Copper Heat Spreading Layer for Delamination-Resistant IC Assemblies

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Solution Overview

Problem

Existing heat spreading technologies in semiconductor devices face issues such as delamination due to low contact force with epoxy mold surfaces, high production costs, and lengthy manufacturing times, particularly in bitcoin mining systems where large amounts of heat need to be dissipated.

Innovation Solution

An electronic assembly with a heat spreading copper layer having an average thickness of 3 microns or more, a face-center-cubic structure, and a grain size greater than 0.15 microns, adhered using an epoxy adhesive layer, which occupies the same space as the circuit board and includes a protective layer to enhance heat spreadability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If sputtering or plating technology is used for heat spreading layer, then heat spreadability is improved, but delamination occurs due to low contact force with epoxy mold surface

Engineering Contradiction:

Improveheat spreadabilityVSAvoidadhesive strength

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent changes the thickness parameter of the heat spreading layer from thin (conventional sputtering/plating) to thick (5 microns or more), which improves heat spreadability while the thickness itself provides mechanical anchoring that prevents delamination, resolving the contradiction between heat spreadability and adhesive strength

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite structure combining a thick metal heat spreading layer with epoxy adhesive material, where the metal provides thermal conductivity and the epoxy provides strong adhesion to the mold surface, achieving both heat dissipation and reliable bonding

Inventive Principle:

Principle #40Composite materials

2Temperature

If heat spreading layer with large thickness (5 microns or more) is produced, then heat spreadability is improved, but process cost becomes expensive

Engineering Contradiction:

Improveheat spreadabilityVSAvoidprocess cost

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The patent employs electroplating technology which is a cost-effective method for depositing thick metal layers compared to sputtering, using relatively inexpensive copper or aluminum materials to achieve the desired heat spreading function at lower process cost

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Temperature

If heat spreading layer with large thickness (5 microns or more) is produced, then heat spreadability is improved, but manufacturing time becomes long

Engineering Contradiction:

Improveheat spreadabilityVSAvoidmanufacturing time

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

The patent replaces physical vapor deposition (sputtering) with electrochemical deposition (electroplating), which can deposit metal at much higher rates, reducing manufacturing time while achieving the required thickness for heat spreading

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 reduces production costs and significantly improves heat spreadability by using a thicker heat spreading layer with enhanced adhesive properties, outperforming traditional methods in thermal management.

Implementation Method 1

a heat spreading copper layer disposed on the protective layer, having an average thickness greater than or equal to about 3 microns

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS12463106B2Electric assembly including heat spreading layer

Publication Date: 2025.11.04 3M INNOVATIVE PROPERTIES CO

AI summary

According to an embodiment of the present invention, an electronic assembly comprises: a circuit board including a plurality of connection parts having electrical conductivity; a plurality of spaced apart semiconductor integrated circuits mounted on the circuit board and electrically connected to the plurality of connection parts; a protective layer disposed on the plurality of semiconductor integrated circuits, substantially surrounding the semiconductor integrated circuits, and having a flat upper surface; and a heat spreading copper layer disposed on the protective layer, having an average thickness greater than or equal to about 3 microns, and an average grain size greater than about 0.15 micron, wherein the heat spreading copper layer may occupy substantially the same space in a length and a width as the circuit board (coextensive), and the average thickness of the protective layer may be equal to or greater than the height of the plurality of spaced apart semiconductor integrated circuits.