| 摘要 |
A signature structure and method of use for verifying a programmed state of a memory circuit of an integrated circuit is disclosed. The integrated circuit comprises a memory cell, a built-in-self-test cell, a compare cell and a signature cell. The signature cell includes a set of first conductive paths in a first level of conductive material and a set of second conductive paths in a second level of conductive material. The first level of conductive material is separated from the second level of conductive material by an insulating material. A contact structure is placed in a manner such that a first conductive path is in electrical contact with a second conductive path. The selection of a placement of the contact structure is such the first and second conductive paths are electrically coupled to a voltage reference source. The combination of the coupled and uncoupled first and second conductive paths provide the bit states of a reference signature word. The built-in-self-test structure provides addressing data to the memory structure and generates a resulting signature word. The resulting signature word is compared to the reference signature word to generate a status condition of the programmed state of the memory structure. The status condition is used to indicate a pass or fail test result regarding the programmed state of the memory structure.
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