Abstract: Non-imaging measurement is made of misalignment of lithographic exposures by illuminating periodic features of a mark formed by two lithographic exposures with broadband light and detecting an interference pattern at different wavelengths using a specular spectroscopic scatterometer including a wavelength dispersive detector. Misalignment can be discriminated by inspection of a spectral response curve and by comparison with stored spectral response curves that may be empirical data or derived by simulation. Determination of best fit to a stored spectral curve, preferably using an optimization technique can be used to quantify the detected misalignment. Such a measurement may be made on-line or in-line in a short time while avoiding tool induced shift, contact with the mark or use of a tool requiring high vacuum.

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 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: A linearly polarized light comprised of two linearly polarized components, orthogonal to each other and with split optical frequencies, is directed toward a film. A detector receives the beam prior to incidence on the film layer and generates a reference signal. The reflected beam is diffracted into zeroth- and first-order bands, which are then detected by separate detectors; a measurement signal is generated from the zeroth-order beam and a grating signal from the first-order beam. The zeroth-order beam's measurement signal and reference signal are analyzed by a phase detector for a heterodyne phase shift, and an accurate film thickness calculated from this phase shift by knowing a refractive index for the film. Additionally, the zeroth-order beam measurement signal is analyzed with the grating signal by a phase detector for detecting a grating phase shift induced by the grating.

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 apparatus and method for conditioning a pad used for chemical-mechanical planarization (CMP) are provided, that allow the conditioning to be performed in situ without stopping the polishing. A retractable pad-conditioning structure, e.g., conditioning tips, is positioned along the bottom perimeter of a wafer carrier. While polishing a surface of a wafer held in the middle of the wafer carrier, whenever the removal rate drops below a permissible value, the pad-conditioning structure, which rotates in unison with the wafer carrier, is lowered to contact the pad to condition the pad's surface. Since an area of the pad used for polishing the wafer is always surrounded by already conditioned pad areas and the area for polishing moves as the wafer carrier moves around on the pad surface, a substantially uniform removal rate is maintained. When the pad is sufficiently conditioned, the conditioning structure is retracted until the pad needs to be conditioned again.

Abstract: Non-imaging measurement is made of misalignment of lithographic exposures by illuminating periodic features of a mark formed by two lithographic exposures with broadband light and detecting an interference pattern at different wavelengths using a specular spectroscopic scatterometer including a wavelength dispersive detector. Misalignment can be discriminated by inspection of a spectral response curve and by comparison with stored spectral response curves that may be empirical data or derived by simulation. Determination of best fit to a stored spectral curve, preferably using an optimization technique can be used to quantify the detected misalignment. Such a measurement may be made on-line or in-line in a short time while avoiding tool induced shift, contact with the mark or use of a tool requiring high vacuum.

Abstract: An apparatus and method for conditioning a pad used for chemical-mechanical planarization (CMP) are provided, that allow the conditioning to be performed in situ without stopping the polishing. A retractable pad-conditioning structure, e.g., conditioning tips, is positioned along the bottom perimeter of a wafer carrier. While polishing a surface of a wafer held in the middle of the wafer carrier, whenever the removal rate drops below a permissible value, the pad-conditioning structure, which rotates in unison with the wafer carrier, is lowered to contact the pad to condition the pad's surface. Since an area of the pad used for polishing the wafer is always surrounded by already conditioned pad areas and the area for polishing moves as the wafer carrier moves around on the pad surface, a substantially uniform removal rate is maintained. When the pad is sufficiently conditioned, the conditioning structure is retracted until the pad needs to be conditioned again.

Abstract: An apparatus and method for conditioning a pad used for chemical-mechanical planarization (CMP) are provided, that allow the conditioning to be performed in situ without stopping the polishing. A retractable pad-conditioning structure, e.g., conditioning tips, is positioned along the bottom perimeter of a wafer carrier. While polishing a surface of a wafer held in the middle of the wafer carrier, whenever the removal rate drops below a permissible value, the pad-conditioning structure, which rotates in unison with the wafer carrier, is lowered to contact the pad to condition the pad's surface. Since an area of the pad used for polishing the wafer is always surrounded by already conditioned pad areas and the area for polishing moves as the wafer carrier moves around on the pad surface, a substantially uniform removal rate is maintained. When the pad is sufficiently conditioned, the conditioning structure is retracted until the pad needs to be conditioned again.

Abstract: A CMP heterodyne in-situ sensor (C-HIS) system utilizes optical heterodyne interferometry. A wafer undergoing CMP is illuminated through the wafer thickness using an infrared laser beam at a wavelength of 1.1 &mgr;m or greater. The beam is transmitted through the wafer and is reflected from the front wafer surface. As the wafer is polished, the optical beam path through the wafer is shortened, causing the reflected optical frequency to undergo a Doppler shift. By measuring this shift, the change in wafer thickness is determined. The frequency shift generates a signal, which enables dynamic process control. In embodiments where the wafer includes a planarization film, the frequency shift provides a measurement of changing film thickness. Embodiments of the invention utilize phase detection independent of intensity, and hence do not suffer from intensity fluctuations. Some embodiments detect thickness changes less than 2.5 nm. C-HIS sensors operate in both polished-to-thickness and polished-to-stop scenarios.

Abstract: In a CMP method and apparatus an essentially circular polishing pad is mounted on a rotating platen. A region of the polishing pad is thinned to provide enhanced optical transparency. A portion of the platen underlying the thinned pad region is also transparent. The thinned pad and the transparent platen portion provide optical access to the surface of a wafer for in-situ process monitoring. Input signals from optical monitoring instruments enable dynamic process control.

Abstract: A method and apparatus for detecting the presence of a thin film such as a photoresist film on a semiconductor wafer or other substrate. Only when a film is present does the surface reflectance (reflective power) of light incident on the wafer surface vary sinusoidally when the incidence angle of the light is varied. This sinusoidal variation in the reflected optical power is due to interference occurring between the film surface and wafer surface reflections. This method and apparatus allows determining whether an undeveloped photoresist layer is present on a wafer; this is not possible using merely visual inspection especially when an underlying pattern is present. The present method and apparatus may also be used to determine the thickness of a particular thin film.

Abstract: Macro defects in a processed or partly processed semiconductor wafer, liquid crystal display element, disk drive element or the like, are detected using scattered light. By use of automated image processing techniques, a reference image and a sample image are formed from the scattered light and edge enhanced. A difference image is formed by comparing the edge enhanced reference and sample images. The difference image is evaluated using one or more automated image processing techniques such as thresholding, morphological transformations and blob analysis to identify macro defects.

Abstract: A chemical-mechanical polishing (CMP) optical process monitor apparatus allows in situ measurement of the thickness of a thin film being polished. As the incidence angle of the incident light on the wafer being polished is changed, the reflected intensity of the light from the thin film on the wafer undergoes a variation in local maxima and minima. The angle at which the light intensity is a maximum or minimum determined by the thin film interference equation, thus providing a measurement of the thin film thickness and/or the change in the thin film thickness.

Abstract: Defects in a processed or partly processed semiconductor wafer, or other similar three-dimensional periodic pattern formed on a substrate surface, are detected by light diffraction. Incident monochromatic light is provided from an elongated and extended source to illuminate the entire wafer surface. By use of automated image processing techniques, wafer macro inspection is thereby automated. The elongated and extended light source allows light at different angles to be incident upon each point of the wafer surface, thereby allowing defect detection for an entire wafer surface in a single field of view and reducing inspection time. The particular wavelength of the incident monochromatic light is predetermined to allow optimum detection of defects in the periodic pattern on the wafer, depending on the width and pitch of the features of the periodic pattern.

Abstract: A film measurement apparatus having a stage with a support surface on which a substrate coated with a film may rest. An extended light source faces the stage, and an imager is aimed at the stage to capture the reflection of the light source. The imager includes a receiver upon which an image of at least an extended portion of the substrate may be generated, and a processor in communication with the imager is operable to calculate the thickness of the film at plurality of locations. The stage may be tilted to empirically measure an average illumination and the contrast between interference fringes, avoiding theoretical estimates provided by Fresnel'equation.

Abstract: A method of detecting particles on a wafer support surface comprising positioning a wafer in a first position on the surface with the wafer in the first position, generating a first pattern on the wafer, and moving the wafer. Then, after moving the wafer, generating a second pattern on the wafer to generate a moire pattern by the interaction of the second pattern with the first pattern. The moire pattern is inspected to identify any visual distortion in the moire pattern due to physical distortion of the wafer caused by a particle on the support surface during the generation of the first pattern. The patterns may be ruled parallel lines, and the second pattern may be moved during inspection to shift the moire pattern to reveal distortions over a wide area.

Abstract: A method of providing a beam having precisely orthogonally polarized components includes generating a beam with substantially orthogonally polarized components, splitting the beam to separate the components to separate paths, projecting each component into a respective polarization preserving optical fiber (PPF) or polarizing fiber, recombining the components output from the fibers into a single beam, and transmitting the single beam to an interferometer. The PPFs are rotationally adjustable at their output ends to provide precise orthogonality in the resulting beam.

Abstract: A light source having a solid state laser emitting a beam that is separated into a number of segments. Each segment is frequency shifted by a different amount so that the segments do not substantially overlap in the frequency domain. Each segment passes through a short focal length lens element of a fly's eye array to be dispersed onto a mask plane for evenly illuminating a mask. The lens elements of the fly's eye array are contained within a small region in comparison to the width of the dispersed beam segments, such that each beam segment contributes illumination to the entirety of a common portion of the mask.