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Wack, CA

Dan Wack, Los Altos, CA US

Patent application numberDescriptionPublished
20090291513OVERLAY MARKS, METHODS OF OVERLAY MARK DESIGN AND METHODS OF OVERLAY MEASUREMENTS - An overlay mark for determining the relative shift between two or more successive layers of a substrate and methods for using such overlay mark are disclosed. In one embodiment, the overlay mark includes at least one test pattern for determining the relative shift between a first and a second layer of the substrate in a first direction. The test pattern includes a first set of working zones and a second set of working zones. The first set of working zones are disposed on a first layer of the substrate and have at least two working zones diagonally opposed and spatially offset relative to one another. The second set of working zones are disposed on a second layer of the substrate and have at least two working zones diagonally opposed and spatially offset relative to one another. The first set of working zones are generally angled relative to the second set of working zones thus forming an “X” shaped test pattern.11-26-2009
20100091284APPARATUS AND METHODS FOR DETECTING OVERLAY ERRORS USING SCATTEROMETRY - Disclosed are techniques, apparatus, and targets for determining overlay error between two layers of a sample. A plurality of targets is provided. Each target includes a portion of the first and second structures and each is designed to have an offset between its first and second structure portions. The targets are illuminated with electromagnetic radiation to thereby obtain spectra from each target at a −104-15-2010
20100235114SYSTEMS AND METHODS FOR DETERMINING ONE OR MORE CHARACTERISTICS OF A SPECIMEN USING RADIATION IN THE TERAHERTZ RANGE - Systems and methods for determining one or more characteristics of a specimen using radiation in the terahertz range are provided. One system includes an illumination subsystem configured to illuminate the specimen with radiation. The system also includes a detection subsystem configured to detect radiation propagating from the specimen in response to illumination of the specimen and to generate output responsive to the detected radiation. The detected radiation includes radiation in the terahertz range. In addition, the system includes a processor configured to determine the one or more characteristics of the specimen using the output.09-16-2010
20100271621METHODS AND SYSTEMS FOR DETERMINING A CRITICAL DIMENSION AND OVERLAY OF A SPECIMEN - Methods and systems for monitoring semiconductor fabrication processes are provided. A system may include a stage configured to support a specimen and coupled to a measurement device. The measurement device may include an illumination system and a detection system. The illumination system and the detection system may be configured such that the system may be configured to determine multiple properties of the specimen. For example, the system may be configured to determine multiple properties of a specimen including: but not limited to, critical dimension and overlay misregistration; defects and thin film characteristics; critical dimension and defects; critical dimension and thin film characteristics; critical dimension, thin film characteristics and defects; macro defects and micro defects; flatness, thin film characteristics and defects; overlay misregistration and flatness; an implant characteristic and defects; and adhesion and thickness. In this manner, a measurement device may perform multiple optical and/or non-optical metrology and/or inspection techniques.10-28-2010
20100279213METHODS AND SYSTEMS FOR CONTROLLING VARIATION IN DIMENSIONS OF PATTERNED FEATURES ACROSS A WAFER - Methods and systems for controlling variation in dimensions of patterned features across a wafer are provided. One method includes measuring a characteristic of a latent image formed in a resist at more than one location across a wafer during a lithography process. The method also includes altering a parameter of the lithography process in response to the characteristic to reduce variation in dimensions of patterned features formed across the wafer by the lithography process. Altering the parameter compensates for non-time varying spatial variation in a temperature to which the wafer is exposed during a post exposure bake step of the lithography process and an additional variation in the post exposure bake step.11-04-2010

Patent applications by Dan Wack, Los Altos, CA US

Daniel C. Wack, Los Altos Hills, CA US

Patent application numberDescriptionPublished
20110027919Measurement and control of strained devices - A method that includes measuring stress on at least one of a monitor substrate, a production substrate, and a proxy device on a production substrate to produce stress data, measuring shape on at least one of a proxy device on a production substrate and a production device on a production substrate to produce shape data, and inputting the stress data and the shape data into an elastic deformation calculation to determine a stress value for a production device.02-03-2011

Daniel C. Wack, Los Altos, CA US

Patent application numberDescriptionPublished
20090135416Parametric Profiling Using Optical Spectroscopic Systems - A gallery of seed profiles is constructed and the initial parameter values associated with the profiles are selected using manufacturing process knowledge of semiconductor devices. Manufacturing process knowledge may also be used to select the best seed profile and the best set of initial parameter values as the starting point of an optimization process whereby data associated with parameter values of the profile predicted by a model is compared to measured data in order to arrive at values of the parameters. Film layers over or under the periodic structure may also be taken into account. Different radiation parameters such as the reflectivities R05-28-2009
20090190141SYSTEM FOR MEASURING A SAMPLE WITH A LAYER CONTAINING A PERIODIC DIFFRACTING STRUCTURE - To measure the critical dimensions and other parameters of a one- or two-dimensional diffracting structure of a film, the calculation may be simplified by first performing a measurement of the thickness of the film, employing a film model that does not vary the critical dimension or parameters related to other characteristics of the structure. The thickness of the film may be estimated using the film model sufficiently accurately so that such estimate may be employed to simplify the structure model for deriving the critical dimension and other parameters related to the two-dimensional diffracting structure.07-30-2009
20090195779SYSTEM FOR SCATTEROMETRIC MEASUREMENTS AND APPLICATIONS - Instead of constructing a full multi-dimensional look-up-table as a model to find the critical dimension or other parameters in scatterometry, regression or other optimized estimation methods are employed starting from a “best guess” value of the parameter. Eigenvalues of models that are precalculated may be stored and reused later for other structures having certain common characteristics to save time. The scatterometric data that is used to find the value of the one or more parameter can be limited to those at wavelengths that are less sensitive to the underlying film characteristics. A model for a three-dimensional grating may be constructed by slicing a representative structure into a stack of slabs and creating an array of rectangular blocks to approximate each slab. One dimensional boundary problems may be solved for each block which are then matched to find a two-dimensional solution for the slab. A three-dimensional solution can then be constructed from the two-dimensional solutions for the slabs to yield the diffraction efficiencies of the three-dimensional grating. This model can then be used for finding the one or more parameters of the diffracting structure in scatterometry. Line roughness of a surface can be measured by directing a polarized incident beam in an incident plane normal to the line grating and measuring the cross-polarization coefficient. The value of the one or more parameters may then be supplied to a stepper or etcher to adjust a lithographic or etching process.08-06-2009

Patent applications by Daniel C. Wack, Los Altos, CA US