Radiator-Integrated Substrate Warpage Control via Dynamic Pressure

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Solution Overview

Problem

Conventional manufacturing methods for radiator-integrated substrates face challenges such as insufficient warpage suppression, increased production costs, and reduced heat radiation performance due to high surface pressures and complex vacuum processes, particularly when dealing with large-sized metal-ceramic bonded substrates and porous pipe radiators.

Innovation Solution

A manufacturing method involving a ceramic substrate with a long side of 50 mm or more, where the metal circuit board and metal base plate are bonded using a molten metal bonding method, and the radiator is bonded via braze-bonding with a brazing material, applying a surface pressure of 1.0 N/mm² to 5.0 N/mm², ensuring a warpage of 2 μm/mm or less on the metal circuit board's front surface, and utilizing a thickness ratio of metal base plate to circuit board of 2:1 to 6:1 for enhanced heat radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If high surface pressure (8-100 kgf/cm²) is applied during bonding to suppress warpage, then bonding strength is improved, but the partition plate of the radiator deforms and heat radiation performance decreases

Engineering Contradiction:
Improvebonding strengthVSAvoidheat radiation performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies a specific surface pressure range (1.0-5.0 N/mm²) during bonding to achieve optimal balance between bonding strength and warpage suppression without deforming the radiator partition plate, replacing the conventional high pressure (8-100 kgf/cm²) approach

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a curvature radius parameter (R ≥ 6500 mm) for the convex projection to dynamically control the pressure distribution during bonding, allowing the system to adapt between bonding strength and warpage suppression based on geometric parameters

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If vacuum processes and complex bonding methods are used to achieve precise bonding, then bonding precision is improved, but production cost increases

Engineering Contradiction:
Improvebonding precisionVSAvoidproduction cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent employs a self-aligning mechanism where the convex projection on the metal circuit board automatically positions itself against the concave groove on the radiator during bonding, eliminating the need for complex vacuum processes or precision alignment equipment

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The convex projection and concave groove act as intermediary alignment features that facilitate precise bonding without requiring complex bonding equipment or processes, simplifying the manufacturing procedure

Inventive Principle:
Principle #24Intermediary (Mediator)

3Area of stationary object

If the size of the metal-ceramic bonded substrate is increased, then heat radiation area is improved, but warpage suppression becomes insufficient

Engineering Contradiction:
Improveheat radiation areaVSAvoidwarpage suppression
Core Design Contradiction:
Area of stationary objectVSStability of the object's composition

Solution Approach 1:

The patent uses the curvature radius (R ≥ 6500 mm) of the convex projection as a dynamic parameter that scales with substrate size, maintaining effective pressure distribution and warpage suppression across different substrate dimensions while preserving heat radiation area

Inventive Principle:
Principle #15Dynamics

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 method effectively reduces warpage and processing costs while maintaining excellent strength and heat radiation performance, ensuring reliable bonding and efficient heat dissipation in radiator-integrated substrates.

Implementation Method 1

bonding of a metal circuit board and a metal base plate to a ceramic substrate is performed by a molten metal bonding method

Methodology Applied
Scientific EffectMolten metal bonding: Welding

Implementation Method 2

boding of the metal base plate and a radiator is performed by a braze-bonding method

Methodology Applied
Scientific EffectBraze-bonding: Brazing

Implementation Method 3

heat generated from the electronic component and so on is released to air, cooling water or the like by the heat radiation fin or the cooling jacket (radiator) via the metal-ceramic insulating substrate, the solder and the base plate

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 4

heat generated from the electronic component and so on is released to air, cooling water or the like by the heat radiation fin or the cooling jacket (radiator)

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2830403B1Manufacturing method of radiator-integrated substrate and radiator-integrated substrate
Publication Date: 2019.12.18 NIPPON LIGHT METAL CO LTD
  • EP2830403B1 patent drawingFigure 1~2
  • EP2830403B1 patent drawingFigure 3
  • EP2830403B1 patent drawingFigure 4

AI summary

A metal circuit board and a metal base plate are bonded to a ceramic substrate to form a metal-ceramic bonded substrate, then the metal base plate is arranged on one surface of the radiator via a brazing material with the metal base plate overlapping with the one surface of the radiator, a jig having a concave R surface is arranged on another surface of the radiator with the jig butting against the another surface of the radiator, a jig having a convex R surface protruding toward the metal-ceramic bonded substrate is brought into contact with another surface of the metal circuit board, and the metal-ceramic bonded substrate and the radiator are heat-bonded while they are pressurized by the radiator side jig and the metal-ceramic bonded substrate side jig, wherein a curvature radius R (mm) of the convex R surface and the concave R surface is 6500 ≦ R ≦ surface pressure (N/mm2) × 2000 + 12000.