Integration of a Miniature Multichannel Laser Diode Chip to a Silicon Photonics Integrated Circuit Using Laser-Assisted Bonding

Abstract

The advancement of hybrid integration technology for smaller electronics and photonics systems is exerting increased pressure on the development of new automated processes that enable reliable integration with high throughput. Simultaneously, the integration density and diversity of components in a package, including Micro-Electro-Mechanical Systems (MEMS), wafer-level optics, alongside photonics and III/V optoelectronics, are also on the rise. To address these evolving needs, a novel integration approach based on laser-assisted bonding (LAB) is presented here. In this work, the developed LAB setup employs an original bottom illumination/irradiation architecture, coupled with simultaneous imaging through silicon, facilitating high-precision alignment for photonics waveguides. Moreover, the Automated Power Control of a LAB process enables overheat protection for the bonded surfaces, thereby enhancing the reliability and repeatability of the integration process. In a practical demonstration, we showcase the effectiveness of the LAB process by applying it to integrate a multichannel 1x1mm III/V chip with a silicon photonic integrated circuit. The application of highly localized heat during the LAB process rapidly elevated the temperature of the photonic circuit above the pre-deposited solder layers' melting point. This, in turn, led to successful bond formation with impedance in 0.01-Ω range, accompanied by negligible thermal-induced stress to the bonded surfaces and minimal warpage. These results not only validate the efficiency of the LAB process but also underscore its potential to push the boundaries of photonic integration. Particularly noteworthy is the rapid and energy-effective LAB process, featuring bottom illumination/irradiation and simultaneous through-silicon imaging. Thus, it facilitates bonding and active waveguide alignment - an essential aspect in achieving effective integration in the field of photonics. The obtained results contribute to advancing our photonic integration technology.