| 摘要 |
<p>PURPOSE:To execute the quality decision and screening, etc. with high accuracy by utilizing a sense amplifier using a dummy memory cell, and applying a prescribed positive voltage to a first gate of a memory cell and a second gate of the dummy memory cell. CONSTITUTION:At the time of testing a threshold voltage Vt1 of a memory cell 60ij in which logic '1' is written, a value of a variable voltage Vm1 at the time of inversion of an output of a sense amplifier 70i is measured by applying a variable voltage Vm1 and a prescribed voltage to a first gate CG1 and a second gate CG2, respectively. At the time of testing a threshold voltage Vt0 of the memory cell 60ij in which logic '0' is written, a value of a variable voltage Vm2 at the time of inversion of an output of the sense amplifier 70i is measured by applying a prescribed voltage Vr and a variable voltage Vm2 to a first gate CG1 and a second gate CG2, respectively. In such a way, both threshold voltages Vt1, Vt0 of the '1' side and the '0' side of the memory cell 60ij can be measured, and the quality decision and screening, etc. can be executed with high accuracy.</p> |
