Laser-Assisted Bonding of a Miniature Multichannel Laser Diode Chip to a Silicon Photonics Integrated Circuit with Through-Silicon Alignment

The progression of hybrid integration technology for compact electronics and photonics systems is placing increasing demands on the development of novel automated procedures capable of ensuring reliable integration with enhanced throughput. Concurrently, the complexity and density of components within packages, encompassing Micro-Electro-Mechanical Systems (MEMS), wafer-level optics, photonics, and III-V optoelectronics, are on the rise. To tackle these challenges, a pioneering integration methodology based on laser-assisted bonding (LAB) is introduced. The devised LAB configuration employs an innovative bottom illumination/irradiation design coupled with simultaneous imaging through silicon, facilitating precise alignment for photonics waveguides. Additionally, the implementation of Automated Power Control in the LAB process safeguards against overheating of bonded surfaces, thereby enhancing integration process reliability and repeatability. Through a practical demonstration, we validate the efficiency of the LAB technique by employing it for the integration of a multichannel 1×1 mm III/V chip onto a silicon photonic circuit. The localized application of heat during the LAB process rapidly elevates the temperature of the photonic circuit beyond the melting point of pre-deposited solder layers, resulting in successful bond formation with impedance levels in the hundredths of an Ohm range and shear bond force of 10.3 N/10.3MPa/1050.3gf, satisfying the MIL-STD-883H requirements (Methods 2019.8 and 2011.8F). Importantly, this process minimizes thermal-induced stress on bonded surfaces and mitigates warpage. This demonstration not only verifies the functionality of the LAB process but also underscores its potential to expand the frontiers of photonic integration. Particularly noteworthy is the rapid and energy-efficient nature of the LAB process, featuring bottom illumination/irradiation and simultaneous through-silicon imaging. Consequently, it facilitates bonding and active waveguide alignment-a pivotal requirement for achieving effective integration within the realm of photonics. The outcomes of this study contribute significantly to the advancement of photonic integration technology.