Hsinchu, Taiwan – October 30, 2017
Attopsemi Technology published a paper “32Kb Innovative Fuse (I-Fuse) Array in 22nm FD-SOI with 0.9V/1.4mA Program Voltage/Current and 0.744um2 Cell” for the 2017 IEEE SOI-3D-Subthreshold Microelectronics Technology Unified Conference (S3S). Held in October 16-19, 2017 in San Francisco, IEEE S3S Conference is the only conference dedicated to SOI, 3D IC, and subthreshold technologies.
In the well-received paper in Session10.4, Attopsemi showed how her I-fuse™, a fuse-based OTP (One-Time Programmable) memory, can be very small in size (0.7544um2), low in program voltage (0.9V) and low in program current (<1.4mA) at 22nm FD-SOI process. Based on a 4Kx8 I-fuse™ array, the I-fuse™ can be programmed with current at least 1/20 of an eFuse and with voltage at least 1/5 of anti-fuse in comparable node. Moreover, the OTP IP size is only 1/10 of anti-fuse in comparable nodes since no charge pumps are required as the programming voltage very close to the core voltage of 0.8V. Very low voltage and current programming results in very little damage in I-fuse™ after programming. As a result showed in SEM photos, whether an I-fuse™ has been programmed or not is not easily detectable by top view or by cross section. This paper offered two additional schemes to further increase the data security by lowering the post-program resistance and by programming the virgin I-fuse™ lightly but still read as unprogrammed. Despite the very low voltage/current programming, the cell current distributions of I-fuse™, whether programmed or not, are very tight and can be easily sensed with a proper sense amplifier in most memory designs. The I-fuse™ array also passed HTOL at 150oC for 1,000 hours with virtually no degradation in cell currents. A full blown 4Kx8 I-fuse™ macro at 22nm FD-SOI is also working and will be published in IEEE conference soon.
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