Photonic Package Wafer-on-Wafer Stacking for 200 Gbps RF Signals
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Solution Overview
Problem
Existing packaging processes for photonic packages are limited to achieving data rates of 100 Gbs RF signals and struggle to meet the goal of 200 Gbs due to high parasitic RF effects from microbumps and require extensive fine-tuning for deep through-silicon-via formation.
Innovation Solution
A face-to-back or face-to-face wafer-on-wafer stacked process is employed to form photonic packages, where optical and electrical components are bonded with a bonding structure, and through-vias are formed with a depth less than 10 μm to reduce parasitic effects and enhance data rate capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deep through-silicon-via (TSV) is formed in electrical components to enable signal transmission, then connectivity between optical and electrical components is achieved, but parasitic RF effects increase and bandwidth is suppressed
Solution Approach 1:
The patent transitions from vertical through-silicon-via connections to lateral surface-mounted interconnects. By changing the dimensional orientation of signal transmission from depth-oriented (vertical) to surface-oriented (lateral), the design eliminates the need for deep TSV structures while maintaining electrical connectivity between optical and electrical components, thereby reducing parasitic RF effects.
Solution Approach 2:
The patent extracts the interconnect function from the bulk substrate (through-silicon-via) and relocates it to the surface level. By separating the signal transmission path from the deep substrate and placing it on the surface, the harmful parasitic effects generated by deep via structures are eliminated while preserving the essential connectivity function.
2Adaptability or versatility
If existing packaging process is used to integrate optical and electrical components, then device integration is achieved, but data rate is limited to 100 Gbs RF signals
Solution Approach 1:
The patent changes the geometric parameters of the interconnect structure by reducing via depth and transitioning to surface-level connections. This parameter modification reduces parasitic inductance and resistance, enabling the system to support higher frequency RF signals and achieve data rates of 200 Gbs, doubling the capability of existing packaging processes.
3Reliability
If deep through-silicon-via formation process is implemented, then electrical connectivity is established, but extensive fine-tuning of process parameters is required
Solution Approach 1:
Instead of forming connections from the top surface through the substrate to the bottom (conventional TSV approach), the patent inverts the approach by establishing connections at the surface level and extending laterally. This inversion eliminates the need for deep etching and complex fill processes, significantly reducing manufacturing complexity while maintaining reliable electrical connectivity.
Data Source
AI summary
A method of producing a photonic package is provided. A first wafer comprising a plurality of optical dies is disposed over a carrier, wherein each of the optical dies include a front side and a back side opposite to the front side, and wherein the front side of each of the optical dies face the carrier. The first wafer is bonded to a second wafer including a plurality of electronic dies, wherein each of the electronic dies include a front side and a back side opposite to the front side, and wherein the front side of each of the optical dies face the back side of each of the electronic dies, respectively. The carrier is removed from the first wafer. The bonded first wafer and second wafer is divided into a plurality of photonic package.