Patents Assigned to SVG Lithography Systems, Inc.
  • Patent number: 6486940
    Abstract: A catadioptric projection optical system for use in photolithography used in manufacturing semiconductors having a quarter waveplate following a reticle and multiple aspheric surfaces and calcium fluoride lens elements. A quarter waveplate following the reticle eliminates asymmetry in reticle diffraction caused by polarized illumination. The use of additional aspheric surfaces reduces the number of lens elements and aids in reducing aberrations. Calcium fluoride elements are used in the lens group adjacent the wafer to help minimize compaction. In one embodiment, only calcium fluoride material is used. The present invention provides a projection optics system having a numerical aperture of 0.75 for use with wavelengths in the 248, 193, and 157 nanometer range. The object and image locations are separated by a predetermined distance, making possible retrofitting of older optical systems.
    Type: Grant
    Filed: July 21, 2000
    Date of Patent: November 26, 2002
    Assignee: SVG Lithography Systems, Inc.
    Inventor: David M. Williamson
  • Patent number: 6469793
    Abstract: An alignment sensor having a fixed reference grating and a movable wafer grating receiving electromagnetic radiation from a coherent illumination source. The illumination source is split into two beams by a beamsplitter. One beam is directed to a fixed reference grating and the diffracted orders are collected. The other beam from the beamsplitter is directed to a movable wafer grating. The diffracted orders from the movable wafer grating are collected and caused to interfere with the diffracted orders from the fixed reference grating, causing a phase shift indicative of the wafer movement or misalignment with respect to the fixed reference grating. Multiple channels having discrete wavelengths or colors are used to optimize detection and alignment irrespective of wafer processing variables. A polarization fixture on the illumination source and a central polarizing portion on the beamsplitter is used to provide contrast optimization, or alternately a latent image metrology mode.
    Type: Grant
    Filed: August 10, 1999
    Date of Patent: October 22, 2002
    Assignee: SVG Lithography Systems, Inc.
    Inventor: Stuart T. Stanton
  • Patent number: 6445439
    Abstract: A thermal management device for use with a photolithographic apparatus or tool substantially reducing thermal distortion in a reticle. Planar cooling elements are placed adjacent a reticle being illuminated with extreme ultraviolet, EUV, electromagnetic radiation. A heating element provides heat prior to exposure of the reticle by the EUV electromagnetic radiation and the system is in thermal equilibrium. Upon exposure of the EUV electromagnetic radiation, absorption by the reticle causes heat. The heating element is controlled to reduce the heat provided so the extra heat load generated in the reticle during exposure due to absorption of the EUW electromagnetic radiation is compensated for. The reticle therefore experiences no net heat or thermal energy change, and therefore eliminates or substantially reduces both expansion and thermal gradients in the reticle.
    Type: Grant
    Filed: December 27, 1999
    Date of Patent: September 3, 2002
    Assignee: SVG Lithography Systems, Inc.
    Inventor: Andrew W. McCullough
  • Patent number: 6444372
    Abstract: A reticle or mask for use in projecting a circuit pattern on a photosensitive resist covered wafer having a transparent substrate with a reflective or dielectric layer thereon. An opaque or blocking layer, for example chrome or chromium, is placed over the reflective layer. The opaque layer then has a predetermined circuit pattern etched therein. In one embodiment, the opaque layer and the reflective layer are the same size. In another embodiment, the opaque layer has a size larger than the reflective layer. This permits the opaque layer to be adjacent the substrate which is advantageous when projection optics having a high numerical aperture are used. The reticle of the present invention has particular advantage when high throughput photolithographic tools are used having an illumination source of high energy flux with a wavelength of between 157 nanometers and 365 nanometers. Illumination in this wavelength range has considerable absorption in chrome, a common opaque material used in reticles.
    Type: Grant
    Filed: October 25, 1999
    Date of Patent: September 3, 2002
    Assignee: SVG Lithography Systems, Inc.
    Inventor: Andrew W. McCullough
  • Patent number: 6425280
    Abstract: A jig for aligning a wafer-handling system in a calibration location, such as a wafer pickup-dismount location, with respect to a wafer-processing tool. The jig comprises an alignment fixture adapted to be repeatably mounted on the tool and having one or more edge stops. The jig may further comprise an edge-to-center locator adapted to be mounted on the alignment fixture. The edge-to-center locator has a peripheral edge and a center marker that identifies the precise center of the calibration location when the edge-to-center locator edge is positioned in contact with the edge stop or stops. An alignment method for use of the jig is also disclosed.
    Type: Grant
    Filed: July 30, 1999
    Date of Patent: July 30, 2002
    Assignees: International Business Machines Corporation, SVG Lithography Systems, Inc.
    Inventors: Dennis B. Ames, John J. Bacich
  • Patent number: 6360012
    Abstract: Wavefront information for an optical system is calculated based on the intensity of an image of a plurality of gratings having different periods and orientations taken from at least two different planes a predetermined distance apart. The image of a plurality of gratings having different spatial frequencies or periods and orientations, the location of which are precisely known, are imaged in a nominal focal plane of the optical system, and, preferably, in two additional planes displaced a predetermined distance from the nominal focal plane. The phase shift, if any, from a fundamental frequency of the image intensity, is determined based on the known location of the grating and the grating image intensity. The grating image intensity is detected and measured in a first detection plane in a nominal focal plane and in a second detection plane a predetermined distance from the nominal focal plane. From these measurements wavefront information is calculated.
    Type: Grant
    Filed: June 25, 1999
    Date of Patent: March 19, 2002
    Assignee: SVG Lithography Systems, Inc.
    Inventor: Justin L. Kreuzer
  • Patent number: 6292255
    Abstract: In a scanning photolithographic device used in the manufacture of semiconductors, a method and apparatus for varying the exposure dose as a function of distance in the scan direction compensating for the signature of the photolithographic device for reducing linewidth variation in the scan direction. The linewidth in the scan direction may vary for a particular device or tool for a variety of reasons. This variation or signature is used in combination with a photosensitive resist response function to vary the exposure dose as a function of distance in a scan direction, substantially reducing the linewidth variation. A dose control varies the exposure dose as a function of distance in a scan direction to correct linewidth variations caused by characteristics of the photolithographic system. Linewidth variations as a function of distance in the direction of scan are substantially reduced, resulting in more consistent and improved feature or element sizes.
    Type: Grant
    Filed: January 15, 1999
    Date of Patent: September 18, 2001
    Assignee: SVG Lithography Systems, Inc.
    Inventor: Andrew W. McCullough
  • Patent number: 6259513
    Abstract: An illumination system used in photolithography for the manufacture of semiconductors having an array optical element with different illumination regions matched to different geometric pattern regions on a reticle. The array optical element may be a filter, diffractive optical element, or microlens array having illumination regions producing different types of illumination properties or characteristics such as quadrupole, annular, or top hat among others. Each of the illumination regions are matched or correspond to a respective pattern region on the reticle to provide optimized exposure of a photosensitive resist covered wafer. The optical element of the present invention may be used to tailor a conventional illumination system to the unique characteristics of a particular reticle. Additionally, imperfections in the optics of a photolithographic system can be compensated for by the optical element.
    Type: Grant
    Filed: February 11, 1997
    Date of Patent: July 10, 2001
    Assignee: SVG Lithography Systems, Inc.
    Inventors: Gregg Gallatin, Andrew W. McCullough
  • Patent number: 6195201
    Abstract: An illumination source or condenser used to project the image of a reticle onto a photosensitive substrate used in photolithography having a first reflective fly's eye, faceted mirror, or mirror array with predeterminedly positioned facets or elements and a second reflective fly's eye, faceted mirror, or mirror array having predeterminedly positioned facets or elements for creating a desired radiant intensity, pupil fill, or angular distribution. A source of extreme ultraviolet electromagnetic radiation is provided to a first fly's eye or mirror array with arcuate shaped facets or elements. The arcuate shaped facets or elements are positioned to create an image of the source at corresponding facet in a second reflective fly's eye or mirror array. A desired shape and irradiance together with a desired radiant intensity, pupil fill, or angular distribution is obtained. An arcuate illumination field or image is formed with high efficiency in a compact package.
    Type: Grant
    Filed: January 27, 1999
    Date of Patent: February 27, 2001
    Assignee: SVG Lithography Systems, Inc.
    Inventors: Donald G. Koch, James P. McGuire, Joseph M. Kunick
  • Patent number: 6097474
    Abstract: Blades pivotally attached together linked to push rods and inserted into an illumination field, energy or flux. The blades extend longitudinally along the length of a rectangular illumination field or slit used to image a reticle onto a photosensitive substrate. The blades controllably adjust the width of the rectangular illumination field to modify the illumination intensity or energy provided to a photosensitive substrate. The illumination field is scanned across the photosensitive substrate to expose it with the image of a reticle. The blades are dynamically controlled during the scanning exposure to adjust the illumination intensity or energy in a predetermined way. The resulting selective change in exposure dose corrects local area of line width variance. Various errors in pattern reproduction using a photolithographic system are relatively easily corrected. This is particularly advantageous in a scanning lithography system used in the manufacture of semiconductors.
    Type: Grant
    Filed: September 8, 1999
    Date of Patent: August 1, 2000
    Assignee: SVG Lithography Systems, Inc.
    Inventors: Andrew W. McCullough, Pradeep K. Govil, Daniel N. Galburt, David Callan
  • Patent number: 6013401
    Abstract: Blades pivotally attached together linked to push rods and inserted into an illumination field, energy or flux. The blades extend longitudinally along the length of a rectangular illumination field or slit used to image a reticle onto a photosensitive substrate. The blades controllably adjust the width of the rectangular illumination field to modify the illumination intensity or energy provided to a photosensitive substrate. The illumination field is scanned across the photosensitive substrate to expose it with the image of a reticle. The blades are dynamically controlled during the scanning exposure to adjust the illumination intensity or energy in a predetermined way. The resulting selective change in exposure dose corrects local area of line width variance. Various errors in pattern reproduction using a photolithographic system are relatively easily corrected. This is particularly advantageous in a scanning lithography system used in the manufacture of semiconductors.
    Type: Grant
    Filed: January 15, 1999
    Date of Patent: January 11, 2000
    Assignee: SVG Lithography Systems, Inc.
    Inventors: Andrew W. McCullough, Pradeep K. Govil, Daniel N. Galburt, David Callan
  • Patent number: 5973764
    Abstract: A vacuum manifold having a rectangular opening with vacuum access bores connected into the rectangular opening for an illumination field to be projected there through. A vacuum manifold is placed between a photosensitive resist covered wafer and a lens element in a photolithographic tool. The relatively high illumination energy in an illumination field used for projecting an image of a reticle onto a photosensitive resist covered wafer often results in ablated, evaporated, and effused material being coated on the lens element. The vacuum manifold placed between the lens element and the photosensitive resist covered wafer creates an airflow for removing debris or contamination preventing coating of the lens surface. This prevents image quality from degradation over time, as well as reduces downtime needed for cleaning or maintenance of the photolithographic tool.
    Type: Grant
    Filed: June 19, 1997
    Date of Patent: October 26, 1999
    Assignee: SVG Lithography Systems, Inc.
    Inventors: Andrew W. McCullough, Sean Olson
  • Patent number: 5966202
    Abstract: Blades pivotally attached together linked to push rods and inserted into an illumination energy or flux. The blades extend longitudinally along the length of a rectangular illumination field or slit used to image a reticle onto a photosensitive substrate. The push rods are coupled to a flexure or link pivotally connected to each end of a substantially rectangular blade. The corners of the rectangular blades have a radius providing a smooth transition between blades. A frame holds the push rods in place as the blades are moved into and out of the illumination energy or flux. The push rods may be adjusted by a screw or other equivalent devices or methods. The lateral or sideways forces resulting from the movement of the blades is compensated for by the flexures or links resulting in less stress being placed on the blades. Slots placed at pivot points in the blades may also be used to facilitate movement of the blades.
    Type: Grant
    Filed: March 31, 1997
    Date of Patent: October 12, 1999
    Assignee: SVG Lithography Systems, Inc.
    Inventor: Andrew W. McCullough
  • Patent number: 5966216
    Abstract: An on-axis through the lens optical alignment system for use in semiconductor manufacturing using step and scan photolithographic techniques. An optical alignment system uses a partially common path with the projection optics (16) optical axis (38) in order to detect alignment targets on a wafer (10) and a mask (20). The relative position of the mask (20) and wafer (10) is detected during a single simultaneous scan, and the mask (20) and wafer (10) are resultantly aligned. This provides advantages over prior art multiple channel off-axis through the lens alignment systems and single channel non-through the lens alignment systems. A detailed optical apparatus (60) is disclosed.
    Type: Grant
    Filed: February 14, 1997
    Date of Patent: October 12, 1999
    Assignee: SVG Lithography Systems, Inc.
    Inventors: Daniel N. Galburt, David M. Williamson
  • Patent number: 5966215
    Abstract: An alignment system for use in semiconductor manufacturing that matches pairs of like edges of alignment marks. Grating type alignment marks are illuminated by a predetermined illumination pattern with the reflected and/or scattered electromagnetic radiation collected by a detector. Like edges are selected from the collected electromagnetic radiation and matched. A signal analyzer analyses the matched like edges and obtains alignment information. The matching of like edges results in relatively process insensitive detection of wafer alignment marks. The distance between like edges is substantially less effected by wafer processing. Wafer alignment marks can thereby be more accurately detected, resulting in improved positioning and alignment accuracies. This improves and advances the technology use to manufacture semiconductor devices.
    Type: Grant
    Filed: April 13, 1999
    Date of Patent: October 12, 1999
    Assignee: SVG Lithography Systems, Inc.
    Inventors: Louis Markoya, Joseph Lyons
  • Patent number: 5956192
    Abstract: An all reflective ring field projection optic system for use in scanning photolithography used in the manufacture of semiconductor wafers. The projection optics are designed for wavelengths in the extreme ultraviolet ranging from 11 to 13 nm to provide an arcuate image field for a reduction step and scan photolithography system. A sequence or configuration of mirrors from the long conjugate end to the short conjugate end consists of a convex, concave, convex, and concave mirror with an aperture stop being formed at or near the second convex mirror. This sequence of mirror powers provides a relatively large image field size while maintaining a relatively compact reticle wafer distance of less than 900 mm. The projection optics form an instantaneous annual field of up to 50 mm.times.2 mm at the wafer, permitting scanning to cover a field on a wafer of at least 50 mm.times.50 mm, greatly increasing throughput. The optical projection system can print features as small as 0.05 microns.
    Type: Grant
    Filed: September 18, 1997
    Date of Patent: September 21, 1999
    Assignee: SVG Lithography Systems, Inc.
    Inventor: David M. Williamson
  • Patent number: 5920396
    Abstract: An alignment system for use in semiconductor manufacturing that matches pairs of like edges of alignment marks. Grating type alignment marks are illuminated by a predetermined illumination pattern with the reflected and/or scattered electromagnetic radiation collected by a detector. Like edges are selected from the collected electromagnetic radiation and matched. A signal analyzer analyses the matched like edges and obtains alignment information. The matching of like edges results in relatively process insensitive detection of wafer alignment marks. The distance between like edges is substantially less effected by wafer processing. Wafer alignment marks can thereby be more accurately detected, resulting in improved positioning and alignment accuracies. This improves and advances the technology use to manufacture semiconductor devices.
    Type: Grant
    Filed: October 16, 1996
    Date of Patent: July 6, 1999
    Assignee: SVG Lithography Systems, Inc.
    Inventors: Louis Markoya, Joseph Lyons
  • Patent number: 5896188
    Abstract: An illumination system for a scanning lithography system used in the manufacture of semiconductor devices having a multiplex array or multi-image array resulting in pattern noise that is reduced by a spatially frequency modulated multiplex array or frequency modulating the pulse rate of a pulsed laser source. A pulsed laser source is used to illuminate a reticle containing a pattern thereon to be reproduced onto a semiconductor. An illumination system using a multiplex array or multi-image array to obtain macro uniformity of an illumination slot or field introduces micro non-uniformity that results in undesirable pattern noise or fixed pattern noise resulting in undesirable imaging properties. The undesirable effects of the pattern noise are eliminated or substantially reduced by spatially modulating the multiplex array in a scanning direction so that the periodic pattern has a linear magnification dependent on position. In another embodiment the pulse rate of the pulsed laser source is frequency modulated.
    Type: Grant
    Filed: April 10, 1997
    Date of Patent: April 20, 1999
    Assignee: SVG Lithography Systems, Inc.
    Inventor: Andrew W. McCullough
  • Patent number: 5895737
    Abstract: Blades pivotally attached together linked to push rods and inserted into an illumination energy or flux. The blades extend longitudinally along the length of a rectangular illumination field or slit used to image a reticle onto a photosensitive substrate. The push rods are coupled to a flexure or link pivotally connected to each end of a substantially rectangular blade. The corners of the rectangular blades have a radius providing a smooth transition between blades. A frame holds the push rods in place as the blades are moved into and out of the illumination energy or flux. The push rods may be adjusted by a screw or other equivalent devices or methods. The lateral or sideways forces resulting from the movement of the blades is compensated for by the flexures or links resulting in less stress being placed on the blades. Slots placed at pivot points in the blades may also be used to facilitate movement of the blades.
    Type: Grant
    Filed: February 12, 1998
    Date of Patent: April 20, 1999
    Assignee: SVG Lithography Systems, Inc.
    Inventors: Andrew W. McCullough, Pradeep K. Govil
  • Patent number: 5818575
    Abstract: Two detectors are effectively positioned at a predetermined lateral position in a rectangular illumination field at a wafer plane. The ratio of the signals from the two detectors is calculated. This ratio is indicative of the quality of the illumination field and any lamp instability which may effect the illumination field, and therefore image quality. In a photolithographic device, a short arc mercury xenon lamp provides illumination for projecting the image of a reticle onto a photosensitive resist covered substrate or wafer. The desired illumination intensity profile is sensitive to lamp instability. This instability may alter the desired illumination intensity profile which may adversely effect image quality, and therefore the resulting product. The ratio of the signals received from predetermined locations laterally along the illumination intensity profile improves the detection of unstable lamps.
    Type: Grant
    Filed: April 30, 1997
    Date of Patent: October 6, 1998
    Assignee: SVG Lithography Systems, Inc.
    Inventor: Michael A. Creighton