Patents Assigned to Cadence Design Systems
  • Patent number: 7346872
    Abstract: A system and method for performing a timing analysis on virtual component blocks or other circuit models is provided wherein functional information obtained from the circuit's control inputs and their useful combinations is used to improve accuracy. The control inputs and data inputs for a circuit block are identified. Each functionally meaningful or useful control input combination is applied to the circuit block, and the topological delay for the data inputs are determined only along the paths that are not blocked by the control inputs. The delays along paths that are blocked are ignored. The analysis is further augmented by determining the topological delay for all paths originating at control inputs, without regard to blocking of paths, so as to reduce the chance for possible underestimation of delays from the data inputs.
    Type: Grant
    Filed: September 24, 2002
    Date of Patent: March 18, 2008
    Assignee: Cadence Design Systems, Inc.
    Inventors: Hakan Yalcin, Robert J. Palmero, Karem A. Sakallah, Mohammad S. Mortazavi, Cyrus Bamji
  • Patent number: 7340702
    Abstract: Inductive proof can be an improvement to bounded verification. Forward and backward inductive proof methods are disclosed, which can improve the process of verifying properties of circuit designs. An inductive set of one or more states includes passing a first property of a circuit design. State of the inductive set passing at least the first property of the circuit design are transitioning by at least one step in a forward direction, resulting in transitioned states. It is determined if the transitioned states of the inductive set pass at least the first property of the circuit design. At least the transitioning and the determining are repeated, until at least, the determining results in the transitioned states of the inductive set passing at least the first property of the circuit design.
    Type: Grant
    Filed: July 23, 2003
    Date of Patent: March 4, 2008
    Assignee: Cadence Design Systems, Inc.
    Inventor: Bow-Yaw Wang
  • Patent number: 7340711
    Abstract: Some embodiments of the invention provide a method for defining routes in a design layout. The method defines at least one particular wiring layer that has at least two regions with different local preferred wiring directions. The method then uses the differing local preferred wiring directions to define a detailed route on the wiring layer. In some embodiments, the method defines a first route that traverse first and second regions between two layers by using a first via that has a first pad in the second region. The method also defines a second route that traverses the second region and a third region in the two layers by using a second via that has a second pad in the second region, where the first and second pads have different shapes.
    Type: Grant
    Filed: December 6, 2004
    Date of Patent: March 4, 2008
    Assignee: Cadence Design Systems, Inc.
    Inventors: Asmus Hetzel, Etienne Jacques, Deepak Cherukuri
  • Patent number: 7337421
    Abstract: A method for modifying instances of a repeating pattern in an integrated circuit design to correct for perturbations during rendering is described. In the typical embodiment, these corrections are optical proximity corrections that correct for optical effects during the projection of the mask pattern onto the wafer and/or processing effects for example photoresist response and etching effects. The method comprises determining a correction for the repeating pattern based on a first set of tolerances for features of the repeating pattern. Then, the suitability of the corrections is evaluated for instances of the repeating pattern in the integrated circuit design based on a second set of tolerances, which is different from the first set of tolerances. This can be used to preserve much of the hierarchy of the layout data in the corrected, or lithography, data. This can be achieved during the OPC process, thus avoiding the post OPC compaction.
    Type: Grant
    Filed: September 30, 2004
    Date of Patent: February 26, 2008
    Assignee: Cadence Design Systems, Inc.
    Inventor: Vishnu Govind Kamat
  • Patent number: 7331026
    Abstract: A system for generating a layout of an integrated circuit is disclosed. The system includes at least one processing unit for executing computer programs, a graphical-user-interface for viewing representations of the integrated circuit on a display and observing the layout of the integrated circuit, and a memory for storing databases of the integrated circuit. The system further includes means for retrieving locations of a plurality of devices from a schematic of the integrated circuit, means for retrieving user-specified placement constraints, and means for placing the devices in accordance with the locations and the user-specified placement constraints.
    Type: Grant
    Filed: October 12, 2004
    Date of Patent: February 12, 2008
    Assignee: Cadence Design Systems, Inc.
    Inventor: Hemanth Sampath
  • Patent number: 7328419
    Abstract: Disclosed is a method, system, and article of manufacture for a one-pass approach for implementing metal-fill for an integrated circuit. Also disclosed is a method, system, and article of manufacture for implementing metal-fill that is coupled to a tie-off connection. An approach that is disclosed comprises a method, system, and article of manufacture for implementing metal-fill having an elongated shape that corresponds to the length of whitespace. Also disclosed is the aspect of implementing metal-fill that matches the routing direction. Yet another disclosure is an implementation of a place & route tool incorporating an integrated metal-fill mechanism.
    Type: Grant
    Filed: November 19, 2002
    Date of Patent: February 5, 2008
    Assignee: Cadence Design Systems, Inc.
    Inventors: Thanh Vuong, William H. Kao, David C. Noice
  • Patent number: 7328143
    Abstract: A method for building a hierarchical representation of a circuit for simulation includes 1) receiving a source file containing SPICE-like netlist descriptions of the circuit in a flattened representation; 2) generating a primitive database using the source file, where the primitive database includes a geometries-describing section for storing a plurality of primitive subcircuit blocks; 3) generating an instance database using the geometries-describing section, where the instances database includes instance subcircuit blocks corresponding to explicitly-expressed primitive subcircuit blocks with predefined geometric values; 4) generating a simulation database using the instance database, where the simulation database includes simulation subcircuit blocks corresponding to fully-flattened instance subcircuit blocks; and 5) simulating the circuit using the simulation database, the instance database, and the primitive database.
    Type: Grant
    Filed: February 15, 2005
    Date of Patent: February 5, 2008
    Assignee: Cadence Design Systems, Inc.
    Inventor: Bruce W. McGaughy
  • Patent number: 7325206
    Abstract: An electronic design is generated for an integrated circuit that is to be fabricated in accordance with the electronic design by a process that will impart topographically induced feature dimension variations to the integrated circuit. The generating includes adjusting the electronic design based on predictions of topographical and topographical-related feature dimension variations by a pattern-dependent model. An RC extraction tool is used in conjunction with the generating and adjusting of the electronic design. The process includes a fabrication process that will impart topographical variation to the integrated circuit and a lithography or etch process. Placement attributes for elements of the integrated circuit are determined.
    Type: Grant
    Filed: December 17, 2002
    Date of Patent: January 29, 2008
    Assignee: Cadence Design Systems, Inc.
    Inventors: David White, Taber H. Smith
  • Patent number: 7313770
    Abstract: The present invention presents methods for modeling the high frequency and noise characterization of MOSFETs. The models may be readily implemented as part of a SPICE or other simulation in a design flow. In particular, this invention is capable of providing a sub-circuit representation of a MOSFET that can accurately predicate a MOSFET's low frequency, high frequency, and noise characterizations. An interface is described through which a user may simultaneously optimize all of these characterizations. Further, methods are presented for building models that can predicate the variations in MOSFETs due to manufacturing processes and generate a corresponding corner model.
    Type: Grant
    Filed: December 17, 2004
    Date of Patent: December 25, 2007
    Assignee: Cadence Design Systems, Inc.
    Inventors: Xisheng Zhang, Hancheng Liang, Zhihong Liu, Jianhe Guo
  • Patent number: 7310792
    Abstract: A system, method, and computer program accurately models circuit parameter variation for delay calculation. For any given circuit parameter value, a cell is characterized at just three values in the circuit parameter range. An interpolation process generates an equation to calculate delay using the characterization data from the three circuit parameter values. This delay equation calculates the delay for any value in the circuit parameter range. Similar methodology is used to model simultaneous variation of two circuit parameters. The cell is characterized at just six circuit parameter pairs to interpolate the delay equation for any circuit parameter pair in the characterized ranges. This methodology can be extended to accommodate variation of multiple circuit parameters using similar interpolation techniques.
    Type: Grant
    Filed: December 15, 2004
    Date of Patent: December 18, 2007
    Assignee: Cadence Design Systems, Inc.
    Inventors: Nishath K. Verghese, Hong Zhao
  • Patent number: 7310797
    Abstract: System and method is disclosed for breaking an integrated circuit design to be printed into two or more exposures by lithographic equipment, each of the two or more exposures has at least the minimum pitch. Together, these multiple exposures print an integrated circuit design that could not be printed in one exposure alone.
    Type: Grant
    Filed: April 14, 2006
    Date of Patent: December 18, 2007
    Assignee: Cadence Design Systems, Inc.
    Inventor: Judy Huckabay
  • Patent number: 7310793
    Abstract: Some embodiments of the invention provide vias that are not in shape of quadrilaterals. In some embodiments, some or all vias are in shape of non-quadrilateral polygons, such as octagons and hexagons. In some embodiments, some or all vias have a circular shape. Some embodiments provide a first set of vias that have a diamond shape and a second set of vias that have a rectangular shape. In some embodiments, a via can also be formed by a diamond contact and a rectangular contact. The diamond contact has four sides. In the embodiments described below, all four sides of a diamond via contact have equal sides. However, in other embodiments, a via contact can be in shape of a diamond with a pair of sides that are longer than the other pair of sides. Similarly, in the embodiments described below, the rectangular via contacts are squares with four equal sides. However, in other embodiments, the length and width of a rectangular via contact can differ.
    Type: Grant
    Filed: January 31, 2002
    Date of Patent: December 18, 2007
    Assignee: Cadence Design Systems, Inc.
    Inventors: Steven Teig, Andrew Caldwell
  • Publication number: 20070288876
    Abstract: Disclosed is an improved approach for organizing, analyzing, and operating upon polygon data which significantly reduces the amount of data required for processing while keeping elements non-interfacing with each other. According to one approach, clusters of elements are extracted which are then handled separately. In some approaches, a set of polygons forms a cluster if for any two polygons from the set of polygons there exists a sequence of polygons from the set such that the distance between any sequential polygons are less than or equal to a given threshold number. Rather than analyzing each and every polygon in the design, repetitive unique patterns are analyzed once, which are then replicated for all clusters which have the same repetitive pattern.
    Type: Application
    Filed: January 17, 2007
    Publication date: December 13, 2007
    Applicant: Cadence Design System, Inc.
    Inventors: Anwar Irmatov, Alexander Belousov, Eitan Cadouri, Andrei Gratchev, Alexander Ryjov, Laurent Thenie
  • Patent number: 7308666
    Abstract: A method and an apparatus to improve hierarchical design implementation have been disclosed. In one embodiment, the method includes deriving boundary logic of at least one of a plurality of partitions in an integrated circuit (IC) design, marking the boundary logic of the at least one of the plurality of partitions based on at least one predetermined criterion, and performing implementation of the IC design using the marked boundary logic.
    Type: Grant
    Filed: December 16, 2004
    Date of Patent: December 11, 2007
    Assignee: Cadence Design Systems, Inc.
    Inventor: Hung-Chun Li
  • Publication number: 20070282589
    Abstract: A method, apparatus and method for compiling a hardware design for performing hardware emulation using synchronized processors is described. The apparatus comprises a plurality of processors defining a processor group for evaluating data regarding a hardware design and a synchronizer for synchronizing the operation of the processor group while emulating at least a portion of the hardware design. The method comprises providing a synchronization signal to a plurality of processors defining a processor group for evaluating data regarding a hardware design, receiving a ready signal from the processor group, and providing an execution signal to the processor group, where the execution signal causes the processor group to evaluate a submodel. The method for compiling the hardware design comprises converting at least one high-level construct into a sequence of operations and identifying a sequence of operations that comprise at least one conditional submodel.
    Type: Application
    Filed: May 31, 2006
    Publication date: December 6, 2007
    Applicant: Cadence Design Systems, Inc.
    Inventors: Mikhail Bershteyn, Charles Berghorn, Mitchell G. Poplack
  • Patent number: 7302672
    Abstract: A method for generating lithography masks includes generating integrated circuit design data and using context information from the integrated circuit design data to write a mask.
    Type: Grant
    Filed: June 1, 2005
    Date of Patent: November 27, 2007
    Assignee: Cadence Design Systems, Inc.
    Inventors: Robert C. Pack, Louis Scheffer
  • Patent number: 7299429
    Abstract: A system and method which allows for burst licensing, particularly for use in a circuit design and analysis system in which designers use tools to assist in characterizing and verifying the circuit. Burst licensing is used to provide licenses on an ‘as and when required’ basis to allow system users or customers to carry out massive parallelism of the simulation tasks when run from selected tools. When the system receives a request to start a task, the system checks-out a burst license for use in processing the task, and assigns the license to a particular CPU. The task is then performed at that CPU, and once completed the burst license is returned to the license pool.
    Type: Grant
    Filed: December 2, 2004
    Date of Patent: November 20, 2007
    Assignee: Cadence Design Systems, Inc.
    Inventors: Paul C. Foster, James Britton, Alan Mayes, Richard E. Seiter
  • Patent number: 7299428
    Abstract: The present invention includes a method for detecting model stamping errors during circuit simulation without the need for golden data. The method checks for model stamping errors by determining whether entries in model stamping matrices interrelate according to a plurality of preset rules before circuit equations are solved.
    Type: Grant
    Filed: February 6, 2004
    Date of Patent: November 20, 2007
    Assignee: Cadence Design Systems, Inc
    Inventors: Yutao Ma, Bruce McGaughy, Zhihong Liu
  • Patent number: 7299466
    Abstract: Workspace definitions, which define an execution environment, can be associated with jobs. A work request is processed to automatically determine that tasks that are progeny of a given job inherit the association with the workspace definition, and therefore, that the tasks should be executed using the execution environment defined in the workspace definition. However, different execution environments can be defined for progeny of a given parent job, essentially overriding the inheritance from the parent job. According to an embodiment, a set of resources associated with an execution environment is configured such that the resources are accessible by two or more computers of a group of networked computers, such as a server farm, without requiring configuring duplicate sets of the resources. Furthermore, in a server farm computing environment, an execution environment associated with one or more jobs is not reliant on being created on any given computer of the server farm.
    Type: Grant
    Filed: September 19, 2002
    Date of Patent: November 20, 2007
    Assignee: Cadence Design Systems, Inc.
    Inventors: Darren Pulsipher, Nancy Hannaford
  • Patent number: 7296246
    Abstract: The present invention provides a process for constrained clock skew scheduling which computes for a given number of clocking domains the optimal phase shifts for the domains and the assignment of the individual registers to the domains. For the within domain latency values, the algorithm can assume a zero-skew clock delivery or apply a user-provided upper bound. Experiments have demonstrated that a constrained clock skew schedule using a few clocking domains combined with small within-domain latency can reliably implement the full sequential optimization potential to date only possible with an unconstrained clock schedule.
    Type: Grant
    Filed: November 5, 2003
    Date of Patent: November 13, 2007
    Assignee: Cadence Design Systems, Inc.
    Inventors: Andreas Kuehlmann, Kaushik Ravindran, Ellen Sentovich