Organic Interposer Packaging for Silicon Photonics LiDAR Modules
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Solution Overview
Problem
Silicon photonics packaging in LiDAR systems faces challenges due to mode field diameter mismatches and tight alignment tolerances, leading to compatibility and integration issues, as well as electrical performance degradation and increased size and cost due to conventional connection methods.
Innovation Solution
Utilizing an organic substrate interposer with a flip chip process to electrically connect photonic integrated circuits (PIC) and electrical integrated circuits (EIC) in LiDAR systems, providing a continuous ground plane and dual thermal paths, and enclosing the components with a metal shroud to reduce crosstalk and protect them from the environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional connection methods are used to connect PIC and EIC, then electrical connection is achieved, but electrical performance degrades and crosstalk increases
Solution Approach 1:
An organic substrate interposer is introduced as an intermediary component between the PIC and EIC. The interposer provides a controlled impedance environment with dedicated ground planes and signal traces, acting as a mediator that prevents direct coupling of electrical signals that would cause crosstalk. The interposer's layered structure with ground planes shields the signal paths, reducing electromagnetic interference while maintaining reliable electrical connections.
2Adaptability or versatility
If conventional packaging methods are used for silicon photonics, then integration is achieved, but mode field diameter mismatch and alignment tolerance issues arise
Solution Approach 1:
The organic substrate interposer serves as a mediator that provides a transition platform between different packaging technologies. It includes interface structures that can accommodate both conventional wire bond connections and advanced flip chip connections, allowing gradual transition and integration while maintaining alignment tolerance through the interposer's mechanical and electrical interface design.
Solution Approach 2:
The interposer enables parameter changes in the electrical connection approach while maintaining optical connection integrity. By changing from wire bond to flip chip connection methods on the interposer, the system can achieve better electrical performance without compromising the optical mode field matching between PIC and fiber, as the interposer decouples these two connection parameters.
3Reliability
If PIC and EIC are connected with multiple connection methods, then electrical connection is achieved, but device size and manufacturing cost increase
Solution Approach 1:
The organic substrate interposer merges multiple functions into a single component: it provides electrical connection pathways, ground planes for shielding, mechanical support structure, and interface adaptation for different connection methods. By combining these functions into one integrated interposer rather than using separate components for each function, the overall device complexity and size are reduced while maintaining reliable electrical connections.
Data Source
AI summary
Various embodiments disclosed relate to semiconductor packaging for photonic modules in LiDAR systems. The present disclosure includes semiconductor assemblies using an organic substrate interposer surface mounted to the printed circuit board, with an electronic integrated circuit die attached to the organic substrate and a photonic integrated circuit die attached to the organic substrate, wherein the electronic integrated circuit die, and the photonic integrated circuit die are electrically coupled to each other through the organic substrate interposer.