Assessing alpha-particle-induced SEU sensitivity of flip-chip bonded SRAM using high energy irradiation

The contribution of alpha particles to soft error rate is quite significant, especially in planar CMOS technology. Due to high packaging density and heat dissipation mitigation technique, microelectronic devices are packaged upside down, which precludes their testing against alpha particles. The ions emitted by alpha isotopes can penetrate neither package nor substrate, from top or backside of the device, respectively, to induce upsets. This paper assesses SRAM single-event upset (SEU) sensitivity against alpha particles using high energies, irradiated from the backside of substrate. The SEU cross-section is measured at alpha various LETs (Linear Energy Transfer) values at the sensitive volume-including the Bragg's peak, for which the sensitivity is maximum. In addition, some insights into high energy alpha backside irradiation are also discussed.