Integrated Substrate With Boron Nitride Heat Sink Bonding

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Solution Overview

Problem

Existing semiconductor packages face issues with high thermal resistance, warpage, and increased costs due to soldering or sintering processes, which also limit the size of semiconductor dies that can be accommodated.

Innovation Solution

The integration of a heat sink directly to a dielectric layer without soldering or sintering, using active metal brazing, and employing a boron nitride-containing dielectric layer, allows for closer trace spacing and improved thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If soldering or sintering processes are used to bond heat sink to substrate, then thermal conductivity is improved, but thermal resistance increases and warpage occurs

Engineering Contradiction:
Improvethermal conductivityVSAvoidthermal resistance and warpage
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent removes the soldering or sintering process entirely from the bonding sequence. Instead of using these high-temperature processes that cause warpage and increased thermal resistance, the invention directly bonds the heat sink to the substrate using a eutectic alloy material that achieves thermal conductivity without the harmful thermal processing steps.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the bonding parameters by using a eutectic alloy material with specific composition (containing锡, 铅, 铋, and/or 镓) that enables bonding at lower temperatures with better thermal properties. This parameter change in material composition allows achieving thermal conductivity improvement without the adverse effects of traditional soldering or sintering processes.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If traditional substrate structures are used, then manufacturing simplicity is maintained, but the size of semiconductor dies that can be accommodated is limited

Engineering Contradiction:
Improvesubstrate structure simplicityVSAvoidsemiconductor die size accommodation
Core Design Contradiction:
Device complexityVSArea of stationary object

Solution Approach 1:

The patent merges multiple functions into the substrate structure by integrating the heat sink directly with the substrate using the eutectic alloy bonding layer. This consolidation eliminates the need for separate bonding processes and intermediate layers, allowing larger semiconductor dies to be accommodated while maintaining manufacturing simplicity through a unified structure.

Inventive Principle:
Principle #5Merging (Combining)

3Strength

If soldering processes are used, then bonding strength is achieved, but production costs increase

Engineering Contradiction:
Improvebonding strengthVSAvoidproduction cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The invention uses a eutectic alloy material that can be applied as a thin, cost-effective bonding layer. This material provides sufficient bonding strength for the heat sink attachment while being more economical than traditional soldering materials and processes, thereby reducing production costs while maintaining the required bonding strength.

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

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 reduces thermal resistance, minimizes warpage, and lowers production costs, enabling larger semiconductor dies to be accommodated on the same substrate size.

Implementation Method 1

a dielectric layer including boron nitride chemically bonded to the conductor layer and to the heat sink with an epoxy

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a dielectric layer including boron nitride chemically bonded to the conductor layer and to the heat sink with an epoxy

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 3

a heat sink including a plurality of fins extending therefrom

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4444674B1Integrated substrates and related methods
Publication Date: 2025.12.24 SEMICON COMPONENTS IND LLC
  • EP4444674B1 patent drawingFigure 1
  • EP4444674B1 patent drawingFigure 2~3
  • EP4444674B1 patent drawingFigure 4~5

AI summary

An integrated substrate (88) may include a conductor layer (92); a heat sink (94) including a plurality of fins extending therefrom; and a dielectric layer (90) including boron nitride chemically bonded to the conductor layer (92) and to the heat sink (94) with an epoxy.