Advanced 3D integration TSV and flip chip technologies evaluation for the packaging of a mobile LiDAR 256 channels beam steering device designed for autonomous driving application

Abstract

Lidars are becoming very attractive for autonomous vehicles or robots combined with other sensors. However, in the specific case of autonomous car driving (ADAS), the requirements from vehicle suppliers are very stricts and become critical for the 1 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">st</sup> generation of Lidars based on micro-optics. The required size, the performances to allow fast and accurate detection of obstacle over long distance as well as a limited cost are requiring a new generation of Lidars based on new technologies to realize the beam steering device. This was taken into account for several years by developing solid state optical steering devices (Optical phase Array, OPA) using conventional silicon photonic. The second step come from the complete integration of these devices in the Lidar system. The conventional packaging technology based on wire bonding appears limited in size, density as well as cost and new approaches using collective manufacturing must be evaluated. The work reported here is based on the introduction of advanced 3D & Packaging solutions such as Through Silicon Vias (TSV) and fine pitch flip chip. These solutions are similar to the one chosen for advanced 3D integration for electronic devices and their adaptation to photonic integration with electronics will bring an additional flexibility for heterogeneous integration.