Collaborative Research: FuSe:Substrate-inverted Multi-Material Integration Technology

Heterogeneous integration of new materials promises to significantly expand the range of capabilities accessible by silicon photonic integrated circuits (PICs). However, classical integration protocols require custom deep etching through the top layers to access the photonic devices underneath, and thus face severe limitations in integration capacity, density, and process complexity. This program will explore co-design of new materials, integration processes, device architectures, and packaging solutions to realize a transformative universal heterogeneous integration platform: Substrate-inverted Multi-Material Integration Technology (SuMMIT). Upon success, the SuMMIT platform will significantly expand and expedite heterogeneous photonic integration of new materials—a key driving force for PIC technology advances. The program will also strengthen academia-industry partnership and workforce development through development of both online and in-person photonics training programs. The SuMMIT integration scheme leverages advanced wafer-scale 3-D packaging technologies such as through-Si vias and direct bond interconnects to enable seamless integration of materials traditionally considered incompatible with complementary metal-oxide semiconductor processing. Another innovative aspect of the proposed scheme is the use of through-Si vias to establish a bi-facial electrical and optical interconnect configuration, which offers much higher interconnect density and improved electrical performance such as latency and power consumption as compared to peripheral wire-bonding. Furthermore, the SuMMIT platform opens up a plethora of design concepts creatively re-purposing existing components and structures in industry-standard PICs towards facilitating heterogeneous integration. The program’s focus on building on standard PIC processes and structures with minimal customization facilitates industry adoption of the innovations and their integration into the existing semiconductor manufacturing ecosystem. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.