SRAM static noise margin test structure suitable for on chip parametric measurements

摘要

A set of memory cell test structures and a method for assessing of the static noise margin (SNM) of a memory cell or cells, using discrete point measurement structures provided either on-chip or within the scribe lines. A set of memory structures may comprise first and second test structures, individually comprising a memory cell, having one or more left and right half-bit test structures having hard-wired connections between select nodes of each memory cell half-bit and one or more voltage supplies. The half-bits of the first test structure are configured for measuring respective left and right standby SNM values, and the half-bits of the second test structure are configured for measuring respective left and right cell ratio values at respective output nodes of the structures, using applied supply voltages for on-chip assessment of the static noise margin of the memory cells.