Abstract: Methods and systems are described for reducing particulate contaminants on a clamping face of a clamping structure in a lithographic system. A substrate such as a cleaning reticle is pressed against the clamping face. A temperature differential is established between the substrate and the clamping face either before or after clamping occurs to facilitate transfer of particles from the clamping face to the substrate.

Abstract: A method to reduce sensitivity of a level sensor, arranged to measure a height of a substrate, to variations of a property of an optical component in the level sensor includes directing a beam of radiation toward a diffractive element and directing the beam, via an optical system, to a first reflective element at a first angle of incidence. The beam has a first polarization and a second polarization that is perpendicular to the first polarization. The first reflective element reflects the beam toward a second reflective element at a second angle of incidence causing the beam to impinge on the substrate. The first and second angles of incidence are selected to reduce variations of a ratio of intensities of the first polarization to the second polarization of the beam imparted by a property of a layer of at least one of the first and second reflective elements.

Abstract: An optical element and a lithographic apparatus including the optical element. The optical element includes a first member having a curved optical surface and a heat transfer surface, and a second member that comprises at least one recess, the at least one recess sealed against the heat transfer surface to form at least one closed channel between the first member and the second member to allow fluid to flow therethrough for thermal conditioning of the curved optical surface. In an embodiment, one or more regions of the heat transfer surface exposed to the at least one closed channel are positioned along a curved profile similar to that of the curved optical surface.

Abstract: An apparatus and system for determining alignment of a substrate in which a periodic alignment mark is illuminated with spatially coherent radiation which is then provided to a compact integrated optical device to create self images of the alignment mark which may be manipulated (e.g., mirrored, polarized) and combined to obtain information on the position of the mark and distortions within the mark. Also disclosed is a system for determining alignment of a substrate in which a periodic alignment mark is illuminated with spatially coherent radiation which is then provided to an optical fiber arrangement to obtain information such as the position of the mark and distortions within the mark.

Abstract: An alignment apparatus includes an illumination system configured to direct one or more illumination beams towards an alignment target and receive the diffracted beams from the alignment target. The alignment apparatus also includes a self-referencing Interferometer configured to generate two diffraction sub-beams, wherein the two diffraction sub-beams are orthogonally polarized, rotated 180 degrees with respect to each other around an alignment axis, and spatially overlapped. The alignment apparatus further includes a beam analyzer configured to generate interference between the overlapped components of the diffraction sub-beams and produce two orthogonally polarized optical branches, and a detection system configured to determine a position of the alignment target based on light intensity measurement of the optical branches, wherein the measured light intensity is temporally modulated by a phase modulator.

Abstract: Apparatus for, and method of, measuring a parameter of an alignment mark on a substrate in which an optical system is arranged to receive at least one diffraction order from the alignment mark and the diffraction order is modulated at a pupil or a wafer conjugate plane of the optical system, a solid state optical device is arranged to receive the modulated diffraction order, and a spectrometer is arranged to receive the modulated diffraction order from the solid state optical device and to determine an intensity of one or more spectral components in the modulated diffraction order.

Abstract: A calibration system includes a plate, a fixed alignment mark, and a variable diffraction grating. The plate is adjacent to a wafer alignment mark disposed on a wafer. The fixed alignment mark is disposed on the plate and is configured to act as a reference mark for an initial calibration of the calibration system. The variable diffraction grating is disposed on the plate and includes a plurality of unit cells configured to form a plurality of variable alignment marks. The variable diffraction grating is configured to calibrate a shift-between-orders of one of the variable alignment marks and the fixed alignment mark.

Abstract: A cleaning tool configured to be inserted into a lithography apparatus in a first configuration, configured to be engaged by a handler of the lithography apparatus, and used for cleaning a portion of the lithography apparatus. The cleaning tool is configured to move from the first configuration to a second, expanded configuration, after engagement by the handler such that the cleaning tool is in the second configuration when used for cleaning the portion of the lithography apparatus. There may also be a container configured to hold the cleaning tool in the first configuration and fit into the lithography apparatus. In that case, the cleaning tool is configured to be inserted into the lithography apparatus in the container, moved from the container by the handler for the cleaning, and returned to the container by the handler after the cleaning.

Abstract: A method for source mask optimization or mask only optimization used to image a pattern onto a substrate. The method includes determining a non-uniform illumination intensity profile for illumination; and determining one or more adjustments for the pattern based on the non-uniform illumination intensity profile until a determination that features patterned onto a substrate substantially match a target design. The non-uniform illumination intensity profile may be determined based on an illumination optical system and projection optics of a lithographic apparatus. In some embodiments, the lithographic apparatus includes a slit, and the non-uniform illumination profile is a through slit non-uniform illumination intensity profile. Determining the one or more adjustments for the pattern may include performing optical proximity correction, for example.

Abstract: Methods and systems are described for reducing adhesion and controlling friction between a wafer and a wafer table during semiconductor photolithography wherein the tops of burls on the wafer table have a layer with a nanoscale topography.

Abstract: A method of applying a measurement correction includes determining an orthogonal subspace used to characterize a first principal component of the measurement and a second principal component of the measurement, and rotating the orthogonal subspace by a first angle such that the first principle component rotates to become a first factor vector and the second principle component rotates to become a second factor vector. An asymmetry vector is generated by rotating the second factor vector by a second angle, where the asymmetry vector and the first factor vector define a non-orthogonal subspace. An asymmetry contribution is determined in the measurement based on the projection of the measurement onto the first factor vector in the non-orthogonal subspace. The method also includes subtracting the asymmetry contribution from the measurement.

Abstract: A system (500) includes an illumination system (502), a lens element (506), and a detector (504). The illumination system generates a beam of radiation (510) having a first spatial intensity distribution (800) at a pupil plane (528) and a second spatial intensity distribution (900) at a plane of a target (514). The first spatial intensity distribution comprises an annular intensity profile (802) or an intensity profile corresponding to three or more beams. The lens element focuses the beam onto the target. The second spatial intensity distribution is a conjugate of the first intensity distribution and has an intensity profile corresponding to a central beam (902) and one or more side lobes (904) that are substantially isolated from the central beam. The central beam has a beam diameter of approximately 20 microns or less at the target. The detector receives radiation scattered by the target and generates a measurement signal based on the received radiation.

Abstract: An apparatus for reticle sub-field thermal control in a lithography system is disclosed. The apparatus includes a clamp configured to fix an object. The clamp includes a plurality of gas distribution features that are spatially arranged in a pattern. The apparatus further includes a gas pressure controller configured to individually control a gas flow rate through each of the plurality of gas distribution features to spatially modulate a gas pressure distribution in a space between the clamp and the object. The gas distribution features include a plurality of trenches or holes arranged in an array form.

Abstract: A substrate holder, for a lithographic apparatus, having a main body, a plurality of support elements to support a substrate and a seal unit. The seal unit may include a first seal positioned outward of and surrounding the plurality of support elements. A position of a substrate contact region of an upper surface of the first seal may be arranged at a distance from the plurality of support elements sufficient enough such that during the loading/unloading of the substrate, a force applied to the first seal by the substrate is greater than a force applied to the plurality of support elements by the substrate. A profile of the contact region, in a cross section through the seal, may have a shape which is configured such that during the loading/unloading of the substrate, the substrate contacts the seal via at least two different points of the profile.

Abstract: A method of applying a measurement correction includes determining an orthogonal subspace used to characterize the measurement as a plot of data. A first axis of the orthogonal subspace corresponds to constructive interference output from an interferometer of the metrology system plus a first error variable and a second axis of the orthogonal subspace corresponds to destructive interference output from the interferometer of the metrology system plus a second error variable. The method also includes determining a slope of the plot of data and determining a fitted line to the plot of data in the orthogonal subspace based on the slope.

Abstract: Disclosed is a method for a metrology measurement on an area of a substrate comprising at least a portion of a target structure. The method comprises receiving a radiation information representing a portion of radiation scattered by the are, and using a filter in a Fourier domain for removing or suppressing at least a portion of the received radiation information that does not relate to radiation that has been scattered by the target structure for obtaining a filtered radiation information for the metrology measurement, wherein characteristics of the filter are based on target information about the target structure.

Abstract: A structure of a semiconductor device with a sub-segmented grating structure as a metrology mark and a method for configuring the metrology mark. The method for configuring a metrology mark may be used in a lithography process. The method may include determining an initial characteristic function of an initial metrology mark disposed within a layer stack. The method also includes perturbing one or more variables of the plurality of subsegments of the metrology mark (e.g., pitch, duty cycle, and/or line width of the plurality of subsegments) and further perturbing a thickness of one or more layers within the layer stack. The method further includes iteratively performing the perturbations until a minimized characteristic function of an initial metrology mark is determined to set a configuration for the plurality of subsegments.

Abstract: A system includes a radiation source and a phased array. The phased array includes optical elements, waveguides and phase modulators. The phased array generates a beam of radiation. The optical elements radiate radiation waves. The waveguides guide radiation from the radiation source to the optical elements. The phase modulators adjust phases of the radiation waves such that the radiation waves accumulate to form the beam. An amount of incoherence of the beam is based on randomization of the phases.

Abstract: An apparatus for and method of cleaning a surface of a support structure in a lithographic system in which a cleaning substrate has at least one motor which causes the cleaning substrate to move laterally across the surface. The cleaning substrate may be provided with a power supply mounted on the cleaning substrate and selectably electrically connectable to the motor.

Abstract: A patterning device alignment system including a multipath sensory array including a first collimating light path and one or more other light paths, a first detector positioned at a first end of the first collimating light path, and a second detector positioned at a first end of the one or more other light paths, the first detector configured to receive a reflected illumination beam from an illuminated patterning device and calculate a tilt parameter of the patterning device, and the second detector configured to receive a second reflected illumination beam from a beam splitter and calculate an X-Y planar location position and a rotation position of the patterning device.