Patents Assigned to Cadence Design Systems
  • Publication number: 20090144681
    Abstract: An automated debugging method and system for over-constrained circuit verification environment are described. Useful information related to circuit evaluation and/or over-constrained event is collected and provided. The information may include: clock cycles at which an over-constrained event occurs; identification of a minimum subset of constraints that will cause an over-constrained event to occur; signal ports having an associated signal that can not switch between different signal states; whether a triggering signal event has occurred during the evaluation; indicating whether constraints in the evaluation are realizable, etc. Novel approaches for detecting and obtaining the useful information also are described.
    Type: Application
    Filed: October 31, 2008
    Publication date: June 4, 2009
    Applicant: Cadence Design Systems, Inc.
    Inventors: Amir LEHAVOT, Vinaya Kumar SINGH, Joezac John ZACHARIAH, Jose BARANDIARAN, Axel Siegfried SCHERER
  • Publication number: 20090144683
    Abstract: An automated debugging method and system for over-constrained circuit verification environment are described. Useful information related to circuit evaluation and/or over-constrained event is collected and provided. The information may include: clock cycles at which an over-constrained event occurs; identification of a minimum subset of constraints that will cause an over-constrained event to occur; signal ports having an associated signal that can not switch between different signal states; whether a triggering signal event has occurred during the evaluation; indicating whether constraints in the evaluation are realizable, etc. Novel approaches for detecting and obtaining the useful information also are described.
    Type: Application
    Filed: October 31, 2008
    Publication date: June 4, 2009
    Applicant: Cadence Design Systems, Inc.
    Inventors: Amir Lehavot, Vinaya Kumar Singh, Joezac John Zachariah, Jose Barandiaran, Axel Siegfried Scherer
  • Publication number: 20090144680
    Abstract: An automated debugging method and system for over-constrained circuit verification environment are described. Useful information related to circuit evaluation and/or over-constrained event is collected and provided. The information may include: clock cycles at which an over-constrained event occurs; identification of a minimum subset of constraints that will cause an over-constrained event to occur; signal ports having an associated signal that can not switch between different signal states; whether a triggering signal event has occurred during the evaluation; indicating whether constraints in the evaluation are realizable, etc. Novel approaches for detecting and obtaining the useful information also are described.
    Type: Application
    Filed: October 31, 2008
    Publication date: June 4, 2009
    Applicant: Cadence Design Systems, Inc.
    Inventors: Amir LEHAVOT, Vinaya Kumar Singh, Joezac John Zachariah, Jose Barandiaran, Axel Siegfried Scherer
  • Patent number: 7543262
    Abstract: In a computer implemented method of device layout in an integrated circuit design an array having a plurality of cells is selected and stored in a memory of a computer. A schematic view of a plurality of interconnected circuit devices of a circuit is displayed on the computer's display. One or more of the circuit devices of the displayed schematic view are selected by a user. Responsive to the selection of each circuit device, a processing means of the computer populates an empty cell of the array in the memory of the computer with a corresponding layout instance of the circuit device, wherein each layout instance represents a physical arrangement of material(s) that form the corresponding selected circuit device.
    Type: Grant
    Filed: December 6, 2005
    Date of Patent: June 2, 2009
    Assignee: Cadence Design Systems, Inc.
    Inventors: Zhigang Wang, Elias Fallon, Regis R. Colwell
  • Patent number: 7543251
    Abstract: Some embodiments of the invention provide a method for pre-tabulating sub-networks. This method (1) generates a sub-network that performs a function, (2) generates a parameter based on this function, and (3) stores the sub-network in a storage structure based on the generated parameter. In some embodiments, the generated sub-network has several circuit elements. Also, in some embodiments, the generated sub-network performs a set of two or more functions. Some embodiments store each generated sub-network in an encoded manner. Some embodiments provide a method for producing a circuit description of a design. This method (1) selects a candidate sub-network from the design, (2) identifies an output function performed by the sub-network, (3) based on the identified output function, identifies a replacement sub-network from a storage structure that stores replacement sub-networks, and (4) replaces the selected candidate sub-network with the identified replacement sub-network in certain conditions.
    Type: Grant
    Filed: January 31, 2003
    Date of Patent: June 2, 2009
    Assignee: Cadence Design Systems, Inc.
    Inventors: Steven Teig, Asmus Hetzel
  • Patent number: 7539961
    Abstract: A system and method for modeling an IC (integrated circuit) employs a mesh model and a grid model for separating impedance effects between nearby and far-away pairs of mesh elements. Models for relating currents and voltages can be incrementally adapted from other designs or design elements in applications including mixed-signal, analog and RF (radio frequency) circuits.
    Type: Grant
    Filed: November 17, 2006
    Date of Patent: May 26, 2009
    Assignee: Cadence Design Systems, Inc.
    Inventors: Enis Aykut Dengi, Feng Ling, Ben Song, Warren Harris
  • Patent number: 7536670
    Abstract: A test mask with both verification structures and calibration structures is provided to enable the formation of an image of at least one verification structure and at least one calibration structure at a plurality of different test site locations under different dose and defocus conditions to allow the calibration structures to be measured and to obtain at least one computational model for optical proximity correction purposes.
    Type: Grant
    Filed: May 31, 2005
    Date of Patent: May 19, 2009
    Assignee: Cadence Design Systems, Inc.
    Inventors: Gökhan Perçin, Ram Ramanujam, Franz Xaver Zach
  • Patent number: 7536665
    Abstract: A mechanism is provided for the user to define a circuit design intent or strategy in the form of data that is stored with the design database. An autorouter then uses this guidance from the user to create a plan for routing the design. The user can then modify their guidance to the router until the results for the plan are acceptable. Using the planned flow, the autorouter can complete the design, creating detailed paths including etch segments and vias. Allowing such interaction with an autorouter significantly reduces the routing time and hence time-to-market.
    Type: Grant
    Filed: July 25, 2006
    Date of Patent: May 19, 2009
    Assignee: Cadence Design Systems, Inc.
    Inventors: Greg Horlick, Randall Lawson, Donald Morgan, Paul Musto, Joe Smedley, Ken Wadland, Richard Woodward, Sean Bergan, Walter M. Katz
  • Patent number: 7533359
    Abstract: An improved method, system, and computer program product is disclosed for predicting the geometric model of transistors once manufacturing and lithographic process effects are taken into consideration. This provides a much more accurate approach for modeling transistors since it is the actual expected geometric shapes that are analyzed, rather than an idealized model of the layout that does not accurately correspond to the actual manufactured IC product. The expected geometric shape includes systematic variations, which can be determined based on the layout, and the expected random variations, which can be determined based on the lithographic process.
    Type: Grant
    Filed: May 19, 2006
    Date of Patent: May 12, 2009
    Assignee: Cadence Design Systems, Inc.
    Inventors: Louis K. Scheffer, Joel R. Phillips
  • Patent number: 7533358
    Abstract: Method and system are disclosed for designing a circuit using an integrated sizing, layout, and extractor tool. In one embodiment, a method for designing a circuit including initializing a set of design points, where a design point comprises a design of the circuit that meets a set of predefined design specifications, determining sizes for the circuit using a size optimization iteration process, and pausing the sizing optimization iteration process periodically for updating parasitic information of the circuit. The method further includes selecting a subset of design points from the set of design points, generating a layout of the circuit using devices sizes obtained from the set of design points, generating an extracted netlist using the layout, wherein the extracted netlist includes parasitic information of the circuit, and simulating the circuit using the extracted netlist to verify the set of predefined design specifications are met.
    Type: Grant
    Filed: October 12, 2006
    Date of Patent: May 12, 2009
    Assignee: Cadence Design Systems, Inc.
    Inventors: Prakash Gopalakrishnan, Hongzhou Liu
  • Patent number: 7530047
    Abstract: A circuit design synthesis method is provided comprising: associating a first cell library with a first block of a circuit design; associating a second cell library with a second block of the circuit design; specifying at least one constraint upon the overall circuit design; mapping a portion of the first block to a cell in the first cell library based upon the at least one constraint in view of a step of mapping a portion of the second block to a cell in the second cell library; and mapping a portion of the second block to a cell in the second cell library based upon the at least one constraint in view of the step of mapping a portion of the first block to a cell in the first cell library.
    Type: Grant
    Filed: June 5, 2006
    Date of Patent: May 5, 2009
    Assignee: Cadence Design Systems, Inc.
    Inventors: Qi Wang, Ranganathan Sankaralingam
  • Patent number: 7530048
    Abstract: An apparatus and method for optical lithography verification includes filtering a lithography simulation of proposed sub-lightwave pattern formations during at least one design phase or manufacturing phase of an article of manufacture having sub-lightwave structures and then detecting design phase or manufacturing phase defects in response to the filtering of the lithography simulation.
    Type: Grant
    Filed: April 9, 2005
    Date of Patent: May 5, 2009
    Assignee: Cadence Design Systems, Inc.
    Inventor: Devendra Joshi
  • Patent number: 7523424
    Abstract: System and method for representing analog connectivity in a design written in a hardware description language are disclosed. The method includes detecting a circuit component that does not have explicit connection path in the design, where the circuit component includes one or more lower-level circuit instances arranged in one or more branches in a hierarchical graph. The method further includes creating one or more instances of the circuit component having at least one additional port than the circuit component, creating one or more ports in the corresponding one or more instances of the circuit component for providing at least an explicit connection path, and representing the design using at least the explicit connection path and the one or more ports of the corresponding one or more instances.
    Type: Grant
    Filed: November 30, 2005
    Date of Patent: April 21, 2009
    Assignee: Cadence Design Systems, Inc.
    Inventors: Abhijeet Kolpekwar, Scott Cranston, Peter Frey
  • Patent number: 7523370
    Abstract: During testing of an integrated circuit (IC), a channel masking capability is used for masking out unknown or unpredictable (X) values from being compressed into a signature register. The approach provides flexibility to allow for masking of unknown values, while avoiding many of the problems caused by over-masking of known values. The circuitry added to the design to allow for masking is reasonably small, and provides an effective way of masking unknown values during the testing process.
    Type: Grant
    Filed: September 15, 2004
    Date of Patent: April 21, 2009
    Assignee: Cadence Design Systems, Inc.
    Inventor: Brion Keller
  • Patent number: 7519940
    Abstract: An apparatus and method of compensating for lens imperfections in a projection lithography tool, includes extracting from a diffraction image created by the projection lithography tool a lens transmittance function, and then using the extracted lens transmittance function as a compensator in the lithography projection tool. Another preferred apparatus and method of synthesizing a photomask pattern includes obtaining a phase and an amplitude of a transmittance function of an imaging system; forming a computational model of patterning that includes the transmittance function of the imaging system; and then synthesizing a mask pattern from a given target pattern, by minimizing differences between the target pattern and another pattern that the computational model predicts the synthesized mask pattern will form on a wafer.
    Type: Grant
    Filed: August 13, 2005
    Date of Patent: April 14, 2009
    Assignee: Cadence Design Systems, Inc.
    Inventors: Hsu-Ting Huang, Abdurrahman Sezginer
  • Patent number: 7516433
    Abstract: Disclosed is an improved approach for maintaining the structures for objects in a layout. A single type of structure is maintained that can be used to store or track a polygon of any shape, as long as the shape possesses a supported number of sides. The structure is capable of supporting irregular polygons or objects having angled edges. In one approach, the structure maintains information about each polygon as if that polygon is an octagon. Therefore, any polygon having eight or less orthogonal or diagonal sides can be supported using this structure.
    Type: Grant
    Filed: August 21, 2006
    Date of Patent: April 7, 2009
    Assignee: Cadence Design Systems, Inc.
    Inventors: Steven Lee Pucci, Eric Martin Nequist
  • Publication number: 20090089722
    Abstract: Aspects for optimized mapping of source elements to destination elements as interconnect routing assignments are described. The aspects include utilizing chosen rules to establish a priority for mapping, and generating mapping assignments based on the priority. The mapping assignments are recursively refined to converge on an optimized solution.
    Type: Application
    Filed: December 9, 2008
    Publication date: April 2, 2009
    Applicant: Cadence design systems, Inc.
    Inventors: Tyler J. Lockman, Phuong Ha-Uyen Landry
  • Publication number: 20090083685
    Abstract: A method for generating timing constraint systems, where the constrained object is a digital circuit, is provided, where the constraints are generated for the use of a digital logic optimization (synthesis) tool. The synthesis tool is used to optimize the circuit, under the applied constraints, so that the circuit exhibits certain desirable timing properties, while at the same time minimizing hardware cost and various other properties. The particular class of timing constraints generated by the disclosed invention is useful when the circuit is to be retimed after optimization. Typically, the joint use of the described invention and retiming results in improvements in the overall cost/performance tradeoff curve of the design.
    Type: Application
    Filed: November 26, 2008
    Publication date: March 26, 2009
    Applicant: Cadence Design Systems, Inc.
    Inventors: Alexander GIDON, David Knapp
  • Patent number: 7506294
    Abstract: A system and method for modeling an IC (integrated circuit) employs a mesh model and a grid model for separating impedance effects between nearby and far-away pairs of mesh elements. Models for relating currents and voltages can be incrementally adapted from other designs or design elements in applications including mixed-signal, analog and RF (radio frequency) circuits.
    Type: Grant
    Filed: November 17, 2006
    Date of Patent: March 17, 2009
    Assignee: Cadence Design Systems, Inc.
    Inventors: Enis Aykut Dengi, Feng Ling, Ben Song, Warren Harris
  • Patent number: 7506300
    Abstract: A method of modifying polygons in a data set mask-less or mask based optical projection lithography includes: 1) mapping the data set to a figure-of-demerit; 2) moving individual polygon edges to decrease the figure-of-demerit; and 3) disrupting the set of polygons to enable a further decrease in the figure-of-demerit, wherein disrupting polygons includes any of the following polygon disruptions: breaking up, merging, or deleting polygons.
    Type: Grant
    Filed: August 13, 2005
    Date of Patent: March 17, 2009
    Assignee: Cadence Design Systems, Inc.
    Inventors: Abdurrahman Sezginer, Roy Prasad