Ring Foot Heat Spreader for Warped PCB Thermal Stability

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Solution Overview

Problem

Conventional heat-radiating components face instability in thermal conductivity due to bending of the wiring board, leading to uneven thermal interface material distribution and reduced heat radiation efficiency, especially when using inexpensive greases that can peel off during board warping.

Innovation Solution

A heat-radiating component with a ring-shaped foot portion surrounding the electronic component's mounting area, thermally bonded to the component via a high thermal conductivity material, and a secondary heat-radiating component on the opposite side of the plate-like portion, allowing flexible adaptation to board warping and maintaining stable thermal conduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the heat spreader is mounted to seal chip capacitors together with the semiconductor chip, then the chip capacitors are protected and integrated into the package, but the distance between the fixed position and chip mounting position becomes long, causing the thermal interface material to fail in following board bending and reducing thermal stability

Engineering Contradiction:

Improveadaptability to board bendingVSAvoidthermal conduction stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The heat spreader is segmented into a plate-like portion and a foot portion, where the foot portion is positioned closer to the chip mounting area. This segmentation allows the foot portion to follow board bending while the plate-like portion maintains structural integrity and seals the chip capacitors.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A thermal interface material is introduced as an intermediary between the heat spreader and the chip to improve thermal conduction. The material accommodates minor misalignments and maintains thermal contact stability even when the board bends.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If inexpensive grease is used as thermal interface material, then manufacturing cost is reduced, but the grease can peel off during board warping leading to increased heat resistance

Engineering Contradiction:

Improvemanufacturing costVSAvoidthermal interface stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The thermal interface material is applied as a thin film or grease layer that can flex and deform with board warping. This flexible application allows inexpensive materials to maintain contact and thermal conduction stability even during board bending.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The thermal interface material serves as a cushioning layer that anticipates and accommodates board warping before it occurs. This pre-positioned flexible layer prevents peeling and maintains thermal contact under varying board conditions.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Adaptability or versatility

If the foot portion is positioned far from the chip mounting area to seal chip capacitors, then component integration is improved, but the thermal interface material cannot follow thermal behavior and bending of the board

Engineering Contradiction:

Improvecomponent integrationVSAvoidthermal interface flexibility

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The heat spreader structure is divided into functional segments: the foot portion positioned near the chip for thermal contact and flexibility, and the plate-like portion extending outward for sealing chip capacitors. This segmentation resolves the conflict between integration and thermal flexibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the heat spreader have different functional qualities: the foot portion is designed for thermal contact and flexibility, while the plate-like portion is designed for sealing and structural support. This local differentiation allows both functions to coexist effectively.

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

The configuration ensures stable thermal conduction and improved heat radiation performance by minimizing the impact of board warping on the thermal interface material, maintaining consistent heat transfer from the electronic component to the heat spreader.

Implementation Method 1

the contact thermal resistance between the surfaces is reduced, thereby allowing smooth heat conduction from the semiconductor element to the heat spreader

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a heat-radiating component (for example, metal heat spreader) for releasing heat generated by the semiconductor element into the atmosphere

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentUS8520388B2Heat-radiating component and electronic component device

Publication Date: 2013.08.27 SHINKO ELECTRIC IND CO LTD

AI summary

A heat-radiating component is bonded via a thermal interface material (TIM) to an electronic component (chip) mounted on a wiring board. The heat-radiating component includes a plate-like portion thermally bonded to the chip through the TIM, and a foot portion formed on a surface which faces the electronic component, of the plate-like portion. The foot portion is formed in a ring shape at a position which surrounds a region corresponding to a mounting area of the electronic component, on the inner side of the periphery of the plate-like portion.