Flip-Chip Optical Transceiver Package for High Data Rate
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Solution Overview
Problem
High-speed optical transceivers face limitations in scalability due to parasitic inductance introduced by wire bonding in chip-on-board packaging, which restricts data throughput beyond 25 Gbps/channel.
Innovation Solution
The integration of a driver IC with a photonics IC and a PCB using flip-chip bonding and interposers or chip carriers, reducing parasitic inductance through vertically stacked and horizontally tiled component configurations, and eliminating wire bonds to minimize inductive load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wire bonding is used in chip-on-board packaging, then cost effectiveness and ease of manufacture are improved, but parasitic inductance increases limiting data throughput scalability
Solution Approach 1:
The patent extracts and removes the wire bonding interconnect structure from the packaging system. By eliminating the wire bonds entirely and replacing them with direct flip-chip bump bond connections between the driver IC and photonics IC, the source of parasitic inductance is removed while maintaining manufacturing feasibility through established flip-chip processes
Solution Approach 2:
The patent substitutes the mechanical wire bonding system with an electrical direct-connect system using flip-chip bump bonds. This replacement transitions from a mechanical wire-based interconnect to a direct electrical connection through solder bumps, eliminating the inductive effects of wire loops while enabling higher data throughput
2Ease of manufacture
If wire bonding is used to connect driver IC to photonics IC, then manufacturing simplicity is maintained, but signal integrity deteriorates at high data rates
Solution Approach 1:
The patent merges the driver IC and photonics IC into a tightly integrated flip-chip module with direct bump bond connections. By combining these components in close proximity with direct electrical interconnects, signal integrity is enhanced through reduced electromagnetic interference and minimized transmission path, while the integrated module can be manufactured as a unified assembly
Solution Approach 2:
The patent transitions from planar wire bonding connections to three-dimensional vertical stacking with flip-chip bump bonds. This dimensional change allows direct electrical connection through vertical solder bumps rather than horizontal wire routes, reducing signal path length and improving high-frequency signal integrity while maintaining manufacturing capability
3Device complexity
If traditional wire bonding packaging is used, then packaging complexity remains low, but data throughput scalability is limited beyond 25 Gbps/channel
Solution Approach 1:
The patent changes the fundamental electrical parameters of the interconnect by replacing wire bonds with flip-chip bump bonds. This parameter change reduces parasitic inductance and resistance, enabling the packaging to support higher data rates beyond 25 Gbps/channel while the overall packaging structure remains relatively simple and manufacturable
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
Signal integrity in high-speed applications is dependent on both the underlying device performance and electronic packaging methods. The maturity of chip-on-board (COB) packaging technology using wire bonding makes it a cost beneficial option for the mass production of high-speed optical transceivers. However, wire bonding introduces parasitic inductance associated with the length of the bond wires that limits the scalability of the system for higher data throughput. A high-speed optical transceiver package according to a first proposed configuration minimizes packaging related parasitic inductance by vertically integrating components using flip-chip bonding. A high-speed optical transceiver package according to a second proposed configuration minimizes packaging related parasitic inductance with horizontal tiling of components using a chip carrier and flip-chip bonding.