The product change between batches #1/#2 and the others is the most influential on the test results. The redesign and upgrade to 110-nm process technology reduces the pass rate at LNT by approximately half. This is mainly caused by the increased incidence of erase and program timeouts with some contribution from long erase and program times and bit errors. The difference in pass rates at 88K between batches #3/#4 and #5/#6, which use the same process technology with the same dimensions, can be explained by the fabrication in different assembly lines, where other processes or base materials may have been changed. This means different tolerances in base materials and production process, which are more pronounced the lower the temperature. Some of the differences of technology scale may reflect shifts in transistor parameters such as transconductance/gain, threshold voltage, and threshold slope [7].
