IEC 60749-41:2020 pdf free.Semiconductor devices -Mechanical and climatic test methods – Standard reliability testing methods of non-volatile memory devices.
For non-error-corrected devices,any data bit in error counts as a data error. For error-corrected devices,anycodeword or sector (as defined in the product data sheet) returning incorrect data after applying the specified errorcorrection scheme counts as a data error. Transient data errors, such as data errors that occur at a givenprogram/erase cycle but not at later ones, are counted as data errors. Standard statistical confidence levels can beapplied to the numerator.
The cumulative number of bits read is the sum of all bits of data read back from the device, with multiple reads ofthe same memory bit counting as multiple bits read. For example, if a 1-Gb device is read 10 times, then therewould be 10 Gb bits read.
Note 2 to entry: Some devices can be specified to have a certain UBER value, and in this case the qualificationmust determine that the device meets the UBER specification.Clause 5 discusses details regarding calculation ofthe UBER value.
The apparatus required for this test shall consist of a controlled temperature chamber capableof maintaining the specified temperature conditions to within t5 °C.Sockets or other mountingmeans shall be provided within the chamber so that reliable electrical contact can be made tothe device terminals in the specified circuit configuration. Power supplies and biasingnetworks shall be capable of maintaining the specified operating conditions throughout thetest.Also, the test circuitry should be designed so that the existence of abnormal or faileddevices will not alter the specified conditions for other units on test.Care should be taken toavoid possible damage from transient voltage spikes or other conditions that might result inelectrical, thermal or mechanical overstress.
Qualification specifications,including those in JESD47, commonly require that some devicesundergo endurance cycling followed by retention stressing. There may also be retentionrequirements for uncycled devices and for the optional cross-temperature testing across thetemperatures specified in the data sheet. Qualification specifications commonly call forendurance cycling to be performed at multiple temperatures within the datasheet range,andretention stress to be performed both at elevated temperatures,such as 125°C, and roomtemperature. Figure 1 schematically illustrates the flow,with references to the paragraphsdescribing the procedure.IEC 60749-41 pdf download.