International Business Machines Corporation

Jin-Fuw Lee

Fook-Luen Heng

Mark Alan Lavin

Daniel Lawrence Ostapko

Rama Nand Singh

Jawahar P Nayak

Chieh-Yu Lin

Dureseti Chidambarrao

Alan Edward Rosenbluth

Thomas Ludwig

Jeffrey Paul Soreff

Nakgeuon Seong

Roger Y Tsai

Fanchieh Yee

Chak-Kuen Wong

Rama Nand Sing

A method for layout design includes steps or acts of: receiving a layout for design of an integrated circuit chip; designing mask shapes for the layout; transmitting the mask shapes to a litho simulator for generating wafer shapes; receiving the wafer shapes; calculating electrically equivalent gate lengths for the wafer shapes; analyzing the gate lengths to check for conformity against a threshold value, wherein the threshold value represents a desired value of electrically equivalent gate lengths; placing markers on the layout at those locations where the gate length violates the threshold value; and generating a histogram of gate lengths for comparing layouts for electrically equivalent gate lengths for layout quality.

Layout quality gauge for integrated circuit design

A system and method of employing patterning process statistics to evaluate layouts for intersect area analysis includes applying Optical Proximity Correction (OPC) to the layout, simulating images formed by the mask and applying patterning process variation distributions to influence and determine corrective actions taken to improve and optimize the rules for compliance by the layout. The process variation distributions are mapped to an intersect area distribution by creating a histogram based upon a plurality of processes for an intersect area. The intersect area is analyzed using the histogram to provide ground rule waivers and optimization.

System and method for employing patterning process statistics for ground rules waivers and optimization

A methodology for obtaining improved prediction of CA resistance in electronic circuits and, particularly, an improved CA resistance model adapted to capture larger than anticipated 'out of spec' regime. In one embodiment, a novel bucketization scheme is implemented that is codified to provide a circuit designer with considerably better design options for handling large CA variability as seen through the design manual. The tools developed for modeling the impact of CA variable resistance phenomena provide developers with a resistance model, such as conventionally known, modified with a new CA model Basis including a novel CA intrinsic resistance model, and, a novel CA layout bucketization model.

CA resistance variability prediction methodology

An integrated circuit (IC) including at least one combinational logic path. The features in the combinational logic path are self compensating for out-of-focus effects. In particular, field effect transistor (FET) gates may be iso-focally spaced such that the gate (critical dimension) may move with changing focus, but the gate length remains the same. Alternately, logic circuits in a path may self-compensate for focus effects on individual circuits.

Integrated circuit logic with self compensating shapes

A method and system for layout optimization relative to lithographic process windows which facilitates lithographic constraints to be non-localized in order to impart a capability of printing a given circuit with a process window beyond the process windows which are attainable with conventional simplified design rules. Pursuant to the method and system, lithographic capability and process windows are maximized to satisfy local circuit requirements and in order to achieve a maximally efficient layout. In this connection, there is employed a method utilizing a generalized lithographic process window as a measure when layout optimization is extended to a degree beyond that achieved by the simple fixed design rules which are applied to the design rules obtained is the advantage that a lithographic process window is determined purely through the calculation of image intensities and slopes, and as a result, the method can be quite rapid in application because it is possible to take advantage of known methods for rapid calculation of image intensity, and because there is obviated the need for geometrical shape processing during optimization.

Lithographic process window optimization under complex constraints on edge placement

Methods and apparatus for use in signal timing analysis with respect to a circuit having at least one gate are provided. In one aspect, the invention includes the step of determining a first constraint slew sensitivity value and a second constraint slew sensitivity value for the at least one gate according to a specified bounding technique. Then, a representative signal for the gate is computed in accordance with the first and second values including an arrival time and slew rate, wherein the representative signal bounds signal paths by bounding a maximum slew sensitivity path and a minimum slew sensitivity path. Such a representative signal may be computed for a worst case late-mode analysis and/or a best case early-mode analysis. The bounding technique may be selected by a user at the time the user inputs the schematic of the circuit on which timing analysis is to be performed. The invention provides for the use of bounding techniques such as, for example, maximum slew, minimum slew, half envelope, full envelope, modified half envelope, modified max slew, modified min slew, least upper bound, and greatest lower bound. The invention may preferably be employed in accordance with static timing analysis associated with VLSI circuit design.

Methods and apparatus for performing slew dependent signal bounding for signal timing analysis

A new clock distribution network design for VLSI circuits which effectively reduces skew without the area and power penalty associated with prior clock designs. Two wires emanating from the clock in opposite directions or, alternatively, two wires connected in series and running parallel, are used to route clock signals from the clock source to the next routing segment. The next routing segment routes clock signals to the tapping point near the circuit component by two emanated wires from the previous routing segment. Clock signals from the routing segments are fed through two-input NOR gates (alternatively, two-input NAND gates) to the clock pins. The clock signal arrival time is roughly equal to the simultaneous switching gate delay plus the average arrival times from the two paths, which turns out approximately the same across different tapping points, thus minimizing clock skews. Narrow wires may be used for routing, resulting in moderate power consumption.

Clock distribution network with dual wire routing

A new clock distribution network design for VLSI circuits which effectively reduces skew without the area and power penalty associated with prior clock designs. Two wires emanating from the clock in opposite directions or, alternatively, two wires connected in series and running parallel, are used to route clock signals from the clock source to the tapping point near the circuit component. Clock signals from the two wires are fed through two-input NOR gates (alternatively, two-input NAND gates) to the clock pins. The clock signal arrival time is roughly equal to the simultaneous switching gate delay plus the average arrival times from the two paths, which turns out approximately the same across different tapping points, thus minimizing clock skews. Narrow wires may be used for routing, resulting in moderate power consumption.

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Yorktown Heights, NY, United States of America

Jin-Fuw Lee