公开(公告)号：EP0997913A1

公开(公告)日：2000-05-03

申请号：EP98830654.4

申请日：1998-10-29

Applicant: STMicroelectronics S.r.l.

Inventor： Riva, Marco ,  Hollandi, Paolo ,  Montanaro, Massimo

IPC: G11C29/00 ,  G11C11/56 ,  G06F11/20

CPC classification number: G11C29/50 ,  G06F2201/81 ,  G11C11/56 ,  G11C11/5642 ,  G11C2029/5006 ,  G11C2211/5634

Abstract: A method for testing virgin memory cells in a multilevel memory device which comprises a plurality of memory cells, the particularity of which consists of the fact that it comprises the steps of:

reading the individual memory cells that constitute a memory device and comparing each one of these memory cells with at least one reference memory cell at a time, so as to determine whether the threshold of the memory cells is lower than the threshold of the at least one reference memory cell or not;
determining the number of the memory cells whose threshold is higher than the threshold of the at least one reference cell;
the at least one reference memory cell being chosen with a gradually higher threshold;
when the number of memory cells whose threshold is higher than a given reference threshold is found to be sufficiently lower than the number of redundancy memory cells provided in the memory device, assuming the given reference threshold as lower reference threshold for the memory device, determining a statistical distribution of the thresholds of the memory cells.

Abstract translation: 一种用于测试多层存储器件中的原始存储器单元的方法，其包括多个存储器单元，其特殊性包括以下事实：其包括以下步骤：读取构成存储器件的各个存储单元，并将 这些存储单元同时具有至少一个参考存储器单元，以便确定存储器单元的阈值是否低于至少一个参考存储器单元的阈值; 确定阈值高于所述至少一个参考小区的阈值的存储器单元的数量; 所述至少一个参考存储器单元被选择为具有逐渐更高的阈值; 当发现阈值高于给定参考阈值的存储单元的数量足够低于设置在存储装置中的冗余存储单元的数目时，假设给定参考阈值为存储器件的较低参考阈值，则确定 存储单元阈值的统计分布。