Double-Sided PCB Power Block Cooling for Higher Device Density

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Solution Overview

Problem

Conventional cooling methods for semiconductor devices attached to a printed circuit board (PCB) face limitations, such as deformation or fracture of the PCB due to increased device integration and high thermal resistance when heat dissipation occurs through the bottom surface, restricting the number of devices that can be integrated.

Innovation Solution

A cooling apparatus is designed to dissipate heat from both the top and bottom surfaces of semiconductor devices on a PCB, utilizing thermal pads, heat sinks, and thermal interface structures with dielectric layers, along with spring-loaded fasteners to secure the components and enhance heat transfer efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If heat sinks are attached to top surfaces of semiconductor devices mounted over a top surface of a PCB, then heat dissipation is achieved, but the number of semiconductor devices that can be integrated is limited due to PCB deformation, bending, or fracture

Engineering Contradiction:

Improveheat dissipationVSAvoidnumber of semiconductor devices

Core Design Contradiction:

TemperatureVSQuantity of substance

Solution Approach 1:

The patent transitions from single-sided (top surface only) to double-sided mounting, utilizing both top and bottom surfaces of the PCB for semiconductor device integration. This dimensional expansion allows doubling the device capacity without increasing stress on the PCB structure, directly resolving the contradiction between heat dissipation capability and device integration quantity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The cooling apparatus is segmented into separate heat sink assemblies for top-side and bottom-side devices, with independent thermal management paths. This segmentation allows each side to be optimized independently while sharing the same PCB structure, enabling increased device density without compromising structural integrity or thermal performance.

Inventive Principle:

Principle #1Segmentation

2Quantity of substance

If the number of semiconductor devices mounted over the top surface of the PCB increases, then heat dissipation demand increases, but the PCB deforms, bends, or fractures

Engineering Contradiction:

Improvenumber of semiconductor devicesVSAvoidPCB structural stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent employs spring-loaded fasteners that apply controlled compressive force to counteract the thermal expansion and mechanical stress generated by increased device integration. These fasteners act as mechanical counterweights that maintain PCB structural stability while allowing higher device density, preventing deformation and fracture.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The use of spring-loaded fasteners introduces dynamic compliance to the mounting system, allowing the structure to adapt to thermal expansion and mechanical stress in real-time. This dynamic adjustment capability enables the PCB to maintain stability under varying thermal and mechanical loads caused by increased device integration.

Inventive Principle:

Principle #15Dynamics

3Quantity of substance

If heat dissipates through bottom surfaces of semiconductor devices, then device integration is possible, but thermal resistance is high

Engineering Contradiction:

Improvedevice integrationVSAvoidthermal resistance

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent implements different thermal management strategies for top-side and bottom-side devices, with optimized heat sink designs and thermal interface materials tailored to each location's specific thermal requirements. This local optimization reduces thermal resistance at each interface while maintaining high device integration capacity.

Inventive Principle:

Principle #3Local quality

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 approach allows for increased integration of semiconductor devices on a PCB without deformation, while providing efficient heat dissipation, thus improving power density and preventing PCB warpage, and can be scaled for higher power levels.

Implementation Method 1

a first thermal interface structure thermally coupled between the first thermal pad and the first heat sink

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a first heat sink, a first thermal interface structure thermally coupled between the first thermal pad and the first heat sink

Methodology Applied

Scientific EffectHeat sinking: Heat Sink

Data Source

PatentUS20240030096A1Power block based on top-side cool surface-mount discrete devices with double-sided heat sinking

Publication Date: 2024.01.25 UNITED SILICON CARBIDE

AI summary

This disclosure relates to a cooling apparatus and a method for cooling semiconductor devices, wherein the cooling apparatus is disposed over a top surface and a bottom surface of a printed circuit board. The disclosed cooling apparatus comprises a printed circuit board, a first semiconductor device comprising a first thermal pad and mounted on a top surface of the printed circuit, a second semiconductor device comprising a second thermal pad and mounted on a bottom surface of the printed circuit, a first heat sink, a first thermal interface structure thermally coupled between the first thermal pad and the first heat sink, a second heat sink, and a second thermal interface structure thermally coupled between the second thermal pad and the second heat sink.