Heterogeneous 3-D Integration Using Self-Assembly and Electrostatic Bonding

To overcome various concerns caused by scaling down the device size in future Large Scale Integrated Circuits (LSIs), it is indispensable to introduce a new concept of heterogeneous 3-D integration in which various kinds of device chips with different sizes, different devices, and different materials are vertically stacked. To achieve such heterogeneous 3-D integration, a key technology of self-assembly and electrostatic bonding has been developed. Exploring new devices for the Internet of Things, we have fabricated several kinds of heterogeneous 3-D LSIs called superchip by stacking compound semiconductor device chip, photonic device chip, and spintronic device chip on CMOS device chips using self-assembly and electrostatic bonding. Furthermore, a new system integration technology using a large-area substrate has been developed to reduce the cost of 2.5-D/3-D system module. A 3-D-stacked image sensor system module for automatic driving vehicle has been fabricated using this technology.