Manufacturing Technologies for a Highly Reliable, 0.34 μm2-Cell, 64 Mb, and 1T1C FRAM

64 Mb FRAM with a ITIC scheme has progressed greatly for mass production in terms of a highly reliable device. For the first time, package-level reliabilities of the memory were evaluated systematically and massively. We scrutinized the device reliabilities in accelerated manners, one of which is high-temperature-operating-life (HTOL) test; and the other is high-temperature-storage (HTS) test. Random-single-bit failures appeared from the tests were not attributed to intrinsic causes but extrinsic ones. The extrinsic mostly come from poor interconnections between a cell capacitor and its near-contact nodes. As a result of applying novel schemes to remove the analyzed defectives, we have the FRAM with no bit failure up to 1000 hours over both HTOL and HTS tests.