Abstract: Technologies for silicon diffraction gratings are disclosed. In some embodiments, grating lines of the diffraction gratings may have several sub-lines that make up each grating line of the diffraction grating. The sub-lines may be sub-wavelength features. In some embodiments, several silicon diffraction gratings may be made from a wafer, such as a wafer with a diameter of 300 millimeters. The wafer may be etched precisely across the entire wafer, leading to a high yield of the diffraction gratings.

Abstract: A DUV scanned-spot-array lithography system comprises an array of phase- Fresnel microlenses, which focus multiple radiation beams through intermediate foci at the object surface of a projection system. The intermediate foci are imaged by the projection system onto corresponding focused-radiation spots on an image plane, and the spots expose a photosensitive layer proximate the image plane as the layer is scanned in synchronization with modulation of the beams. The modulators may comprise micromechanical shutters proximate the intermediate foci for ON/OFF switching, in series with transmission grating modulators for gray-level control, and the microlenses may also be actuated to provide dynamic beam centering control. A nodal line printing technique may be used to provide ultra-high-resolution and high-throughput maskless printing capability in conjunction with multi-patterning or dual-wavelength recording processes.

Abstract: A plasma-generated EUV light source uses an EUV-diffracting collection mirror to channel spectrally pure in-band radiation through an intermediate-focus aperture and through EUV illumination optics. Out-of-band radiation is either undiffracted by the collection mirror or is diffractively scattered away from the aperture. The undiffracted portion, plus plasma-emitted radiation that does not intercept the collection mirror, can be efficiently recycled back to the plasma via retroreflecting mirrors, cat's-eye reflectors, or corner-cube reflectors, to enhance generation of in-band EUV radiation by the plasma.

Abstract: A DUV scanned-spot-array lithography system comprises an array of phase-Fresnel microlenses, which focus multiple radiation beams through intermediate foci at the object surface of a projection system. The intermediate foci are imaged by the projection system onto corresponding focused-radiation spots on an image plane, and the spots expose a photosensitive layer proximate the image plane as the layer is scanned in synchronization with modulation of the beams. The modulators may comprise micromechanical shutters proximate the intermediate foci for ON/OFF switching, in series with transmission grating modulators for gray-level control, and the microlenses may also be actuated to provide dynamic beam centering control. A nodal line printing technique may be used to provide ultra-high-resolution and high-throughput maskless printing capability in conjunction with multi-patterning or dual-wavelength recording processes.

Abstract: In a scanned-spot-array lithography system, a modulated array of radiant-energy source spots is imaged by a projection lens onto a printing surface, which is scanned in synchronization with the spot modulation to print a synthesized, high-resolution raster image. Similarly, in a scanned-spot-array microscopy system, an array of radiant-energy source spots is imaged by a projection lens onto an inspection surface, and radiation reflected from or transmitted through the image spots is collected and detected to acquire a synthesized, high-resolution raster image of the surface. In either case, the spot-generation optics can be configured to counterbalance and neutralize imperfect imaging characteristics of the projection lens, enabling perfectly flat-field, distortion-free, and aberration-free point imaging of the entire spot array.

Abstract: In an EUV scanned-spot-array lithography system, a modulated array of radiation beams diverging from object spots on an object surface and is projected onto a printing surface via a two-mirror projection system similar to a flat-image, Schwarzschild system. Each beam converges to a diffraction-limited image point on the surface, and the surface is scanned in synchronization with the beam modulation to print a synthesized, high-resolution raster image. The spot-generation optics can be configured to compensate for object field curvature, distortion, and geometric point-imaging aberrations in the projection system, enabling diffraction-limited printing without coherent proximity effects over the full image field. The spot-generation optics can use either micromirrors or transmitting microlenses, and can be diffractive (e.g., phase-Fresnel lenses) or non-diffractive.

Abstract: Optical radiation patterns at two wavelengths, an “imaging” wavelength and a “masking” wavelength, are superimposed on a photochromic layer, wherein the masking wavelength induces optical absorbance in the layer, allowing the imaging wavelength to transmit only through narrow transmittance zones where the masking-wavelength radiation has an optical null. The patterns are preferably formed as a focal-point array. At each focal point a focused-radiation spot at the imaging wavelength is superimposed with an annular-radiation spot at the masking wavelength. The spots may be generated by an array of microlenses with focal points proximate the layer. (Several novel types of dual-wavelength microlenses are disclosed.) Alternatively, the focused-radiation spots may be generated in separate optical paths for the two wavelengths, and optically combined at the photochromic layer by means of beam-combining and projection optics.

Abstract: A “Stacked-Grating Light Modulator” (“SGLM”) comprises two diffraction grating elements, a reflection grating and a transmission grating, in close parallel proximity. An incident beam transmits through the transmission grating and is reflected by the reflection grating back through the transmission grating. The relative lateral position of the two gratings is varied to modulate the beam's zero-order reflectance.

Abstract: In an EUV scanned-spot-array lithography system, a modulated array of radiation beams diverging from object spots on an object surface and is projected onto a printing surface by means of a two-mirror projection system similar to a flat-image, Schwarzschild system. Each beam converges to a diffraction-limited image point on the surface, and the surface is scanned in synchronization with the beam modulation to print a synthesized, high-resolution raster image. The spot-generation optics can be configured to compensate for object field curvature, distortion, and geometric point-imaging aberrations in the projection system, enabling diffraction-limited printing without coherent proximity effects over the full image field. The spot-generation optics can comprise either micromirrors or transmitting microlenses, and can be diffractive (e.g., phase-Fresnel lenses) or non-diffractive.

Abstract: A “Stacked-Grating Light Modulator” (“SGLM”) comprises two diffraction grating elements, a reflection grating and a transmission grating, in close parallel proximity. An incident beam transmits through the transmission grating and is reflected by the reflection grating back through the transmission grating. The relative lateral position of the two gratings is varied to modulate the beam's zero-order reflectance.

Abstract: A scanning microlens-array printer comprises an optical focus/alignment subsystem in which the optical sensor elements are integrated within a microlens printhead unit. The unit also incorporates an integrated spatial light modulator; thus the printhead incorporates all the critical optomechanical components necessary for high-resolution, maskless, lithographic printing. Alignment is detected by an interferometric process in which a reference diffraction grating on a printing surface coherently combines two optical beams to generate an interference signal that is sensitive to the grating's lateral position. Focus sensing is effected by using the reference grating to divide a normally-incident convergent beam into two obliquely-directed reflected beams, and detecting the focus-induced translational shift in the reflected beams' focal points.

Abstract: A small-spot imaging, spectrometry instrument for measuring properties of a sample has a polarization-scrambling element, such as a birefringent plate depolarizer, incorporated between the polarization-introducing components of the system, such as the beamsplitter, and the microscope objective of the system. The plate depolarizer varies polarization with wavelength, and may be a Lyot depolarizer with two plates, or a depolarizer with more than two plates (such as a three-plate depolarizer). Sinusoidal perturbation in the resulting measured spectrum can be removed by data processing techniques or, if the depolarizer is thick or highly birefringent, the perturbation may be narrower than the wavelength resolution of the instrument.

Abstract: A small-spot imaging, spectrometry instrument for measuring properties of a sample has a polarization-scrambling element, such as a birefringent plate depolarizer, incorporated between the polarization-introducing components of the system, such as the beamsplitter, and the microscope objective of the system. The plate depolarizer varies polarization with wavelength, and may be a Lyot depolarizer with two plates, or a depolarizer with more than two plates (such as a three-plate depolarizer). Sinusoidal perturbation in the resulting measured spectrum can be removed by data processing techniques or, if the depolarizer is thick or highly birefringent, the perturbation may be narrower than the wavelength resolution of the instrument.

Abstract: An EUV lithography system achieves high-resolution printing without the use of photomasks, projection optics, multilayer mirrors, or an extremely high-power EUV source. The system comprises a xenon laser-produced-plasma (LPP) illumination source (requiring 93 W hemispherical EUV emission in the wavelength range 10–12 nm), all-ruthenium optics (grazing-incidence mirrors and microlenses) and spatial light modulators comprising MEMS-actuated microshutters. Two 300-mm wafers are simultaneously exposed with a single 10 kHz LPP source to achieve a throughput of 6 wafers per hour, per LPP source. The illumination is focused by the microlens arrays onto diffraction-limited (42-nm FWHM) spots on the wafer plane, and the spots are intensity-modulated by the microshutters as they are raster-scanned across the wafer surface to create a digitally synthesized exposure image.

Abstract: A small-spot imaging, spectrometry instrument for measuring properties of a sample has a polarization-scrambling element, such as a birefringent plate depolarizer, incorporated between the polarization-introducing components of the system, such as the beamsplitter, and the microscope objective of the system. The plate depolarizer varies polarization with wavelength, and may be a Lyot depolarizer with two plates, or a depolarizer with more than two plates (such as a three-plate depolarizer). Sinusoidal perturbation in the resulting measured spectrum can be removed by data processing techniques or, if the depolarizer is thick or highly birefringent, the perturbation may be narrower than the wavelength resolution of the instrument.

Abstract: A database interpolation method is used to rapidly calculate a predicted optical response characteristic of a diffractive microstructure as part of a real-time optical measurement process. The interpolated optical response is a continuous and (in a preferred embodiment) smooth function of measurement parameters, and it matches the theoretically-calculated optical response at the database-stored interpolation points.

Abstract: A method for rapidly analyzing data gathered during scatterometry and related methods uses a combination of database lookup, database interpolation and theoretical model evaluation. Database lookup is used to provide an initial mapping between a measured optical response and a set of associated measurement parameters. Interpolation is then used to refine the optical response and parameters. A theoretical model is then repeatedly evaluated to refine the optical response and parameters previously refined by the interpolation. In this way, the present invention avoids the inaccuracies associated with traditional interpolation-based analysis and without incurring the computational complexity associated with real-time database supplementation.

Abstract: A method of measuring at least one parameter associated with a portion of a sample having formed thereon one or more structures with at least two zones each having an associated zone reflectance property. The method includes the steps of illuminating the zones with broadband light, and measuring at least one reflectance property of light reflected from the at least two zones. The measurement includes a substantial portion of non-specularly scattered light, thereby increasing the quality of the measurement. The method further includes the step of fitting a parameterized model to the measured reflectance property. The parameterized model mixes the zone reflectance properties of the zones to account for partially coherent light interactions between the two zones.

Abstract: Alignment accuracy between two or more patterned layers is measured using a metrology target comprising substantially overlapping diffraction gratings formed in a test area of the layers being tested. An optical instrument illuminates all or part of the target area and measures the optical response. The instrument can measure transmission, reflectance, and/or ellipsometric parameters as a function of wavelength, polar angle of incidence, azimuthal angle of incidence, and/or polarization of the illumination and detected light. Overlay error or offset between those layers containing the test gratings is determined by a processor programmed to calculate an optical response for a set of parameters that include overlay error, using a model that accounts for diffraction by the gratings and interaction of the gratings with each others' diffracted field. The model parameters might also take account of manufactured asymmetries.

Abstract: A reduced multicubic database interpolation method is provided. The interpolation method is designed to map a function and its associated argument into an interpolated value using a database of points. The database is searched to locate an interpolation cell that includes the function argument. The interpolation cell is used to transform the function argument to reflect translation of the interpolation cell to a unit cell. The interpolated value is then generated as a cubic function using the data points that correspond to vertices of the unit cell. All of the derivatives in the cubic function are simple and the interpolation accuracy order is higher than first-order.