Lsi Corporation

Lsi Logic Corporation

Qian Cui

Sandeep Bhutani

Payman Zarkesh-Ha

Weiqing Guo

Chun Chan

John D Corbeil, Jr

Robert W Davis

Prabhakaran Krishnamurthy

Jason R Potnick

An apparatus and method to characterize a new process using an improved delay calculation. Multiple derating factors are used for different STA sign off corners that have a base corner with two pairs of off-corners. The approach of the present invention does not add any extra work in cell library characterization, while in the mean it increases the accuracy of the delay calculation and the library generation at corners other than standard corners.

Multiple derating factor sets for delay calculation and library generation in multi-corner STA sign-off flow

A method for determining a timing margin to be applied in an integrated circuit timing design. Circuit simulator path delays and static timing analysis tool path delays are determined for the integrated circuit timing design. The circuit simulator path delays are plotted in a first plot versus a percentage difference between the circuit simulator path delays and the static timing analysis tool path delays, and in a second plot are plotted versus a numerical difference between the circuit simulator path delays and the static timing analysis tool path delays. A first point is identified on the second plot having a largest numerical difference, and the circuit simulator path delay for the first point is identified. A corresponding point on the first plot having the circuit simulator path delay is found, and the percentage difference for the corresponding point is identified. A combination of both the circuit simulator path delay and the percentage difference is used as the timing margin.

Frequency dependent timing margin

A method of computing output delay in a mathematical model of an integrated circuit by sorting cells of original design of an the integrated circuit in a topological order. The original output delays for the sorted cells in the original design are computed in the topological order, to produce original output ramp times. The original output ramp times are propagated and original output delays are computed, and the original output ramp time and original output load for each cell is stored. The cells of the original design are modified to produce a modified design. For each modified cell in the topological order, a new output delay and a new output ramp time are computed and compared to the original output ramp time on the modified cell. When the new output ramp time substantially equals the original output ramp time for a modified cell, the calculations of the modified output ramp time for cells that are further down in the topological order are stopped. Otherwise the calculations of the modified output ramp time for cells that are further down in the topological order are continued until a cell is reached where the new output ramp time substantially equals the original output ramp time.

Delay computation speed up and incrementality

A method for accounting for negative bias temperature instability in a rise delay of a circuit design, the method comprising the steps of create a cell and net model library with original rise numbers, construct the circuit design from the cell and net models, for each cell and net in the circuit design, calculate an original rise delay, apply a negative bias temperature instability model to determine a parameter shift, determine a new rise number from the parameter shift, and calculate a new rise delay by original rise delay* (original rise number)/(new rise number).

Negative bias temperature instability modeling

A method is provided for selecting a frequency-based ramptime limit for a technology. The method includes creating a logic chain with cells from the technology and applying a sequence of signals to the logic chain. Each signal has a different ramptime relative to a clock period. At least one signal quality characteristic is measured along the logic chain for each of the signals. The frequency-based ramptime limit is selected based on a comparison of the measured signal quality characteristics measured to at least one predefined signal quality value.

Method for estimating a frequency-based ramptime limit

In exemplary embodiments, a method and computer program product for predicting quiescent current variation of an integrated circuit die include steps of: (a) receiving as input a value of a derating factor from a process monitor cell on an integrated circuit die and an on-chip variation of the derating factor; (b) constructing a curve fitting formula for estimating a quiescent current of the integrated circuit die as a function of the derating factor; (c) calculating minimum and maximum values of the quiescent current from the curve fitting formula, the value of the derating factor from the process monitor cell, and the on-chip variation of the derating factor to generate an estimate of minimum and maximum values for the quiescent current; and (d) generating as output the estimated minimum and maximum values of the quiescent current.

Method of predicting quiescent current variation of an integrated circuit die from a process monitor derating factor

A method of calculating delay for a process variation includes finding a value for each of exactly two independent variables that results in a maximum or minimum variation of estimated cell delay plus net delay, calculating a variation of resistance from the value found for each of the exactly two independent variables, calculating a variation of capacitance from the value found for each of the exactly two independent variables, adding the calculated variation of resistance to a net resistance to generate a modified net resistance for a selected net, adding the calculated variation of capacitance to a net capacitance to generate a modified net capacitance for the selected net, and calculating the cell delay plus net delay from the modified net resistance and the modified net capacitance.

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San Jose, CA, United States of America

Qian Cui