Submount Architecture for Multimode Nodes With Decoupled Thermal Paths
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Solution Overview
Problem
Conventional multimode nodes, such as optical transceivers, are limited by chip-on-board architectures that restrict the size and type of ICs that can be included, and suffer from heat dissipation issues due to coarse pin patterning on PCBs, which becomes more critical with higher power dissipating ICs. Advanced board technologies are expensive, and additional substrates often increase costs and introduce new problems.
Innovation Solution
A submount architecture is introduced, where electro-optical components are mounted on a substrate with finer structuring than the PCB, connected via SMT interconnects, and oriented to emit/receive signals above the PCB, allowing flip-chip bonding of ICs and decoupling heat dissipation paths for optical and electrical components, eliminating chip-to-chip bond wires and enabling larger ICs with improved bandwidth and signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If chip-on-board architecture is used with direct coupling to PCB, then manufacturing simplicity is improved, but IC size and type are limited and heat dissipation is insufficient
Solution Approach 1:
A submount substrate is introduced as an intermediary component between the PCB and the electro-optical components. This submount provides fine-pitch interconnects that enable advanced IC packages (such as BGA and flip-chip) while maintaining manufacturing simplicity through standardized assembly processes. The submount acts as a mediator that resolves the conflict between manufacturing ease and IC versatility.
2Ease of manufacture
If chip-on-board architecture with coarse pin patterning is used, then manufacturing is simpler, but heat dissipation capability deteriorates
Solution Approach 1:
The heat dissipation function is segmented and separated from the PCB by introducing a dedicated submount substrate. The submount provides separate heat dissipation pathways through its own thermal vias and copper layers, independent of the PCB's coarse pin patterning. This segmentation allows each layer to be optimized for its specific function while maintaining overall manufacturing simplicity.
3Temperature
If additional substrates are incorporated to address heat dissipation, then heat dissipation improves, but cost and complexity increase
Solution Approach 1:
The submount substrate is designed to perform multiple functions simultaneously: it provides fine-pitch electrical interconnects for advanced IC packages, establishes dedicated heat dissipation pathways, and serves as a mechanical support structure. This multi-functionality reduces the need for additional specialized components, thereby controlling complexity and cost while achieving improved heat dissipation.
4Adaptability or versatility
If chip-to-chip bond wires are used for interconnection, then component integration is achieved, but bandwidth and signal integrity are limited
Solution Approach 1:
The mechanical chip-to-chip bond wire interconnection system is replaced with a planar electromagnetic field-based PCB trace interconnection system on the submount. This substitution eliminates the bandwidth and signal integrity limitations of bond wires by providing controlled impedance traces with superior electrical characteristics, while maintaining component integration through the submount's fine-pitch interconnect architecture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The submount architecture supports advanced ICs with increased pin counts, enhances bandwidth, preserves signal integrity, and improves heat dissipation by decoupling thermal pathways, accommodating higher data rates while maintaining efficient cooling and reducing manufacturing complexity and costs.
Implementation Method 1
one or more optical components of the electro-optical components dissipate heat along at least a first heat dissipation path and electrical components of the electro-optical components dissipate heat along at least a second heat dissipation path that is distinct from the first heat dissipation path
Data Source
AI summary
Presented herein are a submount architecture for an electro-optical engine, which may be embodied as an apparatus in the form of at least an electro-optical engine and a multimode node, and a method for providing the same. According to at least one example, an apparatus includes a printed circuit board (PCB), a substrate with a finer structuring than the PCB, and electro-optical components. A bottom surface of the substrate is coupled to the PCB and electro-optical components are mounted on a top surface of the substrate. The electro-optical components include one or more optical components arranged to emit optical signals towards and/or receive optical signals from an area above the top surface of the substrate.