Patent ID: 8832619
Filing Date: 2014-09-09
Classification: G06F,H01L

Abstract:
1. A method of characterizing a metal oxide semiconductor (MOS) array comprising the steps of: modeling a metal oxide semiconductor (MOS) array having a plurality of rows and columns defining a set of cells; forming a first subset of cells of the set on a substrate; measuring current for each cell in the first subset of cells; determining standard deviation of current for each cell in the first subset of cells with respect to current of a reference cell in the array; determining standard deviation of local variation as a function of the determined standard deviation of current for one or more cells in the first subset; determining standard deviation of variation induced due to a poly density gradient effect in a first direction as a function of the determined standard deviation of local variation and the determined standard deviation of current for one or more cells in the first subset; and determining standard deviation of variation induced due to a poly density gradient effect in a second direction as a function of the determined standard deviation of local variation and the determined standard deviation of current for one or more cells in the first subset; and performing computations in a processor to characterize a second subset of cells of the set as a function of the determined standard deviation of variation induced due to a poly density gradient effect in the first direction and/or second direction, the second subset comprising one or more cells each mutually exclusive of the first subset of cells.