Ceramic Metal Circuit Board Surface Recesses for Resin Adhesion

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Solution Overview

Problem

Ceramic metal circuit boards without a ceramic substrate exhibit insufficient durability and adhesion to molding resin at high operating temperatures, leading to thermal expansion issues and resin peeling.

Innovation Solution

A ceramic metal circuit board is formed by bonding metal circuit plates to a ceramic substrate, with concave portions on the metal circuit plates within a specific area and depth range to enhance adhesion to the molding resin, reducing thermal stress and peeling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a metal circuit board is used without a ceramic substrate, then productivity is improved and manufacturing is simplified, but durability and adhesion to molding resin become insufficient at high operating temperatures

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoiddurability at high temperature
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention uses a composite structure consisting of a metal circuit board bonded to a ceramic substrate. This composite material approach combines the high productivity and ease of manufacturing of metal circuit boards with the high temperature durability and thermal stability of ceramic substrates, resolving the contradiction between manufacturing efficiency and reliability at elevated temperatures.

Inventive Principle:
Principle #40Composite materials

2Power

If the operating temperature of the semiconductor element is raised to improve performance, then power element performance is improved, but thermal expansion increases and adhesion to molding resin deteriorates

Engineering Contradiction:
Improvesemiconductor element performanceVSAvoidthermal expansion stability
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The ceramic substrate in the composite structure has superior thermal stability and lower thermal expansion compared to metal alone. This allows the semiconductor element to operate at higher temperatures for improved performance while the ceramic substrate maintains dimensional stability and prevents excessive thermal expansion that would compromise adhesion to the molding resin.

Inventive Principle:
Principle #40Composite materials

3Strength

If fine concave portions are provided on the metal circuit board to improve adhesion to molding resin, then adhesion is improved, but thermal stress concentration increases at high temperatures

Engineering Contradiction:
Improveadhesion to molding resinVSAvoidthermal stress concentration
Core Design Contradiction:
StrengthVSStress or pressure

Solution Approach 1:

The ceramic substrate provides a stable, low thermal expansion base that reduces overall thermal stress in the structure. This allows the metal circuit board to have fine concave portions for improved resin adhesion without the same degree of thermal stress concentration, as the ceramic substrate absorbs and distributes thermal stresses more effectively than metal alone.

Inventive Principle:
Principle #40Composite materials

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 provides improved adhesion and durability of the ceramic metal circuit board to the molding resin, even at high operating temperatures, by creating an anchor effect through the concave portions, thereby enhancing the reliability of semiconductor devices.

Implementation Method 1

concave portions on the metal circuit plates within a specific area and depth range to enhance adhesion to the molding resin, reducing thermal stress and peeling

Methodology Applied
Scientific EffectMechanical interlocking (anchor effect): Mechanical Fastener

Data Source

PatentEP3608951B1Ceramic metal circuit board and semiconductor device using the same
Publication Date: 2024.07.24 KK TOSHIBA
  • EP3608951B1 patent drawingFigure 1~3a
  • EP3608951B1 patent drawingFigure 3b~4c
  • EP3608951B1 patent drawingFigure 4d~5

AI summary

According to one embodiment, a ceramic metal circuit board is a ceramic metal circuit board formed by bonding metal circuit plates to at least one surface of a ceramic substrate. At least one of the metal circuit plates has an area of not less than 100 mm2 and includes a concave portion having a depth of not less than 0.02 mm within a range of 1% to 70% of a surface of the at least one of the metal circuit plates. The concave portion is provided not less than 3 mm inside from an end of the metal circuit plate. An area to provide the concave portion may fall within a range of 3% to 70% of one metal circuit plate surface.