Graphene Molding Compound for Void-Free Semiconductor Package Cooling

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Solution Overview

Problem

Conventional semiconductor packaging materials face challenges with limited thermal conductivity, moisture absorption issues, increased weight, and cost due to the use of traditional thermal additives, which can lead to air pockets and reduced electrical resistivity.

Innovation Solution

A thermally enhanced molding compound incorporating carbon flakes or spherical particles with high thermal conductivity (>450 W/m·K) and electrical resistivity (>90 µΩ.cm), such as graphene or graphite, is used to encapsulate semiconductor dies, minimizing moisture absorption and maintaining low weight and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional thermal additives (silicon oxide, alumina, boron nitride, aluminum nitride, gold, or cooper) are introduced into molding compounds to enhance thermal performance, then thermal conductivity is improved, but moisture absorption increases causing air pockets or voids during reliability testing

Engineering Contradiction:
Improvethermal conductivityVSAvoidmoisture absorption
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent changes the material parameter from conventional thermal additives to carbon-based additives (graphite, carbon fiber, carbon nanotubes) which possess both high thermal conductivity and hydrophobic properties, thereby improving thermal performance while preventing moisture absorption and air pocket formation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials comprising carbon-based additives combined with molding compound materials, creating a composite that achieves both high thermal conductivity and moisture resistance, resolving the contradiction between thermal enhancement and reliability

Inventive Principle:
Principle #40Composite materials

2Temperature

If conventional thermal additives are introduced into molding compounds to enhance thermal performance, then thermal conductivity is improved, but package weight increases

Engineering Contradiction:
Improvethermal conductivityVSAvoidpackage weight
Core Design Contradiction:
TemperatureVSWeight of moving object

Solution Approach 1:

The patent employs carbon-based additives that are lightweight compared to conventional thermal additives like gold or copper, achieving high thermal conductivity without significantly increasing package weight, thus replacing heavier materials with lighter alternatives that maintain performance

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Temperature

If conventional thermal additives are introduced into molding compounds to enhance thermal performance, then thermal conductivity is improved, but electrical resistivity decreases

Engineering Contradiction:
Improvethermal conductivityVSAvoidelectrical resistivity
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent changes the material composition to carbon-based additives which inherently possess both high thermal conductivity and high electrical resistivity properties, simultaneously improving thermal performance while maintaining electrical insulation requirements

Inventive Principle:
Principle #35Parameter changes

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 solution effectively enhances heat dissipation performance while preventing air pockets and maintaining high electrical resistivity, thus addressing the limitations of conventional packaging materials.

Implementation Method 1

The thermal additive has a thermal conductivity larger than 450 W/m·K

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

these thermal additives may cause moisture problems (i.e., the molding compounds may absorb undesired moisture due to the added thermal additives)

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP4270470A1Molding compound thermal enhancement utilizing graphene or graphite materials
Publication Date: 2023.11.01 QORVO US INC
  • EP4270470A1 patent drawingFigure 1A~1C
  • EP4270470A1 patent drawingFigure 2
  • EP4270470A1 patent drawingFigure 3

AI summary

The present disclosure relates to a semiconductor package with a thermally enhanced molding compound. The disclosed semiconductor package includes a module carrier having an upper surface, a die formed over the upper surface of the module carrier, and a thermally enhanced molding compound component formed over the upper surface of module carrier to encapsulate the die. Herein, the thermally enhanced molding compound is formed from a molding compound mixed with a thermal additive and has no air pockets or voids. The thermal additive includes a number of carbon flakes or a number of carbon spherical particles. The thermal additive has a thermal conductivity larger than 450 W/m·K and an electrical resistivity larger than 90 µΩ.cm. In one embodiment, the thermal additive includes a number of graphene flakes, a number of graphene particles, a number of graphite flakes, or a number of graphite particles.