Patent ID: 7982466
Filing Date: 2011-07-19
Classification: G11C

Abstract:
1. An inspection method for a semiconductor memory having nonvolatile memory cells using ferroelectric capacitors, the method comprising the steps, to be executed for each ferroelectric capacitor, of: (a) writing a first polarized state at a first write voltage; (b) after said step (a), heated-shelf-aging said first polarized state; (c) after said step (b), reading said first polarized state at a first read voltage; (d) after said step (c), writing a second polarized state opposite to said first polarized state at a first temperature; (e) after said step (d), heated-shelf-aging said second polarized state; and (f) after said step (e), reading said second polarized state, which has been written at the first temperature, at a second temperature higher than said first temperature, and at a second read voltage, to stress an imprint effect, wherein a retention performance is inspected at said steps (a), (b) and (c), and an imprint performance is inspected at said succeeding steps (d), (e) and (f).