Patent ID: 8447547
Filing Date: 2013-05-21
Classification: G11C

Abstract:
1. A method of designing a memory device to have an estimated yield that satisfies a desired manufacturing yield, the method comprising: designing a circuit corresponding to a memory device that includes a bit cell; storing a data file including a circuit layout and parameters of the circuit; accessing, by a processor programmed to execute circuit simulation instructions, size information from the data file for each of a plurality of transistors within the bit cell, wherein the plurality of transistors includes every transistor in the bit cell; calculating, at the processor, a voltage versus current model for each of the plurality of transistors to generate a voltage transfer curve and to calculate a static noise margin for the bit cell based on static noise margin calculations of the plurality of transistors; determining, at the processor, a mean value of the static noise margin of the bit cell; determining, at the processor, a sensitivity of each of the static noise margin calculations for each of the plurality of transistors; determining, at the processor, a standard deviation value of the bit cell; determining, at the processor, a correlation coefficient of a left static noise margin as compared to a right static noise margin of the bit cell, wherein the correlation coefficient is based on the sensitivity of each of the static noise margin calculations of each of the plurality of transistors; estimating, at the processor, a total static noise margin of the bit cell by evaluating an analytical function based on the mean value, the standard deviation value, and the correlation coefficient; comparing the total static noise margin to a threshold, wherein the threshold is based on the desired manufacturing yield; and in response to the comparison of the total static noise margin to the threshold indicating that the diameter manufacturing yield is not satisfied, modifying one or more physical parameters of the circuit to generate a modified total static noise margin.