference flat and the second reference flat, and a radiation targeting assembly to direct a collimated radiation beam to the interferometer assembly, a radiation collecting assembly to collect radiation received from the interferometer assembly, and a controller comprising logic to; vary a wavelength of the collimated radiation beam, record interferograms formed by a plurality of surfaces, extract phases of each of the interferograms for each of the plurality of surfaces to produce multiple phase maps, and determine each phase map from its corresponding interf

Abstract: A method and apparatus for analyzing a surface of a test object employs apparatus with a scanning interferometry system which generates a windowed interferometric signal from the surface of a test object to characterize the surface of the test object.

Abstract: Apparatus and methods are provided for analyzing surface characteristics of a test object using broadband scanning interferometry. Test objects amenable to these apparatus and methods include but are not limited to semiconductor wafers, semiconductor devices, metallic surfaces, and the like. An interferometry system is used to obtain an interferometry signal and related to data embodied in the signal representative of the test object surface. This signal and/or data is used to construct an n-dimensional function that includes an independent frequency variable and an independent time variable, and/or an n-dimensional function that includes an independent scale variable and an independent time variable, and/or a multi-domain function. These functions are compared with various models to obtain a best match that is then used to characterize the test object surface.

Abstract: A method and apparatus for analyzing a surface of a test object employs apparatus with a scanning interferometry system which generates a windowed interferometric signal from the surface of a test object to characterize the surface of the test object.

Abstract: Apparatus and methods are provided for analyzing surface characteristics of a test object using broadband scanning interferometry. Test objects amenable to these apparatus and methods include but are not limited to semiconductor wafers, semiconductor devices, metallic surfaces, and the like. An interferometry system is used to obtain an interferometry signal and related to data embodied in the signal representative of the test object surface. This signal and/or data is used to construct an n-dimensional function that includes an independent frequency variable and an independent time variable, and/or an n-dimensional function that includes an independent scale variable and an independent time variable, and/or a multi-domain function. These functions are compared with various models to obtain a best match that is then used to characterize the test object surface.

Abstract: White light interferometry is used to obtain the height information of the topmost surface of an object having a transparent thin film on it. N frames of data are acquired from an interferometer while a white light fringe pattern is scanning through a field of view. The modulation fringe envelope R(n) is calculated for every pixel; and the topmost surface position at every pixel is determined as an offset of R(n).

Abstract: A system and method are provided for obtaining mapping profiles of transparent objects having a plurality of reflective surfaces. The object, the surfaces of which are to be mapped, is placed in an unequal path interferometer including a reference surface located a predetermined distance from the object. Coherent light is supplied in the interferometer from a tunable source; and multiple optical interferograms for each of the plurality of reflective surfaces are simultaneously recorded. These interferograms are simultaneously extracted through the use of a dynamically generated weighted least-square fitting technique; which separates interferograms from a set of superimposed interferograms to obtain a given interferogram for any one of the surfaces, free from errors resulting from the existence of the other interferograms.

Abstract: A method and apparatus to linearize the phase shifts produced by the wavelength-varying driving mechanism of an interferometer used in phase shift interferometry for the measurement of multiple reflective surfaces first calibrates a sequence of physical values used as the input to the driving mechanism to produce a known linear or a known constant phase shift increment between any two adjacent interferograms. The calibration process, in essence, involves the determination of the sequence of physical values, such as the voltage change with respect to the time, through the process of iteration. This sequence then is used as an input to the phase shift driving mechanism for ongoing operation of the system, thereby compensating for non-linear characteristics of the system.

Abstract: The present invention consists of a technique and device for measuring the thickness variation and shape of wafers or other polished opaque plates. A combination of two improved phase-shifting Fizeau interferometers is used to simultaneously measure the single-sided distance maps between each side of the wafer and the corresponding reference flat, with the thickness variation and shape being calculated from these data. Provisions are made to determine and eliminate the shape and tilt of the reference surfaces, and also to facilitate the correct overlay of the two single-sided measurements for the calculation of thickness variation and shape.

Abstract: The present invention consists of a technique and device for measuring the thickness variation and shape of wafers or other polished opaque plates. A combination of two improved phase-shifting Fizeau interferometers is used to simultaneously measure the single-sided distance maps between each side of the wafer and the corresponding reference flat, with the thickness variation and shape being calculated from these data. Provisions are made to determine and eliminate the shape and tilt of the reference surfaces, and also to facilitate the correct overlay of the two single-sided measurements for the calculation of thickness variation and shape.

Abstract: A method and apparatus to linearize the phase shifts produced by the wavelength-varying driving mechanism of an interferometer used in phase shift interferometry for the measurement of multiple reflective surfaces first calibrates a sequence of physical values used as the input to the driving mechanism to produce a known linear or a known constant phase shift increment between any two adjacent interferograms. The calibration process, in essence, involves the determination of the sequence of physical values, such as the voltage change with respect to the time, through the process of iteration. This sequence then is used as an input to the phase shift driving mechanism for ongoing operation of the system, thereby compensating for non-linear characteristics of the system.