Abstract: An improved method, system, computer program product, and electronic design structures which provides the flexibility to IC designers to be able to relax the design rules to increase the yield and improve the layout productivity is disclosed. In some disclosed approaches, automated interactive aids and batch tools are provided which can assist in optimizing the final layouts for yield at the initial placement and/or routing stages for optimizing yield. Provided in some disclosed approaches are automated capability to layout designers at the mos devices level to configure mos devices as per different DFY recommendations from the foundry without negative effects on the overall chip area (or cell size). The design rules may be relaxed selectively on an instance basis and wherever possible or desirable.
Type:
Grant
Filed:
July 11, 2006
Date of Patent:
March 17, 2009
Assignee:
Cadence Design Systems, Inc.
Inventors:
Rajan Arora, Umesh Sisodia, Anurag Jain
Abstract: The present invention introduces methods of creating floor plans and placements for non Manhattan integrated circuits with existing electronic design automation tools. To create a floor plan, an existing Manhattan based floor planning tool is used. The die size for the floor plan is reduced to take into account the improved wiring density of non Manhattan wiring. A non Manhattan global router is then used on the floor plan to create pin placements. The floor plan may create a floor plan having circuit modules with beveled corners to take advantage of diagonal wiring. To create a placement, an existing Manhattan based placer is first used to create an initial placement. The initial placement is then processed by a non Manhattan aware post processor. The post processor performs local optimizations on the initial placement to improve the placement for a non Manhattan routed integrated circuit.
Abstract: A system and method for isolating defects in scan chains by performing diagnostics fault simulation on chosen faults that are consistent with the nature of a scan chain defect, while keeping information about predictable failures. The effects of defects at specific locations on the scan chain are modeled by compositing the effects of a subset of the faults for each defect. Each composite, which models a specific scan chain defect, is evaluated in terms of how well it predicts the failures measured at a tester, and assigned a score based on that evaluation. The composite with the highest score identifies the modeled defect which is the closest to predicting the results measured at the tester, and therefore the location on the scan chain that has the highest probability of containing the actual defect.
Type:
Grant
Filed:
March 20, 2006
Date of Patent:
February 24, 2009
Assignee:
Cadence Design System, Inc.
Inventors:
Thomas W. Bartenstein, Joseph Swenton, David Sliwinski
Abstract: Some embodiments provide an analytical placement method that considers diagonal wiring. This method formulates an objective function that accounts for the use of diagonal wiring during routing. Some embodiments use horizontal, vertical, and ±45° diagonal lines. For such a wiring model, some embodiments use the following objective function: Function = ? n ? ? p ? ( n ) ? b i , j ? ( 1 2 ? ( ? + ( x i - x j ) 2 + ? + ( y i - y j ) 2 ) + ( 1 - 1 2 ) ? ? + ( x i - x j ) 2 + ( y i - y j ) 2 - 2 ? ( x i - x j ) 2 ? ( y i - y j ) 2 ? + ( x i - x j ) 2 ? ( y i - y j ) 2 ) In this equation, n represents a net, p(n) represents a unique pair of pins i and j of the net n, x and y represent the x-, and y-coordinates of a particular pin, and bi,j represents a weighting factor that biases the function based on the desired closeness of pins i and j.
Type:
Grant
Filed:
March 6, 2006
Date of Patent:
February 17, 2009
Assignee:
Cadence Design Systems, Inc.
Inventors:
Andrew Siegel, Steven Teig, Hussein Etawil
Abstract: Method and system for improving yield of an integrated circuit are disclosed. The method includes optimizing a design of the integrated circuit according to a set of predefined design parameters to generating design points that meet a set of predefined design specifications, analyzing the design points to form clusters comprising the design points, determining a representative design point from the clusters comprising the design points, running a statistical simulation to determine a yield of the design using the representative design point and a statistical model of manufacturing process variations, generating statistical corners in accordance with results of the statistical simulation, and optimizing the design in accordance with the statistical corners using an iterative process.
Abstract: Described is a process for performing an improved mixed frequency-time algorithm to simulate responses of a circuit that receives a periodic sample signal and at least one information signal. The process selects a set of evenly spaced distinct time points and a set of reference time points. Each of the reference points is associated with a distinct time point, and a reference time point is a signal period away from its respective distinct time point. The process finds a first set of relationships between the values at the distinct time points and the values at the reference time points. The process also finds a second set of relationships between the values at the distinct time points and the values at the reference time points. The process then combines the first and second sets of relationships to establish a system of nonlinear equations in terms of the values at the distinct time points only. By solving the system of nonlinear equations, the process finds simulated responses of the circuit in time domain.
Type:
Grant
Filed:
May 15, 2000
Date of Patent:
February 17, 2009
Assignee:
Cadence Design Systems, Inc.
Inventors:
Dan Feng, Joel R. Phillips, Kenneth Kundert
Abstract: A method and system are provided for optimizing physical implementation of an electronic circuit responsive to simulation analysis thereof. The method and system include schematically defining the electronic circuit to include a plurality of circuit elements interconnected at respective nodes by a plurality of nets, and acquiring parametric values for a plurality of predetermined operational parameters from simulated operation of the electronic circuit. The parametric values are automatically processed to generate a plurality of parametric constraints corresponding thereto for optimizing physical implementation of the electronic circuit. A circuit layout at least partially representing a physical implementation of the schematic definition is then generated. The circuit layout, which includes a plurality of devices interconnected by a plurality of tracks, is adaptively configured in accordance with the parametric constraints.
Abstract: A method and an apparatus to perform statistical static timing analysis have been disclosed. In one embodiment, the method includes performing statistical analysis on performance data of a circuit from a plurality of libraries at two or more process corners using a static timing analysis module, and estimating performance of the circuit at a predetermined confidence level based on results of the statistical analysis during an automated design flow of the circuit without using libraries at the predetermined confidence level.
Abstract: A reduced order model of a distributed time invariant system is produced by projecting system matrices onto smaller matrices, interpolating the matrices and placing into a state-space system. The system matrices are an internal representation of the distributed time invariant system which comprises a description of the system to be modeled, mainly, for example, its inputs and outputs. The method is applied to distributed systems and guarantees accuracy in complicated systems and produces well-behaved models appropriate for use in simulators and simulations.
Abstract: A logic failure diagnosis system for performing logic failure diagnosis and methods for manufacturing and using same. The logic failure diagnosis system includes a signature register system and a space compaction system and, during testing, receives data values from a predetermined number of scan chains. During each scan cycle, the signature register system combines a set of data values with a set of recirculated data values to provide a set of data signature values. The signature register system recirculates the data signature values from the preceding scan cycle to provide the recirculated data values. The space compaction system compresses the data signature values to provide a compressed scan chain signature for the scan chains. The compressed scan chain signature can be compared with a set of expected values to determine whether the scan chains include any erroneous values and, if so, to identify a source of the erroneous values.
Abstract: A method for defining and producing a power grid structure of an IC that minimizes the area of the power grid structure area and the diagonal wiring blockage caused by the power grid structure while still meeting design constraints. A power grid planner is used to determine dimensions and locations of power grid components for each IC layer using a power grid formula, an objective for the power grid formula, a set of constraints, and a set of parameters. The method also includes processes of a power grid router, power grid verifier, and global signal router that are used iteratively with processes of the power grid planner to continually refine the dimensions and locations of the power grid components until the power grid structure meets design constraints and until global signal routing is successful on each layer of the IC.
Abstract: Some embodiments of the invention provide a method of routing. The method selects a net with a set of routable elements in a multi-layer layout region. In some embodiments, the method identifies a route for the net based on different congestion goals on different layers. In other embodiments, the method identifies a route for the net based on different congestion goals between different layer pairs. In some embodiments, the method identifies a route for the net based on both the different congestion goals on different layers and between different layer pairs.
Abstract: An apparatus and method for improving image quality in a photolithographic process includes calculating a figure-of-demerit for a photolithographic mask function and then adjusting said photolithographic mask function to reduce the figure of demerit.
Abstract: A method to simulate an electronic circuit includes determining process parameters and a process variation for each process parameter, and determining a value for each of a plurality of components of the circuit as a function of the process variations.
Abstract: A method of producing multiple models of a hardware (integrated circuit) design including: translating a master model of a design of the integrated circuit to at least first and second models that are functionally equivalent to the master model and that are at different levels of abstraction from each, other and in which each of the first and second models includes integrated circuit timing information that is accurate for its level of abstraction.
Type:
Grant
Filed:
December 30, 2005
Date of Patent:
December 30, 2008
Assignee:
Cadence Design Systems, Inc.
Inventors:
Yosinori Watanabe, Luciano Lavagno, Alex Kondratyev
Abstract: Some embodiments of the invention provide a routing method. The routing method receives a set of nets to route in a region of an integrated circuit (“IC”) layout. The routing method defines routes for the nets in a manner that ensures that each segment of each route is not less than a minimum length that is required for the segment. In some embodiments, the routing method identifies a route for a net by performing one or more path search operations. Each path search operation identifies one set of path expansions that can be used to define a segment of a route for the net. A path search operation in some embodiments performs a viability check for each path expansion that it identifies, in order to ensure that any segment that might eventually result from an identified set of path expansions satisfies its minimum required length.
Abstract: Aspects for clock tree synthesis of an integrated circuit include performing top-level clock tree synthesis, and estimating one or more block-level clock tree structures of the integrated circuit. The block-level clock tree structure is estimated based on a grid-based clock tree estimation, wherein each block is subdivided into one or more grids. The aspects further include merging of the estimated block-level clock tree structures with the top-level clock tree synthesis.
Abstract: Overloaded regions in the routing space of a physical network are resolved via a routing procedure composed of a topological routing phase and a geometric routing phase. The overloads are resolved in the topological routing phase where the constraints of routing are less prohibitive. Multiple topological transformations directed toward resolving the overloads are executed in the topological routing phase prior to a geometric arrangement being realized. The topological transformations may be applied concurrently by way of a multi-threaded embodiment of the invention.
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:
Grant
Filed:
September 30, 2005
Date of Patent:
December 9, 2008
Assignee:
Cadence Design Systems, Inc.
Inventors:
Tyler J. Lockman, Phuong Ha-Uyen Landry
Abstract: Aspects for generating a current source model of a gate include extracting the current source model of the gate. The current source model of the gate is a function of time and output voltage of the gate. Further, the current source model of the gate is extracted based on data present in a timing library. The aspects further include storing the current source model of the gate. This is carried out by using the existing, specified timing library for current source models. In this manner, additional expenditure is not incurred for formulating another timing library.