Adhesive Properties for Successful Photonic Packaging

The advent of 5G and artificial intelligence (AI) has driven explosive growth in high-speed data communications, spurring the development of new packaging technologies such as 2.5D/3D advanced packaging for AI applications. Among these new technologies, silicon photonics packaging is emerging as a promising alternative to traditional copper-based electronics, offering high-speed and lower power data transmission. Despite significant advancements in electronics packaging, the packaging of photonic integrated circuits (PICs) still faces substantial challenges in achieving high performance and reliability. The silicon photonic packaging process involves numerous technical hurdles, such as the necessity for highly precise and rapid active alignment for optical coupling, reflow and environmental reliability, and managing thermal performance effectively. Adhesives are crucial in various stages of photonic packaging, enabling innovative solutions to these technical challenges. Understanding the critical properties of adhesives that influence the success of packaging applications is essential. Factors such as bond strength, optical transmission efficiency, and resistance to environmental stresses are vital that must be considered. This paper provides a comprehensive overview of the key bonding tasks within a photonic package and explores the specific adhesive requirements. In this context the paper focus on the optical and mechanical properties of adhesives and its capacity to maintain performance under diverse operational conditions. It also highlights advancements in adhesive technologies and their contributions to enhancing the efficiency and reliability of photonic devices, supported by experimental data on coupling efficiency. Furthermore, the paper introduces a novel wafer-level photonic packaging approach that preserves optical properties through wafer-level processing steps such as sawing and grinding. This is achieved by selecting materials with unique optical characteristics, ensuring that the packaging process maintains the integrity and performance of the photonic components.