Embedded Heat Slug in Substrate for Thermal Dissipation

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Solution Overview

Problem

Existing electronic packaging technologies face challenges in efficiently dissipating heat without increasing manufacturing costs, as mounting a heat slug on top of the package adds to assembly costs and can lead to junction temperature increases if not used.

Innovation Solution

Embedding a heat slug within the substrate's dielectric layer, thermally connecting it to multiple metal layers, allows for heat dissipation without direct exposure and reduces thermal resistance, enabling better heat flux and faster dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a heat slug is mounted on top of the package, then heat dissipation is improved, but manufacturing cost increases

Engineering Contradiction:
Improveheat dissipationVSAvoidmanufacturing cost
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent merges the heat slug with the substrate by embedding it within the substrate structure during manufacturing. The heat slug is positioned in a cavity formed in the substrate and thermally coupled to the die through die attach material, combining two previously separate components (heat slug and substrate) into a single integrated structure, thereby eliminating additional assembly steps and reducing manufacturing cost while maintaining effective heat dissipation

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heat slug is embedded in the substrate before the die is mounted. The substrate is prepared with a cavity and the heat slug is positioned within it during substrate fabrication, before subsequent assembly steps. This preliminary integration allows the heat dissipation structure to be in place before the die is attached, streamlining the manufacturing process and reducing overall assembly complexity and cost

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If a heat slug is not used, then manufacturing cost is reduced, but junction temperature increases leading to system failure

Engineering Contradiction:
Improvemanufacturing costVSAvoidsystem reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The heat slug is integrated into the substrate structure itself, forming a unified component that provides both mechanical support and thermal management functions. This merged structure ensures reliable heat dissipation is built into the package foundation, preventing junction temperature increases and system failure while maintaining cost-effectiveness through single-stage manufacturing

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If a heat slug is embedded within the substrate, then manufacturing cost is reduced and heat dissipation is improved, but substrate structure complexity increases

Engineering Contradiction:
Improvemanufacturing costVSAvoidsubstrate structure
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The substrate is segmented to create a cavity that accommodates the heat slug. The substrate structure is divided into regions: the main substrate body, the embedded heat slug, and the die attach region. This segmentation allows each component to be optimized independently while maintaining overall structural integrity and simplifying the embedding process

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heat slug is nested within the substrate structure, with the die then nested on top of the substrate. This nested arrangement allows the heat slug to be contained within the substrate's footprint without increasing the overall package size, and the die to be mounted on the substrate's upper surface, creating a compact, multi-level integrated structure

Inventive Principle:
Principle #7Nested doll (Nesting)

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 minimizes junction temperature increases, reduces manufacturing costs, and allows for thinner, more powerful electronic packages with improved thermal performance and flexible routing.

Implementation Method 1

a metal layer within the dielectric core layer thermally connected to at least one metal layer on top of the dielectric core layer and to at least one metal layer on bottom of the dielectric core layer

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

A heat slug is embedded completely within the dielectric layer... Thermal paths to the heat slug are linked through all of the metal layers

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

A heat slug, or heat spreader, is a rectangular metal plate used to dissipate heat away from electronic devices

Methodology Applied
Scientific EffectHeat dissipation: Heat Sink

Data Source

PatentEP2894950B1Embedded heat slug to enhance substrate thermal conductivity
Publication Date: 2020.07.29 DIALOG SEMICON GMBH
  • EP2894950B1 patent drawingFigure 1~3
  • EP2894950B1 patent drawingFigure 4~5
  • EP2894950B1 patent drawingFigure 6~7

AI summary

An electronic package is fabricated wherein a substrate is provided having three or more layers. A heat slug is embedded completely within the substrate. A die is attached above the substrate. Thermal paths to the heat slug are linked through the ground signal interconnects (traces, vias and planes).