Package Substrate Cooling Channels for Slim IC Thermal Management
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Solution Overview
Problem
Existing cooling techniques for microelectronic assemblies, including IC packages, are inefficient in transferring heat due to thermal density and mechanical reliability limitations of materials like ceramics and metal alloys, and active systems require pumping a coolant, which complicates heat extraction from IC dies attached to package substrates or PCBs, especially in constrained form factors.
Innovation Solution
A microelectronic assembly with a package substrate featuring a core having a hollow channel for coolant flow and redistribution layers on either side, made of dielectric material with conductive traces and vias, allows for effective heat extraction from within the package substrate, enhancing thermal management and maintaining a slim form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive cooling systems using ceramics or metal alloys are used, then thermal conduction is provided, but thermal density and mechanical reliability limitations prevent effective heat transfer
Solution Approach 1:
The patent applies hydraulic cooling by integrating microfluidic channels directly into the package substrate, allowing coolant flow through the substrate thickness to extract heat from IC dies. This hydraulic approach overcomes the thermal density limitations of passive ceramic or metal alloy systems while maintaining a compact form factor without requiring external pumping mechanisms.
Solution Approach 2:
The cooling channels are merged with the package substrate structure itself, creating an integrated thermal management solution. The substrate serves dual functions as both the electrical interconnect platform and the heat extraction pathway, eliminating the need for separate cooling components and reducing overall device complexity.
2Temperature
If active cooling systems with coolant pumping are implemented, then heat extraction capability is enhanced, but the system complexity and form factor constraints are worsened
Solution Approach 1:
The patent implements passive hydraulic cooling where the coolant flows through microchannels in the package substrate without requiring external pumps. The channel geometry and coolant properties are designed to enable natural circulation or pressure-driven flow, providing effective heat extraction while avoiding the complexity of active pumping systems.
Solution Approach 2:
The cooling system is designed to be self-regulating, where the heat-driven density differences in the coolant or thermal expansion effects create natural circulation currents that automatically adjust to thermal loads without external control mechanisms.
3Loss of energy
If traditional cooling methods are used, then heat transfer is limited, but maintaining compact form factor becomes difficult
Solution Approach 1:
The cooling channels are nested within the package substrate structure, utilizing the substrate's internal volume for heat extraction pathways. This nested arrangement allows effective heat transfer from IC dies without increasing the external dimensions of the package, maintaining a compact form factor while improving thermal management.
Solution Approach 2:
The cooling approach transitions from planar heat dissipation to three-dimensional heat extraction by routing coolant channels through the substrate thickness. This vertical dimension provides additional heat transfer surface area and thermal pathways without increasing the lateral footprint of the package.
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 solution enables improved heat extraction and higher device performance with reduced temperature drops across the package substrate, addressing inefficiencies in existing cooling methods while maintaining a compact design.
Implementation Method 1
a hollow channel configured to permit flow of a coolant... effective heat extraction from within the package substrate
Data Source
AI summary
Embodiments of a microelectronic assembly comprise an integrated circuit (IC) die and a package substrate having a core and redistribution layers on either side of the core. The IC die is coupled to a face of the package substrate, the face being parallel to the core. The core comprises one of glass, ceramic, and metal. The redistribution layers comprise one or more layers of a dielectric material, with conductive traces adjacent to the one or more layers of the dielectric material and conductive vias through the one or more layers of the dielectric material. The core comprises a hollow channel.