A method using a generate-and-verify computer program product to generate by repetitive passes a design rules checking computer program, wherein the design rules are described in a file called a runset. The design rules checking program is used for exhaustive testing of VLSI chips for compliance to the design rules of a given VLSI fabrication process. The runset is repeatedly iterated in loop fashion with respect to a testcase file containing groups of layout structures or shapes used for verifying the correctness of the runset. A general purpose shapes processing program creates an error shapes file for storing geometrical errors found in each said layout structure. Two additional shapes are used in the verification process: user boundary shapes for defining areas in which errors are not to be detected for a given design rule, and automated boundary shapes created to surround each said layout structure with a boundary that defines regions where error shapes can occur. An association table is created which is a compilation of the error shapes, user boundary shapes, and automated boundary shapes associated with each layout structure. The association table is processed to determine the correctness of the runset. The runset is modified to correct each valid error. The repetitive passes continue until a final runset is generated. This final runset becomes the input to design rules checking computer program product and customizes the program for a given VLSI fabrication process.

Method for verifying design rule checking software

A portable, personal storage and carrying case for an e-liquid e-cigarette PV in which the case includes: (a) a power source for re-charging a rechargeable battery in the PV; (b) a reservoir for holding e-liquid; and (c) a fluid transfer system adapted to transfer e-liquid from the reservoir to a chamber in the PV.

E-cigarette personal vaporizer

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.

Systems, methods, and apparatus to perform statistical static timing analysis

The present invention comprises a method of optimizing a circuit design having a plurality of library cells. In one embodiment, the method includes the steps of providing a plurality of logically equivalent cells that vary in at least one design parameter, the plurality of logically equivalent cells having a relatively continuous spectrum of values of one of the design parameters, evaluating a selected characteristic of the circuit design; and replacing a cell in the circuit design with a cell an equivalent cell.

Optimization of circuit designs using a continuous spectrum of library cells

A method for modeling integrated circuit designs in a hierarchical design automation system which utilizes a block abstraction including therein set of all database objects (cells, nets, wires, vias, and blockages) that are necessary to achieve accurate placement, routing, extraction, simulation, and verification of the block's ancestors in the hierarchy.

Representing the design of a sub-module in a hierarchical integrated circuit design and analysis system

With each semiconductor process node, the impacts on performance of environmental and semiconductor process variations become a larger portion of the cycle time of the product. Simple guard-banding for these effects leads to increased product development times and uncompetitive products. In addition, traditional static timing methodologies are unable to cope with the large number of permutations of process, voltage, and temperature corners created by these independent sources of variation. In this paper we will discuss the sources of variation; by introducing the concepts of systematic inter-die variation, systematic intra-die variation and intra-die random variation. We will show that by treating these forms of variations differently, we can achieve design closure with less guard-banding than traditional methods.

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Process and environmental variation impacts on ASIC timing

A computerized tool or method that calculates the capacitance and resistance of each global wire on the chip, one wire at a time. The invention steps along a track containing a wire segment, grid point by grid point, calculating the resistance and capacitance at that point. At each grid point it searches the neighboring tracks within the surrounding cube for adjacent elements that could cause capacitive effects or affect the resistance of the wire. The method delivers capacitance and resistance values for each process condition for a grid unit length of wire, given the wire type and 3 dimensional environment of the wire segment. The capacitance and resistance at a grid point along the wire are generally determined by one table lookup for wire types based on the surrounding environment. These values are added along wire segments to deliver accurate 3 dimensional capacitances and resistances. The invention can also provide for wires and spaces of various types and widths not provided for in the tables and for calculation of net to net coupling capacitances.

Three dimensional track-based parasitic extraction

Meeting the tight performance specifications mandated by the customer is critical for contract manufactured ASICs. To address this, at speed test has been employed to detect subtle delay failures in manufacturing. However, the increasing process spread in advanced nanometer ASICs poses considerable challenges to predicting hardware performance from timing models. Performance verification in the presence of process variation is difficult because the critical path is no longer unique. Different paths become frequency limiting in different process corners. In this paper, we present a novel variation-aware method based on statistical timing to select critical paths for structural test. Node criticalities are computed to determine the probabilities of different circuit nodes being on the critical path across process variation. Moreover, path delays are projected into different process corners using their linear delay function forms. Experimental results for three multimillion gate ASICs demonstrate the effectiveness of our methods.

Variation-aware performance verification using at-speed structural test and statistical timing

According to the present embodiment, a method for calculating the parasitic capacitance in a semiconductor device is disclosed. According to the preferred method, a layout file containing the shapes of a semiconductor device is provided. The dimensions of the layout file are then adjusted to wafer dimensions so as reflect actual production devices. The shapes of the layout file are then partitioned into simpler shapes, typically abutted rectangles, called tiles. Each tile is then decomposed into overlap and fringe capacitance components, each component having a uniform capacitance environment with respect to its capacitance elements. The parasitic capacitance of the semiconductor device can thus be accurately computed, with an efficient use of resources. Additionally the preferred embodiment is easily adaptable to a wide range of technology types.

Method and apparatus for modeling capacitance in an integrated circuit

Methods for analyzing the timing in integrated circuits and for reducing the pessimism in timing slack calculations in static timing analysis (STA). The methods involve grouping and canceling the delay contributions of elements having similar delays in early and late circuit paths. An adjusted timing slack is calculated using the delay contributions of elements having dissimilar delays. In some embodiments, the delay contributions of elements having dissimilar delays are root sum squared. Embodiments of the invention provide methods for reducing the pessimism due to both cell-based and wire-dependent delays. The delays considered in embodiments of the invention may include delays due to the location of elements in a path.

Peter A. Habitz

Papers

Process and environmental variation impacts on ASIC timing

Three dimensional track-based parasitic extraction

Variation-aware performance verification using at-speed structural test and statistical timing

Method and apparatus for modeling capacitance in an integrated circuit

Method and system for evaluating timing in an integrated circuit