Precise Alignment and Laser-Assisted Bonding of Multichannel Laser Diode Chips for Silicon Photonics Integration

The accelerating growth of information technologies - driven by AI, cloud services, and Big Data - has intensified the demand for compact, high-throughput photonic integration platforms. Traditional hybrid integration methods such as mass-reflow and thermo-compression bonding face limitations in silicon photonics due to poor scalability, thermal mismatch, and limited alignment precision. To address these challenges, we present a Laser-Assisted Bonding (LAB) approach tailored for heterogeneous photonic integration. LAB enables localized heat application, minimizing thermal stress and warpage — both critical for achieving submicron alignment accuracy. The bonding process is supported by a through-silicon imaging system with bottom illumination architecture, which enables simultaneous visualization and alignment of waveguides on both the III–V chip and silicon photonic circuit. In a proof-of-concept demonstration, a$1 \times 1 \text{mm}$multichannel III–V laser chip was bonded onto a silicon photonics platform. The resulting joint strength of$\mathbf{1 3, 8 7 N}$satisfies MIL-STD-883H shear strength criteria, with negligible post-bond misalignment of$<0,5 \mu \mathrm{m}$. The post-bond LIcharacterization demonstrated optical emission from all four channels with expected output power. The updated bonding process flow, based on the solder dynamic behavior study, ensures reliability and repeatability. These results validate LAB as a fast, energy-efficient, and highly accurate technique for next-generation photonic packaging, capable of meeting the stringent demands of modern silicon photonics manufacturing.