Backside High-Power Die Heat Sink With Vertical PCB Heat Path

Solution Overview

Problem

Conventional power amplifier modules and RFFE designs face challenges in heat dissipation and mechanical reliability due to top-side mounting of high-power dies, which limits thermal conductivity and increases the risk of overheating and mechanical stress, especially in compact mobile device designs.

Innovation Solution

The solution involves mounting a high-power die on the backside of a package substrate with a heat transfer layer and vertically oriented heat sink interconnects directly coupled to the heat transfer layer, allowing for efficient heat dissipation directly to the PCB and reducing mechanical stress by freeing up space on the package substrate for other components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If high-power die is mounted on top side of package substrate, then routing flexibility is improved, but heat dissipation efficiency deteriorates

Engineering Contradiction:

Improverouting flexibilityVSAvoidheat dissipation efficiency

Core Design Contradiction:

Ease of operationVSTemperature

Solution Approach 1:

The patent inverts the conventional mounting approach by placing the high-power die on the bottom side of the package substrate instead of the top side. This inversion allows the die to be directly coupled to the PCB through the package substrate, creating an efficient vertical heat path from the die through the substrate to the PCB heat sink, thereby resolving the heat dissipation efficiency problem while maintaining routing flexibility through the freed top side layers.

Inventive Principle:

Principle #13The other way round (Inversion)

2Ease of operation

If top-side mounting is used, then routing flexibility is improved, but thermal conductivity deteriorates

Engineering Contradiction:

Improverouting flexibilityVSAvoidthermal conductivity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent inverts the conventional mounting approach by placing the high-power die on the bottom side of the package substrate instead of the top side. This inversion allows the die to be directly coupled to the PCB through the package substrate, creating an efficient vertical heat path from the die through the substrate to the PCB heat sink, thereby resolving the heat dissipation efficiency problem while maintaining routing flexibility through the freed top side layers.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of operation

If top-side mounting is used, then routing flexibility is improved, but mechanical stress increases

Engineering Contradiction:

Improverouting flexibilityVSAvoidmechanical stress

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The patent inverts the conventional mounting approach by placing the high-power die on the bottom side of the package substrate instead of the top side. This inversion allows the die to be directly coupled to the PCB through the package substrate, creating an efficient vertical heat path from the die through the substrate to the PCB heat sink, thereby resolving the heat dissipation efficiency problem while maintaining routing flexibility through the freed top side layers.

Inventive Principle:

Principle #13The other way round (Inversion)

4Ease of operation

If top-side mounting is used, then routing flexibility is improved, but heat sink effectiveness deteriorates

Engineering Contradiction:

Improverouting flexibilityVSAvoidheat sink effectiveness

Core Design Contradiction:

Ease of operationVSTemperature

Solution Approach 1:

The patent inverts the conventional mounting approach by placing the high-power die on the bottom side of the package substrate instead of the top side. This inversion allows the die to be directly coupled to the PCB through the package substrate, creating an efficient vertical heat path from the die through the substrate to the PCB heat sink, thereby resolving the heat dissipation efficiency problem while maintaining routing flexibility through the freed top side layers.

Inventive Principle:

Principle #13The other way round (Inversion)

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 configuration enhances heat extraction efficiency, reduces the risk of overheating, and improves mechanical stability, leading to improved RF performance and extended reliability of high-power dies in compact electronic devices.

Implementation Method 1

a heat transfer layer disposed on the backside of the high-power die

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a plurality of heat sink interconnects coupled to the heat transfer layer, where each of the plurality of heat sink interconnects is directly coupled to the heat transfer layer in a vertical orientation

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11929299B2High-power die heat sink with vertical heat path

Publication Date: 2024.03.12 RF360 EUROPE GMBH

AI summary

Disclosed are apparatuses and methods for fabricating the apparatuses. In one aspect, an apparatus includes a high-power die mounted on a backside of a package substrate. A heat transfer layer is disposed on the backside of the high-power die. A plurality of heat sink interconnects is coupled to the heat transfer layer, where each of the plurality of heat sink interconnects is directly coupled to the heat transfer layer in a vertical orientation.