Built-in testing methodology in flash memory

摘要

An Electric Wafer Sort (EWS) flow is implemented by expanding the functions of the micro-controller embedded in a FLASH EPROM memory device and of the integrated test structures. Test routines are executed by the onboard micro-controllers (that may be reading either from an embedded ROM or from a GLOBAL CACHE provided) internally without involving any external complex or expensive test equipment to control the test program. The device architecture is transparent from a tester point of view, with a standard interface having a set of defined commands and instructions to be interpreted by the on board microcontroller and internally executed.