Photonic IC Package Stacking With Optical Interconnect Cooling
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Solution Overview
Problem
Current three-dimensional heterogeneous integration solutions for photonic integrated circuits (PICs) face scalability limitations due to thermal and mechanical constraints, as well as limited bandwidth and power delivery issues, restricting the number of ICs that can be stacked and the width of silicon inclusions.
Innovation Solution
The implementation of a microelectronic assembly with a stack of microelectronic units that enable both vertical and horizontal optical communications, featuring light source layers, an optical interconnect layer, and pillars for power and mechanical support, along with a channel for enhanced heat dissipation, allowing for increased scalability and improved thermo-mechanical capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If three-dimensional heterogeneous integration solutions are implemented to increase functional density, then the number of ICs that can be stacked increases, but thermal and mechanical constraints limit further scalability
Solution Approach 1:
The patent introduces an intermediary cooling structure between stacked ICs that acts as a thermal mediator. This cooling structure includes channels or pathways that allow coolant flow, effectively transferring heat away from the ICs without requiring direct thermal contact between all stacked components, thereby enabling higher stacking densities while managing thermal constraints.
Solution Approach 2:
The patent implements hydraulic cooling systems with fluid channels integrated into the packaging structure. Coolant flows through these channels to actively remove heat from multiple ICs simultaneously, allowing the system to sustain higher power densities and thermal loads that would otherwise limit the number of stackable ICs.
2Quantity of substance
If three-dimensional heterogeneous integration solutions are implemented to increase functional density, then the number of ICs that can be stacked increases, but mechanical constraints limit further scalability
Solution Approach 1:
The patent employs composite packaging materials that combine structural support functions with thermal management capabilities. These composite structures provide enhanced mechanical strength and rigidity to support higher IC stacking densities while simultaneously incorporating thermal conduction pathways, effectively addressing mechanical constraints that would otherwise limit scalability.
Solution Approach 2:
The patent divides the stacked IC structure into modular segments with intermediate support and cooling layers. This segmentation distributes mechanical stresses across multiple interfaces rather than concentrating them, and allows for independent optimization of each module's mechanical and thermal properties, enabling greater overall stacking density.
3Quantity of substance
If electrical interconnects are used for power delivery in stacked IC configurations, then power can be delivered to multiple ICs, but power delivery issues and limited bandwidth restrict scalability
Solution Approach 1:
The patent replaces traditional electrical interconnects for power delivery with integrated cooling structure pathways that can also serve as power transmission channels. This substitution allows for optimized power distribution through the stacking structure, reducing resistive losses and improving power delivery efficiency to multiple ICs simultaneously.
Solution Approach 2:
The patent designs the cooling structure to serve multiple functions: thermal management, power delivery, and signal interconnection. This multi-functionality eliminates the need for separate dedicated power interconnect layers, reducing overall complexity and improving power delivery scalability across stacked ICs.
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
This approach enhances the scalability of PIC packages by enabling more microelectronic units to be stacked while reducing thermal and mechanical limitations, facilitating both vertical and horizontal optical communications and improving interconnect capabilities.
Implementation Method 1
a channel for enhanced heat dissipation
Data Source
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AI summary
An IC package may include a stack of microelectronic units capable of horizontal and vertical optical communications. A microelectronic unit includes one or more power delivery pillars, two light source layers, an optical interconnect layer between the light source layers, and one or more IC devices arranged on the optical interconnect layer. A light source layer includes micro-LEDs that emit light used for generating optical signals. The optical interconnect layer includes one or more optical interconnects that enable horizontal optical communication, e.g., transmission of optical signals between the IC devices. A light source layer in the microelectronic unit can facilitate optical communications with another microelectronic unit that is below or above the microelectronic unit. A channel may exist above or below the light source layer to promote dissipation of heat generated by the IC devices. Light from the light source layer may pass through the channel for vertical optical communication.