Interposer Heat Spreader for PoP Thermal Management
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Solution Overview
Problem
Package on package (PoP) architectures face significant thermal management issues due to high thermal resistance from the bottom die to the top of the PoP, leading to large thermal gradients and constrained performance, especially for core-intensive workloads, and the inclusion of custom memory packages increases costs and complexity.
Innovation Solution
The implementation of an interposer assembly with an integrated heat spreader that extends past the System on a Chip (SoC) and is thermally coupled to a heat sink, reducing thermal resistance and thermal gradients, and shifting thermal interface material to the heat spreader's wings outside the package periphery, along with an interlocking design that minimizes the overall Z-dimension of the PoP system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If underfill material is provided in air gaps between packages, then some thermal resistance improvement is achieved, but the thermal conductivity is not high enough to significantly improve thermal resistance
Solution Approach 1:
The patent changes the thermal parameter by replacing air gaps (low thermal conductivity) with conductive epoxy material (high thermal conductivity). This parameter change in the filling material's thermal properties directly addresses the contradiction by significantly improving thermal resistance while maintaining structural integrity between packages.
Solution Approach 2:
The patent uses composite material construction by combining conductive epoxy with the package structure. The conductive epoxy acts as a thermal interface material that bridges the thermal gap between bottom and top packages, creating a composite thermal pathway that overcomes the limitations of pure air gaps or simple underfill materials.
2Adaptability or versatility
If custom memory packages are included to account for different die architectures, then device functionality is improved, but costs increase and SKU management complexity increases
Solution Approach 1:
The patent implements universality by designing a standardized package interface and thermal management structure that works across different memory die architectures. The conductive epoxy-based thermal solution and package mounting structure are universally applicable, eliminating the need for custom memory packages for different SKUs while maintaining full functionality.
Solution Approach 2:
The patent segments the thermal management function from the memory package itself, using a separate conductive epoxy layer and standardized mounting structure. This segmentation allows the memory die to be universally packaged while thermal performance is optimized through the standardized conductive material interface, reducing SKU complexity.
3Device complexity
If an interposer is used to avoid custom memory packages, then SKU management complexity is reduced, but thermal resistance further increases and package height increases
Solution Approach 1:
The patent extracts the thermal management function from the interposer structure and implements it directly through conductive epoxy material between packages. By removing the interposer and using conductive epoxy to directly bond and thermally connect packages, the solution reduces thermal resistance while maintaining standardized packaging that simplifies SKU management.
Solution Approach 2:
The conductive epoxy acts as an intermediary material that simultaneously provides mechanical bonding and thermal conduction between packages. This intermediary replaces the interposer's functions but with superior thermal properties, reducing thermal resistance while maintaining package standardization.
4Area of stationary object
If traditional PoP architecture is used, then real estate requirements are minimized, but large thermal gradients occur across the processor die leading to constrained performance
Solution Approach 1:
The patent applies local quality by using conductive epoxy material specifically at the thermal interface regions between packages and at critical heat paths within the package structure. This localized application of high thermal conductivity material addresses thermal gradients at the most critical points without requiring changes to the overall compact PoP 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
This solution significantly reduces thermal gradients, enhances performance by up to 35% in sustained operations, and allows for higher burst performance, while also reducing memory costs and inventory management complexities by eliminating the need for custom memory packages.
Implementation Method 1
the conductive epoxy improves the thermal resistance from the bottom die to the top of the PoP
Implementation Method 2
an interposer assembly that comprises an interposer and an integrated heat spreader... thermally coupled to a heat sink... reducing thermal resistance and thermal gradients
Data Source
AI summary
Embodiments disclosed herein include electronic packages with improved thermal performance. In an embodiment, the electronic package comprises a first package substrate, a first die stack over the first package substrate, and a heat spreader over the first die stack. In an embodiment, the heat spreader comprises arms that extend out past sidewalls of the first package substrate. In an embodiment, the electronic package further comprises an interposer over and around the heat spreader, where the interposer is electrically coupled to the first package substrate by a plurality of interconnects. In an embodiment, the electronic package further comprises a second package substrate over the interposer, and a second die over the second package substrate.