Sidewall-Deposited Heat Spreader for Microelectronic Package Thermal Management
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Solution Overview
Problem
Microelectronic packages with multiple stacked layers face challenges in heat dissipation due to thermally insulative encapsulants and overlying package layers, which obstruct heat sink attachment and convective cooling, leading to reduced thermal performance.
Innovation Solution
The integration of sidewall-deposited heat spreader structures and embedded thermal conduits enhances convective and conductive heat transfer, with heat spreader structures covering large package sidewall areas and including projections or porous coatings, and thermal conduits routing heat from semiconductor dies to these structures, promoting efficient heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a copper slug heat sink is attached to the backside of the semiconductor die, then heat dissipation is improved, but the overlying package layer obstructs attachment and covers the copper slug interfering with convective cooling
Solution Approach 1:
The heat spreader structure extends vertically from the copper slug through the package layers to the top surface, utilizing the third dimension (Z-axis) to bypass the obstruction problem. This allows heat to be conducted to the top surface where convective cooling can occur without being blocked by package layers.
Solution Approach 2:
The heat spreader structure acts as an intermediary element that bridges the copper slug heat sink and the external environment. It conducts heat from the copper slug through the package layers to the top surface, enabling convective cooling without direct exposure of the copper slug.
2Temperature
If a copper slug is positioned between stacked package layers, then heat dissipation from the underlying die is improved, but microelectronic components in the overlying layer experience undesired heating
Solution Approach 1:
The heat spreader structure provides localized heat dissipation at the top surface where it is needed, rather than distributing heat broadly through the package layers. This concentrates the cooling effect at the exposed surface while minimizing thermal exposure to components in intermediate layers.
Solution Approach 2:
The vertical extension of the heat spreader creates a direct thermal pathway from the copper slug to the top surface, allowing heat to bypass the horizontal plane where sensitive components are located. This dimensional approach routes heat away from the overlying layer rather than through it.
3Reliability
If the semiconductor die is encapsulated utilizing FO-WLP approach, then packaging protection is improved, but heat dissipation is reduced by the surrounding encapsulant
Solution Approach 1:
The heat management system is segmented into distinct functional zones: the copper slug for heat absorption, the heat spreader structure for heat transport, and the exposed top surface for convective dissipation. This segmentation allows the encapsulant to provide protection while the heat spreader provides dedicated thermal management.
Solution Approach 2:
The heat spreader structure serves as an intermediary between the encapsulated die and the external environment, providing a thermal pathway that bypasses the thermally insulative encapsulant material while maintaining the encapsulation's protective function.
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 improves thermal performance by maximizing convective heat transfer and conductive heat flow, effectively addressing the limitations of stacked microelectronic packages with FO-WLP encapsulation, even when containing multiple layers.
Implementation Method 1
heat spreader structures and embedded thermal conduits, which are conformally deposited over a packaged die prior to encapsulation thereof... embedded thermal conduits can also be provided to promote heat transfer from the packaged die to the heat spreader structure
Implementation Method 2
The heat spreader structures are configured to dissipate heat to an external environment... maximizing convective heat transfer and conductive heat flow
Data Source
AI summary
Microelectronic packages and methods for producing microelectronic packages having sidewall-deposited heat spreader structures are provided. In one embodiment, the method includes providing a package body containing a microelectronic device. A heat spreader structure is printed or otherwise formed over at least one sidewall of the package body. The heat spreader structure is thermally coupled to the microelectronic device and is configured to dissipate heat generated thereby during operation of the microelectronic package.