Electrothermal analysis of 3D integrated ultra-fast image sensor with digital frame storage

This paper presents a 3D integrated ultra-fast CMOS image sensor (CIS) with on-chip A/D conversions and digital storage. After an analysis of the burst IS structure and power consumption, it appears that the power density is very high (> 0.1 W/mm²) during the burst video acquisition. Therefore, to evaluate the risk of overheating, a study of the thermal dissipation in the 3D stack is described here. This study has been carried out for different operating modes. The thermal simulations show that in single burst mode, the acquisition time is too short to produce critical overheating. Even in post-event triggering acquisition, the temperature rise should not affect the image quality. Nevertheless, for some high speed applications, it can be mandatory to repeat the burst acquisition over time. This paper demonstrates that for a multi burst mode working in post-event triggering acquisition, the 3D stack can reach high temperature that can damage the system.