| 摘要 |
This invention relates to the structure and design of a non-volatile memory, in particular to such memories embedded or integrated into integrated circuits (ICs). To solve the problem of excessive test times for such memories, especially the testing of the associated decoders, a modification of a predetermined, memory-size-dependant number of nonvolatile memory cells turns them into ROM cells with a fixed content pattern. Since these additional ROM cells are just modified non-volatile cells, they differ only slightly from the latter. Thus, they do not require much effort during manufacturing and, even more important, use only small additional space on the memory chip or the integrated circuit, but provide significant advantage for the testing. When using pairs of essentially symmetrical non-volatile memory cells, each pair having a common bit line, the removal or interruption of this bitline contact may serve to impress a fixed value, e.g. a '0', into this pair and vice versa. During test, a simple and therefore only minimal time requiring pattern, preferably a checkerboard pattern, is written into and read from the non-volatile memory, allowing a quick determination of the decoders' correct function. This allows a complete test of the memory's decoders with only minimal time.
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