Abstract: A method for performing leakage analysis includes receiving information specifying an integrated circuit. A neighborhood of shapes associated with the integrated circuit is then determined. Leakage information associated with the integrated circuit is generated based on the neighborhood of shapes. The neighborhood of shapes may be determined by determining a first set of spacings to a boundary of a first cell from an internal shape. A second set of spacings may be determined from the boundary of the first cell to a shape of a second cell. A lithography process may be characterized using the first and second set of spacings.

Abstract: A method for performing leakage analysis includes receiving information specifying an integrated circuit. A neighborhood of shapes associated with the integrated circuit is then determined Leakage information associated with the integrated circuit is generated based on the neighborhood of shapes. The neighborhood of shapes may be determined by determining a first set of spacings to a boundary of a first cell from an internal shape. A second set of spacings may be determined from the boundary of the first cell to a shape of a second cell. A lithography process may be characterized using the first and second set of spacings.

Abstract: A method for performing leakage analysis includes receiving information specifying an integrated circuit. A neighborhood of shapes associated with the integrated circuit is then determined. Leakage information associated with the integrated circuit is generated based on the neighborhood of shapes. The neighborhood of shapes may be determined by determining a first set of spacings to a boundary of a first cell from an internal shape. A second set of spacings may be determined from the boundary of the first cell to a shape of a second cell. A lithography process may be characterized using the first and second set of spacings.

Abstract: A method for performing timing analysis includes receiving information specifying an integrated circuit. A neighborhood of shapes associated with the integrated circuit is then determined. Delay information associated with the integrated circuit is generated based on the neighborhood of shapes. The neighborhood of shapes may be determined by determining a first set of spacings to a boundary of a first cell from an internal shape. A second set of spacings may be determined from the boundary of the first cell to a shape of a second cell. A lithography process may be characterized using the first and second set of spacings.

Abstract: An efficient method and computer program for modeling and improving stating memory performance across process variations and environmental conditions provides a mechanism for raising the performance of memory arrays beyond present levels/yields. Statistical (Monte-Carlo) analyses of subsets of circuit parameters are performed for each of several memory performance variables and then sensitivities of each performance variable to each of the circuit parameters are determined. The memory cell design parameters and/or operating conditions of the memory cells are then adjusted in conformity with the sensitivities, resulting in improved memory yield and/or performance. Once a performance level is attained, the sensitivities can then be used to alter the probability distributions of the performance variables to achieve a higher yield.

Abstract: A method of modeling electromagnetism in an irregular conductive plane, by dividing the surface into a grid of unequal and unaligned rectangles, assigning a circuit node location to a center of each rectangle, and calculating capacitive and inductive parameters based on the center circuit node locations. Rectangulation is accomplished using automated, recursive bisection. Capacitive segments are assigned to each circuit node and coincide with the corresponding rectangles. Inductive segments are assigned between adjacent rectangle pairs, with a width of an inductive segment defined as the common boundary of the corresponding pair of rectangles and the length of the inductive segment defined as the normal distance between circuit nodes of the two rectangles. Placement of the circuit nodes at the centers of the rectangles significantly reduces the number of nodes and segments, and provides a faster yet comprehensive analysis framework.

Abstract: An internally asymmetric method for evaluating static memory cell dynamic stability provide a mechanism for raising the performance of memory arrays beyond present levels/yields. By altering the internal symmetry of a static random access memory (SRAM) memory cell, operating the cell and observing changes in performance caused by the asymmetric operation, the dynamic stability of the SRAM cell can be studied over designs and operating environments. The asymmetry can be introduced by splitting one or both power supply rail inputs to the cell and providing differing power supply voltages or currents to each cross-coupled stage. Alternatively or in combination, the loading at the outputs of the cell can altered in order to affect the performance of the cell. A memory array with at least one test cell can be fabricated in a production or test wafer and internal nodes of the memory cell can be probed to provide further information.

Abstract: A memory cell having an asymmetric connection for evaluating dynamic stability provides a mechanism for raising the performance of memory arrays beyond present levels/yields. By operating the cell and observing changes in performance caused by the asymmetry, the dynamic stability of the SRAM cell can be studied over designs and operating environments. The asymmetry can be introduced by splitting one or both power supply rail inputs to the cell and providing differing power supply voltages or currents to each crosscoupled stage. Alternatively or in combination, the loading at the outputs of the cell can altered in order to affect the performance of the cell. A memory array with at least one test cell can be fabricated in a production or test wafer and internal nodes of the memory cell can be probed to provide further information.

Abstract: A method for evaluating leakage effects on static memory cell access time provides a mechanism for raising the performance of memory arrays beyond present levels/yields. By altering the states of other static memory cells connected to the same bitline as a static memory cell under test, the effect of leakage on the access time of the cell can be observed. The leakage effects can further be observed while varying the internal symmetry of the memory cell, operating the cell and observing changes in performance caused by the asymmetric operation. The asymmetry can be introduced by splitting one or both power supply rail inputs to the cell and providing differing power supply voltages or currents to each cross-coupled stage.

Abstract: A ring oscillator row circuit for evaluating memory cell performance provides for circuit delay and performance measurements in an actual memory circuit environment. A ring oscillator is implemented with a row of memory cells and has outputs connected to one or more bitlines along with other memory cells that are substantially identical to the ring oscillator cells. Logic may be included for providing a fully functional memory array, so that the cells other than the ring oscillator cells can be used for storage when the ring oscillator row wordlines are disabled. One or both power supply rails of individual cross-coupled inverter stages forming static memory cells used in the ring oscillator circuit may be isolated from each other in order to introduce a voltage asymmetry so that circuit asymmetry effects on delay can be evaluated.

Abstract: An efficient method and computer program for modeling and improving stating memory performance across process variations and environmental conditions provides a mechanism for raising the performance of memory arrays beyond present levels/yields. Statistical (Monte-Carlo) analyses of subsets of circuit parameters are performed for each of several memory performance variables and then sensitivities of each performance variable to each of the circuit parameters are determined. The memory cell design parameters and/or operating conditions of the memory cells are then adjusted in conformity with the sensitivities, resulting in improved memory yield and/or performance. Once a performance level is attained, the sensitivities can then be used to alter the probability distributions of the performance variables to achieve a higher yield.

Abstract: A system and a method are disclosed for integrating the results of lithographic simulation into the physical synthesis process. The effects of lithographic variation are considered when selecting a cell from among a group of cells having equivalent function. Circuit design elements are placed and routed with consideration of the effects of lithographic variation on robustness, timing performance, and leakage current. Cells may be simulated under a variety of conditions and environments and the simulation results stored in a library for efficient lithographically optimized placements.

Abstract: A method for evaluating memory cell performance provides for circuit delay and performance measurements in an actual memory circuit environment. A ring oscillator implemented in a row of memory cells and having outputs connected to one or more bitlines along with other memory cells that are substantially identical to the ring oscillator cells is operated by the method. Logic may be included for providing a fully functional memory array, so that the cells other than the ring oscillator cells can be used for storage when the ring oscillator row wordlines are disabled. One or both power supply rails of individual cross-coupled inverter stages forming static memory cells used in the ring oscillator circuit may be isolated from each other in order to introduce a voltage asymmetry so that circuit asymmetry effects on delay can be evaluated.

Abstract: A ring oscillator row circuit for evaluating memory cell performance provides for circuit delay and performance measurements in an actual memory circuit environment. A ring oscillator is implemented with a row of memory cells and has outputs connected to one or more bitlines along with other memory cells that are substantially identical to the ring oscillator cells. Logic may be included for providing a fully functional memory array, so that the cells other than the ring oscillator cells can be used for storage when the ring oscillator row wordlines are disabled. One or both power supply rails of individual cross-coupled inverter stages forming static memory cells used in the ring oscillator circuit may be isolated from each other in order to introduce a voltage asymmetry so that circuit asymmetry effects on delay can be evaluated.

Abstract: A method for performing leakage analysis includes receiving information specifying an integrated circuit. A neighborhood of shapes associated with the integrated circuit is then determined. Leakage information associated with the integrated circuit is generated based on the neighborhood of shapes. The neighborhood of shapes may be determined by determining a first set of spacings to a boundary of a first cell from an internal shape. A second set of spacings may be determined from the boundary of the first cell to a shape of a second cell. A lithography process may be characterized using the first and second set of spacings.

Abstract: A method for performing timing analysis includes receiving information specifying an integrated circuit. A neighborhood of shapes associated with the integrated circuit is then determined. Delay information associated with the integrated circuit is generated based on the neighborhood of shapes. The neighborhood of shapes may be determined by determining a first set of spacings to a boundary of a first cell from an internal shape. A second set of spacings may be determined from the boundary of the first cell to a shape of a second cell. A lithography process may be characterized using the first and second set of spacings.

Abstract: A method of modeling electromagnetism in an irregular conductive plane, by dividing the surface into a grid of unequal and unaligned rectangles, assigning a circuit node location to a center of each rectangle, and calculating capacitive and inductive parameters based on the center circuit node locations. Rectangulation is accomplished using automated, recursive bisection. Capacitive segments are assigned to each circuit node and coincide with the corresponding rectangles. Inductive segments are assigned between adjacent rectangle pairs, with a width of an inductive segment defined as the common boundary of the corresponding pair of rectangles and the length of the inductive segment defined as the normal distance between circuit nodes of the two rectangles. Placement of the circuit nodes at the centers of the rectangles significantly reduces the number of nodes and segments, and provides a faster yet comprehensive analysis framework.

Abstract: Internally asymmetric methods and circuits for evaluating static memory cell dynamic stability provide a mechanism for raising the performance of memory arrays beyond present levels/yields. By altering the internal symmetry of a static random access memory (SRAM) memory cell, operating the cell and observing changes in performance caused by the asymmetric operation, the dynamic stability of the SRAM cell can be studied over designs and operating environments. The asymmetry can be introduced by splitting one or both power supply rail inputs to the cell and providing differing power supply voltages or currents to each cross-coupled stage. Alternatively or in combination, the loading at the outputs of the cell can altered in order to affect the performance of the cell. A memory array with at least one test cell can be fabricated in a production or test wafer and internal nodes of the memory cell can be probed to provide further information.

Abstract: Bitline variable methods and circuits for evaluating static memory cell dynamic stability provide a mechanism for raising the performance of memory arrays beyond present levels/yields. By altering the bitline pre-charge voltage of a static random access memory (SRAM) memory cell, operating the cell and observing changes in performance caused by the changes in the bitline voltage, the dynamic stability of the SRAM cell can be studied over designs and operating environments. Alternatively or in combination, the loading at the outputs of the cell can altered in order to affect the performance of the cell. In addition, cell power supply voltages can be split and set to different levels in order to study the effect of cell asymmetry in combination with bitline pre-charge voltage differences.

Abstract: A method of modeling electromagnetism in an irregular conductive plane, by dividing the surface into a grid of unequal and unaligned rectangles, assigning a circuit node location to a center of each rectangle, and calculating capacitive and inductive parameters based on the center circuit node locations. Rectangulation is accomplished using automated, recursive bisection. Capacitive segments are assigned to each circuit node and coincide with the corresponding rectangles. Inductive segments are assigned between adjacent rectangle pairs, with a width of an inductive segment defined as the common boundary of the corresponding pair of rectangles and the length of the inductive segment defined as the normal distance between circuit nodes of the two rectangles. Placement of the circuit nodes at the centers of the rectangles significantly reduces the number of nodes and segments, and provides a faster yet comprehensive analysis framework.