Patents Assigned to K-Technologies, Inc.
-
Patent number: 7525672Abstract: Methods and apparatus for optical characterization based on symmetry-reduced 2-D RCWA calculations are provided. The invention is applicable to gratings having a grating reflection symmetry plane. A sample can be illuminated at normal incidence or at a non-zero angle of incidence such that the plane of incidence is parallel to or identical with the symmetry plane. The diffracted field components are either symmetric or anti-symmetric with respect to the grating symmetry plane. This symmetry is exploited to provide a symmetry-reduced 2-D RCWA having reduced matrix dimension (by about a factor of two) that is mathematically equivalent to a conventional 2-D RCWA. For normal incidence on a grating having two reflection symmetry planes, a symmetry-reduced 2-D RCWA having reduced matrix dimension (by about a factor of four) is provided. This normal incidence RCWA can be used to approximately characterize a sample illuminated at non-normal incidence.Type: GrantFiled: December 16, 2005Date of Patent: April 28, 2009Assignee: n&k Technology, Inc.Inventors: Shuqiang Chen, Guoguang Li
-
Patent number: 7505147Abstract: Improved computation of Fourier coefficients for modeling of 2-D grating diffraction is provided. Let f(x,y) be defined in a region ?. Typically, f(x,y) is piecewise constant (since it is a grating permittivity or inverse permittivity) and takes on various constant values in several domains in ?. Let D be one of these domains, having a general shape. According to the invention, D is approximated as a set of trapezoids, and f(x,y) is taken to have a constant value within each of the trapezoids. Since the Fourier coefficient of a constant defined on a trapezoidal region can be analytically evaluated, an analytic approximation to the Fourier coefficient of f(x,y) on D is provided by summing the contributions from each trapezoid.Type: GrantFiled: May 26, 2006Date of Patent: March 17, 2009Assignee: n&k Technology, Inc.Inventors: Shuqiang Chen, Guoguang Li
-
Patent number: 7397554Abstract: An apparatus and method for examining features of a planar, disk-shaped samples on a stage that holdings the sample and has an X-drive, a Y-drive and a ?-drive for rotating the stage about a center of rotation defined in the stage coordinates. The sample is placed on the stage such that the center of the sample is substantially aligned with the center of rotation and a measurement assembly is located above the sample to examine the features optically. A scheduling module coordinates the X-drive, the Y-drive and the ?-drive with the measurement assembly such that the sample is examined in an even number n of angular sectors defined by a sector angle ? that is the same for each sector. Specifically, the sector angle ? is defined in terms of n as follows: ? = 360 ? ° n , where n=4m and m is an integer, such that a multiple of sector angle ? always includes angles 90° and 180°.Type: GrantFiled: January 4, 2006Date of Patent: July 8, 2008Assignee: n&k Technology, Inc.Inventors: Guoguang Li, Marc Aho
-
Patent number: 7397030Abstract: This invention relates to an apparatus and method for integrated measurement of a sample that has miniature features. The apparatus has an optical measuring unit for illuminating the sample with a global test radiation over an optical test region and obtaining an optical response, such as scattered or transmitted radiation from the optical test region. In addition, the apparatus has a local measuring unit for making a nanometer scale measurement of a local material parameter ? of the sample. The local parameter ? is determined with a mechanical, optical, magnetic, electric or other physical measurement performed in the nanometer range with a scanning probe tip at a test location lying within the optical test region. The material parameter ? is selected such that it is substantially constant or uniform over the illuminated area.Type: GrantFiled: June 1, 2006Date of Patent: July 8, 2008Assignee: n&k Technology, Inc.Inventors: Mehdi Balooch, Abdul Rahim Forouhi
-
Patent number: 7391524Abstract: A system and a method for optical characterization of a symmetric grating illuminated at off-normal incident angle are provided, where the plane of incidence is parallel to the grating lines. In this case corresponding positive and negative diffraction orders have the same intensity and phase. Several approaches for exploiting this symmetry are given. The first approach is a symmetric rigorous coupled wave analysis (SRCWA) adapted to the symmetric case, which accounts for N positive and N negative diffraction orders with M=N+1 space harmonics, without approximation. Various approximation methods are also given. Approximate versions of the RCWA (or SRCWA) can be developed by neglecting polarization coupling for small angles of incidence. A normal incident angle calculation can be used to approximate a situation with a small angle of incidence. Refinements to this approximation include revision of grating depth or refractive indices to improve accuracy.Type: GrantFiled: September 13, 2004Date of Patent: June 24, 2008Assignee: n&k Technology, Inc.Inventors: Shuqiang Chen, Guoguang Li
-
Patent number: 7349103Abstract: An apparatus and method for examining features of a sample with a broadband beam of light obtained from a long-wavelength source that may include two distinct emitters that emit a long-wavelength radiation and a short-wavelength source that emits a short-wavelength radiation. A passage is positioned between the sources and a reflective beam combining optics is provided for shaping the long-wavelength radiation to enter the short-wavelength source via the passage and also for shaping the short-wavelength radiation that exits through the passage and propagates toward the long-wavelength source. The reflective beam combining optics shape the short-wavelength radiation such that it re-enters the short-wavelength source via the passage and is combined with the long-wavelength radiation into the broadband beam that exits the short-wavelength source.Type: GrantFiled: October 31, 2005Date of Patent: March 25, 2008Assignee: n&k Technology, Inc.Inventors: Mehdi Balooch, Marc Aho, Homan Amin, Abdul Rahim Forouhi, Phillip Walsh, Guoguang Li
-
Patent number: 7330256Abstract: A system uses reflectance spectrophotometry to characterize a sample having any number of structures. The system uses toroidal mirrors that are shaped in such a way that the angle of reflectance off of the target is small. The small angle of reflectance may allow for simplification of calculations and can result in a faster processing time. In addition, a more accurate measurement can be achieved when the reflected beam is close to normal.Type: GrantFiled: May 16, 2005Date of Patent: February 12, 2008Assignee: n&k Technology, Inc.Inventors: Marc Aho, Abdul Rahim Forouhi
-
Patent number: 7327457Abstract: An apparatus and method for optically characterizing the reflection and transmission properties of a sample with a beam of light having a small diameter on a surface of the sample over a broadband of wavelengths, from 190 nm to 1100 nm. Reflective optical components, including off-axis parabolic mirrors with a collimated incident or reflected broadband beam of light, minimize non-chromatic aberration. Angles of incidence and reflection from optical components and the sample are kept substantially near normal to the optical components and the sample to minimize changes in the polarization of the beam of light. The apparatus and method further disclose an optical light path that can be focused by adjusting the position of an off-axis parabolic mirror and a planar mirror.Type: GrantFiled: December 19, 2003Date of Patent: February 5, 2008Assignee: n&k Technology, Inc.Inventors: Ray Hebert, Marc Aho, Abdul Rahim Forouhi
-
Patent number: 7290978Abstract: A flipper for rotating and positioning a photomask in two flip orientations includes a flip unit rotatably held in a base. The flip unit includes a flip frame in which clamps are preferably spring loaded guided such that the clamps are oppositely and laterally displaceable between engaged positions and parking positions. A stepper motor rotates the flip unit between two flip orientations and positions the flip unit such that opposite inspection sides of the work piece are alternately oriented with respect to a single inspection direction. The flipper may be placed on or adjacent to a stage system of an inspection device. A robotically actuated effector may access the flipper for loading and unloading the work piece. In combination with an effector operating without lift motion, the clamps may feature wedge lift faces to lift the work piece off the effector during their actuation into engaged position.Type: GrantFiled: June 9, 2004Date of Patent: November 6, 2007Assignee: n&k Technology Inc.Inventor: Daniel Tran
-
Patent number: 7289214Abstract: A system and method for optical offset measurement is provided. An offset between two grating layers in a compound grating is measured by illuminating the gratings with light having a plane of incidence that is neither parallel with nor perpendicular to the grating lines. This non-symmetrical optical illumination allows determination of the sign and magnitude of the offset. Two measurements are performed at azimuthal angles separated by 180°, and a difference of these measurements is calculated. Measurement of this difference allows determination of the offset (e.g., with a calibration curve). Alternatively, two compound gratings having a predetermined non-zero offset difference can be employed. This arrangement permits determination of the offsets without the need for a calibration curve (or for additional compound gratings), based on a linear approximation.Type: GrantFiled: November 23, 2004Date of Patent: October 30, 2007Assignee: n&k Technology, Inc.Inventors: Guoguang Li, Shuqiang Chen, Abdul Rahim Forouhi
-
Patent number: 7253909Abstract: An apparatus and method for determining a physical parameter of features on a substrate by illuminating the substrate with an incident light covering an incident wavelength range ??, e.g., from 190 nm to 1000 nm, where the substrate is at least semi-transparent. A response light received from the substrate and the feature is measured to obtain a response spectrum of the response light. Further, a complex-valued response due to the feature and the substrate is computed and both the response spectrum and the complex-valued response are used in determining the physical parameter. A direct approximate phase measurement is provided when the response light is transmitted light.Type: GrantFiled: January 3, 2005Date of Patent: August 7, 2007Assignee: n&k Technology, Inc.Inventors: Guoguang Li, Phillip Walsh, Shuqiang Chen, Abdul Rahim Forouhi
-
Patent number: 7248364Abstract: An apparatus and method for optically characterizing the reflection and transmission properties of a sample with a beam of light having a small diameter on a surface of the sample over a broadband of wavelengths, from 190 nm to 1100 nm. Reflective optical components, including off-axis parabolic mirrors with a collimated incident or reflected broadband beam of light, minimize non-chromatic aberration. The apparatus and method further disclose an optical light path that can be focused by adjusting the position of an off-axis parabolic mirror and a planar mirror.Type: GrantFiled: December 19, 2003Date of Patent: July 24, 2007Assignee: n&k Technology, Inc.Inventors: Ray Hebert, Marc Aho, Abdul Rahim Forouhi
-
Patent number: 7212293Abstract: Optical characterization of lateral features of a pattern is provided. A plane-wave optical response is calculated for each feature. At least one of these plane-wave responses is calculated from an effective optical property (e.g., a waveguide modal refractive index). Such effective optical properties depend on feature geometry and on intrinsic material optical properties. The plane-wave responses for each feature are combined to generate a modeled pattern response. By fitting the modeled pattern response to a corresponding measured pattern response, estimates for pattern feature parameters are obtained. The use of an effective optical property improves model accuracy, especially for features having a size on the order of a wavelength or less, without significantly increasing computation time.Type: GrantFiled: June 1, 2004Date of Patent: May 1, 2007Assignee: n&k Technology, Inc.Inventors: Guoguang Li, Shuqiang Chen, Phillip Walsh
-
Patent number: 7044476Abstract: A compact pinlifter assembly is fitted in a substantially enclosed cavity within a wafer chuck such that an overall outside shape of the wafer chuck remains highly unaffected. The pinlifter assembly includes wedge guides providing a movement path in a wedge angle relative to the wafer holding face. A pin actuator is driven along the wedge guides transforming its movement along the wedge guides into a vertical movement of the lifting pins perpendicularly sliding between the cavity and the wafer holding face. The combination of wedge guides and pin actuator takes advantage of the relatively large lateral dimensions of the wafer chuck to move the pin actuator between end positions that are in a distance multiple of the pin lifters movement. Due to the wedge angle, the actuators comparatively large scale movement is transformed in a highly precise, smooth and balanced movement of the pin lifters.Type: GrantFiled: November 25, 2003Date of Patent: May 16, 2006Assignee: N&K Technology, Inc.Inventor: Daniel Tran
-
Patent number: 6891628Abstract: An apparatus and method for determining a physical parameter of features on a substrate by illuminating the substrate with an incident light covering an incident wavelength range ??, e.g., from 190 nm to 1000 nm, where the substrate is at least semi-transparent. A response light received from the substrate and the feature is measured to obtain a response spectrum of the response light. Further, a complex-valued response due to the feature and the substrate is computed and both the response spectrum and the complex-valued response are used in determining the physical parameter. The response light is reflected light, transmitted light or a combination of the two. The complex-valued response typically includes a complex reflectance amplitude, a complex transmittance amplitude or both. The apparatus and method take into account the effects of vertical and lateral coherence length and are well suited for examining adjacent features.Type: GrantFiled: June 25, 2003Date of Patent: May 10, 2005Assignee: n & k Technology, Inc.Inventors: Guoguang Li, Phillip Walsh, Abdul R. Forouhi
-
Patent number: 6825933Abstract: Embodied in a reflectance system capable of providing high resolution, repeatable, efficient, and accurate reflectance measurements of a silicon or silicon-oxide wafer at all wavelengths, the present invention, including an inventive and useful software tool with user interface, provides a solution to monitor non-destructively low dose ion implantation without potentially suffering from undesirable annealing effect. The computer-implemented method disclosed herein determines a reflectance change index that correlates to the ion dose. The reflectance change index is determined based on an absolute value of reflectance changes over the entire measured spectra. The reflectance changes are determined based on non-implanted and implanted reflectance measurements of the wafer respectively obtained at each of the wavelengths.Type: GrantFiled: June 7, 2002Date of Patent: November 30, 2004Assignee: N&K Technology, Inc.Inventors: Jeff Roberts, Abdul Rahim Forouhi
-
Patent number: 6811370Abstract: An apparatus for handling and positioning wafers or other flat objects. The apparatus has an XY stage with an X-drive and a Y-drive, and a bed attached to the XY stage. A chuck (e.g. a vacuum chuck) is disposed on the bed and an effector is attached to the bed. The effector can rotate about an axis of rotation extending in the Z-direction. The effector can pick up objects and place the objects onto the chuck. The effector can also pick up objects from the chuck. Preferably, the chuck has a recessed region for accommodating the effector so that the effector can be inserted under a flat object on the chuck. The X-drive or Y-drive of the XY stage provides linear motion for the effector so that the effector can pull wafers from a cassette such as used in the semiconductor industry. Alternatively, the effector is attached to a linear actuator disposed on the bed.Type: GrantFiled: December 21, 2000Date of Patent: November 2, 2004Assignee: N&K Technology, Inc.Inventor: Dale Buermann
-
Patent number: 6765676Abstract: An optical system for simultaneously compensating a source drift of a light source and a detector drift of a light detector includes a test location, a first beam path from the light source to the test location, a second beam path from the test location to the light detector. First and second beam paths are arranged to intersect at a beam crossing. A calibration sample having a known reflectivity is positioned at the test location and illuminated by a probe beam generated by the light source. A known response beam of the calibration sample is used for calibrating the light source and the detector. A reference sample is placed at the beam crossing and illuminated by the probe beam. In response, the reference sample sends a reference beam along the second path length, which is used for compensating the source and detector drift.Type: GrantFiled: August 30, 2000Date of Patent: July 20, 2004Assignee: N & K Technology, Inc.Inventor: Dale Buermann
-
Patent number: 6710865Abstract: The present invention provides a method for inferring optical parameters of a sample in a predictive spectral range by use of the known values of the optical parameters in a predetermined measurement spectral range. The method of the present invention capitalizes on the Forouhi-Bloomer dispersion equations for the optical constants n and k.Type: GrantFiled: September 14, 2001Date of Patent: March 23, 2004Assignee: N&K Technology, Inc.Inventors: Abdul Rahim Forouhi, Dale A. Harrison, Erik Maiken, John C. Lam
-
Patent number: 6676101Abstract: A horizontal-motion vibration isolation system for supporting an object in an equilibrium position relative to a base while suppressing the transmission of horizontal vibratory motion between the object and the base includes a plurality of columns, each column having a rigid member with a first end and a second end. A tilt mechanism is operatively connected to each first end of the rigid members and the object. Likewise, a tilt mechanism is operatively connected to each second end of the rigid members and the base. Each tilt mechanism exhibits a tilt rotational stiffness and the horizontal translation of the object relative to the base causes tilt rotation of the columns. The tilt rotational stiffness of the tilt mechanisms is approximately proportional to the compression load transmitted to the columns by the weight of the object, so that the horizontal natural frequency of the system is nearly insensitive to the payload weight.Type: GrantFiled: May 28, 2002Date of Patent: January 13, 2004Assignee: Minus K. Technology, Inc.Inventor: David L. Platus