3D Die Stack Cooling Wings for Lateral Heat Extraction
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Solution Overview
Problem
Advanced microelectronics packages with three-dimensional stacked dies face performance limitations due to high thermal resistive paths, leading to temperature increases across the stack, which hampers heat dissipation and device performance.
Innovation Solution
Incorporating thermally conductive layers, referred to as thermal cooling wings or sheets, that extend beyond the perimeter of dies to extract heat efficiently, either as rigid materials forming fins for air cooling or flexible materials bending to connect with a heat path outside the stack, connected to a substrate and heat sink for enhanced heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If three-dimensional stacked dies are used to increase integration density, then device functionality and power are improved, but thermal resistive paths increase causing temperature drops across the stack
Solution Approach 1:
The patent introduces thermal cooling wings that extend horizontally from the vertical die stack in a third dimension. These wings conduct heat laterally away from the hot die junctions to heat sinks positioned on the package periphery, creating an additional thermal dissipation pathway that bypasses the limited vertical heat flow path through the die stack.
Solution Approach 2:
The thermal cooling wings act as intermediary thermal conduction elements between the hot die junctions and the heat sinks. Made of highly thermally conductive materials like copper or graphite, these wings serve as thermal mediators that efficiently transfer heat laterally from the confined die stack to the extended heat dissipation structures on the package periphery.
2Loss of energy
If heat is extracted through the die stack to a heat sink, then thermal power dissipation is achieved, but temperature increases on every single device occur
Solution Approach 1:
The patent segments the thermal management function by placing individual thermal cooling wings at multiple die interfaces throughout the stack rather than relying on a single heat sink attachment point. This distributes the heat extraction function across multiple locations, allowing each die to have its own dedicated thermal conduction path to the package periphery, thereby reducing localized temperature increases.
Solution Approach 2:
Instead of extracting heat only vertically through the bottom or top of the stack, the patent extends thermal conduction paths horizontally outward from each die interface using cooling wings. This lateral heat extraction in the horizontal dimension prevents heat accumulation at any single die location and distributes thermal load more evenly across the package.
3Temperature
If thermally conductive layers extend beyond die perimeter to extract heat, then junction temperatures are reduced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent employs thin-film thermal cooling wings made of flexible thermally conductive materials such as graphite or thin copper foils. These flexible thin films can be easily conformally attached to the die surfaces and extend beyond die perimeters without requiring complex rigid structural support, thereby reducing manufacturing complexity while maintaining effective heat extraction.
Solution Approach 2:
The thermal cooling wings utilize composite material structures combining highly thermally conductive materials (copper, graphite) with adhesive layers for die attachment. This composite approach enables the cooling wings to simultaneously provide thermal conduction, mechanical bonding, and structural flexibility, simplifying integration while achieving effective junction temperature reduction.
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 thermally conductive layers significantly reduce junction temperatures by facilitating efficient heat extraction, improving thermal power dissipation and overall package performance, as demonstrated by temperature maps showing reduced temperatures with the implementation of these cooling wings.
Implementation Method 1
the portions of the thermally conductive layers that extend, or otherwise overhang from the dies, may allow heat generated from the various dies to be extracted in a more efficient manner
Implementation Method 2
a heat sink and/or a heat pipe may be connected to the thermally conductive layers
Implementation Method 3
a heat sink and/or a heat pipe may be connected to the thermally conductive layers and may connect the thermally conductive layer to the substrate
Data Source
AI summary
Disclosed herein are microelectronic packages having thermally conductive layers and methods for manufacturing the same. The microelectronics packages may include a substrate and a plurality of dies connected to the substrate and/or each other to form a die stack. The dies may have a perimeter. A thermally conductive layer may be located in between the respective dies. The thermally conductive layers may extend past at least a portion of the perimeters, thereby providing enhanced cooling of the die stack.